Hypertension at rest or during effort is not uncommon in patients with aortic coarctation (CoA), even those with a successful repair or mild degree of obstruction. Anatomic factors and functional abnormalities have been proposed as causes of this finding. Recently, aortic arch geometry was reported in association with hypertension at rest in patients with successful CoA repair. Forty-one patients (age 15.7 +/- 4.6 years) without significant obstruction at rest (mean systolic Doppler gradient at rest < or =25 mm Hg) were selected for the study. All patients underwent a maximal cardiopulmonary exercise test and magnetic resonance imaging of the aorta. Aortic arch shape was defined on global geometry as normal, gothic, and crenel. Percentage of anatomic narrowing (AN) was also calculated. Twenty-four patients (58%) showed exercise-induced hypertension (EIH). Regarding the shape of the aortic arch, normal geometry was present in 17 patients (41%), 9 (21%) had gothic geometry, and 15 (36%) had crenel geometry. There were no differences among the 3 geometries in regard to the incidence of EIH (70.6% in normal, 55.6% in gothic, and 46.7% in crenel) or AN (36.9% in normal, 33.5% in gothic, and 36.6% in crenel). In conclusion, our results fail to show a correlation between a specific aortic arch shape and the incidence of EIH and significant AN in patients with native or residual CoA or repeat CoA. Therefore, at present, the role of aortic arch geometry in identifying patients at risk of EIH is still uncertain.