Morphology of true lumen and surgical outcomes of acute type A aortic dissection repair with superior mesenteric artery malperfusion

Background: Acute type A aortic dissection (ATAD) can cause visceral malperfusion. Central aortic repair may resolve malperfusion, but some require further intervention. This study aimed to review outcomes after ATAD presenting with visceral malperfusion and to evaluate the predictive value of true lumen (TL) morphologies in preoperative computed tomography scan for persistent superior mesenteric artery (SMA) ischemia after central repair. Methods: Open surgical repair of ATAD performed between 2008 and 2023 at our institution was reviewed retrospectively. Patients with central repair first approach were included for analysis. Patients with inadequate computed tomography scan data to assess luminal morphology were excluded. TL morphology was reviewed at the diaphragm level and categorized as concave or convex. The malperfusion pattern, static vs dynamic, was assessed at SMA orifices. Data were analyzed using a contingency table and parametric and nonparametric methods. Results: A total of 543 open ATAD repairs were performed. Of these, 263 patients were eligible under the inclusion criteria and, subsequently, analyzed. The mean age was 57 +/- 14, and 83 (31%) patients were female. SMA malperfusion developed in 42 (16%) of the 263 patients, including 26 patients with dynamic obstruction, 6 patients with static obstruction, and 10 patients with dynamic and static obstruction. Regarding dissection flap morphology, 78 patients (30%) exhibited concave morphology, while 185 patients (70%) had convex morphology. TL diameter was significantly larger in convex than concave (concave: 6 mm vs convex: 16 mm; P < .0001). The prevalence of clinically significant SMA malperfusion was higher in concave-shaped TL (concave 41% vs convex 5%; P < .0001). Dynamic SMA obstruction was more frequently observed in the concave group (concave 72% vs convex 30%; P < .001). However, significantly more patients with convex-shaped TL required bowel resection than concave (concave 13% vs convex 70%; P < .001). The operative mortality was higher in the convex group, although statistically insignificant (concave 19% vs convex 50%; P = .0059). Conclusions: Central repair first strategy could resolve more than 80% of SMA malperfusion in ATAD when the TL is concave-shaped at the level of the diaphragm. Convex-shaped TL morphology was associated with less incidence of SMA malperfusion but was more frequently associated with static obstruction and higher incidence of bowel resection. The morphology evaluation of the TL at the diaphragm level may be simple and beneficial for surgical planning for ATAD presenting with SMA malperfusion.