Lessons from the RE-ALIGN trial

Systematic Review and Meta-Analysis: Can We Compare Direct Oral Anticoagulants to Warfarin in Patients With Atrial Fibrillation and Bio-Prosthetic Valves?

Background

There are no clear consensus guidelines on the indications and types of anticoagulation therapies in patients with bio-prosthetic valves either with concomitant atrial fibrillation (AF) or sinus rhythm. In our meta-analysis, we assessed the safety and efficacy of DOACs as compared to the standard treatment with warfarin in patients with AF and bioprosthetic valves.

Methods

We included randomized controlled trials (RCTs), cohort studies in the English language, and studies reporting patients with valvular heart disease that included bioprosthetic valvular disease. A systematic literature review using Embase, PubMed, and Web of Science was performed using the terms “Direct Acting Oral Anticoagulant,” “Oral Anticoagulants,” “Non-Vitamin K Antagonist Oral Anticoagulant,” “Atrial Fibrillation,” “Bioprosthetic Valve” for literature published prior to January 2021. Extraction of data from included studies was carried out independently by three reviewers from Covidence. We assessed the methodical rigor of the included studies using the modified Downs and Black checklist.

Results

Four RCTs and one observational study (n=1776) were included in our study. A random-effect model using RevMan (version 5.4; The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen) was used for data analysis. The pooled data showed that there was a non-significant reduction in the incidence of stroke and systemic embolism in the patients taking DOACs as compared to warfarin (HR 0.69; 95% CI, 0.29, 1.67; I² = 50%). The incidence of major bleeding was lower in the DOACs group; the difference was statistically significant (HR 0.42; 95% CI, 0.26, 0.67; I² = 7%). The difference was not statistically significant for all-cause mortality in both groups (HR 1.24; 95% CI, 0.91, 1.67; I² = 0%).

Conclusion

Our results showed that there was no difference in the outcomes of stroke and systemic embolism between DOACs and warfarin but there were statistically significantly lower major bleeding events. We conclude that larger clinical trials are needed to assess the true safety and efficacy of DOACs in patients with AF and bioprosthetic valves.

Dabigatran Versus Warfarin After Bioprosthesis Valve Replacement for the Management of Atrial Fibrillation Postoperatively: DAWA Pilot Study

Objectives

Dabigatran is a direct thrombin inhibitor shown to be an effective alternative to warfarin in patients with non-valvular atrial fibrillation (AF). We evaluated the use of dabigatran in patients with bioprosthetic mitral and/or aortic valve replacement and AF.

Methods

We selected 34 and randomized 27 patients in a 1:1 ratio to receive dabigatran or warfarin. The primary endpoint was the presence of a new intracardiac thrombus at 90 days, by transesophageal echocardiogram (TEE). Secondary endpoints included the development of dense spontaneous echo contrast (SEC) and incidence of stroke (ischemic or hemorrhagic), myocardium infarction, valve thrombosis and peripheral embolic events.

Results

The trial was terminated prematurely because of low enrollment. There were 27 patients in total: 15 patients placed in the dabigatran group and 12 in the warfarin group. After 90 days, one patient (8.3 %) in the warfarin group and none in the dabigatran group had developed a new intracardiac thrombus. In the dabigatran group, two patients (13.3 %) developed dense SEC versus one patient (8.3 %) in the warfarin group. In the warfarin group, one patient (8.3 %) presented ischemic stroke, and none did in the dabigatran group. We observed no cases of hemorrhagic stroke, valve thrombosis, embolic events or myocardial infarction in either group throughout the study. However, one patient (6.7 %) in the dabigatran group had a fully recovered transient ischemic attack and one patient in the warfarin group died of heart failure.

Conclusions

The use of dabigatran appears to be similar to warfarin in preventing the formation of intracardiac thrombus.

Trial Registration

Clinicaltrials.gov NCT01868243.