Single-Site Review of Spinal Cord Protection Protocols Including the Utilization of Spinal Drains versus Medical Management with Branched Endovascular Aortic Repair

Abstract

Spinal cord ischemia (SCI) continues to be a devastating complication after repair of thoracoabdominal aortic aneurysms. The objective of this review is to present our single-center outcomes after the implementation of a standardized neuroprotective protocol following branched endovascular aortic repair. A standardized neuroprotective protocol including preoperative steroids, acetazolamide, intraoperative hemodynamic parameters, and postoperative treatment goals was initiated in November 2019. Physician-modified branched endovascular repairs were completed at a single center from 2012 to 2021 with outcomes reviewed both before (n=107) and after (n=67) the implementation of the neuroprotective protocol. The primary end point was the incidence of any SCI event at 30 days. Secondary end points included all-cause mortality, stroke, myocardial infarction, and renal failure at 30 days. Patients with Crawford extents I-III, renal failure, or necessitating emergent repair were deemed high risk for SCI events and underwent a subset analysis. Survivability after SCI was estimated using Kaplan-Meier tables. Of the 174 consecutive patients treated, the 67 patients treated following implementation of the neuroprotective protocol were more likely to have experienced a prior myocardial infarction (26.9% vs. 14%; P=0.0466) and have a history of chronic obstructive pulmonary disease (64.3% vs. 45.8%; P=0.02). This group was more likely to be treated for paravisceral aneurysms (53.7% vs. 24.3%; P=0.0002). Postprotocol implementation, spinal drain use was lower (6% vs. 38.3%; P = <0.0001) with 100% of these drains placed in urgent or unstaged thoracoabdominal aortic aneurysm repairs as a part of the protocol. Rates of any SCI event among all patients before and after implementation of the protocol were 9.3% (n=10 of 107) and 6% (n=4 of 67; P=0.57), respectively. In comparison, the protocol significantly reduced SCI rates to 0 (0% vs. 17.1%; P=0.0407) in high-risk patients. Frequency of renal failure was reduced (3% vs. 14%; P=0.018) after initiation of the protocol. Patients in the postprotocol group had significantly improved 1-year mortality rate (9% vs. 27.1%; P=0.0035) and renal failure rates (2% vs. 15%; P=0.018). Regression models indicated that patients in the postprotocol group had lower likelihood of mortality and renal failure than patients in preprotocol group (P<0.05) and that spinal drain reduced mortality (P<0.1). Implementation of a standardized neuroprotective protocol that focuses on medical management and fluid dynamics may significantly reduce risk of SCI after branched endovascular repairs, with the most significant improvement of SCI outcomes involving those at greatest risk for developing SCI. Also noteworthy, there was significant improvement to 1-year survivability after the implementation of this neuroprotective protocol.