Role of Cardiovascular Magnetic Resonance in Post-Heart Transplant Surveillance: Integrating Evidence with...

Background: Heart transplantation remains the definitive therapy for selected patients with end-stage heart failure, but outcomes are limited by acute rejection, chronic allograft injury, and cardiac allograft vasculopathy. Endomyocardial biopsy (EMB) remains the reference standard for rejection surveillance but is invasive and imperfectly captures diffuse myocardial injury. Cardiovascular magnetic resonance (CMR) offers noninvasive, multiparametric assessment of graft structure, function, tissue composition, and perfusion. We aimed to review current evidence supporting CMR in post-heart transplant surveillance and to evaluate the performance of serial CMR for acute cellular rejection in a prospective cohort. Methods: We performed a focused narrative review of the literature on CMR for detection of acute rejection, assessment of chronic allograft injury and prognosis, and evaluation of cardiac allograft vasculopathy and microvascular disease. In parallel, we conducted a prospective observational study of adult heart transplant recipients undergoing early post-transplant CMR (CMR1) and follow-up CMR (CMR2) with temporally matched EMB. Multiparametric CMR included cine imaging, native T1 and T2 mapping, extracellular volume fraction (ECV), and late gadolinium enhancement (LGE). Clinically significant acute cellular rejection was defined as ISHLT grade ≥ 2R. Results: Eighteen recipients were included (median 53 days to CMR1 and 192 days to CMR2). Baseline CMR parameters correlated with invasive hemodynamic and biomarkers. Two patients had biopsy-proven ≥2R rejection at follow-up. T2 values at CMR2 were significantly higher in rejection versus non-rejection patients (59.0 ± 1.4 ms vs. 51.1 ± 1.9 ms; p = 0.015), with greater LGE burden in rejection (p = 0.029). In longitudinal analyses, rejection was associated with divergent patterns of cardiac remodelling and tissue characterization, including increases in indexed ventricular volumes and T2 over time, whereas non-rejection patients demonstrated stable ventricular volumes and a decline in T2. Conclusions: Multiparametric CMR, anchored by T2 mapping, provides clinically meaningful, non-invasive information for acute rejection surveillance after heart transplantation and complements EMB within a personalized, risk-adapted follow-up framework. Establishing individualized baseline CMR phenotypes and monitoring longitudinal changes may support more personalized, less invasive graft surveillance strategies. Larger multicentre prospective studies are needed to define standardized implementation pathways.