Cardioprotective effects of acute isovolemic hemodilution in a rat model of transient coronary occlusion.
OBJECTIVE
Following isovolemic hemodilution (AIH), lowering blood viscosity induces acceleration of erythrocyte velocity resulting in improved tissue oxygen delivery. Using a rat model of myocardial infarct, we tested the hypothesis that AIH would attenuate myocardial damage due to transient coronary occlusion.


METHODS
Prospective, randomized, and controlled animal study.


METHODS
Animal research laboratory in a university hospital.


METHODS
Male Sprague-Dawley rats.


METHODS
All rats were subjected to 30 mins of left coronary artery occlusion followed by 48 hrs of reperfusion. Before the ischemic period, the anesthetized rats were randomly allocated to undergo either 15 mins of waiting (controls) or AIH to achieve a hematocrit of 30% (AIH-CO) by stepwise blood withdrawal and isovolemic compensation with 6% hydroxyethylstarch 200-0.5.


RESULTS
Hemodynamic variables were comparable in the two groups, except for higher indexes of stroke volume in the AIH-CO group. During coronary occlusion and the reperfusion period, AIH resulted in a lower incidence of fatal ventricular tachyarrhythmia (17% vs. 50% in control group, p < .05) and higher survival at 48 hrs of postreperfusion (83% vs. 42%, p < .05).Preischemic hemodilution significantly attenuated myocardial damage as shown by lower release of cardiac troponin I and reduction in myocardial infarct size as measured by tetrazolin staining. Histologic examination revealed no difference regarding peri-ischemic infiltration with neutrophil granulocytes.


CONCLUSIONS
Our data provide the first experimental demonstration that preischemic moderate AIH confers cardioprotection and improves survival in a rat model of myocardial infarct.
Licker
Marc
M
Department of Anesthesiology, Pharmacology and Surgical Intensive Care, University Hospital of Geneva, Geneva, Switzerland.
Mariethoz
Ewa
E
Costa
Manuel Jorge
MJ
Morel
Denis
D
D000818:Animals; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000502:physiology; D001810:Blood Volume; D003327:Coronary Disease / Q000097:blood / Q000503:physiopathology / Q000517:prevention & control*; D004195:Disease Models, Animal; D006339:Heart Rate / Q000502:physiology; D006400:Hematocrit; D006438:Hemodilution / Q000379:methods*; D006454:Hemoglobins / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D019210:Troponin I / Q000097:blood
D006454:Hemoglobins; D019210:Troponin I