Meta-analysis on the comparison of direct oral anticoagulants versus vitamin K antagonists after transcatheter aortic valve implantation in patients with pre-existing atrial fibrillation
Authors: Mateo Q , Tiongco R , Bernardo J 
Published: October 2022

Abstract

Background
Transcatheter aortic valve replacement is a treatment option for symptomatic patients with severe aortic stenosis who are candidates for a bioprosthesis across the entire spectrum of risk. TAVR carries a risk for thrombotic and bleeding events, underscoring the importance of defining the optimal adjuvant antithrombotic regimen. Antithrombotic consideration is complicated by the fact that many patients undergoing TAVR are generally elderly with multiple comorbidities, including conditions that may require long-term oral anticoagulation such as atrial fibrillation. The optimal antithrombotic regimen for patients with AF undergoing TAVR is currently unknown. The objective of this meta-analysis is to add knowledge to existing data involving the use of direct oral anticoagulant in patients with pre-existing atrial fibrillation undergoing TAVI and to explore the safety and efficacy of DOACs compared with VKA in this population

Methods
A systematic search for randomized controlled trials which compare direct oral anticoagulant and vitamin K antagonist was done using PubMed, Cochrane, MEDLINE and Clinicaltrials.gov. Studies which were done in the last five years (January 2016-October 2021) and those that involved human subjects were included in the study. Search terms include “Direct Oral Anticoagulant”, “Vitamin K Antagonist”, “TAVR”, “atrial fibrillation”, “DOAC” AND “TAVI” OR “VKA” AND “TAVI” AND “atrial fibrillation” AND “randomized controlled trial”.

Results
Five retrospective observational studies and two RCTs (3,998) were included in this meta-analysis comparing direct oral anticoagulant vs vitamin K antagonist in patients with known atrial fibrillation post TAVI. Dabigatran, Rivaroxaban, Apixaban, and Edoxaban were used in these different studies. Among patients with concomitant indication of oral anticoagulant like atrial fibrillation, there is no significant difference between direct oral anticoagulant and vitamin K antagonist in terms of outcomes on all-cause mortality, major and/or life threatening bleeding and stroke as shown in these values, (OR 1.05, 95% CI: 0.89–1.25, P=0.57, I2=39%), (OR=1.04, 95% CI: 0.85–1.27, P=0.70, I2=45%) and (OR=1.10, 95% CI: 0.80–1.51, p=0.56, I2=0%), respectively. When only the two RCTs are compared, still there is no significant difference on the outcomes mentioned above between direct oral anticoagulant and vitamin K antagonist based on these values (OR=1.07, 95% CI: 0.85–1.36, P=0.57, I2=0%), (OR=1.15, 95% CI: 0.59–2.24, P=0.68, I2=66%) and (OR=0.99, 95% CI: 0.65–1.49, p=0.95, I2=39%), respectively.

Conclusion
Use of direct oral anticoagulant was non inferior with vitamin K antagonist in terms of outcomes on all-cause mortality, major and/or life threatening bleeding and stroke. Direct oral anticoagulant is easier to use with its known safety profile, hence, it is a plausible alternative to warfarin in this population in patients with known atrial fibrillation post TAVR.

Funding Acknowledgement
Type of funding sources: Private hospital(s). Main funding source(s): St. Luke's Medical Center Taguig City