Abstract 2332: Coronary Flow Velocity Reserve by Contrast-Enhanced Transthoracic Echocardiography Predicts Maximal Epicardial Intimal Thickening in Cardiac Allograft Vasculopathy
Cardiac allograft vasculopathy (CAV) is the main limiting factor of long-term survival after heart transplantation (HT). Several noninvasive tests have proven unsatisfactory in CAV diagnosis. We assessed the role of contrast-enhanced transthoracic echocardiography (CE-TTE) during adenosine infusion, a new noninvasive method for determination of coronary flow reserve (CFR).
Methods: CAV was defined as maximal intimal thickness (MIT) assessed by intravascular ultrasound (IVUS) ≥0.5 mm. CFR was assessed in the left anterior descending coronary artery by CE-TTE in 22 HT recipients (20 male, aged 50 ± 7 years at HT), at 6 ± 4 years post-HT. CFR measurements were taken blindly within 24 hours from diagnostic IVUS.
Results: CAV was diagnosed in 11 patients (group A), 11 had normal coronaries (group B). The median MIT was 0.5 mm (range 0 –1.8). MIT was higher in group A (1.03 ± 0.3 mm vs 0.12 ± 0.1 mm, p < 0.0001). CFR was 3.3 ± 0.9 in all patients and lower in group A (2.8 ± 0.1 vs 3.7 ± 0.3, p = 0.03) (figure⇓, left panel) CFR was inversely related with MIT (r = −0.597, p = 0.003) (figure⇓, right panel). A cutpoint of ≤ 3.1, identified as optimal by receiver operating characteristics (ROC) analysis (AUC 0.851, SE 0.085, 95% CI 0.685–1.018, p = 0.005) was 100% specific and 73% sensitive (PPV = 100%, NPV = 79%, Accuracy = 86%) (OR = 3.6, p = 0.001)
Conclusions: CFR assessment by CE-TTE is a novel noninvasive diagnostic tool in the detection of CAV defined as MIT ≥ 0.5 mm, with 86% accuracy by optimal ROC curve derived cutpoint. CFR by CE-TTE may reduce the need for routine IVUS in HT.