Comprehensive non-invasive assessment of cardiac allograft vasculopathy and myocardial involvement in heart transplant patients using cardiac computed tomography.

RATIONALE AND

OBJECTIVES

Cardiac graft rejection and allograft vasculopathy (CAV) are major causes of morbidity and mortality in heart transplant (HT) patients. While endomyocardial biopsy and invasive coronary angiography remain diagnostic gold standards, their invasiveness highlights the need for safer, noninvasive alternatives. Cardiac computed tomography (CT) has emerged as a promising modality for evaluating both coronary and myocardial status.

OBJECTIVES

The primary aim of this study is to evaluate CT-measured extracellular volume (ECVCT) in HT patients compared to a control group and identify its clinical determinants. The secondary objective is to explore the association between ECVCT and CAV severity.

MATERIALS AND

METHODS

In a reference HT center, we conducted a retrospective cohort study of 163 patients comprising 80 HT patients and 83 age- and sex-matched controls without structural heart disease studied with a standardized CT protocol. Twenty-two control patients had concomitant cardiac CT and magnetic resonance (CMR) to validate ECVCT measurements. Determinants of ECVCT including rejection history, CAD-RADS, CAV and cardiovascular risk factors were studied.

RESULTS

Median ECVCT was significantly higher in HT patients (34%, IQR 30-38) compared to controls (29%, IQR 27-31; p < 0.001). ECVCT was highly correlated with MR-ECV (r = 0.88, p < 0.001). In HT recipients, elevated ECVCT was independently associated to hypertension , smoking, presence of CAV, elevated CAD-RADS scores and a history of graft rejection, whereas in controls only higher coronary artery calcium scores correlated with increased ECVCT.

CONCLUSION

ECVCT is increased in HT patients compared to controls and associated with rejection history and CAV. ECVCT emerges as a promising noninvasive tool for the simultaneous assessment of myocardial alterations and CAV in HT patients showing strong concordance with CMR and high reproducibility. Further multicenter studies are warranted to confirm its role in transplant surveillance protocols.