No Sex Differences in Outcomes After Endovascular Thrombectomy for LVO Stroke
Key findings
- This retrospective analysis included 381 patients who underwent endovascular thrombectomy (EVT) for stroke secondary to emergent large vessel occlusion between January 2011 and September 2019
- Rates of adequate reperfusion, functional independence at 90 days and good outcome at 90 days were comparable in men and women, even though women were significantly older and significantly more likely to have pre-stroke disability
- However, sex-specific determinants of EVT outcomes were identified; cervical internal carotid atherosclerosis and dissection independently decreased the odds of adequate reperfusion in men but not women
- Further, older age, higher stroke scale score and not achieving adequate reperfusion independently decreased the odds of good outcomes among both sexes, while prior stroke and intracerebral hemorrhage were determinants exclusive to men
Endovascular thrombectomy (EVT) has transformed the care of strokes that are secondary to emergent large vessel occlusion (ELVO). However, some clinical trial evidence suggests women have worse outcomes than men.
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To understand possible sex-based differences, researchers at Massachusetts General Hospital studied patients who underwent EVT over a wide span of years of changing protocols. They found no differences between men and women in reperfusion rates or change in functional outcomes, but some determinants of those outcomes were sex-specific.
Collaborators in the Department of Neurosurgery and the Department of Neurology at Massachusetts General Hospital including Robert W. Regenhardt, MD, PhD, neuroendovascular fellow, Aman Patel, MD, director of Cerebrovascular and Endovascular Neurosurgery, Natalia S. Rost, MD, MPH, FAAN, chief of the Stroke Division, and Mark R. Etherton, MD, PhD, instructor in neurology, and colleagues present the data in the Journal of Neurology.
Methods
The team reviewed a prospectively maintained database and identified 381 consecutive patients with acute anterior-circulation ELVO who underwent EVT between January 2011 and September 2019. There were 193 women and 188 men.
Baseline Clinical Characteristics and Treatments
Compared with men, women were significantly:
- Older—median age 75 vs. 64 (P<0.0001)
- More likely to have pre-stroke disability, defined as a score of 2 to 4 on the modified Rankin scale (mRS)—17% vs. 9% (P=0.032)
- More likely to have atrial fibrillation—41% vs. 30% (P=0.033)
- Less likely to have cervical internal carotid artery (ICA) atherosclerosis, have coronary artery disease, or be current smokers
Median National Institutes of Health Stroke Scale (NIHSS) scores at admission were similar for men and women.
Treatment
53% of women and 59% of men received intravenous alteplase (P=0.353). Median time from last known well (LKW) to alteplase, LKW to groin and groin to recanalization were also similar for men and women.
Outcomes
All outcomes studied were statistically similar for men and women, although there was a trend toward higher mortality in women:
- Adequate reperfusion (Thrombolysis in Cerebral Infarction score 2b or 3)—78% of both cohorts
- Intracerebral hemorrhage—5% of women and 8% of men
- Functionally independent at 90 days (mRS ≤2)—39% and 44%
- Good outcome at 90 days (change from pre-stroke mRS ≤2)—49% and 50%
- 90-day mortality—27% vs. 18% (P=0.052)
Sex-Specific Determinants of Outcomes
This was the first study to examine sex-specific determinants of adequate reperfusion and functional outcomes. In multivariable models:
- Odds of adequate reperfusion—Cervical ICA atherosclerosis (OR, 0.315) and dissection (OR, 0.124) significantly decreased the odds in men but no factor was significant in women
- Odds of a good outcome at 90 days in men—Adequate reperfusion (OR, 4.920) increased the odds whereas older age (OR, 0.968), history of prior stroke or transient ischemic attack (OR, 0.258), higher NIHSS score (OR, 0.912) and ICH (OR, 0.111) reduced the odds
- Odds of a good outcome at 90 days in women—Adequate reperfusion (OR, 6.465) increased the odds whereas older age (OR, 0.968) and greater NIHSS score (OR, 0.884) reduced them
Pre-stroke disability did not independently decrease the odds of adequate reperfusion or a good outcome at 90 days.
Commentary
It can be concluded that EVT is efficacious for both men and women. Previous studies of sex differences included only patients treated in early time windows, and most were post hoc analyses of randomized controlled trials with multiple inclusion and exclusion criteria, which may limit their generalizability.
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