Cardiac Magnetic Resonance Imaging Versus Computed Tomography to Guide Transcatheter Aortic Valve Replacement: A Randomized, Open-Label, Noninferiority Trial

Abstract

Background: Computed tomography (CT) is recommended for guiding transcatheter aortic valve replacement (TAVR). However, a sizable proportion of TAVR candidates have chronic kidney disease, in whom the use of iodinated contrast media is a limitation. Cardiac magnetic resonance imaging (CMR) is a promising alternative, but randomized data comparing the effectiveness of CMR-guided versus CT-guided TAVR are lacking.

Methods: An investigator-initiated, prospective, randomized, open-label, noninferiority trial was conducted at 2 Austrian heart centers. Patients evaluated for TAVR according to the inclusion criteria (severe symptomatic aortic stenosis) and exclusion criteria (contraindication to CMR, CT, or TAVR, a life expectancy <1 year, or chronic kidney disease level 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. Noninferiority was assessed using a hybrid modified intention-to-treat/per-protocol approach on the basis of 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 (modified intention-to-treat cohort). Of these 267, 19 patients had protocol deviations, resulting in a per-protocol cohort of 248 patients (121 CMR-guided, 127 CT-guided). In the modified intention-to-treat 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% CI, -2.7% to 8.2%]; P<0.01 for noninferiority). In the per-protocol cohort (n=248), the between-group difference was 2.0% (90% CI, -3.8% to 7.8%; P<0.01 for noninferiority).

Conclusions: CMR-guided TAVR was noninferior to CT-guided TAVR in terms of device implantation success. CMR can therefore be considered as an alternative for TAVR planning.

Registration: URL: https://www.

Clinicaltrials: gov; Unique identifier: NCT03831087.

Keywords: computed tomography; magnetic resonance imaging; transcatheter aortic valve replacement.