Objective To observe the protective effects of diazoxide-preconditioning on myocardial ischemiareperfusion injury of rats and discuss its possible mechanisms. Methods Fourteen healthy SD rats were randomly divided into two groups（7 each group）,In diazoxide-preconditioning group diazoxide was injected with the dosage of 12.5mg/kg through the vein,and in control group the media with the same amount was only given before ischemia. The left anterior descending branch was ligated for 2 hours. The heart was quickly excised after 2 hours reperfusion to be used for measurement of the quantity of malondialdehyde（MDA）, the activity of superoxide dismutase （SOD）, the size of myocardial infarct area, and the cell apoptosis and ultrastructure in ischemic area. Results Compared with the control group, the quantity of MDA,the percentage of the weight of myocardial infarct area/ischemic area, and the rate of cell apoptosis in the diazoxide-preconditioning group were greatly reduced （P〈0.05, 0. 01）. The damage of cell uhrastructure was obviously alleviated,Conclusion Diazoxide-preconditioning provides evident cardioprotective effect on the myocardial ischemia-reperfusion injury of rats.
Erythropoietin （EPO） is known as a classical hematopoietic growth factor, which has been used to treat anemia caused by different reasons. In recent years, EPO＇s non-hematopoietic biological effects have gradually become a focus. Among these effects, EPO＇s tissue protection is most attractive and EPO has been proved to protect many different tissues and organs. Myocardial protection has always been the important and key topic in the field of cardiovascular diseases. Reports about EPO＇s myocardial protective effects have been published in the recent two years, which direct the research about myocardial protection with new ideas. In this article, the discoveries and unsolved problems associated with EPO＇s myocardial protection were reviewed.
ObjectiveTo compare the myocardial protective effect of HTK solution and St.ThomasⅡ(STH) solution in immature rabbit myocardium at different cardiac arrest time. MethodsAccording to cardioplegia and cardiac arrest time, 32 immature New Zealand white rabbits (aged 2-3 weeks) were randomly divided into four groups. A group SO (8 rabbits) underwent 1 hour cardiac arrest with STH solution, a group ST (8 rabbits) underwent 2 hours cardiac arrest with STH solution, a group HO (8 rabbits) underwent 1 hour cardiac arrest with HTK solution, a group Ht (8 rabbits) underwent 2 hours cardiac arrest with HTK solution. Compare the myocardial protective effect of HTK and STH solution in immature myocardium at different cardiac arrest time. ResultsThe Langendorff models were successfully established in 30 cases (8 cases in the group SO and HO, 7 cases in the group ST and HT). There were no statistical differences in hemodynamics and myocardial enzyme (CK-MB, LDH) (P > 0.05), but HTK solution reduced the activity of nitric oxide synthase (NOS) and content of malonaldehyde (MDA) and NO, maintained high activity of superoxide dismutase (SOD) and Ca2+-ATPase (P < 0.05), performed more effective myocardial protection for immature myocardium. ConclusionHTK solution has more effective myocardial protection for immature myocardium than STH solution does, but STH solution still has good outcomes within short cardiac arrest time (1h).
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.
Cardiac injury is a major complication of cardiac surgery. Surgical manipulation, systemic inflammatory response and cardiac ischemia/reperfusion injury (IRI)are main reasons of cardiac injury. Gentle and swift surgical manipulation can reduce mechanical myocardial injury, shorten myocardial ischemic time, and reduce myocardial IRI. Satisfactory myocardial protection plays a key role to improve postoperative recovery. In recent years, more and more myocardial protection strategies are employed to reduce myocardial IRI and improve myocardial protection, including modifications of temperature, composition and instillation approach of cardioplegia in order to increase myocardial oxygen supply, decrease myocardial oxygen consumption, inhibit inflammatory response and eliminate oxygen free radicals. Endogenous myocardial protection is also achieved by supplement of certain medications in cardioplegia.
Objective To investigate the value of systemic-normothermic/cardiac-hypothermic cardiopulmonary bypass（CPB）on operation of congenital heart disease. Methods Thirty patients of congenital heart disease were randomly divided into two groups, the normothermia group（n=15）and hypothermia group（n=15）. The changes of CPB time, aortic cross-clamp time,operation time and postoperative drainage and the value of blood cell were observed. Results The duration of CPB （37. 5 ±11. 6rain vs. 51. 6± 12. 0 min, P〈0. 05） and operation time （2.2± 0.6h vs. 2. 7±0. 5h, P〈0. 01） in normothermia group were shorter than those of hypothermia group statistically, the differences of postoperative drainage and the value of blood cells between two groups were not statistically significant. Conclusion The use of systemic-normothermic/cardiac-hypothermic CPB on operation of congenital heart disease shows that the time of operation is shorter remarkly , and it could be clinically used safely.
Hemoglobin-based oxygen carriers (HBOCs) is a kind of blood substitutes. It is a separated, ultra-purified, modified human or bovine hemoglobin in a balanced saline solution. After modification, it has longer half-time, less renal toxicity, and better delivery of O2 even at low temperature and pH. Its shelf life is long and it dose not require cross-matching. In the field of cardiac surgery, the use of HBOCs can reduce the amount of transfusion postoperatively, and can be used in cardiopulmonary bypass priming and myocardial protection.
Abstract: Objective To evaluate myocardial protection effect of different myocardial protective strategies for patients undergoing double valve replacement （DVR）?. Methods From Jun. 2005 to Dec. 2005, 32 patients with predominant aortic valve stenosis undergoing DVR in Xinqiao Hospital were included in this study. These patients were randomly divided into four groups with 8 patients in each group： （1） antegrade perfusion group：Cold-blood cardioplegia was delivered antegradely through aortic root, and mitral valve replacement （MVR）was performed. Then cold-blood cardioplegia was delivered antegradely through left and right coronary ostia, and aortic valve replacement （AVR） was performed； （2）retrograde perfusion group：Cold-blood cardioplegia was delivered retrogradely and intermittently through coronary sinus, and DVR was performed； （3）antegrade＋retrograde perfusion group：The route of cold-blood cardioplegic infusion was antegrade during MVR procedure first and then retrograde during AVR procedure；and （4）beating heart group：Oxygenated blood from cardiopulmonary bypass machine was delivered retrogradely and continuously through coronary sinus, and DVR was performed with beating heart. Early clinical outcomes were observed. Serum cardiac troponin I （cTnI） was measured by enzyme-linked immunosorbent assay（ELISA）. Serum creatine kinase-MB （CK-MB） and myocardial lactic acid release rate were measured by Hitachi7150 Automatic Chemistry Analyzer. Myocardial mitochondria malondialdehyde （MDA） level was measured through thiobarbituric acid reagent species analysis. Results All the 32 patients survived their surgery and were discharged successfully. Myocardial lactic acid release rate at 80 min after aortic cross-clamping, serum cTnI and CK-MB on the first postoperative day, myocardial mitochondria MDA levels of beating heart group were 13.59%±6.27%,（1.17±0.25） ng/ml, （56.43±16.50） U/L and（2.18±1.23） nmol/（ng.prot）respectively, all significantly lower than those of retrograde perfusion group ［（33.49%±8.29%, （1.82±0.58 ）ng/ml, （78.31±21.27） U/L （5.07±2.35） nmol/（ng.prot），P＜0.05］ and antegrade＋retrograde perfusion group［20.87%±7.22%, （1.49±0.23） ng/ml,（66.67±19.13） U/L,（4.34±1.73） nmol/（ng.prot），P＜0.05］, but not statistically different from those of antegrade perfusion group ［18.83%±5.97%, （1.41±0.32） ng/ml, （63.21±37.52） U/L, （3.46±1.62） nmol/?（ng.prot），P＞0.05］. Conclusion All the four myocardial protective strategies are effective myocardial protection methods for DVR patients. Continuous retrograde perfusion with beating heart and intermittent antegrade perfusion can provide better myocardial protection, and therefore are preferred for DVR patients. The combination of antegrade and retrograde perfusion is easy to administer and does not negatively influence surgical procedures. Retrograde perfusion is also effective as it takes only a short time.
Abstract： Objective To observe myocardial protective effect of sevoflurane used in the whole process of cardiopulmonary bypass（CPB）. Methods A total of 150 patients older than 18 years who underwent cardiac surgery under CPB in Fu wai Hospital from January 2010 to November 2011 were enrolled in this double-blind and randomized controlled study. All the patients were randomly divided into three groups：Sevoflurane pretreatment group （Group A，n=50），whole-process Sevoflurane group （Group B，n=50），and whole-process intravenous anesthesia group （Group C，n=50）. Radial artery pressure and other hemodynamic parameters were continuously measured for all the patients. At following time points: CPB beginning （T1），aortic declamping （T2），3 hours after aortic declamping （T3），and 24 hours after aortic declamping （T4），serum concentrations of cardiac troponin I （cTnI） and other parameters were measured by enzyme-linked immunosorbent assay （ELISA）. Results There were 31 males and 19 females at age of 60.43±3.24 years in group A，28 males and 22 females at age of 59.88±4.12 years in group B，31 males and 19 females at age of 58.76±3.87 years. There was no statistical difference in mean arterial pressure （MAP），central venous pressure （CVP），pulmonary artery wedge pressure （PAWP） and heart rate （HR） at respective time points among the 3 groups （P＞0.05）. At T1 and T2，there was no statistical difference in cardiac index （CI） among the 3 groups （P＞0.05）. At T3，there was no statistical difference in CI between Group A and Group C（F=3.382，P=0.845），but CI of Group B was significantly higher than that of Group A and C（F=3.382，3.382； P=0.033，0.020）. At T4，CI of Group B was significantly higher than that of Group A and C （F=13.324，13.324； P=0.005，P=0.000），and CI of Group A was significantly higher than that of Group C （F=13.324，P=0.024）. At T1 and T2，there was no statistical difference in serum concentrations of creatinine kinase MB （CK-MB），cTnI，interleukin-6 （IL-6） and tumor necrosis factor alpha （TNF-α） among the 3 groups （P＞0.05）. At T3 and T4，serum concentrations of CK-MB，TNF-α，IL-6 and cTnI of Group C were significantly higher than those of Group A，and serum concentrations of CK-MB，TNF-α，IL-6 and cTnI of Group A were significantly higher than those of Group B （F=531.616，5.410，3.5813，3.160，1.126，4.702，7.819，5.424，all P=0.000）. Conclusion Sevoflurane used in the whole process of CPB has definite myocardial protective effect which is ber than that of Sevoflurane pretreatment.
From aortic declamping to weaning from cardiopulmonary bypass (CPB), myocardium needs recovery not only from surgical and ischemia/reperfusion injury, but also of its full performance of pumping function as quickly as possible. In the early period of resuming myocardial perfusion, coronary blood flow should be increased, but ventricular volume overload, large dosage of adrenaline and isoprenaline, and high-energy defibrillation should be avoided. Thenappropriate management according to cardiac function and ECG changes is needed for successful weaning from CPB.