Minimally Invasive Segmental Artery Coil Embolization Before Endovascular Thoracoabdominal Aortic Aneurysm Repair

Purpose: MISACE is a novel approach to reduce paraplegia risk in thoracoabdominal aortic aneurysm (TAAA) repair. Limited data exist to date, awaiting clinical trial results. We report our experience with MISACE as a method of spinal cord preconditioning to prevent spinal cord ischemia (SCI) after endovascular repair of TAAA.

Materials and Methods: Retrospective analysis was done of 17 patients who had an attempted MISACE before endovascular TAAA repair with follow-up to 2.4 years. Baseline patient and aneurysm characteristics along with procedural technique and outcomes were analyzed.

Results: The mean patient age was 69 years, and 76.5% were men. The majority of TAAA Crawford classification were type II (n = 6, 35.3%), type III (n = 4, 23.5%) and type IV (n = 5, 29.4%).The mean aortic diameter was 70.6 ± 10.9 mm. All aneurysms were degenerative, and 4 patients (23.5%) had an associated chronic type B dissection. Staged repair occurred in 9 patients (53%).On pre-embolization CT, the mean number of segmental arteries larger than 2 mm was 3.8 ± 2.9. Technically successful embolization occurred in 14 patients (82.4%) and was unsuccessful in 3 patients (17.6%). The median number of embolized arteries was 3 (range, 1–6), and most of the target arteries were between the T9 and T12 levels (29 of 41 vessels, 71%). Mean procedure fluoroscopy time was 51.5 ± 22.5 minutes, and the mean contrast volume used was 132.8 ± 56.1 mL. The average number of catheters used was 4.6 (range, 2–8) and 3.5 wires (range, 2–6). No complications were related to the procedure. Mean interval between embolization to endovascular TAAA repair was 51.2 days (5–110 days). All patients received spinal drainage at the time of repair. Postoperatively, SCI occurred in 3 patients (17.6%). The single case of permanent paraplegia had a failed embolization attempt, and SCI developed secondary to an episode of flash pulmonary edema (>48 hours postoperatively) that required intubation and dialysis. The second SCI occurred after two of the three segmental arteries were successfully embolized. This patient had early paraplegia treated with endoleak creation, hyperbaric oxygen therapy, and spinal drainage. The patient recovered to ambulate but had permanent bladder dysfunction. The third SCI case had paraparesis that was likely secondary to occlusion of bilateral internal iliac sandwich grafts but fully recovered.

Conclusions: MISACE before endovascular TAAA repair is a promising strategy to prevent SCI. Data thus far suggest this technique is feasible and safe but can be challenging secondary to anatomic features.