SURGICAL TECHNIQUES : Aortic Arch and Deep Hypothermic Circulatory Arrest: Real-Life Suspended Animation - 08/09/11
Résumé |
Surgery of the aortic arch remains one of the great challenges facing thoracic surgeons. Despite continued advances in technique, bypass technology, and understanding of brain physiology and response to ischemia, risks associated with procedures involving the aortic arch remain considerable. Disruption of blood flow to the brain is mandatory, and the development of methods to protect the brain during this period has progressed rapidly. The use of deep hypothermic circulatory arrest (DHCA), topical hypothermia, cerebral perfusion, and pharmacologic manipulation of cerebral metabolic function have all become commonplace during aortic arch surgery. Despite the success these methods have had in protecting the brain, even for ischemic periods of as long as 1 hour, neurologic sequelae remain commonplace. Evidence that the period of cerebral ischemia might not be the prime factor in development of neurologic injury is developing. Methods to prevent cerebral dysfunction during the “recovery phase” of circulatory arrest are also in development. Of prime importance, however, is the surgical management of the repair, which encompasses all phases of intraoperative and postoperative management of these patients.
The development of aortic arch DHCA techniques dates to the early work of Griepp et al,20 who first described the method in a series of four patients. Although initially cumbersome, the techniques of DHCA rapidly became simpler and more easily applied. This technique quickly became the standard for procedures involving the aortic arch.
The same techniques also became adapted to repairs on the distal ascending aorta, allowing for short, safe periods of circulatory arrest to excise the distal clamp site, completely view the aortic anatomy, and perform the distal anastomosis without leaving any clamp-compromised tissue. Clampless distal anastomoses are now the standard for all ascending aortic repairs in the authors' institution and have become standard for repairs on the distal arch, approached from the left chest.
Foremost of concern during the repair of the aortic arch is the interval of circulatory arrest. Initially, periods of as long as 1 hour of ischemia were common when complete arch repairs were performed. As correlations between intervals of arrest and incidence of cerebral dysfunction became known, methods to decrease the effect of the hypoxic interval were sought. Among the various techniques used were pharmacologic manipulations of cerebral metabolism,18 alterations of superoxide radical18 and excitatory amino acid4, 21, 51, 52, 53, 60 concentrations, and reduction of cerebral edema.68 Despite initial encouraging reports, most of these manipulations have failed to reliably alter the observed incidence of neurologic dysfunction following DHCA. Consequently, the use of temperature manipulation and limiting cerebral ischemia remains the mainstay of cerebral protection during procedures involving the aortic arch.19
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| Address reprint requests to Randall B. Griepp, MD, Department of Cardiothoracic Surgery, The Mount Sinai Medical Center, One Gustave L. Levy Place, Box 1028, New York, NY 10029 |
Vol 17 - N° 4
P. 767-778 - novembre 1999 Retour au numéro
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- SURGICAL TECHNIQUES : Thoracoabdominal Aorta
- Joseph S. Coselli, Scott A. LeMaire
- THE USE OF BIOLOGICAL GLUE IN AORTIC SURGERY
- Jean Bachet, Daniel Guilmet
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