Near-infrared Spectroscopy Monitoring of the Collateral Network Prior to, During, and After Thoracoabdominal Aortic Repair: A Pilot Study

Objective: The aim of this study was to evaluate the feasibility of non-invasive monitoring of the paraspinous collateral network (CN) oxygenation prior to, during, and after thoracoabdominal aortic repair in a clinical series. Methods: Near-infrared spectroscopy optodes were positioned bilaterally over the thoracic and lumbar paraspinous vasculature to transcutaneously monitor muscle oxygenation of the CN in 20 patients (age: 66 10 years; men = 11) between September 2010 and April 2012; 15 had open thoracoabdominal aortic repair (Crawford II and III), three had thoracic endovascular aortic repair (TEVAR; Crawford l), and two had a hybrid repair (Crawford II). CN oxygenation was continuously recorded until 48 hours postoperatively. Results: Hospital mortality was 5% (n = 1), 15% suffered ischemic spinal cord injury (SCI). Mean thoracic CN oxygenation saturation was 75.5 8% prior to anesthesia (=baseline) without significant variations throughout the procedure (during non-pulsatile cooling on cardiopulmonary bypass and with aortic cross-clamping; range = 70.6-79.5%). Lumbar CN oxygenation (LbS) dropped significantly after proximal aortic cross-clamping to a minimum after 11.7 +/- 4 minutes (74 +/- 13% of baseline), but fully recovered after restoration of pulsatile flow to 98.5% of baseline. During TEVAR, stent-graft deployment did not significantly affect LbS. Three patients developed relevant SCI (paraplegia n = 1/paraparesis n = 2). In these patients LbS reduction after aortic cross-clamping was significantly lower compared with patients who did not experience SCI (p = .041). Conclusions: Non-invasive monitoring of CN oxygenation prior to, during, and after thoracoabdominal aortic repair is feasible. Lumbar CN oxygenation levels directly respond to compromise of aortic blood circulation. (C) 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.