Pre-occlusion ischaemia, not sevoflurane, successfully preconditions the myocardium against further damage in porcine in vivo hearts.
BACKGROUND
Sevoflurane is proposed to possess important tissue protective effects based on experimental ischaemia-reperfusion studies from models with collateral coronary flow, unlike that of the normal human or the porcine heart. The objective was to evaluate the infarct-reducing capability of pre-ischaemic sevoflurane inhalation on myocardial infarct size in a porcine model.


METHODS
The study comprised 33 pigs under pentobarbital anaesthesia. Animals were divided into three groups: control (CON), sevoflurane intervention (SEVO) and ischaemic preconditioning (IP). The distal left anterior descending coronary artery was occluded for 40 min with a percutaneous coronary intervention catheter. Before occlusion, group IP underwent two 5-min ischaemia cycles, whereas SEVO received two 5-min sevoflurane 4%v/v inhalation cycles. Animals were reperfused for 150 min. We then measured risk area (AAR) and infarct size (IS) after tetrazolium staining. The [IS/AAR-ratio] was calculated. Haemodynamics and transthoracic tissue-Doppler echocardiography were monitored.


RESULTS
Control animals developed a myocardial infarction in 46.4 (+/- 6.2)% (mean +/- SEM) of the AAR. Both SEVO and IP groups had infarction mitigated, to 34.4 (5.7)% and 23.1 (5.3)%, respectively; however, only in the IP group was this significant. No significant differences between groups with respect to AAR, haemodynamics or echocardiographic variables were found.


CONCLUSIONS
Pre-ischaemic sevoflurane was found to reduce the extent of myocardial necrosis, but the change was not significant, whereas IP reduced IS by 50% (P= 0.038). Cardioprotection is species related and no previous results from porcine models have found sevoflurane to reduce IS. Anaesthetic washout, insufficient exposure or collateral coronary blood supply, dissimilar to human, may account for positive results in rodent models.
Larsen
J R
JR
Department of Anaesthesiology and Intensive Care, Aarhus University Hospital, Aarhus, Denmark. jens.rolighed@ki.au.dk
Aagaard
S R
SR
Hasenkam
J M
JM
Sloth
E
E
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002316:Cardiotonic Agents / Q000008:administration & dosage; D003326:Coronary Circulation / Q000187:drug effects; D004195:Disease Models, Animal; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D019194:Ischemic Preconditioning / Q000379:methods*; D008738:Methyl Ethers / Q000494:pharmacology*; D009203:Myocardial Infarction / Q000517:prevention & control*; D009336:Necrosis / Q000517:prevention & control; D012720:Severity of Illness Index; D000077149:Sevoflurane; D013552:Swine; D013997:Time Factors; D016896:Treatment Outcome
D018685:Anesthetics, Inhalation; D002316:Cardiotonic Agents; D008738:Methyl Ethers; D000077149:Sevoflurane