Comprehensive Non-invasive Versus Invasive Approach to Evaluate Cardiac Allograft Vasculopathy in Heart Transplantation: The CCTA-HTx Study

Background: Coronary computed tomography angiography (CCTA) is emerging as a valuable tool for noninvasive surveillance of cardiac allograft vasculopathy (CAV) in patients with heart transplant (HTx). We assessed the diagnostic performance of a comprehensive CCTA-based approach compared with the invasive reference, which includes invasive coronary angiography, intravascular ultrasound, and fractional flow reserve, for detecting CAV. Methods: This was a multicenter prospective study including 37 patients with HTx who underwent CCTA, invasive coronary angiography, intravascular ultrasound, and fractional flow reserve. The comprehensive CCTA-based approach included quantitative and qualitative plaque analysis and functional assessment by fractional flow reserve derived from coronary computed tomography. CAV was diagnosed based on invasive coronary angiography (International Society for Heart and Lung Transplantation criteria) and intravascular ultrasound. Univariable logistic regression analysis was performed to test CCTA-derived predictors of CAV. The area under the curve and accuracy indicators were calculated to evaluate the performance and best cutoffs of CCTA predictors of CAV. Results: The median interval between CCTA and HTx was 5 years. Among the 37 recipients, 23 (62.2%) were diagnosed with CAV. The integration of diameter stenosis and plaque morphology (including plaque burden at minimum lumen area >42% and percent atheroma volume >23%) at CCTA yielded the highest diagnostic performance (accuracy, 84%; sensitivity, 83%; specificity, 86%). The integration of ∆fractional flow reserve derived from coronary computed tomography trans-vessel gradient led to increased sensitivity, albeit with decreased specificity and overall accuracy. The noninvasive approach was associated with a lower contrast and radiation dose, compared with the invasive approach. Conclusions: A noninvasive strategy based on CCTA is accurate for managing patients with HTx. CCTA might be considered the preferred imaging modality for annual CAV surveillance after the first year post-HTx.