heart author" faq
Bypass Surgery

This type of surgery with reference to the heart involves harvesting veins taken from the periphery (especially the legs) and subsequently utilized to bypass significant atherosclerotic plaque blockages of coronary arteries (see figures 121a and 121b). This type of surgery of the internal mammary arteries are also used to bypass the blockages.

The major complications after coronary artery surgery are bleeding requiring reoperation, myocardial infarction, stroke ,respiratory distress wound infection and renal failure. Patients who experience one or more complications have an eight to ten times greater probability of mortality comport with those who sustain no complications . Length of hospital stay and costs are affected by most of these major complications. Important predictors of morbidity include previous cardiac surgery, emergency operation, advanced age, peripheral vascular disease, and preoperative elevated serum creatinine. These indicators affect myocardial and respiratory status but do not predict bleeding or wound infection with the same accuracy.


The propensity for bleeding is multifactorial,but relates to advanced age ,use of antiplatelet type drugs preoperatively, prolonged operating time, previous cardiac surgery , and less frequently, preoperative coagulopathy. Aspirin taken within a week to ten days after coronary bypass surgery has been associated with an increased rate of bleeding, increased use of blood and blood products, and longer intensive care unit hospitalization. Newer products such as fibrin glue and aprotinin are reported to decrease postoperative bleeding. The routine use of preoperative tests in accessing bleeding risk is not justified. Need for transfusions relates to body surface area, preoperative anemia ,and advanced age more than any other factors.Erythropoietin has been used to increase red blood cell production after autologous blood donation ;however, its role in postoperative anemia is not yet defined.

Myocardial Infarction

In elective coronary bypass surgery the transmural .myocardial infarction rate is approximately two% The rate of preoperative myocardial infarction is less in low risk patients and greater in high risk patients, i.e., reoperations and coronary arterial operations combined with other cardiac surgery. The rate of myocardial infarction has declined in each decade from the nineteen seventies to the nineteen nineties, presumably because of better myocardial protection. The large Q wave infarctions seen in the early days of coronary bypass surgery are infrequent today. Transient abnormal Q. waves may occur as a result of alterations in ventricular depolarization or maybe unmassed by improved function of a contiguous ventricular segment. Patients who experience nonfatal perioperative myocardial damage have essentially the same intermediate- term course as patients without the myocardial infarction. The exceptions are those who require intraaortic balloon pumping for ischemia/infarction postoperatively. although postoperative intraaortic balloon pumping is required and only one to two percent of the elective surgeries today, most studies have shown that the requirement for balloon pumping portends the lower survival rate because these patients tend to have complicated preoperative infarctions.


The mechanism of stroke after cardiac surgery including embolization, hypoperfusion or inflammatory responses stimulated byextracorporeal circulation. Ascending aortic atherosclerosis is a major contributor to brain damage and myocardial complications. Aortic disease is to be suspected in patients with diffuse brachiocephalic disease, documented peripheral vascular disease, or left main coronary artery narrowing and is demonstrated directly by palpable plaquediscovered during cannulation or construction of aortic anastamoses. It has been shown recently that aortic atheroemboli more frequently in patients undergoing coronary artery surgery than other cardiac procedures. Acorrelation between increased incidence of atherembolism, advanced age,and peripheral vascular disease is apparent. The surgeon should anticipate finding aortic atherosclerosisa before entering the aorta. The problem may be circumvented by femoral artery or distal arch cannulation. If atherosclerosis is discovered during the construction of bypass grafts, the ascending aorta should be open and debrided, possibly under deep hypothermia. Obviously signs of aortic atherosclerosis contraindicate aortic cross- clamping. In situ internal thoracic arteries should be used if the subclavian artery is a widely patent. Vein grafts or other arterial conduits may be anastomosed directly to the internal thoracic arteries.

Respiratory distress

Respiratory distress has been related to lengthy operating time; increase number of blood transfusions; increased amount of crystalloid fluid infusion; suboptimal preoperative nutritional status of the patient ;presence of intrinsic pulmonary disease, neuro logical deficit o r phrenic nervedysfunction; and cardiac failure. Congestive heart failure during the operation is the most important risk factor for postoperative pulmonary complications. This complication is relatively infrequent in otherwise uncomplicated patients. Pneumonia may be at related to prolonged intensive care unit stay, presence of chronic obstructive pulmonary disease, administration of gastric acid inhibitor drugs and prolonged mechanical ventilation support and may be prevented by keeping long- term intensive care unit patients in the head -up position to avoid aspiration, providing oral hygiene, frequent sterile suctioning,and use of sucralfate for the stress ulcer prophylaxis rather than antacids or H2 antagonists. The role of selected digestive decontamination is not fully settled.

Wound infections

Sternal wound infection with mediastinitis occurs in approximately one% of elective coronary bypass patients and usually detected around the seventh to ninth postoperative day.In unusual cases this complication may arise several weeks postoperatively.The mortality related to mediastintis is high (14%). Wound infection increase hospital cost more than any other nonfatal complication because of the protracted hospitalization related to chest wall reconstruction .Wound infections are more likely to occur in diabetic patients. Use of the internal thoracic artery is not a risk factor for wound complications except in bilateral usage in diabetic patients Treatment is surgical drainage and by either primary closure or treatment with rotational muscle flaps.

Renal failure

Renalfailure may be the result of underlying renal disease, especially when coupled with cardiac instability postoperatively.Vasopressor use intraaorticen balloon pumping, excessive bleeding, history of chronic renal disease, and advanced age are predictors of postoperative renal failure. Some studies have supported the use of low dose dopamine to increase renal blood flow as a protective measure.

Abdominal complications

Though rare, the most common abdominal complication is gastrointestinal hemorrhage due to esophagitis o rgastritis.Pancreatitis is correlated with low cardiac output and multisystem complications. Patients who have the history oof pancreatititis and suffer complications postoperatively may be prone to recurring pancreatitis .

Atrial fibrillation

Atrial fibrillation may be a source of emboli postoperatively. Advanced age is related to atrial dysrhythmias.The incident of atrial fibrillation varies from a low of four percent in patients less than 40 years of age to more than 50 percent in patients more than 75 yearsold. The risk of incurring new atrial fibrillation appears to be independent of advanced coronary atherosclerosis or even left ventricular function .The number of factors such as beta blocker withdrawal ,lenghty operation and post cardiotomy syndrome have been implicated but none herald atrial fibrillation consistently. Electrical conversion to normal sinus rhythm may cause embolization,and prophylactic oral anticoagulation has been advocated.

Other complications

Other infrequent complications include brachial plexus injuries, whichmay be related to spreading the sternum and compressing the plexus between the clavicle and the firsr rib with resultant transient median nerve trauma Pulmonary embolism is rareLower extremity wound complications are unusual but cellulitis may occur in diabetic patients with poor circulation.

In the first few months after hospital discharge the clinician should be vigilant for pericarditis/pleuritis, wound infections, a triall arrhythmias, epatitis and recurrent angina. Pulmonary embolism is rarel but should be suspected in those who have a protracted hospital course or who have a history of pulmonary embolism or phlebitis.


Return to work is a complicated subject.Since the median age of coronary bypass patients is approaching 65 years and is older in many communities, return to full activity may be a more realistic expectation. Nonetheless, factors affecting return to work include the status of employment preoperatively, age, income, gender, self employment, whether white collar or blue collar, college education,relief of symptoms, and preoperative left ventricular function. It is known that the longer the unemployment preoperatively, the less likely the return to full employment. Other factors that adversely affect future employment include comorbidity, physician advice, and disability compensation. It is advised that the patient consult with his cardiologist and consider a stress ECG test to determine his ability to run on the treadmill without symptoms and ischemia, and compare the lifting of heavy boxes, stair climbing etc to the stress on the treadmill to gain an insight as to whether the patient can do the preoperative job safely without symptoms or ischemia.