Descending Aortic Distensibility and Cardiovascular Outcomes: A Cardiac Magnetic Resonance Imaging Study

BACKGROUND: Aortic distensibility (AD) is an important determinant of cardiovascular (CV) morbidity and mortality. There is scant data on the association between AD measured within the descending thoracic aorta and CV outcomes. OBJECTIVE: We evaluated the association of AD at the descending thoracic aorta (AD (desc)) with the primary outcome of all-cause mortality, myocardial infarction (MI), stroke or coronary revascularization in patients referred for a cardiovascular magnetic resonance (CMR) study. METHODS: 928 consecutive patients [(mean age 60 ± 17; 33% with prior cardiovascular disease (CVD))] were evaluated. AD (desc) was measured at the cross-section of the descending thoracic aorta in the 4-chamber view (via steady-state free precession [SSFP] cine sequences) and was grouped into quintiles (with the 1st quintile corresponding to the least AD, i.e., the stiffest aorta). Cox proportional-hazards regression analysis were performed for the primary outcome. RESULTS: A total of 315 patients (34%) experienced the primary outcome during a median (25% IQR, 75% IQR) follow-up of 5.0 (0.56, 9.3) years. A decreased AD was significantly associated with hypertension, diabetes, renal disease, and dyslipidemia (p <0.0001). A primary outcome occurred in 43% of patients with AD (desc) ≤ median compared to 25% with AD (desc) > median, p <0.0001, and in 44% of patients with AD (desc) in the 1st quintile compared to 31% with AD (desc) in the other quintiles (p = 0.0004). Event free survival was incrementally reduced amongst quintiles (p <0.0001). However, AD (desc) ≤ median was not an independent predictor of the primary endpoint after multivariable adjustment in the overall population [adjusted HR 1.09 (95% CI:0.82–1.45), p = 0.518] or in the subgroup analysis of patients with or without prior CVD. CONCLUSION: In this real-world cohort of 928 patients referred for CMR, AD (desc) is not an independent predictor of CV outcomes.