CMR-Guided TAVR Noninferior to CT-Guided TAVR for Device Implantation Success

Cardiac magnetic resonance (CMR)-guided transcatheter aortic valve replacement (TAVR) is noninferior to computed tomography (CT)-guided TAVR for device implantation success, researchers reported in Circulation.

The randomized, open-label, noninferiority TAVR-CMR (Cardiac Magnetic Resonance Imaging Versus Computed Tomography to Guide Transcatheter Aortic Valve Replacement; ClinicalTrials.gov Identifier: NCT03831087) trial was conducted at 2 heart centers in Austria and assessed the noninferiority of CMR vs CT for guiding TAVR.

Potential TAVR candidates were randomly assigned in a 1:1 fashion to have a predefined TAVR-CMR protocol or a standard contrast-enhanced TAVR-CT protocol to evaluate anatomic characteristics of the aortic annulus and access route. Eligible participants had severe aortic stenosis diagnosed based on guidelines of the European Society of Cardiology/European Association for Cardiothoracic Surgery and had typical symptoms of severe aortic stenosis.

The primary outcome was defined per the Valve Academic Research Consortium (VARC)-2 criteria as device success at discharge including absence of procedural mortality, correct positioning of a single prosthetic heart valve into the proper anatomic location, and proper intended performance of the prosthetic heart valve.

A total of 380 potential TAVR candidates were randomly assigned to CMR-guided (191 patients) or CT-guided (189 patients) TAVR planning from September 11, 2017, to December 16, 2022. Among the cohort, 138 participants in the CMR-guided group and 129 patients in the CT-guided group had TAVR (modified intention-to-treat [mITT] population). The per-protocol cohort included 248 patients (121 in the CMR group, 127 in the CT group). The median age for both populations was 82 years, and 50% were women.

For the mITT cohort, device implantation success occurred in 93.5% of patients in the CMR group and in 90.7% of patients in the CT group (between-group difference, 2.8%; 90% CI, -2.7 to 8.2%; P <.01 for noninferiority). In the per-protocol cohort, device implantation success occurred in 92.6% of the CMR-guided patients and in 90.6% of the CT-guided patients (between-group difference, 2.0%; 90% CI, -3.8 to 7.8%; P <.01 for noninferiority).

Stroke or transient ischemic attack (TIA) and the need for permanent pacemaker implantation occurred more frequently in the CT-guided group (stroke/TIA: 5.4% vs 0.7%; P =.02 in the mITT population; 5.5% vs 0.8%; P =.04 in the per-protocol population; permanent pacemaker: 11.6% vs 3.6%; P =.01; 11.8% vs 3.3%; P =.01, respectively).

The CMR and CT groups had comparable all-cause mortality at a median of 6 months (8.7% vs 7.0%, respectively; P =.60 in the mITT population; 8.3% vs 7.1%, respectively; P =.73 in the per-protocol population).

Sensitivity analyses with use of VARC-3 device success criteria were consistent with the primary outcome (mITT: 88.4% vs 85.3%; P =.01 for noninferiority; per-protocol: 90.1% vs 85.0%; P <.01 for noninferiority).

Among several limitations, the prespecified noninferiority margin of 9% absolute risk difference is liberal for an expected failure rate of 8%, the investigators noted. Also, the use of an alpha of 0.10 instead of 0.05 for nominal significance is different from convention. Other limitations included the open-label design, and contrast volume was not systematically evaluated.

“…CMR-guided TAVR was noninferior to CT-guided TAVR in terms of device implantation success at hospital discharge, with no difference between the groups in the proportion undergoing the TAVR procedure,” the study authors wrote.

This article originally appeared on The Cardiology Advisor