There could be a new gold standard for aortic annular evaluation before transcatheter aortic valve replacement (TAVR) as 3D CT imaging has been shown to be superior to 2D transesophageal echocardiography (TEE), according to a study published Feb. 22 online in the Journal of the American College of Cardiology .
“There is a growing appreciation that [2D] echocardiography fails to appreciate the noncircular geometry of the aortic annulus and that [CT], as a 3D assessment, appears superior in this respect,” wrote Raj R. Makkar, MD, of Cedars-Sinai Heart Institute in Los Angeles, and colleagues.
To evaluate the different modalities, the authors conducted a retrospective study of patients scheduled for TAVR between January 2008 and March 2011, to analyze CT dimensions in patients who had also undergone TEE-guided TAVR in order to compare the predictive value of measures of the aortic annulus for post-TAVR paravalvular (PV) aortic regurgitation (AR). They also assessed the impact of a prospective application of CT annular measurements in choosing bioprosthesis size.
Of the 192 patients scheduled for TAVR with the Edwards Lifesciences Sapien valve during the study period, 81 received ECG-gated contrast thoracic scans and a randomly selected subset of 20 patients was compared in systole and diastole.
Results of the retrospective analysis showed that CT imaging would have reassigned 45 percent of patients who underwent TEE to a different size Sapien valve. Twenty-six of the 60 patients who received a 23 mm valve would have been switched to a 26 mm valve and 17 of 36 would have had annuli deemed too large for a 26 mm bioprosthesis, according to the authors.
CT-guided annular sizing also resulted in improved outcomes, with only two out of a subset of 40 patients experiencing moderate paravalvular aortic regurgitation following the procedure.
“The minimization of PV regurgitation is critical before TAVR can be applied to low surgical-risk populations,” wrote Makkar et al. “Our data lend strong support to 3D cross-sectional measures, using CT as the new gold standard for aortic annular evaluation for TAVR with the Edwards Sapien device.”
The authors noted the study was limited because the results with other valve types are unproven and other imaging techniques, such as 3D TEE, could overcome some of the problems of conventional 2D TEE.
Makkar and colleagues also suggested that enhanced aortic annular sizing will lead to the creation of more valve sizes that could further improve outcomes.