Interchangeability in Left Ventricular Ejection Fraction Measured by Echocardiography and cardiovascular Magnetic Resonance: Not a Perfect Match in the Real World.

Comparisons of transthoracic echocardiography (TTE) and cardiovascular magnetic resonance (CMR) derived left ventricular ejection fraction (LVEF) have been reported in core-lab settings but are limited in the real-world setting. We retrospectively identified outpatients from 4 hospital sites who had clinically indicated quantitative assessment of LVEF _TTE and LVEF _CMR and evaluated their concordance. In 767 patients (mean age 47.6 years; 67.9% males) the median inter-modality interval was 35 days. There was significant positive correlation between the 2 modalities (r = 0.75; P < 0.001). Median LVEF was 54% (IQR 47%, 60%) for TTE and 59% (IQR 51%, 64%) for CMR, (P < 0.001). Normal LVEF _TTE was confirmed by CMR in 90.6% of cases. Of patients with severely impaired LVEF _TTE , 42.3% were upwardly reclassified by CMR as less severely impaired. The overall proportion of patients that had their LVEF category confirmed by both imaging modalities was 64.4%; Cohen's Kappa 0.41, indicating fair-to-moderate agreement. Overall, CMR upwardly reclassified 28% of patients using the British Society of Echocardiography LVEF grading, 18.6% using the European Society of Cardiology heart failure classification, and 29.6% using specific reference ranges for each modality. In a multi-site "real-worldˮ clinical setting, there was significant discrepancy between LVEF _TTE and LVEF _CMR measurement. Only 64.4% had their LVEF category confirmed by both imaging modalities. LVEF _TTE was generally lower than LVEF _CMR. LVEF _CMR upwardly reclassified almost half of patients with severe LV dysfunction by LVEF _TTE . Clinicians should consider the inter-modality variation before making therapeutic recommendations, particularly as clinical trial LVEF thresholds have historically been guided by echocardiography.
(Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)