Cardiologists' Input Critical to Integrated Management of PAD

Points to remember

• Peripheral artery disease (PAD) affects between 8 million and 12 million people in the United States. Its prevalence will likely reach 20 million in 10 years.
• The poor prognosis of PAD (disease affecting any of the upper- or lower-extremity carotid, renal, and mesenteric arteries) confers a markedly increased risk of subsequent ischemic cardiac and cerebrovascular events, reflecting the coexistence of often asymptomatic but extensive coronary and carotid disease.
• The notable overlap of incidence, natural history, and treatment outcomes between coronary and noncoronary atherosclerosis highlights the importance of cardiologists' participation in management of patients with PAD.

Types of atherosclerotic artery disease

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The challenge

Although 70% of patients with PAD may be asymptomatic at any given time, the presence of PAD is a powerful predictor of cardiovascular morbidity and mortality. The presence of asymptomatic PAD should therefore motivate both patients and clinicians to aggressively reduce cardiovascular risk factors in an attempt to limit events. Conversely, the presence of coronary or carotid disease should alert the physician to consider the coexistence of PAD.

Role of cardiologists in a global vascular care plan

Specific peripheral vascular disorders may also affect the management of cardiac disease:

• Renal artery stenosis (RAS) is the most common secondary cause of hypertension in patients with atherosclerosis. Moreover, renovascular hypertension is often resistant to medical therapy, thus increasing cardiovascular risk.
• Bilateral RAS may produce flash pulmonary edema in patients with normal left ventricular function.
• Subclavian artery stenosis may lead to angina or even myocardial infarction by compromising inflow to left or right internal mammary bypass grafts.
• Claudication from lower extremity artery disease may limit mobilization and impair the effectiveness of cardiac rehabilitation programs.
• Iliac and subclavian artery stenoses may limit access for cardiac catheterization and percutaneous coronary intervention.

Situations such as these have led to an increasing role for the input of cardiologists in the recognition and medical management of global vascular disease, as well as in therapeutic endovascular approaches for noncoronary revascularization.

Mayo Clinic uses an integrated approach, bringing together endovascular specialists from vascular medicine, vascular radiology, vascular surgery, and interventional cardiology to individualize an optimal patient treatment plan.

Claudication

The mainstay of therapy is risk factor modification in conjunction with antiplatelet therapy. A supervised exercise program along with pharmacologic therapy with phosphodiesterase inhibitors has additional proven benefit. Revascularization has typically been reserved for patients with persistent lifestyle limitations.

An increasing number of patients now undergo an endovascular rather than a surgical approach for revascularization of occlusive lower extremity artery disease. Patients who previously were considered too high risk for surgery are now eligible for percutaneous approaches, with the advantages of rapid recovery time and reduced morbidity.

In patients with severe obstructive disease or occlusions throughout a limb, treatment of proximal level stenoses alone often cures or markedly reduces claudication symptoms, despite residual high-grade occlusive disease more distally.

In other circumstances of complex disease patterns, a hybrid endovascular-surgical approach may be considered.

Critical limb ischemia

The presence of rest pain, nonhealing ulcer, or gangrene may represent critical limb ischemia (CLI). CLI is associated with mortality in 25% of patients and limb loss in 50% at 1 year.

The optimal treatment for CLI is prompt revascularization. The therapeutic goal is to reestablish single-vessel, in-line (uninterrupted) arterial flow to the foot. This outcome often requires multiple level dilation and endovascular reconstruction of at least a single infrapopliteal vessel.

Endovascular treatment of proximal disease alone to optimize collateralization of occluded infrapopliteal vessels may not always be sufficient for healing of distal extremity ulcers. If patency is maintained for even a short period, however, wound healing and limb salvage can be achieved.

Renal artery stenosis

The presence of atherosclerotic RAS is a risk factor for cardiovascular disease and a strong predictor of mortality. RAS may lead to hypertension, deterioration of renal function, and irreversible renal tissue injury (ischemic nephropathy).

Ultrasound confirming high-grade stenoses

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Radiograph of opened left renal artery

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It can be difficult to determine whether the relationship between RAS and hypertension or renal impairment is causative. Renal lesions can now be comprehensively assessed for both stenosis severity and downstream end-organ impact using tools from the coronary arena.

The incorporation of cardiac interventional techniques has expanded the treatments available for these challenging patients with vascular disease. For additional information or to refer a patient, please call the Department of Cardiovascular Diseases at 507-255-4244.

Clues to renal artery stenosis

• Known atherosclerosis
• Onset of hypertension before the age of 30 years or after the age of 55 years
• Worsening of previously controlled hypertension
• Malignant or resistant hypertension
• Abdominal bruit
• Discrepancy of renal size
• Azotemia not otherwise explained or worsened by angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers
• Recurrent congestive heart failure or flash pulmonary edema in a hypertensive patient, particularly with preserved systolic left ventricular function