Do Outcomes between Women and Men Differ after Endovascular Thrombectomy? A Meta-analysis

Sex differences in clot, vessel and tissue characteristics in patients with a large vessel occlusion treated with endovascular thrombectomy

INTRODUCTION

To improve our understanding of the relatively poor outcome after endovascular treatment (EVT) in women we assessed possible sex differences in baseline neuroimaging characteristics of acute ischemic stroke patients with large anterior vessel occlusion (LVO).

PATIENTS AND METHODS

We included all consecutive patients from the MR CLEAN Registry who underwent EVT between 2014 and 2017. On baseline non-contrast CT and CT angiography, we assessed clot location and clot burden score (CBS), vessel characteristics (presence of atherosclerosis, tortuosity, size, and collateral status), and tissue characteristics with the Alberta Stroke Program Early Computed Tomography Score (ASPECTS). Radiological outcome was assessed with the extended thrombolysis in cerebral infarction score (eTICI) and functional outcome with the modified Rankin Scale score (mRS) at 90 days. Sex-differences were assessed with multivariable regression analyses with adjustments for possible confounders.

RESULTS

3180 patients were included (median age 72 years, 48% women). Clots in women were less often located in the intracranial internal carotid artery (ICA) (25%vs 28%, odds ratio (OR) 0.85;95% confidence interval: 0.73-1.00). CBS was similar between sexes (median 6, IQR 4-8). Intracranial (aOR 0.73;95% CI:0.62-0.87) and extracranial (aOR 0.64;95% CI:0.43-0.95) atherosclerosis was less prevalent in women. Vessel tortuosity was more frequent in women in the cervical ICA (aOR 1.89;95% CI:1.39-2.57) and women more often had severe elongation of the aortic arch (aOR 1.38;95% CI:1.00-1.91). ICA radius was smaller in women (2.3vs 2.5 mm, mean difference 0.22;95% CI:0.09-0.35) while M1 radius was essentially equal (1.6vs 1.7 mm, mean difference 0.09;95% CI:-0.02-0.21). Women had better collateral status (⩾50% filling in 62%vs 53% in men, aOR 1.48;95% CI:1.29-1.70). Finally, ASPECT scores were equal between women and men (median 9 in both sexes, IQR 8-10vs 9-10). Reperfusion rates were similar between women and men (acOR 0.94;95% CI:0.83-1.07). However, women less often reached functional independence than men (34%vs 46%, aOR 0.68;95% CI:0.53-0.86).

DISCUSSION AND CONCLUSION

On baseline imaging of this Dutch Registry, men and women with LVO mainly differ in vessel characteristics such as atherosclerotic burden, extracranial vessel tortuosity, and collateral status. These sex differences do not result in different reperfusion rates and are, therefore, not likely to explain the worse functional outcome in women after EVT.

Sex differences in onset to hospital arrival time, prestroke disability, and clinical symptoms in patients with a large vessel occlusion: a MR CLEAN Registry substudy

BACKGROUND

Women have been reported to have worse outcomes after endovascular treatment (EVT), despite a similar treatment effect in non-clinical trial populations. We aimed to assess sex differences at hospital presentation with respect to workflow metrics, prestroke disability, and presenting clinical symptoms.

METHODS

We included consecutive patients from the Multicentre Randomised Controlled Trial of Endovascular Treatment for Acute Ischaemic Stroke in The Netherlands (MR CLEAN) Registry (2014-2018) who received EVT for anterior circulation large vessel occlusion (LVO). We assessed sex differences in workflow metrics, prestroke disability (modified Rankin Scale (mRS) score ≥1), and stroke severity and symptoms according to the National Institutes of Health Stroke Scale (NIHSS) score on hospital admission with logistic and linear regression analyses and calculated the adjusted OR (aOR).

RESULTS

We included 4872 patients (47.6% women). Compared with men, women were older (median age 76 vs 70 years) and less often achieved good functional outcome at 90 days (mRS ≤2: 35.2% vs 46.4%, aOR 0.70, 95% CI 0.60 to 0.82). Mean onset-to-door time was longer in women (2 hours 16 min vs 2 hours 7 min, adjusted delay 9 min, 95% CI 4 to 13). This delay contributed to longer onset-to-groin times (3 hours 26 min in women vs 3 hours 13 min in men, adjusted delay 13 min, 95% CI 9 to 17). Women more often had prestroke disability (mRS ≥1: 41.1% vs 29.1%, aOR 1.57, 95% CI 1.36 to 1.82). NIHSS on admission was essentially similar in men and women (mean 15±6 vs 15±6, NIHSS <10 vs ≥10, aOR 0.91, 95% CI 0.78 to 1.06). There were no clear sex differences in the occurrence of specific stroke symptoms.

CONCLUSION

Women with LVO had longer onset-to-door times and more often prestroke disability than men. Raising awareness of these differences at hospital presentation and investigating underlying causes may help to improve outcome after EVT in women.

Sex and hypertensive organ damage: stroke

Stroke is a common cause of death and disability in both men and women. Differences in the incidence, presenting features and outcome after stroke have been reported between men and women. The global lifetime risk of stroke of approximately 25% is similar in men and women, although in women, the first cardiovascular event is more likely to be stroke than in men. Concerningly, there are reports of underuse of some treatments in women, although these differences may be diminishing over time. In addition, there are specific clinical challenges that can arise in women with stroke, such as stroke in people taking hormonal therapy, and stroke during pregnancy and stroke in the post-partum period. This review will cover these areas highlighting important differences and areas for future research. We found there are important differences in incidence of stroke, which differ by age. Further, there is concerning evidence that some treatments such as intravenous thrombolysis are underused in women. While there may be some differences in the relative effectiveness of treatments such as antiplatelet therapy and blood pressure reduction between men and women, for most aspects of stroke care, benefit is clear in both men and women and the emphasis must be on more equitable access. There is limited evidence to inform decision making during pregnancy and the post-partum period, but guidelines now exist and further research is needed in these areas.

Differences between males and females following endovascular therapy for stroke: A systematic review and meta-analysis

BACKGROUND

Endovascular therapy (EVT) represents the standard of care for eligible patients with acute ischemic stroke (AIS) and large vessel occlusion. To better understand differences in baseline characteristics and outcomes between males and females following EVT, we conducted a systematic review and meta-analysis.

METHODS

We identified, using the Nested Knowledge AutoLit platform, prospective studies that reported 90-day outcomes in males and females treated with EVT for AIS. The primary outcome of interest was 90-day modified Rankin Scale (mRS) 0-2. Secondary outcome variables included mRS 0-1, symptomatic intracranial hemorrhage (sICH), thrombolysis in cerebral infarction (TICI) score 2b-3, and mortality. Using R software version 4.1.2, we calculated pooled odds ratios (ORs) and their corresponding 95% confidence intervals (CI).

RESULTS

We included 10 studies with 10,209 patients. There was no difference between males and females in rate of mRS 0-2 (OR= 1.16; 95% CI= 0.87-1.56; P-value= 0.316); however, after removing outliers, males had higher rates of mRS 0-2 (OR= 1.40; 95% CI= 1.19-1.66; P-value< 0.001). Similar results were reported for mRS 0-1 (OR= 1.21; 95% CI= 0.93-1.56; P-value= 0.15), after removing outliers (OR= 1.32; 95% CI= 1.17-1.50; P-value< 0.001). There was no difference between males and females in rate of sICH (OR= 0.89; 95% CI= 0.74-1.08; P-value= 0.246), mortality (OR= 0.88; 95% CI= 0.74-1.05; P-value= 0.15), or TICI 2b-3 (OR= 1.19; 95% CI= 0.85-1.67; P-value= 0.309).

CONCLUSIONS

Males tend to experience better outcomes following EVT for AIS, even in the setting of similar reperfusion. The mechanisms underlying this phenomenon remain unclear, and further research is warranted. EVT remains a safe and effective option for both males and females with AIS.

Sex Differences in Functional Outcomes Following Endovascular Treatment for Acute Ischemic Stroke

BACKGROUND

Sex disparities have been reported across many aspects of acute ischemic stroke (AIS) care; however, there is a relative paucity of research examining sex differences in outcomes following endovascular treatment (EVT). Some studies report worse functional independence for females following EVT. Few, if any of these studies account for differences in age, baseline function, and comorbidity burden. This retrospective cohort study aimed to assess for sex differences in functional outcomes following EVT by comparing 90-day modified Rankin Scale (mRS) of males and females while controlling for baseline function and comorbidity burden.

METHODS

Baseline demographic and clinical data, and stroke severity were compared for 230 consecutive patients undergoing EVT for AIS between October 2014 and July 2019 at a tertiary stroke centre in Toronto, Canada. Effect of sex on likelihood of functional independence post-EVT was assessed using regression analysis with and without correction for age, baseline mRS, and Charlson Comorbidity Index (CCI).

RESULTS

Females undergoing EVT for AIS were older (75 ± 13 vs. 66 ± 15, p < 0.0001), with worse clinical and functional baselines. Unadjusted, males were more functionally independent (90-day mRS < 3) [OR = 1.831, 95%CI 1.082-3.098]. After controlling for age, baseline mRS and CCI, there was no difference between groups [OR 1.21, 95%CI 0.61-2.37].

CONCLUSIONS

This study provides evidence that prior findings of sex disparities in function after EVT may be accounted for by differences in age, baseline clinical status and functional independence between males and females when a comprehensive measure of comorbidity burden is utilized.

Women and Ischemic Stroke

Although men are at higher risk of stroke throughout most of their lifespan, the incidence of stroke in women climbs with age, increasing after menopause and rising sharply after 85 years. This, combined with women's longer life expectancy, results in most of the stroke deaths occurring in women. In addition to accounting for a larger proportion of strokes, women may also suffer a survival disadvantage, which may be due to several factors. In many families, women are the primary caretakers. When they become disabled, there may be limited options to care for them. Others suggest that some of the disparities in stroke outcomes in women may be related to age, pre-stroke functional status, and comorbidities. Regardless of the cause, the increased disability and post-stroke care requirements of women, particularly in our aging population, highlight the importance of determining successful strategies for stroke prevention, acute stroke treatments, optimization of stroke rehabilitation, and effective secondary prevention measures in women.

Sex and Gender Differences in Stroke and Their Practical Implications in Acute Care

There are several controversies regarding the role of sex and gender in the pathophysiology and management of acute stroke. Assessing the role of sex, i.e., biological/pathophysiological factors, and gender, i.e., sociocultural factors, in isolation is often not possible since they are closely intertwined with each other. To complicate matters even more, the functional baseline status of women and men at the time of their first stroke is substantially different, whereby women have, on average, a poorer reported/ascertained baseline function compared to men. These differences in baseline variables account for a large part of the differences in post-stroke outcomes between women and men. Adjusting for these baseline differences is difficult, and in many cases, residual confounding cannot be excluded. Despite these obstacles, a better understanding of how patient sex and gender differences influence acute stroke and stroke care pathways is crucial to avoid biases and allow us to provide the best possible care for all acute stroke patients. Disregarding patient sex and gender on one hand and ignoring potential confounding factors in sex- and gender-stratified analyses on the other hand, may cause researchers to come to erroneous conclusions and physicians to provide suboptimal care. This review outlines sex- and gender-related factors in key aspects of acute stroke, including acute stroke epidemiology, diagnosis, access to care, treatment outcomes, and post-acute care. We also attempt to outline knowledge gaps, which deserve to be studied in further detail, and practical implications for physicians treating acute stroke patients in their daily practice.

Sex Differences in the Evaluation and Treatment of Stroke

There are differences in the prevalence and strength of risk factors in women, along with sex-specific risk factors such as pregnancy. Women have a higher lifetime risk of stroke compared to men, with worse outcomes including higher rates of death and disability. We have made strides in the identification of sex-specific risk factors but with the paucity of sex-specific end points in clinical trials, stroke treatment and research are hindered.

Toward a Better Understanding of Sex- and Gender-Related Differences in Endovascular Stroke Treatment: A Scientific Statement From the American Heart Association/American Stroke Association

There are many unknowns when it comes to the role of sex in the pathophysiology and management of acute ischemic stroke. This is particularly true for endovascular treatment (EVT). It has only recently been established as standard of care; therefore, data are even more scarce and conflicting compared with other areas of acute stroke. Assessing the role of sex and gender as isolated variables is challenging because they are closely intertwined with each other, as well as with patients' cultural, ethnic, and social backgrounds. Nevertheless, a better understanding of sex- and gender-related differences in EVT is important to develop strategies that can ultimately improve individualized outcome for both men and women. Disregarding patient sex and gender and pursuing a one-size-fits-all strategy may lead to suboptimal or even harmful treatment practices. This scientific statement is meant to outline knowledge gaps and unmet needs for future research on the role of sex and gender in EVT for acute ischemic stroke. It also provides a pragmatic road map for researchers who aim to investigate sex- and gender-related differences in EVT and for clinicians who wish to improve clinical care of their patients undergoing EVT by accounting for sex- and gender-specific factors. Although most EVT studies, including those that form the basis of this scientific statement, report patient sex rather than gender, open questions on gender-specific EVT differences are also discussed.

Sex differences in outcomes after mechanical thrombectomy for acute ischemic stroke in the 'real world': protocol for a systematic review and meta-analysis study

INTRODUCTION

Mechanical thrombectomy (MT) had been regarded as the first-line therapy for acute ischaemic stroke patients. The sex differences in post-MT treatment outcomes were analysed by randomised controlled trial (RCT) studies with inconsistent conclusions. We suggest the results from the real-world data may differ from RCT containing studies. Therefore, the sex difference in non-clinical trial populations needs to be clarified.

METHODS AND ANALYSIS

In order to obtain relative studies comprehensively, we will search the main document databases, consisting of Web of Science, Medline in Ovid, Embase in Ovid and Cochrane Library, and trials registers, including Clinical Trails register. The clinical outcomes of real-world studies published between January 2015 and March 2022 will be included. The assessment methods of bias risk will be performed according to study type. The inclusion of studies, evaluation of risk and publication bias, data extraction will be implemented by two reviewers, respectively. The primary outcomes include successful recanalisation and 90-day favourable outcome. Secondary outcomes include vascular complication, hospital-related complications, death during hospital stay and follow-up, and intracerebral haemorrhage. The risk bias of observational studies will be evaluated by Newcastle-Ottawa Scale. I² statistic will be used to perform the assessment of study heterogeneity.

ETHICS AND DISSEMINATION

With no need of ethics approval in this review, results in this review ground on public data. The results of the study will be eventually presented at international conferences or in a related journal.

PROSPERO REGISTRATION NUMBER

CRD42021242597.