Neurologic Complications after Open and Endovascular Aortic Surgery



Neurologic Complications after Open and Endovascular Aortic Surgery



Richard M. Green


Neurologic complications after aortic surgery can range from minor irritants to life-threatening problems. It is important to recognize that the majority, but certainly not all, can be avoided by careful preoperative planning and meticulous intraoperative technique.



Spinal Cord Injury


The devastating neurologic injury following aortic surgery is spinal cord ischemia (SCI). This is true for open and endovascular procedures on the abdominal or thoracic aorta. Much has been written on the cause and avoidance of SCI after operations on the thoracic and thoracoabdominal aorta, and outcomes have improved since the 1980s. The ultimate risk depends on the presentation, the extent of aortic involvement and replacement, kidney function, and the experience of the surgical team.


Among other variables, cerebrospinal fluid (CSF) drainage and distal aortic perfusion are considered important technical adjuncts by a number of surgeons with extensive experience in this area. These techniques as well as others, such as spinal cord cooling, sequential aortic clamping, and reimplantation of intercostal arteries, all increase the tolerance of the spinal cord to clamp-induced ischemia. A nonrandomized but representative series by Safi and his colleagues comparing patients with CSF drainage and distal aortic perfusion against a group of patients without demonstrated a significantly lower neurologic complication rate (9% vs. 19%).


Intraoperative spinal cord monitoring is used in some centers to predict whether intercostal artery reimplantation is necessary. Loss of somatosensory evoked potentials within 15 minutes of aortic cross clamping indicates poor collateralization and mandates prompt restoration of spinal cord blood supply. This can improve with release of the proximal clamp or can require reimplantation of the intercostal arteries.


While the broad range of thoracic aortic pathologies are not currently treated with endografts (TEVAR), our limited experience indicates that paraplegia following thoracic endovascular aneurysm repair (TEVAR) ranges from 1.2% to 12.5%. There are two studies that compare the incidence of spinal cord ischemia after TEVAR and open repair. One of the two studies showed a reduction in SCI after TEVAR to 3%, as compared to 14% after open repair. Whether or not TEVAR provides protection against SCI is an unresolved issue. The difficulty in resolving this issue largely relates to the heterogeneity of the cohorts with regard to the extent of the aorta treated and clinical presentation.


In the EUROSTAR (EUROpean Collaboration on Stent/graft Techniques for Aortic aneurysm Repair) series, in the group of patients with SCI following TEVAR, 40% had the left subclavian artery (LSA) covered without revascularization, and 19% underwent preoperative revascularization. Multivariate analysis of the European experience determined that four factors are associated with paraplegia: coverage of the LSA without revascularization, kidney failure, prior or concomitant open abdominal aortic surgery, and three or more stent grafts used, indicating the amount of aortic coverage. The area around T10 appears to be most susceptible to SCI.


A review and meta-analysis of 51 observational TEVAR studies was performed under the aegis of the Committee on Thoracic Aortic Disease from the Society for Vascular Surgery to evaluate the outcome of LSA coverage. The findings documented that LSA coverage without revascularization was associated with a significant increase in arm ischemia (odds ratio [OR], 47.69) and vertebrobasilar insufficiency (OR, 10.78). There was a strong trend but an insignificant increase in SCI and anterior circulation stroke. As a result, the SVS has put forward three recommendations with regard to TEVAR and the LSA:



The LSA is not the only important source of arterial perfusion of the spinal cord. The alarming sevenfold increase in SCI after prior abdominal aortic aneurysm repair indicates the importance of the lumbar arteries in spinal cord perfusion. Other factors of significance in this analysis by Schlosser and coworkers are preoperative renal insufficiency (OR, 29.5), increase in length of aortic coverage (OR, 1.1 per centimeter increase), and the time interval between TEVAR and infrarenal repair (OR, 1.2 per year increase). Although the benefit of CSF drainage is not as clear with endovascular repair as it is with open repair, most experts recommend drainage when long segments of the aorta are covered and particularly when the area around T10 is involved.


The guidelines from the Society for Vascular Surgery recommend, regardless of technique (open vs. EVAR), that blood be preserved to at least one hypogastric artery. Failure to do so can result in pelvic ischemia, colonic ischemia, or spinal cord ischemia. Perfusion of the distal spinal cord is derived from the hypogastric artery via the lumbar, iliolumbar, and lateral sacral arteries. These vessels become significant when perfusion from the greater radicular artery is compromised or eliminated by coverage by an endograft.

Related posts:

  1. Technical Aspects of Percutaneous Carotid Angioplasty and Stenting for Arteriosclerotic Disease
  2. In-Situ Treatment of Aortic Graft Infection with Prosthetic Grafts and Allografts
  3. Treatment of Acute Upper Extremity Venous Occlusion
  4. Intraoperative Assessment of the Technical Adequacy of Carotid Endarterectomy

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Aug 25, 2016 | Posted by in CARDIOLOGY | Comments Off on Neurologic Complications after Open and Endovascular Aortic Surgery

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