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 as measures 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, RRIS) was compared with the effect on MI (RRMI) by calculating their ratio (RRR = RRIS/RRMI). 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.