Use of exercise electrocardiography, technetium-99m-MIBI perfusion tomography, and two-dimensional echocardiography for coronary disease surveillance in a low-prevalence population of heart transplant recipients
BACKGROUND: Coronary artery disease has been reported to be a significant cause of long-term morbidity and mortality after heart transplantation. However, the diagnosis of coronary disease by means of noninvasive procedures has shown disappointing accuracy, and many centers currently recommend an annual surveillance coronary angiogram. METHODS: We prospectively studied the accuracy and feasibility of a symptom-limited upright bicycle exercise, combined with computerized electrocardiogram analysis, echocardiography, and perfusion scintigraphy in 37 consecutive heart transplant recipients at 2.8 +/- 1.4 years after transplantation for routine follow-up coronary angiography. RESULTS: No patient had any hemodynamically significant (> 50% diameter) coronary stenosis, but luminal irregularities were detectable in four patients. The exercise electrocardiogram was interpretable in only 22 patients (59%), and two of the remaining patients (9%) had false-positive results. The feasibility of perfusion tomography (100%) and two-dimensional echocardiography (97%) were greater than for stress electrocardiogram (p < 0.001 and p < 0.01 respectively). False-positive results were obtained at stress echocardiography in one patient (3%), and at scintigraphy in six patients (16%, p = not significant). None of these methods detected coronary artery stenoses of less than 50% diameter. CONCLUSIONS: Both exercise perfusion tomography and two-dimensional echocardiography are feasible and can be used with adequate specificity for the noninvasive diagnosis of coronary artery disease in heart transplant recipients. However further studies are needed to determine their respective sensitivity.