Background: Coronary angiography is still the routine screening method for cardiac allograft vasculopathy in most transplant centers. This study was designed to analyze functional and morphologic changes in heart transplant recipients with normal angiographic findings.
Methods: Dobutamine stress echocardiography and intracoronary ultrasound were obtained in 56 patients with a normal coronary angiogram 41+/-31 months after heart transplantation. Intracoronary Doppler flow velocity measurements before and after intracoronary adenosine administration were performed in 34 of 56 patients. Any regional wall motion abnormalities detected by stress echocardiography were regarded as abnormal. By quantitative intracoronary ultrasound analysis using a 6-grade scale, a mean grade of all coronary segments >3.0 was defined as significant intimal hyperplasia.
Results: Only 17 patients (30%) showed both a normal dobutamine stress echocardiogram and absence of significant intimal hyperplasia by intravascularultrasound. Abnormal findings were observed in 39 patients (70%): both by dobutamine stress echocardiography and intravascular ultrasound in 22 patients, by intravascular ultrasound alone in 11 patients, and by dobutamine stress echocardiography alone in 6 patients. Coronary flow velocity reserve did not discriminate between patients with normal or abnormal intravascular ultrasound or dobutamine stress echocardiographic findings.
Conclusions: Only a minority of heart transplant patients with a normal coronary angiogram is free of pathological changes, when assessed by intravascular ultrasound and dobutamine stress echocardiography. Coronary flow velocity reserve does not seem useful to further characterize these patients.