Increased aortic wall stiffness is predictive of aortic dilation in adult patients following coarctation of the aorta repair

Patients after repaired coarctation of the aorta are at risk for dilation and dissection of both the ascending and descending aorta. Histologic abnormalities seen are indistinguishable from patterns seen with Marfan syndrome, and lead to a stiff aortic wall, characterized by decreased distensibility, strain, and increased B-stiffness. We sought to analyze the relationship of aortic wall stiffness measured by cardiac MRI to aortic dilation following coarctation of the aorta repair. Fifty-two adult patients (26 females) with history of previous coarctation of the aorta repair who had undergone a recent cardiac MRI were identified. Studies and charts were reviewed retrospectively. Aortic strain, distensibility, and B-stiffness values were measured at level of ascending aorta and descending aorta. Relationships between measurements of aortic stiffness were compared to aortic dimensions. Median age at coarctation repair was 0.2 years (range 0.1-36 years). Types of repair included subclavian artery flap (44%), end-to-end anastomosis (33%), and patch angioplasty (15%). Time from repair to cardiac MRI was 25 years (range 1-42). By cardiac MRI, 38% had a dilated ascending aorta defined as a Z-score of >2.5. On average the ascending aorta was stiffer than the descending aorta for all three parameters. For both the ascending and descending aorta the 3 parameters of aortic stiffness were predictive of increasing aortic dimensions (P value < 0.01). By univariate analysis, risk factors for a dilated ascending aorta defined as a Z-score of >2.5 included older age at the time of initial repair, presence of a bicuspid aortic valve, and worse parameters of ascending aorta stiffness: % strain, distensibility, and B-stiffness, and a lower descending aorta % strain. By multivariate analysis, older age at initial repair and both a lower % strain at both the ascending and descending aorta remained statistically significant.