Abnormal vasomotor function of the epicardial coronary arteries in children five to eight years after arterial switch operation: An angiographic and intracoronary Doppler flow wire study

OBJECTIVES: This study sought to test the vasoreactivity of the translocated coronary arteries after arterial switch operation (ASO) using quantitative angiographic analysis and intracoronary Doppler flow wire velocimetry. BACKGROUND: Late coronary artery events occur in 3% to 8% of patients after the ASO. Previous studies of coronary flow reserve have yielded disparate results. METHODS: Nineteen children previously underwent ASO (13 boys, age 5.4 ± 3.2 years, weight 22.3 ± 10.6 kg), and six control patients were enrolled in the study. Each patient underwent quantitative angiographic assessment of the epicardial coronary arteries before and after administration of nitroglycerin and coronary blood flow volume assessment before and after administration of adenosine and acetylcholine. The results were compared between groups. RESULTS: Epicardial coronary artery dilation in response to intracoronary nitroglycerin was significantly less in the ASO group than in the control group (left anterior descending [LAD], 5.0 ± 0.05% vs. 18.0 ± 4.5%, p = 0.0009; right coronary artery [RCA], 4.0 ± 0.07% vs. 32.7 ± 12.7%, p = 0.006). Moreover, the coronary blood flow volume reserve was reduced in ASO patients compared with control patients after intracoronary infusion of acetylcholine (2.3 ± 0.9 vs. 4.9 ± 1.7, p = 0.0003) or adenosine (2.7 ± 1.5 vs. 5 ± 0.5, p = 0.002). CONCLUSIONS: Epicardial coronary arteries fail to dilate normally in children after ASO, and the calculated coronary flow volume reserve is consequently reduced.