The PARIS (patterns of non-adherence to anti-platelet regimens in stented patients) registry is a prospective observational study of patients from the US and Europe who were discharged on dual anti-platelet therapy (DAPT) following coronary stenting. Among 5018 patients from this registry, the rates of physician recommended discontinuation, brief interruption (i.e. for surgery), or disruption (ie non-compliance, bleeding) of DAPT was assessed over 2 years. The observed rate of discontinuation was 40.8%, interruption 10.5,%, and the rate of DAPT disruption was 14.4%. Patients with DAPT disruption were at significantly increased risk for major cardiovascular events compared with patients on DAPT (hazard ratio 1.50, 95% CI 1.14 – 1.97), with highest risk in the first 7 days of disruption (hazard ratio 7.04, 95% CI 3.31 – 14.95). In contrast, there was a lower risk for major adverse cardiovascular events among patients who had DAPT discontinued in comparison to patients who remained on DAPT (hazard ratio 0.63, 95% CI 0.46 – 0.86).

Conclusions:

This study suggests there is no clinical benefit to an extended duration of DAPT following PCI. However, the study cannot eliminate potential treatment bias resulting from discontinuation of DAPT in the lowest risk patients. Randomized trial data are still needed to inform best practices.

Summarized by Steven M. Bradley and Preston M. Schneider

• Mehran R, Baber U, Steg PG, et al. Cessation of dual antiplatelet treatment and cardiac events after percutaneous coronary intervention (PARIS): 2 year results from a prospective observational study. The Lancet. 23;382(9906):1714–1722. doi:10.1016/S0140-6736(13)61720-1.