12 Jul 21. Featured Paper

First-phase ejection fraction by cardiovascular magnetic resonance predicts outcomes in aortic stenosis.

Link to paper on Journal of Cardiovascular Magnetic Resonance

Authors

Haotian Gu, Rong Bing, Calvin Chin, Lingyun Fang, Audrey C. White, Russell Everett, Nick Spath, Eunsoo Park, John B. Chambers, David E. Newby, Amedeo Chiribiri, Marc R. Dweck & Phil Chowienczyk

Abstract

Background: First-phase ejection fraction (EF1; the ejection fraction measured during active systole up to the time of maximal aortic flow) measured by transthoracic echocardiography (TTE) is a powerful predictor of outcomes in patients with aortic stenosis.

We aimed to assess whether cardiovascular magnetic resonance (CMR) might provide more precise measurements of EF1 than TTE & to examine the correlation of CMR EF1 with measures of fibrosis.

Methods: In 141 patients with at least mild aortic stenosis, we measured CMR EF1 from a short-axis 3D stack & compared its variability with TTE EF1, & its associations with myocardial fibrosis & clinical outcome (aortic valve replacement (AVR) or death).

Results: Intra- & inter-observer variation of CMR EF1 (standard deviations of differences within & between observers of 2.3% & 2.5% units respectively) was approximately 50% that of TTE EF1.

CMR EF1 was strongly predictive of AVR or death.

On multivariable Cox proportional hazards analysis, the hazard ratio for CMR EF1 was 0.93 (95% confidence interval 0.89–0.97, p = 0.001) per % change in EF1 &, apart from aortic valve gradient, CMR EF1 was the only imaging or biochemical measure independently predictive of outcome.

Indexed extracellular volume was associated with AVR or death, but not after adjusting for EF1.

Conclusions: EF1 is a simple robust marker of early left ventricular impairment that can be precisely measured by CMR & predicts outcome in aortic stenosis.

Its measurement by CMR is more reproducible than that by TTE & may facilitate left ventricular structure–function analysis.

Keywords

• Aortic stenosis
• Cardiovascular magnetic resonance
• Echocardiography
• First-phase ejection fraction