Prognosis of Unrepaired Ascending Aorta after the Surgical Replacement of Bicuspid Aortic Valves

BACKGROUND: The surgical threshold for bicuspid aortic valve (BAV)-related aortopathy is a matter of debate due to its uncertain etiology and prognosis. This study investigated the prognosis of unrepaired BAV aortopathy in patients undergoing surgical aortic valve replacement (SAVR). METHODS: We retrospectively analyzed data from 720 patients (age, 60.8±11.5 years; 246 women) who underwent SAVR for BAV disease without aortic repair between 2005 and 2020 at Asan Medical Center. The clinical endpoints were defined as occurrences of sudden death, aortic dissection or rupture, and elective aortic repair. To estimate postoperative changes in the dimensions of the unrepaired aorta, the individual annual aortic expansion rate was calculated. Multiple linear regression models were used to evaluate the risk of aortic expansion. RESULTS: The mean ascending aortic diameter was 39.5±4.6 mm, and 299 patients (41.5%) had a baseline ascending aorta diameter >40 mm. During 70.0±68.3 months of follow-up, the mean annual aortic expansion rate was 0.39±1.96 mm/yr, no aortic dissection or rupture was observed, and sudden deaths were reported in 12 patients (0.34% per person-year). Linear regression analysis revealed no significant correlation between the baseline ascending aortic diameter and postoperative aortic expansion (R(2)=0.004, β=-0.84, p=0.082). CONCLUSION: In selected patients undergoing SAVR for a BAV (<55 mm), the risk of adverse aortic events was very low. As this observation contradicts current practice guidelines advocating for proactive aortic replacement in dilated ascending aortas measuring >45 mm, the study results need further validation by studies involving larger populations or randomized controlled trials.