Revisiting ascending aortic resection in the elective valve-sparing root replacement: assessing the benefits and necessity of hemiarch replacement at three centres.

Objectives
The aim of this study was to determine the indication and optimal timing for performing a hemiarch procedure in patients undergoing valve-sparing root replacement (VSRR).Methods
We conducted a retrospective study on 986 patients undergoing VSRR at three tertiary care centres. Inclusion criteria were all patients undergoing elective VSRR. Exclusion criteria were age <18 years, Stanford type A dissection, dissection in the arch, total aortic arch replacement or previous aortic arch replacement. We performed propensity score matching in a 1:1 ratio. The primary endpoint is a composite outcome that includes mortality, aortic arch reintervention, new aortic dissection during follow-up, and cerebrovascular incidents within the first 30 days.Results
A total of 401 patients (41%) had a hemiarch replacement, while 585 (59%) did not. Root phenotype was present in 565 (57%). The mean follow-up time was 4.7 years (SD ± 4.6).In the matched population, there was no significant difference in the 10-year freedom from the composite outcome between the non-hemiarch and hemiarch groups (87.3% vs. 85.0%, p > 0.999). Similarly, no difference was found for aortic reinterventions (p = 0.13) or survival (p = 0.5). This was also true for patients with heritable thoracic aortic disease. However, in patients with a bicuspid aortic valve, the intervention rate was significantly higher in the hemiarch group (10.8% vs. 0%, p = 0.016).There was no significant difference in the 30-day incidence of cerebrovascular accidents between the groups (5% vs. 2.7% in the hemiarch group, p = 0.117). Only the distal ascending diameter showed a tendency with better outcome over 45mm for the hemiarch procedure, otherwise we found no reliable cut-off values based on asecending length, diameter-to-height index, or ascending length-to-height index.Conclusions
Our findings conclusively demonstrate that concomitant hemiarch replacement does not increase the perioperative risk in young patients undergoing VSRR. However, concomitant replacement does not seem to protect from aortic reinterventions during medium term follow-up.