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DAPT may reduce MACE, mortality in patients with symptomatic PAD
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Dual antiplatelet therapy with aspirin and clopidogrel was associated with reduced rates of major adverse cardiac events and mortality at 3 years compared with aspirin monotherapy in patients with claudication or critical limb ischemia.
Researchers conducted an observational cohort study to compare DAPT with aspirin and clopidogrel (n = 348) vs. aspirin monotherapy (n = 281) in 629 patients. The mean age of the cohort was 67 years and 44% were women. Endovascular intervention was performed in 80% of patients.
At 3 years, the rate of MACE was 20% in the DAPT group vs. 28% in the monotherapy group (P = .03). Results of a propensity-matched analysis indicated that DAPT decreased the risk for MACE (adjusted HR = 0.65; 95% CI, 0.44-0.96) and overall mortality (adjusted HR = 0.55; 95% CI, 0.35-0.89) compared with monotherapy. DAPT failed to reduce risk for major amputation (adjusted HR = 0.69; 95% CI, 0.37-1.29). The researchers found no link between DAPT and target vessel revascularization during follow-up.
The researchers also conducted a subgroup analysis of 94 patients who had point-of-care platelet function testing. Of those, 55% exhibited decreased response to clopidogrel and 21% exhibited decreased response to aspirin. The researchers reported no association between reduced response to clopidogrel or aspirin and 1-year adverse event rates.
“These results suggest that DAPT may provide an additional long-term reduction in cardiovascular events among patients with lifestyle-limiting claudication or [critical limb ischemia],” the researchers concluded. “Additional randomized studies are warranted to assess the additive benefit of more intensive and DAPT among patients with advanced PAD.” – by Rob Volansky
Disclosure: One researcher reports consulting for Abbott, Bard, Boston Scientific, Covidien and Medtronic; another researcher reports consulting for Abbott, Medtronic and Spectranetics; and the other researchers report no relevant financial disclosures.
Perspective
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John H. Rundback, MD, FAHA, FSVM, FSIR
For patients with claudication, there are several trials, most notably the CAPRIE trial of clopidogrel vs. aspirin for patients with ischemia of the extremities, which showed benefit. In CAPRIE, there was 28% reduction in progression of ischemic events, notably progression of peripheral vascular symptoms. Aspirin has CV benefit and the CAPRIE data support antiplatelet therapy in symptomatic patients; however, prior studies have not clearly supported aspirin or clopidogrel in asymptomatic patients. So for patients with any symptomatic PAD with claudication, antiplatelet therapy is appropriate. In the absence of some sort of directed treatment, is has not been clear if DAPT or triple antiplatelet therapy is more advantageous without additional risk than single antiplatelet therapy.
Critical limb ischemia is a different scenario. In those patients, it is more about modifying risk after intervention, because for the most part those patients are not going to be treated with medical therapy alone. It’s more a question of whether antiplatelet therapy along with revascularization or another modality is beneficial.
With regard to treating patients with PAD, we have been practicing in the dark, extrapolating from CHARISMA and MATCH, which had PAD subsets, data from the Antiplatelet Trialists Group, and CAPRIE. We have had a notable lack of good data regarding the role of DAPT or triple antiplatelet therapy in vascular patients. This article does provide observational evidence that this therapy can be beneficial in preventing CV events without imposing much additional bleeding risk. The CV event finding is important because there is a 40% 5-year CV mortality rate in patients with PAD. Any mitigation of that would be a great advantage for our patients. No additional bleeding risk is important because that has been the biggest barrier to utilization of DAPT or triple antiplatelet therapy.
We need to look at prospective datasets and combine information on DAPT as well as cilostazol, triple antiplatelet therapy as well as vasodilators. We have limited data with regard to all of these, but a well-constructed prospective trial looking at different antiplatelet regimens in patients with PAD who do or do not undergo intervention would provide the high level of evidence that we need to treat our patients.
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