The “bare branch” for safe spinal cord ischemia prevention after total endovascular repair of thoracoabdominal aneurysms

Objective: Staged endovascular treatment of thoracoabdominal aortic aneurysms (TAAAs) with temporary perfusion of the sac through a branch left unstented or a dedicated branch is a strategy intended to reduce the risk of postoperative spinal cord ischemia (SCI). However, potential complications of this approach are aneurysm sac progression between stages, visceral embolism, and occlusion or displacement of components. We here present the “bare branch” technique, a safe adjunct to TAAA repair in terms of interstage complications. Methods: In the first step, one branch, preferentially the one for the celiac trunk, is stented by a bare stent; in the second step, the bare branch is relined with a covered stent. There were 32 TAAAs (5 type I, 6 type II, 16 type III, 5 type IV) treated by this approach at our center from January 2015 to December 2017 (median follow-up, 13 months [range, 2-24 months]). Data were prospectively collected and retrospectively analyzed. Primary end points were aneurysm sac exclusion and freedom from major adverse events, which included SCI. Secondary end points were freedom from aneurysm growth between the stages and freedom from minor adverse events. Results: Preoperative mean maximum diameter was 68.4 mm; 32 endografts (8 off-the-shelf and 24 custom-made devices) were used. The mean aortic coverage was 364 mm. The mean interval time between the two stages was 10.5 weeks (range, 7-20 weeks). In-hospital mortality was 0%. Type I or type III endoleak rate was 3.2%, whereas one type II endoleak was registered (3.2%). Two patients showed paraparesis, one after the first stage and one after the second stage, both noted at 4/5 on the Tarlov scale, and fully recovered so that the SCI rate was 6.4% with 0% permanent neurologic deficit. Interstage mean maximum diameter was 68.6 mm (P > .05). After the second step, there was an average of 4.7 spinal arteries (standard deviation, 1.4; P < .05) per patient with an increase in visibility and of diameter by 0.7 mm (standard deviation, 0.4 mm). Conclusions: This is a reproducible adjunct to staged TAAA endovascular repair. The use of a bare branch instead of a branch left completely open has the clear advantage of an easy catheterization in the second step. Furthermore, by having the target vessel stented with a bare stent, the risk of embolism is avoided. In this experience, there was no significant aneurysm sac growth in between the steps. Further comparative studies may determine whether there are different hemodynamic forces with this technique with respect to those already described in the literature.