# Multiparametric quantitative structural and functional cardiac MRI in orthotopic heart transplant recipients with cardiac allograft vasculopathy

## TL;DR

This study shows that advanced MRI techniques can detect early signs of heart disease in transplant patients without invasive procedures.

## Contribution

The study demonstrates that combining functional and tissue MRI parameters can predict cardiac allograft vasculopathy in heart transplant recipients.

## Key findings

- ECV and T2 values were significantly higher in patients with CAV compared to those without.
- Strain rates were reduced in CAV-positive patients, indicating impaired heart function.
- A model combining ECV and strain rates predicted CAV status with high accuracy.

## Abstract

The aim of this study was to verify if multiparametric quantitative CMR can detect mild-to-moderate cardiac allograft vasculopathy (CAV) in patients post-orthotopic heart transplant (OHT). 51 patients (age = 50.0 ± 13.6 years, 29% female) post-OHT 0–6 years (mean 3.2 ± 1.5 years) who underwent CMR from 2011 to 2019 were retrospectively included. Multiparametric CMR included CINE imaging covering the left ventricle (LV), pre- and post-contrast T1 mapping, and T2 mapping, extracellular volume fraction (ECV) calculation, and 2D-feature tracking strain. CAV0 (‘CAV negative’) patient variables were compared with CAV1-CAV2 (‘CAV positive’) variables. Logistic regression was used to determine predictors of CAV status. Myocardial T2 was higher in CAV positive compared with CAV negative patients (54.5 ± 7.7 ms vs. 50.2 ± 3.3 ms, p < 0.05), as was ECV (31.3 ± 5.3% vs. 27.4 ± 4.1%, p < 0.05). Radial and circumferential peak systolic strain rates were attenuated in CAV positive vs. CAV negative patients (radial: 1.4 ± 0.4 s-1 vs. 1.8 ± 0.3 s-1, circumferential: -0.9 ± 0.2 s-1 vs. -1.1 ± 0.1 s-1, p < 0.05),as well as circumferential and longitudinal peak diastolic strain rates (0.7 ± 0.7 s-1 vs. 1.0 ± 0.5 s-1, and 0.8 ± 0.3 s-1 vs. 0.9 ± 0.3 s-1, p < 0.05, respectively). CAV positive vs. negative status correlated with ECV (rho 0.41, P < 0.01), T2 (rho 0.29, p < 0.05), radial and circumferential peak systolic strain rate (rho − 0.48, P < 0.01 and rho 0.47, p < 0.001, respectively), and circumferential and longitudinal peak diastolic strain rates (rho − 0.34, p < 0.05 and rho − 0.35, p < 0.01, respectively). Logistic regression revealed that a model including ECV, peak radial and circumferential systolic strain rates and longitudinal diastolic strain rate was significant for distinguishing CAV positive vs. negative status with a receiver operator characteristic area under curve of 0.85 ± 0.06 (CI 0.73–0.97), p < 0.005. A model combining functional (strain) and tissue parameters (ECV) was predictive of CAV status, indicating the potential of multiparametric CMR for non-invasive prediction of CAV status in OHT recipients.