['Despite repair of aortic coarctation, hypertension is frequent in adults and premature coronary and cerebrovascular disease remain of concern. Persistent impairment of arterial dilation has been suspected to contribute to abnormal blood pressure regulation. We tested the hypothesis that arterial reactivity is more likely to be impaired in patients corrected at older age.', 'We studied changes in brachial artery diameter in response to reactive hyperemia (FMD) and to nitroglycerin (NMD) in 36 patients and 25 controls. Depending on their age at surgery, patients were divided in group A (surgery <9 years) and group B (surgery > or =9 years).', 'Cholesterol levels and percentage of smokers were similar in patients and controls, but 16 patients had arterial hypertension compared to none of the controls. Endothelium-dependent vasodilation, FMD, and endothelium-independent vasodilation, NMD, were significantly impaired in patients vs. controls (8.2+/-6.2% vs. 13.0+/-5.1%, p<0.001 and 12.9+/-8.0% vs. 18.8+/-9.2%, p<0.01, respectively), both, in hypertensives (8.3+/-6.0%, p<0.01 and 11.8+/-6.0%, p<0.05) and in normotensives (8.1+/-6.5% p<0.01 and 13.8+/-9.3%, p<0.05). However, FMD and NMD in patients of group A did not significantly differ from that in controls (10.0+/-6.7% n.s. and 15.0+/-7.6% n.s.), whereas they were lowest in patients of group B (5.5+/-4.3%, p<0.0001 and 9.6+/-7.7% p<0.001).'] Is vascular dysfunction after coarctation repair related to the age at surgery?