Comparison Between Gated Cardiac Magnetic Resonance Angiography and Computed Tomography Angiography for Harmony Valve Anatomic Fit Analysis.

Aims: To determine if electrocardiogram (ECG)-gated magnetic resonance angiography (MRA) can be used to assess candidacy for transcatheter pulmonary valve replacement with the Harmony valve.

Background: Anatomic fit assessment for the Harmony valve is conducted with retrospectively gated computed tomography angiography (CTA). The suitability of MRA for this purpose has not been assessed.

Methods: We analyzed patients who were screened for Harmony valve candidacy at our institution through July 2024 and had both ECG-gated MRA and CTA. Measurements included RVOT centerline length and RVOT perimeters and diameters at 5 mm increments. The Medtronic fit algorithm was applied to CTA and MRA measurements. Correlation between CTA and MRA measurements was determined with intraclass correlation coefficient (ICC) and Bland-Altman analysis.

Results: The study included 36 patients who met the inclusion criteria. The ICC between CTA and MRA was 0.99 for RVOT length, 0.92 for minimum perimeter-derived diameter, and 0.71 for proximal perimeter-derived diameter (all p < 0.001). MRA fit analysis was concordant with the Medtronic CTA-derived fit analysis in 72% of patients and was concordant with fit analysis based on internal CTA measurements in 75%.

Conclusion: RVOT measurements on ECG-gated MRA images correlate well with those made from retrospectively gated CTA. Although perimeter plots generated from ECG-gated MRA and CTA measurements were discordant in some patients, the differences were minor and could still be interpreted to indicate implantable anatomy by the operator. These findings suggest that ECG-gated MRA may be an acceptable surrogate for CTA during the anatomic screening process.