Background: Hemiarch replacement (HAR) represents the standard surgical treatment for acute type A aortic dissection (ATAAD) in patients with an intact intimal layer, without a tear at the dissected arch level. Nevertheless, the distal anastomosis represents the weak point of this procedure since a distal anastomotic new entry tear (DANE) may occur. The new developed non-covered hybrid AMDS stent (Ascyrus Medical, Frankfurt, Germany) provides a possible solution of this issue, enabling a stabilization of the aortic wall layers due to its radial forces. Aim of this study was to compare the peri- and early postoperative results of this new hybrid procedure with the standard HAR in terms of mortality, stroke and early aortic remodeling.
Method: From a total number of 125 consecutive patients with ATAAD treated between 12/2010 and 06/2021 in our unit, a cohort of n = 50 HAR patients was selected, with no preoperative stroke and no malperfusion, who presented an intact intimal layer at the open arch inspection. Peri- and early postoperative data of these patients were than compared with a recent group of n = 7 patients with similar pathology treated with the AMDS hybrid stent. Primary end points were: 30-day mortality, stroke, spinal cord ischemia, malperfusion and evidence of an early aortic remodeling.
Results: The groups were equal in terms of age (65 ± 14 vs. 61 ± 15 years), EuroSCORE II (18 ± 15 vs. 17 ± 13), GERAADA score (18 ± 12 vs. 18 ± 7) and comorbidities. Bentall procedure was performed more often in the HAR cohort (44 vs. 29%). Cardiopulmonary bypass (246 ± 71 vs. 225 ± 44 minute), hypothermic circulatory arrest (44 ± 23 vs. 55 ± 18 minute) and selective cerebral perfusion times (42 ± 24 vs. 50 ± 19 minute) were similar in both groups. AMDS patients had a shorter ventilation time (1.1 ± 0.4 vs. 2.2 ± 3.3 days) and intensive care stay (4.9 ± 5.0 vs. 6.7 ± 6.3). 30-day mortality (0 vs. 16), stroke (0 vs. 10%), spinal cord ischemia (0 vs. 2%) and malperfusion rate (0 vs. 8%) were lower in the AMDS group. Postoperative day five angiographic computed tomography revealed evidence of an early aortic remodeling at the arch level, with proximal occlusion of the false lumen in only 43% following AMDS.
Conclusion: If the tissue structure permits, the endovascular arch stabilization using the hybrid AMDS stent offers a safe alternative to HAR, though with excellent early results. The early remodeling seems to depend on the aortic arch and descending aorta anatomy and is not seen in every patient.
