J Thorac Cardiovasc Surg 2003;125:441
© 2003 The American Association for Thoracic Surgery
Reply
Robert Bonser, FRCP, FRCS,
Deborah Harrington, MRCS,
Domenico Pagano, MD, FRCS
Department of Cardiothoracic Surgery, Queen Elizabeth Hospital, Edgbaston, Birmingham B15 2TH, United Kingdom
Reply to the Editor:
We thank Elami for his comments concerning our work on retrograde cerebral perfusion (RCP).
1 We acknowledged in our discussion that RCP could contribute to metabolic support during hypothermic circulatory arrest and that this contribution could be increased by the use of vasodilators. It is also possible that the use of anesthetics or neuroprotective agents during RCP might afford neuroprotection. The series quoted by Elami, however, describes only anecdotal evidence from 3 patients undergoing differing pharmacologic interventions. 2 This report described no monitoring of cerebral metabolism or perfusion, therefore making inferences regarding cerebral metabolic activity and blood flow unreliable. We have previously reported that RCP can provide some brain perfusion, but we have questioned what fraction of retrograde flow provides true brain perfusion. 3,4 It is quite possible that increased flow achieved by means of vasodilator administration bypasses the brain through venovenous and venoarterial collaterals. 4 Any assumption that increasing flow increases true brain perfusion and neuroprotection requires rigorous enquiry. We would agree that the jury remains out on RCP and that a beneficial clinical effect remains to be proven. Such therapeutic interventions therefore require assessment as part of randomized controlled trials if their efficacy is to be completely investigated.
References
- Bonser RS, Wong CH, Harrington D, Pagano D, Wilkes M, Clutton-Brock T, et al. Failure of retrograde cerebral perfusion to attenuate metabolic changes associated with hypothermic circulatory arrest. J Thorac Cardiovasc Surg. 2002;123:943-50.[Abstract/Free Full Text]
- Shenkman Z, Elami A, Weiss YG, Glantz L, Milgalter E, Drenger B, et al. Cerebral protection using retrograde cerebral perfusion during profound hypothermic circulatory arrest. Can J Anaesth. 1997;44:1096-101.[Medline]
- Pagano D, Boivin CM, Faroqui MH, Bonser RS. Retrograde perfusion through the superior vena cava perfuses the brain in human beings. J Thorac Cardiovasc Surg. 1996;111:270-2.[Free Full Text]
- Wong C, Bonser RS. Retrograde perfusion and true reverse brain blood flow in humans. Eur J Cardiothorac Surg. 2000;17:597-601.[Abstract/Free Full Text]
