Objective To examine whether prospective bleeding risk estimates for patients undergoing percutaneous coronary intervention could improve the use of bleeding avoidance strategies and reduce bleeding. Design Prospective cohort study comparing the use of bleeding avoidance strategies and bleeding rates before and after implementation of prospective risk stratification for peri-procedural bleeding. Setting Nine hospitals in the United States. Participants All patients undergoing percutaneous coronary intervention for indications other than primary reperfusion for ST elevation myocardial infarction. Main outcome measures Use of bleeding avoidance strategies, including bivalirudin, radial approach, and vascular closure devices, and peri-procedural bleeding rates, stratified by bleeding risk. Observed changes were adjusted for changes observed in a pool of 1135 hospitals without access to pre-procedural risk stratification. Hospital level and physician level variability in use of bleeding avoidance strategies was examined. Results In a comparison of 7408 pre-intervention procedures with 3529 post-intervention procedures, use of bleeding avoidance strategies within intervention sites increased with pre-procedural risk stratification (odds ratio 1.81, 95% confidence interval 1.44 to 2.27), particularly among higher risk patients (2.03, 1.58 to 2.61; 1.41, 1.09 to 1.83 in low risk patients, after adjustment for control sites; P for interaction=0.05). Bleeding rates within intervention sites were significantly lower after implementation of risk stratification (1.0% v 1.7%; odds ratio 0.56, 0.40 to 0.78; 0.62, 0.44 to 0.87, after adjustment); the reduction in bleeding was greatest in high risk patients. Marked variability in use of bleeding avoidance strategies was observed across sites and physicians, both before and after implementation. Conclusions Prospective provision of individualized bleeding risk estimates was associated with increased use of bleeding avoidance strategies and lower bleeding rates. Marked variability between providers highlights an important opportunity to improve the consistency, safety, and quality of care.