Background and Purpose-We sought to determine the incidence and severity of bleeding events in patients with stroke and cardiovascular diseases who were taking oral antithrombotic agents in Japan, where the incidence of hemorrhagic stroke is higher than in Western countries. Methods-A prospective, multicenter, observational study was conducted; 4009 patients who were taking oral antithrombotic agents for stroke and cardiovascular diseases were enrolled. The patients were classified into 4 groups according to their antithrombotic treatment: the single antiplatelet agent group (47.2%); the dual antiplatelet agent group (8.7%); the warfarin group (32.4%); and the warfarin plus antiplatelet agent group (11.7%). The primary end point was life-threatening or major bleeding according to the MATCH trial definition. Results-During a median follow-up of 19 months, there were 57 life-threatening and 51 major bleeding events, including 31 intracranial hemorrhages. The annual incidence of the primary end point was 1.21% in the single antiplatelet agent group, 2.00% in the dual antiplatelet agent group, 2.06% in the warfarin group, and 3.56% in the warfarin plus antiplatelet agent group (PϽ0.001). After adjustment for baseline characteristics, adding an antiplatelet agent to warfarin increased the risk of the primary end point (relative riskϭ1.76; 95% CI, 1.05 to 2.95), and adding another antiplatelet agent to single antiplatelet agent therapy increased the secondary end point of any bleeding, including minor events (relative riskϭ1.37; 95% CI, 1.07 to 1.76). Conclusions-The incidence of bleeding events during antithrombotic therapy in Japan was similar to that reported for Western countries, although the trials used different study designs. Dual antithrombotic therapy was independently related to an increased risk of bleeding events.

on behalf of The Bleeding With Antithrombotic Therapy (BAT) Study Group Background and Purpose-A prospective, multicenter, observational cohort study was conducted to clarify the association between major bleeding events and blood pressure (BP) levels during follow-up before development of bleeding events in antithrombotic users. Methods-A total of 4009 patients taking oral antithrombotic agents for cardiovascular or cerebrovascular diseases (2728 men, 69Ϯ10 years old) were followed. Changes in systolic and diastolic BPs between entry and the last clinic visit before intracranial hemorrhage (ICH) or extracranial hemorrhage were assessed. Results-Over a median follow-up of 19 months, ICH developed in 31 patients and extracranial hemorrhage developed in 77. Entry BP levels were similar among patients with ICH, those with extracranial hemorrhage, and those without hemorrhagic events. Both systolic BP and diastolic BP were relatively high during follow-up as compared with the levels at entry in patients with ICH, whereas they showed plateaus in patients with extracranial hemorrhage and patients without hemorrhagic events. Average systolic BP levels between 1 and 6 months (hazard ratio, 1.45; 95% CI, 1.08 to 1.92 per 10-mm Hg increase) and between 7 and 12 months (hazard ratio, 1.47; 95% CI, 1.05 to 2.01) as well as average diastolic BP levels between 7 and 12 months (hazard ratio, 2.05; 95% CI, 1.15 to 3.62) were independently associated with development of ICH after adjustment for established ICH predictors. The optimal cutoff BP level to predict impending risk of ICH was Ն130/81 mm Hg using receiver operating characteristic curve analysis. Conclusions-An increase in BP levels during antithrombotic medication was positively associated with development of ICH, suggesting the importance of adequate BP control for avoiding ICH. BP levels did not appear to be associated with extracranial hemorrhage. (Stroke.