Sex-specific differences in white matter microvascular integrity after ischaemic stroke

BACKGROUND AND PURPOSE: Functional outcomes after ischaemic stroke are worse in women, despite adjusting for differences in comorbidities and treatment approaches. White matter microvascular integrity represents one risk factor for poor long-term functional outcomes after ischaemic stroke. The aim of the study is to characterise sex-specific differences in microvascular integrity in individuals with acute ischaemic stroke. METHODS: A retrospective analysis of subjects with acute ischaemic stroke and brain MRI with diffusion-weighted (DWI) and dynamic-susceptibility contrast-enhanced (DSC) perfusion-weighted imaging obtained within 9 hours of last known well was performed. In the hemisphere contralateral to the acute infarct, normal-appearing white matter (NAWM) microvascular integrity was measured using the K (2) coefficient and apparent diffusion coefficient (ADC) values. Regression analyses for predictors of K (2) coefficient, DWI volume and good outcome (90-day modified Rankin scale (mRS) score <2) were performed. RESULTS: 105 men and 79 women met inclusion criteria for analysis. Despite no difference in age, women had increased NAWM K (2) coefficient (1027.4 vs 692.7×10(–6)/s; p=0.006). In women, atrial fibrillation (β=583.6; p=0.04) and increasing NAWM ADC (β=4.4; p=0.02) were associated with increased NAWM K (2) coefficient. In multivariable regression analysis, the K (2) coefficient was an independent predictor of DWI volume in women (β=0.007; p=0.01) but not men. CONCLUSIONS: In women with acute ischaemic stroke, increased NAWM K (2) coefficient is associated with increased infarct volume and chronic white matter structural integrity. Prospective studies investigating sex-specific differences in white matter microvascular integrity are needed.