Original title: Twelve or 30 Months of Dual Antiplatelet Therapy after Drug-Eluting Stents. Reference: Laura Mauri et al. N Engl J Med 2014;371:2155-66.

Dual antiplatelet therapy is recommended after a drug-eluting stent to prevent thrombotic complications. The clinical benefit of this scheme it is not clear beyond one year. Patients were registered to receive a pharmacological stent, after 12 months of treatment with a thienopyridine (clopidogrel or prasugrel) and aspirin. Patients were randomized to continue receiving dual antiplatelet therapy or aspirin plus placebo for another 18 months. The primary endpoint was stent thrombosis and a combined cardiovascular and cerebrovascular adverse event (death, myocardial infarction or stroke) during the period from 12 to 30 months. The primary safety end point was moderate or severe bleeding. A total of 9961 patients were randomized 1:1 to continue with dual antiplatelet therapy or aspirin plus placebo.

Continue with dual antiplatelet therapy up to 30 months compared with placebo reduced the rate of stent thrombosis (0.4% versus 1.4%; HR 0.29 CI 95% 0.17 to 0.48; p <0.001) and combined cardiovascular and cerebrovascular events (4.3% versus 5.9%; HR 0.71; CI 95% 0.59 to 0.85; p <0.001). The rate of stroke was also significantly lower in the group that continued with dual antiplatelet therapy up to 30 months (2.1% versus 4.1%; HR 0.47; p <0.001). The death rate was similar between both groups as opposed to moderate or severe bleeding resulted in the higher group receiving 30 months of dual antiplatelet therapy (2.5% versus 1.6%; p = 0.001). A higher risk of stent thrombosis and myocardial infarction was observed in both groups during the first 3 months of discontinuation of dual antiplatelet therapy. 

Conclusion

The dual antiplatelet therapy beyond the year after implantation of a drug-eluting stent compared with aspirin alone significantly reduces the risk of stent thrombosis and cardiovascular and cerebrovascular events combined, but in detriment of significantly increased risk of bleeding.

Editorial comment

Patients that possibly will benefit from a longer scheme, are those with most risk of thrombosis and myocardial yet with a low risk of bleeding. The study randomization exclude those who had bleeding events and ischemic events between the angioplasty day and 12 months. On one hand, it is logical not to continue exposing to bleeding for 18 months, those patients who already had the complication but otherwise excluded those who had ischemic events probably leaving out the group that would benefit most. All this excluded the 23% of the original population who had received at least one drug-eluting stent and therefore registered in the study. The significant reduction in the rate of heart attacks can be explained only 45% of the time by stent thrombosis. In over half of cases, averted heart attacks were spontaneous. The greatest benefit of continuing with the dual antiplatelet therapy was observed with paclitaxel-eluting stents, which expresses that this is not a class effect for all drug-eluting stents. Not all stents and not all patients are equal and perfect dual antiplatelet therapy time is yet to be determined.

SOLACI