Men, women equally benefit from endovascular treatment for stroke

Endovascular treatment (EVT) for ischaemic stroke produces improvements in functional outcome and other clinical, imaging and safety outcome measures. The treatment effect is similar between men and women, with the latter even having more years of healthy life, as shown in the results of two recent studies.

The first study used data from seven randomized controlled trials on EVT within the HERMES* collaboration and included 1,762 patients (47 percent women). Compared with men, women were older (median, 70 vs 66 years; p<0.001), were smoking less often (30 percent vs 44 percent; p<0.001) and had higher collateral grades (grade 3: 46 percent vs 35 percent; p<0.001).

Functional independence (modified Rankin Scale [mRS] score, 0–2) at 90 days, the primary outcome, did not differ significantly by sex (39 percent of men vs 39 percent of women). On ordinal logistic regression, EVT exerted a similar effect in women (adjusted common odds ratio [acOR], 2.13, 95 percent confidence interval [CI], 1.47–3.07) and men (acOR, 2.16, 95 percent CI, 1.59–2.96; p-interaction=0.926). [Stroke 2019;50:2413-2419]

Other outcomes were also comparable between women and men, as follows: mortality at 90 days (15 percent vs 16 percent, respectively), symptomatic intracranial haemorrhage (3.7 percent vs 3.6 percent) and successful reperfusion (75 percent vs 76 percent).

In light of the findings, lead investigator Dr Vicky Chalos from the Erasmus MC University Medical Center at Rotterdam, the Netherlands, pointed out that “sex does not influence clinical outcome after EVT for ischaemic stroke,” and that EVT benefits women as much as men.

“Sex should, therefore, not be a consideration in the selection of patients for EVT,” Chalos added.

Post-EVT optimal life advantage for women

In the second study, researchers went further by examining the effect of EVT on lifelong disability outcomes. “[B]ecause of differences in age of onset and poststroke mortality between the sexes, 90-day outcomes may be insufficient to characterize the differences in endovascular stroke thrombectomy outcome on poststroke disability, as they do not account for poststroke lifetime disability, which could be substantially different between males and females,” said principal researcher Dr Sunil Shet from the McGovern School of Medicine, University of Texas Health Science Center at Houston, Texas, US.

Shet and colleagues looked at 389 patients (55 percent female; median National Institutes of Health Stroke Scale [NIHSS], 17) treated with the Solitaire stent retriever in the combined SWIFT**, STAR⁺ and SWIFT PRIME⁺⁺ cohorts.

There were no sex-specific differences observed in terms of deficit severity (p=0.21), occlusion location (p=0.62), infarct extent (p=0.24), rate of substantial reperfusion (p=0.37) and onset to reperfusion time (p=0.46). Functional independence at 90 days was also similar between men and women (OR, 1.0, 95 percent CI, 0.6–1.6), even with the latter being older (69 vs 64 years; p<0.001) and having a higher rate of atrial fibrillation (45 percent vs 30 percent; p=0.002). [Stroke 2019;50:2420-2427]

However, results for disability-adjusted life year (DALY) outcomes, defined as DALYs gained to represent life expectancy and adjusted for age at presentation and stroke severity, were significantly different between the sexes. Women had about 2 more years of optimal life after EVT compared with men (10.6 vs 8.5 years; p<0.001).

“[F]emales treated with endovascular stroke thrombectomy … enjoyed a DALY advantage over males up to the age of late 80s,” Shet said.

Role of selection bias

In a linked commentary, Drs Bharti Manwani and Louise McCullough from the McGovern Medical School, University of Texas Health Science Center at Houston, Texas, US, pointed out that while EVT indeed yields higher DALYs in women than men, selection bias is likely a factor. [Stroke 2019;50:2285-2287]

“Women have worse premorbid function which seems to account for much of the higher mortality and poorer outcomes seen after stroke… The women in the Chalos et al article had a lower stroke severity than men, which may be because of selection of healthier women and underscores the importance of capturing prestroke mRS as a potential confounder to effect size,” Manwani and McCullough wrote.

“Certainly, it is clear that sex should not be considered a factor in determining eligibility for acute stroke intervention. However, elderly women may be excluded from some of our most efficacious interventions solely based on their poor prestroke functional status,” they added.

*Highly Effective Reperfusion Using Multiple Endovascular Devices

**Solitaire FR With the Intention for Thrombectomy

⁺Solitaire FR Thrombectomy for Acute Revascularization

⁺⁺Solitaire FR With the Intention for Thrombectomy as Primary Endovascular Treatment