Warfarin plus Aspirin after Myocardial Infarction or the Acute Coronary Syndrome: Meta-Analysis with Estimates of Risk and Benefit

View larger version (17K): [in a new window]   Figure 1. Forest plot showing rate ratios of myocardial infarction for warfarin plus aspirin compared with aspirin alone. APRICOT-2 = Antithrombotics in the Prevention of Reocclusion In Coronary Thrombolysis-2; ASPECT-2 = Antithrombotics in the Secondary Prevention of Events in Coronary Thrombosis-2; ATACS = Antithrombotic Therapy in Acute Coronary Syndromes; OASIS = Organization to Assess Strategies for Ischemic Syndromes; WARIS II = Warfarin, Aspirin, Reinfarction Study.

View larger version (13K): [in a new window]   Figure 2. Forest plot showing rate ratios of ischemic stroke for warfarin plus aspirin compared with aspirin alone. Studies with excluded rate ratios had no events in either group. ASPECT-2 = Antithrombotics in the Secondary Prevention of Events in Coronary Thrombosis-2; OASIS = Organization to Assess Strategies for Ischemic Syndromes; WARIS II = Warfarin, Aspirin, Reinfarction Study.

View larger version (16K): [in a new window]   Figure 3. Forest plot showing rate ratios of death for warfarin plus aspirin compared with aspirin alone. The study with an excluded rate ratio had no events in either group. APRICOT-2 = Antithrombotics in the Prevention of Reocclusion In Coronary Thrombolysis-2; ASPECT-2 = Antithrombotics in the Secondary Prevention of Events in Coronary Thrombosis-2; ATACS = Antithrombotic Therapy in Acute Coronary Syndromes; OASIS = Organization to Assess Strategies for Ischemic Syndromes; WARIS II = Warfarin, Aspirin, Reinfarction Study.

View larger version (17K): [in a new window]   Figure 4. Forest plot showing rate ratios of major bleeding for warfarin plus aspirin compared with aspirin alone. The study with an excluded rate ratio had no events in either group. APRICOT-2 = Antithrombotics in the Prevention of Reocclusion In Coronary Thrombolysis-2; ASPECT-2 = Antithrombotics in the Secondary Prevention of Events in Coronary Thrombosis-2; ATACS = Antithrombotic Therapy in Acute Coronary Syndromes; OASIS = Organization to Assess Strategies for Ischemic Syndromes; WARIS II = Warfarin, Aspirin, Reinfarction Study.

View this table: [in a new window]   Appendix Table 1. Design of Trials Included in the Meta-Analysis

View this table: [in a new window]   Appendix Table 2. Tests of Heterogeneity

View larger version (34K): [in a new window]   Figure 5. Predicted myocardial infarctions (MIs) and thrombotic strokes averted and excess bleeding episodes caused in 1000 patients as a result of adding warfarin to aspirin for 1 year, stratified by bleeding and MI risk. Numbers of cardiovascular events are the differences between the MI rates (aspirin rate – aspirin rate x risk ratio) plus the difference in stroke rates (baseline rates not shown) multiplied by 1000 patient-years. The number of bleeding episodes represents the difference in bleeding rates (combination rate – combination rate/risk ratio for major bleeding episode) multiplied by 1000. Letters and corresponding dots represent actual combinations of bleeding and cardiovascular risk from Table 2. The shaded area in the parallelogram represents unfavorable risk or benefit. APRICOT-2 = Antithrombotics in the Prevention of Reocclusion In Coronary Thrombolysis-2; ASPECT-2 = Antithrombotics in the Secondary Prevention of Events in Coronary Thrombosis-2; ATACS = Antithrombotic Therapy in Acute Coronary Syndromes; OASIS = Organization to Assess Strategies for Ischemic Syndromes; WARIS II = Warfarin, Aspirin, Reinfarction Study.

View larger version (35K): [in a new window]   Appendix Figure 1. Process of study selection.

View larger version (15K): [in a new window]   Appendix Figure 2. Forest plot showing rate ratios of percutaneous transluminal coronary angioplasty or coronary artery bypass grafting for warfarin plus aspirin compared with aspirin alone. The study with an excluded rate ratio had no events in either group. APRICOT-2 = Antithrombotics in the Prevention of Reocclusion In Coronary Thrombolysis-2; ASPECT-2 = Antithrombotics in the Secondary Prevention of Events in Coronary Thrombosis-2; ATACS = Antithrombotic Therapy in Acute Coronary Syndromes; OASIS = Organization to Assess Strategies for Ischemic Syndromes; WARIS II = Warfarin, Aspirin, Reinfarction Study.

View larger version (18K): [in a new window]   Appendix Figure 3. Forest plot showing rate ratios of minor bleeding for warfarin plus aspirin compared with aspirin alone. APRICOT-2 = Antithrombotics in the Prevention of Reocclusion In Coronary Thrombolysis-2; ASPECT-2 = Antithrombotics in the Secondary Prevention of Events in Coronary Thrombosis-2; ATACS = Antithrombotic Therapy in Acute Coronary Syndromes; OASIS = Organization to Assess Strategies for Ischemic Syndromes; WARIS II = Warfarin, Aspirin, Reinfarction Study.