This variable may prove to be a relevant when designing improved thrombectomy strategies, researchers suggest.
Men tend to have larger cerebral artery diameters than women, and this disparity could explain why male stroke patients may see better outcomes than women after mechanical thrombectomy, new findings hint.
Although the clinical benefit of mechanical thrombectomy has been demonstrated for acute ischemic stroke, “multiple studies report a gender disparity in postthrombectomy outcomes, with females faring worse than males,” write investigators led by Mark A. Davison, MD, (Rush University Medical Center, Chicago, IL), in their paper published online this month in the Journal of NeuroInterventional Surgery.
“Gender differences have been reported in circle of Willis cerebral aneurysm distribution and vessel caliber,” they add. “Based on the Hagen-Poiseuille equation, vascular caliber could influence ischemic stroke outcomes as the arterial diameter proportionally affects the volumetric vessel flow rate.”
The observational study looked at 92 consecutive acute ischemic stroke patients, 42 of whom were women, who underwent mechanical thrombectomy at a single, urban tertiary care medical center between June 2013 and August 2016. Researchers used catheter angiographic images to manually measure proximal segment arterial diameters in a standardized fashion and medical records to obtain relevant independent and dependent variables.
Diameters of both the internal carotid artery (ICA) terminus and the M1 segment middle cerebral artery (MCA) were narrower for women than men.
Mean (SD) Vessel Diameters by Patient Sex
|
|
Male (n = 50) |
Female (n = 42) |
P Value |
|
ICA Terminal, mm |
3.08 (0.46) |
2.81 (0.45) |
0.01 |
|
M1 Segment MCA, mm |
2.47 (0.30) |
2.18 (0.31) |
< 0.0001 |
Overall, 48% of patients in the upper MCA caliber tertile attained a favorable outcome, defined as a 90-day mRS 0-2, compared with 35% of those in the middle and lower tertiles (P = 0.51).
A total of 29.6% of patients in the upper tertile for vessel diameter were discharged home, compared with 3.8% in the middle tertile and 19.2% in the lower tertile. In addition, 7.4% of patients in the upper tertile were discharged to a skilled nursing facility, compared with 23.1% in the middle tertile and 19.2% in the lower tertile. The differences in discharge disposition, however, failed to reach statistical significance (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,” write the authors.
Prior research has relied on noninvasive imaging such as CT and MR angiography to assess flow patterns of cerebral emboli as well as how physiologic stimuli can affect vessel dimensions, Davison and colleagues point out.
“Unique to the current study was the use of [digital subtraction angiography], which is fortunately inherent to thrombectomy, and allows for highly precise vessel diameter measurements,” they explain, concluding, “If future studies validate these findings, arterial diameter may become a relevant variable in the design of improved thrombectomy strategies.”
Source:
Davison MA, Ouyang B, Keppetipola KM, et al. Arterial diameter and the gender disparity in stroke thrombectomy outcomes. J NeuroInterv Surg. 2018;Epub ahead of print.
Disclosure:
Davison reports no relevant conflicts of interest.
