Similar long-term cardiovascular effects of propofol or isoflurane anesthesia during ischemia/ reperfusion in dogs.
OBJECTIVE
To compare the long-term functional and metabolic effects of propofol or isoflurane general anesthesia in a canine model of ischemia/reperfusion.


METHODS
Using magnetic resonance (MR) techniques, we monitored both regional metabolism ((31)P MR spectroscopy) and systolic function of the heart ((1)H MR imaging) throughout a two-hour occlusion of the left anterior descending coronary artery and ten days of reperfusion. Twenty-two beagles were randomized into isoflurane and propofol general anesthesia groups (n = 10, n = 12 respectively). Contrast-enhanced MR imaging was used to measure infarct size (% of left ventricle that was necrotic) and coronary blood flow was determined using radioactively labelled microspheres.


RESULTS
Cardiac metabolism, as monitored by intracellular pH and high-energy phosphate ratios, was not significantly different between the two groups throughout the protocol. Relative to propofol, isoflurane reduced the depression of left ventricular ejection fraction (EF) during the ischemic period [isoflurane 68.5% +/- 4.2%, propofol 58.3% +/- 2.0% of baseline (B); P = 0.04], propofol increased the recovery of EF at day three (isoflurane 63.9% +/- 4.3%, propofol 74.0% +/- 2.5% of B; P = 0.05). By day ten, EF in both groups was similar. Infarct sizes were also similar at day ten (isoflurane 15.7% +/- 3.0%, propofol 13.2% +/- 2.2%). Normalizing these by the region at risk (volume of tissue with low blood flow during the occlusion) to assess infarct ratios was also not significant (isoflurane 0.58% +/- 0.08%, propofol 0.54% +/- 0.07%).


CONCLUSIONS
There were no significant differences between the two anesthetic groups at day ten, suggesting that any apparent dissimilarities in early cardiovascular effects were short-term only. These results indicate that isoflurane and propofol produce equivalent long-term cardiovascular effects following ischemia/reperfusion.
Thompson
Kerry
K
Imaging Division, Lawson Health Research Institute. the Division of Cardiology, Faculty of Medicine and Dentistry, University of Western Ontario. St. Joseph's Health Care, London, Canada. kthompso@lri.sjhc.london.on.ca
Wisenberg
Gerald
G
Sykes
Jane
J
Thompson
R Terry
RT
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects; D004285:Dogs; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D007530:Isoflurane / Q000494:pharmacology*; D008279:Magnetic Resonance Imaging; D019028:Magnetic Resonance Imaging, Cine; D009682:Magnetic Resonance Spectroscopy; D009203:Myocardial Infarction / Q000209:etiology / Q000473:pathology; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology*; D009206:Myocardium / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D013908:Thoracotomy
D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D010710:Phosphates; D007530:Isoflurane