Cardiac Magnetic Resonance Imaging Versus Computed Tomography to Guide Transcatheter Aortic Valve Replacement (TAVR-CMR): A Randomized, Open-Label, Non-Inferiority Trial.

Background: Computed tomography (CT) is recommended for guiding transcatheter aortic valve replacement (TAVR). However, as a sizable proportion of TAVR candidates have chronic kidney disease (CKD), the use of iodinated contrast media is a limitation. Cardiac magnetic resonance (CMR) is a promising alternative, yet randomized data comparing the effectiveness of CMR- versus CT-guided TAVR are lacking. Methods: An investigator-initiated, prospective, randomized, open-label, non-inferiority trial was conducted at two Austrian heart centers. Patients evaluated for TAVR according to the inclusion (severe symptomatic aortic stenosis) and exclusion criteria (contraindication to CMR, CT, or TAVR, a life expectancy < 1 year, CKD 4 or 5) were randomized (1:1) to undergo CMR- or CT-guiding. The primary outcome was defined according to the Valve Academic Research Consortium-2 definition of implantation success at discharge, including absence of procedural mortality, correct positioning of a single prosthetic valve, and proper prosthetic valve performance. Non-inferiority was assessed using a hybrid modified intention-to-treat (mITT)/per-protocol (PP) approach based on an absolute risk difference margin of 9%. Results: Between September 11, 2017, and December 16, 2022, 380 candidates for TAVR were randomized to CMR-guided (191 patients) or CT-guided (189 patients) TAVR planning. Of these, 138 patients (72.3%) in the CMR-guided group and 129 patients (68.3%) in the CT-guided group eventually underwent TAVR (mITT cohort). Of these 267, 19 patients had protocol deviations, resulting in a PP cohort of 248 patients (n=121 CMR-guided, n=127 CT-guided). In the mITT cohort, implantation success was achieved in 129 patients (93.5%) in the CMR group and in 117 patients (90.7%) in the CT group (between-group difference, 2.8%; 90% confidence interval [CI]: -2.7 to 8.2%; p<0.01 for non-inferiority). In the PP cohort (n=248), the between-group difference was 2.0% (90% CI: -3.8 to 7.8%; p<0.01 for non-inferiority). Conclusions: CMR-guided TAVR was non-inferior to CT-guided TAVR in terms of device implantation success. CMR can therefore be considered as an alternative for TAVR planning.