Rapid ascending aorta stiffening in bicuspid aortic valve on serial cardiovascular magnetic resonance evaluation: comparison with connective tissue disorders

BACKGROUND: Aortic stiffness has been shown to be abnormal in patients with bicuspid aortic valve (BAV), and is considered a component of the aortopathy associated with this condition. Progressive aortic stiffening associated with aging has been previously described in normal adults. However, it is not known if aging related aortic stiffening occurs at the same rate in BAV patients. We determined the longitudinal rate of decline in segmental distensibility in BAV patients using serial cardiovascular magnetic resonance (CMR) studies, and compared to previously published results from a group of patients with connective tissue disorders (CTD). METHODS: A retrospective review of CMR and clinical data on children and adults with BAV (n = 49, 73% male; 23 ± 11 years) with at least two CMRs (total 98 examinations) over a median follow-up of 4.1 years (range 1–9 years) was performed to measure aortic distensibility at the ascending (AAo) and descending aorta (DAo). Longitudinal changes in aortic stiffness were assessed using linear mixed-effects modeling. The comparison group of CTD patients had a similar age and gender profile (n = 50, 64% male; 20.6 ± 12 years). RESULTS: Compared to CTD patients, BAV patients had a more distensible AAo early in life but showed a steeper decline in distensibility on serial examinations [mean 10-year decline in AAo distensibility (× 10(−3) mmHg(−1)) 2.4 in BAV vs 1.3 in CTD, p = 0.005]. In contrast, the DAo was more distensible in BAV patients throughout the age spectrum, and DAo distensibility declined with aging at a rate similar to CTD patients [mean 10 year decline in DAo distensibility (× 10(−3) mmHg(−1)) 0.3 in BAV vs 0.4 in CTD, p = 0.58]. CONCLUSIONS: On serial CMR measurements, AAo distensibility declined at significantly steeper rate in BAV patients compared to a comparison group with CTDs, while DAo distensibility declined at similar rates in both groups. These findings offer new mechanistic insights into the differing pathogenesis of the aortopathy seen in BAV and CTD patients.