Efeitos das cardioplegias sangüínea e cristalóide no miocárdio hipertrófico de coelho: avaliação estrutural e ultra-estrutural

Abstract

Efeitos das cardioplegias sangüínea e cristalóide no miocárdio hipertrófico de coelho: avaliação estrutural e ultra-estruturalEffects of myocardial protection on hypertrophic rabbit hearts: structural and ultra structural analysis Abstract Objective: To experimentally compare the structural and ultrastructural changes in isolated hypertrophied rabbits' hearts submitted to cardiac arrest protected using blood and crystalloid cardioplegia solutions.Method: The study comprised two experimental groups and one control group. In Experimental Group I, cardiac arrest was achieved by the continuous infusion of a tepid blood cardioplegia solution. In Experimental Group II, cardiac arrest was obtained by an intermittent infusion of a cold crystalloid cardioplegia solution. In the Control Group the hearts were submitted to normothermic anoxic arrest for 45 minutes. After the procedures, eight samples of the left ventricle lateral wall were collected and fixed in 10% formaldehyde and 2.5% glutaraldehyde for structural and ultrastructural analysis. Results:The structural and ultrastructural results demonstrated that the hearts submitted to cardiac arrest protected by continuous tepid blood cardioplegia, Group I, were better preserved and with less accentuated cellular alterations compared to those submitted to cardiac arrest protected using intermittent cold crystalloid cardioplegia and the Control Group.Conclusion: Continuous tepid blood cardioplegia was more efficient in the preservation of the structural and ultrastructural integrity of the myocardium when compared to intermittent cold crystalloid cardioplegia.Descriptors: Cardioplegic solutions, pharmacology. Hypertrophy. Cardiac surgical procedures. 25CRESSONI, ES ET AL -Effects of myocardial protection on hypertrophic rabbit hearts: structural and ultra structural analysis Braz J Cardiovasc Surg 2007; 22(1): 24-32 membrane polarized cardioplegia with tetrodotoxin, esmolol and other formulas [15].Thus, the current work aims at evaluating structural and ultrastructural alterations occurring after the use of blood and crystalloid cardioplegic solutions in hypertrophic myocardium of rabbits. METHODNine Norfolk-2000 rabbits variant Botucatu of both genders were utilized with weights ranging from 1850 to 2350 kg, all supplied by the animal house on the Campus of Botucatu -UNESP. The research was approved by the Research Ethics Committee of the Medical School in Botucatu -UNESP. Conditioning of myocardial hypertrophyAfter general anesthesia of the animal using sodium pentobarbital, a crosswise incision was performed in the cervical region, slightly above the sternum. The aortic artery was identified, pericardiotomy was performed and the ascending aorta was isolated and coarctation was provoked using the technique described by Martins et al. [16]. After 5 months with hypertrophic hearts (Figure 1), the animals were euthanized. INTRODUCTIONHypertension is the greatest cause of left ventricle hypertrophy [1], affecting around one third of the hypertensive population [2], leadi...

Proteção miocárdica ao coração hipertrofiado: o eterno desafio

“…Cressoni et al [50] showed, experimentally as well, the superiority of cardiac protection by tepid, continuous cardioplegic solution in the preservation of myocardial ultrastructural and structural integrity when compared to intermittent cold crystalloid cardioplegic solution. Martins et al [51] in a similar experiment proved the efficacy of myocardial protection fostered by retrograde, antegrade, and continuous blood cardioplegia, which allowed to further improve the outcomes, mainly those related to cardiac rhythm.…”

Análise ultra-estrutural do miocárdio usando solução cardioplégica cristalóide com e sem procaína em pacientes submetidos à troca valvar aórtica

“…Several authors have shown that the electron microscopy is a mean of direct assessment, becoming a highly-sensitive method to detect early cell damage in the myocytes [22][23][24][25][26].…”

Effect of Shenfu Injection on Isolated Empty Beating Hearts from Miniature Pigs

“…In order to optimize the effect of heart preservation, new approaches have been explored. For instance, continuous perfusion of harvested hearts can safely prolong the preservation period compared with cold static storage [ 1 - 3 ] . In cold static storage, ischemia-reperfusion injury is inevitable, and continuous perfusion of harvested hearts can provide a near-physiologic environment for the heart by continuously infusing it with a warm, oxygen-rich medium.…”