Neuromonitor-guided repair of thoracoabdominal aortic aneurysms

[Intraoperative electrophysiological monitoring with evoked potentials]

During the last 30 years intraoperative electrophysiological monitoring (IOEM) has gained increasing importance in monitoring the function of neuronal structures and the intraoperative detection of impending new neurological deficits. The use of IOEM could reduce the incidence of postoperative neurological deficits after various surgical procedures. Motor evoked potentials (MEP) seem to be superior to other methods for many indications regarding monitoring of the central nervous system. During the application of IOEM general anesthesia should be provided by total intravenous anesthesia with propofol with an emphasis on a continuous high opioid dosage. When intraoperative MEP or electromyography guidance is planned, muscle relaxation must be either completely omitted or maintained in a titrated dose range in a steady state. The IOEM can be performed by surgeons, neurologists and neurophysiologists or increasingly more by anesthesiologists. However, to guarantee a safe application and interpretation, sufficient knowledge of the effects of the surgical procedure and pharmacological and physiological influences on the neurophysiological findings are indispensable.

Thromboendarterectomy and circulatory arrest

Thromboendarterectomy remains a high-risk procedure. The use of circulatory arrest as a technique to allow pulmonary artery visualization is associated with cerebral and organ damage secondary to the ischaemic insult. Application of techniques learned from thoracic aortic stenting and minimal invasive valvular surgery may mean that circulatory arrest becomes an uncommon accompaniment to thromboendarterectomy.

Endovascular approaches and perioperative considerations in acute aortic dissection

Aortic dissections remain complicated management issues both in the acute setting and in the chronic setting. Acute problems revolve around malperfusion syndromes or rupture, whereas chronic issues progress from the development of aneurysms in the residual dissected aorta. Endovascular approaches to dealing with these difficult situations are being used more frequently to treat acute issues in type B dissections and prevent secondary complications in type A dissections that may require significant intervention in the future. This article discusses the endovascular approaches employed in the care of acute dissections with particular attention toward the anesthetic considerations involved in these challenging cases.

Neurological complications of thoracic endovascular aortic repair

Thoracic endovascular aortic repair (TEVAR) has decreased the morbidity and mortality associated with open surgical repair of descending thoracic aortic diseases, but important complications unique to the procedure remain. Spinal cord ischemia and infarction is a recognized complication caused by endovascular coverage or injury to spinal cord collateral vessels. Stroke is a consequence of thromboembolism or coverage of aortic arch branch vessels with insufficient collateral circulation. Understanding the risk factors and the pathophysiology of neurological complications of TEVAR are important for the successful anesthetic and surgical management and treatment of patients undergoing endovascular procedures involving the thoracic aorta.