ORIGINAL ARTICLES  CARDIAC SECTION 

The Journal of Cardiovascular Surgery 2012 February;53(1):107-12

Copyright © 2012 EDIZIONI MINERVA MEDICA

language: English

Influence of temperature management on neurocognitive function in biological aortic valve replacement. A prospective randomized trial

Fakin R. ¹, Zimpfer D. ², Sodeck G. H. ³, Rajek A. ⁴, Mora B. ⁴, Dumfarth J. ², Grimm M. ², Czerny M. ⁵ ✉

¹ Division of General Thoracic Surgery, University Hospital Bern, University of Bern, Bern, Switzerland; ² Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria; ³ Department of Emergency Medicine, Medical University of Vienna, Vienna, Austria; ⁴ Department of Cardiothoracic and Vascular Anesthesiology, Medical University of Vienna, Vienna, Austria; ⁵ Division of Cardiovascular Surgery, Swiss Cardiovascular Center, University Hospital Bern, University of Bern, Bern, Switzerland

AIM: Aim of this study was to elucidate if postoperative neurocognitive function after biological aortic valve replacement (AVR) can be influenced by temperature management during cardiopulmonary bypass (CPB).
METHODS: In this prospective randomized study, we measured the effect of mild hypothermic (32 °C, N.=30) vs. normothermic (37 °C, N.=30) CPB on neurocognitive function. All patients underwent elective isolated biological AVR (mean age 67±8 years, mean additional EuroSCORE 5.6±2.4). Neurocognitive function was objectively measured by means of objective P300 auditory-evoked potentials before surgery, one week and four months after surgery. Clinical data and outcome were monitored.
RESULTS: P300 evoked potentials were comparable between patients operated with mild hypothermic (370±30 ms) and normothermic CPB (373±32 ms) before surgery (P=0.85). P300 peak latencies were prolonged (=impaired) in patients operated with normothermic (402±29, P<0.0001) as well as with mild hypothermic CPB (405±30 ms, P<0.0001) one week after surgery. Even four months after surgery, still impairment of P300 peak latencies could be documented in either patients operated with normothermic (394±28 ms) and mild hypothermic CPB (400±33 ms,) in repeated measures analysis of variance (P=0.042). Group comparison revealed no difference between patients operated with normothermic and mild hypothermic CPB at one week (P=0.54) and four months (P=0.67) after surgery. Clinical data as well as postoperative adverse events were comparable between the two groups.
CONCLUSION: Normothermic temperature management during CPB is non-inferior to hypothermic in means of neuroprotection. Since patients after biological aortic valve replacement show a subclinical but measurable cognitive deficit up to four months after surgery, other factors have to be addressed to add further benefit to the extremely good results of open biological AVR.