Background: Women are known to have worse post-stroke outcomes; however, the underlying mechanisms remain unclear. We evaluated sex-specific clinical and neuroimaging characteristics linked to cerebrovascular brain health in association with functional recovery after acute ischemic stroke (AIS).
Methods: We reviewed 316 AIS patients with acute MRI (<48 hours from symptom onset) and modified Rankin scale score (mRS) assessed at 3-6 months post-stroke. Acute infarct volume on diffusion-weighted imaging (DWIv) and white matter hyperintensity volume (WMHv) on FLAIR sequences were determined using a validated semi-automated method. Mean diffusivity (MD) and fractional anisotropy (FA) of normal appearing white matter (NAWM) were derived from the contralesional hemisphere. Wilcoxon rank sum, Spearman correlation, and Fisher’s exact tests were used at p-value <0.05, as appropriate.
Results: Women comprised 41.1% of this AIS cohort, and as compared to men, they were older (68 vs. 62.8 years, p = 0.002), had higher prevalence of atrial fibrillation (21.5% vs. 12.4%, p = 0.04), and less tobacco use (21.1% vs. 36.3%, p = 0.03). There was no statistically significant difference between men and women in admission stroke severity, TOAST stroke subtype distribution, DWIv or WMHv. However, women were significantly less likely to have a favorable outcome (mRS <2), as compared to men (53.7% vs. 68.5%, p = 0.01). Both FA (ρ -0.18, p=0.04) and MD (ρ 0.28, p=0.002) values in NAWM correlated with follow-up mRS in women, but only MD (ρ 0.26, p=0.0004) in men.
Conclusion: Despite no differences in admission NIHSS, acute infarct size, WMH burden or stroke subtype, women with AIS had significantly worse post-stroke
outcomes in our cohort. Our findings suggest that microstructural integrity, as assessed by NAWM diffusivity anisotropy measurements, may represent a neuroimaging correlate of worse outcomes in women. The correlation between markers of white matter microstructural integrity and long-term mRS provides insight into the underlying mechanisms of disease that may influence functional recovery after stroke.