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Association of Myocardial Fibrosis and Stroke Volume by Cardiovascular Magnetic Resonance in Patients With Severe Aortic Stenosis With Outcome After Valve Replacement. The British Society of Cardiovascular Magnetic Resonance AS700 Study

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posted on 2024-05-10, 15:09 authored by George D Thornton, Tarique A Musa, Marzia Rigolli, Margaret Loudon, Calvin Chin, Silvia Pica, Tamir Malley, James RJ Foley, Vassilios S Vassiliou, Rhodri H Davies, Gabriella Captur, Laura E Dobson, James C Moon, Marc R Dweck, Saul G Myerson, Sanjay K Prasad, John P Greenwood, Gerry P McCann, Anvesha Singh, Thomas A Treibel

Importance

Low-flow severe aortic stenosis (AS) has higher mortality than severe AS with normal flow. The conventional definition of low-flow AS is an indexed stroke volume (SVi) by echocardiography less than 35 mL/m2. Cardiovascular magnetic resonance (CMR) is the reference standard for quantifying left ventricular volumes and function from which SVi by CMR can be derived.

Objective

To determine the association of left ventricular SVi by CMR with myocardial remodeling and survival among patients with severe AS after valve replacement.

Design, setting, and participants

This multicenter longitudinal cohort study was conducted between January 2003 and May 2015 across 6 UK cardiothoracic centers. Patients with severe AS listed for either surgical aortic valve replacement (SAVR) or transcatheter aortic valve replacement (TAVR) were included. Patients underwent preprocedural echocardiography and CMR. Patients were stratified by echocardiography-derived aortic valve mean and/or peak gradient and SVi by CMR into 4 AS endotypes: low-flow, low-gradient AS; low-flow, high-gradient AS; normal-flow, low-gradient AS; and normal-flow, high-gradient AS. Patients were observed for a median of 3.6 years. Data were analyzed from September to November 2021.

Exposures

SAVR or TAVR.

Main outcomes and measures

All-cause and cardiovascular (CV) mortality after aortic valve intervention.

Results

Of 674 included patients, 425 (63.1%) were male, and the median (IQR) age was 75 (66-80) years. The median (IQR) aortic valve area index was 0.4 (0.3-0.4) cm2/m2. Patients with low-flow AS endotypes (low gradient and high gradient) had lower left ventricular ejection fraction, mass, and wall thickness and increased all-cause and CV mortality than patients with normal-flow AS (all-cause mortality: hazard ratio [HR], 2.08; 95% CI, 1.37-3.14; P < .001; CV mortality: HR, 3.06; 95% CI, 1.79-5.25; P < .001). CV mortality was independently associated with lower SVi (HR, 1.64; 95% CI, 1.08-2.50; P = .04), age (HR, 2.54; 95% CI, 1.29-5.01; P = .001), and higher quantity of late gadolinium enhancement (HR, 2.93; 95% CI, 1.68-5.09; P < .001). CV mortality hazard increased more rapidly in those with an SVI less than 45 mL/m2. SVi by CMR was independently associated with age, atrial fibrillation, focal scar (by late gadolinium enhancement), and parameters of cardiac remodeling (left ventricular mass and left atrial volume).

Conclusions and relevance

In this cohort study, SVi by CMR was associated with CV mortality after aortic valve replacement, independent of age, focal scar, and ejection fraction. The unique capability of CMR to quantify myocardial scar, combined with other prognostically important imaging biomarkers, such as SVi by CMR, may enable comprehensive stratification of postoperative risk in patients with severe symptomatic AS.

Funding

Cardiovascular MR evaluation of the safety and efficacy of Transcatheter Aortic Valve Implantation (TAVI) compared to surgical Aortic Valve Replacement (AVR)

British Heart Foundation

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Contribution of LVH and diastolic dysfunction assessed by myocardial tissue tagging to symptoms and exercise intolerance in severe aortic stenosis

British Heart Foundation

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University of Oxford, grant FS/10/015/28104

University of Edinburgh, grant FS/10/026

University College London, grants FS/08/028/24767 [Dr Moon], FS/19/35/34374 [Dr Treibel], and FS/CRTF/21/24128 [Dr Thornton])

UK National Institute for Health Research via its Biomedical Research Centre and Clinical Research Facility (Leeds and Oxford) programmes

Rosetrees Trust.

History

Author affiliation

College of Life Sciences/Cardiovascular Sciences

Published in

JAMA Cardiology

Volume

7

Issue

5

Pagination

513 - 520

Publisher

American Medical Association

issn

2380-6583

eissn

2380-6591

Copyright date

2022

Available date

2024-05-10

Spatial coverage

United States

Language

English

Deposited by

Dr Anvesha Singh

Deposit date

2024-05-09

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