Hypercoagulability is a stronger risk factor for ischaemic stroke than for myocardial infarction: A systematic review

Background and Purpose: Hypercoagulability increases the risk of arterial thrombosis; however, this effect may differ between various manifestations of arterial disease. Methods: In this study, we compared the effect of coagulation factors asmeasures of hypercoagulability on the risk of ischaemic stroke (IS) and myocardial infarction (MI) by performing a systematic review of the literature. The effect of a risk factor on IS (relative risk for IS, RR<inf>IS</inf>) was compared with the effect on MI (RR<inf>MI</inf>) by calculating their ratio (RRR = RR<inf>IS</inf>/RR<inf>MI</inf>). A relevant differential effect was considered when RRR was >1+ its own standard error (SE) or <1-SE. Results: We identified 70 publications, describing results from 31 study populations, accounting for 351 markers of hypercoagulability. The majority (203/351, 58%) had an RRR greater than 1. A larger effect on IS risk than MI risk (RRE>1+1SE) was found in 49/343 (14%) markers. Of these, 18/49 (37%) had an RRR greater than 1+2SE. On the opposite side, a larger effect on MI risk (RRR<1-1SE) was found in only 17/343 (5%) markers. Conclusions: These results suggest that hypercoagulability has a more pronounced effect on the risk of IS than that of MI.