Quantitative assessment of cardiac allograft vasculopathy by real-time myocardial contrast echocardiography: a comparison with conventional echocardiographic analyses and [Tc99m]-sestamibi SPECT.

Aim: To evaluate the additional benefit of visual and quantitative perfusion measurements compared with conventional real-time myocardial contrast echocardiography (MCE) in the detection of CAV.

Methods And Results: Thirty patients (26 males, age 58 +/- 9.6 years) underwent dobutamine stress echocardiography (DSE) and myocardial perfusion imaging (MPI) as well as coronary angiography (CA) with intravascular ultrasound (IVUS). Ultrasound images were analysed off-line, evaluating (1) wall motion and thickening at high mechanical index ('conventional evaluation'), (2) the MCE loops stored during continuous infusion of contrast agent with regard to visual changes (stress vs. rest, 'visual grading'), and (3) the replenishment curves of the contrast agent at low mechanical index after bubble destruction ('quantitative grading'). CA/IVUS plus MPI showed ischaemia in seven and myocardial scars in nine patients. Sensitivity, specificity, NPV, PPV and accuracy for the detection of ischaemia representing functionally relevant CAV were, respectively, 0.71, 0.83, 0.90, 0.55 and 0.80 for the conventional evaluation alone, 0.71, 0.91, 0.91, 0.71 and 0.87 for additional visual grading and 0.86, 0.91, 0.95, 0.75 and 0.90 for additional quantitative grading.

Conclusion: Real-time MCE including visual and quantitative analysis is feasible for screening patients after HTX and is highly accurate in the diagnosis of haemodynamically relevant CAV.