Aspirin May Not Effectively Treat Peripheral Artery Disease

Daily low-dose aspirin not observed to affect mortality rate of patients with peripheral artery disease.​

The US Preventive Services Task Force recommends low-dose aspirin for adults aged 50 to 69 to help prevent the development of cardiovascular disease and colorectal cancer. A low-dose aspirin regimen is recommended by the American Heart Association for individuals who have experienced a heart attack and those at high-risk for a cardiovascular event, as well.

Many patients with peripheral vascular disease (PVD), a condition that features narrowed arteries, also take daily aspirin to improve health. The CDC reports that more than 8.5 million Americans have PVD, with individuals aged 50 and older accounting for 20% of the population.

Findings from a study published by PLOS One indicates that aspirin therapy among these patients may not impact cardiovascular disease or mortality.

Included in the meta-analysis were 6560 patients with PVD who participated in clinical trials involving aspirin. Approximately 60% of patients were women, 32% had diabetes, and 67% currently smoked or had a history of smoking.

The authors discovered that taking low-dose aspirin had no effect on mortality and incidences of stroke, heart, attack, or major cardiac events among patients with PVD, according to the study.

"Among patients with peripheral vascular disease, many of them may not be deriving the benefits from aspirin that they expect to be getting," said researcher Anthony A. Bavry, MD.

After 6 years, 7.7% of patients taking aspirin died compared with 8.5% of the control group, according to the study. Approximately 3.2% of aspirin users experienced a stroke after 6 years compared with 4% of the control group.

The authors also found that 3.5% of patients taking aspirin experienced a heart attack, while 5.5% of the control group experienced this event. The rate of other major cardiac and cerebrovascular events was observed to be similar between both cohorts, according to the study.

Although aspirin seemed to offer little benefit to these patients, the authors note that all differences were not statistically significant.

While the role of aspirin was unclear, the authors reported no difference in bleeding risks among patients who did and did not take aspirin. There was a slight trend of higher bleeding among aspirin-taking patients, but the authors said it was not enough to draw a conclusion.

This is the most recent analysis to compare outcomes for this population in relation to aspirin, but it is not the final recommendation. The authors caution that the analysis was limited by the fact that multiple trials were conducted before cholesterol-controlling drugs were standard. These findings should be supplemented by larger, randomized clinical trials, according to the study.

The authors do not advise patients with PVD to stop treatment with aspirin to reduce cardiovascular problems, but should consult their physicians. They also said that their findings highlight the need for additional studies that explore the treatment in patients with PVS and other conditions, including ischemic heart disease, according to the study.

"Aspirin might not be a miracle drug for certain patients,” said co-author Ahmed N. Mahmoud, MD. “We need to reconsider the evidence, and see who benefits from aspirin therapy and who does not.”