A prevention protocol reduces spinal cord ischemia in patients undergoing branched/fenestrated endovascular aortic repair

Objective: Spinal cord ischemia (SCI) is a devastating complication that is associated with thoracoabdominal aortic repair, with higher risk associated with increased aortic coverage length, making patients undergoing branched/fenestrated endovascular repair (B/FEVAR) particularly vulnerable. A bundled SCI prevention protocol was previously reported to reduce SCI rates when compared to a historic cohort in a single-center study. Therefore, this analysis aims to further validate and update outcomes associated with the protocol given the routine implementation of this strategy at two institutions (University of Florida and the University of Alabama at Birmingham) since inception.

Methods: Components of the SCI prevention protocol include selective cerebrospinal fluid drainage, specified blood pressure parameters, transfusion goals, and selective pharmacologic adjuncts (naloxone, steroids). This protocol was routinely implemented in May 2015. Patients undergoing B/FEVAR from May 2015 to December 2022 constituted the post-protocol cohort (n = 402) and were compared with the pre-protocol cohort (n = 160; January 2010-April 2015). The primary outcome was SCI incidence, and subgroup analysis was conducted among patients deemed to be high-risk (Crawford extent I-III thoracoabdominal aneurysm dissection-related disease, prior aortic repair, coverage proximal to zone 5). Survival analysis was performed using Kaplan-Meier methodology.

Results: The pre- and post-protocol cohorts were demographically similar, although more post-protocol patients were American Society of Anesthesiology class IV (86.1% vs 55.0%; P < .001). Thoracoabdominal aneurysm was the most common indication in both groups. Cerebrospinal fluid drain placement was more common in the post-protocol group, particularly among high-risk patients. SCI occurred in 15.9% of pre-protocol patients vs 3.0% of post-protocol patients (P < .001). In high-risk patients, the pre- and post-protocol cohort SCI incidence was 23.2% vs 5.0%, respectively (P < .001). Thirty-day mortality was decreased in the post-protocol cohort (6.3% vs 2.2%; P = .02). Although the post-protocol group had a trend toward improved 1-year survival, this was not statistically significant (84.4% vs 88.3%; log-rank P = .35). Among patients with SCI, 1-year mortality was 28% and 33.3% in the pre- and post-protocol groups, respectively (P = .46).

Conclusions: Implementation of a bundled SCI prevention protocol significantly reduces SCI rates in patients undergoing B/FEVAR, which has now been validated at two institutions, with the most significant reductions occurring among high-risk patients. Although the overall 1-year mortality difference was not significantly different between the cohorts, the high mortality rates among patients with SCI highlights the importance of preventative measures.