Role of Coronary CT in Predicting Cardiovascular Prognosis After Heart Transplantation

Cardiac allograft vasculopathy (CAV) is the main long term cause of death after heart transplantation (HTx). ISHLT guidelines for CAV assessment suggest a role for coronary tomography (CT); however, its prognostic predicting power is unknown, and few data are avalaible about the significance of scoring calcified plaques. Our study’s aim was to investigate the role of CT in predicting cardiovascular (CV) prognosis in HTx patients (pts). In this retrospective study of prospective collected data, all pts transplanted in Vienna between 2001-08 with a CT assessment for CAV, were enrolled. A CAV positive CT was labeled as any detected irregularity (stenosis, vessel wall irregularity, calcifications) for better matching with the ISHLT CAV grading system; calcium score (CS) was collected. The endpoints were freedom from CV death and from combined MACE occurrence (CV death, admission for HF, PCI, re-HTx), expressed as 5-yrs survival rates. 155 pts entered into the study (81.2% males, 50.3±14.0 yrs at HTx). CT scan was made 44±24 months after HTx; 34.8% of pts had a CAV positive CT, 25% a positive (>0) CS. Any irregularity in the first CT scan predicted both CV death (98.9±0.1% vs. 89.0±4.7%, p=0.01) and MACE (96.4±2.0% vs.77.2±6.1%, p<0.01). A positive CS predicted MACE (94.0±2.3% vs. 78.6±7.3%, p=0.01) but not CV death. At multivariate analysis, only CT irregularity predicted MACE [OR 2.5 (95% CI 1.1-5.2), p<0.0002]. 115 pts underwent a second CT, 22±12 months after the first one; 27.8% of them had a CAV progression (increase of a stenosis, new onset stenosis, higher CS); among the 102 in which CS was calculated, the ones who experienced an increase in CS (28) had a higher rate of MACE (98.6±1.3% vs. 82.4±9.5%, p=0.03). Among the 39 pts who had a coronary angiography within 6 months from the CT, the ones with CT-detected CAV had a higher rate of angiography detected CAV (88.9% vs. 47.6%,p=0.006); a CT negative for CAV predicted a negative angiography with a 84% sensitivity and a 62% specificity (AUC 0.73,p=0.004). CT -detected coronary irregularities can predict CV death and MACE. CS may be used only as a longitudinal parameter to predict CV prognosis in a subset of patients. Even if its sensitivity in CAV assessment is lower than angiography, our study suggests that CT could be used a non-invasive screening tool for predicting prognosis in selected HTx patients.