SAN FRANCISCO – The occlusion of at least one collateral bed was a significant predictor of immediate-onset spinal cord ischemia and reduced the chances of recovery and survival from the condition, results from a prospective study demonstrated.
"Endovascular aortic repair, particularly thoracoabdominal aortic aneurysm repair, mandates the occlusion of important collateral network vessels, specifically the intercostal and lumbar arteries," Dr. Matthew J. Eagleton said at Society for Vascular Surgery Annual Meeting. "Occlusion of at least one other collateral network vessel, whether that’s the hypogastric artery or the subclavian artery, is associated with early onset SCI, reduced recovery from SCI, and reduced survival."
Dr. Eagleton of the department of vascular surgery at the Cleveland Clinic, described spinal cord ischemia (SCI) as "a devastating complication after aortic surgery. In the past, much effort has been directed toward understanding the pathophysiology of spinal cord ischemia development, developing preventive strategies, and developing treatment strategies."
Endovascular aortic surgery "changes our approach to aortic disease," he continued. "While it offers a potentially less invasive option, there are some caveats to that when it comes to SCI. In many instances, especially in extensive aneurysms, we are unable to preserve important intercostal and lumbar arteries. In comparison to open surgery, we don’t know if spinal cord ischemia develops at the same rate, for the same reasons, with similar presentations and clinical course, or whether our current preventive and treatment algorithms are applicable in this patient population."
In an effort to evaluate factors affecting outcomes from SCI associated with endovascular aortic aneurysm repair, Dr. Eagleton and his associates evaluated 1,251 patients enrolled in three physician-sponsored investigational device exemption (IDE) trials from 1998 to 2010. They identified patients with confirmed SCI, reviewed their medical records and imaging studies, and used these to supplement prospectively collected data. Outcome measures included the timing of onset of SCI, recovery from SCI, and survival.
In all, 1,251 patients were treated with aortic endografts. Of these, 351 (28%) were infrarenal endografts, 201 (16%) were thoracic endografts, 227 (18%) were fenestrated endografts, and 472 (38%) were visceral branch grafts.
Dr. Eagleton and his associates identified 36 patients with SCI, for a rate of 2.9%. Their mean age was 73 years and 72% were male. The mean aneurysm size in SCI patients was 65 mm; 47% had undergone prior aortic surgery, predominately repair of an infrarenal AAA; and 25% required a conduit. The majority of conduits (78%) were placed at the time of endograft placement while the remainder were placed on an elective basis. The mean percentage length of aorta covered was 67%.
A total of 11 patients (31%) with SCI had at least one occluded collateral vessel. The majority of patients presented with either a motor deficit or a motor and sensory deficit (44% and 47%, respectively). Nearly three-quarters of SCI symptoms (72%) were bilateral in nature.
Onset of symptoms ranged from 0 to 240 hours. Immediate onset occurred in 42% of patients, with delayed onset in the remaining 58%. The one clinical factor that was significantly associated with immediate onset of SCI was the occlusion of at least one collateral bed (P = .021).
During a mean follow-up of 22 months, 30-day survival was 92%, 1-year survival was 56%, and 3-year survival was 45%. Survival was significantly reduced in patients who did not recover from their symptoms of SCI.
The relatively small size of the study cohort "limits extensive statistical analysis," Dr. Eagleton said. "The retrospective nature of clinical data limits more detailed information about clinical presentation and it provides little information about why these patients developed SCI as compared to their counterparts. This will certainly require a more focused evaluation of those who are at higher risk for the development of SCI."
In the meantime, he said, "aggressive efforts need to be made to maintain all collateral flow possible and prevent perioperative complications that diminish spinal cord perfusion. We need to evaluate other methods to augment these preventive strategies."
Dr. Eagleton disclosed that he is a consultant for Bolton Medical and Cook Medical.