Abnormalities of Aortic Arch Shape, Central Aortic Flow Dynamics, and Distensibility Predispose to Hypertension After Successful Repair of Aortic Coarctation

Abstract

Background: Systemic hypertension (HT) is a major long-term complication even after successful repair of aortic coarctation (CoA), and many factors are involved in this pathophysiology. Objective: To investigate the role of abnormalities in the aortic arch shape, central aortic flow dynamics, and distensibility in developing HT after successful repair of CoA. Methods: We selected a group of 26 normotensive patients (mean age 16.9 ± 7.3 years, range 9-32 years) with anatomically successful repair of CoA among 140 patients regularly followed after repair of CoA and analyzed their last clinical and echocardiographic data. Bicycle exercise test and ambulatory blood pressure monitoring (ABPM) were also obtained. Mean age at surgical repair was 3.2 ± 3.9 years (range 10 days-15 years); 12 patients underwent surgical correction during the first year of life. Repair of CoA was performed by end-to-end anastomosis (TT) in 23 patients (extended TT in 6 patients with arch hypoplasia), patch aortoplasty in 2, and subcalvian flap aortoplasty in 1. The postsurgical follow-up was 13.8 ± 7.2 years (range 3.5-29.4 years). The shape of the aortic arch was defined by magnetic resonance imaging (MRI) on this global geometry (normal–gothic–crenel), ratio of the height–transverse diameter (A/T), percentage of residual stenosis, and growth index of the transverse arch segments. Flow mapping by phase-contrast imaging in the ascending and descending aorta was performed in order to measure the systolic waveforms and central aortic distensibility. Twenty normal age-matched patients submitted to the same MRI protocol were used as controls. Results: Six patients were found to have a gothic and 20 a normal aortic arch shape. Patients with gothic aortic arch shape had an increased A/T ratio (0.80 ± 0.07 vs 0.58 ± 0.05, P < .001), a greater loss of systolic wave amplitude across the aortic arch (43% ± 2% vs 34% ± 5%, P < .001), and a lower distensibility of the ascending aorta compared to those with normal shape (4.87 ± 1.06 mm Hg−1×10−3 vs 7.20 ± 1.73 mm Hg−1 × 10−3; P = .005) and controls (4.87 ± 1.06 mm Hg−1×10−3 vs 8.57 ± 1.71 mm Hg−1×10−3; P < .001). The maximal systolic blood pressure (SBP) on exercise as well as SBP, diastolic blood pressure, and percentage of >135 mm Hg on ABPM were higher in the gothic than in the normal arch group. There was a correlation between nocturnal SBP, 24 hours pulse pressure on ABPM in the whole group, and different MRI variables (A/T, distensibility of the ascending aorta, and percentage of loss of systolic wave amplitude). Conclusions: In the long-term follow-up after CoA repair, a gothic arch shape is associated with a decreased ascending aorta distensibility with an increased loss of systolic wave amplitude across the aortic arch. These findings explain at least in part the association between this abnormal arch geometry and late HT at rest and on exercise, left ventricular hypertrophy, and adverse cardiovascular outcome in this group of young adults with successful repair of CoA.