Anusha Boyanpally, MD

Uchida K, Yoshimura S, Sakai N, Yamagami H, Morimoto T. Sex Differences in Management and Outcomes of Acute Ischemic Stroke With Large Vessel Occlusion. Stroke. 2019;50:1915–1918.

Although the incidence of acute ischemic strokes with large vessel occlusion (LVO) are identified more in males, sex disparities in clinical outcomes with endovascular therapy (EVT) were inconclusive. These authors have investigated sex disparities in patients with acute ischemic stroke with LVO treated with EVT in a prospective, multicenter RESCUE (Recovery by Endovascular Salvage for Cerebral Ultra-Acute Embolism)-Japan Registry 2 patient database.

A total of 2420 patients with acute ischemic stroke with LVO were enrolled in this study. The primary outcome was good outcome, defined as a modified Rankin Scale score of 0 to 2 at 90 days after onset. Secondary outcomes were mortality within 90 days, any or symptomatic intracranial hemorrhage within 72 hours after onset, and recurrence of stroke or transient ischemic attack within 90 days. Among 2399 patients, 1087 patients were female and 1312 were male; in those, 521 (47.9%) of females and 757 (57.7%) of males received EVT, respectively.

Good outcome was observed in 297 (27.3%) and 580 (44.2%) of the females and males, respectively (P<0.0001). Mortality was 12.3% and 9.9% in females and males, respectively. The study concluded that females with acute ischemic stroke with large vessel occlusion treated with EVT showed poor functional outcome compared to males. Also, females were less likely to receive EVT (p= <0.001), and older, lower utilization of EVT accounted for a portion of the poor outcome.

The study has included a good number of confounders to calculate adjusted odds ratio, which include age, National Institutes of Health Stroke Scale (NIHSS) score, Alberta Stroke Program Early CT Score (ASPECTS), creatinine values, location of occlusions, number of vessels involved, cause of stroke, history of stroke, time from onset to hospital door, and use of intravenous r-tPA. But symptomatic intracranial hemorrhage was defined as neurological worsening of >4 points on the NIHSS, which probably led to missing some of the patients with SICH with less than 4 difference in NIHSS.

In addition to lesser interventions in females, there were other factors which might have influenced the outcomes of the study. Female patients in this registry were older (p value <0.001), and NIHSS <16 were less in the female (43.5% vs 58.8%), OR 0.68 95 CI (0.51-0.91). More males have reached onset to door time within 360 minutes than females 77.5% vs 71.6% P=0.0012), which probably led to more EVT in the males. Males have received more rt-PA (56.8%) than females (37.6%), which also can have an impact on the outcomes. Male population had a better baseline function, and more ASPECT score which predicts better outcomes.

The authors did not consider stroke risk factors such as hypertension, diabetes, atrial fibrillation, smoking status, antiplatelets versus anticoagulants use, etc., and other co-morbidities such as heart failure. Also, there was no mention about the size of the infarct and if patients had a completed infarct, which could affect the eligibility of patients to receive endovascular intervention.

Despite the above limitations, this is an important study to emphasize sex disparities in the outcomes with LVO. The study has considered other important factors such as history of stroke, anterior vs posterior circulation strokes and cardioembolic strokes, which play an important role in predicting the prognosis. Interestingly, even after adjusting many risk factors, and confounders, poor outcomes were noted in the female cohort. Further studies are required to investigate and look for causes leading to poor outcomes in females with LVO receiving EVT.