Incidence, prevention, and management in spinal cord protection during TEVAR.

Until recently, patients with aneurysms of the thoracic and thoracoabdominal aorta had only one treatment option: open surgical repair. For those patients who could not tolerate an operation because of medical comorbidities, continued aneurysm enlargement and eventual rupture was a constant, yet unpredictable threat to their lives. Several studies have documented improved survival rates in those patients treated surgically. Despite advances in surgical reconstruction and organ protection, the mortality rate for elective surgical repair of thoracoabdominal aortic aneurysm is 4% to 21%; advanced age, renal failure, and postoperative paraplegia are the most important risk factors predicting death at 30 days. In addition, for those patients aged 79 with an emergency presentation, history of diabetes or congestive heart failure, 30-day mortality is 50%. For aneurysms isolated to the distal thoracic aorta, the risk of paraplegia is 0% to 4% and is dependent on the extent of aorta replaced. A substantial number of patients surviving the operation have prolonged, complicated courses secondary to renal, cardiac, and pulmonary dysfunction. Perhaps the most devastating complication of these complex procedures for patients and their surgeon is paraplegia. A myriad of techniques have been developed to protect the spinal cord during open surgical repair of the thoracic and thoracoabdominal aorta, including clamp-and-sew, distal aortic and visceral perfusion, complete cardiopulmonary bypass, profound hypothermia and circulatory arrest, direct spinal cord cooling, cerebrospinal fluid (CSF) drainage, and the use of pharmacologic adjuncts; some of these principles may be useful in preventing paraplegia at the time of endovascular repair. When the thoracic aorta is crossclamped, spinal arterial perfusion pressure decreases while CSF pressure increases, resulting in decreased perfusion pressure. In an important study of 1004 patients by Safi et al, immediate postoperative neurologic deficit occurred in 6.8% of patients operated on without the adjuncts of CSF