Posterior False Lumen and Paraplegia After FET Procedure in Acute Type A Aortic Dissection.

Background: Postoperative paraplegia is the major concern with the frozen elephant trunk (FET) procedure in patients with acute type A aortic dissection (ATAAD). It is crucial to identify patients with a high risk of paraplegia before implementing the FET procedure.

Methods: From January 2013 to December 2018, 544 patients with ATAAD who underwent FET procedures were included in this study. The segment number of posterior false lumens (PFLs) between T9 and L2 levels was calculated. In-hospital outcomes and long-term survival were investigated on the basis of the number of PFLs.

Results: The average age was 46.5 ± 9.9 years, and the proportion of female patients was 19.5% in this cohort. The incidence of postoperative paraplegia was significantly increased when PFL was present in 3 or more segments. Patients were divided into a high-PFL group (3-6 segments; n = 124) and a low-PFL group (0-2 segments; n = 420). The demographic characteristics were similar between the 2 groups. Involvement of the celiac trunk and the superior mesenteric artery was significantly lower in the high-PFL group (all P < .05). The other baseline characteristics and procedural information were statistically balanced. The incidence of postoperative paraplegia was significantly higher in the high-PHL group (7.3% vs 1.9;P = .006). Multivariable logistic analysis revealed that high PFL was independently associated with postoperative paraplegia after an FET procedure (odds ratio, 3.812; 95% CI, 1.378-10.550; P = .010). Additionally, the moderate nasopharyngeal temperature of hypothermic circulatory arrest (≧23.0 °C) was clarified as a protective factor for paraplegia (odds ratio, 0.112; 95% CI, 0.023-0.535; P = .006).

Conclusions: Patients with ATAAD who present with high PFL between T9 and L2 levels have a significantly high risk of postoperative paraplegia if they undergo an FET procedure.