The WOEST ( What is the Optimal Antiplatelet and Anticoagulant Therapy in Patients With Oral Anticoagulation and Coronary Stenting ) trial randomized 573 patients on oral anticoagulants undergoing stenting to either Clopidogrel ( Plavix ) alone ( dual therapy ) or Clopidogrel plus low-dose Acetylsalicylic acid ( Aspirin ) ( triple therapy ).
At 1 year, the primary outcome ( TIMI major, minor, and minimal bleeding ) occurred in 19.5% in the dual-therapy group and in 44.9% in the triple-therapy group ( hazard ratio, HR=0.36; P less than 0.001; number needed to treat, NNT=4 ).
Myocardial infarction ( 3.2% versus 4.6% ), stroke ( 1.1% versus 2.8% ), target vessel revascularization ( 7.2% versus 6.7% ), and stent thrombosis ( 1.4% versus 3.2% ) did not differ significantly between the groups, but all-cause mortality at 1 year was lower in the dual-therapy group than in the triple-therapy group ( 2.5% versus 6.3%; P=0.027 ).
The combination of the ischemic end points occurred in 11.1% in the double-therapy group and 17.6% in the triple-therapy group ( HR=0.56 ).
Thus, triple therapy after stenting in Warfarin-treated patients doubled the bleeding rate in this randomized trial compared with dual therapy with aspirin omitted ( NNT=4 ).
Interestingly, thrombotic risk, including stent thrombosis, was not increased by omitting Aspirin, and all-cause mortality was reduced by more than half.
Of course, this trial was too small to exclude the risk of omitting Aspirin in the high-risk population of patients with stent thrombosis or myocardial infarction. ( Xagena )
Currently, two randomized trials are evaluating the risks and benefits of triple antithrombotic therapy ( Aspirin, Clopidogrel and Warfarin ) compared with safer antithrombotic therapy in anticoagulated patients after coronary stent implantation: the Triple Therapy in Patients on Oral Anticoagulation After Drug Eluting Stent Implantation in Germany and the Anticoagulation in Stent Intervention trial ( MUSICA-2 ) in Spain.
The outcomes of these trials will guide the management of this difficult group of patients. ( Xagena )
Verheugt FWA, Circulation 2013; 128: 2058-2061