IYSC01 - Morphology of True Lumen and Surgical Outcomes of Acute Type A Aortic Dissection Repair with Visceral Malperfusion

Objectives: Acute type A aortic dissection (ATAD) can cause visceral malperfusion. Many of the malperfusion resolves with central aortic repair but some require further visceral intervention. This study aimed to review outcomes after ATAD presenting with visceral malperfusion and to evaluate for predictive value of true lumen morphologies in preoperative computed tomography (CT) for persistent visceral ischemia after central repair.

Methods: Open surgical repair of ATAD performed between 2008 and 2023 at our institution was retrospectively reviewed. Patients with central repair first approach were included for analysis. Patients with inadequate CT scan data to assess luminal morphology were excluded. Cases were categorized as having concave (crescent) or convex (lens) based on the true lumen morphology at the diaphragm level, and were also assessed for the ischemia pattern (dynamic vs. static) at the celiac axis and superior mesenteric artery (SMA) orifices. Data were analyzed by contingency table, parametric and nonparametric methods.

Results: A total of 543 open repairs were performed. Of these, 267 patients were deemed eligible under the inclusion criteria and subsequently analyzed. The mean age was 57 ± 14, and 83 (31%) patients were female. SMA malperfusion developed in 49 (18%) of the 267 patients. Regarding dissection flap morphology, 80 patients (30%) exhibited concave morphology, while 187 patients (70%) had convex morphology. True lumen diameter was significantly larger in convex than concave (16 mm vs. 6 mm, p< 0.0001). False lumen was more likely to have thrombosed in the convex group (28% vs. 6%, p< 0.0001).
The prevalence of clinically significant visceral malperfusion was higher in concave true lumen (SMA, 48% vs. 6%, p< 0.0001; celiac axis, 41% vs. 4%, p< 0.025). Dynamic SMA obstruction was more frequently observed in the concave group (78% vs. 33%, P =0.0047). However, significantly more patients with convex shaped true lumen required bowel resection compared with patients with concave morphology (29% vs. 82%, p=0.0015). The 30-day mortality was not different between morphology types (concave 21% vs. convex 36% , p=0.298).

Conclusions: Central repair first strategy could resolve more than 70% of visceral malperfusion in ATAD when true lumen is concave at the level of the diaphragm. Convex true lumen morphology was associated with less incidence of visceral malperfusion, but it had more static obstruction and required bowel resection. The morphology evaluation of the true lumen at the diaphragm level may be a simple and beneficial method for planning approach in treating ATAD presenting with visceral malperfusion.