Erroneous 2-D TEE Measurements Result in Inappropriate Sizing for CoreValve

June 17, 2014—A retrospective comparison using multislice computed tomography (CT) showed that erroneous measurement of the aortic annular diameter using two-dimensional echocardiography resulted in inappropriate size selection for with the Medtronic, Inc. CoreValve transcatheter heart valve (THV) system. Darren Mylotte, MD, et al published the study in the Journal of the American College of Cardiology (JACC): Cardiovascular Interventions (2014;7:652–661).

The study sought to assess the differential adherence to THV-oversizing principles between transesophageal echocardiography (TEE) and multislice CT and its impact on the incidence of paravalvular leak (PVL). CT has emerged as an alternative to 2-dimensional TEE for THV sizing, noted the investigators.

The investigators stated that in their early experience of Core Valve procedures, TEE-derived aortic annular diameters determined THV size selection. CT datasets originally obtained for vascular screening were retrospectively interrogated to determine CT-derived annular diameters. Annular dimensions and expected THV oversizing were compared between TEE and CT. The incidence of PVL was correlated to TEE- and CT-based oversizing calculations.

As summarized in JACC: Cardiovascular Interventions, 157 patients underwent CoreValve implantation (23 mm: n = 66; 29 mm: n = 91) using TEE-derived annulus measurements, The estimated THV oversizing on the basis of TEE was 20.1 ± 8.2%. Retrospective CT analysis yielded larger annular diameters than TEE (P < .0001). When these CT diameters were used to recalculate the percentage of oversizing achieved with the TEE-selected CoreValve, the actual THV oversizing was only 10.4 ± 7.8%. Consequently, CT analysis suggested that up to 50% of patientsreceived an inappropriate CoreValve size.

When CT-based sizing criteria were satisfied, the incidence of PVL was 21% lower than that with echocardiography (14% vs 35%; P = .003). Adherence to CT-based oversizing was independently associated with a reduced incidence of PVL (odds ratio 0.36; 95% confidence interval: 0.14 to 0.9; P = .029); adherence to TEE-based sizing was not.

This retrospective CT-based annular analysis revealed that CoreValve size selection by TEE was incorrect in 50% of patients, and the percentage of oversizing with CT was one-half of that calculated with TEE resulting in the majority of patients receiving a THV that was too small, concluded the investigators in JACC: Cardiovascular Interventions.