PERIPHERAL VASCULAR DISEASE (PERIPHERAL ARTERIAL DISEASE; PAD; ARTERIOSCLEROSIS OBLITERANS)

Arteriosclerosis of the extremities is a disease of the blood vessels characterized by narrowing and hardening of the arteries (see Fig.70 under atherosclerosis of coronary arteries ) that supply the legs and feet (Fig.1: leg arteries). This causes a decrease in blood flow that can injure nerves and other tissues.

Fig.1: Leg arteries

Causes, incidence, and risk factors

Arteriosclerosis, or "hardening of the arteries," commonly shows its effects first in the legs and feet. The narrowing of the arteries may progress to total closure (occlusion) of the vessel. The vessel walls become less elastic and cannot dilate to allow greater blood flow when needed (such as during exercise). Calcium deposits in the walls of the arteries contribute to the narrowing and stiffness. The effects of these deposits may be seen on ordinary X-rays and on angiograms (see Fig.53 under coronary atherosclerosis).

This is a common disorder, usually affecting men over 50 years old. People are at higher risk if they have a personal or family history of coronary artery disease (heart disease) or cerebrovascular disease (stroke) (see Fig4:Cerebrovascpad below), diabetes, smoking, hypertension, or kidney disease involving hemodialysis.

Fig4: Cerebrovascpad Cerebrovascular disease is atherosclerosis that occurs in the blood vessels supplying blood to the brain. Most cerebrovascular disease occurs within arteries not in the brain itself, but in the neck (carotid arteries), supplying oxygen-rich blood to the brain. Atherosclerosis occurring within these neck arteries is a form of peripheral arterial disease (PAD) called carotid artery disease. Carotid artery disease accounts for well over 95 percent of symptom causing cerebrovascular disease.

Symptoms

Often, symptoms affect one limb. If arteriosclerosis exists in both limbs, the intensity is usually different in each.
Leg pain (intermittent claudication) occurs with exercise (such as walking),relieved with rest.
Numbness of the legs or feet at rest
Cold legs or feet
Muscle pain in the thighs, calves, or feet
Loss of hair on the legs and/or feet
Change of color of the legs
Paleness or blueness (cyanosis)
Pulse, weak or absent in the limb
Walking/gait abnormalities

Signs and tests

An examination may show arterial bruits (whooshing sound heard with the stethoscope over the artery), decreased or absent pulse in the extremities, or decreased blood pressure in the affected limb.

Blood tests may show high cholesterol.

Peripheral artery disease may be revealed by:

An abnormal ratio between the blood pressure of the ankle and arm (ankle/brachial index, or ABI).

A doctor suspects an obstruction based on the symptoms the patient describes and a pulse that's diminished or absent below a certain point in the leg. Doctors estimate blood flow to a person's legs in several ways, including comparing blood pressure at the ankle with blood pressure in the arm. Normally, the ankle pressure is at least 90 percent of the arm pressure, but with severe narrowing it may be less than 50 percent.

The first and most important noninvasive test for PAD is the ankle-brachial index (ABI). This test may be performed in the physician's office and has only 4 requirements:

1) basic understanding of how to perform an ABI.
2) basic knowledge of arterial anatomy.
3) handheld continuous-wave Doppler ultrasonic probe and acoustic gel.
4) sphygmomanometer.

The ABI compares the blood pressure obtained with the handheld Doppler in the dorsalis pedis or posterior tibial artery (whichever is higher) with the blood pressure in the higher of the 2 brachial pressures.

In general, an ABI of >/=0.90 is considered normal, >0.40 to <0.90 reflects mild to moderate PAD, and </=0.40 suggests severe arterial occlusive disease.

The ABI has emerged as one of the most potent markers of diffuse atherosclerosis, CV risk, and overall survival in various patient populations; an abnormal ABI indicates a 3-fold CV risk. In a study of 2023 middle-aged men screened with ABI,[4] the relative risks for mortality from all causes, CV causes, and coronary causes were significantly higher among patients with an ABI of >/=0.90 than among patients with a normal ABI. Similarly, in a study of 1492 women >65 years of age,[5] the relative risks for all-cause mortality, heart disease, and CV disease were significantly greater when the baseline ABI was </=0.90. In a study of >5000 men and women >/=65 years of age,[6] results showed that the lower the ABI, the greater the incidence of CV risk factors and clinical CV disease.

Limitations of the ABI include:

1) A normal ABI in the face of abnormal peripheral arterial circulation (ie, a false-negative result). In elderly patients or patients with end-stage renal disease or, more commonly, diabetes mellitus, the ankle arteries may have calcification in the medial layer. Therefore, when the physician compresses the sphygmomanometer and listens with the Doppler probe, the Doppler signal does not disappear at a pressure of >/=250 mm Hg. This reading does not translate into a normal ABI but instead indicates vessel calcification, and more sophisticated noninvasive tests are required.

2) A normal ABI in patients with classic symptoms suggesting intermittent claudication and PAD. Patients with moderate disease of the infrarenal aorta or iliac arteries may have normal arterial circulation at rest but when exercised demonstrate a decrease in ankle pressure. Therefore, a resting study is inadequate for patients with exertional symptoms of intermittent claudication. In this situation, an exercise arterial study should be performed to determine the true etiology of exertional limb pain.

The diagnosis may be confirmed by certain tests:

Segmental Limb Pressures and Pulse-Volume Recordings

Once the ABI has been performed, which provides objective evidence of the presence and overall severity of PAD in a limb, more specific information can be obtained in the vascular laboratory. In the laboratory, segmental limb pressure measurement can aid in localizing stenoses or occlusions. Limb pressure cuffs are placed on the thigh (some laboratories prefer high- and low-thigh cuffs), calf, ankle, transmetatarsal region of the foot, and digit. The ABI is calculated and then the pressure is inflated sequentially in each cuff to ~20 to 30 mm Hg above systolic pressure. With a continuous-wave Doppler probe placed at a pedal vessel, the pressure in the cuff is released gradually, and the pressure at each segment is measured. A decrease in pressure between 2 consecutive levels of >30 mm Hg suggests arterial occlusive disease of the artery proximal to the cuff. In comparing the 2 limbs, a 20- to 30-mm Hg discrepancy from one limb to the other at the same cuff level also suggests a significant arterial stenosis or occlusion proximal to the cuff.

Pulse-volume recordings (PVRs) are plethysmographic tracings that detect changes in the volume of blood flowing through a limb. Using equipment similar to the segmental limb pressure technique, pressure cuffs are inflated to 65 mm Hg, and a plethysmographic tracing is recorded at various levels. A normal PVR is similar to a normal arterial pulse wave tracing and consists of a rapid systolic upstroke and a rapid downstroke with a prominent dicrotic notch. With increasing severity of PAD, the waveforms become more attenuated with a wide downslope and, ultimately, virtually absent waveforms (peripheralart- Figure5).

Figure5: Peripheralart Pulse-volume recording waveforms.

 

The ABI, segmental limb pressure measurement, and PVRs (periheral art-Figures 6 and 7) are useful noninvasive tests for evaluating patients with suspected PAD or limb discomfort without an obvious cause. These tests are inexpensive, painless, and reproducible, and the equipment required to perform them is significantly less expensive than modern color-flow duplex ultrasonography.

Figure 6: A normal arterial study with the patient at rest. Note the right ankle-brachial index is 1.28 and the left 1.31. The segmental limb pressures and pulse-volume recordings are normal in both limbs

Figure 7: An abnormal arterial study. The right ankle-brachial index is 0.73 and the left 0.65. The segmental limb pressures and pulse-volume recordings suggest evidence of superficial femoral and/or popliteal artery disease in both lower limbs at rest.

Graded-Exercise Treadmill Test
Segmental limb pressure measurement and PVRs are often combined with a graded exercise treadmill test. Once the resting pressures and PVRs are obtained, the patient is asked to walk on a treadmill at a constant speed, either at a constant grade (2 mph, 12% incline) or with a variable incline (0% at start, increased by 3.5% every 2 to 3 minutes). The former method exercises patients to a maximum of 5 minutes, whereas the latter continues for a maximum of an 18% incline. The treadmill test:

1) Confirms the diagnosis of intermittent claudication and PAD.

2) Demonstrates objective functional limitation of PAD.

3) Documents the effect of therapy on initial and absolute claudicating distances.

4) Uncovers previously unrecognized coronary artery disease.

Doppler ultrasound examination of an extremity

With Doppler ultrasound, a probe is placed on the person's skin over the obstruction, and the sound of the blood flow indicates the degree of obstruction. A more sophisticated ultrasound technique, color Doppler produces a picture of the artery that shows different flow rates in different colors. Because it doesn't require an injection, it's used instead of angiography whenever possible.

Native vessel arterial duplex ultrasonography is generally accepted as a precise method for defining arterial stenoses or occlusions. The sensitivities of duplex ultrasonography in detecting occlusions and stenoses have been reported to be 95% and 92%, respectively, with specificities of 99% and 97%, respectively.[9] Limitations include tandem (sequential) stenoses, tibial vessel imaging, and difficulty in imaging the inflow arteries.
Imaging of the supra- and infrainguinal arteries can be performed with a 5.0- to 7.5-MHz transducer. The vessels are studied in the sagittal plane, and Doppler velocities are obtained using a 60° Doppler angle. Vessels are classified into 1 of 5 categories: normal, 1% to 19% stenosis, 20% to 49% stenosis, 50% to 99% stenosis, and occlusion. The categories are determined by alterations in the Doppler waveform as well as increasing peak systolic velocities (PSVs). For a stenosis to be classified as 50% to 99%, for example, the PSV must increase by 100% compared with the normal segment of artery proximal to the stenosis. In lower extremity arteries undergoing duplex ultrasonography, systolic velocity ratios generally predict degrees of stenosis (Table). An increase in PSV occurs as a result of increased flow across an arterial stenosis.

Table. Interpretation of Arterial Duplex Ultrasonography

PSV*	Stenosis Severity
Triphasic <100 cm/s	Normal
>30% increase in PSV	20% to 49%
Doubling of PSV( greater than 100% relative to the adjacent proximal segment and reduced systolic velocity distal to the stenosis)	50% to 99%
No Doppler flow in artery	Occluded

*Compared with normal arterial segment proximal to stenosis. PSV = peak systolic velocity.

The same principle is illustrated below in Table 1 from (Stroke. 2007;38:2887.)
© 2007 American Heart Association, Inc. , Progression of Carotid Stenosis Detected by Duplex Ultrasonography Predicts Adverse Outcomes in Cardiovascular High-Risk Patients by Schila Sabeti, MD ; Oliver Schlager, MD ; Markus Exner, MD ; Wolfgang Mlekusch, MD ; Jasmin Amighi, MD ; Petra Dick, MD ; Gerald Maurer, MD ; Kurt Huber, MD ; Renate Koppensteiner, MD ; Oswald Wagner, MD ; Erich Minar, MD Martin Schillinger, MD

Table 1. Criteria for Quantification of the Degree of Carotid Stenosis by Duplex Ultrasound

	0% to 29%	30% to 49%	50% to 69%	70% to 89%	90% to 99%	100%
PSVICA/PSVCCA	<1.4 >4.0	1.5 to 1.9	2.0 to 3.9	>4.0	Trickle flow	No flow
PSVICA	<120	120 to 149	150 to 249	>250
PSV indicates peak systolic velocity; ICA, internal carotid artery; and CCA, common carotid artery. Flow velocities are given in cm/s.

 

Classification of ICA Stenosis

Class	Diameter Stenosis (Category)	Peak Systolic Velocity cm/sec	Peak Diastolic Velocity cm/sec	Systolic Velocity Ratio VICA/VCCA	Flow Characteristics
A	0% (Nl)	<125 cm/sec	<45 cm/sec	<1.8	Minimal or no spectral broadening during the decaleration phase of systole. Boundary layer separation within the carotid bulb is usually present.
B	1-15% (mild)	<125 cm/sec	<45 cm/sec	<1.8	Minimal spectral broadening during the deceleration phase of systole.
C	16-49% (mild to moderate)	<125 cm/sec	<45 cm/sec	<1.8	Increased spectral broadening during systole until the whole systolic window is filled.
D	50-79%	>125-325 cm/sec	>45 cm/sec	1.8-4.0	Marked spectral broadening with a doubling of the systolic velocity with post-stenotic flow ( turbulence and systolic reversal of flow).
Medicare	70-89%	>325 cm/sec		>4.0	91% sensitivity and 87% specifity. NASCET study and Medicare criteria.
D+	80-99%	>125 cm/sec	>140 cm/sec	>4.0	Marked spectral broadening.
E	Total occlusion	N/A	N/A	N/A	No flow signal in an adequately visualized ICA (especially distal) with characteristic low or reversed diastolic component in the CCA. A characteristic "thump" may be noted at the stump, or origin of the occlusion.

Arterial duplex ultrasonography has been used to guide the percutaneous interventionist toward the appropriate access site to facilitate endovascular therapy. This technology also has been used after endovascular therapy to determine the technical success and durability of the procedure (peripheralart-Figure 8). However, data indicate that duplex ultrasonography performed too soon after balloon angioplasty may overestimate residual stenosis, which may limit the value of this technology.

Figure 8: peripheralart Duplex sonogram of left external iliac artery stent.

Graft Surveillance
In many patients who have undergone surgical bypass graft revascularization, particularly with saphenous vein, stenoses will develop, which increase the risk for graft failure. For grafts that have formed a thrombosis, secondary patency rates are dismal. If the stenosis is detected and repaired prior to graft thrombosis, an estimated 80% of grafts will be salvaged. Therefore, a well-organized graft surveillance program is crucial in preserving patency of the bypass graft. In 1 series of 170 saphenous vein bypass grafts, 110 stenoses were detected over a 39-month period. Among grafts that underwent surgical revision once a stenosis was detected, the 4-year patency rate was 88%, whereas among grafts that did not undergo revision despite the detection of a stenosis, the 4-year patency rate was 57%. The use of an intensive surveillance program has been less beneficial for patients receiving prosthetic grafts.
The procedure for graft surveillance is similar to native vessel arterial duplex ultrasonography. The inflow artery to the bypass graft is initially imaged using a 5.0- to 7.5-MHz transducer and a Doppler angle of 60°. Then, the proximal anastomosis; proximal, mid-, and distal graft; distal anastomosis; and outflow artery are interrogated. The PSV and end-diastolic velocity are obtained at each segment and compared with those of the segment of graft proximal to the area being studied. If the ratio of the PSV within a stenotic segment relative to the normal segment proximal to the stenosis is >2, this suggests a 50% to 75% diameter reduction. The addition of end-diastolic velocities of >100 cm/s suggests >75% stenosis.

Vein bypass grafts should be studied within 7 days of formation and again in 1 month, and surveillance should be repeated at 3-month intervals during the first year. If the graft remains normal after the first year, follow-up surveillance should be done every 6 months thereafter. Ankle pressures and waveforms should be obtained at the time of each surveillance study. The development of a stenosis during a surveillance examination should prompt consideration of arteriography, either with contrast or magnetic resonance technology.

Algorithms For Pad Testing
Although vascular laboratories use different algorithms for diagnosing PAD, some consistent patterns have emerged. ABIs should be performed on every patient suspected of having PAD. If specific information regarding the precise location of arterial stenoses or occlusions is required, complete duplex ultrasonography should be performed from the infrarenal abdominal aorta through the tibial arteries. The limitations of this approach include prolonged examination time, additional cost, and difficulty in interpreting sequential or tandem lesion severity distal to a significant proximal stenosis.
If general information regarding the location of arterial occlusive disease is required, physiologic testing with segmental limb pressures and PVRs is sufficient; however, these studies must be performed with the patient both at rest and with exercise. The exercise portion of the examination confirms whether the limb pain is due to vascular or nonvascular ("pseudoclaudication") causes. Pseudoclaudication is usually neurogenic, with a number of possible causes from lumbar canal stenosis to degenerative disk disease of the lumbosacral spine. It may be difficult for the physician to distinguish between symptoms of claudication and pseudoclaudication based on the history and physical examination alone. Specific testing will therefore aid in the diagnosis. Clinical differences in PAD include variable onset of limb pain with exercise, symptoms at rest and with exertion, and the need to sit for relief of pain. Exercise testing also provides objective documentation of the true functional limitation of PAD and can be used to demonstrate physiologic improvement after intervention.

Duplex ultrasonography is helpful in identifying areas of vascular trauma, specifically iatrogenic ones. Pseudoaneurysms occur in </=7.5% of femoral artery catheterizations and can result in significant complications, including distal embolization into the native arterial system, expansion, extrinsic compression on neurovascular structures, rupture, and hemorrhage. Duplex ultrasonography can identify these lesions rapidly and accurately, and the use of direct ultrasound-guided compression or ultrasound-guided thrombin injection can repair the lesions without the need for invasive surgical procedures.

Peripheralart-fig10. Lower-extremity atherosclerotic arterial disease. Gray-scale sonogram demonstrates the popliteal artery, which is located between the calipers. It measures 0.62 cm in diameter. Findings are normal in this study.

Peripheralart-fig11:Lower-extremity atherosclerotic arterial disease. Color Doppler sonogram of the popliteal artery (same patient as in Image peripheralart-fig10). The red color represents arterial blood flow, its direction, and its velocity inside the artery. These data were obtained by measuring the Doppler shifts originating from the sampled volume inside the artery). Findings are normal in this study.

Movie:

Peripheralart-fig12: Lower-extremity atherosclerotic arterial disease. Digital subtraction angiogram (DSA) illustrates a high-grade short-segment stenosis of the lumen of the right superficial femoral artery .

Peripheralart-fig13:Lower-extremity atherosclerotic arterial disease. Conventional catheter angiogram. The inflated angioplasty balloon technique was performed to treat the stenosis in the lumen of the right superficial femoral artery (same patient as in Peripheralart-fig12).

Peripheralartfig14: Lower-extremity atherosclerotic arterial disease. Cut-film angiogram illustrates complete embolic occlusion after angioplasty (a). The occlusion is seen distally at the level of the popliteal artery. The patient was treated with percutaneous catheter suction embolectomy. (Thrombolytic agents such as reteplase or alteplase may also be used.)

Peripheralartfig15 Lower-extremity atherosclerotic arterial disease. Magnetic resonance angiogram (MRA) obtained by using the bolus-chase technique shows the normal anatomy of the lower extremity arterial vasculature, including the aorta (a), the common iliac artery (b), the external iliac artery (c), the internal iliac artery (d), and the common femoral artery (e).

Peripheralart-fig16:Lower-extremity atherosclerotic arterial disease. Magnetic resonance angiogram (MRA) obtained by using the bolus-chase technique shows the normal anatomy of the lower-extremity arterial vasculature, including the deep femoral artery (a) and the superficial femoral artery (b).

Peripheralart-fig17.Lower-extremity atherosclerotic arterial disease. Magnetic resonance angiogram (MRA) obtained by using the bolus-chase technique shows the normal anatomy of the lower-extremity arterial vasculature, including the popliteal artery (a), the anterior tibial artery (b), the tibioperoneal trunk (c), the peroneal artery (d), and the posterior tibial artery (e).

Peripheralart-figPeripheralart-fig18:Lower-extremity atherosclerotic arterial disease. This magnetic resonance angiogram (MRA) of the lower extremities was obtained by using the bolus-chase technique. A short-segment high-grade stenosis is present in the middle of the left superficial femoral artery. Note the collateral arterial supply.

Peripheralart-fig19:Lower-extremity atherosclerotic arterial disease. This magnetic resonance angiogram (MRA) of the lower extremities was obtained by using the bolus-chase technique. Atherosclerotic disease involves the bilateral superficial femoral arteries. Note the multiple lesions, which are primarily in the middle portions, and the large collateral arterial supply. Lower-extremity atherosclerotic arterial disease. This magnetic resonance angiogram (MRA) of the lower extremities was obtained by using the bolus-chase technique. Atherosclerotic disease involves the bilateral superficial femoral arteries. Note the multiple lesions, which are primarily in the middle portions, and the large collateral arterial supply.

Angiography of the arteries in the legs (arteriography) (see peripheralart-fig 9,12,13,14 above;).

Arteriography remains the most accurate and informative test. Arteriography is the criterion standard, but it is considered an invasive diagnostic method. This examination is associated with complications such as hematoma at the puncture site, those due to radiation exposure, intimal flap dissection, or arterial wall rupture, and nephrotoxicity due to the intravenous contrast material (which poses greater risk because of the common association of Lower Extremity Peripheral Arterial Disease with renal arterial disease and renal disease). Therefore, arteriography is preserved for preoperative evaluation only.

In angiography, a solution that's opaque to x-rays is injected into the artery. Then x-rays are taken to show the rate of blood flow, the diameter of the artery, and any obstruction.Angiography may be followed by angioplasty to open up the artery (Peripheralart-fig12; Peripheralart-fig13; Peripheralart-fig22).

Peripheralart-fig9:This angiogram shows a superficial femoral artery occlusion on one side (with reconstitution of the suprageniculate popliteal artery) and superficial femoral artery stenosis on the other side. This is the most common area for peripheral vascular disease.

Peripheralart-fig22:A. Aortogram with pelvic runoff views of a 61-year-old man arterywith left thigh and buttock claudication and common iliac artery occlusion (arrow).B.After recannalization of the totally occluded left common iliac artery(arrow),normal flow was reestablished to the left leg with percutaneous balloon angioplasty and the placement of an iliac stent.

Peripheralart-FIGURE 23: Aortogram demonstrating an isolated left renal artery stenosis in a 71-year-old woman with poorly controlled hypertension and normal renal function. B. Balloon angioplasty produced local dissection with residual stenosis. C and D. After implantation of an AVE stent, full resolution of the hemodynamically significant lesion was achieved. The patient continues to require two medications to control her hypertension.

Intravascular ultrasound (IVUS) of the extremity

An MRI scan

Magnetic resonance angiography (MRA) (see peripheralart-fig.15,16,17,18,19 below) is a test that produces images of arteries and veins with similar accuracy to invasive angiograms but without puncturing the artery to inject dye. MRA is also used to identify small arteries in the lower leg that cannot be seen or detected with angiograms or other testing methods.

MRA is noninvasive and does not require the use of ionizing radiation, and the contrast agent used is relatively non-nephrotoxic. This modality is associated with limitations such as its cost, its availability, the limited depiction of small vessels, its contraindications, and the possible overestimation of the degree of stenosis.

Recently, MRA has emerged as a safe and noninvasive alternative to conventional angiography in the diagnosis of lower-extremity vascular disease. Using MRA studies, a radiologist should be able to detect signs of narrowing (stenosis), dilatation (aneurysm) in the vessel, or a complete interruption of flow, and he or she should be able to compare the results in both legs.

Time-of-Flight (TOF) MRA

Initial reports used 2-dimensional (2D) and 3-dimensional (3D) time-of-flight (TOF) MRA with limited success. These methods rely on the detection of flow-related phenomena to produce angiographic images. Images were degraded by patient motion (primarily due to long scanning times, which may been >1 h). Other causes of poor image quality include turbulence, pulsating arteries, saturation, and poor signal-to-noise ratios (SNRs). However, the TOF is still considered a better technique than contrast-enhanced MRA for evaluating infrapopliteal vessels because MRA depends on blood flow in the immediate vicinity of the region imaged.

Contrast-enhanced 3D MRA has become the method of choice. The technique relies on the detection of contrast enhancement in the vascular lumen to produce findings that are comparable to those of conventional catheter angiography (Peripheralart-fig18; Peripheralart-fig19). The current technique uses the bolus-chasing method material in which vessels are imaged sequentially as contrast flows distally. Multiple overlapping fields of view are used, and images are obtained in the coronal or sagittal planes (usually in 3 coronal stations). This technique also uses subtraction to improve the resultant vascular images by suppressing the background and reducing the volume averaging.

Images demonstrate the contrast-enhanced anatomy of the arterial lumen. Stenosis is depicted as areas of narrowing, and occlusion is depicted as areas of absent signal intensity. Ulceration and aneurysm can also be defined.

Use of bolus-chasing MRA enables radiologists to establish protocols for different studies by adjusting the bolus dose and time, the infusion rate, the region of interest, the section thickness, and the position in the imaging plane by considering the purpose of the study, the patient's condition, and the equipment available.

Bolus-chasing MRA is rapidly evolving for many reasons such as the technology revolution that made equipment widely available, improvements in technical capabilities (eg, increased field strengths, dedicated coils, increased SNRs, decreased repetition times, improved bolus-detection techniques, MR SmartPrep technique). With these changes, along with the increased familiarity and confidence of referring physicians with this new modality, bolus-chasing MRA will replace conventional catheter angiography.

False Positives/Negatives: The value of the study can be increased by using newer magnetic resonance devices with higher resolution, by using gadolinium-based contrast agent, and by having the expertise to interpret the images. However, even when all available resources are used, false-positive and false-negative results may still be encountered, especially in patients who have undergone previous interventions. For example, indwelling stents can cause severe artifacts and may render findings inaccurate or nondiagnostic.

To date, no established data are available; however, multiple studies reveal a sensitivity and specificity of more than 90% with the bolus-chase technique. The rate is slightly better in evaluating the iliac, femoral, and popliteal segments.

Treatment

Treatment focuses on the relief of symptoms and self-care to improve circulation.

Medications may be required to control the disorder, including pain relievers, blood thinners, and medications to enlarge or dilate the affected artery(ies).

Medications often are combined with risk-factor modification and exercise to better relieve symptoms and attempt to delay the progression of the disease.

Medications

Advice: aspirin every day, or to take another platelet inhibitor such as clopidogrel (Plavix). Medications, such as cilostazol (Pletal) and pentoxifylline (Trental), also can help to decrease the symptoms of intermittent claudication.

Surgery is usually performed only on severe cases where the ability to work or pursue essential activities is affected. Surgery may consist of removing the lining of the artery (endarterectomy), or repairing or replacing the vessel (grafting); most commonly, bypass surgery is performed, using a vein or synthetic graft.

SURGERY

Surgery may be required to attempt to treat clogged blood vessels.

Revascularization procedures

The goal of revascularization is to improve circulation, either by opening narrowed arteries or by bypassing the narrowed section of the artery using either a section of vein taken from the leg or a synthetic graft.

These procedures, including surgical and nonsurgical techniques, are used in people who have severe or progressive symptoms, or whose leg pain occurs at rest.

Before revascularization, the location and extent of arterial narrowing is determined by MRI or contrast angiography.

NONSURGICAL PROCEDURES

Balloon Angioplasty

The most common nonsurgical procedure is percutaneous transluminal angioplasty, also called balloon angioplasty (similar technique to that used to open the coronary arteries, but performed on the blood vessels of the affected extremity).This is usually done in the groin but can also be done in the arm. In this procedure, a catheter is inserted into the narrowed artery and a small balloon at the tip is briefly inflated to open the narrowed vessel. This is often accompanied by stent placement, in which a metallic implant is used as a scaffold to widen and support the wall of the artery after it is opened with the balloon.

The two most common types of stents include the following:

Type 1 - Self-expandable stents (eg, Wallstent, peripheralart -fig24)

peripheralart-fig24.A. Carotid angiogram of an asymptomatic, high-grade left internal carotid artery stenosis. B. The lesion is corrected after treatment with balloon angioplasty and the implantation of a Wallstent.

Type 2 - Balloon expandable stents (eg, Palmaz stent) deployed by an angioplasty balloon
All of the published data show that best results are obtained when the disease in common iliac artery, although the outcome is also good when the disease is located in the superficial femoral or popliteal artery.

The field of endovascular surgery is growing rapidly, as are improvement in available instruments and expertise. Currently, atherosclerotic iliac artery stenosis responds well to simple balloon angioplasty, and it has the best results of all of the peripheral vessels. Although many complications and technical failures are still encountered, the excellent results of endoluminal treatment in patients with iliac artery occlusive disease and the relatively low risk for complications (compared with surgical revascularization) ensure an enduring role for this modality. The application of this study in other portions of the vascular tree is still being investigated, but results are promising.

Emboli Protection Devices

The major cause of stroke during carotid endarterectomy and percutaneous carotid intervention is the procedural embolization of plaque debris along with platelet and thrombin aggregates into the cerebral circulation. Transcranial Doppler monitoring, a noninvasive method to detect echogenic microemboli, has demonstrated frequent embolization during carotid endarterectomy and stenting.

Although data are limited, there appears to he a correlation between the number of emboli and neurologic outcome after endarterectomy. Consequently, various mechanical and pharmacologic approaches to prevent distal embolization are currently under investigation to improve the safety of carotid stenting.
Various mechanical devices to prevent embolization are under investigation. Henry et al. reported their experience in 58 carotid artery stent procedures using a prototype cerebral protection device and compared the results to 212 other patients treated without the emboli protection device. This cerebral protection catheter is a low-profile, balloon-tipped device designed to block cerebral emboli when positioned in the internal carotid artery distal to the target lesion. Conceptually, the protection balloon occludes the run-off circulation to the brain, trapping any particles dislodged following balloon angioplasty or stent delivery so that they can subsequently be extracted via aspiration into the guiding catheter. In this series, there was I immediate neurologic complication (0.5 percent) compared to 1 I (5.2 percent) in the group treated without the device. Feasibility of transient carotid occlusion without consequences and potential endothelial injury and embolization from the occlusion balloon itself, however, are important concerns that need further evaluation.

An alternative mechanical embolization device that allows continued perfusion while capturing emboli has been developed (peripheralart-fig25 and 26 figs). This filter-type device has been tested in carotid, coronary, and peripheral interventions and should be available in the near future for rigorous randomized trials.

peripheralart-FIG 25 A. An emboli protection device (Angioguard, Cordis) in closed state. The bold arrow represents 0.014 in. wire that leads the device (4 French)shown by the smaller arrow. B. Open device with a filter with 100 µM pore size. C. Closed filter with captured embolic debris.

Peripheralart-fig26 A. Filter with atheromatous embolic debris. B. Magnified view of typical atheromatous embolic particles retrieved during intervention.

Angioplasty may require only 1 or 2 days in the hospital and may help the person avoid a major operation. The procedure isn't painful but may be somewhat uncomfortable because the person has to lie still on a hard x-ray table. A mild sedative, but not general anesthesia, is given. Afterward, the patient may be given heparin to prevent blood clots from forming in the treated area. Many doctors prefer giving patients a platelet inhibitor such as aspirin to prevent clotting. A doctor can use ultrasound to check on the outcome of the procedure and make sure that the narrowing doesn't recur.

Angioplasty can't be performed if the narrowing is widespread, if it extends for a long distance, or if the artery is severely and extensively hardened. Surgery may be needed if a blood clot forms over the narrowed area, a piece of the clot breaks off and blocks a more distant artery, blood seeps into the lining of the artery causing it to bulge and close off blood flow, or the person has bleeding (usually from heparin given to prevent lotting).

Besides balloons, devices--including lasers, mechanical cutters, ultrasonic catheters, stents, and rotational sanders--are used to relieve obstructions. No one device has proved superior.Endovascular procedures for lower extremity PAD

Ballon Angoiplasty

Stenting.

When angioplasty does not restore an adequate opening for blood to flow through the artery, a stent can be used. A stent is an expandable wire-mesh tube that can be deployed from a catheter at the location of the blockage. The stent can provide ongoing mechanical support to open the vessel and hold the plaque back. The stents currently available are made from a variety of different metals.

Clinical trials with stents that have different medications on them are being performed and have great promise to increase the effectiveness of stents. Stenting in leg arteries is similar to a coronary stenting.

Other catheter-based procedures.

Sometimes the material blocking the artery is mainly clotted blood (a thrombus). In these cases there are a variety of catheters that use water jets to remove the clot as he catheter is passed through it. This is called thrombectomy.

Other catheters are made to deliver drugs that speed the body’s natural ability to dissolve clot. This is called thrombolysis.

There are still other catheters that can remove plaque, called atherectomy catheters. Atherectomy catheters are very rarely used for lower extremity PAD.
Catheter based procedures are often the first method of invasive treatment used for patients with lower extremity PAD. This can usually be done on an outpatient basis and requires only some local anesthetic. Patients can usually return to their normal activity within one to two days. The downside of catheter-based procedures is their relatively high recurrence rates. Most severe disease of the lower extremities extends over long segments of the leg arteries and these long segments often develop new blockages after angioplasty or stenting. For that reason it is important to examine the treated arteries with ultrasound on a regular basis following the treatment so that any recurrence can be detected earlyd treated easily before more extensive surgery or other treatments are required.

Surgery

Surgery very often relieves symptoms, heals ulcers, and prevents amputation. A vascular surgeon can sometimes remove a clot if only a small area is blocked. Alternatively, a surgeon may put in a bypass graft, in which a tube made of a synthetic material or a vein from another part of the body is joined to the obstructed artery above and below the obstruction. Another approach is to remove the blocked or narrowed section and insert a graft in its place. Cutting the nerves near the obstruction (an operation called a sympathectomy) prevents the arteries from having spasms and can be very helpful in some cases.

When amputation is needed to cut out infected tissue, relieve unrelenting pain, or stop worsening gangrene, surgeons remove as little of the leg as possible, particularly if the person plans to wear an artificial limb.

Limbs with gangrene must be amputated to prevent the death of the patient.

Self-care:

Exercise must be balanced with rest. Walking or other activity, performed to the point of pain and alternated with rest periods, is often recommended. Over time, circulation improves because of the development of collateral (new, small) blood vessels.

Stop smoking! Smoking constricts arteries, decreases the blood's ability to carry oxygen and increases the risk of forming clots (thrombi and emboli).

Foot care is particularly important if diabetes is also present. Wear shoes that fit properly. Pay attention to any cuts, scrapes or injury -- the tissues heal slowly when there is decreased circulation and are prone to infection.

If cholesterol is high, change the diet to a low-cholesterol and low-fat diet.

Expectations (prognosis)

The prognosis depends on the underlying disease and the stage at which peripheral vascular disease is discovered. Removal of risk factors, such as smoking, should be done immediately. In many cases, peripheral vascular disease can be treated successfully but coexisting cardiovascular problems may ultimately prove to be fatal.

In most people with peripheral vascular disease, leg symptoms remain stable. About 10 percent to 15 percent of patients improve, and about 15 percent to 20 percent worsen. Prognosis is better for people who are able to remain tobacco-free, stay on a healthy diet, keep their blood cholesterol under control, and exercise regularly

Complications

Injury or infection of the feet and legs
Presence of open sores (ischemic ulcers) on the lower extremities
Ulcers on the feet and toes
Gangrene (tissue death) -- see gas gangrene
Arterial emboli
Impotence

Prevention

Control risk factors such as obesity, high blood pressure, and smoking.

Treatment
If the person is a smoker, they should stop smoking immediately. Exercise is essential to treating this disease. The patient should walk until pain appears, rest until the pain disappears, and then resume walking. The amount of walking a patient can do should increase gradually as the symptoms improve. Ideally, the patient should walk 30-60 minutes per day. Infections in the affected area should be treated promptly.

Peripheral Arterial Disease Of Abdominal Aorta and Its Major Branches

Occlusive arterial disease includes both coronary arteries, which can lead to a heart attack, and peripheral arterial disease, which may affect the abdominal aorta and its major branches (abdominal aortic branches-fig2 and fig.vessels pad-fig3) as well as the arteries of the legs as described above.

Fig.Abdominal aortic branches-fig2

fig.vessels pad-fig3:Various sites which may become involved in arteriosdclerosis.

Other peripheral arterial diseases are Buerger's disease, Raynaud's disease, and acrocyanosis.

Most people with peripheral arterial disease have atherosclerosis, a disease process in which fatty material accumulates under the lining of the arterial wall, gradually narrowing the artery. However, a partial or complete occlusion of an artery can result from other causes, such as a blood clot. When an artery narrows, the parts of the body it serves may not receive enough blood. The resulting decrease in oxygen supply (ischemia) can come on suddenly (acute ischemia) or gradually (chronic ischemia).

To help prevent peripheral arterial disease, a person should reduce the number of risk factors for atherosclerosis, such as smoking, obesity, high blood pressure, and high cholesterol levels.

Diabetes also is a major cause of peripheral arterial disease, and appropriate treatment of diabetes may delay the arterial disease.

Once peripheral arterial disease appears, treatment is directed at its complications--severe leg cramps while walking, angina, abnormal heart rhythms, heart failure, heart attack, stroke, and kidney failure.

Abdominal Aorta and Branches

Obstruction of the abdominal aorta and its major branches may be sudden or gradual. A sudden, complete obstruction usually results when a clot carried by the bloodstream lodges in an artery (embolism), a clot forms (thrombosis) in a narrowed artery, or the artery wall tears (aortic dissection). An obstruction that develops gradually usually results from atherosclerosis; less often, it results from an abnormal growth of muscle in the artery wall or pressure from an expanding mass, such as a tumor, outside the artery.

Symptoms

A sudden, complete obstruction of the superior mesenteric artery, a major branch of the abdominal aorta that supplies a large part of the intestine, is an emergency. A person with such an obstruction becomes seriously ill and has severe abdominal pain. Initially, vomiting and urgent bowel movements usually occur. Although the abdomen may feel tender when a doctor presses on it, the severe abdominal pain is usually worse than the tenderness, which is widespread and vague. The abdomen may be slightly distended. Through a stethoscope, a doctor initially hears fewer bowel sounds than normal in the abdomen. Later, no bowel sounds can be heard. Blood appears in the stool, though at first it can be detected only by laboratory tests. Soon the stool looks bloody. Blood pressure falls, and the person goes into shock as the intestine becomes gangrenous.

A gradual narrowing of the superior mesenteric artery typically causes pain 30 to 60 minutes after eating because digestion requires an increased blood flow to the intestine. The pain is steady, severe, and usually centered on the navel. This pain makes people afraid to eat, and they may lose considerable weight. Because of the reduced blood supply, nutrients may be poorly absorbed into the bloodstream, contributing to the weight loss.

When a clot lodges in one of the renal arteries, the branches that supply the kidneys, a sudden pain occurs in the side, and the urine becomes bloody. Gradual obstruction of the arteries to one or both kidneys usually results from atherosclerosis and may lead to high blood pressure (renovascular hypertension), which accounts for 5 percent of all high blood pressure.

When the lower aorta is abruptly obstructed where it divides into two branches that pass through the pelvis to deliver blood to the legs (iliac arteries), both legs suddenly become painful, pale, and cold. No pulse can be felt in the legs, which may become numb.

When gradual narrowing occurs in the lower aorta or one of the iliac arteries, the person feels muscle tiredness or pain in the buttocks, hips, and calves while walking. In men, impotence is common with narrowing of the lower aorta or both iliac arteries. If the narrowing occurs in the artery that begins at the groin and goes down the leg to the knee (femoral artery), a person typically feels pain in the calves while walking and has weak or no pulses below the obstruction.

Treatment

Whether a person survives a sudden obstruction of the superior mesenteric artery and whether the intestine can be saved depend on how fast the blood supply is restored. To save precious time, a doctor may send a patient for emergency surgery without even taking x-rays. If the superior mesenteric artery is blocked as the doctor suspects, only immediate surgery can restore the blood supply fast enough to save the person's life.

With a gradual obstruction of blood flow to the intestine, nitroglycerin may relieve the abdominal pain, but only surgery can relieve the obstruction. Doctors use Doppler ultrasound and angiography to determine how extensive the obstruction is and whether to operate.

 

Blood clots in the hepatic and splenic arteries, the branches supplying the liver and spleen, generally aren't as dangerous as obstructed blood flow to the intestine. Even though an obstruction can cause injury to parts of the liver or spleen, surgery is rarely needed to correct the problem.

Early surgical removal of a clot from a renal artery may restore kidney function. With a gradual obstruction of a renal artery, doctors can sometimes use angioplasty (a procedure in which a balloon is inserted into the artery and inflated to clear the obstruction), but usually they must remove or bypass the blockage surgically.

Emergency surgery can clear a sudden obstruction of the lower aorta where it divides into two branches to deliver blood to the legs. Sometimes doctors can dissolve the clot by injecting a thrombolytic drug, such as urokinase, but surgery is more likely to be successful.

Arteries of the Legs and Arms(see above)

With a gradually narrowing leg artery, the first symptom is a painful, aching, cramping, or tired feeling in leg muscles during physical activity; this feeling is called intermittent claudication. Muscles hurt when the person walks, and the pain comes on faster and is more severe when the person walks quickly or uphill. Most commonly, the pain is in the calf, but it can also be in the foot, thigh, hip, or buttocks, depending on the location of the narrowing. The pain can be relieved by resting. Usually, after 1 to 5 minutes of sitting or standing, the person can walk the same distance already covered before feeling pain again. The same kind of pain on exertion is also caused by narrowing of the arteries in the arms.

As the disease gets worse, the distance the person can walk without pain gets shorter. Eventually, the muscles may ache even at rest. The pain usually begins in the lower leg or foot, is severe and unrelenting, and gets worse when the leg is elevated. The pain often prevents sleep. For relief, a person may hang the feet over the side of the bed or rest sitting up with the legs hanging down.

A foot with a severely reduced blood supply is usually cold and numb. The skin may be dry and scaly, and the nails and hair may not grow well. As the obstruction worsens, a person may develop sores, typically on the toes or heel and occasionally on the lower leg, especially after an injury. The leg may shrink. A severe obstruction may cause tissue death (gangrene).

With a sudden, complete obstruction of a leg or arm artery, a person feels severe pain, coldness, and numbness. The person's leg or arm is either pale or bluish (cyanotic). No pulse can be felt below the obstruction.

Diagnosis:see above

Treatment
People with intermittent claudication should walk at least 30 minutes a day, if possible. When they feel pain, they should stop until it subsides and then walk again. By doing this, they can usually increase the distance they can walk comfortably, probably because the exercise improves muscle function and makes other blood vessels supplying the muscles grow larger. People with obstructions shouldn't use tobacco in any form. Elevating the head of the bed with 4- to 6-inch blocks may help by increasing blood flow to the legs.

Doctors may prescribe a drug such as pentoxifylline in an effort to improve oxygen delivery to the muscles. Other drugs, such as calcium antagonists or aspirin, also may be helpful. Beta-blockers, which help people with coronary artery obstructions by slowing the heart and reducing its need for oxygen, sometimes worsen symptoms in people with leg artery obstructions.

Performing Foot Care
A person with poor circulation to the feet should use these self-care measures and precautions:

Inspect feet daily for cracks, sores, corns, and calluses.
Wash feet daily in lukewarm water with mild soap and dry them gently and thoroughly.
Use a lubricant, such as lanolin, for dry skin.
Use unmedicated powder to keep the feet dry.
Cut toenails straight across and not too short. (A podiatrist may have to cut the nails.)
Have a podiatrist treat corns or calluses.
Don't use adhesive or harsh chemicals.
Change socks or stockings daily and shoes often.
Don't wear tight garters or stockings with tight elastic tops.
Wear loose wool socks to keep the feet warm.
Don't use hot water bottles or heating pads.
Wear shoes that fit well and have wide toe spaces.
Ask the podiatrist about a prescription for special shoes if the foot is deformed.
Don't wear open shoes or walk barefoot.

Foot Care
The goal of foot care is to protect circulation to the foot and prevent complications of poor circulation. A person with foot ulcers requires meticulous care to prevent further deterioration that would make amputation of the foot necessary. The ulcer must be kept clean: It should be washed daily with mild soap or salt solution and covered with clean, dry dressings. A person with a foot ulcer may need complete bed rest with the head of the bed raised. A person who has diabetes also must control blood sugar levels as well as possible. As a rule, anyone with poor circulation to the feet or with diabetes should have a doctor check any foot ulcer that isn't healing after about 7 days. Many times, a doctor prescribes an antibiotic ointment. If the ulcer becomes infected, the doctor generally prescribes antibiotics to be taken by mouth. Healing may take weeks or even months.

Buerger's Disease
Buerger's disease (thromboangiitis obliterans) is the obstruction of small and medium-sized arteries and veins by inflammation triggered by smoking.

Men ages 20 to 40 who smoke cigarettes get Buerger's disease more than anyone else. Only about 5 percent of people with the disease are women. Although no one knows what causes Buerger's disease, only smokers get it, and continuing to smoke makes it worse. Because only a small number of smokers get Buerger's disease, some people must be more susceptible than others. Why and how cigarette smoke causes the problem aren't known.

Symptoms
Symptoms of reduced blood supply to the arms or legs develop gradually, starting at the fingertips or toes and progressing up the arms or legs, eventually causing gangrene. About 40 percent of people with this disease also have episodes of inflammation in the veins, particularly the superficial veins, and the arteries of the feet or legs. People may feel coldness, numbness, tingling, or burning before their doctor sees any signs. They often have Raynaud's phenomenon (see page 136 in this chapter) and get muscle cramps, usually in the arches of their feet or in their legs but rarely in their hands, arms, or thighs. With more severe obstruction, the pain is worse and lasts longer. Early in the disease, ulcers, gangrene, or both may appear. The hand or foot feels cold, sweats a lot, and turns bluish, probably because the nerves are reacting to severe, persistent pain.

Diagnosis
In more than 50 percent of people with Buerger's disease, the pulse is weak or absent in one or more arteries of the feet or wrists. Often, the affected hands, feet, fingers, or toes become pale when raised above the heart and red when lowered. People may develop skin ulcers and gangrene, usually of one or more fingers or toes.

Ultrasound tests reveal a severe decrease in blood pressure and blood flow in the affected feet, toes, hands, and fingers. Angiograms (x-rays of the arteries) show obstructed arteries and other circulation abnormalities, especially in the hands and feet.

Treatment
A person with this disease must stop smoking, or it will relentlessly worsen, and ultimately an amputation may be necessary. Also, the person should avoid exposure to the cold; injuries from heat, cold, or substances such as iodine or acids used to treat corns and calluses; injuries from poorly fitting shoes or minor surgery (such as trimming calluses); fungal infections; and drugs that can narrow blood vessels.

Walking 15 to 30 minutes twice a day is recommended, except for people with gangrene, sores, or pain at rest; they may need bed rest. People should protect their feet with bandages that have heel pads or with foam-rubber booties. The head of the bed can be raised on 6- to 8-inch blocks so gravity helps blood flow through the arteries. Doctors may prescribe pentoxifylline, calcium antagonists, or platelet inhibitors such as aspirin, especially when the obstruction results from spasm.

For people who quit smoking but still have arterial occlusion, surgeons may improve blood flow by cutting certain nearby nerves to prevent spasm. They seldom perform bypass grafts, because the arteries affected by this disease are too small.

Functional Peripheral Arterial Disorders

Most of these disorders result from a spasm of arteries in the arms or legs. They may be caused by a fault in the blood vessels or by disturbances in the nerves that control the widening and narrowing of arteries (sympathetic nervous system). Such nerve defects may themselves be a consequence of blockage from atherosclerosis.

Raynaud's Disease and Raynaud's Phenomenon
Raynaud's disease and Raynaud's phenomenon are conditions in which small arteries (arterioles), usually in the fingers and toes, go into spasm, causing the skin to become pale or a patchy red to blue.

Doctors use the term Raynaud's disease when no underlying cause is apparent and the term Raynaud's phenomenon when a cause is known. Sometimes, the underlying cause can't be diagnosed at first, but usually it becomes apparent within 2 years.

Between 60 and 90 percent of the cases of Raynaud's disease occur in young women.

Causes

Possible causes include scleroderma, rheumatoid arthritis, atherosclerosis, nerve disorders, decreased thyroid activity, injury, and reactions to certain drugs, such as ergot and methysergide. Some people with Raynaud's phenomenon also have migraine headaches, variant angina, and high blood pressure in their lungs (pulmonary hypertension). These associations suggest that the cause of the arterial spasms may be the same in all these disorders. Anything that stimulates the sympathetic nervous system, such as emotion or exposure to cold, can cause arterial spasms.

Symptoms and Diagnosis

Spasm of small arteries in the fingers and toes comes on quickly, most often triggered by exposure to cold. It may last minutes or hours. The fingers and toes turn white, usually in a spotty fashion. Only one finger or toe or parts of one or more may be affected, turning a patchy red and white. As the episode ends, the affected areas may be pinker than usual or bluish. The fingers or toes usually don't hurt, but numbness, tingling, a pins-and-needles sensation, and a burning sensation are common. Rewarming the hands or feet restores normal color and sensation. However, when people have long-standing Raynaud's phenomenon (especially those with scleroderma), the skin of the fingers or toes may change permanently--appearing smooth, shiny, and tight. Small painful sores may appear on the tips of the fingers or toes.

To distinguish between arterial blockage and arterial spasm, doctors perform laboratory tests before and after someone is exposed to cold.

Treatment
People can control mild Raynaud's disease by protecting their trunk, arms, and legs from cold and by taking mild sedatives. They must stop smoking because nicotine constricts blood vessels. For a few people, relaxation techniques, such as biofeedback, may reduce the spasms. Raynaud's disease is commonly treated with prazosin or nifedipine. Phenoxybenzamine, methyldopa, or pentoxifylline occasionally helps. When people have progressive disability and other treatment doesn't work, sympathetic nerves may be cut to relieve the symptoms, but the relief may last only 1 to 2 years. This operation, called a sympathectomy, generally is more effective for people with Raynaud's disease than for those with Raynaud's phenomenon.

Doctors treat Raynaud's phenomenon by treating the underlying disorder. Phenoxybenzamine may help. Drugs that may constrict blood vessels (such as beta-blockers, clonidine, and ergot preparations) may make Raynaud's phenomenon worse.

Acrocyanosis
Acrocyanosis is a persistent, painless blueness of both hands and, less commonly, the feet, caused by unexplained spasm of the small blood vessels of the skin.

The disorder usually occurs in women, not necessarily those with occlusive arterial disease. The fingers or toes and hands or feet are constantly cold and bluish and sweat profusely; they may swell. Cold temperatures usually intensify the blue coloring, and warming reduces it. The condition isn't painful and doesn't damage the skin.

Doctors diagnose the disorder based on persistent symptoms limited to the person's hands and feet along with normal pulses. Treatment is usually unnecessary. Doctors may prescribe drugs that dilate the arteries, but they usually don't help. Very rarely, sympathetic nerves are cut to relieve symptoms.

REFLEX SYMPATHETHIC DYSTROPHY SYNDROME

Reflex sympathetic dystrophy syndrome (RSDS) is a chronic condition characterized by severe burning pain, pathological changes in bone and skin,excessive sweating, tissue swelling, and extreme sensitivity to touch.

The syndrome is a nerve disorder that occurs at the site of an injury (most often to the arms or legs). It occurs especially after injuries from high-velocity impacts such as those from bullets or shrapnel. However, it may occur without apparent injury.

One visible sign of RSDS near the site of injury is warm, shiny red skin that later becomes cool and bluish.The pain that patients report is out of proportion to the severity of the injury and gets worse, rather than better, over time.

Eventually the joints become stiff from disuse, and the skin, muscles, and bone atrophy. The symptoms of RSDS vary in severity and duration.

The cause of RSDS is unknown. The disorder is unique in that it simultaneously affects the nerves, skin, muscles, blood vessels, and bones.

RSDS can strike at any age but is more common between the ages of 40 and 60, although the number of RSDS cases among adolescents and young adults is increasing.

RSDS is diagnosed primarily through observation of the symptoms. Some physicians use thermography to detect changes in body temperature that are common in RSDS.

X-rays may also show changes in the bone.

Is there any treatment?
Physicians use a variety of drugs to treat RSDS. Elevation of the extremity and physical therapy are also used to treat RSDS. Injection of a local anestheticis usually the first step in treatment. TENS (transcutaneous electrical stimulation), a procedure in which brief pulses of electricity are applied to nerve endings under the skin, has helped some patients in relieving chronic pain. In some cases, surgical or chemical sympathectomy -- interruption of the affected portion of the sympathetic nervous system -- is necessary to relieve pain. Surgical sympathectomy involves cutting the nerve or nerves, destroying the pain almost instantly, but surgery may also destroy other sensations as well.

What is the prognosis?
Good progress can be made in treating RSDS if treatment is begun early, ideally within three months of the first symptoms. Early treatment often results in remission. If treatment is delayed, however, the disorder can quickly spread to the entire limb, and changes in bone and muscle may become irreversible. In 50 percent of RSDS cases, pain persists longer than 6months and sometimes for years.

What is reflex sympathetic dystrophy/complex regional pain syndrome?

RSD/CRPS is a chronic condition characterized by severe burning pain, pathological changes in bone and skin, excessive sweating, tissue swelling, and extreme sensitivity to touch. The syndrome is a nerve disorder that occurs at the site of an injury (most often to the arms or legs). It occurs especially after injuries from high-velocity impacts such as those from bullets or shrapnel. However, it may occur without apparent injury.

The condition called "causalgia" was first documented in the 19th century by physicians concerned about pain that Civil War veterans continued to experience after their wounds had healed. Doctors often called it "hot pain," after its primary symptom. Over the years, the syndrome was classified as one of the peripheral neuropathies, and later, as a chronic pain syndrome. Currently, there are two types of CRPS that are differentiated-type I and type II. Both types share the same basic set of symptoms, but have one distinct difference: type I (previously referred to as RSD) describes cases in which there is no nerve injury, while type II (formerly called causalgia) refers to cases in which a distinct nerve injury, for example from a gunshot wound, has occurred

What are the symptoms of RSD/CRPS?
The symptoms of RSD/CRPS usually occur near the site of an injury, either major or minor, and include: burning pain, muscle spasms, local swelling, increased sweating, softening of bones, joint tenderness or stiffness, restricted or painful movement, and changes in the nails and skin. One visible sign of RSD/CRPS near the site of injury is warm, shiny red skin that later becomes cool and bluish.

The pain that patients report is out of proportion to the severity of the injury and gets worse, rather than better, over time. It is frequently characterized as a burning, aching, searing pain, which may initially be localized to the site of injury or the area covered by an injured nerve but spreads over time, often involving an entire limb. It can sometimes even involve the opposite extremity. Pain is continuous and may be heightened by emotional stress. Moving or touching the limb is often intolerable. Eventually the joints become stiff from disuse, and the skin, muscles, and bone atrophy.

The symptoms of RSD/CRPS vary in severity and duration. However, there are usually three stages associated with RSD/CRPS, and each stage is marked by progressive changes in the skin, nails, muscles, joints, ligaments, and bones. Stage one lasts from 1 to 3 months and is characterized by severe, burning pain at the site of the injury. Muscle spasm, joint stiffness, restricted mobility, rapid hair and nail growth, and vasospasm (a constriction of the blood vessels) that affects color and temperature of the skin can also occur.

In stage two, which lasts from 3 to 6 months, the pain intensifies. Swelling spreads, hair growth diminishes, nails become cracked, brittle, grooved, and spotty, osteoporosis becomes severe and diffuse, joints thicken, and muscles atrophy.

As the patient reaches stage three, changes in the skin and bones become irreversible, and pain becomes unyielding and may now involve the entire limb. There is marked muscle atrophy, severely limited mobility of the affected area, and flexor tendon contractions (contractions of the muscles and tendons that flex the joints). Occasionally the limb is displaced from its normal position, and marked bone softening is more dispersed.

What causes RSD/CRPS?
RSD/CRPS was originally thought to be the result of malfunctioning nerves of the sympathetic nervous system-the part of the nervous system responsible, for example, for controlling the diameter of blood vessels. This idea has been called into question and the mechanism remains controversial.

Since RSD/CRPS is most often caused by trauma to the extremities, other conditions that can bring about RSD/CRPS include sprains, fractures, surgery, damage to blood vessels or nerves, and cerebral lesions. The disorder is unique in that it simultaneously affects the nerves, skin, muscles, blood vessels, and bones.

Who gets it?
RSD/CRPS can strike at any age, but has usually been more common between the ages of 40 and 60. Recent reports show that the number of RSD/CRPS cases among adolescents and young adults is increasing. It affects both men and women, but is most frequently seen in women.

Investigators estimate that two to five percent of those with peripheral nerve injury and 12 to 21 percent of those with hemiplegia (paralysis of one side of the body) will suffer from RSD/CRPS.

How is RSD/CRPS diagnosed?
RSD/CRPS is often misdiagnosed because it remains poorly understood. Diagnosis is complicated by the fact that some patients improve without treatment. A delay in diagnosis and/or treatment for this syndrome can result in severe physical and psychological problems. Early recognition and prompt treatment provide the greatest opportunity for recovery.

RSD/CRPS is diagnosed primarily through observation of the symptoms. However, some physicians use thermography — a diagnostic technique for measuring blood flow by determining the variations in heat emitted from the body — to detect changes in body temperature that are common in RSD/CRPS. A color-coded "thermogram" of a person in pain often shows an altered blood supply to the painful area, appearing as a different shade (abnormally pale or violet) than the surrounding areas of the corresponding part on the other side of the body. An abnormal thermogram in a patient who complains of pain may lead to a diagnosis of RSD/CRPS. X-rays may also show changes in the bone.

What is the prognosis?
Good progress can be made in treating RSD/CRPS if treatment is begun early, ideally within 3 months of the first symptoms. Early treatment often results in remission. If treatment is delayed, however, the disorder can quickly spread to the entire limb and changes in bone and muscle may become irreversible. In 50 percent of RSD/CRPS cases, pain persists longer than 6 months and sometimes for years.

What is the treatment?
Physical therapy is the mainstay of therapy. Physicians use a variety of drugs to treat RSD/CRPS, including corticosteroids, vasodilators, and alpha- or beta-adrenergic-blocking compounds. Elevation of the extremity may be helpful. Injection of a local anesthetic, such as lidocaine, is sometimes used. Injections are repeated as needed. TENS (transcutaneous electrical stimulation), a procedure in which brief pulses of electricity are applied to nerve endings under the skin, has helped some patients in relieving chronic pain.

In some cases, surgical or chemical sympathectomy-interruption of the affected portion of the sympathetic nervous system-has been used to relieve pain. Surgical sympathectomy involves cutting the nerve or nerves, destroying the pain almost instantly. But surgery is controversial and may also destroy other sensations.

Are there any other disorders like RSDPS?/CR
RSD/CRPS has characteristics similar to those of other disorders, such as shoulder-hand syndrome, which sometimes occurs after a heart attack and is marked by pain and stiffness in the arm and shoulder; Sudeck's syndrome, which is prevalent in older people and in women and is characterized by bone changes and muscular atrophy, but is not always associated with trauma; and Steinbrocker's syndrome, which affects both sexes but is slightly more prevalent in women, and includes such symptoms as gradual stiffness, discomfort, and weakness in the shoulder and hand.

What research is being done?
The National Institute of Neurological Disorders and Stroke (NINDS), a part of the National Institutes of Health (NIH), supports and conducts research on the brain and central nervous system. Some studies are conducted at the Institute's own laboratories and clinics located in Bethesda, Maryland, on the NIH campus, while others are funded through grants to major medical institutions across the country. NINDS-supported scientists are studying new approaches to treat RSD/CRPS and intervene more aggressively after traumatic injury to lower the patient's chances of developing the disorder. Other studies to overcome chronic pain syndromes are discussed in the pamphlet " Pain: Hope Through Research," published by the NINDS.

Is help available?
The unrelenting pain from RSD/CRPS has caused many patients much physical and emotional misery. Family, friends, coworkers, and, regrettably, physicians themselves, may regard the patient as a complainer, thereby increasing the patient's distress. To meet the needs of individuals with RSD/CRPS and other conditions causing chronic pain, the following voluntary health agencies promote research, provide information, and may offer advice on coping. For information, write or call:

Reflex Sympathetic Dystrophy Syndrome Association (RSDSA)
P.O. Box 502
Milford, CT 06460
info@rsds.org
http://www.rsds.org
Tel: 203-877-3790
Fax: 203-882-8362

American RSDHope Group
P.O. Box 875
Harrison, ME 04040-0875
rsdhope@mail.org
http://www.rsdhope.org/
Tel: 207-583-4589

American Chronic Pain Association (ACPA)
P.O. Box 850
Rocklin, CA 95677-0850
ACPA@pacbell.net
http://www.theacpa.org
Tel: 916-632-0922 800-533-3231
Fax: 916-632-3208

National Chronic Pain Outreach Association (NCPOA)
P.O. Box 274
Millboro, VA 24460
ncpoa@cfw.com
http://www.chronicpain.org
Tel: 540-862-9437
Fax: 540-862-9485

Mayday Fund [For Pain Research]
c/o SPG
136 West 21st Street, 6th Floor
New York, NY 10011
MaydyFnd@aol.com
http://www.painandhealth.org
Tel: 212-366-6970
Fax: 212-838-2896

For information on other neurological disorders or research programs funded by the National Institute of Neurological Disorders and Stroke, contact the Institute's Brain Resources and Information Network (BRAIN) at:

BRAIN
P.O. Box 5801
Bethesda, Maryland 20824
301-496-5751
800-352-9424
www.ninds.nih.gov

Reviewed April 21, 2003