A revised methodology for aortic-valvar complex calcium quantification for transcatheter aortic valve implantation

Area of Science:

• Cardiovascular Imaging
• Interventional Cardiology
• Medical Physics

Background:

• Severe symptomatic aortic stenosis necessitates transcatheter aortic valve implantation (TAVI).
• Paravalvular leak (PVL) is a significant complication following TAVI.
• Accurate prediction of PVL is crucial for optimal patient outcomes.

Purpose of the Study:

• To optimize a computed tomography (CT) method for quantifying aortic-valvar complex calcium.
• To predict significant paravalvular leak (PVL) after transcatheter aortic valve implantation (TAVI).

Main Methods:

• Utilized contrast-enhanced CT data from 198 patients undergoing balloon-expandable TAVI.
• Quantified paravalvular leak (PVL) using peri-procedural transesophageal echocardiography (TEE) per Valve Academic Research Consortium-2 (VARC-2) criteria.
• Developed a region-of-interest methodology to differentiate leaflet and left ventricular outflow tract (LVOT) calcium, analyzing predictive values at different Hounsfield Unit (HU) thresholds.

Main Results:

• Optimal CT thresholds for PVL prediction were 450 HU (≥626 mm³) for non-contrast scans and 850 HU (≥235 mm³) for contrast scans.
• Left ventricular outflow tract (LVOT) calcium predicted PVL as a binary variable.
• Multivariable analysis identified annulus area ≥ prosthesis area, contrast leaflet calcium volume (850 HU threshold), and LVOT calcium presence as independent predictors of moderate or severe PVL.

Conclusions:

• Both leaflet and LVOT calcium are significant, synergistic predictors of PVL after TAVI, even with appropriately sized valves.
• Clinically relevant leaflet calcium volumes can be identified using either non-contrast or contrast CT scans with appropriate Hounsfield Unit (HU) threshold selection.