Activated protein C resistance and acute ischaemic stroke: Relation to stroke causation and age

Objectives Resistance to activated protein C (APC) is the most frequent cause of thrombophilia and a well known risk factor for deep and cerebral vein thrombosis. Its causative role in ischaemic stroke is still a matter of debate. We undertook this study to determine the prevalence of APC-resistance in a cohort of consecutive patients with acute ischaemic stroke, especially with respect to patients' age and the underlying stroke causation. Materials and methods 489 patients with proven ischaemic stroke were included in this study. Subtypes of stroke were classified according to the TOAST criteria, i.e. large artery artherosclerosis (LAA), small vessel occlusion (SVO), cardioembolism (CE), stroke of other etiology (SOE), and stroke of undetermined etiology (SUE). APC-resistance was determined with a functional method with high sensitivity and specificity for the factor V Leiden mutation. The results were compared with the prevalence of APC-resistance in healthy volunteers, all born in the same area. Results APC-resistance was found in 24 of 489 patients (4.9 %) and in 6 of the 112 (5.4 %) control subjects. In the stroke patients, APC-resistance was distributed as follows: LAA 6.5 % (9/138), SVO 3.9 % (4/104), CE 6.7 % (7/104), SOE 3.6 % (1/28), SUE 2.6 % (3/115). Prevalence of APC-resistance was not significantly different between young stroke patients (6-45 years) and older patients (7.7 % [5/65] versus 4.5 % [19/424]). Conclusions Prevalence of APC-resistance is not increased in patients with ischaemic stroke. Additionally, no significant differences in the prevalence of APC-resistance are evident within the various stroke subtypes.