Diagnostic and Prognostic Value of Myocardial Extracellular Volume Fraction Assessed Using Cardiovascular Magnetic...

Restrictive cardiac allograft physiology (RCP) is associated with poor prognosis following heart transplantation (HT). While cardiac magnetic resonance (CMR) is useful for evaluating HT recipients, its utility for RCP assessment remains unknown. This study aimed to investigate the diagnostic and prognostic value of CMR in patients with RCP.

Seventy-five HT recipients (median age: 54 [interquartile range (IQR), 40-63] years; 33.3% female) who underwent contrast-enhanced CMR between 2015 and 2023 were included. Patients were grouped by RCP status (RCP⁺ group, n = 30; and RCP^- group, n = 45). RCP was defined according to the International Society for Heart and Lung Transplantation guidelines. The primary endpoints were all-cause mortality or redo HT.

The median HT-to-CMR time was 4.6 (IQR, 1.2-11.0) years. Compared to that of the RCP^- group, the RCP⁺ group exhibited significantly higher myocardial T2 (53.1 ± 7.5 vs. 49.7 ± 5.7 ms; p = 0.035) and extracellular volume fraction (ECV) (33.4 ± 6.8% vs. 28.6 ± 6.1%; p = 0.003) values. Multivariate logistic regression analyses revealed an independent association between ECV and RCP (odds ratio = 1.11; 95% CI: 1.02-1.23; p = 0.032). The area under the receiver operating characteristic curve for ECV was 0.73, with 60.7% sensitivity and 83.3% specificity at a cutoff value of 31.5%. After ECV-dependent stratification of patients with RCP, Kaplan-Meier analysis demonstrated significantly higher incidences of primary endpoints in the ECV ≥ 31.5% subgroup than in the ECV < 31.5% subgroup (p = 0.048).

CMR-derived myocardial ECV provides both diagnostic and prognostic value in patients with RCP and may potentially help guide the timing for consideration of re-HT.