ABSTRACT
BACKGROUND : In transcatheter aortic valve implantation (TAVI) procedures, aortic valve annulus sizing is a key-step in deciding prosthesis size. The main complication post TAVI remains paravalvular aortic regurgitation (PVR). Survival after TAVI is highly correlated with the presence of moderate/severe PVR. One of the causes of aortic leak is an inadequate choice of valve size. Multi-detector row computed tomography (MDCT) is the first choice imaging method to calculate the annulus size. 3D transoesophageal echocardiography (TEE) is another emerging technique. As compared with 2D modalities, 3D modalities have been shown to be more accurate. However, 3D imaging modalities have so far rarely been compared.
AIM : We aim to compare measures of the aortic annulus by MDCT as compared to measures by 3D- TEE and evaluate the correlation between the imaging technique and the final annulus prosthesis size. Furthermore, we aim to investigate the correlation between the imaging technique chosen to decide the prosthesis size and the incidence of aortic regurgitation (AR) after TAVI.
METHODS : We established a cohort of patients who underwent TAVI between 2013 and 2016 in the Cardiology Department of the Lausanne University Hospital (CHUV).
We collected data in our defined cohort relating to each imaging techniques: Transthoracic echocardiography, MDCT, 2D-TEE and 3D-TEE.
We proceeded with a retrospective analysis of peri-procedural 3D-TEE data versus pre-procedural MDCT data and made comparisons with implanted prosthesis size.
RESULTS : Between 18.01.2013 and 14.09.2016, 199 patients underwent TAVI in our Department. Among them, results of MDCT were available in 165 patients whereas results of 3D-TEE were available in 106. As compared to MDCT, annulus size by 3D-TEE were significantly lower (22 [21;24.5]mm versus 24 [22;26]mm, p<0.001). Differences between implanted prosthesis size and the MDCT annulus size were significantly lower than those with 3D-TEE (1.5 [0;2.85]mm versus 3 [1.5;4.5]mm, p<0.001).
CONCLUSIONS : Annulus sizes assessed by 3D-TEE are significantly lower than annulus sizes assessed by MDCT. Operators should be aware of these differences and choose the annulus size consequently. Knowing these significant differences in prosthesis sizing between 3D-TEE and MDCT, TAVI can be performed without CT-scan and thus without contrast agent in population at risk of kidney failure. Other large prospective trials should investigate if the imaging modality choice could impact the occurrence of paravalvular leak after TAVI.