Arterial diameter and the gender disparity in stroke thrombectomy outcomes

Compared with males, females consistently fare worse following mechanical thrombectomy for large vessel ischemic strokes. Understanding why this gender disparity occurs may guide improvements in future treatment strategies. In this study, we aim to determine whether gender differences in cerebral arterial diameter correlate with clinical outcomes following stroke thrombectomy.

We performed an observational study of consecutive acute ischemic stroke patients undergoing mechanical thrombectomy at a single, urban tertiary care medical center. Catheter angiographic images were used to manually measure proximal segment arterial diameters in a standardized fashion. Medical record review was used to obtain relevant independent and dependent variables.

Ninety two patients (42 females) between June 2013 and August 2016 met inclusion criteria. Internal carotid artery (ICA) terminus diameters for males and females were 3.08 mm (SD=0.46) and 2.81 mm (SD=0.45), respectively (P=0.01). M1 segment middle cerebral artery (MCA) diameters for males and females were 2.47 mm (SD=0.30) and 2.18 mm (SD=0.31), respectively (P<0.0001). 48% of patients in the upper MCA caliber tertile attained a favorable mRS 90 day value compared with 35% in each of the lower and middle tertiles (P=0.51). Larger MCA diameters correlated with favorable discharge disposition (P=0.21).

These results provide limited evidence that males have larger cerebral arterial diameters than females and that larger arterial diameters may improve the odds for favorable clinical outcomes. If future studies validate these findings, arterial diameter may become a relevant variable in the design of improved thrombectomy strategies.