Differences in Aortic Histopathology in Patients Undergoing Valve Reimplantation Surgery for Various Clinical...

The study aims to investigate aortic histopathologic differences among patients undergoing aortic valve reimplantation, suggest different mechanisms of aortic root aneurysm pathogenesis, and identify factors associated with long-term success of reimplantation.

From 2006 to 2017, 568 adults who underwent reimplantation for repair of aortic root aneurysm, including patients with tricuspid aortic valves with no connective tissue disease (TAV/NoCTD, n = 314/568; 55.3%), bicuspid aortic valves (BAVs, n = 86/568; 15.1%), or connective tissue disease (CTD, n = 177/568; 31.2%), were compiled into three comparison groups. Patients with both BAV and CTD (n = 9/568; 1.6%) were omitted to increase study power. Patient records were analyzed retrospectively, focusing on pathology reports, which were available for 98.42% of patients, and were classified based on their descriptions of aortic tissue samples, primarily from the noncoronary sinus. Mean follow-up time available for patients was 2.97 years.

Aortitis, medial fibrosis, and smooth muscle loss were more common histopathologic findings in patients with TAV/NoCTD than in patients with BAV and CTD (p < 0.05). Cystic medial degeneration was most often found in patients with CTD, then TAV/NoCTD, and least in BAV (p < 0.01). Increases in mucopolysaccharides were found more often in the BAV group than in the TAV/NoCTD and CTD groups (p < 0.01). There were no differences in the frequency of elastic laminae fragmentation/loss across these three groups. Among all patients, 1.97% (n = 11/559) had an unplanned reintervention on the aortic valve after reimplantation, but no significant demographic or histopathologic differences were identified.

Despite some common histopathologic features among patients undergoing aortic valve reimplantation, there were enough distinguishing features among aortic tissue samples of TAV/NoCTD, BAV, and CTD patients to suggest that these groups develop root aneurysms by different mechanisms. No histopathologic features were able to predict the need for late reintervention on the aortic valve.