ACTIVATED PROTEIN-C RESISTANCE IN ISCHEMIC STROKE NOT DUE TO FACTOR-VARGININE(506)-]GLUTAMINE MUTATION

Background and Purpose Resistance to activated protein C (APC), a natu ral plasma anticoagulant, is the most common identifiable risk factor for venous thromboembolic disease. One point mutation in coagulation f actor V that renders it APC-resistant is found in >90% of APC-resistan t venous thrombosis patients. To determine the prevalence of APC resis tance and of this factor V mutation in stroke, we screened a group of ischemic stroke patients. Methods Hispanic ischemic stroke patients we re screened using two different activated partial thromboplastin time- based assays. One assay using neat patient plasma determined APC resis tance, and the other assay using patient plasma diluted into factor V- deficient plasma determined APC-resistant factor V, including the Arg( 506)-->Gln mutation. Results were compared with those in 31 Hispanic c ontrol subjects of similar ages. Results Six of 63 (9.5%) stroke patie nts had APC resistance compared with none of 31 (0%) control subjects. No patient or control subject had APC-resistant factor V, ie, the fac tor V Arg(506)-->Gln mutation. Conclusions In Hispanic patients with i schemic stroke, the incidence (approximately 10%) of APC resistance is not caused by the factor V Arg(506)-->Gln mutation. APC resistance no t caused by this factor V mutation may be a risk factor for ischemic s troke in this population.