Intraoperative neuroprotective interventions prevent spinal cord ischemia and injury in thoracic endovascular aortic repair

Abstract

Transient and permanent paraparesis and paraplegia (spinal cord injury [SCI]) are reported in up to 13% of patients undergoing thoracic endovascular aortic repair (TEVAR) for descending thoracic aortic aneurysm, thoracoabdominal aortic aneurysm, and thoracic aortic dissection. We hypothesize that aggressive intraoperative and postoperative neuroprotective interventions prevent or significantly reduce all SCI in TEVAR. Using a prospectively maintained, Institutional Review Board-approved database, we retrospectively reviewed all TEVARs performed in a university tertiary referral center from 2005 to 2014 to study the incidence of all transient and permanent lower extremity SCI. Only TEVARs for traumatic aortic tear were excluded. Arch debranching and carotid subclavian bypass were performed before TEVAR in patients with arch involvement. All patients had moderate systemic hypothermia (34°C), mean arterial pressure ≥90mm Hg, and hemoglobin ≥10g/dL. Patients received mannitol (12.5g), methylprednisolone (30mg/kg), and naloxone (1μg/kg/h). Patients in whom >12cm of aortic coverage was planned had spinal fluid drained to a pressure of<8mm Hg intraoperatively and postoperatively until normal leg strength was confirmed. The main outcome measure was transient or permanent SCI. One hundred fifty-five patients had TEVAR between 2005 and 2014. Mean age was 74years, and 56.1% were male. Descending thoracic aortic aneurysm was present in 91.6%, thoracoabdominal aortic aneurysm in 8.4%, and dissection in 28.8%. Presentation was acute in 42.5%. The procedure included carotid-subclavian bypass in 18.7% of patients. Seventy-two percent of patients had spinal fluid drainage. Mean aortic coverage was 25cm. Eighty-one percent of patients had >12 cm aortic coverage, and 49% had complete coverage of the thoracic aorta (coverage from subclavian to celiac artery). In-hospital mortality was 1.94%. Stroke occurred in 1.32% of patients. No patient had renal failure. SCI occurred in 0.65% (1 of 154) of patients. SCI in TEVAR can be significantly reduced by using proactive intraoperative and postoperative neuroprotective interventions that prolong spinal cord ischemic tolerance and increase spinal cord perfusion and oxygen delivery.