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This study aimed to investigate whether coarctation of the aorta in infancy indicates an altered vascular reactivity in the peripheral and coronary arteries apart from the secondary effect of hypertension or other complications of the disease. Patients with repaired coarctation of the aorta have a high prevalence of premature cardiovascular complications. The etiology still is not fully understood, and the cause is most likely multifactorial. Endothelial function was assessed by peripheral flow mediated dilation (FMD) and coronary flow reserve (CFR) in a study of 10 control subjects and 10 patients with a successfully repaired coarctation of the aorta (mean age, 20.9 years; 20.5 years after repair). No one had re- or rest-coarctation of the aorta, hypertension, pathologic blood pressure response during exercise, or associated cardiac malformations such as bicuspid aortic valve. CFR was achieved by phase-contrast velocity encoding cine magnetic resonance imaging in the coronary sinus before and during infusion with adenosine (0.14 mg/kg/min). FMD was measured in the brachial artery before and after 5 min of arterial occlusion. A normal CFR and FMD was found in both groups. Most studies have been conducted with large, unselected groups. The current study group represented the best outcome of the coarctation spectrum (i.e., patients with no evidence of a residual gradient across the coarctation site or systemic hypertension). The findings reassuringly suggest that significant endothelial dysfunction and atherosclerotic changes were not present in this selected cohort.

This study aimed to evaluate CFR by assessing blood flow in the coronary sinus and systemic endothelial function measured by FMD of the brachial artery in an open prospective study of 10 control subjects and 10 patients (ages, 15–25 years) who have undergone surgical TOF repair. Reduced ventricular function, impaired exercise capacity, and ventricular arrhythmia have been proposed as risk factors for sudden cardiac death after surgical repair of TOF. Some of this may be related to impaired myocardial perfusion. A 3.0T GE Signa Excite scanner was used to achieve phase-contrast, velocity-encoding cine magnetic resonance imaging in the coronary sinus before and during infusion with adenosine (0.14 mg/kg/min). FMD was measured in the brachial artery before arterial occlusion and 5 min afterward. The TOF group demonstrated significantly higher volumetric blood flow in the coronary sinus (282 ± 63 ml/min) than the normal control subjects at rest (184 ± 57 ml/min) (P = 0.006). During adenosine infusion, this difference disappeared. The CFR was 2.00 ± 0.43 in the control group and 1.19 ± 0.34 in the TOF group (P = 0.002). No correlation between FMD and CFR was observed in the study group (r s = 0.61, n = 8, P = 0.15). This study showed a reduced CFR due to a higher blood flow of the subject at rest in the TOF group. This reduced CFR may disable a normal adaptation to increased oxygen demand during exercise and increase myocardial vulnerability to reduced blood supply postoperatively for TOF patients with coronary heart disease.