Multimodality assessment of high- vs. low-gradient aortic stenosis using echocardiography and cardiac CT.

Background: Aortic valve area (AVA) using CT-LVOT area (AVA _CT-LVOT ) <1.2 ​cm ² has been shown comparable to echocardiography AVA of <1.0 ​cm ² for severe aortic stenosis (AS). Current study evaluates how AS diagnosis will be affected when we substitute CT-LVOT with echo derived LVOT.
Methods: We retrospectively studied 367 patients who underwent cardiac CTA and echocardiogram for assessment of high- and low-gradient AS (HG-AS and LG-AS). AVA _CT-LVOT was derived from CT-LVOT area and echo doppler data. Three AVA _CT-LVOT categories were created (<1.0, 1.0-1.2 and ​> ​1.2 ​cm ² ). Outcomes were defined as composite of all-cause mortality and/or valve intervention.
Results: Median echocardiographic profiles were consistent with severe AS across three AVA _CT-LVOT categories for HG-AS. HG-AS patients with AVA _CT-LVOT >1.2 ​cm ² had larger median CT-LVOT area (5.06 ​cm ² ) and AVC (2917AU). Among LG-AS with AVA _CT-LVOT  ​≤1.2 cm ² , 57% met echo criteria for low-flow LG-AS and 63% met criteria for severe AS using aortic valve calcium (AVC). Additionally, 45% with AVA _CT-LVOT >1.2 ​cm ² had larger median CT-LVOT area (5.43 ​cm ² ) and AVC (2389AU). Patients with AVA _CT-LVOT >1.2 ​cm ² and high AVC had large body surface area and were mostly characterized as severe with indexed AVA and AVC. Stroke volume index using CT-LVOT reclassified 70% of low-flow, LG-AS as normal flow, LG-AS. Composite outcomes were higher among patients with AVA _CT-LVOT ≤1.2 ​cm ² (p ​< ​0.01), however, with no superior net reclassification improvement compared to AVA _echo <1.0 ​cm ² .
Conclusion: AVA _CT-LVOT ≤1.2 ​cm ² is a reasonable CT criterion for severe AS. Large LVOT with elevated AVC identified a severe AS phenotype despite an AVA _CT-LVOT >1.2 ​cm ² , best characterized by indexed AVA and AVC.
Competing Interests: Declaration of competing interest Dr. Philippe Pibarot has received funding from Edwards Lifesciences, Medtronic, Pi-Cardia, and Cardiac Phoenix for echocardiography core laboratory analyses and research studies in the field of transcatheter valve therapies, for which he received no personal compensation. He has received lecture fees from Edwards Lifesciences and Medtronic. Dr. Rebecca T. Hahn has received speaker fees from Abbott Structural, Baylis Medical, Edwards Lifesciences, and Philips Healthcare; has institutional consulting contracts for which she receives no direct compensation with Abbott Structural, Boston Scientific, Edwards Lifesciences, Medtronic, and Novartis; and has equity with Navigate. Dr. Jonathon Leipsic has held institutional research core lab agreements with Medtronic, Edwards Lifesciences, Abbott, Boston Scientific, and Pi-Cardia. Rest of the authors have conflict of interest to disclose.
(Copyright © 2023 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.)