A Quantitative Assessment of the Impact of Intercostal Artery Reimplantation on Paralysis Risk in Thoracoabdominal Aortic Aneurysm Repair Discussions

Objectives: We previously demonstrated an 80% reduction in paraplegia risk using hypothermia, naloxone, steroids, spinal fluid drainage, intercostal ligation, and optimizing hemodynamic parameters. This report demonstrates that intercostal revascularization for the last 3 years further reduced our paraplegia risk index by 75%. Methods: We evaluated 655 patients who had thoracic or thoracoabdominal aneurysm repair for factors that affected paraplegia risk including aneurysm extent, acuity, cardiac function, blood pressure mean arterial pressure, and spinal fluid drainage with naloxone (SFDN). Eighteen patients died during or shortly after surgery leaving 637 patients for analysis of paralysis. We evaluated the effect of intercostal reimplantation (IRP) using a highly accurate (r > 0.88) paraplegia risk index we developed and published previously. Results: Fifty-eight percent of patients were male with a mean age of 67. Thirty-three percent were acute with rupture, acute dissection, mycotic aortitis, and trauma. Eighty (12%) had dissections. Thirty-five patients had paraplegia or paraparesis (5.4%). Significant factors by univariate analysis (P < 0.05) were Crawford type 2, acuity, SFDN, cardiac index after unclamping, mean arterial pressure during crossclamping, and IRP. In multivariate modeling, aneurysm extent, SFDN, acuity, and IRP remained significant (P < 0.02). The paraplegia risk index declined from 0.20 to 0.05 (P < 0.03). Conclusions: The incidence of paralysis after TAAA repair decreased from 4.83% to 0.88% and paralysis risk index decreased from 0.26 to 0.05 when intercostal artery reimplantation was added to neuroprotective strategies that had already substantially reduced paralysis risk. These findings suggest that factors that affect collateral blood flow and metabolism account for approximately 80% of paraplegia risk and intercostal blood flow accounts for 20% of risk. This suggests a limit to paraplegia risk reduction in thoracoabdominal endograft patients. Early results in this emerging field support this prediction of high paraplegia risk with thoracoabdominal branched endografts with extensive aortic coverage. Copyright © 2008 by Lippincott Williams & Wilkins.