Novel Oral Anticoagulants Compared to Warfarin for Postoperative Atrial Fibrillation After Isolated Coronary Artery Bypass Grafting

Anticoagulation for post-operative atrial fibrillation after isolated coronary artery bypass grafting: a meta-analysis

BACKGROUND AND AIMS

This study aimed to evaluate clinical outcomes in patients developing post-operative atrial fibrillation (POAF) after coronary artery bypass grafting (CABG) and characterize variations in oral anticoagulation (OAC) use, benefits, and complications.

METHODS

A systematic search identified studies on new-onset POAF after CABG and OAC initiation. Outcomes included risks of thromboembolic events, bleeding, and mortality. Furthermore, a meta-analysis was conducted on these outcomes, stratified by the use or non-use of OAC.

RESULTS

The identified studies were all non-randomized. Among 1 698 307 CABG patients, POAF incidence ranged from 7.9% to 37.6%. Of all POAF patients, 15.5% received OAC. Within 30 days, thromboembolic events occurred at rates of 1.0% (POAF: 0.3%; non-POAF: 0.8%) with 2.0% mortality (POAF: 1.0%; non-POAF: 0.5%). Bleeding rates were 1.1% for POAF patients and 2.7% for non-POAF patients. Over a median of 4.6 years, POAF patients had 1.73 thromboembolic events, 3.39 mortality, and 2.00 bleeding events per 100 person-years; non-POAF patients had 1.14, 2.19, and 1.60, respectively. No significant differences in thromboembolic risks [effect size -0.11 (-0.36 to 0.13)] and mortality [effect size -0.07 (-0.21 to 0.07)] were observed between OAC users and non-users. However, OAC use was associated with higher bleeding risk [effect size 0.32 (0.06-0.58)].

CONCLUSIONS

In multiple timeframes following CABG, the incidence of complications in patients who develop POAF is low. The use of OAC in patients with POAF after CABG is associated with increased bleeding risk.

Safety and Efficacy of Non-Vitamin K Oral Anticoagulant Use Early After Cardiac Surgery: A Systematic Review

OBJECTIVE

To determine the safety and efficacy of non-vitamin K oral anticoagulants (NOACs) initiated early after cardiac surgery.

DATA SOURCES:

Cochrane Central Register of Controlled Trials, EMBASE, and MEDLINE (database inception to January 20, 2021), www.clinicaltrials.gov, www.who.int/ictrp/search/en/, NOAC trial registries, and bibliographies of relevant guidelines and other reviews were used.

STUDY SELECTION AND DATA EXTRACTION

Observational studies and randomized controlled trials (RCTs) that initiated NOACs within the index hospitalization and that reported bleeding for the primary outcome were included.

DATA SYNTHESIS

A total of 6 cohort studies, 1 RCT, and 3 ongoing RCTs were included. Most studies were single-centered, limited to postoperative atrial fibrillation after coronary artery bypass grafting, and with 30-day follow-up; few studies included patients with isolated bioprosthetic valve replacement or valve repair. Bleeding risk varied (0%-28.6%), and all but one study showed no significantly higher risk with NOAC compared with warfarin.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Overall, NOACs were used in 26% to 37.5% of patients early after cardiac surgery. Starting a NOAC on postoperative day 4 appeared to have similar bleeding rates compared with warfarin, but clinical application is limited by heterogeneity of outcome definitions, confounding, and bias. Compared with warfarin, NOACs may have similar thromboembolism risk, reduced length of stay, and cost.

CONCLUSIONS

There is limited evidence to guide NOAC use early after cardiac surgery. Three ongoing randomized trials will add to the literature and provide guidance for clinicians on whether, in whom, when, and how to use NOACs safely early after cardiac surgery.

Postoperative Atrial Fibrillation and Long-Term Risk of Stroke After Isolated Coronary Artery Bypass Graft Surgery

BACKGROUND

Postoperative atrial fibrillation (pAF) after coronary artery bypass grafting is a common complication. Whether pAF is associated with an increased risk of cerebrovascular accident (CVA) remains uncertain. We investigated the association between pAF and long-term risk of CVA by performing a post hoc analysis of 10-year outcomes of the ART (Arterial Revascularization Trial).

METHODS

For the present analysis, among patients enrolled in the ART (n=3102), we excluded those who did not undergo surgery (n=25), had a history of atrial fibrillation (n=45), or had no information on the incidence of pAF (n=9). The final population consisted of 3023 patients, of whom 734 (24.3%) developed pAF with the remaining 2289 maintaining sinus rhythm. Competing risk and Cox regression analyses were used to investigate the association between pAF and the risk of CVA.

RESULTS

At 10 years, the cumulative incidence of CVA was 6.3% (4.6%-8.1%) versus 3.7% (2.9%-4.5%) in patients with pAF and sinus rhythm, respectively. pAF was an independent predictor of CVA at 10 years (hazard ratio, 1.53 [95% CI, 1.06-2.23]; P=0.025) even when CVAs that occurred during the index admission were excluded from the analysis (hazard ratio, 1.47 [95% 1.02-2.11]; P=0.04).

CONCLUSIONS

Patients with pAF after coronary artery bypass grafting are at higher risk of CVA. These findings challenge the notion that pAF is a benign complication.

Comparison of novel oral anticoagulants versus warfarin for post-operative atrial fibrillation after coronary artery bypass grafting

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was ‘Does the use of Novel Oral Anticoagulants (NOACs) result in more complications than Warfarin for treatment of post-operative atrial fibrillation (AF) following coronary artery bypass grafting (CABG)?’ Altogether more than 93 papers were found using the reported search with 4 studies representing the best evidence to answer the clinical question, including 1 randomised trial and 3 retrospective case-control studies. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers were tabulated. Timing for initiation of anticoagulation was similar across the studies, with both demonstrating longer hospital stays and greater time to reach therapeutic anticoagulation in the warfarin cohort. Three studies reported similar safety between the two groups. One study revealed significantly more invasive interventions for pleural or pericardial effusions in the NOAC group, whilst in contrast another study demonstrated a higher rate of major bleeding in the warfarin cohort. Cost-analysis revealed that NOACs were overall more cost-effective compared to warfarin despite the higher cost for the medication itself. In conclusion, the use of NOACs after CABG for post-operative AF can be used as an alternative to warfarin, however, one should remain vigilant for possible pericardial or pleural effusions which may require reintervention. Further dedicated research and larger appropriately powered randomised control trials are needed to confirm the safety of NOACs in post-cardiac surgery patients.

•

Atrial fibrillation (AF) is the most common arrhythmia post cardiac surgery.

•

While usually self-limiting, AF has increased morbidity and mortality to patients.

•

Anticoagulation is warranted if AF is persistent or recurrent.

•

Warfarin has been the mainstay of therapy, however, NOACs have gained popularity.

•

The safety of NOACs in post-cardiac surgery patients is so far poorly defined.