Fructose-1,6-diphosphate and a glucose-free solution enhances functional recovery in hypothermic heart preservation.

BACKGROUND: Fructose-1,6-diphosphate (FDP) has been shown to protect tissue during hypoxia under various ischemic conditions, including isolated heart perfusion. We tested the hypothesis that adding FDP to St. Thomas solution can extend hypothermic heart preservation time. METHODS: Sixteen adult Sprague-Dawley rats were used. Under general anesthesia, the hearts were removed and preserved at 4 degrees C in St. Thomas solution (30 ml/kg) for 12 hours. FDP (5 mM) was added to the St. Thomas solution in the study group (n = 8), whereas no FDP was used in the control group (n = 10). The hearts were reperfused after 12 hours of preservation using a working heart model. RESULTS: In the study group, cardiac output ranged from 13.00 +/- 2.34 to 17.66 +/- 1.71 ml/min, maximum aortic flow was 3.40 +/- 1.99 to 9.26 +/- 1.72 ml/min, left ventricular stroke volume ranged from 0.074 +/- 0.014 to 0.092 +/- 0.009 ml, left ventricular stroke work ranged from 6.22 +/- 0.39 to 7.95 +/- 0.44 ml/mmHg, and maximum left ventricular generated power was 14.38 +/- 2.94 to 20.16 +/- 2.49 Joules/min. All of these parameters were higher than those in the control group (p < 0.001). Coronary vascular resistance and myocardial tissue wet/dry weight ratio were lower in the study group than in the control group (p < 0.05).CONCLUSIONS: Heart function was better preserved when FDP was added to St. Thomas solution during hypothermic rat heart preservation. The mechanism is not totally clear, but enhancement of high-energy phosphate production during ischemia is possible. Key words: heart, procurement, hypothermia, fructose-1,6-diphosphate.     

Improved lung preservation using a dimethylthiourea flush

The purpose of this study was to evaluate the ability of dimethylthiourea (DMTU), a low molecular weight hydroxyl free radical scavenger, to improve preservation of the lung for transplantation. Following preservation, 15 isolated canine left lower lobes were reperfused for 90 min with autologous blood. Five group I lobes served as controls and were not subjected to ischemia prior to reperfusion. Five group II lobes were flushed and submerged in a cold Euro-Collins solution and stored for 4 hr at 4 degrees C prior to reperfusion. Group III lobes were flushed with a 20 mM DMTU-enhanced Euro-Collins solution, stored for 4 hr, and then reperfused. The isogravimetric method was utilized to determine the capillary permeability coefficient (Kfc) for the reperfused lobes. The Kfc values were 0.10 +/- 0.01, 0.17 +/- 0.01, and 0.10 +/- 0.008 ml/min/mm Hg/100 g lung for groups I, II, and III, respectively (P less than 0.01 II vs I, III). Extravascular lung water values in the reperfused lobe were 4.44 +/- 0.45, 6.57 +/- 0.38, and 5.23 +/- 0.22 ml/g blood free dry lung weight for groups I, II, and III (P less than .05, II vs. I, III). Lung lipid peroxidation, measured as thiobarbituric acid-reactive material, was higher in group II, 146 +/- 6 nmole/g, than in either group I, 90 +/- 5 nmole/g, or group III, 91 +/- 4 nmole/g (P less than 0.01). The results indicate that the addition of DMTU improves hypothermic lung preservation by reducing lipid peroxidation and edema formation upon reperfusion.     

Using fructose-1,6-diphosphate during hypothermic rabbit-heart preservation: a high-energy phosphate study.

BACKGROUND: In this study, we evaluated the effects of fructose-1,6-diphosphate (FDP) on high-energy phosphate metabolism during 18-hour hypothermic rabbit-heart preservation. METHODS: Under general anesthesia and artificial ventilation, hearts from 42 adult New Zealand white rabbits were harvested, flushed, and preserved in St. Thomas solution at 4(o)C for 18 hours. In the study group (n = 15), FDP (5 mmol/liter) was added to the St. Thomas solution, whereas in the control group (n = 17), fructose (5 mmol/liter) was added. Another 10 hearts did not undergo hypothermic storage, but were used as the normal group for high-energy phosphate concentration comparison. RESULTS: After 18 hours of hypothermic preservation, myocardial high-energy phosphate content decreased in both preservation groups. In the study group, left ventricular adenosine triphosphate (ATP) content was 33% of that in the normal hearts, but in the control group, ATP decreased to 14% of normal. Adenosine diphosphate (ADP) content, energy charge, and ATP-to-ADP ratio showed similar decreases. The high-energy phosphate profile (content in the atria and ventricles and the ratio of ATP to ADP to AMP) was maintained in the study group but not in the control group. High-energy phosphate metabolites such as inosine monophosphate (IMP), inosine, and hypoxanthine increased in both preservation groups, but the increase was more prominent in the control group. CONCLUSION: Adding FDP to St. Thomas solution attenuated the depletion of high-energy phosphate concentration in the preserved hearts. This difference was especially prominent in the left and right ventricles. The protective effect of FDP during hypothermic heart preservation deserves further study.     

Distant organ procurement in clinical lung- and heart-lung transplantation. Cooling by extracorporeal circulation or hypothermic flush

The scarcity of suitable donors for single lung and heart-lung transplantation calls for methods of medium-term pulmonary preservation to allow for distant organ procurement. At our institution, the first five grafts (four heart-lung, one single lung) were cooled by means of a transportable extracorporeal circulation unit, while the last eight grafts (four heart-lung, four single lung) were flush-perfused with modified cold Euro-Collins solution. The technique of extracorporated circulation included aortic and right atrial cannulation and cooling to 12 degrees-14 degrees C (rectal temperature) using a bubble oxygenator. Bypass times ranged between 41 and 52 min. Following excision, the organs were transported in ice-cold donor blood for ischemic times from 171 to 310 min. For cold flush preservation, simultaneous coronary (cold St. Thomas's solution) and pulmonary artery perfusion (Euro-Collins solution, 50 ml/kg over 4 min) were initiated simultaneously. The organs were transported in cold Euro-Collins solution for ischemic times of 175 to 270 min. In heart-lung transplantations the first postoperative arterial PO2 upon arrival at the intensive care unit was 120 +/- 38 Torr in the extracorporeal circulation and 140 +/- 38 Torr in the Euro-Collins solution group. Six of eight patients were extubated within 48 h after cardiopulmonary grafting. We conclude that pulmonary function following heart-lung or single lung preservation with simple hypothermic flush is as good or better than that following extracorporeal circulation. Since distant organ retrieval is much more convenient without the latter, preservation using Euro-Collins solution is preferred.     

Influence of different routes of flush perfusion on the distribution of lung preservation solutions in parenchyma and airways.

OBJECTIVE: The present study was performed to investigate the influence of different routes of perfusion on the distribution of the preservation solutions in the lung parenchyma and upper airways. METHODS: Pigs were divided into four groups: control (n = 6), pulmonary artery (PA) (n = 6), simultaneous PA + bronchial artery (BA) (n = 8), and retrograde delivery (n = 6). After preparation and cannulation, cardioplegia solution and Euro-Collins solution (ECS) for lung preservation were given simultaneously. After removal of the heart, the double lung bloc was harvested. Following parameters were assessed: total and regional perfusion (dye-labeled microspheres), tissue water content, PA, aorta, left atrial and left ventricular pressures, cardiac output and lung temperature. RESULTS: Our data show that flow of the ECS in lung parenchyma did not reach control values (9.4+/-1.0 ml/min per g lung wet weight) regardless of the route of delivery (PA 6.3+/-1.5, PA + BA 4.8+/-0.9, retrograde 2.7+/-0.9 ml/min per g lung wet weight). However, flow in the proximal and distal trachea were significantly increased by PA + BA delivery (0.970+/-0.4, respectively, 0.380+/-0.2 ml/min per g) in comparison with PA (0.023+/-0.007, respectively, 0.024+/-0.070 ml/min per g), retrograde (0.009+/-0.003, respectively, 0.021+/-0.006 ml/min per g) and control experiments (0.125+/-0.0018, respectively, 0.105+/-0.012 ml/g per min). Similarly the highest flow rates in the right main bronchus were achieved by PA + BA delivery (1.04+/-0.4 ml/min per g) in comparison with 0.11+/-0.03 in control, 0.033+/-0.008 in PA, and 0.019+/-0.005 ml/min per g in retrograde group. Flows in the left main bronchus were 0.09+/-0.02 ml/min per g in control, 0.045+/-0.012 ml/min per g in PA, and 0.027+/-0.006 ml/min per g in retrograde group. The flow rates were significantly (P = 0.001) increased by PA + BA delivery of the storage solution (0.97+/-0.3 ml/min per g). CONCLUSIONS: Our data show that the distribution of ECS for lung preservation is significantly improved in airway tissues (trachea and bronchi) if a simultaneous PA + BA delivery is used.     

Equivalent eighteen-hour lung preservation with low-potassium dextran or Euro-Collins solution after prostaglandin E1 infusion.

Improved techniques of pulmonary preservation would help alleviate the critical shortage of donor organs in lung transplantation and would improve early graft function. A previous study demonstrated that cold pulmonary artery flush with low-potassium dextran solution was superior to Euro-Collins solution in preservation of canine lung allografts stored for 12 hours when no pulmonary vasodilator was used before donor lung flush. The present study was designed to determine whether donor pretreatment with prostaglandin E1 would affect the superiority of low-potassium dextran as a preservation solution. Prostaglandin E1 was infused (50 micrograms/min) in 12 donor dogs until potent vasodilation was demonstrated. Low-pressure pulmonary artery flush (50 ml/kg) with either Euro-Collins or low-potassium dextran solution (n = 6 for each group) was performed at 4 degrees C in a randomized, blinded fashion. Heart-lung blocks were extracted and stored at 4 degrees C for 18 hours before left lung allografting. Inflatable cuffs were placed around each pulmonary artery, allowing independent study of the native and transplanted lungs. All 12 recipient dogs survived the 3-day assessment period. Lungs flushed and stored in Euro-Collins or low-potassium dextran solution provided equivalent gas exchange function on day 0 (arterial oxygen tension: Euro-Collins 289 +/- 105 mm Hg versus low-potassium dextran 265 +/- 111 mm Hg; mean +/- standard error of the mean) and on day 3 (Euro-Collins 516 +/- 45 mm Hg versus low-potassium dextran 354 +/- 77 mm Hg; p = 0.10). Mean pulmonary artery pressures in the transplanted lung were not significantly different in the Euro-Collins and low-potassium dextran groups on day 0 (21.4 +/- 2 mm Hg versus 33.7 +/- 5 mm Hg, respectively; p = 0.09) or on day 3 (20.2 +/- 2.7 mm Hg versus 24.2 +/- 5.1 mm Hg, respectively; p = 0.50). We conclude that there was no advantage of low-potassium dextran over Euro-Collins as a flush solution in this 18-hour canine single lung allograft model in which prostaglandin E1 was administered before pulmonary artery flush.     

Superior 12-hour heart preservation with pinacidil hyperpolarizing solution compared to University of Wisconsin solution.

BACKGROUND: novel donor heart preservation solution was formulated to produce hyperpolarized arrest with the potassium channel opener, pinacidil. The superior cardioprotective efficacy of this solution has been demonstrated previously when compared to University of Wisconsin solution following 4 hours of hypothermic ischemia. This study tested the hypothesis that pinacidil solution may extend preservation time and provide superior cardioprotective efficacy following 12 hours of ischemia. METHODS: Sixteen rabbit hearts were assigned to receive either pinacidil solution or University of Wisconsin solution in a crystalloid-perfused Langendorff model. Thirty minutes of initial perfusion preceded baseline data acquisition. Left ventricle pressure-volume curves were generated by inflating an intra-ventricular latex balloon. Following cardioplegic administration, hearts underwent 12 hours of hypothermic storage. After 60 minutes of reperfusion, post-ischemic data were acquired. RESULTS: Pinacidil solution demonstrated significantly better myocardial preservation compared to University of Wisconsin solution, with better recovery of developed pressure (53.0 +/- 11.1% vs 20.7 +/- 4.3%, p = 0.017, respectively), post-ischemic coronary flow (55.3 +/- 12.6% vs 23.9 +/- 4.3%, p = 0.034), maximum systolic dP/dT (46.4 +/- 8.3% vs 20.2 +/- 5.1%, p = 0.018) and minimum diastolic -dP/dT (65.3 +/- 10.8% vs 20.2 +/- 5.1%, p = 0.002). Diastolic compliance, expressed as baseline/post-ischemic diastolic slope ratios, was also better preserved by pinacidil solution (0.55 +/- 0.09) vs University of Wisconsin solution (0.40 +/- 0.03) (p = 0.135). CONCLUSIONS: A novel pinacidil solution resulted in improved donor heart preservation during 12 hours of hypothermic ischemia compared to the "gold standard," University of Wisconsin solution. Adopting alternative strategies of hyperpolarized arrest may allow extension of preservation time beyond the limits of traditional depolarizing solutions.     

Myocardial protective effect of human recombinant hepatocyte growth factor for prolonged heart graft preservation in rats

BACKGROUND: In heart transplantation, myocardial apoptosis during hypothermic storage contributes to graft dysfunction. On the other hand, hepatocyte growth factor (HGF) has been reported to be an antiapoptotic factor in the heart. Therefore, we assessed whether the administration of recombinant human HGF (rh-HGF) prevents apoptosis in the prolonged preserved myocardium, resulting in an improvement in the cardiac function of the graft. METHODS: Isolated rat hearts were subjected to 4 hr (group A), 6 hr (group B), and 8 hr (group C: without rh-HGF vs. group D: with 100 microg of rh-HGF) of hypothermic storage followed by 60 min of normothermic reperfusion (n=5 in each group). RESULTS: Compared with non-HGF-treated hearts (group C), HGF-treated hearts (group D) showed a significantly higher recovery rate of left ventricular developed pressure (38+/-5% vs. 58+/-6%, P<0.01) and maximum dp/dt (53+/-7% vs. 74+/-4%, P<0.01) and a lower rate of TUNEL-positive cardiomyocytes (7.8+/-6.0% vs. 25.3+/-8.9%, P<0.05) after 60 min of reperfusion. Western blot analysis revealed that c-Met/HGF receptor expression was stronger in the HGF-treated myocardium than in the non-HGF-treated myocardium after 8 hr of storage and was associated with a weaker expression of caspase-3 and a stronger expression of Bcl-xL after 60 min of reperfusion. CONCLUSION: The administration of rh-HGF before storage improved cardiac function after prolonged myocardial preservation by preventing apoptosis through the c-Met/HGF receptor. Thus, the addition of rh-HGF in the storage solution may be a promising strategy for prolonged heart graft preservation.     

Microperfusion techniques for long-term hypothermic preservation.

BACKGROUND: The aim of this study was to compare several methods of hypothermic heart preservation. METHODS: We preserved isolated pig hearts for 24 hours in cold cardioplegia (4 degrees C), using either continuous microperfusion (Group I) or simple storage (Group II), and with a new preservative solution (NPS, groups IA and IIA) vs St. Thomas' solution (groups IB and IIB). The main characteristics of the NPS include (1) prevention of cell swelling with polyethelene glycol (PEG), (2) low calcium and magnesium, and (3) presence of metabolic substrates, such as glucose, insulin, pyruvate, aspartate, alanyl-glutamine, and membrane stabilization compounds such as ethanol and chlorpromazine. RESULTS: The 4 above groups were compared with hearts harvested and immediately reperfused (control group). During preservation, only Group IB showed significant edema (40% +/- 8.4% water gain). Adenylate charge was 25% to 50% higher in microperfused Groups IA and IB (0.678 +/- 0.049 and 0.795 +/- 0.071, respectively) as compared with simple-storage groups IIA and IIB (0.605 +/- 0.048 and 0.524 +/- 0.160, respectively). Ultrastructural analysis showed that tissue injury occurred mainly in Group IIB (altered mitochondria, chromatin clumping). Functional data showed better recovery of NPS groups as compared with St. Thomas groups: coronary flow was identical in Group IB and control (57.8 +/- 22 and 56.6 +/- 14 ml/min/100 g, respectively), and in IA > IB (p < 0.001) and IIA > IIB (p < 0.01); the rate pressure products were higher in NPS groups compared with St. Thomas groups (IA > IB, p < 0.01); IIA > IIB, p < 0.05). CONCLUSIONS: The microperfusion method associated with the NPS provides excellent protection in long-term hypothermic heart preservation.     

Long-term myocardial preservation: beneficial and additive effects of polarized arrest (Na+-channel blockade), Na+/H+-exchange inhibition, and Na+/K+/2Cl- -cotransport inhibition combined with calcium desensitization

BACKGROUND: Polarized arrest, induced by tetrodotoxin (TTX) at an optimal concentration of 22 micromol/L, has been shown to reduce ionic imbalance and improve myocardial preservation compared with hyperkalemic (depolarized) arrest. Additional pharmacologic manipulation of ionic changes (involving inhibition of Na+ influx by the Na+/H+ exchanger [HOE694] and Na+/K+/2Cl- cotransporter [furosemide], and calcium desensitization [BDM]) may further improve long-term preservation. In this study, we (i) established optimal concentrations of each drug, (ii) determined additive effects of optimal concentrations of each drug and (iii) compared our optimal preservation solution to an established depolarizing cardioplegia (St Thomas' Hospital solution No 2: STH2) used during long-term hypothermic storage for clinical transplantation. METHODS: The isolated working rat heart, perfused with Krebs Henseleit (KH) buffer was used; cardiac function was measured after 20 min aerobic working mode perfusion. The hearts (n=6/group) were arrested with a 2 ml infusion (for 30 sec) of the polarizing (control) solution (22 micromol/L TTX in KH) or control+drug and subjected to 5 hr or 8 hr of storage at 7.5 degrees C in the arresting solution. Postischemic function during reperfusion was measured (expressed as percentage of preischemic function). RESULTS: Dose-response studies established optimal concentrations of HOE694 (10 micromol/L), furosemide (1.0 micromol/L) and BDM (30 mmol/L) in the polarizing (control) solution. Sequential addition to the control solution (Group I) of optimal concentrations of HOE694 (Group II), furosemide (Group III), and BDM (Group IV) were compared with STH2 (Group V); postischemic recovery of aortic flow was 29+/-7%, 49+/-6%*, 56+/-2%*, 76+/-3%*, and 25+/-6%, respectively (*P<0.05 vs. I and V). Creatine kinase leakage was lowest, and myocardial ATP content was highest in Group IV. CONCLUSIONS: A polarizing preservation solution (KH+TTX) containing HOE694, furosemide, and BDM significantly enhanced long-term preservation compared with an optimized depolarizing solution (STH2) used clinically for long-term donor heart preservation.     

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).     

University of Wisconsin solution for pulmonary preservation in a rat transplant model.

University of Wisconsin and modified Euro-Collins solutions for pulmonary preservation were compared in a rat orthotopic left lung isotransplant model. Heart-lung blocks of donor rats were flushed with and preserved in one of the preservation solutions at 0 degrees C. After 6 or 12 hours of cold ischemia, the left lungs were transplanted into recipient rats and reperfused for 1 hour. Pulmonary function was assessed by measuring oxygen and carbon dioxide tensions in arterial blood after removal of the right lung. Lipid peroxide concentrations were measured as thiobarbiturate acid-reactive substances. The ratios of wet to dry weight of grafts after ischemia and after reperfusion were calculated. Histologic changes of ischemia-reperfusion injury of the lung tissue were evaluated using a graded scale. Oxygen tension after 6 hours of preservation followed by reperfusion was significantly higher with University of Wisconsin solution (308.8 +/- 81.1 mm Hg) than with Euro-Collins solution (50.8 +/- 17.8 mm Hg; p less than 0.001). Carbon dioxide tension in the University of Wisconsin solution group was also significantly lower than in the Euro-Collins solution group (28.2 +/- 2.3 versus 46.0 +/- 4.5 mm Hg; p less than 0.05). Lipid peroxide concentration after 6 hours' preservation in University of Wisconsin solution was significantly lower (0.88 +/- 0.07 mumol/g) than that in Euro-Collins solution (1.26 +/- 0.12 mumol/g; p less than 0.05). After 12 hours of preservation only lipid peroxide concentration with University of Wisconsin solution was significantly lower (1.30 +/- 0.09 mumol/g) than with Euro-Collins solution (1.71 +/- 0.15 mumol/g; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Future horizons of lung preservation by application of a platelet-activating factor antagonist compared with current clinical standards. Euro-Collins flush perfusion versus donor core cooling.

With the introduction of platelet-activating factor antagonists, a direct inhibition of ischemia-induced reperfusion injury can be achieved by prevention of platelet activation, reduction of microvascular leakage, and platelet-activating factor-induced bronchoconstriction. At present, two preservation methods are established for clinical lung preservation: (1) donor core cooling by extracorporeal circulation and (2) pulmonary artery flush with Euro-Collins solution and prostacyclin. We compared the quality of organ preservation obtained with these methods to the application of a platelet-activating factor antagonist (WEB 2170; 0.3 mg/kg) for the donor, perfusion solution, and throughout the first 6 hours of reperfusion in combination with prostacyclin (20 ng/kg/min) and Euro-Collins solution (60 ml/kg). Eighteen heterotopic heart and orthotopic left lung transplants were performed in three groups of six dogs each after 6 hours of cold ischemia (group I, donor core cooling; group II, Euro-Collins flush and prostacyclin; group III, Euro-Collins flush, prostacyclin, and WEB 2170). Myocardial preservation was achieved with St. Thomas' Hospital solution (20 ml/kg) in all groups. After transplantation, cardiorespiratory function was assessed at an inspired oxygen fraction of 0.4. After transplantation, superior results were observed in group III, as expressed by significantly improved oxygenation, while cardiac output and pulmonary artery pressures were similar in all groups. We concluded that the use of the platelet-activating factor antagonist WEB 2170 resulted in better lung preservation than current clinical standards.     

Effects of heat stress on metabolism of high-energy phosphates. Comparison of normothermic and hypothermic ischemia.

BACKGROUND: Alterations in metabolic pathways may contribute to the cardioprotective effects of heat stress (HS). We investigated the effects of HS on ATP and phosphocreatine (PCr) levels in the ischemic rat myocardium, after both normothermic and hypothermic ischemia. METHODS: Two protocols were used: (1) normothermic ischemia (20 min at 37 degrees C) with no myocardial protection (n=6 HS; n=6 control); (2) hypothermic ischemia (4 hrs at 4 degrees C) after cardioplegic arrest (n=6 HS; n=6 control). ATP and PCr levels in the heart were measured using 31P nuclear magnetic resonance spectroscopy. RESULTS: At the end of normothermic ischemia, ATP levels were better maintained in HS hearts (C vs HS: 4.51+/-0.66 vs 7.81+/-1.06 micromol/g dry wt+/-SEM, p=0.04). A trend for higher ATP content in HS hearts was observed after 40 min of reperfusion (C vs HS: 11.7+/-1.5 vs 16.9+/-2.0 micromol/g dry wt+/-SEM, p=0.09). PCr content was also higher at the end of 40 minutes of reperfusion in HS hearts (C vs HS: 46.4+/-2.9 vs 56.9+/-3.0 micromol/g dry wt+/-SEM, p=0.03). After prolonged hypothermic ischemia under cardioplegic arrest, heat stress again led to better preservation of ATP levels at the end of ischemia (C vs HS: 5.71+/-0.88 vs 9.23+/-1.38 micromol/g dry wt+/-SEM, p=0.05) and after 40 minutes of reperfusion (C vs HS: 16.8+/-1.4 vs 24.6+/-2.8 micromol/g dry wt+/-SEM, p=0.03). PCr levels were also better maintained at the end of ischemia (C vs HS: 4.87+/-0.77 vs 12.4+/-3.0 micromol/g dry wt+/-SEM, p=0.03) and after 40 minutes of reperfusion in HS hearts (C vs HS: 55.1+/-7.0.vs 79.8+/-7.3 micromol/g dry wt+/-SEM, p=0.03). CONCLUSIONS: Heat stress induces changes in the energy profile of the heart which results in better preservation of ATP and phosphocreatine levels. These changes could be observed after brief normothermic ischemia and also after prolonged hypothermic ischemia under cardioplegic arrest, mimicking conditions of preservation for cardiac transplantation.     

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.     

Twenty-four-hour canine lung preservation using UW solution

The left lungs of 14 mongrel dogs were isolated, preserved, and then reperfused for 120 min. Three groups of lungs were investigated: group 1, nonpreserved lungs (control n = 5); group 2, lungs were flushed with UW solution and cold-stored (4-6 degrees C) in the same flush solution for 24 hr (n = 4); and group 3, lungs flushed and cold-stored with modified Euro-Collins' solution for 24 hr (n = 5). Airway pressure (AWP), static lung compliance (Cst), and pulmonary vascular resistance (PVR) 120 min after reperfusion were significantly higher in group 3 compared with the lungs in group 1 and group 2. AWP was 18.7 +/- 3.9 in group 1, 21.1 +/- 3.8 in group 2, and 33.8 +/- 9.2 ml/cmH2O (mean +/- SD) in group 3 (P less than 0.05). Cst was 14.0 +/- 3.5, 10.8 +/- 1.5, and 6.2 +/- 1.2 ml/cmH2O, respectively (P less than 0.01). Pulmonary vascular resistance was 125 +/- 16, 120 +/- 42, and 410 +/- 108 mmHg/L/min (P less than 0.05). We conclude that UW solution is useful for hypothermic canine lung preservation.     

Poly(ADP-ribose) polymerase inhibition attenuates biventricular reperfusion injury after orthotopic heart transplantation.

OBJECTIVE: Poly (ADP-ribose) polymerase (PARP) activation plays a key role in free radical induced injury in ischemia/reperfusion. We investigated the effects of INO-1001 a novel PARP inhibitor on postischemic myocardial and endothelial function. METHODS: In dogs, 12 orthotopic heart transplantations were performed after 4 h ischemic preservation. At the beginning of reperfusion either saline vehicle (control, n=6), or INO-1001 (1 mg/kg, n=6) was applied. Before explantation and after 120 min of reperfusion we measured biventricular pressure-volume relationships by a combined conductance catheter and the adaptation potential of the right ventricle to acute afterload increase by pulmonary banding. Coronary blood flow (CBF), vasoreactivity, PARP-activation and ATP-content were also determined. RESULTS: INO-1001 led to significantly better recovery of contractility (91+/-3 vs. 44+/-7%, P<0.05) and CBF (44+/-4 vs. 29+/-3 ml/min, P<0.05) and higher increase in CBF after acetylcholine (61+/-10 vs. 27+/-8%, P<0.05). In addition, the inotropic adaptation potential of the right ventricle to an increased afterload was better preserved after INO-1001. ATP content was significantly higher in the INO-1001 group (11.0+/-2.1 vs. 4.5+/-1.1 micromol/g drw). Immunohistology revealed PARP activation in the control group which was abolished by INO-1001 treatment. CONCLUSIONS: PARP inhibition reduces myocardial and endothelial reperfusion injury after orthotopic heart transplantation.     

Reliable thirty-hour lung preservation by donor lung hyperinflation.

We examined the hypothesis that the degree of inflation of the lungs at the time of harvest may have an important role in postpreservation function. Lungs of donor dogs randomly assigned to groups 1 (n = 5) and 2 (n = 5) were ventilated with large tidal volumes (tidal volume, 25 ml/kg; positive end-expiratory pressure, 5 cm H2O; respiratory rate, 12 breaths/min, inspired oxygen fraction 1.0) and were inflated to 30 cm H2O for 15 seconds before pulmonary artery flush and again immediately before tracheal crossclamping. In group 3 (n = 5) donor lungs were normally ventilated (tidal volume, 12.5 ml/kg, positive end-expiratory pressure 0 cm H2O; respiratory rate 12 breaths/min, inspired oxygen fraction, 1.0) and were not hyperinflated before pulmonary artery flushing; the trachea was crossclamped at end-inspiration. In groups 1 and 3 a large bolus (25 micrograms/kg) of prostaglandin E1 was injected into the pulmonary artery before flushing and was also added to the pulmonary artery flush solution (500 micrograms/L). A rapid (approximately 50 seconds), high-volume mm Hg), hypothermic (4 degrees C) pulmonary artery flush was performed in all hypothermic (4 degrees C) pulmonary artery flush was performed in all groups with modified Euro-Collins solution. Heart-lung blocks were stored at 4 degrees C for approximately 29 hours before left single lung allografting. An inflatable cuff was placed around the recipient right pulmonary artery, allowing independent study of the transplanted lung. Hyperinflated lungs harvested with or without prostaglandin E1 provided equivalently excellent early posttransplant function (arterial oxygen tension [mean +/- standard deviation]: group 1; 503 +/- 45, vs group 2; 529 +/- 150 mm Hg; inspired oxygen fraction 1.0). Mean arterial oxygen tension was significantly lower in group 3 (116 +/- 78 mm Hg) than in either groups 1 or 2 (p < 0.0002 for either comparison). Copious reperfusion pulmonary edema was a constant feature in group 3 but was not seen in groups 1 and 2. All 10 recipients in groups 1 and 2 survived the 3-day assessment period without difficulty; two of the five recipients in group 3 died during initial unilateral perfusion of the transplanted lung. Donor hyperventilation and inflation to 30 cm H2O before hypothermic storage can help provide excellent posttransplantation lung function after 30-hour preservation, with or without prostaglandin E1 pretreatment. We speculate that this improvement may be due to effects of increased lung volume on pulmonary vascular tone and/or surfactant metabolism.     

Comparison of UW solution and Euro-Collins solutions for cold preservation of human liver grafts

University of Wisconsin solution, a new organ preservation medium, is reported to extend the period of cold storage. In order to evaluate the efficacy of UW solution in human liver preservation we compared 58 donor liver grafts preserved in Euro-Collins (EC) solution. All livers were harvested in a similar manner. Donor and recipient characteristics in the two groups were comparable. The mean preservation time of the UW solution was 11.5 +/- 4.2 hr (range 3-20 hr), significantly longer than the EC mean preservation time of 4.9 +/- 1.6 hr (2-9.6 hr) (P = 0.0001). Evaluation of mean postoperative liver function tests and coagulation factors on days 1-7 showed no statistical difference between the two groups. There was one primary graft nonfunction in the EC group and none with the UW organs. Hepatic artery thrombosis was similar in each group. The incidence of early retransplantation was similar. Three-month graft survival was 81% in the UW group vs. 73% in the EC group. Patient survival at three months was 87% with the UW organs and 84% with the EC organs. We conclude that cold storage of liver grafts in the UW solution has allowed for significantly longer preservation, permitting transplantation to be performed under semielective conditions and procurement of organs from much further distances. Grafts stored in UW solution perform as well as those stored in Euro-Collins, with no significant difference in liver function abnormalities postoperatively.     

Hypothermic Preservation of the Heart and Lungs with Collins Solution: Effect on Cardiorespiratory Function Following Heart-Lung Allotransplantation in Dogs

The effect of preserving the heart and lungs with hypothermia and Collins solution was studied in 13 mongrel dogs undergoing combined heart-lung transplantation. The five control animals who underwent an immediate transplant following Collins solution perfusion had small increases in extravascular lung water when measured 2.5 hours posttransplant as seen in a previous study. The eight animals who had hypothermic preservation following Collins solution perfusion had significantly higher extravascular lung water than controls (16.3 ± 1.8 ml/kg in preserved animals; 11.2 ± 1.7 ml/kg in controls p < 0.05). The level of lung water reached at 2.5 hours postoperatively was similar to that reached with a previously reported, unacceptable preservation technique. Survival beyond this point was poor due to severe pulmonary edema. We conclude that the use of this solution, given under the experimental conditions which we describe, is not acceptable for hypothermic preservation of the heart and lungs for combined transplantation.