Use of (all-blood) miniplegia versus crystalloid cardioplegia in an experimental model of acute myocardial ischemia.
OBJECTIVE
Several methods of myocardial protection have been used. The use of all-blood solutions modified with glutamate and aspartate has increased. Its use in situations of acute ischemia provides improved contractile function, "resuscitating" the previously lesioned muscle. The dilution preconized by literature is around 25% of the hematocrit. The present study evaluates an all-blood cardioplegia solution with tepid 1% dilution, denominated miniplegia.


METHODS
Pigs of the Large-White breed were used with an isolated heart and perfused with blood of a support animal. Three groups (n = 7 per group) were designated with the following treatments: Control group (CO), St. Thomas solution (ST), continuous normothermic all-blood solutions (SG). After the stabilization period, systolic pressure (PS), diastolic pressure (PD), developed pressure (PD), stress of the wall, elastance, and passive stiffness were recorded. The hearts were submitted to 30 minutes of regional ischemia with the clamping of the anterior interventricular artery, and subsequently to 90 minutes of global ischemia with the use of the three different treatments during this period. At the beginning of global ischemia, the coronary clamp was removed. The hearts were again reperfused. Upon three minutes into reperfusion the hearts were defibrillated when necessary. Measurements were taken every 30 minutes to 90 minutes into reperfusion.


RESULTS
The SG presented a better recovery of the ventricular function in several of the parameters recorded. The ST group was inferior to the SG group, which in turn was superior to the CO group in some of the parameters analyzed. A higher number of defibrillations were needed to reestablish coordinated heart beats in the ST and CO groups. There were no differences related to the percentage of wet weight between the SG and ST groups, and the percentage was higher in the CO group.


CONCLUSIONS
The use of all-blood miniplegia provided superior protection when compared to global ischemia or crystalloid cardioplegia in acutely ischemic hearts. The model employed is very close to the clinical situation due to the use of blood as a perfusate.
Petrucci
Orlando
O
Discipline of Cardiac Surgery, Department of Surgery, School of Medical Sciences at Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brasil. orlandopetrucci@gmail.com
Wilson Vieira
Reinaldo
R
Roberto do Carmo
Márcio
M
Martins de Oliveira
Pedro Paulo
PP
Antunes
Nilson
N
Marcolino Braile
Domingo
D
D000208:Acute Disease; D000818:Animals; D001639:Bicarbonates / Q000008:administration & dosage; D001769:Blood; D002122:Calcium Chloride / Q000008:administration & dosage; D006324:Heart Arrest, Induced / Q000379:methods*; D006439:Hemodynamics; D008274:Magnesium / Q000008:administration & dosage; D017202:Myocardial Ischemia / Q000503:physiopathology*; D015425:Myocardial Reperfusion; D011189:Potassium Chloride / Q000008:administration & dosage; D017680:Potassium Compounds / Q000008:administration & dosage*; D012965:Sodium Chloride / Q000008:administration & dosage; D034421:Sus scrofa
D001639:Bicarbonates; D017680:Potassium Compounds; C041711:St. Thomas' Hospital cardioplegic solution; C018369:potassium cardioplegic solution; D012965:Sodium Chloride; D011189:Potassium Chloride; D008274:Magnesium; D002122:Calcium Chloride