A retrospective study on atrial fibrillation after coronary artery bypass grafting surgery at The National Heart Institute, Kuala Lumpur

Optimizing Anticoagulation Strategies in Patients With Atrial Fibrillation and Valvular Heart Disease: A Comprehensive Evidence-Based Review

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, significantly increases the risk of thromboembolism and stroke. Its coexistence with valvular heart disease (VHD) further complicates management due to elevated risks of thromboembolism, bleeding, and mortality. This review explores the pathophysiology of AF and its interaction with VHD, focusing on diagnostic tools like echocardiography and risk stratification scores such as CHA2DS2-VASc and HAS-BLED. Vitamin K antagonists (VKAs) remain the cornerstone of anticoagulation therapy in high-risk VHD populations, particularly in patients with mechanical heart valves or moderate-to-severe mitral stenosis (MS). VKAs have demonstrated proven efficacy in reducing thromboembolic events in these subgroups, supported by decades of clinical evidence. However, their use requires frequent international normalized ratio (INR) monitoring and is associated with higher bleeding risks, posing challenges in long-term management. Despite these limitations, VKAs are indispensable in these populations due to the lack of robust evidence supporting the safety and efficacy of direct oral anticoagulants (DOACs) in these high-risk groups. Ongoing clinical trials, such as the RIVER trial, aim to evaluate the role of DOACs in VHD. However, current guidelines continue to recommend VKAs as the standard of care for these patients. In contrast, DOACs offer significant advantages in non-valvular AF and selected VHD populations. Their predictable pharmacokinetics, fewer dietary restrictions, and lower risks of intracranial hemorrhage make them a preferred choice for many patients. Landmark trials and meta-analyses, including RE-LY, ROCKET-AF, and ARISTOTLE, have demonstrated the safety and efficacy of DOACs in non-valvular AF and certain VHD subgroups. However, DOACs are contraindicated in high-risk VHD populations, such as those with mechanical valves or moderate-to-severe MS, due to insufficient evidence and potential risks of thromboembolic events. Evolving guidelines from leading societies emphasize individualized approaches and collaborative decision-making in anticoagulation therapy. While DOACs are preferred for most AF patients, VKAs remain essential for high-risk VHD patients. Future advancements, such as factor XIa inhibitors, hold promise for improving outcomes and safety in these complex populations. This review provides a comprehensive framework for clinicians to navigate the complexities of anticoagulation in AF and VHD, ensuring evidence-based, patient-centered care.

Atrial Fibrillation After Coronary Artery Bypass Grafting and Its Relationship with Hospital Complications in São Paulo State

INTRODUCTION

Atrial fibrillation is the main complication in the postoperative period of cardiovascular surgery. Its genesis is multifactorial, so its rapid identification to mitigate the associated risks is essential.

OBJECTIVE

To evaluate the incidence of atrial fibrillation in patients undergoing coronary artery bypass grafting (CABG) and its relationship with other complications in our setting.

METHODS

This is a multicenter, observational study involving patients undergoing isolated CABG between 2017 and 2019 with data from the Registro Paulista de Cirurgia Cardiovascular (or REPLICCAR II). Variables were prospectively collected in REDCap following the definitions given by version 2.73 of the Society of Thoracic Surgeons Adult Cardiac Surgery Database. Data were collected with prior authorization from the local ethics committee and analyses performed in R software.

RESULTS

A total of 3,803 patients were included, of these 605 had postoperative atrial fibrillation (POAF). In order to adjust the groups, propensity score matching was used. Such analyses resulted in 605 patients in each group (without POAF vs. with POAF). Among patients with POAF, the mean age was 67.56 years, with a prevalence of males (73.6%, 445 patients). Patients belonging to the group with POAF had a mortality rate of 9.26% (P=0.007), longer ventilation time (P<0.001), pneumonia (P<0.001), and sepsis (P<0.001). In multiple analysis, acute renal dysfunction (P=0.032) and longer intensive care unit stay (P<0,001) were associated with the presence of POAF.

CONCLUSION

POAF in CABG is associated with longer intensive care unit and hospital stay, as well as renal dysfunction, pneumonia, and in-hospital mortality.

Predictors of Developing Postoperative Atrial Fibrillation in Patients Undergoing Coronary Artery Bypass Graft: A Systematic Review and Meta-Analysis

The objective of this study was to determine predictors of postoperative atrial fibrillation (POAF) among coronary artery bypass graft (CABG) patients. This meta-analysis was conducted as per the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). Two authors performed searches independently using electronic databases, including Embase, PubMed, and Web of Science, from January 1, 2015, to November 30, 2023. A total of 16 studies were included in this meta-analysis. All included studies reported POAF in patients undergoing CABG, resulting in 1462 cases of POAF among 6200 patients undergoing CABG. The cases of POAF varied among studies, ranging from 7.80% to 47.37%. The pooled incidence of POAF was 26% (95% CI: 20% to 31%). The results indicated that older patients had a higher risk of developing atrial fibrillation (AF) after CABG (mean difference [MD]): 5.63, 95% confidence interval (CI): 4.08 to 7.17, p-value < 0.001). The findings revealed a significantly lower left ventricular ejection fraction (LVEF) in patients developing AF than their counterparts (MD: -0.30, 95% CI: -0.58 to -0.03, p-value: 0.03). Regarding the history of myocardial infarction (MI), the odds of MI were significantly higher in patients developing AF compared to those who did not develop AF (odds ratio [OR]: 1.37, 95% CI: 1.12 to 1.68, p-value: 0.002). In relation to intra-aortic balloon pump (IABP), the odds of IABP were significantly higher in patients developing AF compared to those who did not develop AF (OR: 2.27, 95% CI: 1.39 to 3.72, p-value: 0.001). Identified risk factors for post-CABG AF included advanced age, a lower preoperative ejection fraction, a history of myocardial infarction, the requirement for an IABP, and prolonged cardiopulmonary bypass (CPB) time. The study underscores the significance of proactive screening and comprehensive management for elderly CABG patients, particularly those with myocardial infarction histories.

A double-blind randomised controlled trial on the effect of Tocovid, a tocotrienol-rich capsule on postoperative atrial fibrillation at the National Heart Institute, Kuala Lumpur: an interim blinded analysis

INTRODUCTION

Post-operative atrial fibrillation (POAF) is associated with poorer outcomes, increased resource utilisation, morbidity and mortality. Its pathogenesis is initiated by systemic inflammation and oxidative stress. It is hypothesised that a potent antioxidant and anti-inflammatory agent such as tocotrienol, an isomer of Vitamin E, could reduce or prevent POAF.

AIMS

The aim of this study is to determine whether a potent antioxidative and anti-inflammatory agent, Tocovid, a tocotrienol-rich capsule, could reduce the incidence of POAF and affect the mortality and morbidity as well as the duration of ICU, HDU and hospital stay.

METHODS

This study was planned as a prospective, randomised, controlled trial with parallel groups. The control group received placebo containing palm superolein while the treatment group received Tocovid capsules. We investigated the incidence of POAF, the length of hospital stay after surgery and the health-related quality of life.

RESULTS

Recruitment commenced in January 2019 but the preliminary results were unblinded as the study is still ongoing. Two-hundred and two patients have been recruited out of a target sample size of 250 as of January 2021. About 75% have completed the study and 6.4% were either lost during follow-up or withdrew; 4% of participants died. The mean age group was 61.44 ± 7.30 years with no statistical difference between the groups, with males having a preponderance for AF. The incidence of POAF was 24.36% and the mean time for developing POAF was 55.38 ± 29.9 h post-CABG. Obesity was not a predictive factor. No statistically significant difference was observed when comparing left atrial size, NYHA class, ejection fraction and the premorbid history. The mean cross-clamp time was 71 ± 34 min and the mean bypass time was 95 ± 46 min, with no difference between groups. There was a threefold increase in death among patients with POAF (p = 0.008) and an increase in the duration of ICU stay (p = 0.01), the total duration of hospital stay (p = 0.04) and reintubation (p = 0.045).

CONCLUSION

A relatively low incidence rate of POAF was noted although the study is still ongoing. It remains to be seen if our prophylactic intervention using Tocovid would effectively reduce the incidence of POAF. Clinical Registration Number: US National Library of Medicine. Clinical Trials - NCT03807037. Registered on 16th January 2019. Link: https://clinicaltrials.gov/ct2/show/NCT03807037.