Sex Differences in Long-Term Survival after a First Stroke with Intravenous Thrombolysis: Ebrictus Study

Sex Dimorphisms in Ischemic Stroke: From Experimental Studies to Clinic

Sex dimorphisms are important factors that influence the outcomes after ischemic stroke, which include basic health status, cerebrovascular anatomy, hormone levels, and unique factors such as pregnancy and menopause. It is widely recognized that male and female respond differently to stroke. Women aged 45–74 years old showed a lower risk of stroke incidence compared to age-matched man. This kind of protection is lost with aging. Hence, there is increasing requirement to get a more comprehensive understanding of sex-based factors to stroke on stroke incidence, symptoms, and treatments. This review focuses on sex-specific mechanisms in response to stroke based on experimental studies and highlights recent findings in clinical studies including sex-differential evaluation and outcomes of stroke. Sex-based personalized medicine should be promising in stroke therapies.

Sex differences in IV thrombolysis treatment for acute ischemic stroke

Objective

A prior meta-analysis of reports published between 2000 and 2008 found that women were 30% less likely to receive IV recombinant tissue plasminogen activator (rtPA) treatment for stroke than men; we updated this meta-analysis to determine if this sex difference persisted.

Methods

We identified studies that reported sex-specific IV rtPA treatment rates for acute ischemic stroke published between 2008 and 2018. Eligible studies included representative populations of patients with ischemic stroke from hospital-based, registry-based, or administrative data. Random effects odds ratios (ORs) were generated to quantify sex differences.

Results

Twenty-four eligible studies were identified during this 10-year period. The summary unadjusted OR based on 17 studies with data on all ischemic stroke patients was 0.87 (95% confidence interval [CI], 0.82–0.93), indicating that women had 13% lower odds of receiving IV rtPA treatment than men. However, substantial between-study variability existed. Lower treatment odds in women were also observed in 7 studies that provided data on the subgroup of patients eligible for IV rtPA treatment, although the summary OR of 0.95 (95% CI, 0.88–1.02) was not statistically significant. Examination of time trends across 33 studies published between 2000 and 2018 found evidence that the sex difference had narrowed in more recent years.

Conclusions

Although there is considerable variability in the findings of individual studies, pooled data from recent studies show that women with acute stroke are less likely to be treated with IV thrombolysis compared with men. However, the size of this difference has narrowed compared to studies published before 2008.

Lack of Correlation Between Intracranial Carotid Artery Modified Woodcock Calcification Score and Prognosis of Patients With Acute Ischemic Stroke After Intravenous Thrombolysis

There have been few studies about the association between intracranial carotid artery calcification (ICAC) and acute ischemic stroke (AIS) prognosis after intravenous thrombolysis (IVT). We aimed to analyze the association between ICAC and prognosis (including symptomatic intracranial hemorrhage (sICH), functional outcome and death) of AIS patients treated with IVT. In this retrospective study, we consecutively included 232 AIS patients treated with IVT between April 2012 and December 2018. ICAC was evaluated using the modified Woodcock calcification visual score on non-enhanced cranial computed tomography scans. Poor functional outcome was defined as a modified Rankin Scale score > 2 at 3 months. We found that the modified Woodcock calcification score was associated with ICH, poor outcome, and death in univariable analyses on the symptomatic side and/or bilaterally. However, after adjustment for other different covariates, the results showed no significant difference. We documented that the presence and severity of ICAC did not significantly modify the beneficial effects of rtPA treatment in AIS.

Long-Term Survival After Stroke According to Reperfusion Therapy, Cardiovascular Therapy and Gender

BACKGROUND

A wide variety of factors influence stroke prognosis, including age, stroke severity and comorbid conditions; but most current information about outcomes and safety is derived from patients at 3 - 12 months and mostly coming from the hospital activity. The aim of this study is to evaluate whether treatment strategies have a differential impact on long-survival after acute ischemic stroke among men versus women.

METHODS

Acute ischemic stroke patients identified from the population-based register between January 1, 2011 and December 31, 2012 were included, and they were classified into: 1) Acute ischemic stroke + intravenous thrombolysis (group I); 2) Acute ischemic stroke + mechanical thrombectomy with or without intravenous thrombolysis (group II); 3) Acute ischemic stroke + medical therapy alone (no reperfusion therapies) (group III). Follow-up went through up until December 2016. The probability of survival was estimated by the Kaplan-Meier method, and the hazard ratio was obtained by using the Cox proportional hazard regression models. Mortality was interpreted as overall mortality.

RESULTS

A total of 14,368 cases (men 50.1%), 77.1 ± 11.0 years old were included. There was higher survival among those treated with intravenous thrombolysis (P < 0.001); women treated with thrombectomy (P < 0.001); and women < 80 years old without reperfusion therapy. The most common medications were antiplatelets (52.8%), associated with lower survival (P < 0.001); and statins (46.5%), associated with higher survival. The regression model produced the following independent outcome variables associated to mortality: anticoagulant hazard ratio (HR) 1.53 (95% confidence interval (95% CI): 1.44 - 1.63, P < 0.001), diuretics HR 1.71 (95% CI: 1.63 - 1.79, P < 0.001), antiplatelet HR 1.49 (95% CI: 1.42 - 1.56, P < 0.001), statins HR 0.73 (95% CI: 0.70 - 0.77; P < 0.001), angiotensin II receptor antagonists HR 0.93 (95% CI: 0.89 - 0.98, P = 0.008) and reperfusion therapy HR 0.88 (95% CI: 0.81 - 0.97, P = 0.009).

CONCLUSIONS

Men and women have different prognoses after revascularization treatment for acute ischemic stroke. Under 80 years old the women appear to have a better outcome than men when treated with thrombolysis therapy and/or catheter-based thrombectomy. The chronic cardiovascular pharmacotherapy must be evaluated whether they should be included as factors in the decision to reperfusion.

Sex differences in ischaemic stroke: potential cellular mechanisms

Stroke remains a leading cause of mortality and disability worldwide. More women than men have strokes each year, in part because women live longer. Women have poorer functional outcomes, are more likely to need nursing home care and have higher rates of recurrent stroke compared with men. Despite continued advancements in primary prevention, innovative acute therapies and ongoing developments in neurorehabilitation, stroke incidence and mortality continue to increase due to the aging of the U.S.

POPULATION

Sex chromosomes (XX compared with XY), sex hormones (oestrogen and androgen), epigenetic regulation and environmental factors all contribute to sex differences. Ischaemic sensitivity varies over the lifespan, with females having an "ischaemia resistant" phenotype that wanes after menopause, which has recently been modelled in the laboratory. Pharmacological therapies for acute ischaemic stroke are limited. The only pharmacological treatment for stroke approved by the Food and Drug Administration (FDA) is tissue plasminogen activator (tPA), which must be used within hours of stroke onset and has a number of contraindications. Pre-clinical studies have identified a number of potentially efficacious neuroprotective agents; however, nothing has been effectively translated into therapy in clinical practice. This may be due, in part, to the overwhelming use of young male rodents in pre-clinical research, as well as lack of sex-specific design and analysis in clinical trials. The review will summarize the current clinical evidence for sex differences in ischaemic stroke, and will discuss sex differences in the cellular mechanisms of acute ischaemic injury, highlighting cell death and immune/inflammatory pathways that may contribute to these clinical differences.