Evaluation of visible spinal arteries on computed tomography angiography before and after branched stent graft repair for thoracoabdominal aortic aneurysm

Abstract

ObjectiveThe aim of this study was to evaluate the impact of intercostal and lumbar segmental arteries (SAs) detectable on computed tomography angiography (CTA) on the risk of spinal cord ischemia (SCI) in patients undergoing single-step or two-staged branched endovascular aneurysm repair (BEVAR). MethodsA retrospective analysis of patients treated with branched stent grafts for thoracoabdominal aortic aneurysm at a single institution from January 2009 to June 2015 was performed. Data including preoperative comorbidities, perioperative and aneurysm-related parameters, presence and type of endoleak, and rate of severe SCI at discharge or 30 days after the procedure were collected. Preoperative and postoperative contrast-enhanced CTA images were semiquantitatively analyzed by two independent investigators, and the number of visible SAs in the stented aorta before and after BEVAR was evaluated to find a possible correlation with severe SCI. ResultsSeventy-seven patients were treated for thoracoabdominal aortic aneurysm with BEVAR (47 men; mean age, 71.0 years), 40 (51.9%) of them with temporary aneurysm sac perfusion (TASP; open branch/TASP group) and 37 without (single-step group). The groups were comparable regarding parameters related to the patient, aneurysm type, and endovascular procedure. Severe SCI or paraplegia was observed in 10 patients (12.3%), and SCI was lower in the open branch/TASP group (2/40) compared with the single-step group (8/37; P = .032). The number of visible SAs in the intentionally overstented aortic segment was significantly reduced on postoperative CTA (10.0 vs 15.57 SAs; P < .001) in comparison to preoperative CTA imaging, with similar results in the open branch/TASP group (9.48 vs 15.83 SAs) and the single-step group (10.57 vs 15.30 SAs; P < .001 for both groups). Within the open branch/TASP group, more visible SAs were detected during the TASP interval in comparison to postoperative CTA after side branch completion (12.93 vs 9.48 SAs; P < .001). Receiver operating characteristic curve analysis in the single-step group revealed a cutoff point of 15 SAs on preoperative CTA with correlation to severe SCI (P = .006). In the high-risk subgroup of patients with 15 or more overstented SAs during BEVAR, staged open branch/TASP procedures again reduced the risk of SCI in comparison to the single-step patients (1/20 vs 8/22; P = .008). ConclusionsMore spinal arteries are visible during the TASP interval, supporting the open branch and TASP concept with a reduction of severe SCI during BEVAR. An intentional coverage of more than 15 SAs is related to an increased risk of SCI, and the rate of paraplegia was reduced after staged BEVAR with open branch/TASP in these high-risk patients.