Maximum Aortic Valve Opening Phase for Annulus Sizing in Pre-TAVR CTA.

Area of Science:

• Cardiovascular Imaging
• Interventional Cardiology
• Cardiac Anatomy

Background:

• Standardization of the optimal phase for aortic annular area measurement in transcatheter aortic valve replacement (TAVR) is lacking.
• Current practice often favors systolic measurements, assuming the annulus is largest during this phase.

Purpose of the Study:

• To test the hypothesis that the maximum aortic annular area occurs at the cardiac phase of maximum aortic valve opening (MAVO).
• To determine if MAVO can be accurately and reproducibly assessed by visual inspection alone for TAVR planning.

Main Methods:

• Visual inspection by two readers to identify the MAVO phase.
• Measurement of annular area at both MAVO and a typical systolic phase (35% R-R interval).
• Analysis of differences in annular area and their impact on prosthesis sizing.

Main Results:

• MAVO occurred between 15%-25% of the R-R interval in 90% of patients.
• High interobserver correlation (0.89) for visual MAVO determination.
• Maximal annular area was observed at MAVO in 49 out of 50 patients, with a mean difference of 22.3 mm² compared to the 35% phase.
• Significant implications for prosthesis sizing in 12% (self-expanding) and 32% (balloon-expandable) of cases.

Conclusions:

• Visually assessed MAVO, occurring in early systole, consistently represents the phase of maximal aortic annular area.
• This visual method offers a rapid and reproducible approach for TAVR planning measurements.
• Optimizing CT acquisitions for early systolic reconstruction is recommended for MAVO determination.