Follow-Up of Heart Transplant Recipients with Serial Echocardiographic Coronary Flow Reserve and Dobutamine Stress Echocardiography to Detect Cardiac Allograft Vasculopathy

Background: Implementation of reliable noninvasive testing for screening cardiac allograft vasculopathy (CAV) is of critical importance. The most widely used modality, dobutamine stress echocardiography (DSE), has moderate sensitivity and specificity. The aim of this study was to assess the potential role of serial coronary flow reserve (CFR) assessment together with DSE for predicting CAV. Methods: A total of 90 studies were performed prospectively over 5 years in 23 consecutive heart transplant recipients who survived > 1 year after transplantation. Assessment of CFR with transthoracic Doppler echocardiography, DSE, coronary angiography, and endomyocardial biopsy was performed annually. Results of CFR assessment and DSE were compared with angiographic findings of CAV. Results: Acute cellular rejections were excluded by endomyocardial biopsies. CAV was detected in 17 of 90 angiograms. Mean CFR was similarly lower in both mild (CAV grade 1) and more severe (CAV grades 2 and 3) vasculopathy, but wall motion score index became higher in parallel with increasing grades of vasculopathy. Any CAV by angiography was detected either simultaneously with or later than CFR impairment, yielding 100% sensitivity for CFR. The combination of CFR and DSE increased the specificity of the latter from 64.3% to 87.2% without compromising sensitivity (77.8%). Conclusions: CFR is very sensitive for detecting CAV and increases the diagnostic accuracy of DSE, raising the potential for patient management tailored to risk modification and to avoid unnecessary angiographic procedures.