Non-Contrast Enhanced MR Angiography in Pre-Procedural Assessment of Aortic Annulus for Transcatheter Aortic Valve Replacement.

The purpose of this retrospective study is to investigate the feasibility of measurement of aortic annular size using a respiratory and non-contrast magnetic resonance angiography (MRA) in comparison to those of computed tomography angiography (CTA) in an unselected, consecutive cohort of patients evaluated for transcatheter aortic valve replacement (TAVR). Of 295 consecutive patients (mean age 83.0 ± 4.5 years) with severe aortic stenosis, 68 underwent pre-TAVR CTA and a non-contrast balanced steady-state free precession MRA at 1.5 T. This study evaluated potential discrepancies in preoperative assessments of TAVR device size selection determined by CTA and MRA, and compared with paravalvular aortic valve regurgitation (PAR). The aortic annulus area (AAA) and perimeter (AAP) measured with systolic MRA showed a higher correlation to systolic CTA than those measured with diastolic MRA: intraclass correlation coefficient (ICC) with 95% concordance index (CI) of measured AAA between systolic CTA vs. systolic and diastolic MRA, 0.891 (CI 0.830-0.932) and 0.833 (CI 0.742-0.893), respectively; ICC with 95% CI of measured AVP between systolic CTA vs. systolic and diastolic MRA, 0.892 (CI 0.831-0.932) and 0.841 (CI 0.754-0.899). Of the 68 patients, 52 assigned the same device size, 2 assigned an oversized device, and 14 assigned undersized devices when sizing was based on systolic MRA as compared to systolic CTA. Virtual MRA-sizing assigned under-sizing for 14 patients, 9 of whom presented PAR grade 1 by CTA-sizing. This under-sizing could potentially increase the severity of PAR postoperatively, with the possibility of escalating PAR to grade 2 or above.