Spinal Cord Ischaemia in Endovascular Thoracic and Thoraco-abdominal Aortic Repair: Review of Preventive Strategies

Abstract

Introduction: The incidence of spinal cord ischaemia (SCI) and subsequent paraplegia after thoracic endovascular aneurysm repair (TEVAR) and thoraco-abdominal endovascular aneurysm repair is estimated to be between 2.5% and 8%. The aim of this review is to provide an overview of SCI preventive strategies in TEVAR and thoraco-abdominal repair and recommend an optimal strategy. Methods: Medline, Embase, and the Cochrane Library were searched for studies on TEVAR, thoraco-abdominal endovascular repair, and the use of SCI preventive measures. The review was reported according to the PRISMA statement. Results: The final analysis included 43 studies (7168 patients). All studies are cohort studies (non-comparative cohorts n = 37, comparative cohorts n = 6) and largely performed retrospectively (n = 27). The included studies had an average MINORS score of 9 (range 6-13) for non-comparative studies and 15.5 (range 12-18) for comparative studies. Transient SCI occurred in 5.7% (450/7,168, 95% CI 4.5-6.9%), permanent SCI in 2.2% (232/7,168, 95% CI 1.6-2.8%). There was a trend towards increased SCI incidence for more "high risk" cohorts. Avoidance of hypotension resulted in a slightly lower permanent SCI rate 1.8% (102/4216, 95% CI 1.2-2.3%) than the overall cohort. A very low SCI estimate (transient and permanent) was found in the subgroup of studies (2 studies, n = 248) using (mild) peri-operative hypothermia (transient SCI 0.8%, permanent SCI 0.4%). In the subgroup using temporary permissive endoleak, there was a transient SCI estimate (15.4%), with a permanent SCI estimate of 4.8%. The remaining preventive measures did not significantly impact transient or permanent SCI estimates. Conclusion: Low overall transient and permanent SCI rates are achieved during endovascular thoracic and thoraco-abdominal aortic repair. Based on the presented data, the use of selective spinal fluid drainage in high risk patients seems justified. Peri-operative hypotension should be avoided and treated where possible. The use of mild hypothermia is promising in small cohorts, but requires further evaluation. Further high quality data are essential to establish a definitive preventive strategy.