Peripheral Artery Disease Undertreated

Peripheral Artery Disease Undertreated

Megan Brooks

June 21, 2011 — Most adults in the United States who have peripheral artery disease (PAD) do not receive secondary preventive treatments that could reduce their risk for myocardial infarction (MI), stroke, and death, according to a report published online June 20 in Circulation.

The authors note that current guidelines for the management of patients with PAD recommend lipid-lowering therapy with a statin to achieve a goal LDL-cholesterol level of less than 100 mg/dL (or <70 mg/dL in high-risk patients), antihypertensive therapy to achieve systolic blood pressure lower than 140 mm Hg, and antiplatelet therapy.

Most studies of secondary prevention have included patients with PAD with previously recognized symptomatic disease, such as intermittent claudication or prior peripheral revascularization. Whether current guidelines can be extended to patients with asymptomatic PAD who have been identified by population screening using ankle-brachial index (ABI) has not been well studied.

“[O]ur data suggest that combination therapy with multiple risk-modifying therapies may be associated with clinical benefit in a population of individuals defined solely by an abnormal ABI,” report Reena L. Pande, MD, and colleagues from Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts.

7 Million Americans Have PAD

The researchers analyzed data on 7458 adults aged 40 years and older from the National Health and Nutrition Examination Survey (1999 – 2004), with mortality follow-up through the end of 2006.

The prevalence of PAD, defined as a low ABI of 0.90 or less, was 5.9%, which corresponds to roughly 7.1 million US adults with PAD.

Among these participants, statin therapy was reported in only about 30%, angiotensin-converting enzyme inhibitors/angiotensin receptor blocker therapy in roughly 25%, and aspirin therapy in about 36%. These percentages correspond to 5.0 million adults with PAD not taking statins, 5.4 million not taking an angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, and 4.5 million not receiving aspirin, the authors calculate.

After adjusting for age, sex, and race/ethnicity, PAD was associated with a greater than 2-fold increased risk for death (hazard ratio, 2.4; 95% confidence interval [CI], 1.9 – 2.9; P < .0001) during an average follow-up of 4.4 years.

Even after excluding adults with known cardiovascular disease, adults with PAD had higher death rates (16.1%) than those without PAD or cardiovascular disease (4.1%), with an adjusted hazard ratio of 1.9 (95% CI, 1.3 – 2.8; P = .001). “Thus, patients with PAD remain at high risk of all-cause mortality even in the absence of established cardiovascular disease,” the authors note.

Importantly, they say, use of 2 or more preventive therapies was associated with a 65% lower rate of death from any cause (hazard ratio, 0.35; 95% CI, 0.20 – 0.86; P = .02) in adults with PAD, but without cardiovascular disease.

“These observational findings highlight the critical need for a large-scale clinical trial to determine whether the implementation of secondary prevention therapies in high-risk individuals identified by ABI screening as having PAD can reduce mortality and cardiovascular events,” the investigators write.

The study was supported in part by grants from the National Heart, Lung and Blood Institute. The study authors are supported via grant funding from the institute and the American Heart Association. The authors have disclosed no relevant financial relationships.

Circulation. Published online June 20, 2011. Abstract

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