Anticoagulation vs. Antiplatelet Therapy After TAVR
Is there an advantage to the use of a vitamin K antagonist (VKA) compared to antiplatelet therapy after bioprosthetic valve replacement?
Five databases were searched including PubMed, Medline, Embase, Ovid, and Cochrane for randomized clinical trials and observational studies comparing VKA versus antiplatelet or no therapy. Outcome was after surgical intervention. Mantel-Haenszel odds ratio (OR) was calculated using random-effects meta-analysis for the outcome. Heterogeneity was assessed by I2 statistics. A total of 14 studies were included (two randomized trials, 12 observational studies, and one conference abstract; total 31,740 patients).
There were no differences between groups in thromboembolic events (145 [1%] vs. 262 [1.5%]; OR, 0.96; 95% confidence interval [CI], 0.60-1.52), all-cause mortality (351 [3.5%] vs. 415 [2.9%]; OR, 1.48; 95% CI, 0.87-2.50), or need for redo surgery (47 [3.3%] vs. 55 [3.2%]; OR, 0.81; 95% CI, 0.42-1.58). However, there were more bleeding events in patients treated with a VKA compared to antiplatelet therapy (292 [2.6%] vs. 189 [1.1%]; OR, 2.26; 95% CI, 1.67-3.05).
In a meta-analysis of randomized and observational studies of VKA versus antiplatelet therapy or no treatment in patients undergoing bioprosthetic valve implantation, there was no benefit of adding a VKA regarding thromboembolism or mortality. However, use of a VKA was associated with increased risk of major bleeding.
The 2014 American Heart Association/American College of Cardiology Guideline for the Management of Patients With Valvular Heart Disease includes a Class IIa recommendation for the use of a VKA for 3 months after bioprosthetic mitral valve replacement, but a Class IIb recommendation for VKA therapy for 3 months after aortic valve replacement (AVR). Recent studies (predominantly driven by obligate imaging studies in randomized controlled trials after transcatheter [TAVR] vs. surgical AVR [SAVR]) have raised a question as to whether leaflet immobility and high gradients after TAVR or SAVR might be due to thrombus formation, and whether VKA therapy should be considered early after either. Although the present study suggests that there is no advantage to the broader use of a VKA after bioprosthetic valve replacement in general, it is a mixed study of aortic and mitral bioprosthesis in randomized and observational studies with various follow-up duration and endpoints, and probably does not provide a definitive answer to the question.
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