Non-Contrast Cardiovascular Magnetic Resonance for Aortic Valve Annulus Measurement in TAVI Planning: Correlation with Implanted Endoprosthesis

Background: Computed tomography angiography is the gold standard for measuring the subvalvular aortic annulus in TAVI planning. However, iodinated contrast poses risks in renal dysfunction. Non-contrast cardiac magnetic resonance (CMR) can yield accurate annular and adjacent structure measurements without intravenous agents.

Methods: We retrospectively reviewed 14 consecutive patients (2017–2025) who underwent non-contrast CMR before TAVI. ECG-synchronized SSFP images were used for annular planimetry (area, perimeter, orthogonal diameters), left ventricular outflow tract assessment, sinus of Valsalva evaluation, coronary ostial height measurement, and sinotubular junction analysis. For balloon-expandable valves (Sapien), sizing followed annular area criteria: 23 mm (≤410 mm²), 26 mm (≤480 mm²), or 29 mm ( >480 mm²). For self-expanding valves (CoreValve/Evolut/Navitor), sizing was based on annular perimeter per manufacturer guidelines. In borderline cases, oversizing or undersizing was allowed if supported by intraoperative transesophageal echocardiography and minimal contrast use. The primary endpoint was concordance between CMR recommendations and the implanted valve. Complications and technical success were assessed per VARC-3 criteria.

Results: All measurements were completed without contrast. CMR recommendations matched the implanted device in 9 of 14 patients (64.3%): 7 of 10 balloon-expandable and 2 of 4 self-expanding valves. Discordances (5 cases) arose from annular ovalization extremes, borderline sizing, and intraoperative adjustments guided by echocardiography and minimal contrast. No perioperative, early, or late complications occurred according to VARC-3 standards.

Conclusion: Non-contrast CMR reliably measured the aortic annulus and related structures, with concordance rates comparable to existing literature. Discordances reflected individualized operator decisions rather than imaging limitations. These findings endorse contrast-free CMR as a viable alternative for TAVI planning in patients with contraindications to iodinated contrast, enhancing procedural safety in those with renal impairment.This investigation demonstrates the clinical feasibility and diagnostic accuracy of non-contrast cardiovascular magnetic resonance imaging as a sophisticated alternative to conventional contrast-enhanced computed tomography for transcatheter aortic valve replacement planning, particularly valuable in the challenging clinical scenario of severe renal dysfunction where contrast avoidance is paramount for optimal patient outcomes.