Registry of antithrombotic therapy in atrial fibrillation patients with bioprosthetic valves: A retrospective observational study

Direct Oral Anticoagulation Versus Warfarin in Patients with Atrial Fibrillation and Bioprosthetic Heart Valves: a Retrospective, Real-World Cohort Study

OBJECTIVE

In this retrospective cohort study of consecutive patients with atrial fibrillation and surgical or transcatheter bioprosthetic valve, we compared the efficacy and safety of direct oral anticoagulants with warfarin.

METHODS

Using linked health administrative databases housed at the Institute for Clinical Evaluative Sciences, we identified consecutive patients in Ontario (Canada) 65 years of age or older with AF who underwent bioprosthetic valve replacement between 1 April 2012 and 31 March 2017. We created a time-varying Cox model to examine the relationship between the type of anticoagulant and time to thrombotic or bleeding events after adjustment for baseline risk of thrombosis using the CHA2DS2-VASc score and risk of bleeding using the HAS-BLED scores. We conducted prespecified subgroup analyses according to whether valve implantation was surgical or transcatheter.

RESULTS

We identified 2245 eligible patients. The mean age was 79 years, 41% were female, and 39% had transcatheter aortic valve replacement. Risk of death or thrombosis was not different between direct oral anticoagulants and warfarin after adjustment for CHA2DS2-VASc score (hazard ratio [HR] 1.02, 95% confidence interval [CI], 0.83-1.25). Risk of death or bleeding was not different between direct oral anticoagulants and warfarin after adjustment for HAS-BLED score (HR 0.89, 95% CI 0.75-1.07). Subgroup analyses of surgical or transcatheter valves were consistent with overall results.

CONCLUSIONS

In a real-world population of patients with atrial fibrillation and bioprosthetic valve replacement, we found no difference between direct oral anticoagulants and warfarin with regard to the risk of thrombosis or bleeding.

An Evidence-Based Approach to Anticoagulation Therapy Comparing Direct Oral Anticoagulants and Vitamin K Antagonists in Patients With Atrial Fibrillation and Bioprosthetic Valves: A Systematic Review, Meta-Analysis, and Network Meta-Analysis

Direct oral anticoagulants (DOACs) are a newer class of anticoagulants that inhibit factor Xa or factor IIa and include drugs such as rivaroxaban, apixaban, edoxaban, betrixaban, and dabigatran. Although vitamin K antagonists (VKAs) have been traditionally used to prevent thromboembolic events, DOACs have gained popularity because of their faster onset and offset of action and reduced need for monitoring. This study aimed to provide more data for anticoagulants in patients with atrial fibrillation with bioprosthetic heart valves by incorporating all available trials to date. A search was performed across 5 electronic databases to identify relevant studies. We analyzed the data using a pooled risk ratio for categorical outcomes and used the I2 test to determine heterogeneity. The quality of randomized controlled trials was assessed using the Cochrane risk of bias assessment tool, and the National Institutes of Health tool was used for observational studies. Our study included a frequentist network meta-analysis (MA) of the aggregate data to obtain the network estimates for the outcomes of interest. We retrieved 28 studies with a total of 74,660 patients with bioprosthetic heart valves. Our MA significantly showed that DOACs decrease the risk of all-cause bleeding (risk ratio [RR] 0.80, 95% confidence interval [CI] 0.75 to 0.85, p >0.00001), stroke and systemic embolization (RR 0.89, 95% CI 0.80 to 0.99, p = 0.03), and intracranial bleeding outcomes (RR 0.62, 95% CI 0.45 to 0.86, p = 0.004) compared with VKA. In contrast, there was no significant difference between the compared groups in major bleeding (RR = 0.92, 95% CI 0.84 to 1.02, p = 0.10) and all-cause mortality outcomes (RR = 0.96, 95% CI 0.85 to 1.07, p = 0.43), respectively. In addition, the network MA results did not favor any of the studied interventions over each other (p <0.05) regarding all-cause bleeding, mortality, stroke and systemic embolization, and major bleeding outcomes. In conclusion, our study found that DOACs are more effective in reducing the risk of bleeding, stroke, systemic embolism, and intracranial bleeding than VKAs. However, no significant difference was observed in the incidence of gastrointestinal bleeding, major bleeding, thromboembolic events, and all-cause mortality. In addition, our network MA did not identify any specific DOAC treatment as more favorable than others.

Direct oral anticoagulation in atrial fibrillation and heart valve surgery-a meta-analysis and systematic review

AIMS

Oral anticoagulation with direct oral anticoagulants (DOAC) could provide an alternative to vitamin K antagonists (VKA) for patients with atrial fibrillation (AF) undergoing bioprosthetic heart valve replacement or valve repair.

METHODS AND RESULTS

The aim of this meta-analysis was to review the safety and efficacy of DOAC in patients with surgical implanted bioprosthetic heart valves or valve repairs and AF including data from six clinical trials with a total of 1,857 patients. The efficacy and safety data of DOAC and VKA were pooled to perform random-effects meta-analyses using the Mantel-Haenszel method with pooled risk ratios (RR) and 95% confidence interval (CI). A trial sequential analysis (TSA) was performed to assess statistical robustness. Death caused by cardiovascular cause or thromboembolic events were comparable (RR 0.67, 95% CI: 0.42-1.08; p = 0.10) as DOAC significantly reduced the risk for major bleeding (RR 0.55, 95% CI: 0.35-0.88; p = 0.01) and thromboembolic stroke or systemic embolism rates (RR 0.54, 95% CI: 0.32-0.90; p = 0.02). Rates for intracranial bleeding and hemorrhagic stroke (RR 0.27, 95% CI: 0.07-0.99; p = 0.05) show a trend toward fewer events in the DOAC group. Outcomes for major or minor bleeding events and all-cause mortality were comparable for DOAC and VKA.

CONCLUSION

Cumulative data analysis reveals that DOAC may provide an effective and safe alternative to VKA in patients with AF after surgically implanted bioprosthetic heart valves or repair with AF. Within a relatively heterogeneous study population, this meta-analysis shows a risk reduction of major bleedings and thromboembolic stroke or systemic embolisms for DOAC.

Additional Effects of Antiplatelet Therapy on Anticoagulant Agents in Patients With Bioprosthetic Valves and Atrial Fibrillation

BACKGROUND

The additional effects of single-antiplatelet therapy (SAPT) on anticoagulant therapy are still unclear in patients with atrial fibrillation (AF) after bioprosthetic valve replacement.Methods and Results:We conducted a subanalysis of a multicenter, retrospective, observational registry of patients with bioprosthetic valves and AF in Japan. Patients administered anticoagulants alone comprised the ACA group (n=107), and patients given concomitant SAPT and anticoagulant therapy comprised the On SAPT group (n=82). The primary efficacy endpoint was the incidence of stroke/systemic embolism, and the primary safety endpoint was the incidence of major bleeding. The observation period was 46.3±24.6 months. The primary efficacy endpoint occurred in 12 patients, and the cumulative incidence of primary efficacy events was significantly higher in the ACA group compared with the On SAPT group (P=0.039). The primary safety endpoint occurred in 22 patients, and the cumulative incidence of primary safety events was similar between groups (P=0.66). No differences between the groups were observed for cardiac events.

CONCLUSIONS

Additional SAPT on anticoagulant therapy in patients with bioprosthetic valves and AF was associated with a reduction in stroke/systemic embolic events, although the cumulative incidence of bleeding was similar, regardless of additional SAPT. These findings suggest that additional SAPT on anticoagulant therapy may be safe and effective in real-world clinical settings.

Safety and Efficacy of Apixaban Following Bioprosthetic Valve Replacements: A Retrospective Evaluation

Background: Data on the use of direct oral anticoagulants in the setting of bioprosthetic valve replacements is limited. Objective: The purpose of this study was to describe outcomes among patients who underwent a bioprosthetic valve replacement and were subsequently prescribed apixaban. Methods: A retrospective cohort study was completed for inpatients at a community hospital who were prescribed apixaban following a bioprosthetic valve replacement from 2015 to 2020. Endpoints assessed included incidence of all-cause readmission and emergency visits within 3 months following valvular surgery, incidence of mortality, and all-cause major and minor bleeding. A post hoc analysis was conducted comparing outcomes among patients who underwent mitral versus aortic valve replacement, as well as patients with and without atrial fibrillation. The study was deemed exempt by hospital and university institutional review boards. Results: A total of 54 patients were included for analysis. All-cause readmission or emergency visit occurred in 33% (n = 18) of patients and the mortality rate was 6% (n = 3). A minor bleeding event was reported in 6% (n = 3) of patients and a major bleeding event was reported in 2% (n = 1) of patients. A thrombotic event was reported in 2% (n = 1) of patients. Conclusion: Within this cohort of patients requiring anticoagulation following bioprosthetic valve replacement, apixaban was safe and well-tolerated. However, more prospective data are needed to further correlate the safety and efficacy of apixaban, particularly in the setting of mitral valve replacement.

Antithrombotic Therapy for Patients With Atrial Fibrillation and Bioprosthetic Valves - Real-World Data From the Multicenter, Prospective, Observational BPV-AF Registry

BACKGROUND

Although bioprosthetic valve (BPV) replacements are becoming more common within our aging society, there are limited prospective data on the appropriate antithrombotic therapy for East Asian patients with atrial fibrillation (AF) and BPV replacement. Antithrombotic therapy and thrombotic and hemorrhagic event rates in Japanese patients with AF and BPV replacement are investigated.Methods and Results:This multicenter, prospective, observational study enrolled patients with BPV replacement and AF. The primary efficacy outcome was stroke or systemic embolism, and the primary safety outcome was major bleeding. Of the 894 patients analyzed, 54.7%, 29.4%, and 9.6%, were treated with warfarin-based therapy, direct oral anticoagulant (DOAC)-based therapy, or antiplatelet therapy without anticoagulants, respectively; 6.3% did not receive any antithrombotic drugs. The mean observation period was 15.3±4.0 months. The event rates for stroke or systemic embolism and major bleeding were 1.95%/year and 1.86%/year, respectively. The multivariate adjusted hazard ratios for DOAC vs. warfarin were 1.02 (95% confidence intervals [CI], 0.30-3.41 [P=0.979]) for systemic embolic events and 0.96 (95% CI, 0.29-3.16 [P=0.945]) for major bleeding.

CONCLUSIONS

Approximately 30% of patients with AF and BPV replacement were treated with DOAC. The risks of major bleeding and stroke or systemic embolism were similar between warfarin- and DOAC-treated patients with AF who had BPV replacement. Treatment with DOACs could be an alternative to warfarin in this population.

Impact of mitral versus aortic bioprosthetic valve position on thromboembolism and bleeding risk in patients with atrial fibrillation

BACKGROUND

The impact of valve position on thromboembolic and bleeding events in patients with atrial fibrillation (AF) and bioprosthetic valves is uncertain.

METHODS

We analyzed 159 patients with AF after surgical single-valve replacement from the BPV-AF registry (Retro) (UMIN000034198), which was a multicenter, retrospective, observational registry that enrolled 214 patients with AF and bioprosthetic valves to assess differences in bioprosthetic valve position. Baseline characteristics and clinical outcomes were compared on the basis of the position of aortic or mitral bioprosthetic valves. The primary efficacy endpoint was stroke or systemic embolism, and the primary safety endpoint was major bleeding.

RESULTS

There were 85 patients (53.5%) in the aortic valve (AV) group and 74 patients (46.5%) in the mitral valve (MV) group. The MV group had a lower body weight and a higher prevalence of prior major bleeding compared with the AV group. Thromboembolic and bleeding risk scores and the administration of antithrombotic agents were not significantly different between the groups. The primary efficacy endpoint was not significantly different [AV group: 8.2%; 2.25/100 person-years (PY); MV group: 4.1%; 1.01/100 PY] (log-rank, p = 0.23). The primary safety endpoint was significantly higher in the MV group (17.6%; 4.54/100 PY) compared with the AV group (5.9%; 1.59/100 PY) (log-rank, p = 0.049). The adjusted hazard ratio of the primary safety endpoint in the MV group relative to the AV group was 2.71 (95% confidence interval 0.86-8.54, p = 0.09).

CONCLUSIONS

In Japanese patients with AF and bioprosthetic valves, thromboembolic risk does not differ on the basis of valve position. Bleeding risk is higher in patients with MV bioprostheses, although valve position itself might not be an independent predictor for bleeding.

Long-Term Stability and Biocompatibility of Pericardial Bioprosthetic Heart Valves

The use of bioprostheses for heart valve therapy has gradually evolved over several decades and both surgical and transcatheter devices are now highly successful. The rapid expansion of the transcatheter concept has clearly placed a significant onus on the need for improved production methods, particularly the pre-treatment of bovine pericardium. Two of the difficulties associated with the biocompatibility of bioprosthetic valves are the possibilities of immune responses and calcification, which have led to either catastrophic failure or slow dystrophic changes. These have been addressed by evolutionary trends in cross-linking and decellularization techniques and, over the last two decades, the improvements have resulted in somewhat greater durability. However, as the need to consider the use of bioprosthetic valves in younger patients has become an important clinical and sociological issue, the requirement for even greater longevity and safety is now paramount. This is especially true with respect to potential therapies for young people who are afflicted by rheumatic heart disease, mostly in low- to middle-income countries, for whom no clinically acceptable and cost-effective treatments currently exist. To extend longevity to this new level, it has been necessary to evaluate the mechanisms of pericardium biocompatibility, with special emphasis on the interplay between cross-linking, decellularization and anti-immunogenicity processes. These mechanisms are reviewed in this paper. On the basis of a better understanding of these mechanisms, a few alternative treatment protocols have been developed in the last few years. The most promising protocol here is based on a carefully designed combination of phases of tissue-protective decellularization with a finely-titrated cross-linking sequence. Such refined protocols offer considerable potential in the progress toward superior longevity of pericardial heart valves and introduce a scientific dimension beyond the largely disappointing 'anti-calcification' treatments of past decades.

The Characteristics, Long-Term Outcomes, Risk Factors, and Antithrombotic Therapy in Chinese Patients With Atrial Fibrillation and Bioprosthetic Valves

Introduction: There were few data about the clinical profiles and long-term outcomes in Chinese patients with atrial fibrillation (AF) and bioprosthetic valves.

Methods: The retrospective study enrolled 903 patients with bioprosthetic valve replacement at our hospital and discharged with a diagnosis of AF from January 2010 to December 2018.

Results: The median age was 65.6 (61.9–69.1) years, and 548 (60.7%) patients were women. During a follow-up period of 3.84 (2.64–5.51) years, 68 (1.8 per 100 person-years) patients died, 81 (2.1 per 100 person-years) patients developed thromboembolism, and 23 (0.6 per 100 person-years) patients experienced major bleeding. The CHA₂DS₂-VASc score, as a categorical variable (low, moderate, or high risk), predicted the risk of thromboembolism with the C-statistic of 0.6 (95% CI: 0.511–0.689, p = 0.046). The incidence of the CHA₂DS₂-VASc score increment was 11.6 per 100 person-years, and the annual reclassification rate of stroke risk (from a low or moderate group to a higher group) was 12.7%. The current proportion of oral anticoagulants was 52.3, 59, and 63.2%, respectively, in the low, moderate, and high stroke risk groups. Age (OR: 1.04, 95% CI: 1.01–1.06, p = 0.01), left atrial size (OR: 1.05, 95% CI: 1.03–1.08, p < 0.001), and rheumatic heart disease (OR: 1.49, 95% CI: 1.05–2.10, p = 0.025) were positively associated with the use of oral anticoagulants. The history of chronic kidney disease (OR: 0.20, 95% CI: 0.05–0.76, p = 0.018), prior surgical ablation (OR: 0.33, 95% CI: 0.24–0.47, p < 0.001), and antiplatelet agent use (OR: 0.08, 95% CI: 0.05–0.13, p < 0.001) were inversely related to the use of oral anticoagulants. Higher admission estimated glomerular filtration rate (HR: 0.515, 95% CI: 0.311–0.853, p = 0.01), left ventricular ejection fraction (HR: 0.961, 95% CI: 0.931–0.992, p = 0.014), concomitant surgical ablation (HR: 0.348, 95% CI: 0.171–0.711, p = 0.004), and rheumatic heart disease history (HR: 0.515, 95% CI: 0.311–0.853, p = 0.01) were associated with a lower risk of death. Surgical ablation (HR: 0.263, 95% CI: 0.133–0.519, p < 0.001) and oral anticoagulants (HR: 0.587, 95% CI: 0.375–0.918, p = 0.019) were related to a lower risk of thromboembolism.

Conclusion: Chinese patients with AF and bioprosthetic valve(s) were relatively young and had a high prevalence of rheumatic heart disease with few comorbidities. The percentage of mitral bioprosthetic valve replacement was high. The proportion of concomitant surgical ablation or surgical left atrial appendage occlusion or exclusion was relatively low. The thromboembolic events were the major long-term adverse events. The anticoagulation therapy was underused in patients at moderate or high stroke risk. The CHA₂DS₂-VASc score was verified to be used for predicting stroke risk in this population. The stroke risk dynamically changed; it needed to be reestimated once the risk factor changed.

Rationale, Design, and Baseline Characteristics of the BioProsthetic Valves with Atrial Fibrillation (BPV-AF) Study

PURPOSE

To date, clinical data on real-world treatment practices in Japanese patients with atrial fibrillation (AF) after bioprosthetic valve (BPV) replacement are needed. We conducted a large-scale, prospective, multicenter study to understand the actual usage of antithrombotic therapy and the incidence of thromboembolic and bleeding events in these patients, and to eliminate the clinical data gap between Japan and Western countries.

METHODS

This was an observational study, in patients who had undergone BPV replacement and had a confirmed diagnosis of AF, with no mandated interventions. We report the baseline demographic and clinical data for the 899 evaluable patients at the end of the enrollment period.

RESULTS

Overall, 45.7% of patients were male; the mean age was 80.3 years; AF was paroxysmal, persistent, or permanent in 36.9%, 34.6%, and 28.5% of patients, respectively. Mean risk scores for stroke and bleeding were 2.5 (CHADS2), 4.1 (CHA2DS2-VASc), and 2.5 (HAS-BLED). Many patients (76.2%) had comorbid hypertension and 54.8% had heart failure. Most BPVs (65.5%) were positioned in the aortic valve. Warfarin-based therapy, direct oral anticoagulant (DOAC)-based therapy, and antiplatelet therapy (without warfarin and DOAC) were administered to 55.0%, 29.3%, and 9.7% of patients, respectively.

CONCLUSION

Patients enrolled into this study are typical of the wider Japanese AF/BPV population in terms of age and clinical history. Future data accruing from the observational period will contribute to future treatment recommendations and guide therapeutic decisions in patients with BPV and AF.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: UMIN000034485.