Computed tomography–based sizing recommendations for transcatheter aortic valve replacement with balloon-expandable valves: Comparison with transesophageal echocardiography and rationale for implementation in a prospective trial

BackgroundComputed tomography (CT) annular measurements are predictive of paravalvular regurgitation after transcatheter aortic valve replacement (TAVR) which is a predictor of mortality and morbidity.ObjectivesTo demonstrate the rationale and potential implications of new CT sizing recommendations for TAVR.MethodsThe CT sizing recommendations aim to ensure routine transcatheter heart valve (THV) oversizing of the aortic annular area [(THV external area/systolic annular area − 1) × 100; range, 1%–20%; target, 10%–15%]. Consecutive patients (n = 120) underwent CT before TAVR with balloon-expandable valves sized by transesophageal echocardiography (TEE). Retrospectively, the CT-recommended THV size was compared with the actual size implanted.ResultsCompared with TEE, application of the newly developed CT-based sizing recommendations would have led to implantation of a larger valve in 33.3% (40/120), no change in valve size in 55.8% (67/120), and a smaller valve in 10.8% (13/120). In patients when CT recommended a larger valve, the incidence of at least moderate paravalvular regurgitation was 25% (10/40) compared with 4.5% (3/67; P < 0.01) when both TEE and CT recommendations were in agreement. Using diastolic versus systolic CT measurements results in 20% of patients receiving smaller THVs. TEE sizing resulted in 33.3% (40/120) of valves being undersized (THV area < CT systolic annular area) with a mean annular oversizing of 9.4% ± 17.4% (range: −21.5% to 65.9%) without annular rupture. In contrast, the CT sizing recommendations results in mean annular oversizing of 13.9% ± 8.0% (range, 1.3%–29.8%).ConclusionThese CT sizing recommendations enable standardized moderate overexpansion of the aortic annulus. Clinical outcomes from these recommendations are being prospectively assessed in a multicenter trial.