The risk of valve thrombosis is higher with intra-annular versus supra-annular transcatheter aortic valve prosthesis. A meta-analysis from randomized controlled trials

Abstract

Valve thrombosis (VT) after transcatheter aortic valve implantation (TAVI) may be associated with heart failure and thromboembolic events. Its reported incidence ranges from 0.6 to 2.8%, depending on the definition, the diagnostic imaging modality and the type of patients evaluated [1]. The pathogenesis of VT after TAVI is mainly related to alterations in blood flow, and because of that it is more frequent after valve-in-valve procedures, in presence of patient-prosthesis mismatch, or when cardiac output is reduced [1]; all of these situations being associated with more stagnant blood flow. The implantation of intra-annular (IAV) in comparison with supra-annular (SAV) transcatheter aortic heart valves has been associated with a higher risk of leaflet thrombosis in observational studies [2]. To clarify whether the risk of VT is higher with IAV in comparison with SAV, we performed a meta-analysis including five randomized trials comparing both device types. We identified five randomized trials comparing IAV and SAV: CHOICE [3], ELECT [4], REPRISE-III [5], SCOPE-I [6] and SOLVE-TAVI [7]. Three studies compared Edwards Lifesiences (Irvine, CA) with Medtronic Inc. (Minneapolis, MN) devices (CHOICE, ELECT, and SOLVE-TAVI), the REPRISE-III compared Lotus (Boston Scientific, Marlborough, MA) and Corevalve valves, and the SCOPE-I compared the Edwards device with Acurate Neo valve (Boston Scientific). Other randomized studies were not included because compared two SAV (SCOPE-II) or one IAV with no specific valve (PORTICO-IDE). We compared between both groups the incidence of VT (ARC-2 criteria), as well as stroke, cardiovascular mortality and overall mortality. For each study, the longest follow-up available was considered (1 year for ELECT, SCOPE-I, and SOLVE-TAVI, 2 years for REPRISE-III, and 5 years for the CHOICE study). The meta-analysis was conducted according to the Quality of Reports of Meta-Analyses of Randomized Clinical Trials (QUOROM) recommendations. Reviewer Manager 5.4 (Cochrane Collaboration, Oxford, UK) was used. No significant differences were found between both groups regarding factors related to thrombotic risk (e.g., atrial fibrillation) or anti-thrombotic therapy. The incidence of VT was significantly lower in SAV in comparison with IAV (0.1 vs. 1.2%, p = 0.003), whereas no significant differences were found in the rates of all-cause mortality (18.2 vs. 18.7%, p = 0.93), cardiovascular death (9.8 vs. 10.4%, p = 0.82) or stroke (7.3 vs. 7.4%, p = 0.76) (Fig. 1). IAV create larger neo-sinuses and stagnation zones [8] and may have more under-expansion and non-circular shape at the leaflet level, and, all of these may favor local thrombogenicity. The lower risk of VT of SAV could be related to the porcine vs bovine pericardium, but no differences or even higher risk of thrombosis were found with porcine valves [9]. The main limitation of our study is that the trials included did not examine VT systematically via trans-esophageal echocardiography or computed tomography. Because of that, the incidence of VT may have been underestimated. In the study by Rashid, that included only observational studies, but with computed tomography evaluation, the incidence of VT was 13.7 and 7.0% for IAV and SAV devices, respectively [2]. * Raúl Moreno [email protected]