Identification of Coronary Artery Disease in the Pediatric Cardiac Transplant Patient

Abstract

Little data exist to identify pediatric patients who have developed transplant coronary artery vasculopathy (CAV). Transplant patients do not exhibit the usual signs of coronary disease, making diagnosis more difficult. The aim of this study is to assess the use of myocardial perfusion imaging to identify CAV in transplant patients and to derive an incidence of occurrence. We studied pediatric cardiac transplant recipients who have undergone myocardial perfusion imaging on a routine basis. All patients from September 1999 through November 2004 with nuclear perfusion scans were included. Twenty patients age 7-24 years (mean: 12.7), 11 male and 9 female, were studied by SPECT technetium 99M tetrofosmin imaging. Sixteen of the 20 patients were studied based on a newly instituted protocol for surveillance. Transplant was 1-14 years (mean: 7.9) earlier. Patients were also studied by stress echocardiography. Six of 20 patients (30%) had a positive perfusion scan. Ages ranged from 8 to 18 years (mean: 12). Time from transplant to positive scans ranged from 1 to 9 years (mean: 5.6). One patient showed the same perfusion defect as 2 years earlier. Five patients with positive nuclear perfusion scans showed the abnormality on the initial study; one had a previous negative study 6 months earlier. Four patients who demonstrated ischemia with exercise showed resolution at rest; the other two had no resting study. Five of these six patients with abnormal perfusion scans had negative stress echocardiograms. Only one patient identified with coronary involvement reported symptoms (exertional dyspnea). Hypertension and rejection episodes were similar in all patients and in those with positive nuclear scans. Of the six patients with positive nuclear perfusion scans, two demonstrated coronary disease at cardiac catheterization. Two patients with coronary disease at catheterization had normal nuclear perfusion scans; one of two had a normal stress echo. When three imaging modalities were used, the incidence of CAV was 30%. Symptoms in pediatric patients with CAV are seldom reported. Unfortunately, coronary arteriopathy occurs frequently and might be found as early as 1 year posttransplant. Six of 20 patients had abnormal perfusion; only 1 had any other noninvasive marker. Importantly, not all patients with CAV were identified by perfusion imaging, stress echocardiography, or coronary injection alone. Therefore, transplant patients need continued evaluation by multiple modalities for detection of developing coronary lesions.