PRELIMINARY-REPORT ON PREDICTION OF SPINAL-CORD ISCHEMIA IN ENDOVASCULAR STENT GRAFT REPAIR OF THORACIC AORTIC-ANEURYSM BY RETRIEVABLE STENT GRAFT

Objective: To predict spinal cord ischemia after endovascular stent gr aft repair of descending thoracic aortic aneurysms, temporary interrup tion of the intercostal arteries (including the aneurysm) was performe d by placement of a novel retrievable stent graft (Retriever) in the a orta under evoked spinal cord potential monitoring. Methods: From Febr uary 1995 to October 1997, endovascular stent graft repair of descendi ng thoracic aortic aneurysms was performed in 49 patients after inform ed consent was obtained. Ln 16 patients with aneurysms located in the middle and distal segment of the descending aorta, the Retriever was p laced temporarily before stent graft deployment. The Retriever consist ed of two units of self-expanding zigzag stents connected in tandem wi th stainless steel struts. Each strut was collected in a bundle fixed to a pushing rod, and the stent framework was lined with an expanded p olytetrafluoroethylene sheet. The Retriever was delivered beyond the a neurysm through a sheath and was retracted into the sheath 20 minutes later. A stent graft for permanent use was deployed in patients whose predeployment test results with the Retriever were favorable. Evoked s pinal cord potential was monitored throughout placement of the Retriev er and stent grafting until the next day. Results: The Retriever was p laced in 17 aneurysms in 16 patients. There were no changes in amplitu de or latency of evoked spinal cord potential records obtained before or during Retriever placement. After withdrawal of the Retriever, all aneurysms were excluded from circulation immediately after permanent s tent grafting. There were no changes in evoked spinal cord potential, nor were neurologic deficits seen after stent graft deployment in any patient. Conclusions: These results suggest that predeployment testing with the Retriever under evoked spinal cord potential monitoring is p romising as a predictor of spinal cord ischemia in candidates for sten t graft repair of thoracic aortic aneurysms.