Management of Peripheral Vascular Disease

Dr. William E. Golden and Dr. Robert H. Hopkins

Diseases of arteries outside the coronary circulation contribute to significant morbidity and mortality in adults. The American College of Cardiology and the American Heart Association, in collaboration with the Society for Vascular Surgery and other societies, recently released guidelines for the management of peripheral arterial disease in the lower extremities, abdominal aorta, renovascular system, and mesenteric vascular beds.

This review will focus on lower-extremity peripheral arterial disease (PAD).

Conclusions

The principal cause of lower extremity PAD is atherosclerosis. Risk factors, some of which are modifiable, include smoking, diabetes, hyperlipidemia, hypertension, and hyperhomocysteinemia. Patients with PAD are at high risk for future cardiovascular events.

The ankle-brachial index (ABI) is used in the assessment of PAD and is calculated by dividing the systolic pressure at the ankle by the systolic pressure in the brachial artery. The ABI is measured with a sphygmomanometer with an appropriately sized cuff and handheld Doppler device. Normal values are 0.91-1.30.

Critical limb ischemia (CLI) is defined by the presence of ischemic rest pain, gangrene, or ischemic ulcers. Patients with these findings are likely to require amputation within 6 months if the disease is left untreated. However, claudication does not usually progress to limb-threatening ischemia.

Implementation

Patients aged 50 years and older with atherosclerosis risk factors and all persons over 70 years should be assessed for history of walking impairment, claudication, nonhealing lower extremity wounds, and ischemic rest pain. The presence of any of these features suggests the presence of PAD.

The ABI should be measured in all patients suspected of having PAD. The toe-brachial index is a useful test for PAD in patients with noncompressible vessels, which render the ABI uninterpretable.

Exercise ABI is indicated in patients at risk of developing PAD who have a normal resting ABI; it can also provide objective evidence of the degree of functional limitation and response to therapy. Arterial imaging is generally not indicated in patients with a normal exercise ABI.

Patients with PAD should receive comprehensive treatment including tobacco cessation, lipid reduction (to an LDL level less than 100 mg/dL or less than 70 mg/dL in the highest risk patients), and hypertension control.

The blood pressure goal should be less than 130/80 with diabetes or renal disease and less than 140/90 in other patients. In diabetics, PAD treatment should also include good glycemic control to a hemoglobin A1c level of less than 7%, in accord with current guidelines for patients with established coronary disease.

Aspirin (75-325 mg daily) or clopidogrel (75 mg daily) is indicated for antiplatelet therapy in patients with PAD. The available data do not support either aspirin/ clopidogrel combination therapy or warfarin treatment to reduce the risk of future cardiovascular events. Vitamin B-12 and folate supplementation in patients with hyperhomocysteinemia and PAD have not been found beneficial.

Supervised exercise training is of benefit in many individuals with lower extremity PAD and is recommended as an initial treatment in patients with intermittent claudication.

Cilostazol (100 mg b.i.d.) is effective in many patients with claudication due to lower extremity peripheral arterial disease, and a therapeutic trial is indicated in such patients who do not have concomitant heart failure. Pentoxifylline (400 mg t.i.d.) may be tried as an alternate to cilostazol, but its clinical effectiveness is less well established.

None of the following medications/interventions have demonstrated efficacy in the treatment of vascular claudication: L-arginine, propionyl-L-carnitine, ginkgo biloba, oral vasodilator prostaglandins, vitamin E, and EDTA chelation. Some of these treatments may have harmful effects.

Duplex and continuous-wave ultrasonography, CT angiography, and MR angiography (with gadolinium contrast) all have utility in localizing vascular lesions in patients with peripheral arterial disease who are being evaluated for interventional management. Digital subtraction angiography is recommended for the evaluation of patients whose treatment plan includes revascularization.

Endovascular or surgical interventions are indicated for patients who have disability due to claudication, have failed to respond to medical interventions, have reasonable procedural risk, and are likely to benefit from the procedure.

However, prophylactic endovascular or surgical intervention is not indicated in patients with asymptomatic lower extremity PAD. Patients who have undergone vascular interventions require regular surveillance for at least 2 years after they have the procedure.

Patients who have claudication symptoms before age 50 appear to have more aggressive atherosclerosis and have a worse prognosis for long-term response to vascular surgery; as such, surgery should be avoided in these patients if possible.

Patients with critical limb ischemia require urgent vascular evaluation to determine if the limb is salvageable, or whether amputation must be considered. Systemic antibiotics are indicated in patients with CLI and gangrene or skin ulceration, and intravenous prostaglandin E-1 for 7-28 days can reduce ischemic pain and facilitate ulcer healing in a subset of patients with CLI.

Catheter-based thrombolysis is effective and beneficial in patients who have acute CLI (of less than 14 days), and mechanical thrombectomy can be a useful adjunct

Reference

Hirsch, et al. ACC/AHA Guidelines for the Management of Patients with Peripheral Arterial Disease (Lower Extremity, Renal, Mesenteric and Abdominal Aortic): A Collaborative Report.

See the Web site, www.acc.org/clinical/guidelines/pad/index.pdf.