Objective To investigate the protective effects of metallothionein （MT） for immature myocardium and myocardial interstitium.Methods Twenty-four rabbits （aged 14-21 days） were divided into 4 groups with random number table, 6 each group. Distilled water was injected intraperitoneally in control group and 3.6% ZnSO4 （1.5 ml/kg） was injected intraperitoneally in group 1, group 2 and group 3. Control group, group 1, group 2 and group 3 isolated working rabbit heart model were used in 24h, 12h, 24h and 48h after intraperitoneally respectively. The MT content, recovery of hemodynamics, biochemistry and myocardial ultrastructure were tested. Results The MT content, hemodynamics recovery, adenosine triphosphate （ATP） content, superoxide dismutase activity, Ca2＋-ATPase activity, synthesizing ATP activity of mitochondria, hydroxyproline in group 2 and group 3 were higher than those in control group and group 1 （P 〈 0. 01）. The myocardial watery content, creatine kinase and dehydrogenase leakage, malondialdehyde content, endothelin, mitochondrial Ca2＋ content in group 2 and group 3 were lower than those in control group and group 1（P〈0.01）. The myocardial ultrastructure injuries were less in group 2 and group 3 than that in control group and group l. Conclusion This study demonstrates that myocardial MT prolonged expression can be induced by ZnSO4 and the ischemia-reperfusion injury of immature myocardium and myocardial interstitium could be reduced by MT.
Objective To summarize the experiences of donor heart procurement of heart transplantation so as to improve the efficiency of donor heart protection. [WTHZ]Methods [WTBZ]From April 2002 to October 2006, sixtyone patients with endstage heart disease had undergone orthotopic heart transplantation. Donors were all male brain deaths, aged from 21 to 53, and 5 of them were older than 40. There were 6 cases in which the weight difference between donor and recipient＞20%, and the rest ≤±20%. Fortyfive cases had the same ABO blood type, and 16 had matching ABO blood type. Four donor hearts were procured under the condition of stable hemodynamics and enough oxygen after brain death(typeⅠ), fortyfour donor hearts were procured under the condition of brain death with acute hemorrhage and hypovolemia (typeⅡ), and 13 donor hearts were procured under the condition of brain death with cardiac arrest (typeⅢ). Twenty cases underwent standard transplantation procedure, one underwent total heart transplantation procedure and 40 underwent bicaval transplantation procedure. The donor heart cold ischemic period ranged from 52 to 347 min（92±31 min）, and 13 cases were more than 240 min. Results Two cases died of low cardiac output syndrome on 7th and 9th day after operation respectively, and their donor heart cold ischemic period were 327 and 293 min respectively. The rest of patients all recovered and discharged. One died of acute rejection on 18th month after operation because of rejecting immunosuppressive agents, and 1 died in traffic accident on 23rd month after transplantation. The rest 57 cases survived 6-59 months(mean 35 months), and had good life quality with NYHA cardiac function classification in 0-I grade. Conclusions Heart transplantation with donor aged over 40 may also have satisfactory results. Patients with endstage dilated cardiomyopathy can procure donor heartsfrom donors with heavy weight. Using different techniques to procure donor hearts may furthest reduce myocardial injury. Donor hearts which have been protected by myocardium protecting liquid for a long time should be used with caution.
Abstract： Objective To assess the effects of simultaneous antegrade/retrograde cardioplegia (SARC) on myocardial perfusion and energy metabolism in ischemic myocardium using magnetic resonance imaging (MRI). Methods After the hearts were harvested from 18 domestic pigs, left anterior descending artery, aorta, anterior ascending cardiac vein and coronary sinus were cannulated to establish the perfusion routes. 6 hearts were used to assess the effects of SARC on myocardial perfusion. Energy metabolism was observed in the other 12 pig hearts. MRI was used to monitor the distribution of contrast agent (gadoliniumdiethylenetriamine penlaacetic acid, Gd-DTPA) in the myocardium after its injection through arterial and retrograde perfusion routes. The efficacies in sustaining myocardial perfusion and energy metabolism were evaluated by using phosphorus-31 magnetic resonance spectroscopy (31P MRS) during antegrade cardioplegia (AC) and SARC respectively. Results It was found that injection of Gd-DTPA into the aorta during AC did not result in signal increase in the ischemic myocardium on MRI. During SARC, however, Gd-DTPA was found in the ischemic region as well as in the other regions, no matter if it was given into the aorta or into the coronary sinus. Moreover,31P spectra showed that occlusion of LAD during AC resulted in severe decrease of the levels of phosphocreatine (PCr) and adenosine triphosphate (ATP), while the level of inorganic phosphate (Pi) increased in LAD-support myocardium. The abnormal metabolic changes were completely abolished by use of SARC. Conclusion It is concluded that SARC can deliver cardioplegic solution to the myocardium distal to a coronary occlusion and can sustain normal energy metabolism in the jeopardized myocardium.
Objective To investigate the role of mitochondrial adenosine triphosphatesensitive potassium channel(mitoKATP) in immature myocardial ischemic preconditioning, and to provide evidence for immature myocardial protection. Methods Langendorff isolated heart infused model was used in the experiment. Twentyfour rabbits (aged from 14 to 21 days) were randomly divided into 4 groups：ischemiareperfusion group（I/R group）, myocardial ischemic preconditioning group(E1 group), 5hydroxydecanoate(5-HD) group (E2 group) and Diazoxide (Diaz) group(E3 group). Hemodynamics recovery rate, myocardial water content(MWC), the leakage rates of serum creatine kinase and lactate dehydrogenase, adenosine triphosphate content, superoxide dismutase activity, malondialdehyde content, myocardial cell Ca2+ content and myocardial mitochondrial Ca2+ content, myocardial mitochondrial Ca2+-ATPase activity, the adenosine triphosphate(ATP) synthesizing ability of myocardial mitochondria were tested, and myocardial ultrastructure was observed via electron microscopy. Results The hemodynamics recovery rate, myocardial water content(P＜0.05), adenosine triphosphate content, superoxide dismutase activity, myocardial mitochondrial Ca2+-adenosine triphosphyatase(ATPase) activity and the ATP synthesizing ability of myocardial mitochondria of the rabbits in E1 and E3 group were significantly better than that in I/R group and E2 group(P＜0.05). Malondialdehyde content, the leakage rates of serum creatine kinase and lactate dehydrogenase, myocardial cell Ca2+ content and myocardial mitochondrial Ca2+ content of the rabbits in E1 group and E3 group were significantly lower than that in I/R group and E2 group (P＜0.05). The myocardial ultrastructure injury in E1 and E3 group were significantly reduced compared with that in I/R and E2 group. Conclusion Myocardial ischemic preconditioning has significant protective effects on immature myocardium. Its mechanism may be related to the activation of mitoKATP.
Objective To systematically review the influence of tight heart rate (HR) control on the efficacy of perioperative β-blockade, and discuss the effective measures of perioperative myocardial protection. Methods We searched the PubMed, OVID, EMbase, the Cochrane Library and Chinese Biomedical Database (CBM) for randomized controlled trials on evaluating perioperative β-blockers after noncardiac surgery. The quality of the included studies was evaluated by the method recommended by the Cochrane Collaboration. Meta-analyses was conducted by using the Cochrane Collaboration’s RevMan software. Results Thirteen RCTs including 11 590 patients were included. The combined results of all studies showed cardioprotective effect of β-blockers (OR=0.64, 95%CI 0.50 to 0.80, P=0.000 1), with considerable heterogeneity among the studies (I2=57%). However, grouping the trials on the basis of maximal HR showed that trials where the estimated maximal HR was 100 bpm were associated with cardioprotection (OR=0.37, 95%CI 0.26 to 0.52, Plt;0.000 01) whereas trials where the estimated maximal HR was 100 bpm did not demonstrate cardioprotection (OR=1.13, 95%CI 0.81 to 1.59, P=0.48) with no heterogeneity (I2=0%). Conclusion The evidence suggests that effective control of HR is important for achieving cardioprotection and that administration of β-blockers does not reliably decrease HRs in all patients. Judicious use of combination therapy with other drugs may be necessary to achieve effective postoperative control of HR.
Objective\ In order to assess and evaluate the clinical results of cold blood cardioplegia and intermittent cross clamping as myocardial preservation in coronary artery bypass grafting(CABG).\ Methods\ According to the management methods, 2 013 cases for elective, isolated CABG were divided into two groups at St.George’s Hospital, London.Cold blood cardioplegia group: 596 patients treated with cold blood cardioplegia, and hypothermic ventricular fibrillation group: 1 417 patients treated with intermitt...
Objective To analyze the effect of myocardial protection between modified Del Nido cardioplegia and St. Thomas Hospital Cardioplegia in adult patients with aortic valve and mitral valve replacement. Methods From January 2014 to June 2016, 140 patients underwent aortic valve and mitral valve replacement in our hospital. According to different cardioplegia, the patients were divided into two groups including a modified Del Nido cardioplegia group (70 patients, 37 males, 33 females at mean age of 53.13±9.52 years) and a St. Thomas cardioplegia group (70 patients, 32 males, 38 females, at age of 50.71±9.29 years). We collected clinical data of the patients before operation (T1), 2 h after aortic unclamping (T2), 24 h after operation (T3) and 48 h after operation (T4). Indexes of muscle enzymes including blood center creatine kinase (CK), creatine kinase isoenzyme (CK-MB) concentration and liver function indexes including urea nitrogen (BUN), creatinine (Cr), alanine aminotransferase (ALT), aspartate aminotransferase (AST) concentrations, and compared the postoperative and follow-up clinical data. Results There was no statistical difference in age, weight, gender, ejection fraction baseline data between the two groups (P>0.05). All patients were successfully completed combined valve replacement under cardiopulmonary bypass. The cardiopulmonary time was no statistical difference between the two groups (P>0.05). However, compared with St. Thomas cardioplegia group, modified Del Nido group was less in perfusion (1.19±0.39vs. 2.99±0.75, P<0.001), shorter in aortic clamping time (P=0.003). No statistical difference was found in defibrillation rate after resuscitation between the two groups (P=0.779). Biochemical indicators were not statistically different at different time points between the two groups (P>0.05). Conclusion Modified Del Nido cardioplegia has the same effect on myocardial protection with St. Thomas cardioplegia in adult patients. It reduces the frequency of reperfusion, and shortens the clamping time. There is no additional injury in the important organs such as liver, kidney. Modified Del Nido cardioplegia myocardial protection ability in adult heart valve surgery is feasible.