Female sex as an independent risk factor for stroke in atrial fibrillation: possible mechanisms

A systematic review and meta-analysis of differences between men and women in short-term outcomes following coronary artery bypass graft surgery

We provide an update regarding the differences between men and women in short-term postoperative mortality after coronary artery bypass grafting (CABG) and highlight the differences in postoperative risk of stroke, myocardial infarction, and new onset atrial fibrillation. We included 23 studies, with a total of 3,971,267 patients (70.7% men, 29.3% women), and provided results for groups of unbalanced studies and propensity matched studies. For short-term mortality, the pooled odds ratio (OR) from unbalanced studies was 1.71 (with 95% CI 1.69-1.74, I2 = 0%, p = 0.7), and from propensity matched studies was 1.32 (95% CI 1.14-1.52, I2 = 76%, p < 0.01). For postoperative stroke, the pooled effects were OR = 1.50 (95% CI 1.35-1.66, I2 = 83%, p < 0.01) and OR = 1.31 (95% CI 1.02-1.67, I2 = 81%, p < 0.01). For myocardial infarction, the pooled effects were OR = 1.09 (95% CI = 0.78-1.53, I2 = 70%, p < 0.01) and OR = 1.03 (95% CI = 0.86-1.24, I2 = 43%, p = 0.18). For postoperative atrial fibrillation, the pooled effect from unbalanced studies was OR = 0.89 (95% CI = 0.82-0.96, I2 = 34%, p = 0.18). The short-term mortality risk after CABG is higher in women, compared to men. Women are at higher risk of postoperative stroke. There is no significant difference in the likelihood of postoperative myocardial infarction in women compared to men. Men are at higher risk of postoperative atrial fibrillation after CABG.

Female "Paradox" in Atrial Fibrillation-Role of Left Truncation Due to Competing Risks

Female sex in patients with atrial fibrillation (AF) is a controversial and paradoxical risk factor for stroke-controversial because it increases the risk of stroke only among older women of some ethnicities and paradoxical because it appears to contradict male predominance in cardiovascular diseases. However, the underlying mechanism remains unclear. We conducted simulations to examine the hypothesis that this sex difference is generated non-causally through left truncation due to competing risks (CR) such as coronary artery diseases, which occur more frequently among men than among women and share common unobserved causes with stroke. We modeled the hazards of stroke and CR with correlated heterogeneous risk. We assumed that some people died of CR before AF diagnosis and calculated the hazard ratio of female sex in the left-truncated AF population. In this situation, female sex became a risk factor for stroke in the absence of causal roles. The hazard ratio was attenuated in young populations without left truncation and in populations with low CR and high stroke incidence, which is consistent with real-world observations. This study demonstrated that spurious risk factors can be identified through left truncation due to correlated CR. Female sex in patients with AF may be a paradoxical risk factor for stroke.

Thrombodynamics Test in Assessing the Risk of Thrombus Formation in Patients with Atrial Fibrillation Taking Direct Oral Anticoagulants

Aim. To evaluate thrombus characteristics in patients with atrial fibrillation (AF) taking different direct oral anticoagulants (DOACs) using Thrombodynamics test.Materials and methods. Thrombodynamics test was performed in 100 patients with paroxysmal and permanent forms of AF taking different DOACs, dose choice was done in accordance with the instructions for drugs use. For analysis samples of fresh citrated platelet-free plasma were taken just before regular DOACs dose intake (trough concentration). Statistical data processing was carried out using R software packages.Results. All patients had no history of thrombosis or bleeding before inclusion in this study. All parameters of Thrombodynamics test taken at residual concentration of DOACs were in general within reference values, that is in the area of normal coagulation: spatial clot growth rate (V) – 26.56 (25.0; 29.2) μm/min, the time to the start of clot growth (Tlag) – 1.05 (0.85; 1.27) min, initial spatial clot growth rate (Vi) – 44.3±7.7 μm/min, stationary spatial clot growth rate (Vst) – 26.5 (24.9; 28.4) μm/min, clot size (CS) – 999.7 (912.9; 1084.7) μm, clot density (D) – 22883.1±3199.9 arb. units. D was appeared to be higher in women [22947.7 (21477.5; 22947.7) vs men [22124.8 (19722.8; 22124.8), p=0.035] and Tlag was significantly higher in patients with chronic heart failure [1.2 (1.0; 1.2) vs 1.0 (0.8; 1.0), p=0.008]. A correlation was found between level of creatinine and Tlag parameter, glomerular filtration rate (GFR) and clot density. With an increase in the level of creatinine in the blood and a decrease in GFR, respectively, there was an increase in Tlag parameter (p-value 0.038); with an increase in GFR, clot density decrease (p-value 0.005).

Conclusion. All parameters of Thrombodynamics test on residual concentration of DOACs were within reference values that indicated optimal anticoagulant effect of all DOACs. The obtained data of normal coagulation at the residual concentration of the anticoagulant are consistent with the previously obtained data on the safety and effectiveness of DOACs using other methods. Further studies with clinical end points are needed to assess the clinical value of this method.

Changes in fibrinolytic activity and coagulation factors after epicardial left atrial appendage closure in patients with atrial fibrillation

BACKGROUND

The left atrial appendage (LAA) is known to be the primary source of thrombus formation in atrial fibrillation (AF). We investigate whether epicardial LAA occlusion (LAAO) from the cardiovascular system has an effect on coagulation and prothrombotic status in AF.

METHODS

Twenty-two patients with nonvalvular AF, who were not currently receiving oral anticoagulation (OAC) therapy, participated in a single-center prospective study. We measured fibrinogen and plasminogen levels along with plasma fibrin clot permeability, clot lysis time (CLT) and endogenous thrombin potential (ETP) before the LAAO procedure, at discharge and 1 month afterward.

RESULTS

One month after the LAAO procedure, plasma fibrin clot permeability improved by 39.3% as measured by clots prepared from peripheral blood (P=0.019) and also after adjustment for fibrinogen (P=0.027). Higher plasma fibrin clot permeability was associated with improved clot susceptibility to lysis (r=-0.67, P=0.013). CLT was reduced by 10.3% (P=0.0020), plasminogen activator inhibitor-1 antigen levels were reduced by 52% (P=0.023) and plasminogen activity was increased by 8.9% (P=0.0077). A trend toward decreased thrombin generation, reflected by a decreased ETP and peak thrombin generated was also observed 1 month after LAAO procedure (P=0.072 and P=0.087, respectively). No differences were observed in tissue-type plasminogen activator and thrombin-activatable fibrinolysis inhibitor plasma levels (both P>0.05).

CONCLUSIONS

Obtained results seem to confirm that LAA plays a key role in thrombogenesis. Elimination of LAA from the circulatory system may improve fibrin clot permeability and susceptibility to fibrinolysis in peripheral blood.

Thromboembolic Events Detected by Diffusion-Weighted Magnetic Resonance Imaging after Flow Diverter Treatment: The Impact of Procedure Time

BACKGROUND

Periprocedural thromboembolism is a serious complication of endovascular treatment for intracranial aneurysms. In addition to symptomatic ischemia, asymptomatic postprocedural diffusion-weighted image-positive lesions (DPLs) are considered important. However, few studies have reported significant risk factors associated with DPLs and symptomatic ischemic stroke after flow diverter (FD) treatment. This study aimed to investigate the frequency and risk factors associated with DPLs after FD treatment.

METHODS

Between November 2015 and December 2021, 84 patients harboring 85 untreated, unruptured intracranial aneurysms treated with FD were enrolled.

RESULTS

DPLs after FD treatment were confirmed in 74 patients (87.1%), among whom 69 (93.2%) were clinically asymptomatic. In the univariate analyses, age >55 years (P = 0.040), smoking (P = 0.023), preprocedural P2Y12 reaction unit value of >185 (P = 0.030), larger dome size of >9.3 mm (P = 0.013), and prolonged procedure time >80 minutes (P < 0.001) were significantly associated with postprocedural DPLs. In the multiple logistic regression model, only prolonged procedure time >80 minutes (odds ratio, 10.72; 95% confidence interval, 1.346-233.899; P = 0.023) was statistically significant. The mediator effect showed that the association between procedure time and the occurrence of DPLs was not significantly modified by any other factors, although only adjunctive coiling showed a tendency (P-value for interaction = 0.070).

CONCLUSIONS

Prolonged procedure time >80 minutes was the only identifiable factor related to postprocedural DPLs. Adjunctive coiling tended to mediate the effects of a prolonged procedure time on the occurrence of DPLs after FD treatment.

Incidence and Determinants of Spontaneous Cardioversion of Early Onset Symptomatic Atrial Fibrillation

Atrial fibrillation (AF) is the most frequent chronic arrhythmia worldwide, and it is associated with significant morbidity and mortality, making it a considerable burden both to patients and the healthcare system. Nowadays, an early attempt to restore sinus rhythm in acute symptomatic AF through electrical or pharmacological cardioversion is the most common approach in the Emergency Department (ED). However, considering the high percentage of spontaneous cardioversion of paroxysmal AF reported by many studies, this approach may not be the ideal choice for all patients. In this manuscript we performed a review of the most relevant studies found in literature with the aim of identifying the main determinants of spontaneous cardioversion, focusing on those easy to detect in the ED. We have found that the most relevant predictors of spontaneous cardioversion are the absence of Heart Failure (HF), a small atrial size, recent-onset AF, rapid Atrial Fibrillatory Rate and the relationship between a previous AF episode and Heart Rate/Blood Pressure. A number of those are utilized, along with other easily determined parameters, in the recently developed "ReSinus" score which predicts the likelihood of AF spontaneous cardioversion. Such identification may help the physician decide whether immediate cardioversion is necessary, or whether to adopt a "watch-and-wait" strategy in the presence of spontaneous cardioversion determinants.

Sex differences of vascular brain lesions in patients with atrial fibrillation

Objective

To examine sex differences in prevalence, volume and distribution of vascular brain lesions on MRI among patients with atrial fibrillation (AF).

Methods

In this cross-sectional analysis, we included 1743 patients with AF (27% women) from the multicentre Swiss Atrial Fibrillation study (SWISS-AF) with available baseline brain MRI. We compared presence and total volume of large non-cortical or cortical infarcts (LNCCIs), small non-cortical infarcts, microbleeds (MB) and white matter hyperintensities (WMH, Fazekas score ≥2 for moderate or severe degree) between men and women with multivariable logistic regression. We generated voxel-based probability maps to assess the anatomical distribution of lesions.

Results

We found no strong evidence for an association of female sex with the prevalence of all ischaemic infarcts (LNCCI and SNCI combined; adjusted OR 0.86, 95% CI 0.67 to 1.09, p=0.22), MB (adjusted OR 0.91, 95% CI 0.68 to 1.21, p=0.52) and moderate or severe WMH (adjusted OR 1.15, 95% CI 0.90 to 1.48, p=0.27). However, total WMH volume was 17% larger among women than men (multivariable adjusted multiplicative effect 1.17, 95% CI 1.01 to 1.35; p=0.04). Lesion probability maps showed a right hemispheric preponderance of ischaemic infarcts in both men and women, while WMH were distributed symmetrically.

Conclusion

Women had higher white matter disease burden than men, while volume and prevalence of other lesions did not differ. Our findings highlight the importance of controlling risk factors for cerebral small vessel disease in patients with AF, especially among women.

Sex differences on outcomes following left atrial appendage occlusion in atrial fibrillation: A systematic review and meta-analysis

There is a lack of sufficient data on sex-related differences in outcomes of nonvalvular atrial fibrillation (AF) patients following left atrial appendage occlusion (LAAO). We conducted a meta-analysis to investigate the procedural complications and long-term outcomes after LAAO in women versus men. We screened Medline, EMBASE, Cochrane Center Register of Controlled Trials, and Clinical Trials.gov. The inclusion criteria were studies targeting the sex-related differences in outcomes in nonvalvular AF patients treated by LAAO. Procedural endpoints of interest included success rate, pericardial complications, major bleeding, and vascular complications during hospitalization. Long-term outcomes included all-cause mortality and ischemic stroke during follow-up. Studies that merely considered sex in the subgroup analysis were not included. Six observational studies with a total of 64,035 patients were identified. The procedural success rates did not differ between sexes (odds ratio [OR]: 0.98, 95% confidence interval [CI]: 0.89-1.09, p = 0.77), while women experienced more pericardial complications (OR: 1.78, 95% CI: 1.58-2.01, p < 0.00001), major bleedings (OR: 2.04, 95% CI: 1.75-2.39, p < 0.00001), and vascular complications (OR: 1.75, 95% CI: 1.41-2.17, p < 0.00001) than men. The sensitivity analysis performed by removing the largest study showed good stability. The long-term mortality and stroke rates did not differ between women and men in either the 1-year subgroup or the 2-year subgroup. In conclusion, despite comparable procedural success rates, women have a significantly higher incidence of pericardial complications, major bleeding, and vascular complications following LAAO. The long-term mortality and stroke rates do not differ between the sexes.

Arrhythmias in Female Patients: Incidence, Presentation and Management

There is a growing appreciation for differences in epidemiology, treatment, and outcomes of cardiovascular conditions by sex. Historically, cardiovascular clinical trials have under-represented females, but findings have nonetheless been applied to clinical care in a sex-agnostic manner. Thus, much of the collective knowledge about sex-specific cardiovascular outcomes result from post hoc and secondary analyses. In some cases, these investigations have revealed important sex-based differences with implications for optimizing care for female patients with arrhythmias. This review explores the available evidence related to cardiac arrhythmia care among females, with emphasis on areas in which important sex differences are known or suggested. Considerations related to improving female enrollment in clinical trials as a way to establish more robust clinical evidence for the treatment of females are discussed. Areas of remaining evidence gaps are provided, and recommendations for areas of future research and specific action items are suggested. The overarching goal is to improve appreciation for sex-based differences in cardiac arrhythmia care as 1 component of a comprehensive plan to optimize arrhythmia care for all patients.

Sex-Related Differences in Atrial Remodeling in Patients With Atrial Fibrillation: Relationship to Ablation Outcomes

BACKGROUND

Population studies have demonstrated a range of sex differences including a higher prevalence of atrial fibrillation (AF) in men and a higher risk of AF recurrence in women. However, the underlying reasons for this higher recurrence are unknown. This study evaluated whether sex-based electrophysiological substrate differences exist to account for worse AF ablation outcomes in women.

METHODS

High-density electroanatomic mapping of the left atrium was performed in 116 consecutive patients with AF. Regional analysis was performed across 6 left atrium segments. High-density maps were created using a multipolar catheter (Biosense Webster) during distal coronary sinus pacing at 600 and 300 ms. Mean voltage and conduction velocity was determined. Complex fractionated signals and double potentials were manually annotated.

RESULTS

Overall, 42 (36%) were female, mean age was 61±8 years and AF was persistent in 52%. Global mean voltage was significantly lower in females compared with males at 600 ms (1.46±0.17 versus 1.84±0.15 mV, P<0.001) and 300 ms (1.27±0.18 versus 1.57±0.18 mV, P=0.013) pacing. These differences were seen uniformly across the left atrium. Females demonstrated significant conduction velocity slowing (34.9±6.1 versus 44.1±6.9 cm/s, P=0.002) and greater proportion of complex fractionated signals (9.9±1.7% versus 6.0±1.7%, P=0.014). After a median follow-up of 22 months (Q1-Q3: 15-29), females had significantly lower single-procedure (22 [54%] versus 54 [75%], P=0.029) and multiprocedure (24 [59%] versus 60 [83%], P=0.005) arrhythmia-free survival. Female sex and persistent AF were independent predictors of single and multiprocedure arrhythmia recurrence.

CONCLUSIONS

Female patients demonstrated more advanced atrial remodeling on high-density electroanatomic mapping and greater post-AF ablation arrhythmia recurrence compared with males. These changes may contribute to sex-based differences in the clinical course of females with AF and in part explain the higher risk of recurrence.

Sex differences in the clinical outcomes after left atrial appendage closure: A systematic review and meta-analysis

INTRODUCTION

Left atrial appendage occlusion (LAAO) has emerged as a reasonable alternative to oral anticoagulation in a selective group of patients with atrial fibrillation (AF). While women are known have higher risk of AF-related stroke, the impact of sex differences on the clinical outcomes of LAAO has not been well studied.

OBJECTIVE

We sought to perform a meta-analysis evaluating sex differences on the outcomes of patients undergoing LAAO.

METHODS

We searched PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov databases (from inception to October 2021) for studies evaluating the impact of sex difference on LAAO procedural outcomes. We used a random-effect model to calculate risk ratio (RR) with 95% confidence intervals (CI). In-hospital all-cause mortality and ischemic stroke were the primary endpoints. In-hospital pericardial effusion/cardiac tamponade, major bleeding, technical success, device related thrombus and hospital length of stay were secondary outcomes.

RESULTS

A total of 5 studies with 54,754 patients were included, of which 22,461 (41%) were females. Female sex was associated with higher rates of in-hospital all-cause mortality (RR 2.18; 95% CI 1.46-3.26; P = 0.0001) and in-hospital ischemic stroke (RR 1.67; 95% CI 1.06-2.61; P = 0.03) when compared with males. Females had higher rates of in-hospital major bleeding (RR 1.93; 95% CI 1.40-2.67; P < 0.0001) and hospital length of stay >1 day (RR 1.38; 95% CI 1.33-1.45; P < 0.00001). There was no differences between females and males in terms of technical success and device related thrombus (RR 1.00; 95% CI 1.00-1.00; P = 1.00) and (RR 0.94, 95% CI 0.31-2.82; P = 0.91), respectively.

CONCLUSION

In conclusion, women are more likely to experience worse periprocedural outcomes with longer hospital stay after LAA closure. Further efforts are needed to increase the participation of women in clinical studies and to assess these differences to properly address the discrepancy in outcomes between men and women.

Decreased estimated glomerular filtration rate predicts long-term recurrence after catheter ablation of atrial fibrillation in mild to moderate renal insufficiency

BACKGROUND

Catheter ablation is an established therapy for atrial fibrillation (AF), but recurrence after ablation remains a great challenge. Additionally, little is known about the effect of renal function on the efficiency of AF ablation. This study aimed to evaluate the predictors of the prognosis of catheter ablation for AF, especially the effect of renal function.

METHODS

A total of 306 drug-refractory symptomatic patients with AF who underwent first-time catheter ablation were enrolled in the present study. Individuals underwent circumferential pulmonary vein isolation for paroxysmal AF and stepwise ablation for persistent AF.

RESULTS

The follow-up time was 27.2 ± 19.5 months, 202 patients (66.01%) were free of atrial tachyarrhythmia (non-recurrence group), and the other 104 patients experienced recurrence (recurrence group). The recurrence group had a larger left atrial diameter (LAD) and left atrial volume (LAV), a higher LAV index (LAVI) (both, p < 0.01), and a lower estimated glomerular filtration rate (eGFR) (53.5 ± 14.4 vs. 65.5 ± 13.3 ml/min/1.732, p < 0.001) and creatinine clearance rate (CCr) (85.2 ± 26.1 vs. 101.5 ± 29.4 ml/min, p < 0.05). Multivariate logistic regression indicated both eGFR (p = 0.002) and LAVI (p < 0.001) as independent associated factors for long-term recurrence after single catheter ablation; multivariate Cox proportional hazard regression with backward feature selection identified both eGFR (HR: 0.93, 95% CI: 0.91-0.95, p < 0.001) and LAVI (HR: 1.32, 95% CI: 1.25-1.40, p < 0.001) as independent prognostic factors for recurrence when adjusting other clinical variables.

CONCLUSIONS

Decreased eGFR and elevated LAVI may facilitate the long-term recurrence of atrial tachyarrhythmia after catheter ablation for AF.

Racial and Sex Disparities in Anticoagulation After Electrical Cardioversion for Atrial Fibrillation and Flutter

Background Anticoagulation is indicated for 4 weeks after cardioversion in patients with atrial fibrillation/flutter. We sought to examine whether there is evidence of sex or racial disparity in anticoagulant prescription following cardioversion, and whether postcardioversion anticoagulation affects outcomes. Methods and Results We identified a representative sample of Medicare patients who underwent elective electric cardioversion in an outpatient setting from 2015 to 2017. We identified patients who had an anticoagulant prescription for 3 months after the cardioversion date. Multivariable logistic regression was used to assess factors associated with a prescription of an anticoagulant after cardioversion. Cox regression analysis was used to test association of anticoagulation with a composite end point of 90-day mortality, ischemic stroke, or arterial embolism. The final study cohort included 7860 patients. Overall, 5510 patients (70.1%) received any anticoagulation following cardioversion, while 2350 (29.9%) did not. Patients who did not receive anticoagulation were younger, with a lower burden of most comorbidities. Patients were less likely to receive anticoagulation if they had dementia or atrial flutter, while patients with valvular heart disease, obesity, heart failure, peripheral vascular or coronary disease, or hypertension were more likely to receive anticoagulation. Female sex (adjusted odds ratio, 0.84; 95% CI, 0.75-0.92; P<0.001), Black and Hispanic race (adjusted odds ratio, 0.50; 95% CI, 0.38-0.65; and odds ratio, 0.56; 95% CI, 0.41-0.75, respectively; P<0.001) were independently associated with lower probability of anticoagulant prescription. Postcardioversion anticoagulation was associated with lower risk of the composite end point (adjusted hazard ratio, 0.38; 95% CI, 0.27-0.52; P<0.001). Conclusions Racial and sex disparities exist in anticoagulant prescription after outpatient elective cardioversion for atrial fibrillation.

Gender difference in left atrial appendage occlusion outcomes: Results from the Amplatzer™ Amulet™ Observational Study

Background

Percutaneous LAAO represents an alternative for stroke prevention in patients not tolerating anticoagulation. While women are at higher risk of complications during percutaneous coronary or valvular interventions, the impact of gender on LAAO outcomes is not well characterized. The current study assessed potential gender-related differences in procedural and long-term outcomes following left atrial appendage occlusion (LAAO).

Methods

1088 AF patients were enrolled in the prospective, multicenter, Amplatzer™ Amulet™ Observational Study and followed for 2 years with scheduled adverse event assessments. The prespecified primary outcome was ischemic stroke, systemic embolism or cardiovascular (CV) death at 2 years. We also compared the rate of procedural success, device-related thrombus (DRT) and major bleeding between genders.

Results

702 men and 386 women underwent LAAO. Implant successwas high, and similar between men and women (98.9 vs 99.5%, p = 0.58). Similarly, no difference was observed in the primary outcome (12.0 vs 12.5%, p = 0.82). Compared to the CHA₂DS₂-VASc predicted rate, we observed a numerically greater absolute risk reduction of ischemic stroke in women (from 7.6 to 2.1%/year) than men (from 6.2 to 2.2%/year). DRT through 2 years was similar between groups (1.6%, p = 0.96). We found no significant gender difference in terms of periprocedural or long-term (7.1 vs 7.6%/year) major bleeding.

Conclusions

In this large group of patients undergoing LAAO using the Amplatzer™ Amulet™ device we found no significant gender difference in terms of procedural or long-term clinical outcomes. Similarly to oral anticoagulation, device-based LAA occlusion renders AF-related stroke risk similar in women and men.

Clinical trial registration

Clinicaltrials.gov Identifier: NCT02447081.

https://clinicaltrials.gov/ct2/show/NCT02447081.

Sex matters in stroke: A review of recent evidence on the differences between women and men

For the most part, stroke is a disease of old age. With the predicted increase in the aged population and longer life expectancies, the number and proportion of people living with stroke is expected to increase, especially among women and the elderly. For those who suffer stroke, there is a high likelihood of experiencing death and severe disability. Therefore, the issue of stroke amongst women (and men) is a key priority in global public health. In this review, we consider sex and gender differences in ischemic and hemorrhagic stroke, and we summarize data that outlines the epidemiology, risk factor, treatment recovery and prevention of stroke. We discuss possible mechanisms for the sex differences, specifically in areas of biology, medical management and social and behavioral context. With evidence showing that women and men experience stroke differently, sex must be taken into account when treating patients and when designing clinical trials.

Female Sex as a Thromboembolic Risk Factor in the Era of Nonvitamin K Antagonist Oral Anticoagulants

Sex-specific differences have been definitively demonstrated in cardiovascular (CV) diseases. These differences can also impact on the effects of CV therapies. Female sex is recognized as an independent predictor of thromboembolic risk, particularly in older patients. Most of strokes are due to atrial fibrillation (AF). Women affected by AF have higher stroke risk compared to men. The introduction of novel oral anticoagulants (NOACs) for long-term anticoagulation completely changed the anticoagulant therapeutic approach and follow-up of patients affected by nonvalvular atrial fibrillation (NVAF). CHA2DS2-VASc stroke risk scoring in use in the current international guidelines attributes 1 point to “female sex”. Besides, no anticoagulation is indicated for AF female patients without other risk factors. Interestingly, NOACs seem to normalize the differences between males and females both in terms of safety and efficacy, whereas residual higher stroke risk and systemic embolism persist in AF women treated with vitamin K antagonist anticoagulants VKA with optimal time in therapeutic range. Based on the CHA2DS2-VASc score, NOACs represent the preferred choice in NVAF patients. Moreover, complete evaluation of apparently lower risk factor along with concomitant clinical conditions in AF patients appears mandatory, particularly for female patients, in order to achieve the most appropriate anticoagulant treatment, either in male or in female patients. The present review was performed to review sex differences in AF-related thromboembolic risk reported in the literature and possibly highlight current knowledge gaps in prevention and management that need further research.

Clinical outcomes of cerebral infarction in nonagenarians compared among four age groups

BACKGROUND

Average female life expectancy in Japan is approximately 90 years. Occasionally, we encounter stroke patients older than 90 years.

AIMS

To determine the clinical features and outcomes associated with cerebral infarction in patients aged ≥ 90 years.

METHODS

We examined 289 consecutive patients (163 males, 129 females; mean age 77.5 years) diagnosed with cerebral infarction. We divided them into four groups according to age in years: middle (< 65), pre-old (65-74), old (75-89), and super old (≥ 90). We divided the super old group into mild symptoms (NIHSS ≤ 5) and severe symptoms (NIHSS > 5) and examined outcomes.

RESULTS

Statistically significant associations were observed between female sex, cardiogenic infarction, and high complication rates and super old age. NIHSS and mRS scores at 30-day post-stroke were higher in the super old group. In some cases, complications led to poor prognoses. Eighty-seven percent of patients with mild symptoms (NIHSS ≤ 5) recovered to mRS 0-2 similar to the younger age group. None of the patients with severe symptoms (NIHSS > 5) recovered to mRS 0-2.

DISCUSSION

We investigated the clinical outcomes following cerebral infarction in patients aged 90 years or older and found that mild symptoms were consistently associated with good prognoses, regardless of patients' age.

CONCLUSIONS

Patients in the super old group had more severe symptoms and poorer outcomes than younger age groups. However, patients with mild symptoms tended to have better prognoses and returned to daily life similar to the younger age group.

Sex-related differences in prevalence, treatment and outcomes in patients with atrial fibrillation

To analyze sex-related differences about AF prevalence, use of OAC and outcomes focusing on the older age classes. We used administrative data of the Lombardy Region, describing period prevalence, use of OAC and outcomes from 2002 to 2014 for all patients diagnosed with AF. AF prevalence over the 2002-2014 period was higher in males than in females (2.7% vs. 2.1%, p < 0.001), increasing with age. From 2003 to 2014, not treated AF patients decreased mostly in males (from 40.3 to 33.7% with respect to 43.7-39.8% in females). Age-stratified adjusted logistic regression analysis found that females were more likely treated with OAC when < 65 years in 2003 (OR 1.51, 95% CI 1.35-1.69) and in 2014 (OR 1.32, 95% CI 1.13-1.53); contrariwise, were less likely treated with OAC when age ≥ 75 years, in 2003 (OR 0.92, 95% CI 0.86-0.98) and in 2014 (OR 0.77, 95% CI 0.72-0.81).Adjusted Cox regression analysis confirmed that female AF patients had a higher risk of stroke (HR 1.18, 95% CI 1.14-1.21) and a lower risk of major bleeding (HR 0.83, 95% CI 0.80-0.86), while, had a lower risk for all-cause death (HR 0.82, 95% CI 0.80-0.83). AF prevalence was higher in male than in female patients, while thromboembolic risk was higher in female. Older female patients were under-treated with OAC particularly in recent years. Over long-term follow-up, female had a higher risk of stroke and a lower risk of major bleeding and all-cause death.

Sex differences in stroke

Sex disparities within the field of stroke, including subarachnoid hemorrhages (SAHs), have been in focus during the last 2 decades. It is clear that stroke incidence is higher in men, and also that men have their first stroke earlier than women. On the other hand, women have more severe strokes, mainly because cardioembolic strokes are more common in women. This leads to higher case fatality and worse functional outcome in women. It has often been pointed out that women more often have nontraditional stroke symptoms, and therefore may seek medical help later. After discharge from the hospital, female stroke survivors live alone in many cases and are dependent on external care. Therefore, these women frequently rate their quality of life (QoL) lower than men do. Female spouses more often provide help to their male stroke survivors than the reverse, and they accept a heavier burden. These caregivers are at high risk for depression, low QoL, and low psychologic wellbeing. SAH is a special form of stroke, often caused by a ruptured aneurysm. It is about 20% more common in women. The case fatality is high, but does not differ between the sexes.

Women Who Have Ischemic Strokes Have a Higher Burden of Left Atrial Fibrosis Than Men

Background and Purpose- Women with atrial fibrillation (AF) have a higher risk of stroke than men who have AF. Atrial fibrosis is a marker of atrial disease that precedes the appearance of AF increasing the risk of ischemic stroke. We aimed to determine whether female sex is independently associated with left atrial fibrosis in stroke patients. Methods- We prospectively included a consecutive sample of ischemic stroke patients aged over 50 years of age. Late gadolinium enhancement cardiac magnetic resonance imaging was performed to quantify the severity of left atrial fibrosis and the wall pattern of its distribution. A multivariable linear regression analysis was performed to determine whether female sex was independently associated with left atrial fibrosis after adjusting for potential confounders namely AF and age. Results- One hundred twenty-four patients were deemed eligible; 117 patients were included (7 were excluded because of cardiomyopathy identified by cardiac magnetic resonance imaging). All had usable cardiac magnetic resonance imaging data. Fifty-three patients (45.3%) were women. Women were older and were less frequently treated with angiotensin-converting-enzyme inhibitors. Ninety-one patients had any degree of atrial fibrosis. Women had a higher percentage of atrial fibrosis than men-median (interquartile range)-18% (17) versus 10% (20). In a multivariable linear regression model adjusted for demographics, medications, AF, comorbidities, and cardiac parameters, female sex was found to be independently associated with left atrial fibrosis. Women were found to have more 4.70% of left atrial fibrosis than men (95% CI, 0.70-8.71%; P=0.02) after controlling for confounders. Conclusions- Female sex was found to be independently associated with left atrial fibrosis after controlling for confounders such as AF and age. Further studies are needed to understand if this contributes to the increased stroke risk related to AF in women compared with men.

Epicardial Adipose Tissue and Cardiovascular Disease

PURPOSE OF REVIEW

Epicardial adipose tissue has been associated with the development/progression of cardiovascular disease. We appraise the strength of the association between epicardial adipose tissue and development/progression of cardiovascular diseases like coronary artery disease, atrial fibrillation, and heart failure with preserved ejection fraction.

RECENT FINDINGS

Cross-sectional clinical and translational correlative studies have established an association between epicardial adipose tissue and progression of coronary artery disease. Recent studies question this association and underline the need for longitudinal studies. Epicardial adipose tissue also plays a definite role in the pathobiology of atrial fibrillation and its recurrence after ablation. In contrast to an early paradigm, epicardial adipose tissue does not appear to play a key role in the pathogenesis of heart failure with preserved ejection fraction in obese patients. The association of epicardial adipose tissue with atrial fibrillation is robust. In contrast, the association of epicardial adipose tissue with coronary artery disease and heart failure with preserved ejection fraction is tenuous. Additional research, including longitudinal studies, is needed to confirm or refute these proposed associations.

Stroke risk stratification in atrial fibrillation: a review of common risk factors

Atrial Fibrillation (AF) has become a major global health concern being the most common sustained arrhythmia in clinical practice. Risk factors for AF include congestive heart failure, hypertension, increasing age and diabetes. Many of these factors also increase the risk for thromboembolism and ischemic stroke in AF patients. Great efforts have been made from the latter part of the 20th century towards developing an ideal stroke risk stratification tool in AF with the aim of reducing the incidence of stroke in AF patients and the limiting unnecessary use of thromboprophylaxis. The thromboembolic risks posed by AF with valvular heart disease are an important subgroup that contributes to a significant proportion of stroke in AF patients globally. We review the evolution of stroke risk stratification and summarize the guidelines for stroke prevention in non-valvular AF as well as AF with valvular heart disease, and the most recent recommendations on stroke prevention in AF patients. Abbreviations: AF: Atrial Fibrillation; ACS: Acute Coronary Syndrome; CAD: Coronary Artery Disease; CCF: Congestive Cardiac Failure; DM: Diabetes Mellitus; EHRA: Evaluated Heartvalves, Rheumatic or Artificial; ICH: Intracranial Hemorrhage; NOACs: Novel Oral Anticoagulants; OAC: Oral Anticoagulants; PAD: Peripheral Arterial Disease ; TIA: Transient Ischemic Attack; VHD: Valvular Heart Disease.

Gender Differences in Antithrombotic Treatment for Newly Diagnosed Atrial Fibrillation: The GLORIA-AF Registry Program

AIMS

Data on gender differences in oral anticoagulation for stroke prevention in patients with atrial fibrillation are conflicting, largely limited to regional reports and vitamin K antagonist use. We aimed to analyze gender-specific anticoagulant prescription patterns early following the introduction of non-vitamin K antagonist oral anticoagulants (NOACs) in a large, global registry on atrial fibrillation.

METHODS

The Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF) is an international registry program involving patients with newly diagnosed atrial fibrillation (<3 months from arrhythmia onset). We used data from 15,092 consecutive patients (median age, 71.0 years; 45.5% were women) enrolled between 2011 and 2014. Globally, 79.7% of women and 80.2% of men were anticoagulated; the absolute between-gender difference in prevalence of anticoagulant use was -0.5% (95% confidence interval, -1.8% to 0.8%). Vitamin K antagonists were prescribed to 32.8% and 31.9% (NOACs 46.8% and 48.3%) of women and men, respectively.

RESULTS

No confounder for the association between gender and anticoagulant prescription was identified. Between-gender differences in anticoagulant use (lower use in women compared with men by decreasing order of magnitude of the difference) were found for CHA₂DS₂-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke/transient ischemic attack, vascular disease, age 65-74 years, sex category [female]) score = 1; CHADS₂ (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke) score = 0; previous bleeding; age <65 years; no history of hypertension; myocardial infarction; coronary artery disease; North America region; and specialist office setting.

CONCLUSION

Globally, the prevalence of anticoagulant use is similar in women and men. The decision to prescribe oral anticoagulation seems to depend predominantly on guideline-related differences in stroke risk stratification rather than on gender.

Sex differences in stroke and major adverse clinical events in patients with atrial fibrillation: A systematic review and meta-analysis of 993,600 patients

BACKGROUND

Atrial fibrillation (AF) is the most commonly diagnosed arrhythmia, which is associated with an increased risk of stroke. Several studies have suggested that female AF patients could have a greater risk for stroke and thromboembolic events (TE).

METHODS

A systematic literature review update and meta-analysis was conducted using Pubmed. The search used the terms "atrial fibrillation", "gender", "sex", "female", "women", "stroke", "thromboembolism". Main aim of the study was to compare and male AF patients for occurrence of stroke and TE. Secondary outcomes were: major bleeding, cardiovascular (CV) death and all-cause death.

RESULTS

Forty-four studies were included in the analysis including 993,603 patients (48.9% women). After pooling the data, there was a higher risk of stroke for women vs. male AF patients (hazard ratio [HR]: 1.24; 95% confidence intervals [CIs]: 1.14-1.36). Overall, TE risk was not different between female and male patients, despite sensitivity analysis left some uncertainties. No sex differences were found for major bleeding, CV death and all-cause death. A significant relationship between increasing age and the difference in stroke risk between female and male AF patients was found (Delta HR: 1.01; 95% CI: 1.00-1.03 for each year of age increase).

CONCLUSIONS

Female patients with AF are at increased risk of stroke compared to men. A significant relationship between increasing age and stroke risk in women compared to men was found, most evident at age > 65 years. Female sex may act as a stroke risk modifier, particularly in elderly and very elderly AF subjects, conferring a significant increase in stroke risk.

Pharmacological thrombolysis for acute ischemic stroke treatment: Gender differences in clinical risk factors

BACKGROUND

In a stroke population, women have a worse outcome than men when untreated. In contrast, there is no significant difference in treated patients. In this study, we determined whether clinical variables represent a promising approach to assist in the evaluation of gender differences in a stroke population.

METHODS

We analyzed data from ischemic stroke patients' ≥18 years-old from the stroke registry on rtPA administration and identified gender differences in clinical factors within inclusion and exclusion criteria in a stroke population that received rtPA. Multivariate analysis was used to adjust for patient demographic and clinical variables.

RESULTS

Of the 241 eligible stroke patients' thrombolytic therapy, 49.4% were females and 50.6% were males. Of the 422 patients that did not receive rtPA, more women (235) were excluded from rtPA than men (187) (P<0.05). In the male population, exclusion from rtPA was associated with history of a previous stroke (P<0.05, OR=2.028), hypertension (P<0.05, OR=0.519), and NIH stroke score (P<0.0001, OR=0.893). In female stroke patients, exclusion from rtPA was associated with previous history of stroke (P<0.05, OR=2.332), diabetes (P<0.05, OR=1.88) and NIH stroke score (P<0.05, OR=0.916).

CONCLUSIONS

Despite similarities in different areas of stroke care for both men and women, more women with diabetes, previous history of stroke and higher NIH scores are more likely to be excluded from thrombolytic therapy. Men with a previous history of stroke, hypertension and higher NIH scores are more likely to be excluded rtPA even after adjustment for confounding variables.

Atrial Fibrillation and Cause-Specific Risks of Pulmonary Embolism and Ischemic Stroke

Background

Atrial fibrillation (AF) is a well‐established risk factor for ischemic stroke (IS). Emerging evidence also indicates an association between AF and pulmonary embolism (PE). Because IS may potentially mediate the observed risk of PE in AF, we aimed to assess the impact of AF on the cause‐specific risks of PE and IS in a large cohort recruited from the general population.

Methods and Results

We observed 29 842 participants from 3 surveys of the Tromsø study (inclusion in 1994–1995, 2001–2002, and 2007–2008) to the end of 2012. Incident events of AF, IS, and PE during follow‐up were recorded, and information on potential confounders was obtained at baseline. Cox regression models, with AF as a time‐dependent variable, were used to calculate cause‐specific hazard ratios (HRs) with 95% confidence intervals (CIs) for PE and IS. There were 2067 participants diagnosed as having AF, 296 with PE and 1164 with IS, during a median of 17.6 years of follow‐up. The risks of PE (HR, 10.88; 95% CI, 6.23–18.89) and IS (HR, 6.16; 95% CI, 4.47–8.48) were substantially increased during the first 6 months after AF diagnosis, with crude incidence rates of 18.5 per 1000 person‐years for PE and 52.8 per 1000 person‐years for IS. The risk estimates remained elevated for both PE (HR, 1.72; 95% CI, 1.10–2.71) and IS (HR, 2.45; 95% CI, 2.05–2.92) throughout the study period.

Conclusions

AF was associated with increased cause‐specific risks of both PE and IS. Our findings infer that the risk of PE in AF is not explained by intermediate IS.

Gender and AF: Differences and Disparities

AF is the most common clinical arrhythmia encountered. A wealth of evidence has improved our ability to diagnose and effectively treat AF. An intriguing aspect of this common disease – gender-based differences – is well recognized, but poorly understood. In this brief review, we will explore the accumulating evidence suggesting a gender-based disparity in the prevalence, pathogenesis and management of AF.

Gender Differences in the Trends of Hospitalizations for Acute Stroke Among Patients With Atrial Fibrillation in the United States: 2005 to 2014

Female gender was included in stroke prediction algorithms in an attempt to improve anticoagulation rates in women with atrial fibrillation (AF). It is unclear if these efforts reduced stroke burden in women with AF. To bridge this literature gap, using the Nationwide Inpatient Sample, we assessed gender differences in the trends of hospitalizations for stroke among patients with AF in the United States in 2005 to 2014. International classification of diseases, 9th revision, clinical modification codes were used to abstract AF and stroke diagnoses. From 2005 to 2014, 18,413,291 hospitalizations of women with AF and 18,035,866 hospitalizations of men with AF were reported. Of these, 740,635 hospitalizations in women and 595,730 hospitalizations in men had stroke as the primary diagnosis. Age-adjusted stroke hospitalizations increased in women (443 per million in 2005 to 495 per million in 2014) as well as in men (351 per million in 2005 to 453 per million in 2014) (p trend < 0.001). Further, anticoagulation rates increased in women (11.5% in 2005 to 24.0% in 2014) as well as in men (11.7% in 2005 to 24.9% in 2014). Stroke hospitalizations involving anticoagulated patients with AF decreased in women (411 per million in 2005 to 347 per million in 2014) as well as in men (402 per million in 2005 to 311 per million in 2014) (p trend < 0.001). In conclusion, although we noted an increasing trend of stroke hospitalizations in both genders, it is reassuring to note that stroke hospitalizations involving anticoagulated patients with AF is decreasing in both genders and in particular among women.

Trends in the rates of hospitalizations for acute stroke among patients over 90 years of age with atrial fibrillation in the United States: from 2005 to 2014

BACKGROUND

Acute stroke (AS) rates in patients over 90 years of age (very elderly) with atrial fibrillation (AF) in the United States (US) are not known. We assessed trends in hospitalizations for AS among very elderly with AF in the US from 2005 to 2014.

METHODS

We used the nationwide inpatient sample (NIS) from the USA; 2005-2014. AF and AS diagnoses were abstracted using international classification of diseases, 9th Revision, clinical modification (ICD-9-CM) codes.

RESULTS

From 2005 to 2014, 3,606,073 hospitalizations of very elderly with AF were reported. Of these, 188,948 hospitalizations (141,822 hospitalizations in women and 47,126 hospitalizations in men) had AS as the primary diagnosis. Age adjusted AS hospitalizations increased in the total cohort (3217/million in 2005 to 3871/million in 2014), in women (3540/million in 2005 to 4487/million in 2014) and in men (2490/million in 2005 to 3173/million in 2014) (P < 0.001). Anticoagulation rates increased in women (8% in 2005 to 19.9% in 2014) and in men (8.9% in 2005 to 21.6% in 2014). AS rates, though numerically lower than the total cohort, showed an increasing trend in anticoagulated patients as well (all anticoagulated patients: 212/million in 2005 to 513/million in 2014; anticoagulated women: 224/million in 2005 to 529/million in 2014, anticoagulated men: 184/million in 2005 to 518/million in 2014).

CONCLUSIONS

There is an increasing trend in AS hospitalizations among nonagenarians with AF in the US despite improving utilization of anticoagulants in this patient population. The etiologies driving this alarming trend are unclear and require further study.

Influence of Sex on the Association Between Epicardial Adipose Tissue and Left Atrial Transport Function in Patients With Atrial Fibrillation: A Multislice Computed Tomography Study

BACKGROUND

Epicardial adipose tissue (EAT) is known to play an important role in atrial fibrillation substrate remodeling; however, the influence of sex on the association between EAT and left atrial (LA) transport function has not been elucidated.

METHODS AND RESULTS

Of the 514 patients who underwent an index atrial fibrillation ablation procedure, 123 postmenopausal women with no history of hormone replacement therapy and 123 men who were matched for age, body mass index, type of atrial fibrillation, and CHADS₂ score were enrolled. Before the procedure, LA volume, LA emptying fraction, and EAT volume were assessed using multislice computed tomography. Blood samples were obtained from a coronary sinus for analysis of serum adiponectin level before the ablation procedure. There were no differences in baseline demographics and laboratory findings between sexes. Compared with men, women had significantly less total EAT (P<0.001) and higher serum adiponectin levels (P=0.022) but higher proportions of periatrial EAT to total EAT volume (P/T EAT ratio, P<0.001), lower LA emptying fraction (P=0.042), and lower LA voltage (P=0.034). The ratio of periatrial to total EAT volume correlated significantly with LA emptying fraction and LA voltage in both sexes, whereas total EAT volume and serum adiponectin level did not. On multivariate analysis, increased LA volume and higher periatrial:total EAT volume ratio were independent predictors of decreased LA emptying fraction in both sexes.

CONCLUSIONS

Compared with matched men, postmenopausal women with atrial fibrillation had higher periatrial adiposity, which was independently correlated with decreased LA voltage and LA transport function.

Atrial Fibrillation and Ventricular Arrhythmias: Sex Differences in Electrophysiology, Epidemiology, Clinical Presentation, and Clinical Outcomes

Sex-specific differences in the epidemiology, pathophysiology, clinical presentation, clinical treatment, and clinical outcomes of atrial fibrillation (AF), sustained ventricular arrhythmias, and sudden cardiac death are recognized. Sex hormones cause differences in cardiac electrophysiological parameters between men and women that may affect the risk for arrhythmias. The incidence and prevalence of AF is lower in women than in men. However, because women live longer and AF prevalence increases with age, the absolute number of women with AF exceeds that of men. Women with AF are more symptomatic, present with more atypical symptoms, and report worse quality of life in comparison with men. Female sex is an independent risk factor for death or stroke attributable to AF. Oral anticoagulation therapy for stroke prevention has similar efficacy for men and women, but older women treated with warfarin have a higher residual risk of stroke in comparison with men. Women with AF are less likely to receive rhythm control antiarrhythmic drug therapy, electric cardioversion, or catheter ablation in comparison with men. The incidence and prevalence of sustained ventricular arrhythmias and sudden cardiac death are lower in women than in men. Women receiving implantable cardioverter defibrillators for primary prevention of sudden cardiac death are less likely to experience sustained ventricular arrhythmias in comparison with men. In contrast, women receiving a cardiac resynchronization therapy implantable cardioverter defibrillator for the treatment of heart failure are more likely to benefit than men. Women are less likely to be referred for implantable cardioverter defibrillator therapy despite current guideline recommendations. Women are more likely to experience a significant complication related to implantable cardioverter defibrillator implantation in comparison with men. Whether sex differences in treatment decisions reflect patient preferences or treatment biases requires further study.

Impact of gender on event rates at 1 year in patients with newly diagnosed non-valvular atrial fibrillation: contemporary perspective from the GARFIELD-AF registry

OBJECTIVES

Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) explored the impact of gender, risk factors and anticoagulant (AC) treatment on 1-year outcomes in patients with non-valvular atrial fibrillation (NVAF).

DESIGN

GARFIELD-AF is a prospective non-interventional registry.

SETTING

Investigator sites (n=1048) are representative of the care settings/locations in each of the 35 countries.

PARTICIPANTS

Patients ≥18yrs with newly diagnosed (≤6 weeks' duration) NVAF and ≥1 investigator-determined stroke risk factors.

MAIN OUTCOME MEASURES

Event rates per 100 person-years were estimated from the Poisson model and HRs and 95% CIs calculated.

RESULTS

Of 28 624 patients (women 44.4%; men 55.6%) enrolled, there were more elderly (≥75 years) women (46.9%) than men (30.4%). All-cause mortality rates per 100 person-years (95% CI) for women and men were 4.48 (4.12 to 4.87) and 4.04 (3.74 to 4.38), respectively, stroke/systemic embolism (SE) (1.62 (1.41 to 1.87) and 1.17 (1.01 to 1.36)) and major bleeding (0.93 (0.78 to 1.13) and 0.79 (0.66 to 0.95)). After adjustment for baseline risk factors in treated and untreated patients, HRs (95% CI) for women (relative to men) for stroke/SE rates were 1.3-fold higher in women (HR 1.30 (1.04 to 1.63)), and similar for major bleeding (1.13 (0.85 to 1.50)) and all-cause mortality (1.05 (0.92 to 1.19)). Antithrombotic treatment patterns in men and women were almost identical. 63.8% women and 62.9% men received AC± antiplatelets. Relative to no AC treatment, the reduction in stroke/SE rates with AC treatment was greater (p=0.01) in men (HR 0.45 (0.33 to 0.61)) than women 0.77 (0.57 to 1.03). All-cause mortality reduction with AC treatment was similar (women: 0.65 (0.54 to 0.77); men: 0.57 (0.48 to 0.68)). The risk of major bleeding when treated with AC versus no AC was 2.33 (1.41 to 3.84) in men and 1.86 (1.16 to 2.99) in women (p value=0.53).

CONCLUSIONS

Women have a higher risk of stroke/SE and the reduction in stroke/SE events rates with AC treatment is less in women than in men.

TRIAL REGISTRATION NUMBER

NCT01090362.

Sex-related differences in risk factors, type of treatment received and outcomes in patients with atrial fibrillation and acute stroke: Results from the RAF-study (Early Recurrence and Cerebral Bleeding in Patients with Acute Ischemic Stroke and Atrial Fibrillation)

Introduction

Atrial fibrillation is an independent risk factor of thromboembolism. Women with atrial fibrillation are at a higher overall risk for stroke compared to men with atrial fibrillation. The aim of this study was to evaluate for sex differences in patients with acute stroke and atrial fibrillation, regarding risk factors, treatments received and outcomes.

Methods

Data were analyzed from the “Recurrence and Cerebral Bleeding in Patients with Acute Ischemic Stroke and Atrial Fibrillation” (RAF-study), a prospective, multicenter, international study including only patients with acute stroke and atrial fibrillation. Patients were followed up for 90 days. Disability was measured by the modified Rankin Scale (0–2 favorable outcome, 3–6 unfavorable outcome).

Results

Of the 1029 patients enrolled, 561 were women (54.5%) (p < 0.001) and younger (p < 0.001) compared to men. In patients with known atrial fibrillation, women were less likely to receive oral anticoagulants before index stroke (p = 0.026) and were less likely to receive anticoagulants after stroke (71.3% versus 78.4%, p = 0.01). There was no observed sex difference regarding the time of starting anticoagulant therapy between the two groups (6.4 ± 11.7 days for men versus 6.5 ± 12.4 days for women, p = 0.902). Men presented with more severe strokes at onset (mean NIHSS 9.2 ± 6.9 versus 8.1 ± 7.5, p < 0.001). Within 90 days, 46 (8.2%) recurrent ischemic events (stroke/TIA/systemic embolism) and 19 (3.4%) symptomatic cerebral bleedings were found in women compared to 30 (6.4%) and 18 (3.8%) in men (p = 0.28 and p = 0.74). At 90 days, 57.7% of women were disabled or deceased, compared to 41.1% of the men (p < 0.001). Multivariate analysis did not confirm this significance.

Conclusions

Women with atrial fibrillation were less likely to receive oral anticoagulants prior to and after stroke compared to men with atrial fibrillation, and when stroke occurred, regardless of the fact that in our study women were younger and with less severe stroke, outcomes did not differ between the sexes.

Decision-Making in Clinical Practice: Oral Anticoagulant Therapy in Patients with Non-valvular Atrial Fibrillation and a Single Additional Stroke Risk Factor

Approximately 1 in 3-4 patients presenting with an ischemic stroke will also have atrial fibrillation (AF), and AF-related strokes can be effectively prevented using oral anticoagulant therapy (OAC), either with well-controlled vitamin K antagonists (VKAs) or non-vitamin K antagonist oral anticoagulants (NOACs). In addition, OAC use (both VKAs and NOACs) is associated with a 26% reduction in all-cause mortality (VKAs) or an additional 10% mortality reduction with NOACs relative to VKAs. The decision to use OAC in individual AF patient is based on the estimated balance of the benefit from ischemic stroke reduction against the risk of major OAC-related bleeding [essentially intracranial hemorrhage (ICH)]. Better appreciation of the importance of VKAs' anticoagulation quality [a target time in therapeutic range (TTR) of ≥70%] and the availability of NOACs (which offer better safety compared to VKAs) have decreased the estimated threshold for OAC treatment in AF patients towards lower stroke risk levels. Still, contemporary registry-based data show that OAC is often underused in AF patients at increased risk of stroke. The uncertainty whether to use OAC may be particularly pronounced in AF patients with a single additional stroke risk factor, who are often (mis)perceived as having a "borderline" or insufficient stroke risk to trigger the use of OAC. However, observational data from real-world AF cohorts show that the annual stroke rates in such patients are higher than in patients with no additional stroke risk factors, and OAC use has been associated with reduction in stroke, systemic embolism, or death in comparison to no therapy or aspirin, with no increase in the risk of bleeding relative to aspirin. In this review article, we summarize the basic principles of stroke risk stratification in AF patients and discuss contemporary real-world evidence on OAC use and outcomes of OAC treatment in AF patients with a single additional stroke risk factor in various real-world AF cohorts.