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

Challenges to Widespread Implementation of Stroke Thrombectomy

Endovascular treatment (EVT) for acute ischemic stroke is one of the most efficacious and effective treatments in medicine, yet globally, its implementation remains limited. Patterns of EVT underutilization exist in virtually any health care system and range from a complete lack of access to selective undertreatment of certain patient subgroups. In this review, we outline different patterns of EVT underutilization and possible causes. We discuss common challenges and bottlenecks that are encountered by physicians, patients, and other stakeholders when trying to establish and expand EVT services in different scenarios and possible pathways to overcome these challenges. Lastly, we discuss the importance of implementation research studies, strategic partnerships, and advocacy efforts to mitigate EVT underutilization.

Stroke

Stroke affects up to one in five people during their lifetime in some high-income countries, and up to almost one in two in low-income countries. Globally, it is the second leading cause of death. Clinically, the disease is characterised by sudden neurological deficits. Vascular aetiologies contribute to the most common causes of ischaemic stroke, including large artery disease, cardioembolism, and small vessel disease. Small vessel disease is also the most frequent cause of intracerebral haemorrhage, followed by macrovascular causes. For acute ischaemic stroke, multimodal CT or MRI reveal infarct core, ischaemic penumbra, and site of vascular occlusion. For intracerebral haemorrhage, neuroimaging identifies early radiological markers of haematoma expansion and probable underlying cause. For intravenous thrombolysis in ischaemic stroke, tenecteplase is now a safe and effective alternative to alteplase. In patients with strokes caused by large vessel occlusion, the indications for endovascular thrombectomy have been extended to include larger core infarcts and basilar artery occlusion, and the treatment time window has increased to up to 24 h from stroke onset. Regarding intracerebral haemorrhage, prompt delivery of bundled care consisting of immediate anticoagulation reversal, simultaneous blood pressure lowering, and prespecified stroke unit protocols can improve clinical outcomes. Guided by underlying stroke mechanisms, secondary prevention encompasses pharmacological, vascular, or endovascular interventions and lifestyle modifications.

The association of gender with functional outcome in thrombolysed stroke: A secondary analysis of INTRECIS study

Background and Purpose

Sex differences in acute ischemic stroke have been widely investigated, but the difference in acute ischemic stroke patients who received intravenous thrombolysis is not well understood. The current study was to investigate the issue based on a prospective cohort.

Methods

From the Intravenous Thrombolysis Registry for Chinese Ischemic Stroke within 4.5h onset (INTRECIS) cohort, a total of 953 eligible patients with acute ischemic stroke were enrolled in final analysis. Based on 3-month modified Rankin scale score (mRS), patients were classified into good outcome group (mRS 0-1) and poor outcome group (mRS 2-6). Univariate and multivariate logistic regression analyses were used to identify predictive factors for clinical outcome in male or female patients.

Results

Of the 953 patients treated with intravenous thrombolysis, 314 (32.9 %) were women. At day 90, we found no significant gender differences in good outcome (72.5 % vs 65.6 %, adjusted p = 0.414). We got the same results after propensity score matching (69.5 % vs 63.4 %, adjusted p = 0.637). Furthermore, we found that initial National Institute of Health Stroke Scale (NIHSS) score (odd ratio [OR] 0.877; 95 % CI 0.847-0.909, p < 0.001) and serum creatinine (OR 0.993; 95 % CI 0.986-1.000, p = 0 0.043) were found to be independent risk factors for poor outcome in male patients, while initial NIHSS score (OR 0.879; 95 % CI 0.839-0.920, p < 0.001), age (OR 0.970; 95 % CI 0.946-0.995, p = 0.017), systolic blood pressure (OR 0.984; 95 % CI 0.972-0.996, p = 0.007) and small artery occlusion (OR 2.718; 95 % CI 1.065-6.936, p = 0.036) in female patients.

Conclusions

In this study, we found no gender difference in clinical outcome of thrombolysed stroke patients, but a difference in risk factors predicting outcome in male vs female patients was identified for the first time.

Sex Differences in Outcomes after Endovascular Thrombectomy for Patients with Acute Ischemic Stroke

INTRODUCTION

Endovascular thrombectomy (EVT) is the standard of care for patients with large-vessel occlusion acute ischemic stroke (AIS). There may be differing recanalization effectiveness based on patients' sex, and understanding such variations can improve patient outcomes by adjusting for differences. We aimed to assess the sex differences in outcome after EVT for patients with AIS.

METHODS

We retrospectively analyzed 250 consecutive AIS patients who underwent EVT from July 2019 to February 2022 across two large comprehensive tertiary care stroke centers in China. Outcomes of male patients were compared to females, where poor outcome was defined as a modified Rankin score (mRS) of 3-6 at 90 days.

RESULTS

Male patients had higher rates of symptomatic intracranial hemorrhage (sICH) (12.50% vs. 4.05%, p = 0.042) and higher hospitalization costs (114,541.08 vs. 105,790.27 RMB, p = 0.024). Male patients also had a longer median onset-to-needle time (ONT) (146.00 [104.00, 202.00] versus 120.00 [99.25, 144.75], p = 0.026). However, there were no differences in hospitalization length (p = 0.251), 90-day favorable outcome (p = 0.952), and 90-day mortality (p = 0.931) between the sexes.

CONCLUSION

Female patients had lower hospitalization costs and sICH rates than males after EVT for AIS. Identifying such differences and implementing measures, including adaptations to workflow optimization, would help to reduce the ONT and last known normal-to-puncture time seen in males to improve patient outcomes. Despite such variations, favorable outcomes and mortality are similar in female and male AIS patients.

How Do Quantitative Tissue Imaging Outcomes in Acute Ischemic Stroke Relate to Clinical Outcomes?

BACKGROUND AND PURPOSE

Infarct volume and other imaging markers are increasingly used as surrogate measures for clinical outcome in acute ischemic stroke research, but how improvements in these imaging surrogates translate into better clinical outcomes is currently unclear. We investigated how changes in infarct volume at 24 hours alter the probability of achieving good clinical outcome (modified Rankin Scale [mRS] 0-2).

METHODS

Data are from endovascular thrombectomy patients from the randomized controlled ESCAPE-NA1 (Efficacy and Safety of Nerinetide for the Treatment of Acute Ischaemic Stroke) trial. Infarct volume at 24 hours was manually segmented on non-contrast computed tomography or diffusion-weighted magnetic resonance imaging. Probabilities of achieving good outcome based on infarct volume were obtained from a multivariable logistic regression model. The probability of good outcome was plotted against infarct volume using linear spline regression.

RESULTS

A total of 1,099 patients were included in the analysis (median final infarct volume 24.9 mL [interquartile range: 6.6-92.2]). The relationship between total infarct volume and good outcome probability was nearly linear for infarct volumes between 0 mL and 250 mL. In this range, a 10% increase in the probability of achieving mRS 0-2 required a decrease in infarct volume of approximately 34.0 mL (95% confidence interval: -32.5 to -35.6). At infarct volumes above 250 mL, the probability of achieving mRS 0-2 probability was near zero. The relationships of tissue-specific infarct volumes and parenchymal hemorrhage volume generally showed similar patterns, although variability was high.

CONCLUSION

There seems to be a near-linear association between total infarct volume and probability of achieving good outcome for infarcts up to 250 mL, whereas patients with infarct volumes greater than 250 mL are highly unlikely to have a favorable outcome.

Addressing Disparities in Acute Stroke Management and Prognosis

There are now abundant data demonstrating disparities in acute stroke management and prognosis; however, interventions to reduce these disparities remain limited. This special report aims to provide a critical review of the current landscape of disparities in acute stroke care and highlight opportunities to use implementation science to reduce disparities throughout the early care continuum. In the prehospital setting, stroke symptom recognition campaigns that have been successful in reducing prehospital delays used a multilevel approach to education, including mass media, culturally tailored community education, and professional education. The mobile stroke unit is an organizational intervention that has the potential to provide more equitable access to timely thrombolysis and thrombectomy treatments. In the hospital setting, interventions to address implicit biases among health care providers in acute stroke care decision-making are urgently needed as part of a multifaceted approach to advance stroke equity. Implementing stroke systems of care interventions, such as evidence-based stroke care protocols at designated stroke centers, can have a broader public health impact and may help reduce geographic, racial, and ethnic disparities in stroke care, although further research is needed. The long-term impact of disparities in acute stroke care cannot be underestimated. The consistent trend of longer time to treatment for Black and Hispanic people experiencing stroke has direct implications on long-term disability and independence after stroke. A learning health system model may help expedite the translation of evidence-based interventions into clinical practice to reduce disparities in stroke care.

Sex differences in outcomes of endovascular therapy for acute vertebrobasilar occlusion: data from ANGEL-ACT Registry

BACKGROUND

Understanding sex disparities in stroke can identify gaps in clinical care. The objective of this study was to investigate whether sex differences could influence clinical outcomes of patients with acute vertebrobasilar artery occlusion (VBAO) who underwent endovascular therapy (EVT).

METHODS

Patients were selected from the ANGEL-ACT Registry. The primary outcome was favorable functional outcome (90-day modified Rankin Scale [mRS] 0-3). Secondary outcomes included 90-day mRS distribution, excellent outcome (mRS 0-1), functional independence (mRS 0-2), early neurological improvement, recanalization, intracranial hemorrhage, and mortality within 90 days. The above outcomes were compared by two adjustment models, including (1) multivariable logistics analysis adjusting for all baseline and procedural variables with a P < 0.05; (2) adjusting for the propensity score.

RESULTS

There were 347 acute VBAO patients treated with EVT included, of whom 72 (20.7%) were women and 275 (79.3%) were men. Women were older (72[63-76] vs. 62[53-69], P < 0.001) and had a higher rate of atrial fibrillation (31.9% vs. 8.7%, P < 0.001), lower rates of underlying intracranial atherosclerotic disease (30.6% vs. 51.3%, P = 0.007), and tandem occlusion (8.3% vs. 21.8%, P = 0.009) than men. The rate of favorable outcome (mRS 0-3) was similar between women and men (41.7% vs. 51.3%, adjusted odds ratio 1.56, 95%CI: 0.83-2.95, P = 0.171). There were no sex differences in other clinical outcomes (all P > 0.05).

CONCLUSIONS

In the ANGEL-ACT registry, the percentage of men with acute VBAO undergoing EVT was approximately fourfold higher than that of women with acute VBAO undergoing EVT. Sex differences did not modify the outcomes of acute VBAO after EVT.

Trends of Sex Differences and Associated Factors in Stroke Outcomes Among Patients With Acute Ischemic Stroke: 2007 to 2018

BACKGROUND AND OBJECTIVES

Female patients have been shown to experience worse clinical outcomes after acute ischemic stroke (AIS) compared with male patients. We aimed to estimate the temporal trends in the sex differences in stroke outcomes and identify risk factors contributing to the sex differences spanning 10 years in China.

METHODS

This cohort study was conducted based on data from the China National Stroke Registries (CNSRs, comprising 3 phases, I-III, from 2007 to 2018). Patients with ischemic stroke within 7 days of symptom onset were included. The primary outcome was a 12-month poor functional outcome. Other outcomes included mortality and disability-adjusted life-year (DALY) lost. The sex differences in outcomes and associated factors were estimated using multivariable logistic regression. The sex differences between CNSRs were tested by the interaction of sex and time.

RESULTS

Among 42,564 patients included, 35.4% were female. The age-adjusted event rate of 12-month poor functional outcome and mortality decreased both in male and female patients after stroke onset (CNSRs I, II, and III, all p varies over time <0.001). There was a decrease in DALY lost for both sexes over the decade (male patients: from 10.1 to 9.3 DALYs; female patients: from 10.9 to 9.6 DALYs). Female patients showed worse 12-month poor functional outcome in CNSRs I and II (odds ratio [OR] with 95% CI: 1.24 [1.10-1.39] and 1.12 [1.01-1.25], respectively) compared with male patients, but the sex difference attenuated in CNSR III (OR with 95% CI: 1.02 [0.89-1.16]), with the temporal trend (p varies over time = 0.004). The sex difference and the temporal trend of the sex difference in mortality from 2007 to 2018 were not found (p varies over time = 0.45). The most important factors attenuating the sex difference in poor functional outcome in CNSRs I and III were education level, socioeconomic deprivation, baseline stroke severity, and current smoking.

DISCUSSION

This study demonstrated that the sex disparity in poor functional outcome at 12 months was substantially narrowed covering 10 years and completely attenuated in 2015-2018. The findings suggested that female patients have experienced larger improvements in stroke outcomes than male patients over the past decade.

Endovascular thrombectomy for basilar-artery occlusion: A meta-analysis with trial sequential analysis

Background and purpose

Basilar-artery occlusion (BAO) usually accounts for devastating neurologic sequelae, poor prognosis, and even death. While endovascular thrombectomy (EVT) is the most successful treatment for anterior circulation stroke with large vessel occlusion, its effectiveness in treating acute BAO is still debatable. Our aim is to compare the efficacy and safety between EVT and conservative medical treatment (CMT) in BAO.

Methods

Up until May 2022, relevant literature was gathered using searches in Embase, PubMed, and the Cochrane Library. The primary outcomes were defined as good functional outcome (modified Rankin Scale 0-2) and favorable functional outcome (modified Rankin Scale 0-3) at 3 months between EVT and CMT groups. The secondary outcomes included mortality at 3 months, symptomatic intracerebral hemorrhage (ICH), and any ICH.

Results

Eight studies involving 3733 patients with BAO were enrolled 2573 individuals underwent EVT, and the remaining 1160 patients received CMT. Compared with CMT, EVT achieved more favorable functional outcome (odds ratio (OR) 1.26, 95% CI 1.03-1.55, I2 = 54%, p = 0.05) in BAO. The good functional outcome showed a similar tendency (OR 1.23, 95% CI 0.97-1.57, I2 = 63%, p = 0.02) as well. EVT decreased mortality at 3 months (OR 0.81, 95% CI 0.70-0.93, I2 = 31 %, p = 0.19), although having a tendency to cause symptomatic ICH (OR 2.91, 95% CI 1.38-6.18, I2 = 22 %, p = 0.27).

Conclusions

EVT in BAO provides superior functional outcomes and less mortality compared with CMT. Even though EVT has the propensity to cause symptomatic ICH, EVT nevertheless improved posterior circulation stroke.

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-Related Differences in Outcomes of Endovascular Treatment for Anterior Circulation Large Vessel Occlusion

BACKGROUND

Sex disparities in acute large vessel occlusion (LVO) following endovascular treatment (EVT) have been recently reported. However, there is uncertainty about the effect of sex differences on functional outcomes after EVT, particularly in an Asian population. The present study aimed to compare the clinical and safety outcomes between men and women with anterior circulation LVO treated with EVT.

METHODS

We analyzed data from the ANGEL-ACT (Endovascular Treatment Key Technique and Emergency Work Flow Improvement of Acute Ischemic Stroke: a Prospective Multicenter Registry Study) Registry, which was conducted at 111 hospitals from 26 provinces in China between November 2017 and March 2019. Men and women with anterior circulation LVO treated with EVT were matched using propensity scores. After a 1:1 propensity score matching, we compared the clinical outcomes including 90-day ordinal modified Rankin Scale distribution (primary outcome), procedure duration, successful reperfusion, symptomatic intracranial hemorrhage, and mortality. Furthermore, we explored sex modification on the primary outcome in subgroup analysis.

RESULTS

Of 1321 patients, 483 (36.6%) were women and 838 (63.4%) were men. The mean age for women and men were 68 and 62 years old, respectively. Among 578 patients identified after matching, there were no sex differences (men versus women) in 90-day ordinal modified Rankin Scale distribution (median [interquartile range], 4 [1-5] versus 3 [1-5], P=0.464), successful reperfusion (86.5% versus 91.0%, P=0.089), symptomatic intracranial hemorrhage (6.5% versus 7.9%, P=0.512), and mortality within 90 days (17.7% versus 17.0%, P=0.826). However, men had a longer median procedure duration than women (86 [52-128] versus 72 [48-110] minutes, β=14.51, [95% CI, 4.19-24.84]; P=0.006). Subgroup analysis showed that in patients with National Institutes of Health Stroke Scale score <15, women tended to have a better outcome than men, whereas there was no gender effect in those with National Institutes of Health Stroke Scale score ≥15 (P for interaction=0.032).

CONCLUSIONS

Overall, this matched-control study from the ANGEL-ACT study showed similar clinical outcomes between men and women with anterior circulation LVO treated with EVT. However, in the subgroup of patients presenting with lower stroke severity (ie, National Institutes of Health Stroke Scale score <15), women tended to have a better outcome than men highlighting a potential sex disparity for further investigation.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03370939.

Sex differences in the utilization and outcomes of endovascular treatment after acute ischemic stroke: A systematic review and meta-analysis

Background

Studies of sex differences in the use and outcomes of endovascular treatment (EVT) for acute ischemic stroke report inconsistent results.

Methods

We systematically searched PubMed and Embase databases for studies examining sex-specific utilization of EVT for acute ischemic stroke published before 31 December 2021. Estimates were compared by study type: randomized clinical trials (RCTs) and non-RCTs (hospital-based, registry-based or administrative data). Random effects odds ratios (ORs) were generated to quantify sex differences in EVT use. To estimate sex differences in functional outcome on the modified Rankin scale after EVT, the female:male ratio of ORs and 95% confidence intervals (CIs) were obtained from ordinal or binary analysis.

Results

6,396 studies were identified through database searching, of which 594 qualified for a full review. A total of 51 studies (36 non-RCT and 15 RCTs) reporting on sex-specific utilization of EVT were included, and of those 10 estimated the sex differences of EVT on functional outcomes. EVT use was similar in women and men both in non-RCTs (OR: 1.03, 95% CI: 0.96-1.11) and RCTs (1.02, 95% CI: 0.89-1.16), with consistent results across years of publication and regions of study, except that in Europe EVT treatment was higher in women than men (1.15, 95% CI: 1.13-1.16). No sex differences were found in the functional outcome by either ordinal and binary analyses (ORs 0.95, 95% CI: 0.68-1.32] and 0.90, 95% CI: 0.65-1.25, respectively).

Conclusions

No sex differences in EVT utilization or on functional outcomes were evident after acute ischemic stroke from large-vessel occlusion. Further research may be required to examine sex differences in long-term outcomes, social domains, and quality of life.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=226100, identifier: CRD42021226100.

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.