A comparative study of Celsior and University of Wisconsin solutions based on 12-hr preservation followed by transplantation in canine models

BACKGROUND: Celsior is a recently developed extracellular-type preservation solution that is effective in organ preservation. This experimental study was designed to compare the effects of Celsior and University of Wisconsin (UW) solutions in myocardial protection, using 12-hour preservation followed by orthotopic transplantation. METHODS: Fourteen pairs of adult mongrel dogs were divided into 2 groups. In the UW group (n = 7), UW solution at 4 degrees C was used for coronary vascular washout and storage following cardiac arrest with glucose-insulin-potassium (GIK) solution. In the Celsior group (n = 7), Celsior solution was used to produce cardiac arrest, for coronary vascular washout, and for storage. After 12-hour cold preservation, orthotopic transplantation was performed under cardiopulmonary bypass (CPB). The rate of recovery (%) of cardiac function of donor hearts was compared 1 and 2 hours after weaning from CPB, and then the transplanted hearts were harvested for histological study. RESULTS: Hemodynamic parameters including cardiac output, left ventricular pressure (LVP), and the maximum rates of positive and negative increase of LVP after transplantation were significantly (p < 0.05) higher in the Celsior group than in the UW group 2 hours after weaning from CPB. The transmission electron microscopic study found that degeneration of the mitochondria in the Celsior group was less extensive than in the UW group. CONCLUSION: Celsior solution enhanced the cardiac function of hearts preserved for 12 hours prior to transplantation compared to UW solution. Our results indicate that Celsior solution is equivalent or superior to UW solution for cardiac preservation.     

A new hydroxyl radical scavenger “EPC” on cadaver heart transplantation in a canine model

This study was performed to determine if an “arrested” heart, resuscitated with cardiopulmonary bypass (CPB) after the cessation of beating, can be successfully transplanted, and whether a hydroxyl radical scavenger EPC can reduce ischemic and reperfusion injury during resuscitation of the arrested heart and following orthotopic heart transplantation. A total of 16 pairs of canines were divided into a control group of eight pairs and an EPC-treated group of eight pairs. Cardiac arrest of the donor heart was induced by the discontinuation of respiratory support after the induction of brain death. The cadaver heart was then resuscitated and core-cooled to myocardial temperature of 15°C using CPB. The donor heart was harvested using cold cardioplegia and orthotopically transplanted. All of the transplanted hearts in the EPC group were weaned from CPB without any inotropic support after 60 min of bypass support, whereas all the animals in the control group required 5 μg/kg/min dopamine (P=0.001). Moreover, cardiac function (E _max) 1h after orthotopic heart transplantation was better preserved in the EPC group than in the control group, at 110±36% vs. 70±21% of the post brain death values (P=0.02) These findings demonstrate that EPC reduces posttransplant reperfusion injury, and thus it may prove to be a valuable adjunct in this challenging model.     

The effect of short-term coronary perfusion using a perfusion apparatus on canine heart transplantation from non-heart-beating donors.

BACKGROUND: We investigated the effects of briefly perfusing hearts from non-heart-beating donors (NHBDs) with a Celsior solution before cardiac transplantation. METHODS: Donor hearts were left in situ for 20 minutes after cardiac arrest was induced by rapid exsanguination. Twelve donor-recipient pairs of mongrel dogs were divided into 2 groups, the simple immersion (SI, n = 6) group and the coronary perfusion (CP, n = 6) group. Both groups underwent coronary flushing with Celsior, after which hearts from the SI group were stored using simple immersion for 4 hours and hearts from the CP group underwent 1 hour of further perfusion followed by storage for 3 hours. Orthotopic transplantation was then performed. We measured cardiac output, end-systolic maximal elastance (E(max)), left ventricular pressure, and rate pressure product 1 and 2 hours after weaning from cardiopulmonary bypass (CPB). Two hours after weaning from CPB, the hearts were harvested for histopathologic study and to determine the percentage of water content. RESULTS: The cardiac output (CO) recovery rate was significantly higher in the CP group than in the SI Group 1 hour after weaning from CPB (p < 0.05). The CO recovery rate, E(max), and rate pressure product were significantly higher and the percentage of water content was significantly lower in the CP group than in the SI Group 2 hours after weaning from CPB (p < 0.05). Histopathologic damage was more severe in the SI group. CONCLUSIONS: The results of this study suggest that short-term coronary perfusion with a Celsior solution may be useful for heart transplantation from NHBDs.     

A Non-Heart-Beating Donor Model to Evaluate Functional and Morphologic Outcomes in Resuscitated Pig Hearts

A non-heart-beating donor model was considered to examine whether pig hearts from the abattoir could be resuscitated by whole blood reperfusion. For preservation, machine perfusion using University of Wisconsin (UW) solution was compared with storage on ice. Nineteen hearts from abattoir pigs, harvested 25 &#45 3 min after exsanguination, were harvested and transported to the laboratory. Controls ( n = 7) were immediately reperfused with homologous whole pig blood in an isolated heart model for 60 min with monitoring of left ventricular developed pressure (LVDP), contractility, and coronary flow. UW solution hearts (UW, n = 6) were perfused for 4 h with 10°C cold UW solution before blood reperfusion. In the cold storage group (CS, n = 6), the organs were stored for an additional 4 h on ice before blood reperfusion. In all hearts, histology was performed after 60 min of blood reperfusion to evaluate myocardial reperfusion injury. All three groups showed significant increases in LVDP ( p < .001), although this functional recovery was earliest in the control group and latest in the UW group. Significant declines were observed for both LVDP and contractility from the peak values in each group to the end of blood reperfusion. Coronary flow increased steadily over the time course for the UW group, whereas in the control and CS groups flow increased during the first 15 min of blood reperfusion and then decreased. In the UW and CS groups, there were significant positive correlations between coronary flow and LVDP ( p < .001). Microscopic examination revealed no differences between the three groups. Thus, hearts from an abattoir with 25 min of warm ischemic time can be resuscitated. For storage of these organs, continuous machine perfusion with UW solution is superior to cold storage on ice.     

Multiple organ harvesting from a single donor for transplantation. A comparison of simple cooling technique and bypass technique.

BACKGROUND: We compared a simple, cooling technique to a cardiopulmonary bypass (CPB) technique for multiple organ harvesting (MOH) from a single donor. METHODS: Adult mongrel dogs were divided into three groups. In the in situ cooling group, the aorta and IVC were first clamped and the hepatic and renal vascular beds were washed out with a cold lactated Ringer's solution. In the peritoneal cooling group, hypothermia was induced using an ice slush in the abdominal cavity, and in the CPB group using CPB. As the esophageal temperature reached 25 degrees C, the liver and kidneys were harvested using the same procedure in all three groups. After the splanchnic perfusion, the heart was harvested while it continued to beat. The heart was preserved for 12 hours, and the liver and kidneys for 24 hours in a cold UW solution. Myocardial high-energy phosphates were measured using 31P-MRS, and the hearts were transplanted. Hepatic vascular beds were flushed during preservation, and the effluent was analyzed. Following kidney transplantation, its function was measured. RESULTS: There's no significant difference in myocardial high-energy phosphate or in cardiac function after transplantation. During liver preservation, ALT and LDH levels of the effluent were significantly higher in the in situ group than those in other groups. There's no difference following kidney transplantation. CONCLUSION: The CPB method and peritoneal cooling technique demonstrated stronger early function of hepatic grafts compared with the in situ cooling method. The peritoneal cooling technique is a simpler, safer and more feasible alternative for MOH compared with CPB method, and it may have broad clinical application.     

Continuous perfusion of donor hearts with oxygenated blood cardioplegia improves graft function

Donor hearts cannot be preserved beyond 6 h using cold storage (CS). Improving preservation methods may permit prolonged storage of donor heart. We compared graft function in large animal model after prolonged preservation (8 h) using continuous perfusion (CP) and CS method. Twenty‐four miniature pigs were used as donors and recipients. Donor hearts were either stored in University of Wisconsin solution (UW solution) for 8 h at 0–4 °C (CS group, n = 6) or were continuously perfused with oxygenated blood cardioplegia at 26 °C for 8 h (CP group, n = 6). After preservation, hearts were transplanted into recipients and reperfused for 3 h. Left ventricular (LV) function, cardiac output (CO), malondialdehyde (MDA) and adenosine triphosphate (ATP) levels, and water content were measured. Although water content of CP hearts was higher than that of CS, LV contractility and diastolic function of CP hearts were superior to those of CS. In addition, CP hearts performed better than CS hearts on CO in working heart state. ATP was better preserved and MDA levels were lower in CP hearts compared with those of CS (P < 0.0001). Donor hearts can be preserved longer using continuous perfusion with oxygenated blood cardioplegia and this method prevents time‐dependent ischemic injury.     

Efficacy of an endothelin-A receptor antagonist in heart transplantation from asphyxiated canine non-heart-beating donors

Objective Hypoxic perfusion before arrest, an indeterminate period of warm ischemia, and subsequent reperfusion are major causes of cardiac allograft dysfunction in non-heart-beating donors (NHBDs). The present study was undertaken to elucidate the cardioprotective effects of ET_A receptor antagonist FR139317 for hearts obtained from asphyxiated NHBDs in a canine transplantation model. Methods Hypoxic cardiac arrest was induced in 17 donor dogs. FR139317 (10 mg/kg) was given to 7 of the dogs over a period of 10 min before disconnecting the ventilator. The hearts were preserved with FR 139317-supplemented cardioplegic solution (FR group). The remaining 10 did not receive FR 139317 at any time during the experiment (control group). Orthotopic transplantation was performed after a mean myocardial ischemic time of 4 h. Results During the agonal period, the highest systolic pulmonary artery pressure in the FR group was lower than that in the control group (47 ± 14 vs. 58 ± 27 mmHg). All animals in the FR group were weaned from cardiopulmonary bypass, whereas only five of the controls were weaned, two of which were identified to have dominant right ventricular failure. After transplantation, recovery rates of the left ventricular end-systolic pressure-volume ratio (Emax) and the maximum first derivative of pressure measured over time (max dP/dt) were not significantly different between the groups, but recovery rates of the cardiac index, left ventricular minimum dP/dt and exponential time constant of LV relaxation (tau) in the FR group were higher than those in the control group. Conclusions The ET_A receptor antagonist FR 139317 reduced pressure overload on the right ventricle by decreasing the peak pulmonary artery pressure before donor arrest. Cardioprotective effects of this agent for heart transplantation from NHBDs are manifested by preserved diastolic properties of the left ventricle.     

Orthotopic transplantation of pig hearts harvested after 30 min of normothermic ischemia: controlled reperfusion with blood cardioplegia containing the Na-H-exchange inhibitor HOE 642

Objectives: The aim of our study was to develop a surgical technique for a successful transplantation of hearts harvested after 30 min of normothermic ischemia without donor pretreatment. Successful transplantation of ischemic compromised hearts could help to expand the severely limited donor pool. We used the pig model because this species is very susceptible to myocardial ischemia. Na⁺-H⁺-exchange (NHE) inhibitors have shown excellent protective properties in several in vitro and in vivo models of myocardial ischemia and reperfusion. Methods: In group I (n=12) hearts were harvested after 30 min of normothermic ischemia following cardiac arrest induced by exsanguination. Hearts were perfused with warm blood cardioplegia and transplanted orthotopically. In group II (n=9) controlled reperfusion with cold leucocyte-depleted blood cardioplegia was performed after 30 min of normothermic ischemia. In group III (n=8) the same procedure was performed as in group II but blood cardioplegia contained 1 mmol/l HOE 642. Results: In group I massive myocardial oedema was observed and none of the animals could be weaned from cardiopulmonary bypass (CPB). In contrast, all animals in groups II and III could be weaned from CPB with low dose inotropic support. In groups II and III the contractility of the hearts, expressed as maximal left and right ventricular stroke work index was significantly impaired after transplantation as compared with the preoperative value. Supplementation of blood cardioplegia with HOE 642 resulted in a significantly better recovery of the LVSWImax (Group II vs. III). Conclusions: Successful transplantation of pig hearts is possible after 30 min of normothermic ischemia without donor pretreatment if a controlled reperfusion with cold leucocyte-depleted blood cardioplegia is performed. HOE 642 given during reperfusion only improves posttransplant left ventricular function.     

Cold-inducible RNA binding protein agonist enhances the cardioprotective effect of UW solution during extended heart preservation

In heart transplantation, time restriction is an unavoidable thorny problem during cardiac transport. Cold storage is an important organ preservation method in donor heart transport. Cold-inducible RNA binding protein (CIRBP) has been proven to play a protective role under cold stress. In this study, we investigated the role of CIRBP in hypothermic cardioprotection during heart preservation in UW solution and explored a new approach to extend the heart preservation time. Cirbp-knockout (Cirbp^−/−), Cirbp-transgenic (Cirbp-Tg), and wild-type rats were, respectively, randomized into two groups based on various heart preservation times (6 or 12-hour group) (n = 8 per group). After preservation in UW solution, all hearts were mounted on a Langendorff apparatus and underwent measurement of cardiac parameters, histological analysis, and molecular study. Within the 6-hour preservation group, no significant difference was found in cardiac functions and histological changes between different rat species. However, after 12 hours of preservation, Cirbp^−/− rat hearts showed more apoptosis and worse cardiac function, but less apoptosis and better cardiac function were observed in Cirbp-Tg rat hearts. Furthermore, we found CIRBP-mediated cardiac ubiquinone (CoQ₁₀) biosynthesis plays an important role in extending heart preservation, and ubiquinone biosynthesis protein COQ9 was an essential down-stream regulator during this process. Finally, we found that zr17-2, a CIRBP agonist, could enhance the expression of CIRBP, which further enhances the synthesis of CoQ₁₀ and promotes scavenging of reactive oxygen species and ATP production to extend heart preservation. This study demonstrated that CIRBP-enhanced CoQ₁₀ biosynthesis during hypothermic heart preservation and zr17-2-supplemented UW solution could be a promising approach to ameliorate heart damage and extend heart preservation during cardiac transport.     

A non-heart-beating donor model to evaluate functional and morphologic outcomes in resuscitated pig hearts.

A non-heart-beating donor model was considered to examine whether pig hearts from the abattoir could be resuscitated by whole blood reperfusion. For preservation, machine perfusion using University of Wisconsin (UW) solution was compared with storage on ice. Nineteen hearts from abattoir pigs, harvested 25 +/- 3 min after exsanguination, were harvested and transported to the laboratory. Controls (n = 7) were immediately reperfused with homologous whole pig blood in an isolated heart model for 60 min with monitoring of left ventricular developed pressure (LVDP), contractility, and coronary flow. UW solution hearts (UW, n = 6) were perfused for 4 h with 10 degrees C cold UW solution before blood reperfusion. In the cold storage group (CS, n = 6), the organs were stored for an additional 4 h on ice before blood reperfusion. In all hearts, histology was performed after 60 min of blood reperfusion to evaluate myocardial reperfusion injury. All three groups showed significant increases in LVDP (p <.001), although this functional recovery was earliest in the control group and latest in the UW group. Significant declines were observed for both LVDP and contractility from the peak values in each group to the end of blood reperfusion. Coronary flow increased steadily over the time course for the UW group, whereas in the control and CS groups flow increased during the first 15 min of blood reperfusion and then decreased. In the UW and CS groups, there were significant positive correlations between coronary flow and LVDP (p <.001). Microscopic examination revealed no differences between the three groups. Thus, hearts from an abattoir with 25 min of warm ischemic time can be resuscitated. For storage of these organs, continuous machine perfusion with UW solution is superior to cold storage on ice.     

Myocardial energy metabolism in asphyxiated canine hearts preserved for 24 hours.

Myocardial energy metabolism in asphyxiated cadaver hearts preserved in UW solution (UWS; group 1, n = 6) or modified Collins' solution (MCS; group 2, n = 6) was compared with that in cardioplegic arrested hearts immersed in ice-cold MCS with (group 3, n = 6) or without myoprotective drugs (group 4, n = 5). All hearts were stored for 24 hr. The hearts in groups 1 and 2 were pretreated with prostacyclin, verapamil, and propranolol; asphyxiated for 10 min, reversed by coronary perfusion with warm blood cardioplegia (WBCP); perfused with ice-cold crystalloid cardioplegia for 2 hr; excised and immersed in cold storage solution for 22 hr; and perfused again with WBCP before reperfusion. ATP contents were measured in biopsy specimens by HPLC. Myocardial ATP level decreased significantly from 23.7 +/- 1.7 to 15.9 +/- 2.5 mumol/g dry wt. (P less than 0.0001) by asphyxia, but recovered to within normal limits by WBCP in group 1. The ATP level again decreased to 15.8 +/- 2.4 mumol/g dry wt. during 24-hr storage, but finally rose to 22.4 +/- 3.5 mumol/g dry wt. by terminal WBCP. The ATP metabolism in group 2 was similar to that in group 1. The ATP content in group 4 was significantly lower than that in other groups (P less than 0.01) after 24-hr preservation. The study shows that damage to cadaver hearts can be reversed and the hearts maintained satisfactorily viable for 24 hr.     

Effect of Cardiopulmonary Bypass and Calcium Administration on the Splanchnic Circulation

Gastrointestinal complications following cardiopulmonary bypass (CPB) are associated with high mortality rates. The identification of prolonged CPB time and calcium administration as independent predictors of gastrointestinal complications suggests decreased splanchnic perfusion as a possible mechanism. To test this hypothesis, we evaluated splanchnic organ perfusion during CPB and after calcium chloride administration. Mongrel dogs were studied under anesthesia and were cannulated for bypass. CPB was begun at 37°C, and the heart was fibrillated and vented. After 30 min, CPB temperature was reduced to 25°C for 1 h with the heart arrested through cold crystalloid cardioplegia. After rewarming to 37°C for 30 min, the heart was cardioverted, and CPB was weaned off. Calcium chloride (10 mg/kg) or saline was administered. Organ blood flow was determined with radiolabeled microspheres at baseline, during CPB, and after weaning from CPB. Splanchnic organ blood flow did not decrease during any phase of CPB. Calcium chloride administration after CPB had no effect on splanchnic organ blood flow. While gastrointestinal injury may result from CPB, this study suggests that the mechanism of injury is not decreased by splanchnic organ perfusion during bypass. While calcium chloride can cause pancreatic injury, the responsible mechanism is not calcium-induced hypoperfusion.     

Prolonged preservation of cadaver heart with Belzer UW solution: 24-hour storage system for asphyxiated canine hearts

The efficacy of Belzer UW solution was compared to Collins' solution in the preservation of asphyxiated cadaver hearts in a canine model. Donor hearts were stored for 24 h: 2 h of in situ hypothermic (15 degrees C) coronary perfusion plus 22 h of simple immersion in ice-cold solution. Verapamil, propranolol and prostacyclin were used for myocytoprotection in both groups. After orthotopic transplantation, all animals were weaned off bypass without inotropic support. After 1 h, however, the cardiac output was significantly higher in the Belzer UW solution group (128 +/- 28 vs. 67 +/- 13 ml/kg/min, p less than 0.01).     

常温不停跳心内直视手术冠脉血心肌酶、SOD、GHS及LPO的变化

目的 观察常温沁脏不停跳心内直视手术与冷停跳手术患者冠脉血心肌酶、超氧化物歧化酶（ＳＯＤ）、谷胱甘肽（ＧＳＨ）、脂质过氧化物（ＬＰＯ）的变化，明确不停跳手术对心肌保护作用。方法 ３６例心内直视手术患者随机分成不停跳与冷停跳组，每组１８例。不停跳组分别于体外循环前、体外循环１５分钟、体外循环停止时、机停后３０、６０分钟采血。冷停跳组分别于体外循环前、主动脉阻断时、主动脉开放时、开放后３０、６０分钟采     

The optimal pressure for initial flush with UW solution in heart procurement.

OBJECTIVE: University of Wisconsin (UW) solution is widely used in organ preservation. Some investigators have reported that high pressure during initial flush with UW solution may induce vasoconstriction and endothelial damage, because of its high potassium content and high viscosity. However, using lower pressure during the initial flush may lead to irregular distribution of the solution and incomplete flushing of blood components from coronary vascular beds. This experimental study evaluated the effects of a range of initial flush pressures during heart procurement, followed by orthotopic transplantation of the graft after 12 hours of preservation. MATERIALS AND METHODS: Twelve pairs of adult mongrel dogs, weighing 9 to 14 kg, formed the recipient-donor combinations. After determining hemodynamic status by measuring cardiac output, left ventricular pressure (LVP), and maximum positive and negative change in LVP (+/-LVdP/dt), donor hearts were excised. Coronary vascular beds were flushed with 4 degrees C UW solution at a pressure of 60 mm Hg in the low-pressure group (n = 6) and at 120 mm Hg in the high-pressure group (n = 6). After 12 hours of cold preservation, orthotopic transplantation was performed using cardiopulmonary bypass (CPB). The hemodynamics of the transplanted graft were assessed by comparing recovery rates (%) from donor hearts 2 hours after weaning from CPB. Endothelin-1 (ET-1) levels were measured in the blood obtained from the coronary sinus 30 minutes after reperfusion. The transplanted grafts were then harvested for histologic study and measurement of adenosine triphosphate (ATP) content. RESULTS: Cardiac output, LVP, LVdP/dt and myocardial tissue ATP content were significantly better (p < 0.05) in the high-pressure group than in the low-pressure group. We found no significant differences in ET-1 levels between the groups. Transmission electron microscopic findings revealed that degeneration of the mitochondria was less extensive in the high-pressure group than in the low-pressure group. We observed no obvious ultrastructural damage to the endothelial cells in either group. CONCLUSION: When using UW solution in heart procurement, high pressure is better to completely wash out the blood components and distribute the solution.     

Thromboxane A2 receptor blockade improves contractile function following cardiopulmonary bypass in dogs and pigs.

Thromboxane A2/prostaglandin endoperoxide (TP) receptor antagonists have been reported to decrease the extent of myocardial damage after coronary ligation. The purpose of this study was to determine if the TP antagonist SQ 30,741 can protect myocardial tissue during cardiac arrest and cardiopulmonary bypass (CPB) in dogs and pigs. In the first part of the study, anesthetized dogs were subjected to normothermic CPB (37.5 degrees C) at a flow rate of 2 liters/m2/min. Dogs were treated with either 5 mg/kg + 5 mg/kg/hr SQ 30,741 or vehicle starting before CPB. The aorta was cross-clamped for 25 min and then released to allow reperfusion. In another study, pigs had hypothermic (28 degrees C) CPB but with arrest for 1 hr. Myocardial recovery was assessed by segment shortening as determined by sonomicrometry. Canine hearts treated with SQ 30,741 had a significantly improved reperfusion contractile function such that at 60 min postreperfusion, segmental shortening returned to 96% of pre-bypass levels vs 70% in vehicle-treated controls (P less than 0.05). In pigs, 70% of vehicle-treated pigs could not be weaned off CPB and died. All six pigs treated with SQ 30,741 survived. SQ 30,741 prevented platelet loss in dogs, but did not in pigs. Thus, SQ 30,741 significantly improved reperfusion function in hearts subjected to CPB.     

Long-term preservation using a new apparatus combined with suppression of pro-inflammatory cytokines improves donor heart function after transplantation in a canine model.

OBJECTIVE: We developed a new apparatus for long-term heart preservation that combines simple immersion with coronary perfusion. In a previous study, we reported that suppression of pro-inflammatory cytokines, such as tumor necrosis factor alpha (TNF-alpha) and interleukin-1beta (IL-1beta), improved results after transplantation. In this study, we evaluated whether long-term preservation using our apparatus for continuous coronary perfusion, combined with suppression of pro-inflammatory cytokines, improves donor heart function after transplantation in a canine model. METHODS: We used adult mongrel dogs in this study. Coronary vascular beds were washed with University of Wisconsin (UW) solution after arresting hearts with glucose-insulin-potassium solution. The heart was then excised and preserved for 12 hours with a combination of immersion and coronary perfusion using a preservation apparatus. Adult mongrel dogs were divided into 2 groups: the coronary perfusion (CP) group (n = 7) and the FR167653 (FR-CP) group (n = 6). In the CP group, we used a 4 degrees C UW solution for immersion and coronary perfusion. In the FR-CP group, we used a 4 degrees C UW solution supplemented with 20 mg/liter of the anti-inflammatory agent FR167653 for immersion and coronary perfusion. At 2 and at 3 hours after orthotopic transplantation, we compared hemodynamic parameters with pre-operative values in donor animals, with right atrial pressure at 10 mm Hg and with 5 microg/kg/min dopamine infusion. We compared serum concentrations of TNF-alpha from the coronary sinus and compared electron microscopic studies between the 2 groups. RESULTS: Three hours after transplantation, cardiac output (CO), left ventricular pressure (LVP), and -LVdp/dt were significantly greater (p < 0.05) in the FR-CP group than in the CP group (CO, 178% +/- 65% vs 93% +/- 40%; LVP, 115% +/- 22% vs 73% +/-26%; -LVdp/dt, 168% +/- 13% vs 61% +/- 17%, respectively). Electron microscopic studies showed that glycogen was well preserved in the FR-CP group compared with the CP group. Serum concentrations of TNF-alpha were decreased significantly in the FR-CP group compared with the CP group at 3 hours after reperfusion (161 +/- 54 pg/dl vs 642 +/- 636 pg/dl, respectively). CONCLUSION: Hemodynamics after transplantation were significantly better in the FR-CP group than in the CP group. The combined preservation method of continuous perfusion and immersion using our apparatus in conjunction with suppression of pro-inflammatory cytokines improves donor heart function after transplantation.     

Intermittent warm blood cardioplegia —An experimental study—

The influence of intermittent warm blood cardioplegia (WBCP) on myocardial function and metabolism was studied. Fourty-two adult mongrel dogs were used. The isolated heart of one dog was perfused by the cross circulation method with another support dog. The dogs then were divided into three groups. In group I (n=6), the empty beating heart was perfused with warm blood (WB) kept at 36°C for 100 minutes. In group II (n = 7), the arrested heart was perfused with continuous WBCP using modified Fremes solution for 100 minutes. In group III (n=8), the arrested heart was perfused with WBCP for 10 minutes following a 15-minute non-perfusion period. This perfusion method was repeated four times. The E max, LV developed pressure, ± LV dp/dt and LVEDP were all measured to evaluated the myocardial function. In addition, the coronary venous blood pH, myocardial oxygen consumption, myocardial lactate extraction, coronary blood flow, myocardial high energy phosphate content and myocardial water content were also studied in order to elucidate the myocardial metabolism. Regarding the myocardial function, no significant difference was observed between the three groups. The results of chemical studies on the myocardial metabolism were as follows: (1) the coronary venous blood pH in group III decreased at the end of the no perfusion period of WBCP. But it thereafter gradually returned to the normal physiological range; (2) the myocardial oxygen consumption in group III increased just after each interruption, but then gradually decreased toward following intermittent WBCP; (3) the myocardial lactate extraction decreased at the end of the non-perfusion period. However, it gradually returned to the control value by the end of each period of WBCP perfusion; (4) after 60 minutes of reperfusion, the coronary venous blood pH, myocardial oxygen consumption and myocardial lactate extraction showed no significant differences between the groups; (5) the coronary blood flow in group III increased significantly after 1 minute of reperfusion; (6) the ATP value in group III decreased significantly after 60 minutes of reperfusion. The ADP and AMP values demonstrated no significant difference between the groups during the same period; and (7) no significant difference was seen in the myocardial water content between the groups after 60 minutes of reperfusion. It is thus concluded that 10 minutes of intermittent WBCP followed by a 15-minute interruption appeared to have no deleterious effect on the myocardial funciton and metabolism.     

Inhibition of cyclooxygenase-2 improves cardiac function following long-term preservation

BACKGROUND: Cyclooxygenase (COX) is an intracellular enzyme that converts arachidonic acid to prostaglandin endoperoxide (PGG(2)). There are two isoforms of COX, namely constitutive COX-1 and inducible COX-2. It has been reported that COX-2 plays an important role in ischemia-reperfusion injury and that COX-2 mRNA and protein expression were up-regulated during cardiac allograft rejection. FK3311 is a suppressor of COX-2 activation. The purpose of this study was to evaluate the effectiveness of inhibiting COX-2 with FK3311 for the minimization of ischemia-reperfusion injury and for the improvement of donor heart function following transplantation in a canine model. MATERIALS AND METHODS: Adult mongrel dogs were used. After the measurement of hemodynamic parameters [cardiac output (CO), left ventricular pressure (LVP), and the maximum rates of increase and decrease in LVP (+/-LVdp/dt)], coronary vascular beds were washed out with a hypothermic (4 degrees C) University of Wisconsin (UW) solution following cardiac arrest in response to cold (4 degrees C) glucose-insulin-potassium solution. The heart was then excised and preserved in hypothermic (4 degrees C) UW solution for 12 h. FK3311 (3 mg/kg) was administered intravenously to five dogs prior to reperfusion, while vehicle was administered intravenously to a control group (n = 5). After 3 h of orthotopic transplantation using cardiopulmonary bypass, the hemodynamic parameters were compared with preoperative values of the donor animals under the condition of 10 mm Hg right atrial pressure and 5 mug/kg/min dopamine support. RESULTS: The recovery rates of CO and +/-LVdP/dt were significantly (P < 0.05) higher in the FK-treated dogs than in the controls (CO: 93 +/- 6 versus 66% +/- 4%; +LVdp/dt: 125 +/- 8 versus 77 +/- 10%; and -LVdp/dt: 81 +/- 7 versus 52 +/- 6%; for FK-treated versus control dogs, respectively). The recovery rate of LVP was higher in the FK-treated dogs than in the controls (90 +/- 5 versus 72 +/- 5%), but this difference was not statistically significant. Immunohistochemical staining revealed that COX-2 expression was reduced significantly in the myocardium of FK-treated dogs compared with controls. CONCLUSION: Hemodynamic parameters following transplantation were improved significantly in dogs treated with FK3311. Therefore, the inhibition of COX-2 improves transplanted cardiac function following long-term preservation.     

24-hour rabbit heart storage with UW solution. Effects of low-flow perfusion, colloid, and shelf storage

A new technique for 24-hr cardiac preservation is described utilizing very low flow perfusion (microperfusion) with a cold flush solution. Rabbit hearts were arrested with UW solution and then perfused with the same solution through the aortic root at 0 degrees C at a rate of 3-6 ml/gm heart weight/24 hr. When tested on an ex vivo working heart model, the cardiac output (CO) was 28.72 +/- 7.69 ml/g/min compared with fresh UW flushed controls of 26.48 +/- 2.25 ml/g/min. Both oxygenated highflow perfusion with a more conventional perfusate and 24-hr ice storage with UW led to inferior results. Omission of the colloid, hydroxyethyl starch (HES), from the UW solution or prolonged shelf storage were also significantly detrimental. When a previously untested colloid, polyethylene glycol 20,000, was substituted for HES for microperfusion, excellent cardiac function was obtained. In fact, the mean CO of this group, 31.91 +/- 5.70, was significantly above that of fresh HES-UW unstored controls. The suggestion that the UW solution might be improved by this substitution warrants further study.