Emergency endovascular treatment for ruptured abdominal aortic aneurysm and the risk of spinal cord ischemia.

BACKGROUND

Spinal cord ischemia is a rare complication after open surgical repair for ruptured abdominal aortic aneurysms (rAAA). The use of emergency endovascular aortic aneurysm repair (eEVAR) is increasing, and paraplegia has been observed in a few patients. The objective of this study was to assess the incidence and pathogenesis of spinal cord ischemia after eEVAR in greater detail.

METHODS

This was a retrospective analysis of patients who had eEVAR for rAAA in three hospitals in The Netherlands and Belgium during a 3-year study period that ended in February 2004. The use of aortouniiliac devices combined with a femorofemoral crossover bypass was the preferred technique. Patients with postoperative symptoms of spinal cord ischemia were identified and the influence of potential risk factors was assessed. These factors included the presence of common iliac artery aneurysms necessitating device limb extension to the external iliac artery with associated overlapping the hypogastric artery, the prolonged interruption of bilateral hypogastric artery arterial inflow during the procedure (defined "functional aortic occlusion time" >30 minutes), and the occurrence of preoperative hemodynamic shock.

RESULTS

Thirty-five patients were treated by EVAR and they constituted the study group. The first-month mortality in the study group with EVAR was 23%. Four patients (11.5%) with EVAR developed paraplegia postoperatively; the unilateral or bilateral hypogastric artery in all four patients became occluded during the procedure. In the other 31 patients who did not have paraplegia, the unilateral or bilateral hypogastric arteries became occluded in 14 patients (45%). This constituted a significant difference in the prevalence of hypogastric artery occlusion in patients with or without paraplegia (P = .04). The functional aortic occlusion time was prolonged in all four patients with paraplegia and in five without spinal cord ischemia (P = .0003). All four patients with spinal cord ischemia presented with hemodynamic shock. This factor did not reach a significant difference from nonparaplegic patients.

CONCLUSION

Emergency EVAR continues to be a promising approach to reduce the high mortality of rAAA, but the incidence of spinal cord ischemia after endovascular treatment of rAAA was worrisome. Although the pathogenesis is most likely multifactorial, interruption of the hypogastric artery inflow appeared to have significant influence. In patients with aneurysmatic common iliac arteries, any effort should be made to minimize hypogastric occlusion time during the procedure and to maintain hypogastric artery inflow afterwards, either by the use of a bell-bottom iliac extension or by electing open repair.