National incidence, mortality outcomes, and predictors of spinal cord ischemia after thoracic endovascular aortic repair.

OBJECTIVE

Spinal cord ischemia (SCI) is a dreaded complication of thoracic endovascular aortic repair (TEVAR). There are limited national data describing the incidence and influence of in-hospital SCI recovery on survival. Moreover, no robust preoperative SCI risk assessment models currently exist. The purpose of this analysis was to analyze the Vascular Quality Initiative to determine the national incidence, survival association, and preoperative predictors of SCI after TEVAR.

METHODS

All Vascular Quality Initiative TEVAR procedures (June 2014-June 2019) were reviewed. The primary end point was development of in-hospital SCI, defined as any new neurologic deficit or paralysis not attributable to intracranial disease. Secondary end points were disease-specific SCI rates and long-term out-of-hospital survival. Functional outcomes (transient vs permanent SCI) were independently determined by treating physicians. Kaplan-Meier analysis and Cox proportional hazards methodology were used to assess the association of SCI with survival. A logistic regression model of candidate preoperative SCI predictors was created, and bootstrapped backward elimination (retaining predictors with ≥50% selection frequency) was used for model reduction. Model fit and performance statistics were validated by adjustment for Efron's optimism.

RESULTS

The overall rate of SCI was 3.7% (n = 422/11,473; transient, 1.6% [n = 179]; permanent, 2.1% [n = 243]). Patients who developed any SCI had significantly lower Kaplan-Meier survival estimate compared with those without SCI (1-year survival: SCI, 65%; no SCI, 87%; P < .0001), and patients with permanent SCI had notably worse survival than patients with transient SCI (1-year survival: permanent SCI, 54%; transient SCI, 80%; P < .0001). Disease-specific incidence of any SCI was as follows: aneurysm, 3.4%; dissection, 5.3%; aneurysm from dissection, 4.1%; trauma, 1.1%; penetrating ulceration, 2.4%; intramural hematoma, 5.7%; penetrating ulceration and intramural hematoma, 4.3%; and aortic thrombus, 4.8%. Several factors were selected on multivariable analysis as the most robust preoperative predictors of any SCI, including distal landing zone 5 to zone 10, nonelective case, creatinine concentration >1.38 mg/dL, smoking history, American Society of Anesthesiologists class, adjunctive procedure, nonwhite race, and preoperative hypertension (area under the curve = 0.72; Nagelkerke R = 0.06).

CONCLUSIONS

SCI is a devastating complication after TEVAR that is associated with worse overall survival, particularly when no functional recovery occurs by hospital discharge. Disease-specific, real-world benchmarks for SCI rates are provided that may inform quality initiatives focused on reducing this complication. Importantly, this analysis is the first description of a preoperative prediction model derived from national data for determining SCI risk after TEVAR. These predictors should be used to identify high-risk patients to balance the risk of SCI and its associated increased short-term mortality with the risk of the underlying disease. Furthermore, all available adjunctive measures should be implemented in these high-risk patients to reduce risk of SCI.