Abstract TP126: Intraoperative Neurophysiological Monitoring in Carotid Endarterectomy: An Analysis of the Nationwide Inpatient Sample

Abstract

Introduction: Carotid endarterectomy (CEA) is an effective treatment for symptomatic carotid stenosis (CS) but the ischemic complications of the procedure can be detrimental. Intraoperative neurophysiological monitoring (IONM) is used to protect neural structures during surgery. The incidence, predictors, and in-hospital outcomes associated with the use of IONM in CEA have not previously been reported. Methods: The Nationwide Inpatient Sample from 2007 to 2011 was queried to identify cases of CEA procedures (ICD-9-CM code 38.12) accompanied by occlusion or stenosis of the precerebral arteries (ICD-9-CM codes 433.10-1). Independent predictors of IONM utilization (ICD-9-CM code 00.94), perioperative/postoperative stroke, prolonged length of stay (LOS; defined as ≥ 75th percentile), increased hospital costs (defined as ≥ 75th percentile), and in-hospital mortality were identified using multivariable logistic regression analyses. Results: A total of 518,685 CEA procedures for CS were identified. The utilization of IONM (0.74%) increased from 0.06% in 2007 to 1.74% in 2011 (P<0.0001). Multivariate predictors of IONM, adjusted for demographics, hospital characteristics, comorbidities, and presentation of symptoms, included increasing comorbidity score (OR: 1.045, 95% CI: 1.01-1.08, P=0.004), African American race (OR: 1.59, 95% CI: 1.36-1.85, P<0.0001), Medicaid status (OR: 1.35, 95% CI: 1.11-1.63, P<0.0001), large hospital bed size (OR: 3.70, 95% CI: 3.03-4.51, P<0.0001), urban location (OR: 4.97, 95% CI: 3.50-4.51, P<0.0001), teaching hospital status (OR: 3.56, 95% CI: 3.24-3.91, P<0.0001) and weekend admission (OR: 1.25, 95% CI: 1.04-1.49, P=0.015). The utilization of IONM decreased the likelihood of perioperative/postoperative stroke (OR: 0.61, 95% CI: 0.38-0.97, P=0.036) and in-hospital mortality (OR: 0.37, 95% CI: 0.15-0.89, P=0.027). The use of IONM increased the likelihood of prolonged LOS (OR: 1.21, 95% CI: 1.72-2.28, P<0.0001) and total hospital costs (OR: 1.98, 95% CI: 1.72-2.28, P<0.0001). Conclusion: The use of IONM in CEA has increased over time. The utilization of IONM was shown to decrease perioperative/postoperative stroke and in-hospital mortality rates while increasing LOS and hospital costs.