Aortic remodelling following hemiarch versus extended arch repair for acute type a aortic dissection

Acute type A aortic dissection (ATAAD) is a surgical emergency with a high mortality rate. Following surgical repair, the aorta usually develops a distal anastomotic new entry tear (DANE) even with the most meticulous suturing techniques and undergoes remodeling. DANE keeps the false lumen (FL) patient, accelerates aortic expansion and, eventually, necessitates aortic reintervention. The study compares aortic wall remodelling following standard hemiarch repair to that following a novel extended arch repair stent (AMDS) in Debakey I dissections. All patients who received hemiarch repair or hemiarch repair plus an uncovered arch dissection stent (AMDS) for Debakey I ATAAD between 2017-2021 at two Canadian centers were included. Patients were excluded if they received an extended arch repair. Baseline, intra- and post-operative characteristics were collected. All available pre- and post-operative CT scans were analyzed for presence of DANE, aortic wall dimensions, and FL patency along aortic length. The primary outcome measures were the incidence of DANE, positive aortic remodeling, mortality, and aortic reintervention rates at last follow-up. A total of 114 patients underwent repair for Debakey I ATAAD with either an isolated hemiarch (n=77; f/u for 157 days) or hemiarch plus an AMDS (n=34; f/u for 159 days). The groups did not have significant differences in baseline characteristics. Intraoperatively, the AMDS group were more likely to receive unilateral antegrade cerebral perfusion (p = 0.015) with axillary cannulation (p = 0.03) and experienced longer cerebral perfusion and shorter cerebral ischemia times (p = 0.03 and p = 0.011, respectively), compared to the isolated hemiarch cases. During follow-up, DANE occurred in 43.3% of the isolated hemiarch group and 11.8% of the hemiarch plus AMDS group (p=0.002). The maximum aortic diameter did not differ between the two groups, but the incidence of FL thrombosis and obliteration favored the AMDS group in the aortic arch (p=0.029), the proximal descending thoracic aorta (p=0.031) and at the level of pulmonary artery bifurcation (p=0.044). Mortality and in-hospital adverse events were similar between the two groups. Although not statistically significant, there was a 3.9% incidence of reintervention for malperfusion for the isolated hemiarch group and 0% in the AMDS group (p = 0.552). Conclusion: The novel AMDS stent was associated with reduced incidence of DANE at the time of hemiarch repair and promoted positive aortic wall remodeling thereafter through FL thrombosis and obliteration. Further follow-up is necessary to assess its impact on long-term aortic remodeling and morbidity/mortality.