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09-09-2016 | Cardiology | News | Article

Prolonged DAPT shows benefit for PCI patients with peripheral artery disease

medwireNews: Research suggests that patients with peripheral artery disease (PAD), particularly those with acute coronary syndromes (ACS), may benefit from prolonged dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI).

The finding came from a subgroup analysis of the PRODIGY trial, a randomised study which compared the efficacy of prolonged and short DAPT in patients undergoing PCI.

The results, published in JAMA Cardiology, found that the presence of PAD had a significant adverse prognostic effect following PCI.

But the research also indicated that extending the duration of DAPT to 24 months significantly reduced the risk of major adverse events in these patients compared with short DAPT of 6 months or less.

“Although in the overall population of the PRODIGY trial prolonged DAPT was not more effective, the relative risk of the primary efficacy end point was approximately halved by prolonged DAPT in patients with PAD”, write authors Marco Valgimigli (Bern University Hospital, Switzerland) and colleagues.

Their subanalysis included 246 patients with history of PAD and 1724 patients without.

They found that within 2 years of PCI, the risk of the composite primary endpoint of death, myocardial infarction or cerebrovascular event was 75.0% higher among those with PAD (21.9 vs 8.4% in patients without PAD). Rates of overall mortality (15.8 vs 5.3%) and cardiac death (10.0 vs 2.9%) were also significantly higher in PAD patients.

However, among patients with PAD, prolonged DAPT was associated with a 46% reduced risk of the primary endpoint compared with short DAPT (16.1 vs 27.3%), primarily due to an effect on risk of death. By contrast, no such relationship between DAPT duration and the primary endpoint was observed in patients without PAD.

The effect of prolonged DAPT appeared even greater in PAD patients with ACS at presentation; among these patients the primary endpoint occurred in 32.2% assigned to receive short DAPT and 16.9% assigned to receive the prolonged regime (HR= 0.46).

Additionally, the authors report that the risks of bleeding were not affected by DAPT duration. They say this finding could be related to the high incidence of ischaemic events in PAD patients or the small sample size, but is consistent with other reports.

Along with the restricted power of their study, the findings are also limited by the fact that assignment to receive short or prolonged DAPT was not stratified by by PAD status and the analysis was not prespecified.

“Overall, our results should be considered hypothesis generating for future dedicated randomized clinical trials”, they say.

Writing in an accompanying editorial, Marc Bonaca, from the Brigham and Women’s Hospital Heart & Vascular Center in Boston, Massachusetts, USA, says the findings will help clinicians to select patients at the highest risk who may benefit the most from intensive antiplatelet treatment.

“Taken together with other recent subgroup analyses, these data help to shine a welcomed spotlight on a population of patients at high ischemic risk, including limb ischemic risk, and that until recently has had few proven therapies”, he writes. However, he notes that future research should also focus on the rates of adverse limb events, which are high among patients with PAD.

“Hopefully the continued recognition of the risk to life and limb in patients with PAD coupled with encouraging data demonstrating that this can be modified with potent pharmacologic strategies will continue to drive research into newer and better therapies”, Bonaca concludes.

By Kirsty Oswald

medwireNews is an independent medical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2016