A Meta-analysis Of The Two Antithrombotic Regimens After Stent Implantation In Patients Under Chronic Oral Anticoagulant Treatment

Background:There are an increasing number of patients with an indication of long-term oral anticoagulant (OAC) that has undergone PCI/stenting (PCI-s). However, the optimal antithrombotic treatment for these patients is currently unknown.Purpose:To characterize the benefits and risks of triple antithrombotic therapy (combined aspirin, clopidogrel and OAC) after stent implantation in patients under chronic OAC treatment compared with dual antiplatelet therapy (combined aspirin and clopidogrel).Data Sources:Clinical controlled trials published up to June 2009 in PubMed, Cochrane Library, reviews, and reference lists of relevant papers.Study Selection:Clinical controlled trials with no less than 3 months of follow-up that compared triple antithrombotic therapy with dual antiplatlet therapy after stent implantation in patients under chronic OAC treatment.Data Extraction:Two reviewers independently extracted information regarding study characteristics and occurrences of major bleeding in the first 6 month during follow-up, minor bleeding, ischemic stroke, major adverse cardiac events (MACE), and all-cause mortality in the study. Data Synthesis:Nine clinical trials included 1,996 participants. As a whole, patients who were considered at a high risk for development of thrombotic events or at a complicated situation were treated with triple antithrombotic therapy whereas patients considered at higher risk for bleeding events received only dual antiplatelet therapy in the post stenting period. The meta-analysis was feasible since the grouping criterion was similar. The meta-analysis of prevention of MACE shows more efficacious in favor of triple antithrombotic therapy compared with dual antiplatelet therapy (OR,0.66; 95%CI,0.47-0.93; P=0.02). In contrast, there was no significant difference in the incidence of stroke. There was, however, a trend towards the higher incidence of stroke in the dual antiplatelet therapy (OR,0.48; 95%CI,0.16-1.40; P=0.18). For all-cause mortality, there was a significant reduction with triple antithrombotic therapy compared with dual antiplatelet therapy (OR,0.63; 95%CI, 0.42-0.95; P=0.03). The meta-analysis of major bleeding in the first 6 months during follow-up shows significantly more events with triple antithrombotic therapy (OR, 2.03; 95%CI,1.00-4.13; P=0.05). Similarly, there was a significant difference between the two groups in the incidence of minor bleeds with higher incidence in patients receiving triple antithrombotic therapy than dual antiplatelet therapy (OR, 1.57; 95%CI,1.06-2.32; P=0.03).Conclusions:Based on our analysis, triple antithrombotic therapy is substantially more efficacious to reduce the occurrence of cardiovascular events and mortality in PCI-s patients with an indication of long-term OAC, compared with dual antiplatlet therapy. Though the triple therapy predisposes to an increased risk of bleeding, especially the occurrence of major bleeding, it is the better choice for patients with a low bleeding risk.