Due to major advances in both diagnosis and treatment of congenital heart disease in children, many are living into adulthood. There are almost one million such patients this year.

Congenital heart disease can be divided into two types:

1. The acyanotic ones in which the oxygen level in the blood is high enough to keep the patients' color pink;

2. The cyanotic ones in which the oxygen level in the blood is low enough for the lips and skin to show varying degrees of bluish discoloration.

1. Acyanotic congenital heart consist of the following:

a) atrial septal defect ( figures 112a, 112b )
b) ventricular septal defect ( figure 112c )
c) patent ductus arteriosus ( figure 22 )
d) aortic stenosis ( figures 24a, 24b, 46a, 46b, 46c, 47 )
e) pulmonary stenosis ( figure 25a, 25b )
f) parachute mitral valve ( figures 44g-1 and 44g-2 )

 

Brickner,M.E. and others,Congenital Heart Disease inAdults,N.Engl.J.Med.,Vol.342.N.4,Jan.27,2000

g)coronary artery fistula

h)anomalies of the great veins

 

Coronary Artery FistuLa

A coronary artery fistula is an abnormal communication between an epicardial coronary artery and a cardiac chamber, major vessel (vena cava, pulmonary veins, pulmonary artery), or other vascular structure (mediastinal vessels, coronary sinus) (cavf -1a,1b,2.,3,4a,and 4b.).In other words,some of the oxygenated blood from the lungs, which has come into the left ventricle and is pumped out into the ascending aorta to feed the coronary arteries and the rest of the body, is being siphoned off by the fistula into the right ventricle ,atrium or other vascular structure.

This infrequent abnormality can affect persons of any age and is the most important hemodynamically significant coronary artery anomaly. Many are small and found incidentally during coronary arteriography, whereas others are identified as the cause of a continuous murmur, myocardial ischemia and angina, acute myocardial infarction,sudden death, coronary steal, congestive heart failure, endocarditis, stroke, arrhythmias, coronary aneurysm formation (rupture, emboli), or superior vena cava syndrome. Some of the symptoms or complications are related to the amount of blood loss into the shunt and how much stress is placed on the left ventricle to compensate.

Of over 33,000 patients undergoing coronary arteriography, coronary artery fistula occurred in 0.1 percent, whether due to congenital or acquired causes (Table see below ). Fistulas from the right coronary artery are more common than from the left, and over 90 percent of the fistulas drain into the venous circulation. Most fistulas are single communications, but multiple fistulas have been identified.

The natural history of coronary artery fistulas is variable, with long periods of stability in some and sudden onset or gradual progression of symptoms in others. Spontaneous closure is uncommon.

Surgical repair of the fistula is recommended for symptomatic patients and for those asymptomatic patients at risk for future complications (coronary steals, aneurysms, large shunts). Transcatheter embolization of fistulas has been reported. Direct connection between a major epicardial coronary artery and a cardiac chamber or major vessel (vena cava,coronary sinus, pulmonary artery) is the most hemodynamically significant coronary artery anomaly(see figures above) Myocardial ischemia has been documented in some patients with coronary artery fistulas, who have no evidence of atherosclerosis.

 

 

 

 

 

cavf-2(coronary fistula-lm-pt-jpg):Diagram showing coronary artery fistula connecting pulmonary trunk and left anterior descending
(LAD) artery. It originalty was misdiagnosed as an anomalous coronary artery. LADD, diagonal branch of LAD;
IC, left circumflex; LM, Left main; R, right.

TABLE 39-3 Causes and Associations of Coronary Artery FistuLa

I. Congenital
1. Embryonic
2. Multiple; systemic hemangioma
II. Acquired
1. Closed-chest ablation of accessory pathway
2. Percutaneous coronary balloon angioplasty8789
3. Hypertrophic cardiomyopathy
4. Right/left ventricular septal myectomy'°'
5. Penetrating and nonpenetrating trauma
6. Acute myocardial infarction
7. Dilated cardiomyopathy
8. Mitral valve surgery
9. "Sign" of mural thrombus
10. Tumor
11. Permanent pacemaker placement
12. Cardiac transplant
13. Endomyocardial biopsy
14. Coronary artery bypass grafting

 

Pathophysiology:

The pathophysiologic mechanism of CAF is myocardial stealing or reduction in myocardial blood flow distal to the site of the CAF connection. The mechanism is related to the diastolic pressure gradient and runoff from the coronary vasculature to a low-pressure receiving cavity. If the fistula is large, the intracoronary diastolic perfusion pressure diminishes progressively.

The coronary vessel attempts to compensate by progressive enlargement of the ostia and feeding artery. Eventually, myocardium beyond the site of the fistula's origin is at risk for ischemia, which is most frequently evident in association with increased myocardial oxygen demand during exercise or activity. With time, the coronary artery leading to the fistulous tract dilates progressively, which, in turn, may progress to frank aneurysm formation, intimal ulceration, medial degeneration, intimal rupture, atherosclerotic deposition, calcification, side-branch obstruction, mural thrombosis, and, rarely, rupture.

Anatomy

Normally, 2 coronary arteries arise from the root of the aorta and taper progressively as they branch to supply the cardiac parenchyma. A fistula exists if a substantive communication arises that bypasses the myocardial capillary phase and communicates with a low-pressure cardiac cavity (atria or ventricle) or a branch of the systemic or pulmonary systems.

Normal thin-walled vessels exist at the arteriolar level that may drain into the cardiac cavity (arteriosinusoidal vessels) and venous communications (thebesian veins) to the right atrium. These small vessels do not steal significant nutrient flow and do not constitute fistulous connections. Fistulae usually are large (>250 mm) and dilated or ectatic, and they tend to enlarge over time. Often, the limits of what constitutes a fistula and what constitutes a normal vessel are debated.

Most fistulae arise from the right coronary artery (60%) and terminate in the right side of the heart (90%). The most frequent sites of termination, in descending order, are the right ventricle, right atrium, coronary sinus, and pulmonary vasculature. Coronary fistula communications often appear in the context of other congenital cardiac anomalies, most frequently in critical pulmonary stenosis or atresia with an intact interventricular septum, but also in pulmonary artery branch stenosis, coarctation of the aorta, and aortic atresia. Although most often congenital, a coronary fistula rarely may arise as a consequence of surgical resection of obstructing right ventricular muscle bundles (as in tetralogy of Fallot), endomyocardial biopsy, or penetrating or blunt trauma.

Embryology

CAF may appear as a persistence of sinusoidal connections between the lumens of the primitive tubular heart that supply myocardial blood flow in the early embryologic period. These channels most often persist when associated with outflow obstruction (eg, pulmonary atresia), yet they also may persist in the absence of obstruction.

Associated syndromes include pulmonary atresia or stenosis with an intact ventricular septum. In this setting, epicardial coronary blood may flow to and fro during the cardiac cycle. In systole, right ventricular flow decompresses via coronary-sinusoidal connections to the aorta in a reverse direction, while in diastole, the aorta perfuses the coronary artery in a normal antegrade fashion. This contrasts with coronary arteriovenous fistulae in the absence of outflow obstruction, in which coronary steal is the primary pathophysiologic problem. In pulmonary atresia and coronary-sinusoidal connections, myocardial ischemia, necrosis, fibrosis, and systemic desaturation may occur. Areas of coronary stenosis and/or interruption of the coronary system may complicate this abnormality. No associated noncardiac conditions exist.

Frequency:

In the US: CAF accounts for 0.2-0.4% of congenital cardiac anomalies. Approximately 50% of pediatric coronary vasculature anomalies are CAFs.

Mortality/Morbidity:

Fistula-related complications are present in 11% of patients younger than 20 years and in 35% of patients older than 20 years. Larger fistulae progressively enlarge over time, and complications, such as congestive heart failure (CHF), myocardial infarction, arrhythmias, infectious endocarditis, aneurysm formation, rupture, and death, are more likely to arise in older patients. Spontaneous closure rarely has been reported.

Surgery-related complications: The mortality rate related to surgical repair of coronary arteriovenous fistulae typically ranges from 0-4%. Variations that may increase surgical risk include the presence of giant aneurysms and a right coronary artery-to-left ventricle fistula. Complications of surgery include myocardial ischemia and/or infarction (reported in 3% of patients) and CAF recurrence (4% of patients).

Race: No race predilection exists.

Sex: No sex predilection exists.

Age: CAF may present in patients at any age, but CAF usually is suspected early in childhood when a murmur is detected in an asymptomatic child. Older children with murmurs may present with symptoms of coronary insufficiency.

Imaging Studies:

Echocardiogram: Two-dimensional echocardiograms may reveal left atrial and left ventricular enlargement as a consequence of significant shunt flow or decreased regional or global dysfunction as a consequence of myocardial ischemia. The feeding coronary artery often appears enlarged, ectatic, and tortuous. High-volume flow may be detected by color-flow imaging at the origin or along the length of the vessel. Carefully seek the site of drainage; often, it is evident as a disturbed flow signal, most frequently within the right ventricle.

Cardiac catheterization remains the modality of choice for defining coronary artery patterns of structure and flow. Most frequently, intracardiac pressures are normal and shunt flow is modest.

Aortography (see cavf-1a,1b) or selective coronary arteriography (see cavf.3,4a,4b ) supplies the information required to manage the condition. In addition, therapeutic embolization using occlusive coils or devices may be performed via catheterization.

Spontaneous closure is rare but may occur in small fistulae. Small fistulous connections in the asymptomatic patient may be monitored. Most lesions enlarge progressively and warrant surgical repair, either by transcatheter or surgical techniques. Provide endocarditis prophylaxis in all patients.

Cardiac catheterization (transcatheter embolization) may be performed as intervention. Initial diagnostic catheterization should both define hemodynamic significance of the lesion and provide detailed angiographic assessment of the anatomy of the abnormality. Surgical options can be delineated by careful identification of the number of fistulous connections, nature of feeding vessel(s), and sites of drainage.

Transcatheter embolization is described as follows:

Indications: In view of the natural progression in larger fistulae to dilate over time, with progressively increasing risk of thrombosis, endocarditis, or rupture, the general advice is to close all but the small fistulous connections. In borderline situations, provide close echocardiographic or angiographic follow-up imaging to identify enlargement of feeding vessel in asymptomatic patients. Patients with large fistulae, multiple openings, or significantly aneurysmal dilatation may not be optimal candidates for transcatheter closure.

Technique: Transcatheter embolization techniques(cavf-4b,before,cavf-4a,after, using coils, bags, or other devices can be performed on an outpatient basis at the time of diagnostic studies or later, and they obviate the need for cardiac surgical intervention. The transcatheter approach frequently is a fairly complicated intervention and requires an experienced operator and interventional specialist with expertise in both coronary arteriography and embolization techniques. Embolization often requires complicated catheter manipulation, as well as selection of various catheters and wires.

Surgical Care: Cardiac surgical intervention is described as follows:

Indications: Indications for surgical intervention are the same as in embolization (see above). Some fistulae are unsuitable for the transcatheter approach and preferably are addressed surgically. These CAFs may include fistulae with multiple connections, circuitous routes, and acute angulations that make catheter positioning difficult or impossible.

Techniques: Surgical repair usually is approached via a median sternotomy and cardiopulmonary bypass. Identify the feeding vessel and delineate its course and site of insertion. Identify the site of presumed fistulous drainage prior to institution of the cardiopulmonary bypass. A typical procedure includes opening the chamber into which the fistula drains, identifying the fistula, and closing the suture. If the fistula enters the ventricle or if the feeding vessel is large, the coronary artery is opened, and the opening to the fistula is closed with a running suture. The arteriotomy is closed. Large aneurysms may require excision. Rarely, when the fistula is an end artery, it may be ligated with or without bypass.

Patients treated surgically and with transcatheter techniques should receive maintenance doses of antiplatelet agents and, perhaps, an anticoagulant regime for the first 6 months postoperatively, until the operative surface has undergone endothelialization.

Patients remain at risk for development of endocarditis until the flow is stopped and should receive antibiotic prophylaxis for any dental, gastrointestinal tract, and urologic procedures.

Complications:

Complications of surgery include myocardial ischemia and/or infarction (reported in 3% of patients) and recurrence of the fistula (4% of patients).

Major complications associated with transcatheter embolization relate to manipulation of stabilizing catheters and wires in the coronary vasculature and may include coronary artery spasm, ventricular dysrhythmias, and perforation. Inappropriate positioning or proximal extension of occlusive coils or devices may result in obstruction of side branches and muscle loss. Intimal dissection of the coronary artery or thrombosis also may occur. However, morbidity and mortality rates generally are considered to be low.

Prognosis:

Further Outpatient Care:

Provide follow-up care after hospital discharge to check for evidence of ischemia or recurrence of fistulae. Individuals who have undergone coronary surgical interventions and, particularly, patients who have sustained cardiac muscle loss should have ongoing cardiac follow-up monitoring that may include stress studies and repeat angiography as needed.

Patients treated surgically and with transcatheter techniques should receive maintenance doses of antiplatelet agents and, perhaps, an anticoagulant regime for the first 6 months postoperatively, until the operative surface has undergone endothelialization.

Patients remain at risk for development of endocarditis until the flow is stopped and should receive antibiotic prophylaxis for any dental, gastrointestinal tract, and urologic procedures.

Complications:

Complications of surgery include myocardial ischemia and/or infarction (reported in 3% of patients) and recurrence of the fistula (4% of patients).

.Major complications associated with transcatheter embolization relate to manipulation of stabilizing catheters and wires in the coronary vasculature and may include coronary artery spasm, ventricular dysrhythmias, and perforation. Inappropriate positioning or proximal extension of occlusive coils or devices may result in obstruction of side branches and muscle loss. Intimal dissection of the coronary artery or thrombosis also may occur. However, morbidity and mortality rates generally are considered to be low.

Prognosis:

Recent results of both transcatheter and surgical approaches indicate a good prognosis. Approximately 4% of patients may require additional surgery for recurrence. Life expectancy is considered normal. However, risk of degenerative atherosclerotic disease may be higher if ectasia and dilatation of the coronary artery persist or progress. In young surgical patients, anticipate the involution of the dilated segment of the feeding vessel; this is not the case in adults.

Abstract

Coronary artery fistula is rare, but it is the most common congenital coronary artery anomaly with hemodynamic significance. It usually causes no symptoms in young patients but may be associated with symptoms and complications in older patients. Surgery has been the traditional treatment. In this report, a 7-year-old girl who had a coronary artery fistula from the left circumflex coronary artery to the right atrium was successfully treated by percutaneous transcatheter technique.

[Chin Med J (Taipei) 1997;59:194-8.]

Keywords: coil, coronary artery fistula, transcatheter embolization

Received: July 23, 1996.

Accepted: November 9, 1996.

Address reprint requests to: Be-Tau Hwang M.D., Department of Pediatrics, Veterans General Hospital-Taipei, No. 201, Sec. 2, Shih-Pai Road, Taipei, Taiwan, R.O.C.
Introduction

Coronary artery fistula is a direct communication between a coronary artery and one of the cardiac chambers or vessels around the heart . Although the fistula is rare, it is the most common congenital coronary artery anomaly with hemodynamic significance . Analyses of large coronary angiographic series show the incidence of 0.1-0.2% . This particular anomaly usually causes no symptom in young patients but may present with symptoms and/or complications in older patients including congestive heart failure, myocardial ischemia, infective endocarditis, atrial fibrillation, pulmonary hypertension and rupture . Because of these complications, surgical closure has been advocated in most reported series . However, surgery usually requires a median sternotomy and cardiopulmonary bypass. The perioperative mortality rates range from 2 to 4 % . In this report, we describe the successful percutaneous transcatheter embolization of a coronary artery fistula by coils.
Case Report

A 7-year-old girl was referred to this hospital because of a heart murmur. Otherwise, she was symptom free, active and thriving. Physical examination revealed a grade 3/6 continuous murmur over the whole precordial area. Chest X-ray showed mild cardiomegaly. Electrocardiogram showed left atrial and ventricular hypertrophy. Two-dimensional echocardiograms disclosed a tortuous, dilated, tubular vessel from the aorta and around the heart. Color Doppler flow mappings demonstrated that the entrance of this abnormal vessel was located at the junction of the right atrium and ventricle. Cardiac catheterization revealed normal right and left ventricular pressures and a significant O2 step-up (74.4% to 88.5%) in the right atrium. The pulmonary to systemic flow ratio (Qp/Qs) was calculated as 2.5 by Fick's principle. Selective coronary angiograms (cavf-4b) disclosed a huge, tortuous, dilated coronary artery fistula from the left circumflex coronary artery with a single opening into the right atrium. A test inflation of a balloon of a 5 Fr Berman catheter showed that it produced complete occlusion without untoward clinical effects or electrocardiographic abnormalities. The coronary artery fistula was then occluded by using the Gianturco coils (Occluding Spring Coil, Cook, U.S.A.) through a 5F Judkins catheter. Three coils sized 10 mm in diameter and 12 cm long, 8 mm in diameter and 10 cm long, and 5 mm in diameter and 8 cm long were introduced sequentially. Transient myocardial ischemia with ST-T change was noted immediately after the procedure but spontaneously recovered one minute later. Postocclusion coronary angiograms (cavf-4a) demonstrated the complete occlusion without residual flow. The previous murmur vanished immediately. The follow-up Doppler echocardiography demonstrated a tiny residual flow into the right atrium 24 hours later. The prophylactic antibiotic, oxacillin, was given 30 minutes before the procedure and then administrated intravenously every 6 hours. However, high fever developed two days later. Blood culture was negative. One week after coil embolization, a pericardial effusion was found by echocardiography. The amount of effusion increased gradually in spite of aspirin administration, and so pericardial tapping was done on the 14th day after coil embolization. A total of 60 ml serosanguinous fluid was drained out and the fluid study revealed WBC 257/cumm, RBC 45,320/cumm, protein 4,400 mg/dl, and sugar 88 mg/dl. No bacteria was isolated from the fluid. The amount of pericardial effusion decreased gradually in the following days and was completely resolved two months after pericardial tapping. Follow-up study four months after coil embolization revealed that the patient is asymptomatic without cardiac murmur. The echocardiographic study showed minimal residual flow without pericardial effusion.
Discussion

Most coronary artery fistulas are believed to arise from the incomplete obliteration of primary myocardial sinusoids . This developmental arrest results in retained continuity between the mature coronary artery and cardiac vein or chamber . Although these fistulas are rare, they may gradually enlarge and become the most common congenital coronary artery anomalies with hemodynamic significance . Diagnostic methods include physical examination, electrocardiography, chest X-ray, echocardiography and angiocardiography. Liberthson et al. found that 91% of patients with these fistulas younger than 20 years were asymptomatic compared to 37% of patients older than 20 years. The symptoms or complications included congestive heart failure, myocardial ischemia, infective endocarditis, atrial fibrillation, pulmonary hypertension and rupture. Myocardial ischemia results from coronary steal, with the fistula acting as a low resistance pathway . Spontaneous closure of a fistula is very uncommon. On the basis of these data, most authors have recommended surgical closure of these fistulas during childhood even in the absence of symptoms . However, surgery requires a median sternotomy and usually cardiopulmonary bypass. The perioperative mortality rates ranged from 2 to 4 % in the literature .

Therapeutic transcatheter embolization of abnormal thoracic vessels was first reported in 1974 . In 1983, Reidy et al. reported the first case of transcatheter embolization of a coronary artery fistula. Since then, several reports had demonstrated the feasibility of transcatheter closure of coronary artery fistulas . Coils, detachable balloons, umbrellas and polyvinyl foam had been used for successful occlusion of these fistulas. The choice among these devices is somewhat arbitrary. Coils cost less than other devices and can be delivered through a smaller catheter . It is imperative that the feeding artery is occluded distal to all normal branches to the myocardium . The risks associated with transcatheter embolization of coronary artery fistulas include coronary artery disruption, pulmonary or systemic embolization, pericardial effusion , myocardial ischemia or infarction . In this case, transient myocardial ischemia occurred because the catheter induced left anterior descending coronary artery spasm during manipulation. The ischemia recovered spontaneously one minute later. Otherwise, aseptic pericardial effusion developed one week after coil embolization. The mechanism of pericardial effusion following transcatheter embolization of coronary artery fistula is unknown. It may be associated with increased hydrostatic pressure of pericardial vessels, pericardial inflammation or be similar to the postpericardiotomy syndrome after open heart surgery . After pericardial tap and anti-inflammatory agents with aspirin, the effusion disappeared gradually. Although there was a small residual flow by echocardiography in the reported case, the flow murmur could not be appreciated.

On the basis of our results and those previously reported , we believe that percutaneous transcatheter embolization is a safe and effective treatment for coronary artery fistulas. When a coronary artery fistula with hemodynamic significance is diagnosed, transcatheter embolization should be considered as a replacement to surgery.

2. Cyanotic Congenital Heart
Disease features bluish discoloration of the skin and lips as opposed to the normal pink appearance. The cyanosis is due to the shunting of systemic venous blood to the arterial circulation causing arterial blood desaturation of oxygen. The size of the shunt determines the degree of desaturation. In adults the most common causes of cyanotic congenital heart disease are tetralogy of Fallot and Eisenmenger's syndrome.

a) Tetralogy of Fallot ( figure 23d )
b) Ebstein's Anomaly ( figure 23e )
c) Transposition of the Great Arteries ( figure 23h )
d ) Eisenmenger's syndrome ( figure 23j )

Brickner,M.E. and others,Congenital Heart Disease in Adults,N.Engl.J.Med.,Vol.342.N4,2000,pp.334-342

a) Tetralogy of Fallot

It is characterized by a large ventricular septal defect (VSD, figure 112c), an aorta that overrides the left and right ventricles, obstruction of the right ventricular (RV) outflow tract, and RV hypertrophy (increased wall thickness). As obstruction in RV outflow tract increases, more blood is shunted through the VSD to the left side of the heart to cause more cyanosis (see figure 23d). Increases in resistance to flow in the general arteries of the body causes less shunting, and decreases cause more shunting to the left.

Symptoms in adults include shortness of breath and limited exercise tolerance. Complications include brain abscesses, strokes and heart infections (see figures 48a, 48c, 48d). Such patients may have enlargement of the distal ends of their fingers called clubbing. Most patients without surgical correction die in childhood.

Echocardiography can establish the diagnosis. Color Doppler can visualize the VSD. Heart catherterization can confirm the diagnosis.

Surgical repair is recommended to relieve symptoms and to improve survival. Complete surgical correction (closure of the VSD and relief of RV outflow obstruction is performed currently when patients are very young. Patients are at risk for heart infections and should thus receive prevention with antibiotics before dental or elective surgical procedures.

Even with repair these patients have a poorer survival rate (apparently due to cardiac causes such as arrhythmias) than that of an age-matched control population. Ventricular arrhythmias can be detected with Holter monitoring in 40 to 50 percent of patients with repaired tetralogy and are most likely to occur in patients who are older at the time of surgical repair and those with moderate or severe pulmonary regurgitation,systolic and diastolic ventricular dysfunction, prolonged cardiopulmonary bypass, or prolongation ot the QRS intreval (to greatwer than 180msec). Patients with repaired tetralogy of Fallot often have atrial fibrillation or flutter, which may cause considerable morbidity.

Patient with repaired tetralogy are at risk for other chronic complications. Pulmonary regutgitation may develop as a consequence of surgical repair of the right ventricular outflow tract. Although even substantial regurgitationcan be tolerated for long periodds, enlargement of the right ventricle eventually occurs, with resultant right ventricular dysfunction, and repair orreplacement of the pulmonary valve may be in required. An aneurysm may form at the site where the right ventricular outflow was repaired;rupture has occurred rarely.

Alternatively,patients may have residual or recurrent obstruction of the right ventricular outflow tract,requiring repeated surgery. Approximately 10 to 20 percent of patients with repaired tetralogy of Fallot have residual ventricular septal defects, and such patients may require repeated sirgery if the defects are of sufficient size. RBBB is common after repair of tetralogy of Fallot, but complete heart block is rare. Finally, aortic regurgitation may occur but is usually mild.

Brickner,M.E. and others,Congenital Heart Disease in Adults,N.Engl.J.Med.,Vol.342.N4,2000,pp.334-342

Late survival is excellent, even in patients who underwent repair during the very early years of open heart surgery. Surgery can not be considered curative,since survival,even in excelllent series is slightly but significantly worse than for a matched control population. The risk factors for an adverse late outcome include older age at surgery, preopoerative congestive heart failure, a previous Potts operation, persistent right ventricular systolic hypertension, and a residual ventricular defect. Late death may be sudden, due to tachyarrhythmias or, very rarely in the current era to conduction disease. Left and right ventricular failure due to right ventricular overload or left ventricular volume overload is another important cause of late death in older patients.
The late functional outcome is excellent for the mayority of patients. Most live normal lives, but the results appear to be better in those undergoing surgery at a younger age. Pulmonary valve replacement can be accomplished with low risk.
Exercise performance is usually impaired when surgery is undertaken in adolescence or adulthood.

 

b) Ebstein's Anomaly

This anomaly is due to a defect in the tricuspid valve (TV) with the septal and posterior leaflets displaced down into the right ventricle, while the anterior leaflet is malformed and abnormally attached to the RV free wall (see figure 23e). This valve often allows blood to regurgitate from the small RV back into the large RA.

Eighty percent of these patients have ASD's through which right-to-left shunting of blood may occur with cyanosis. Such patients are at risk for a paradoxical embolus (blood clot) from the RA through the LA to the brain with abscess(instead of the normal route of an embolus from the legs to the lungs via the right ventricle through the pulmonary valve)and sudden death.

There is usually a heart murmur. EKG abnormalities are often present including WPW syndrome, an atrial tachycardia or rapid heart beat (see figures 2, 3a). Twenty percent have an accessory electrical pathway between the atrium and ventricle (see figure 1) to account for the cardiac arrhythmias.

An echocardiogram can define the abnormalities, and a color Doppler imaging study can determine the presence and size of interatrial shunting.

Management involves prevention of complications, such as heart infection, prevented with antibiotic prophylaxis. Heart failure is treated with diuretics (diuril, lasix, etc) (to eliminate fluid) and digoxin (a heart drug to improve heart muscle contractions). Arrhythmias may be treated with medication or catheter ablation (see figures 3b, 11).

Repair or replacement of TV in conjunction with closure of the interatrial communication is recommended in older patients with severe symptoms despite medical therapy and heart enlargement.

Brickner,M.E. and others,Congenital Heart Disease in Adults,N.Engl.J.Med.,Vol.342.N4,2000,pp.334-342

 

c) Transposition of the Great Arteries

In d-transposition of the great arteries, the aorta arises in an anterior position from RV and the pulmonary artery arises from LV (see figure 23f). In two thirds of cases the ductus arteriosus (see figure 22) and foramen ovale allow communication between the aortic and pulmonary circulations. Severe cyanosis is present. The one third with other defects that permit intracardiac mixing (i.e. ASD figures 112a and 112b, VSD figure 112c, PDA figure 22) are less critically ill with loss of severe cyanosis, but they are at risk of LV failure.

Findings include cyanosis and heart murmur. RVH (increased RV wall thickness) or LVH (increased LV wall thickness) may be present. Chest X ray shows heart enlargement.

Immediate management involves creating intracardiac mixing or increasing its extent:
1) use of infusing of medication, prostaglandine E, to maintain or restore patency of ductus arterioses, 2) the creation of an ASD or both.

Also, oxygen is administered to most patients (to decrease pulmonary [lung] vascular (blood vessel) resistance and to increase lung blood flow), as are digoxin and diuretic drugs like diuril or lasix (to treat heart failure).

Two surgical operations have been used (see figure 23f regarding the atrial switch operation). The atrial switch operation as shown in figure 23f has been replaced by the arterial switch operation in which the pulmonary artery and ascending aorta are transected above the semilunar valves and coronary arteries (see figure 23i), and then switched, so that the aorta is connected to the neoaortic valve (formerly the pulmonary valve) arising from the left ventricle (LV), and the pulmonary artery is connected to the neopulmonary valve (formerly the aorta valve) arising from the RV (see figure 23i). The coronary arteries are relocated to the neoaorta to restore normal coronary circulation. This operation can be performed in neonates (newly born) and is associated with a low operative mortality and an excellent long-term outcome.

Brickner,M.E. and others,Congenital Heart Disease in Adults,N.Engl.J.Med.,Vol.342.N4,2000,pp.334-342

 

The Arterial Switch Operation

Surgical Repair of d-Transposition of the Great Vessels Arterial switch operation for d-TGA with intact ventricular septum

Cardiopulmonary bypass can be conducted in a number of ways, depending on the surgeon's preference or the time required to accomplish complete repair, particularly in the presence of a ventricular septal defect or other anomalies such as coarctation of the aorta or a hypoplastic or interrupted aortic arch. In a patient with D-transposition of the great arteries and an intact ventricular septum, the operation is preferably performed with the patient under either total circulatory arrest or continuous low-flow (50 ml/kg/min) hypothermic perfusion, limiting circulatory arrest time to the few minutes necessary to close the atrial septal defect. In the presence of a ventricular septal defect or other complex associated lesions, two periods of deep hypothermic circulatory arrest are used, interposing 10 to 15 minutes of hypothermic reperfusion is between them, or the arterial switch itself may be performed under continuous low-flow cardiopulmonary bypass, with profound hypothermic circulatory arrest for closure of the ventricular septal defect and other procedures such as repair of an interrupted aortic arch.

Stage I: Preparation

o Aprotinin, solumedrol (30 mg/kg), Regitine (0.1 mg/kg), and prophylactic antibiotics are given preoperatively.
o The sternum is opened, the patient heparinized, and a large segment of pericardium is harvested and prepared with 0.6% glutaraldehyde.
o The coronary arteries and great vessels are inspected.
o The arterial duct is dissected free, as are the left and right pulmonary arteries, including the first pulmonary artery branches in the hilum of each lung. The right pulmonary artery can be dissected prior to bypass, and the left dissected while on bypass.
o The ascending aorta is cannulated as far distally as possible to allow adequate length for the aortic anastomosis. A single venous cannula is placed within the right atrium. The left ventricle is vented with a catheter placed in the right superior pulmonary vein.

Stage II: Cardiopulmonary

o Cardiopulmonary bypass is begun, and the patient cooled for a minimum of 20 minutes to 20°C rectal temperature.
o The arterial duct is doubly ligated and divided, and the branch pulmonary arteries are completely mobilized.
o The site of aortic transection is marked before the cross clamp is applied. This is just distal to the pulmonary artery bifurcation, as best judged by the take-off of the left pulmonary artery.
o At 20°C rectal temperature, the distal ascending aorta is clamped, and cold blood cardioplegia is delivered into the proximal ascending aorta.
o The aorta is divided at the previously marked site, and the main pulmonary artery is divided just proximal to its bifurcation.
stage, adhesions do not usually present a problem. In the unusual situation in which the origin of the left coronary artery cannot be visualized after the banding, the arterial switch operation is deferred (for about 12 months) at which time clear delineation of the coronary anatomy can be made by coronary arteriography and/or magnetic resonance imaging.
o The aortic and pulmonary valves are careftilly inspected, as is the presence of left ventricular outflow tract obstruction.
o The Lecompte maneuver is performed, and the pulmonary artery is held in position anterior to the ascending aorta by moving the aortic cross clamp.
o The anterior commissure of the neoaorta is marked with a silk suture. Alternatively, the exact positions of the implantation sites are identified by juxtaposing the explanted coronary arteries or by placing marking sutures before cardiopulmonary bypass, when the aortic and pulmonary roots are distended.

Stage III: Coronary Transfer

o The ostium, the initial course of the left and right coronary arteries, and the presence of infundibular branches are identified.
o The coronary ostia are excised along with a large segment of surrounding aortic wall, extending the incision well into the base of the sinus of Valsalva.
o The proximal coronary arteries are mobilized sufficiently to avoid tension or distortion. Infundibular branches are very rarely sacrificed.
o The distal aorta is anastomosed to the proximal neoaorta with a continuous 6-0 Prolene or Maxon.
o The coronary implantation sites are prepared by making a neoaortotomy into the left and right anterior aspects of the neoaorta while the aortic cross-clamp is temporarily removed, angling the incisions from posterior to anterior, and using the commissural marking stitch as a guide.
o The coronary ostia are transferred by sewing the coronary flaps to these incisions with a continuous 7-0 Maxon suture.

o When the circumflex coronary artery arises from the right coronary artery, the site of right coronary implantation must be placed either higher than usual on the proximal neoaorta or, occasionally, above the suture line on the distal ascending aorta to avoid distortion of the circumflex artery.
o Adequate mobilization of the right coronary artery is frequently necessary to avoid distortion of the circumflex coronary artery. If the two coronary arteries originate from the same sinus, they can often be included in the same aortic flap (provided there is not an intramural course for one of the coronaries).
o If the coronary ostia are located closely adjacent (paracommissural) to the posterior commissure, excision of a segment of the posterior commissure of the native aortic valve (neopulmonary valve) is often necessary; the resultant neopulmonary regurgitation is generally mild and well tolerated.

Stage IV: Circulatory Arrest

o At this point, the pump is turned off and the venous cannula removed. The atrial communication is closed through a right atriotomy, which, as a rule, can be accomplished by suture closure after balloon septostomy, as there is usually no tissue deficiency.

Stage V: Right Ventricular Outflow Reconstruction

o The atriotomy is closed, and the aortic and venous cannula replaced.
o Cardiopulmonary bypass is resumed and the aortic cross-clamp removed.
o The left ventricular vent is turned on.o The aortic and pulmonary valves are careftilly inspected, as is the presence of left ventricular outflow tract obstruction.
o The Lecompte maneuver is performed, and the pulmonary artery is held in position anterior to the ascending aorta by moving the aortic cross clamp.
o The anterior commissure of the neoaorta is marked with a silk suture. Alternatively, the exact positions of the implantation sites are identified by juxtaposing the explanted coronary arteries or by placing marking sutures before cardiopulmonary bypass, when the aortic and pulmonary roots are distended.

Stage III: Coronary Transfer

.The ostium, the initial course of the left and right coronary arteries, and the presence of infundibular branches are identified.
.The coronary ostia are excised along with a large segment of surrounding aortic wall, extending the incision well into the base of the sinus of Valsalva.
.The proximal coronary arteries are mobilized sufficiently to avoid tension or distortion. Infundibular branches are very rarely sacrificed.
.The distal aorta is anastomosed to the proximal neoaorta with a continuous 6-0 Prolene or Maxon.
.The coronary implantation sites are prepared by making a neoaortotomy into the left and right anterior aspects of the neoaorta while the aortic cross-clamp is temporarily removed, angling the incisions from posterior to anterior, and using the commissural marking stitch as a guide.
.The coronary ostia are transferred by sewing the coronary flaps to these incisions with a continuous 7-0 Maxon suture.

. When the circumflex coronary artery arises from the right coronary artery, the site of right coronary implantation must be placed either higher than usual on the proximal neoaorta or, occasionally, above the suture line on the distal ascending aorta to avoid distortion of the circumflex artery.
o Adequate mobilization of the right coronary artery is frequently necessary to avoid distortion of the circumflex coronary artery. If the two coronary arteries originate from the same sinus, they can often be included in the same aortic flap (provided there is not an intramural course for one of the coronaries).
o If the coronary ostia are located closely adjacent (paracommissural) to the posterior commissure, excision of a segment of the posterior commissure of the native aortic valve (neopulmonary valve) is often necessary; the resultant neopulmonary regurgitation is generally mild and well tolerated.

Stage IV: Circulatory Arrest

.At this point, the pump is turned off and the venous cannula removed. The atrial communication is closed through a right atriotomy, which, as a rule, can be accomplished by suture closure after balloon septostomy, as there is usually no tissue deficiency.

Stage V: Right Ventricular Outflow Reconstruction

.The atriotomy is closed, and the aortic and venous cannula replaced.
.Cardiopulmonary bypass is resumed and the aortic cross-clamp removed.
.The left ventricular vent is turned on.
.Full-flow and rewarming are begun. An additional dose of Regitine 0.1 mg/kg is given in the pump.
.The coronary explantation sites in the neopulmonary artery are then filled, using a single, long, inverted bifurcated patch of 0.6% glutaraldehyde-pretreated, autologous pericardium. An incision is made into the pericardium to fit into the posterior commissure, and the free pericardial edge is sutured to the area of the aorta (neopulmonary artery) corresponding to the explanted coronary flaps, using a continuous 6-0 suture. When the anterior remnant of the aortic wall is reached, the pericardium, at this point cylindrically shaped, is tailored to bridge the distance between the proximal neopulmonary artery and the distal pulmonary artery without tension. Discrepancies in caliber between the proximal neopulmonary artery and the distal pulmonary artery are reconciled with this pericardial extension.
o Alternatively, two separate pericardial patches can be used, one for the site of each coronary donor.
o The relationship of the great vessels will require other certain modifications. With side-by-side great vessels, for example, a Lecompte maneuver is not always performed, and the central stoma in the transverse pulmonary artery is moved to the right pulmonary artery.
o The proximal neopulmonary artery is anastomosed to the bifurcation of the native pulmonary artery. Some authors prefer to place the bifurcated pericardial patch as the first maneuver after removing the coronary arteries from the aorta and before coronary reimplantation in some cases.

Stage IV: Completing the Operation

. Pleural tubes, along with left atrial, right atrial, and pulmonary artery lines are placed and secured, as are atrial and ventricular temporary pacemaker leads. Ventilation is resumed, and the patient is weaned off cardiopulmonary bypass. Neuromuscular blockade, continuous fentanyl sedation, mechanical ventilation, and moderate inotropic support are customarily maintained during the first 12 to 18 hours or until hemodynamic stability is achieved.

Rapid Two-Stage Repair of d-TGA with intact ventricular septum

The First Stage

Through either a right thoracotomy or a midline sternotomy, a 3.5- or 4-mm polytetrafluoroethylene (GoreTex) graft is used to connect the right subclavian artery to the right pulmonary artery. Subsequently, and after minimal dissection, a Dacron-reinforced Silastic band is tightened around the main pulmonary artery to achieve a left ventricular pressure that is approximately 75% of systemic pressure. The pericardium is then loosely closed after thoroughly irrigating the pericardial space with heparinized saline to flush out any residual blood or fibrin clots.

The Second Stage

The only modification required relative to the standard operative approach for the arterial switch operation is to first divide and oversew the modified Blalock-Taussig shunt, and to remove the pulmonary artery band. Because the second stage is carried out an average of 7 days after the first stage,adhesions do not usually present a problem. In the unusual situation in which the origin of the left coronary origin cannot be visualized after the banding,the arterial switch operation is deferred( for about 12 months) at which time clear delineation of the coronary anatomy can be made by coronary arteriography and /or magnetic resonance imaging.

Repair of d-TGA with ventricular septal defect and left ventricular outflow tract obstruction

The conventional treatment for neonates and infants with D-transposition of the great arteries, a ventricular septal defect, and hemodynamically significant left ventricular outflow tract obstruction has been an initial Blalock-Taussig shunt. However, either direct relief of the obstruction is attempted, accompanied by ventricular septal defect closure and an arterial switch operation, or, in the case of a long-segment hypoplastic left ventricular outflow tract obstruction or valvar pulmonary stenosis, a Rastelli operation using a cryo-preserved valved aortic or pulmonary homograft is performed (particularly in the neonate or young infant in whom the severe cyanosis is due in part to poor mixing, in spite of the possibility of adequate or even over circulation of the pulmonary vascular bed).

Arterial switch operation, ventricular septal defect closure, and direct resection of LVOTO

The occasional discrete subpulmonary membrane or excrescence of endocardial cushion tissue is easily resected through the posterior (pulmonary) semilunar valve. More common, and surgically more demanding, is left ventricular outflow tract obstruction caused by a posteriorly deviated outlet septum.

Once the ascending aorta and main pulmonary artery are divided in the course of an arterial switch operation, the obstructing muscle is more safely exposed through the pulmonary semilunar valve. Although exposure of the outlet septum is often easier through the anterior (aortic) semilunar valve, in patients with D-transposition of the great arteries, incision and excision of the outlet septum via the aortic valve run the risk of damaging the pulmonary valve, because the pulmonary semilunar valve originates at a lower level than the aortic semilunar valve. Therefore, the trans-pulmonary approach allows a more aggressive excision of the posteriorly deviated outlet septum, at the same time leaving sufficient muscle to anchor the ventricular septal patch. It helps to engage the outlet septum with a skin hook and to deliver it further into the left ventricular outflow tract before excising the muscle mass.

Rastelli operation for d-TGA

Often, in the case of a long, hypoplastic left ventricular outflow tract, resection is not feasible. In such cases a Rastelli operation is preferred to a palliative shunt operation, regardless of the patient's age. After opening the chest through a midline sternotomy, an appropriate-size valved homograft (aortic or pulmonary) is selected, usually varying in size from 9 mm for a neonate to 14 mm for an older infant. In addition, a patch of pericardium is harvested and pretreated with 0.6% glutaraldehyde for later use to augment the anastomosis from the right ventricle to the homograft. Depending on the age and size of the child, either circulatory arrest or cardiopulmonary bypass with low-flow hypothermic perfusion is used. The main pulmonary artery commonly lies posterior and to the left of the ascending aorta, and its branches are dissected and the ligamentum arteriosum divided. If continuous cardiopulmonary bypass is used, the aorta is cross clamped at 25°C, and cold cardioplegia is injected. A vertical right ventriculotomy is then made to expose the aortic valve, the ventricular septal defect and the tricuspid valve. Unless the malaligned septal defect is larger than the diameter of the aortic valve, it is enlarged by making two incisions (at 2 o'clock and 4 o'clock) into the anterosuperior limb of the septal band. The intervening muscle is excised. This maneuver is important to achieve an unobstructed pathway between the left ventricle and the aorta. Interrupted horizontal mattress sutures, reinforced with Teflon pledgets, are placed first along the posteroanterior rim of the defect in a manner similar to the technique used for closure of a malaligned ventricular septal defect in tetralogy of Fallot. Additional interrupted stitches are then placed within the remaining circumference of the pathway from the left ventricle to the aortic valve. A baffle is then tailored from a tubular Dacron conduit (retaining approximately 50% of the circumference of the conduit), measuring the distance from the enlarged ventricular septal defect to the aortic valve rim. The sutures placed along the anterior border of the ventricular septal defect and the posteroanterior aspect of the ventricular defect are first threaded through the Dacron baffle and then tied in place. This partial fixation of the baffle offers the opportunity for adjustments in its length or width. The remainder of the sutures are then passed through the Dacron patch and tied. The Dacron baffle should contribute approximately 50% to the circumference of the pathway from the left ventricle to the ascending aorta, the remainder being composed of the patient's own tissue. Next, either the aortic or the pulmonary valve homograft is prepared to cover the distance between the distal main and proximal left pulmonary artery and the right ventriculotomy. To avoid extrinsic compression of the homograft, the conduit is aligned along the left heart border; the left mediastinal pleura is opened to gain additional space for the conduit. After doubly ligating the main pulmonary artery proximally, the distal conduit-to-pulmonary artery anastomosis is fashioned with a 6-0 continuous suture. At this point the aortic cross clamp is removed. During rewarming, the anastomosis between the right ventricle and the homograft is begun at the most distal part of the ventriculotomy incision and is extended to include approximately 50% of the circumference of the proximal homograft stoma. At that point, the glutaraldehyde-preserved pericardial patch is sewn to the remaining part of the right ventriculotomy and to the free edge of the proximal homograft. This technique eliminates distortion of the anastomosis and ensures unobstructed flow through the homograft. After the air is vented and effective cardiac action has resumed, the infant is weaned from cardiopulmonary bypass. Catheters are routinely placed in the left and right atria and also in the trans-homograft pulmonary artery for postoperative monitoring.

The Arterial Switch Operation for Double Outlet Right Ventricle

An arterial switch operation is indicated for double outlet right ventricle which is at the dtransposition end of the spectrum - when there is little to no pulmonary or subpulmonary stenosis. It may be possible to resect muscular or fibrous tissue from the subpulmonary region as long as there is no important straddling mitral valve chordae. Similarly, a bicuspid pulmonary valve should not be considered an absolute contraindication to an arterial switch, particularly since both an atrial inversion procedure or a complex intraventricular repair with a conduit may result in a lesser quality of life

The general principles of the arterial switch operation for double outlet right ventricle are identical to those employed in the operation for d-transposition. The procedure is generally performed using low-flow hypothermic bypass for the extracardiac portion of the procedure while the intracardiac steps (i.e., closure of the atrial and ventricular septal defects) are conveniently performed during a period of circulatory arrest. Division of the great arteries is followed by inspection of the pulmonary valve and left ventricular outflow tract to ensure that there is no important outflow tract obstruction that might increase the risks from an arterial switch. Coronary mobilization and transfer are performed, followed by the aortic anastomosis. It is preferable not to undertake closure of the intracardiac communications before these steps are taken, as they will allow venting of left heart

The Arterial Switch Operation for Double Outlet Right Ventricle

An arterial switch operation is indicated for double outlet right ventricle which is at the dtransposition end of the spectrum - when there is little to no pulmonary or subpulmonary stenosis. It may be possible to resect muscular or fibrous tissue from the subpulmonary region as long as there is no important straddling mitral valve chordae. Similarly, a bicuspid pulmonary valve should not be considered an absolute contraindication to an arterial switch, particularly since both an atrial inversion procedure or a complex intraventricular repair with a conduit may result in a lesser quality of life

The general principles of the arterial switch operation for double outlet right ventricle are identical to those employed in the operation for d-transposition. The procedure is generally performed using low-flow hypothermic bypass for the extracardiac portion of the procedure while the intracardiac steps (i.e., closure of the atrial and ventricular septal defects) are conveniently performed during a period of circulatory arrest. Division of the great arteries is followed by inspection of the pulmonary valve and left ventricular outflow tract to ensure that there is no important outflow tract obstruction that might increase the risks from an arterial switch. Coronary mobilization and transfer are performed, followed by the aortic anastomosis. It is preferable not to undertake closure of the intracardiac communications before these steps are taken, as they will allow venting of left heart return to the single right atrial cannula. The single cannula is preferred to two caval cannulae for the same reason, as well as for the improved exposure provided by one cannula as compared with two.

The ventricular septal defect may be approached through the anterior semilunar valve, through the right atrium, or through a right ventriculotomy, as determined by the specific anatomic situation. Often there is some element of subaortic narrowing, so a right ventricular infundibular incision serves a dual purpose: access for closure of the ventricular septal defect and access for placement of an infundibular outflow patch to relieve outflow tract obstruction Approach through the semilunar valve or ventriculotomy often allows continuation of bypass throughout closure of the ventricular septal defect. The atrial septal defect is closed through a short, low right atriotomy, with the left heart filled with saline to exclude air before tying the suture.

With bypass re-established, the aortic cross clamp is released. Perfusion of all areas of the myocardium is checked. A single large pericardial patch is used to reconstruct the coronary donor areas, although to obtain optimal exposure, this step may be performed before the intracardiac steps. It is important that the pericardial patch actually supplement the neopulmonary artery (i.e., the patch needs to be quite a bit larger than the excised coronary buttons, because the aorta is frequently somewhat smaller than the pulmonary artery, particularly if there is a long and somewhat narrow subaortic conus). The pulmonary anastomosis is fashioned, and the patient is weaned from bypass. Specific variations of the arterial switch operation for double outlet right ventricle include:

Coronary patterns.

Unusual coronary patterns are much more common with side-by-side great arteries than in standard transposition with anteroposterior great arteries. A common pattern is an anterior origin of the right and left anterior descending coronary arteries from a single ostium, with the circumflex originating from a posterior facing sinus. Extensive mobilization of the right coronary is necessary to prevent tethering of the anterior coronary, which must be transferred directly away from the line of the right coronary. Infundibular and right ventricular free wall branches of the right and anterior descending coronaries should be extensively mobilized from their epicardial beds to prevent tension on the arteries and on the anastomosis. On occasion, an autologous pericardial tube extension of the coronary artery can be used to avoid excessive tension. Excessive tension will be manifested by persistent bleeding from the coronary anastomosis and early or late coronary insufficiency. Another common coronary pattern with side-by-side great arteries is origin of the right and circumflex coronaries from the posterior sinus, with the left anterior descending artery originating from the anterior-facing sinus. It is important to guard against compression of the anteriorly transferred coronary by the posterior wall of the main pulmonary artery.

Closure of the ventricular septal defect.

Exposure of the ventricular septal defect associated with double outlet right ventricle may present special difficulties. The defect may be quite leftward and anterior in what almost appears, from the surgeon's perspective, to be a separate, leftward, blind-ending infundibular recess Exposure through the anterior semilunar valve and right atrium is particularly difficult, and even through a right ventriculotomy it may not be easily seen. Although exposure may be achieved through the original pulmonary valve, this is usually not recommended because of the risk of damage to the conduction system and the neoaortic valve. An additional complication to ventricular septal defect closure in this setting is the tendency for the very leftward ventricular septal defect to extend into the anterior trabeculated septum - that is, there appears to be no clear leftward and anterior margin to the defect. By taking large bites with pledgetted sutures, the size of any residual ventricular septal defect can be minimized. Catheter-delivered devices have been useful for ultimate closure of residual ventricular septal defects in this area.

Multiple ventricular septal defects.

Surgical closure of multiple muscular ventricular septal defect as well as large subpulmonary ventricular septal defect may be difficult and may consume an excessive amount of circulatory arrest time. One approach to this problem is intraoperative delivery o a double-clamshell device. After division of the two great vessels, an excellent view is obtained of both sides of the ventricular septum. The sheath loaded with the device is introduced through the right atrium and tricuspid valve into the right ventricle A right-angled instrument is passed through the original pulmonary valve into the left ventricle through the ventricular septal defect, and into the right ventricle, where it grasps the delivery pod The pod is drawn into the left ventricle, and the lei ventricular arms are released under direct vision The pod is then carefully pulled back into the right ventricle, and, viewing through the original aortic valve into the right ventricular arms are released. If necessary, multiple devices may be placed. Although this system has worked well for children weighing more than 4 to 5 kg, the delivery pod requires further modification for neonates and infants weighing less than 4 kg.

Pulmonary artery anastomosis.

Although the Lecompte maneuver is uniformly useful for patients with standard transposition in which the great arteries are positioned antero-posteriorly (or relatively close to this), for side-by-side great arteries judgment is required in deciding whether translocation of the right pulmonary artery anterior to the aorta will be useful in decreasing tension on the right pulmonary artery. In general, if the aorta is the slightest bit anterior to the pulmonary artery a Lecompte maneuver should be performed. Another consideration in this decision, other than just the tension on the right pulmonary artery, is the relationship of the transferred coronary arteries to the pulmonary artery. Care must be taken to ensure that there is no compression of the coronary arteries. A useful maneuver to minimize the risk of coronary compression, as well as to decrease the tension on the pulmonary artery anastomosis, is to shift the anastomosis somewhat from the original distal divided main pulmonary artery into the right pulmonary artery. The leftward end of the main pulmonary artery is closed (usually by direct suture, although the pericardial patch used to fill the coronary donor areas may be extended here), and the orifice is extended into the right pulmonary artery. In other respects the anastomosis is performed in the usual fashion. This maneuver has the effect of shifting the main pulmonary artery rightward so that it will not lie anterior to the aorta where it would likely cause compression of the anteriorly transferred coronary artery.

Repair of subaortic stenosis and arch anomalies.

The long subaortic conus associated with double outlet right ventricle toward the D-transposition end of the spectrum may cause some degree of subaortic stenosis. Not surprisingly, aortic arch hypoplasia and coarctation often accompany such subaortic stenosis. There is likely to be considerable disparity between the diameters of the great vessels. During the preliminary phase of the arterial switch procedure tourniquets should be loosely applied around the head vessels. The coronary transfer should be undertaken in the usual fashion, using low-flow bypass. The circulation is then arrested, the tourniquets are tightened, and the aortic cross clamp is removed. An incision is made along the lesser curve of the ascending aorta and arch, extending across the coarctation. A long patch of pericardium is sutured into this aortotomy, which serves to minimize the disparity between the proximal neoaorta and the distal ascending aorta. The aortic cross clamp is reapplied, and bypass may be recommended. The remainder of the procedure is undertaken as described previously. Coarctation repair and pulmonary artery banding are not favored as preliminary maneuvers.

http://www.pediheart.org/practitioners/operations/ASO.html

d) Eisenmenger's Syndrome

This consist of a large left (L) to right (R) shunt, which causes severe pulmonary (lung) vascular disease and high blood pressure (in the lungs) with resulting reversal of the direction of shunting (figure 23j). This shunting with increase pressure causes the lung arteries to narrow due to thickening of their walls (especially the middle wall, called tunica media, see figure 23j) and cause obstruction. Initially the changes may be reversible, but ultimately they become irreversible due to inflammation of the arteries. Hence, much of the lung arteries are occluded, leading to increase pulmonary blood vessel resistance. Ultimately the resistance in the lungs may exceed the resistance in the arteries of the rest of the body, which leads to a reversal of flow from left-to-right to right-to-left shunt.

The reversal of the shunt leads to cyanosis, as well as shortness of breath, coughing up blood, reduced exercise tolerance, syncope (fainting), palpitations, and atrial fibrillation (see figures 15A, 15B). Brain events such paradoxical embolus, thrombosis (stroke) and hemorrhage may occur. Heart failure suggest a poor prognosis, and sudden death is possible.

Digital swelling (clubbing) may occur. Heart murmurs may occur .

EKG may show RVH and atrial arrhythmias (see figures 2, 3a, 5a, 5b, 14, 15a, 15b).

Echocardiogram shows RV pressure overload, pulmonary high blood pressure, and the underlying heart defect. Using intravenous contrast injections along with echocardiogram will visualize the intracardiac defect.Heart catherterization is necessary to assess the lung hypertension and the size of the defect.

Rate of survival is 80% 10 years after diagnosis, 77% at 15 years, and 42% at 25 years. Death is usually sudden, presumably due to arrhythmias, but some die of the above mentioned complications.

Lung transplantation with repair of the cardiac or combined heart-lung transplantation is an option for patients with a poor prognosis (failing to respond to medical therapy).

Brickner,M.E. and others,Congenital Heart Disease in Adults,N.Engl.J.Med.,Vol.342.N4,2000,pp.334-342

 

Anomalies of the Great Veins

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Introduction
Anomalies of the Systemic Veins
Anomalies of the Pulmonary Veins
Anomalies of the Coronary Sinus

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Introduction
In the normal heart, the superior and inferior vena cavea, along with the coronary sinus, have a characteristic arrangement within the right atrium. It is therefore appropriate to consider abnormalities of each channel separately, recognizing that, in rare cases, these anomalies may coexist.

Anomalies of the systemic veins are not uncommon, examples of which include a persistent left superior vena cava connected to the coronary sinus, interrupted inferior vena cava, and absent right superior vena cava.

Anomalies of the systemic veins are associated with atrial isomerism, an understanding of which is important in sorting out the various lesions involved. These so-called heterotaxic syndromes are characterized by failure of many "right-left" differentiation, leading to ambiguity in viscero-atrial situs, along with anomalies of systemic or pulmonary venous return.

In patients with left atrial isomerism, the infrahepatic portion of the inferior vena cava is frequently absent, and the venous return from the lower part of the body enters the superior vena cava via the azygos vein. In patients with right atrial isomerism, the right and left hepatic veins may enter the ipsilateral sides of the common atrium, remaining separate from the inferior vena caval entrance.

Abnormalities of the pulmonary veins are also common in both left and right atrial isomerism; direct connection to the superior or inferior vena cava is more frequent in right atrial isomerism, whereas anomalous pulmonary venous drainage into the same side of the atrium as the systemic venous drainage is more frequent in left atrial isomerism. Frequently there is outflow obstruction to pulmonary arterial blood flow at either the valvar or subvalvar level. Pulmonary atresia is more common with right atrial isomerism, whereas pulmonary stenosis is more common in left atrial isomerism. Pulmonary artery anomalies are not rare, particularly when there is pulmonary atresia with the ductus arteriosus as the only source of pulmonary blood flow. After the ductus closes, a "coarctation" commonly develops in the pulmonary artery just at the insertion of the ductus. The branching pattern of the pulmonary arteries generally assumes one of two forms, depending on whether left or right atrial isomerism is present.

In right atrial isomerism, both right and left pulmonary arteries tend to look like a normal right pulmonary artery, with the bronchus for the upper lobe being above the first segmental artery for the right upper lobe (eparterial bronchus).

In contrast, in left atrial isomerism, the bronchi are below the pulmonary artery at the hilum (hyparterial bronchi), as is the case for a normal left pulmonary artery. In right atrial isomerism, both lungs tend to be trilobed, whereas in left atrial isomerism both lungs tend to be bilobed.

Finally, asplenia is more commonly present in right atrial isomerism, whereas polysplenia is more frequently associated with left atrial isomerism. These features have contributed to the general rule (which has many exceptions) that patients with right atrial isomerism tend to have bilateral "right-sidedness", whereas those with left atrial isomerism tend to have bilateral "left-sidedness".

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Anomalies of the Systemic Veins

This discussion in limited to anomalies of the great systemic veins, which include the superior and inferior vena cava, along with the coronary sinus.

Anomalies of the superior vena cava

A persistent left superior vena cava is the most common form of anomalous venous drainage involving the superior vena cava and represents persistence of the left horn of the embryonic sinus venosus, which normally involutes during normal development to become the coronary sinus. Almost always, a persistent left superior vena cava enters the right atrium through the orifice of an enlarged coronary sinus. To this extent, therefore, the lesion is considered to be an anomaly of the coronary sinus. It characteristically reaches the heart in the angle between the left atrial appendage and the left pulmonary veins. The left superior vena cava then runs down the back of the left atrium to enter the left atrioventricular groove and channel draining blood from the head and both arms. This is the site in the normal heart of the oblique ligament and vein of Marshall.

A persistent left superior vena cava is of no clinical significance since the systemic venous blood continues to return to the right atrium, but may be troublesome in keeping blood out of the field during cardiopulmonary bypass. It may be ligated only in the presence of a communicating vein between the right and left superior vena cavea. In some circumstances, the left vena cava may be the only channel draining the head and both arms, and the usual right superior vena cava is absent.

Rarely, a persistent left superior vena cava can be connected to the roof of the left atrium between the left atrial appendage and pulmonary veins rather than to the coronary sinus. This anomaly is termed complete unroofing of the coronary sinus. The orifice of the coronary sinus then persists as an interatrial communication. A levo-atrial cardinal vein is a rare venous structure that is found in association with the hypoplastic left heart syndrome. It provides the only route of exit for pulmonary venous return, and typically runs along the roof of the left atrium, from the anticipated site of a left superior vena cava, to the left brachiocephalic vein, and the superior vena cava.

Other rare anomalies of the superior vena cava include a right superior vena cava connected to left atrium, and a right superior vena cava connecting with both the right and left atria through separate orifices in the presence of an intact atrial septum. Aneurysmal dilatation of the superior vena cava is recognized as being an acquired lesion of the heart and is rarely seen in children.

Anomalies of the inferior vena cava

Anomalies of the inferior vena cava are most commonly an integral constituent of atrial isomerism, and only rarely is found in patients with usual or mirror-image atrial arrangements. The most common lesion of the inferior vena cava is that of interruption of the abdominal portion, with continuation through either the azygos or the hemiazygos veins. Described simply as ‘azygos continuation’, it is important to always exclude the existence of left atrial isomerism, which is performed through the identification of the bronchial morphology and determination of the presence of polysplenia. When there is interruption of the inferior vena cava with azygos continuation, all the systemic venous return reaches the morphologically right atrium through a superior vena cava. With azygos continuation, this is the right-sided vein, whereas with hemiazygos continuation, the inferior caval blood is returned through a persistent left superior vena cava.

Anomalies of the coronary sinus

Morphology
The most frequent morphological anomaly of the coronary sinus is persistence of a left superior vena cava which drains through the orifice of the coronary sinus. Under these circumstances, the coronary sinus is enlarged, and the lesion is of no clinical importance. An unroofed coronary sinus, however, can produce windows into the left atrium and provide right-to-left intraatrial shunting. The extreme form of this lesion is completely unroofed coronary sinus, in which the interatrial communication is at the mouth of the sinus. Isolated coronary sinus windows can occur, however, when there is no persistent left superior vena cava and when the atrial septum is intact.

Other rare reported anomalies of the coronary sinus include connection of hepatic veins to the coronary sinus, fistulous connections between the coronary sinus and the coronary arteries, and connection of the coronary sinus to the inferior vena cava.

The unroofed coronary sinus syndrome consists of total absence of the coronary sinus, as there is absence of the partition between the coronary sinus and the left atrium. Individual coronary veins drain separately into both the right and left atria. The unroofed coronary sinus syndrome with persistent left superior vena cava occurs when part or all of the common wall between the coronary sinus and the left atrium is absent, and there is a persistent left superior vena cava. The persistent superior vena cava usually connects to the left upper corner of the left atrium between the attachment of the left atrial appendage and the left pulmonary veins.

There is often an associated coronary sinus ASD, which may be further complicated by a confluent partial or complete atrioventricular septal defect. Other associated lesions include a patent foramen ovale, ostium secundum ASD, tricuspid atresia, tetralogy of Fallot, and atrial isomerism. Of considerable importance is that the innominate vein is absent in the great majority of cases, and the right superior vena cava is frequently small or absent. The inferior vena cava may cross to the left side below the diaphragm and enters the left hemiazygos vein, which subsequently drains into the left superior vena cava. The hepatic veins usually enter the inferior aspect of the right atrium, but they too may connect anomalously to the inferior left atrial wall.

Hemodynamics
Isolated completely unroofed coronary sinus is associated with a small right-to-left shunt and is usually of no hemodynamic consequence. In the presence of a persistent left superior vena cava, however, cyanosis may be mild or severe depending on the degree of right-to-left shunting.

Clinical Findings & Management

Patients with completely unroofed coronary sinus and persistent left superior vena cava present with cyanosis. Cerebral embolization and cerebral abscess may also complicate the clinical picture. The diagnosis of unroofed coronary sinus syndrome is usually made by echocardiography. Cineangiography may be useful in defining a persistent left superior vena cava and/or inferior vena cava drainage to the left atrium, in addition to defining commonly associated abnormalities.

Medical management is usually expectant, and operative correction is usually indicated.

Isolated coronary sinus ASD (isolated unroofed coronary sinus without persistent left superior vena cava) is treated the same as other types of ASD. Unroofed coronary sinus with persistent left superior vena cava is approached with the goal of separating the systemic from pulmonary venous drainage. The most direct method is to resect much of the atrial septum, leaving a rim of limbus to preserve the conduction system, then separate the three systemic veins from the four pulmonary veins by means of a pericardial patch. Left superior vena cava ligation can be safely done if there is a patent crossing vein connecting the right and left superior vena cavea. A final alternative is to anastomose the left superior vena cava directly to the left pulmonary artery, although the experience with this method is limited. When unroofed coronary sinus is associated with other major cardiac anomalies, the associated anomaly usually presents a clear indication for operation.

RIGHT VENTRICULAR HYPERTROPHY IN CONGENITAL HEART DISEASE AND DIFFERENTIAL

Some of the causes of right ventricular hypertrophy include congenital heart disease(there are acquired causes as well:see below) such as the following:

A.Triology of Fallot
Triology of Fallot is composed of:

1. Pulmonary artery stenosis (valvular)

2. Right ventricular hypertrophy(increased thickness of the right ventricular walls)

3. Atrial septal defect(hole in the atrial septum).

Diagnosis can be established by

Doppler echocardiography.

DD of congenital heart diseases related to right ventricular hypertrophy

A. Cyanotic heart disease(in which the patient has a bluish discoloration due to decreased oxygen leve from shunting of desaturated blood from the right side of the heart to the leftl through anabnormal hole inthe the heart or its great vessels)):
1. with right ventricular hypertrophy: Tetralogy of Fallot with pulmonary stenosis(narrowing of the opening of the great vessel carrying unoxygenated blood to the lungs from the right ventricle),ventricular septal defect(hole in the lower partition separating the right ventricle from the left,"IVS") ,over-riding of the aorta (the great vessel leading out of the heart carrying the oxygenated blood over the interventricular septum("IVS")to the rest of the body from the left ventricle); Eisenmenger syndrome(see above under cyanotic heaertdisease).

B. Non-cyanotic heart disease:
1. with right ventricular hypertrophy: ASD(hole in the atrial septum), pulmonary stenosis(narrowing of the pulmonary artery,which receives blood from the right ventricle ,sending to it to the lungs for oyxgenation).

Diagnosed by doppler echocardiography,and MRI

Differential diagnosis

The right ventricular hypertrophy(increased thickness of the right ventricle) can be due to congenital or acquired causes like an atrial septal defect(congenital)and mitral stenosis from rheumatic fever fro example.

 

The Abnormal Ventricular Electrocardiogram(ECG)(see figures illustrations 1 and 2)

 

 

 

 

 

Illusration figure 1

 

 

 

 

 

 

ILlustration figure 2

The Mean T Vector and Right Ventricular Hypertrophy

Diastolic pressure(filling period)overload of the right ventricle should theoretically produce a mean T vector that is larger than average, and the ST segment vector should be parallel to the mean T vector.

Actually, the most common cause of diastolic (filling period) overload of the right ventricle is a secundum atrial septal defect(a hole in the upper partition of the heart,the atrium) in which a right ventricular conduction defect dominates the electrocardiogram. The T wave abnormality in such a patient is secondary to the QRS abnormality , and the latter dominates the electrocardiogram rather than abnormalities associated with right ventricular diastolic pressure overload.

Systolic pressure(when the ventriles are squeezig down to contract) overload of the right ventricle, due to congenital heart disease, such as pulmonary valve stenosis, tetralogy of Fallot, or the Eisenmenger syndrome, produces a mean QRS vector that is directed to the right and anteriorly. Therefore, the mean T vector will be located 150° to 180° away from the mean QRS vector and will be directed leftward and posteriorly (Fig. 6.22, figure 1 lnk attached).

The transmyocardial pressure gradient of the right ventricle is decreased and finally eliminated by the abnormal systolic pressure generated during the late stage of mechanical ventricular systole. This permits the repolarization process to begin in the endocardium of the right ventricle, producing electrical forces that are opposite normal (Fig. 6.23 ,fgfure 2attached separately). A right atrial abnormality is often present.

Figure 6.22 (click image to zoom) The difference between the electrocardiographic abnormalities produced by congenital heart disease, such as pulmonary valve stenosis (A), and those produced by the early stages of acquired disease, such as mitral stenosis (B).

A. The duration of the QRS complex is 0.10 second or less. The mean QRS vector is directed to the right and anteriorly, and the ST and T vectors are directed opposite the mean QRS vector. This type of abnormality occurs with congenital disease, such as pulmonary valve stenosis, or advanced acquired disease, such as mitral stenosis with moderately severe pulmonary hypertension. A right atrial abnormality may be apparent in patients with right ventricular hypertension.

B. The duration of the QRS complex is 0.10 second or less, and the mean QRS vector is located vertically and posteriorly. The mean T vector may be directed to the left and slightly posteriorly. This type of mean QRS vector is often caused by acquired disease. A left atrial abnormality as shown here suggests an early stage of mitral stenosis.

Figure 6.23 (click image to zoom) Hypothetical explanation for the electrocardiographic abnormalities caused by systolic pressure overload of the right ventricle.
A. Electrical forces and QRS and T deflections of a hypothetical cell that has been stimulated on the left side.

B. Electrical forces and QRS and T deflections produced when a hypothetical cell has been cooled but also stimulated on the left side.

C. Normal depolarization and repolarization of the ventricular wall of a normal adult. The endocardial systolic pressure is greatest in the endocardial area as compared to the epicardial area. Both the QRS complex and T wave are upright.

D. Systolic pressure overload of the right ventricle. The systolic pressure is so great that there is no significant difference between the endocardial and epicardial pressure. The QRS vector will be directed to the right and the mean T vector will be directed to the left.

Early in the natural history of right ventricular hypertrophy due to acquired heart disease, such as mitral stenosis or primary pulmonary hypertension, the mean QRS vector tends to have an intermediate or vertical direction; it usually retains a slightly posterior direction. The mean T vector tends to be directed leftward and posteriorly (Fig. 6.22 figure 1 illustratio). A left atrial abnormality may be present with mitral stenosis, and a right atrial abnormality may occur with pulmonary hypertension.

Later in the course of disease, as more severe right ventricular hypertension develops, the mean QRS vector tends to be directed more to the right and anteriorly, and the mean T vector eventually lies 150° to 180° away from the mean QRS vector, being directed to the left and posteriorly. The mean ST vector tends to be parallel with the mean T vector.