RESUMEN
AIMS: Platelets play an important role in cardiovascular disease, and ß-blockers are often prescribed for cardiovascular disease prevention. ß-Blockers may directly affect platelet aggregation, because ß-adrenergic receptors are present on platelets. There is uncertainty about the existence and magnitude of an effect of ß-blockers on platelet aggregation. The aim of this study was to perform a systematic review and meta-analysis of the effect of ß-blockers on platelet aggregation. METHODS: MEDLINE and EMBASE were searched until April 2014. Two reviewers independently performed data extraction and risk of bias assessment. Type of ß-blocker, population, treatment duration and platelet aggregation were extracted. Standardized mean differences were calculated for each study and pooled in a random-effects meta-analysis. RESULTS: We retrieved 31 studies (28 clinical trials and three observational studies). ß-Blockers decreased platelet aggregation (standardized mean difference -0.54, 95% confidence interval -0.85 to -0.24, P < 0.0001). This corresponds to a reduction of 13% (95% confidence interval 8-17%). Nonselective lipophilic ß-blockers decreased platelet aggregation more than selective nonlipophilic ß-blockers. CONCLUSIONS: Clinically used ß-blockers significantly reduce platelet aggregation. Nonselective lipophilic ß-blockers seem to reduce platelet aggregation more effectively than selective nonlipophilic ß-blockers. These findings may help to explain why some ß-blockers are more effective than others in preventing cardiovascular disease.