Associations of anemia with stroke, bleeding, and mortality in atrial fibrillation: A systematic review and meta-analysis

Effects of Longitudinal Changes in Anemia Status on Clinical Outcomes in Patients With Non-Valvular Atrial Fibrillation - Analysis From the Hokuriku-Plus AF Registry

BACKGROUND

Anemia, a common comorbidity in older patients with heart failure (HF) and atrial fibrillation (AF), is associated with an increased risk of adverse events. This study evaluated the prognostic effects of longitudinal changes in anemia status on clinical outcomes in patients with AF.

METHODS AND RESULTS

We prospectively evaluated data of 1,388 patients with AF from the Hokuriku-Plus AF Registry (1,010 men; mean [±SD] age 72.3±9.7 years) and recorded the incidence of death, HF, thromboembolism, and major bleeding. Of these patients, the 1,233 for whom hemoglobin levels were available at baseline and at the 1-year follow-up were further evaluated. Patients were categorized into 3 groups based on longitudinal changes in 1-year anemia status: Group 1, AF without anemia; Group 2, AF with improved anemia; and Group 3, AF with sustained or new-onset anemia. Over the 1-5 years of follow up, the incidences of death, HF, thromboembolism, and major bleeding were significantly higher among patients with than without anemia. In addition, the incidence of death or HF was significantly higher in Group 3 than in Groups 1 and 2. Multivariate analysis revealed no anemia or improvement in anemia in 1 year as an independent predictor for a favorable prognosis for cardiovascular death and HF.

CONCLUSIONS

Recovery from anemia may be associated with a favorable clinical course of AF.

Traumatic bleeding and mortality in mice are intensified by iron deficiency anemia and can be rescued with tranexamic acid

Background

Clinical evidence suggests that anemia exacerbates traumatic bleeding and worsens outcomes.

Objectives

To study the influence of iron deficiency anemia on traumatic bleeding, coagulopathy, and mortality.

Methods

C57BL/6J mice received an iron-deficient diet (8 weeks; ±1 mg intraperitoneal iron dextran 2 weeks before trauma). Control mice received a normal diet. Iron deficiency anemia was confirmed by hematocrit, red cell indices, and liver iron. Mice received saline or tranexamic acid (TXA; 10 mg/kg) just before liver laceration. Blood loss, coagulopathy (activated partial thromboplastin time, factor [F]II, FV, FVIII, FX, and fibrinogen), D-dimer, thrombin-antithrombin complexes, and plasmin-alpha-2-antiplasmin complexes were analyzed at 15 and 60 minutes, and a cytokine panel was performed at 60 minutes and 6 hours after trauma. Survival was monitored for 7 days.

Results

Compared with nonanemic mice, anemic mice had lower hematocrit and hepatic iron content. Anemic mice experienced higher blood loss compared with nonanemic mice, which was reduced by TXA. Both groups developed traumatic coagulopathy characterized by activated partial thromboplastin time prolongation, thrombin-antithrombin complex formation, and depletion of FV, FVIII, and fibrinogen. TXA corrected the coagulopathy. However, plasmin-alpha-2-antiplasmin complex formation and D-dimers, markers of fibrinolysis, were higher in anemic mice and were not corrected by TXA. Seven-day survival was low in anemic mice, and rescued by TXA, but high in nonanemic mice without additional improvement by TXA. Among cytokines, only interleukin-6 increased, which was prevented by TXA most notably in anemic mice.

Conclusion

These observations provide first and critical proof-of-principle evidence that anemia accelerates traumatic bleeding and increases mortality, which could be rescued by anemia correction (parenteral iron) or periprocedural TXA.

Prognosis of anemic patients with atrial fibrillation undergoing percutaneous coronary intervention

BACKGROUND

There are limited data regarding whether anemia is associated with adverse clinical outcomes in patients with atrial fibrillation (AF) after percutaneous coronary intervention (PCI).

METHODS

Patients with AF undergoing PCI at 15 institutions between January 2015 and March 2021 were included in this analysis. Based on the baseline hemoglobin levels, moderate to severe anemia was defined as hemoglobin levels <11 g/dL, and mild anemia was defined as hemoglobin levels 11-12.9 g/dL for men and 11-11.9 g/dL for women. Clinical outcomes within 1 year, including major adverse cardiovascular events (MACE: all-cause death, myocardial infarction, stent thrombosis, and stroke) and major bleeding events (BARC 3 or 5), were compared among patients with moderate/severe anemia, mild anemia, and no anemia.

RESULTS

In a total of 746 enrolled patients, 119 (16.0%) and 168 (22.5%) patients presented with moderate/severe and mild anemia. The incidence of MACE (22.5%, 11.0%, and 9.1%, log-rank p < 0.001), all-cause death (20.0%, 7.2%, and 4.8%, log-rank p < 0.001), and major bleeding events (10.7%, 6.5%, and 2.7%, log-rank p < 0.001) were the highest in the moderate/severe anemia group compared with the mild and no anemia groups. Multivariable Cox regression analyses determined moderate/severe anemia as an independent predictor for MACE (p = 0.008), all-cause death (p = 0.005), and major bleeding events (p = 0.031) at 1 year after PCI.

CONCLUSION

Moderate/severe anemia was significantly associated with the higher incidence of MACE and all-cause death as well as major bleeding events compared with mild and no anemia in AF patients undergoing PCI.

Renin-angiotensin-aldosterone system inhibitors and mortality risk in elderly patients with atrial fibrillation. Insights from the nationwide START registry

BACKGROUND

Arterial hypertension is the most common cardiovascular comorbidity in atrial fibrillation (AF). Few studies investigated management strategies of hypertension in AF.

MATERIALS AND METHODS

We included 5769 AF patients on oral anticoagulants from the nationwide ongoing Italian START registry. We investigated the prescription of antihypertensive drugs and mortality risk. Subgroup analyses according to sex and major cardiovascular comorbidities were performed.

RESULTS

Mean age was 80.8 years, 46.1% were women; 80.3% of patients were hypertensive. Furosemide (30.1%) was the most frequent diuretic followed by hydrochlorothiazide (15.4%) and potassium canrenoate (7.9%). 61.1% received β-blockers: 34.2% bisoprolol, 6.2% atenolol. Additionally, 36.9% were on angiotensin converting enzyme inhibitors (ACE-I): ramipril (20.9%), enalapril (5.3%) and perindopril (2.8%); 31.7% were on angiotensin receptors blockers (ARBs): valsartan (7.6%) and irbesartan (6.4%). Amlodipine and lercanidipine were prescribed in 14.0% and 2.3%, respectively. ACE-I (p < 0.001), α-blockers (p = 0.020) and Dihydropyridines calcium channel blockers (p = 0.004) were more common in men, while ARBs (p = 0.008), thiazide diuretics (p < 0.001) and β-blockers (p < 0.001) in women. During 22.61 ± 17.1 months, 512 patients died. Multivariable Cox regression analysis showed that ACE-I (Hazard ratio [HR] 0.758, 95% Confidence Interval [95%CI] 0.612-0.940, p = 0.012) and ARBs (HR 0.623, 95%CI 0.487-0.796, p < 0.001) inversely associated with mortality. ACE-I/ARBs inversely associated with mortality in both sexes and in patients with diabetes. This associastion was evident for ACE-I in patients with previous cardiovascular disease, and for ARBs in HF.

CONCLUSION

A lower mortality risk was found in AF patients on ACE-I/ARBs. Different prescription patterns of antihypertensive drugs between men and women do exist.

Including hemoglobin levels and female sex provide the additional predictive value of the APPLE score for atrial fibrillation recurrence post-catheter ablation

OBJECTIVE

We probed whether the addition of hemoglobin (HGB) or the female sex (SEX) as variables would provide additional prognostic value to the APPLE score.

METHODS

An optimized APPLE score was used to evaluate the AF recurrence risk in the consecutive populations with AF post-catheter ablation including the development (n = 562) and validation (n = 239) cohorts.

RESULTS

In the populations of AF recurrence, most patients were female sex (103/164, 62.8%), and had the lower HGB levels. After adjusting for the APPLE score, HGB level (Odds Ratio [OR], 0.828; 95% Confidence Interval [CI], 0.749-0.915; P < 0.001) and female sex (OR, 1.596; 95% CI, 1.140-2.235; P = 0.006) independently predicted AF recurrence. Adjusting the APPLE score by HGB variable improved its predictive ability for AF recurrence (C-statistic value from 0.675 to 0.711, P = 0.010), which also increased the C-indexes in the external validation (from 0.653 to 0.725, p = 0.023). The female sex variable also enhanced the C-statistic value of the APPLE score for AF recurrence at both development and external validation (C-indices from 0.675 to 0.691, P = 0.004; C-indices from 0.653 to 0.704, p = 0.037, respectively). Decision curve analysis showed that the HGB plus APPLE score was better than the SEX plus APPLE score in predicting AF recurrence in two following AF populations.

CONCLUSION

The inclusion of HGB level and female sex variables improved the predictability and clinical usefulness of adjusted APPLE score. Adjustment of the APPLE score by HGB levels may provide better predictive value than inclusion of the female sex variable.

Construction of a risk scoring system using clinical factors and RYR2 polymorphisms for bleeding complications in patients on direct oral anticoagulants

Introduction: Bleeding is one of the most undesirable complications of direct oral anticoagulants (DOACs). While the ryanodine receptor (RYR2) has been related to cardiac diseases, research on bleeding complications is lacking. This study aimed to elucidate the association between RYR2 and bleeding risk to develop the risk scoring system in patients treated with DOACs. Methods: This study was a retrospective analysis of prospectively collected samples. We selected ten SNPs within the RYR2 gene, and two models were constructed (Model I: demographic factors only, Model II: demographic and genetic factors) in multivariable analysis. Independent risk factors for bleeding were used to develop a risk scoring system. Results: A total of 447 patients were included, and 49 experienced either major bleeding or clinically relevant non-major bleeding. In Model I, patients using rivaroxaban and experiencing anemia exhibited an increased bleeding risk after adjusting for covariates. Upon incorporating genetic factors into Model I, a significant association with bleeding was also observed in cases of overdosing on DOACs and in patients with a creatinine clearance (CrCl) < 30 mL/min, in addition to rivaroxaban and anemia (Model II). Among genetic factors, RYR2 rs12594 GG, rs17682073 AA, rs3766871 GG, and rs6678625 T alleles were associated with bleeding complications. The area under the receiver operating characteristic curve (AUROC) of Model I was 0.670, whereas that of Model II increased to 0.803, demonstrating better performance with the inclusion of genetic factors. Using the significant variables in Model II, a risk scoring system was constructed. The predicted bleeding risks for scores of 0, 1-2, 3-4, 5-6, 7-8, and 9-10 points were 0%, 1.2%, 4.6%, 15.7%, 41.7%, and 73.3%, respectively. Conclusion: This study revealed an association between RYR2 and bleeding complications among patients taking DOACs and established a risk scoring system to support individualized DOAC treatment for these patients.

A review of the impact, pathophysiology, and management of atrial fibrillation in patients with heart failure with preserved ejection fraction

Patients with heart failure with preserved ejection fraction (HFpEF) and atrial fibrillation (AF) have increased mortality and increased risk of stroke. Due to the heterogeneous nature of both disease processes, it is difficult to ascertain whether the diagnosis and progression of AF is the cause of deterioration or if it is a symptom of worsening heart failure. This presents physicians with a clinical conundrum of whether optimizing their heart failure will decrease the overall AF burden or if restoration of sinus rhythm is necessary to optimize patients with HFpEF. In this paper, we will review the impact of AF in patients with HFpEF, the pathophysiology and heterogeneity of HFpEF and AF, and the management of these patients. As HFpEF and AF become more prevalent, managing these disease processes needs standardization to improve outcomes. Further research is needed to understand the complex interplay between AF and HFpEF to help determine the best management strategy.

An interpretable machine learning approach for predicting 30-day readmission after stroke

BACKGROUND

Stroke is the second leading cause of death worldwide and has a significantly high recurrence rate. We aimed to identify risk factors for stroke recurrence and develop an interpretable machine learning model to predict 30-day readmissions after stroke.

METHODS

Stroke patients deposited in electronic health records (EHRs) in Xuzhou Medical University Hospital between February 1, 2021, and November 30, 2021, were included in the study, and deceased patients were excluded. We extracted 74 features from EHRs, and the top 20 features (chi-2 value) were used to build machine learning models. 80% of the patients were used for pre-training. Subsequently, a 20% holdout dataset was used for verification. The Shapley Additive exPlanations (SHAP) method was used to explore the interpretability of the model.

RESULTS

The cohort included 6,558 patients, of whom the mean (SD) age was 65 (11) years, 3,926 were males (59.86 %), and 132 (2.01 %) were readmitted within 30 days. The area under the receiver operating characteristic curve (AUROC) for the optimized model was 0.80 (95 % CI 0.68-0.80). We used the SHAP method to identify the top 10 risk factors (i.e., severe carotid artery stenosis, weak, homocysteine, glycosylated hemoglobin, sex, lymphocyte percentage, neutrophilic granulocyte percentage, urine glucose, fresh cerebral infarction, and red blood cell count). The AUROC of a model with the 10 features was 0.80 (95 % CI 0.69-0.80) and was not significantly different from that of the model with 20 risk factors.

CONCLUSIONS

Our methods not only showed good performance in predicting 30-day readmissions after stroke but also revealed risk factors that provided valuable insights for treatments.

Association between Anemia Severity and Ischemic Stroke Incidence: A Retrospective Cohort Study

Stroke patients presenting with anemia at the time of stroke onset had a higher risk of mortality and development of other cardiovascular diseases and comorbidities. The association between the severity of anemia and the risk of developing a stroke is still uncertain. This retrospective study aimed to evaluate the association between stroke incidence and anemia severity (by WHO criteria). A total of 71,787 patients were included, of whom 16,708 (23.27%) were identified as anemic and 55,079 patients were anemia-free. Female patients (62.98%) were more likely to have anemia than males (37.02%). The likelihood of having a stroke within eight years after anemia diagnosis was calculated using Cox proportional hazard regression. Patients with moderate anemia had a significant increase in stroke risk compared to the non-anemia group in univariate analyses (hazard ratios [HR] = 2.31, 95% confidence interval [CI], 1.97-2.71, p < 0.001) and in adjusted HRs (adj-HR = 1.20, 95% CI, 1.02-1.43, p = 0.032). The data reveal that patients with severe anemia received more anemia treatment, such as blood transfusion and nutritional supplementation, and maintaining blood homeostasis may be important to preventing stroke. Anemia is an important risk factor, but other risk factors, including diabetes and hyperlipidemia, also affect stroke development. There is a heightened awareness of anemia's severity and the increasing risk of stroke development.

Iron and atrial fibrillation: A review

Atrial fibrillation (AF), one of the most common arrhythmias in clinical practice, is classified into paroxysmal, persistent, and permanent AF according to its duration. The development of AF is associated with increased cardiovascular morbidity and mortality. However, the exact etiology of this disease remains poorly understood. Recent studies found disorders of iron metabolism might be involved in the progression of AF. Abnormal iron metabolism in cardiomyocytes provides arrhythmogenic substrates through a variety of mechanisms, including calcium mishandling, ion channel remodeling, and oxidative stress overaction. Interestingly, in AF patients with iron overload, interventions on iron metabolism, such as iron chelators and ferroptosis inhibitors, has been shown to prevent AF via reducing ferroptosis. Herein, we review the possible mechanisms, consequences, and therapeutic implications of altered atrial iron handling for AF pathophysiology.

Association between Genetic Polymorphisms and Bleeding in Patients on Direct Oral Anticoagulants

Objectives: The purpose of our study is to investigate the effects of apolipoprotein B (APOB) and APOE gene polymorphisms on bleeding complications in patients receiving direct oral anticoagulants (DOACs). Methods: A total of 16 single nucleotide polymorphisms (SNPs) in 468 patients were genotyped. Six SNPs of ABCB1 (rs3842, rs1045642, rs2032582, rs1128503, rs3213619, and rs3747802), one SNP of CYP3A5 (rs776746), seven SNPs of APOB (rs1042034, rs2163204, rs693, rs679899, rs13306194, rs13306198, and rs1367117), and two SNPs of APOE (rs429358 and rs7412) were analyzed by a TaqMan genotyping assay. Multivariable logistic regression analysis with selected variables was performed for the construction of a risk scoring system. Two risk scoring systems were compared (demographic factors only vs. demographic factors and genetic factors). Results: In the multivariable analyses, two models were constructed; only demographic factors were included in Model I and both demographic factors and genetic factors in Model II. Rivaroxaban and anemia showed significant association with bleeding in both models. Additionally, ABCB1 rs3842 variant homozygote carriers (CC) and APOB rs13306198 variant allele carriers (AG, AA) had a higher risk of bleeding risk compared with that of wild-type allele carriers (TT, TC) and wild-type homozygote carriers (GG), respectively. Whereas the area under the receiver operating characteristic curve (AUROC) value using demographic factors only was 0.65 (95% confidence interval (CI): 0.56–0.74), the AUROC increased to 0.72 by adding genetic factors (95% CI: 0.65–0.80). The predicted bleeding risks of bleeding in patients with 0, 1, 2, 3, 4, 5, 6, 7 and 8 points from the logistic regression curve were 0.8%, 2.0%, 5.4%, 5.2%, 12.5%, 26.9%, 47.0%, 64.3% and 82.3%, respectively. Conclusions: The study results can be used for enhancing individualized treatment strategies in patients taking DOACs, helping clinicians predict the bleeding risk.

Laboratory Test Predictors for Major Bleeding in Elderly (≥80 Years) Patients With Nonvalvular Atrial Fibrillation Treated With Edoxaban 15 mg: Sub-Analysis of the ELDERCARE-AF Trial

Background

We investigated the predictors related to major bleeding events during treatment with edoxaban 15 mg in patients aged ≥80 years with nonvalvular atrial fibrillation and high bleeding risk, for whom standard oral anticoagulants are inappropriate, focusing on standard laboratory tests related to bleeding.

Methods and Results

This was a prespecified subanalysis of the on‐treatment analysis set of the ELDERCARE‐AF (Edoxaban Low‐Dose for Elder Care Atrial Fibrillation Patients) trial. Major bleeding was the primary safety end point. The event rates were calculated according to prespecified characteristics at baseline. A total of 984 Japanese patients were randomly assigned to edoxaban 15 mg or placebo (n=492, each). During the study period, 20 and 11 major bleeding events occurred in the edoxaban and placebo groups, respectively. The adjusted analysis revealed that hemoglobin <12.3 g/dL (adjusted hazard ratio [aHR], 3.57 [95% CI, 1.10–11.55]) and prothrombin time ≥12.7 seconds; (aHR, 2.89 [95% CI, 1.05–8.02]) independently predicted major bleeding, while creatinine clearance <30 mL/min showed a tendency towards an increase in major bleeding (aHR, 2.68; 95% CI, 0.96–7.46). In patients treated with edoxaban lacking these 3 risk factors, no major bleeding occurred; major bleeding event rates increased with each risk factor. Patients with 3 risk factors were significantly more likely to have a major bleeding event at 11.05%/year (HR, 7.15 [95% CI, 1.92–26.71]).

Conclusions

In elderly patients with nonvalvular atrial fibrillation with high bleeding risk, baseline hemoglobin <12.3 g/dL, prothrombin time ≥12.7 seconds, and creatinine clearance <30 mL/min may predict major bleeding during treatment with edoxaban 15 mg.

Registration

URL: ELDERCARE‐AF https://www.clinicaltrials.gov; Unique number: NCT02801669.

Anemia and iron deficiency in patients with atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac tachyarrhythmia and has a rising global prevalence. Given the increasing burden of AF-related symptoms and complications, new approaches to management are required. Anemia and iron deficiency are common conditions in patients with AF. Furthermore, emerging evidence suggests that the presence of anemia may be associated with worse outcome in these patients. The role of anemia and iron deficiency has been extensively explored in other cardiovascular states, such as heart failure and ischemic heart disease. In particular, the role of iron repletion amongst patients with heart failure is now an established treatment modality. However, despite the strong bidirectional inter-relationship between AF and heart failure, the implications of anemia and iron-deficiency in AF have been scarcely studied. This area is of mechanistic and clinical relevance given the potential that treatment of these conditions may improve symptoms and prognosis in the increasing number of individuals with AF. In this review, we summarise the current published literature on anemia and iron deficiency in patients with AF. We discuss AF complications such as stroke, bleeding, and heart failure, in addition to AF-related symptoms such as exercise intolerance, and the potential impact of anemia and iron deficiency on these. Finally, we summarize current research gaps on anemia, iron deficiency, and AF, and underscore potential research directions.

Associations of anemia with death and major bleeding in patients with atrial fibrillation: A report from the Chinese Atrial Fibrillation Registry Study

Background

Anemia is a common comorbidity in patients with atrial fibrillation (AF). Reports on the association of anemia and adverse events in patients with AF, especially from Asia, are limited.

Methods and Results

Based on data from the Chinese Atrial Fibrillation Registry Study (CAFR), a total of 18,106 AF patients enrolled between August 2011 and December 2018 had hemoglobin (Hb) values recorded at baseline. Patients were classified into three groups according to Hb levels: 15,606 patients (86.2%) into the no anemia group (male Hb≥130 g/L; female Hb≥120 g/L), 1800 (9.9%) with mild anemia (male 110≤Hb<129 g/L; female 110≤Hb<119 g/L), and 700 (3.9%) with moderate to severe anemia (Hb≤109 g/L). Multivariable Cox regression models were used to determine if anemia was independently associated with all‐cause death, cardiovascular death, or major bleeding, after adjusting for confounders.

Anemia was present in 13.8% of the population at baseline. During a median follow‐up of 4.01 years, the incidences of all‐cause death (1.8, 4.9, and 8.9 per 100 person‐years), cardiovascular death (1.0, 2.9, and 4.5 per 100 person‐years), and major bleeding (0.5, 0.6, and 0.7 per 100 person‐years) were gradually accentuated in patients with no anemia, mild anemia, and moderate to severe anemia, respectively. Compared with patients with no anemia, those with anemia had higher risks for all‐cause death (mild anemia; adjusted hazard ratio [HR]: 1.22, 95% confidence interval [CI]: 1.08–1.38; moderate to severe anemia; adjusted HR: 1.53, 95% CI: 1.31–1.77); and cardiovascular death (mild anemia; adjusted HR: 1.29, 95% CI: 1.10–1.52; moderate to severe anemia; adjusted HR: 1.27, 95% CI: 1.03–1.57), but not for major bleeding. The association between anemia and all‐cause death was similar among subgroups stratified by sex, kidney function, anticoagulant, or ablation therapy.

Conclusions

Anemia was associated with increased risks of all‐cause death, cardiovascular death, but no major bleeding in AF patients. The effect of anemia correction on the prognosis of patients with AF requires further study.

Rationale and design of the IRON-AF study: a double-blind, randomised, placebo-controlled study to assess the effect of intravenous ferric carboxymaltose in patients with atrial fibrillation and iron deficiency

INTRODUCTION

Atrial fibrillation (AF) is associated with significantly impaired quality-of-life. Iron deficiency (ID) is prevalent in patients with AF. Correction of ID in other patient populations with intravenous iron supplementation has been shown to be a safe, convenient and effective way of improving exercise tolerance, fatigue and quality-of-life. The IRON-AF (Effect of Iron Repletion in Atrial Fibrillation) study is designed to assess the effect of iron repletion with intravenous ferric carboxymaltose in patients with AF and ID.

METHODS AND ANALYSIS

The IRON-AF study is a double-blind, randomised controlled trial that will recruit at least 84 patients with AF and ID. Patients will be randomised to receive infusions of either ferric carboxymaltose or placebo, given in repletion and then maintenance doses. The study will have follow-up visits at weeks 4, 8 and 12. The primary endpoint is change in peak oxygen uptake from baseline to week 12, as measured by cardiopulmonary exercise testing (CPET) on a cycle ergometer. Secondary endpoints include changes in quality-of-life and AF disease burden scores, blood parameters, other CPET parameters, transthoracic echocardiogram parameters, 6-minute walk test distance, 7-day Holter/Event monitor burden of AF, health resource utilisation and mortality.

ETHICS AND DISSEMINATION

The study protocol has been approved by the Central Adelaide Local Health Network Human Research Ethics Committee, Australia. The results of this study will be disseminated through publications in peer-reviewed journals and conference presentations.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry (ACTRN12620000285954).