Long-term heart preservation using a new portable hypothermic perfusion apparatus

Combined Assessment of Functional and Metabolic Performance of Human Donor Hearts: Possible Application in Donation After Circulatory Death

BACKGROUND

Donation after circulatory death (DCD) represents an increasing source of organs. However, evaluating the suitability of DCD hearts for transplantation represents a challenge. Contractile function is the ultimate determinant of recovery. We developed a novel technique in an ex vivo rig for the measurement of contractility using intraventricular balloons. We compared this technique with the measurement of lactate metabolism, the current gold standard.

METHODS

Human DCD (n = 6) and donation after brain death (n = 6) hearts were preserved by perfusion with a cold oxygenated crystalloid solution for 4 h, transferred to a blood perfusion rig at 37 °C where balloons were inserted into the left (LV) and right (RV) ventricles to measure developed pressure (DP = systolic minus diastolic). Perfusate lactate levels were measured for metabolic assessment. Concordance between LVDP and lactate was assessed during 4 h using cutoffs for LVDP of 70 mm Hg and for lactate of 10 mmol/L.

RESULTS

Measurements of contractile function (LVDP) and metabolism (lactate levels) were deemed concordant in 7 hearts with either a high LVDP (mean 100 mm Hg) with low lactate (mean 6.7 mmol/L)) or a low LVDP (15 mm Hg) with high lactate (mean 17.3 mmol/). In the remaining 5 hearts, measurements were deemed discordant: 4 hearts had high LVDP (mean 124 mm Hg), despite high lactate levels 17.3 mmol/L) and 1 had low LVDP (54 mm Hg) but low lactate (6.9 mmol/L).

CONCLUSIONS

The intraventricular balloon technique provides useful information regarding contractile recovery of donor hearts that if combined with lactate metabolism has potential application for the evaluation of DCD and marginal donation after brain death hearts before transplant.

Subzero 12-hour Nonfreezing Cryopreservation of Porcine Heart in a Variable Magnetic Field

BACKGROUND

A novel subzero nonfreezing heart preservation method has been developed. It uses a refrigerating device that generates a variable magnetic field, allowing the whole organ to be cooled simultaneously to a supercooled state without the use of cryoprotectant. As a fundamental experiment for heart preservation, we verified whether this novel method is able to suppress anaerobic metabolism and reduce damage in the hearts of large animals.

METHODS

Twelve porcine hearts were collected and preserved for 12 hours using a simple immersion method. The hearts were divided into 2 groups: 6 underwent nonfreezing preservation at -3°C in a variable magnetic field (subzero group), and 6 underwent conventional preservation at 4°C (conventional group). The quantity of anaerobic metabolism and the degree of ultrastructural change in the 2 groups were evaluated and compared.

RESULTS

The concentration of adenosine triphosphate in the myocardial tissue was significantly greater in the subzero group than in the conventional group (21.06±5.87 μmol/g vs 5.96±3.41 μmol/g; P < 0.05). The accumulated lactate concentration was significantly lower in the subzero group than in the conventional group (6.58±2.28 μmol/g vs 11.15±3.74 μmol/g; P < 0.05). The Flameng score, an index of ultrastructural changes to the mitochondria, was significantly lower in the subzero group than in the conventional group (1.28±0.40 vs 2.73±0.30; P < 0.05).

CONCLUSIONS

Subzero nonfreezing preservation using a variable magnetic field resulted in a remarkable suppression of anaerobic metabolism and myocardial protection in porcine hearts.

Low-flow perfusion preservation versus static preservation for isolated rat heart: effects on recovery of myocardial function

BACKGROUND

Clinically, donor hearts cannot be preserved for >6 hours between explantation and recipient implantation. A better approach is needed to preserve donor hearts for a longer time. We tested whether low-flow perfusion (LFP) could satisfactorily preserve isolated rat hearts with histidine-tryptophan-ketoglutarate (HTK) solution or Fuwai modified (FWM) solution.

METHODS

We divided 32 male Sprague-Dawley rats randomly into 4 groups (n = 8): H1, H2, F1, and F2. The Langendorff heart model immersed isolated hearts in the H1 and F1 groups in HTK or FWM solution for 8 hours at 4 °C. Isolated hearts in the H2 and F2 groups were low-flow perfused with HTK solution and FWM solution for 8 hours at a pressure of 10 cmH(2)O at 4 °C. After 60 minutes reperfusion, we measured recovery of cardiac function, myocardial water content, and leakage of myocardial enzymes.

RESULTS

After reperfusion, no cardiac rebeating was observed among F1 group hearts; in addition, they showed significantly higher myocardial water content and lactate dehydrogenase leakage compared with the other 3 groups (P < .05). The recovery rates of cardiac function among H2 hearts were better than the other 3 groups (P < .05); their myocardial water content and enzyme leakage were less than the other 3 groups (P < .05).

CONCLUSIONS

Hypothermic LFP was better than static storage to preserve isolated rat hearts. HTK solution afforded better myocardial protection than FWM.

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

Donor hearts cannot be preserved beyond 6h 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 (8h) 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 8h at 0-4°C (CS group, n=6) or were continuously perfused with oxygenated blood cardioplegia at 26°C for 8h (CP group, n=6). After preservation, hearts were transplanted into recipients and reperfused for 3h. 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.

Preserving and evaluating hearts with ex vivo machine perfusion: an avenue to improve early graft performance and expand the donor pool

Cardiac transplantation remains the first choice for the surgical treatment of end stage heart failure. An inadequate supply of donor grafts that meet existing criteria has limited the application of this therapy to suitable candidates and increased interest in extended criteria donors. Although cold storage (CS) is a time-tested method for the preservation of hearts during the ex vivo transport interval, its disadvantages are highlighted in hearts from the extended criteria donor. In contrast, transport of high-risk hearts using hypothermic machine perfusion (MP) provides continuous support of aerobic metabolism and ongoing washout of metabolic byproducts. Perhaps more importantly, monitoring the organ's response to this intervention provides insight into the viability of a heart initially deemed as extended criteria. Obviously, ex vivo MP introduces challenges, such as ensuring homogeneous tissue perfusion and avoiding myocardial edema. Though numerous groups have experimented with this technology, the best perfusate and perfusion parameters needed to achieve optimal results remain unclear. In the present review, we outline the benefits of ex vivo MP with particular attention to how the challenges can be addressed in order to achieve the most consistent results in a large animal model of the ideal heart donor. We provide evidence that MP can be used to resuscitate and evaluate hearts from animal and human extended criteria donors, including the non-heart beating donor, which we feel is the most compelling argument for why this technology is likely to impact the donor pool.

Benefits of Perfusion Preservation in Canine Hearts Stored for Short Intervals

BACKGROUND

Continuous perfusion of donor hearts for transplantation has been proposed to improve graft function or extend preservation intervals, but the effects on cellular metabolism, myocyte loss, and myocardial edema are not well-defined.

METHODS

Hearts from mongrel dogs were instrumented with sonomicrometry crystals and left ventricular (LV) catheters. LV function was quantified by the preload-recruitable stroke work (PRSW) relationship. Hearts were arrested with a modified Celsior solution, and stored in cold solution (n=6) or placed in a device providing continuous perfusion of this solution at 10 mL/100 g/min (n=6). After 4 h of storage, left atrial samples were frozen, extracted, and analyzed by magnetic resonance spectroscopy (MRS). Hearts were then transplanted into recipient dogs and reperfused for 6 h with function measured hourly. At end-experiment, LV specimens were assayed for water content and apoptosis. Serum CK-MB levels were measured.

RESULTS

LV functional recovery was excellent in both groups over 6 h of reperfusion. MRS revealed a dramatic decrease in tissue lactate in hearts protected with continuous perfusion (P<0.01). Apoptotic cell counts were significantly lower in post-reperfusion heart tissue in animals undergoing a continuous perfusion strategy (P<0.01). CK-MB levels and LV water content were similar in both groups.

CONCLUSIONS

Although both methods of preservation lead to good early graft function after 4 h of protected ischemia, continuous preservation dramatically reduces tissue lactate accumulation without increasing myocardial edema and may reduce tissue damage during storage and reperfusion. It appears promising as a method to improve results of cardiac transplantation.

Use of diffusion tensor imaging to predict myocardial viability after warm global ischemia: possible avenue for use of non-beating donor hearts

BACKGROUND

The assessment of myocardial viability after global warm ischemia (WI) but before reperfusion is challenging. We hypothesized that fractional anisotropy (FA), a magnetic resonance imaging (MRI) parameter of water diffusion that characterizes cellular integrity within tissues, provides a rapid and useful method for evaluating the viability of hearts after WI.

METHODS

Dog hearts were exposed to 60 minutes of WI after exanguination, explanted and preserved in a cold, non-beating state for 6 hours, using continuous perfusion (CP) or static cold storage (CS). Toward the end of preservation, a global FA assessment, acquired using MRI, was compared with analyses obtained from myocardial biopsies that included adenosine triphosphate (ATP), endothelin-1 (ET-1) and caspase-3 levels, light microscopy and tetrazolium staining. Functional recovery was analyzed after restoration of blood flow on a non-working Langendorff preparation.

RESULTS

FA measured at the end of CP showed strong correlations with all parameters of functional recovery (developed pressure, R = 0.60; dP/dt, R = 0.96; -dP/dt, R = 0.96). Although FA also correlated with tissue levels of ATP, ET-1 and caspase-3 (R = 0.77, -0.84, -0.64), recovery of myocardial function did not correlate with these markers or any other conventional analyses of myocardial injury (troponin I, changes on light microscopy or tetrazolium staining).

CONCLUSIONS

FA, an MRI-based parameter that indicates cellular integrity, was found to reflect better myocardial ATP stores, less induction of ET-1 and caspase-3 and improved functional recovery of hearts after global WI. As a clinically applicable tool capable of rapidly differentiating reversible from lethal injury, diffusion tensor imaging may prove useful in the eventual adoption of non-beating donor hearts for transplantation.

Attenuation of DNA damage in canine hearts preserved by continuous hypothermic perfusion

BACKGROUND

Continuous hypothermic perfusion is a novel cardiac preservation technique. Reactive oxygen species play a role in ischemia reperfusion injury and limit organ preservation. Oxidative stress mediates a DNA mismatch lesion (7, 8-dihydro-8-oxoguanine [8-oxo-G]), which is repaired by the enzymes MutY homologue (MYH), 8-oxo-G glycosylase (OGG1), and MutS homologue 2 (MSH2). We hypothesized that continuous hypothermic perfusion would allow for maintenance of cardiac function while attenuating myocardial DNA damage with respect to the current clinical practice of static preservation at 4 degrees C.

METHODS

In our canine orthotopic transplant model, donor hearts were harvested after echocardiograms, and hemodynamic studies were obtained and served as controls. The hearts were transplanted after 24 hours of continuous hypothermic perfusion or 4 hours of static preservation, and were studied for 6 hours. Quantification of 8-oxo-G lesions, MYH, OGG1, and MSH2 concentrations were performed on biopsies using immunohistochemistry.

RESULTS

Postimplant echocardiograms, completed in 7 continuously perfused and 8 statically preserved hearts, demonstrated good function and normal wall motion. Positive staining for 8-oxoG was markedly increased in the static preservation group. Staining density for MYH, OGG1, and MSH2 were significantly decreased in statically preserved hearts and equivalent between continuously perfused and control hearts.

CONCLUSIONS

The DNA damage assayed by 8-oxoG was significantly increased in statically preserved versus continuously perfused hearts. The DNA repair enzymes MYH, OGG1, and MSH2 were also markedly decreased in the static preservation versus continuous hypothermic perfusion groups. Continuous hypothermic perfusion reduces oxidative damage and extends preservation without compromising function.

A comparative study of long-term heart preservation using 12-h continuous coronary perfusion versus 1-h coronary perfusion following 11-h simple immersion

PURPOSE

We previously reported the superiority of the continuous coronary perfusion method using apparatus developed in our department. However, myocardial edema was a serious problem following this method. The purpose of this study was to attempt a comparative study of 12-h continuous perfusion and 1-h perfusion following 11-h simple immersion to evaluate the suitable method for long-term heart preservation.

MATERIALS AND METHODS

HBD dogs were used in this study. After measuring baseline hemodynamics, cardiac arrest was attained and the coronary vascular beds were washed out with 4 degrees C Celsior solution. The grafts were divided into the two groups. In the CP group (n = 6), the grafts were preserved by continuous perfusion with 4 degrees C Celsior solution, and in the SI + CP (n = 6) group, the grafts were preserved with 11 h of simple immersion followed by an additional 1 h of perfusion with the same solution. The hemodynamics after orthotopic transplantation were compared. We also performed a histopathologic examination.

RESULTS

Hemodynamics after reperfusion were maintained in both groups, and there were no significant differences in CO, Emax, or the rate pressure product between the two groups. In contrast, the percentage water content was significantly lower in the SI + CP group than in the CP group. Histopathologically, the myocytes were well preserved in both groups. However, ischemia-reperfusion changes were observed more frequently in the CP group than in the SI + CP group.

CONCLUSION

A short-term perfusion following the simple immersion method may provide satisfactory results compared to the continuous perfusion method in long-term heart preservation.

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.

Impact of 24 h continuous hypothermic perfusion on heart preservation by assessment of oxidative stress

INTRODUCTION

Despite investigating numerous solutions, additives, and techniques over the last two decades, extending donor heart preservation beyond 4-6 h has not been achieved. Hypothermic heart preservation (HP) induces oxidative stress (OS) with reactive oxygen species (ROS) production, causing DNA cleavage and impairing repair. Quantification of cardiomyocyte concentrations of DNA damage by-products (8-oxoG) and mismatch repair enzymes (MYH, OGG-1, MSH2) reflects the severity of OS. If increased repair enzyme production is insufficient to repair injury, cell death occurs and functional outcomes are impacted. We investigated continuous hypothermic perfusion (CHP), a new form of HP, and the mechanism of injury associated with hypothermic storage, by assessing functional outcome and OS after allotransplantation of canine hearts.

METHODS

Fourteen canine hearts were harvested using standard techniques after baseline echocardiograms and haemodynamic parameters were obtained. The hearts were implanted after 24 h CHP (n = 10) or 4 h static preservation (SP; n = 4). After weaning from cardiopulmonary bypass (CPB), recipients were kept alive for 6 h. Repeat echocardiograms and haemodynamic parameters were obtained. Quantification of MYH, OGG-1, and MSH2 concentrations were performed on biopsies using immunohistochemistry and Western blot analysis.

RESULTS

Twelve out of 14 hearts (8/10 CHP; 4/4 SP) were successfully weaned on moderate inotropic support. Post-implant echocardiogram, completed in 6/10 CHP and 2/4 SP hearts, demonstrated hyperdynamic function and normal wall motion. The expression and activity of DNA repair enzymes was identical between normal baseline and CHP hearts.

CONCLUSION

CHP reduces OS associated with prolonged hypothermic preservation and may allow longer preservation periods without compromising function. CHP offers several potential advantages: (1) resuscitation of non-beating heart donor organs, (2) time for HLA tissue typing, (3) facilitate interventions improving graft function, and (4) increased organ sharing.

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.

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.

Pretransplant rinse of hearts preserved with colloid-free UW solution and more effective heart preservation: studies in a rat abdominal heart transplant model

BACKGROUND

University of Wisconsin solution (UW) provides effective heart preservation under hypothermic conditions, but it can be deleterious at warmer temperatures. Re-warming during the implantation of the graft may be a problem. This study examined the damaging effect of peri-operative warm ischemia in a transplant setting and recovery from such damage. The amelioration of damage by rinsing the graft before re-warming and transplantation was also examined.

METHODS

Rat donor hearts were preserved for 2 hr (0 degrees C) as follows: Series A was preserved with colloid-free UW (MUW), St. Thomas' solution (ST), or calcium-supplemented MUW (MUW+Ca) followed by either transplantation or warming (22 degrees C) for 10 min before transplantation. Series B was preserved with MUW, rinsed with fresh MUW, ST, MUW+Ca, or low-potassium MUW before warming and transplantation. All heart isografts were transplanted heterotopically with an indwelling left intraventricular balloon-tipped catheter. Graft function was measured 1 and 7 days after transplantation.

RESULTS

Grafts re-warmed rapidly during implantation. Function (left ventricular developed pressure, contractility, and relaxation) was significantly and persistently diminished in MUW-preserved grafts subjected to additional warming before transplantation. Preservation with ST was less effective than MUW despite being unaffected by warming. Preservation with MUW+Ca and rinsing with fresh MUW or ST before re-warming allowed recovery of function within 7 days despite significantly diminished function on day 1.

CONCLUSION

This study demonstrated that an increase in the peri-transplant warm ischemic period was detrimental when hearts were preserved with MUW. Preservation with calcium-supplemented MUW or rinsing the heart with fresh MUW or ST before transplantation ameliorated this damage.

Cardiac transplantation following a 24-h preservation using a perfusion apparatus

BACKGROUND

We developed a new apparatus for heart preservation and have already reported successful transplantation following 12 h of preservation using this apparatus. The efficacy of coronary perfusion with an oxygenated Celsior solution was investigated through transplantation following 24 h of preservation using the apparatus.

MATERIALS AND METHODS

After being harvested, grafts were preserved with a combination of immersion in a 4 degrees C Celsior solution and perfusion with an oxygenated Celsior solution using the apparatus in the coronary perfusion (CP) group and simply immersed in a 4 degrees C Celsior solution in the simple immersion(SI) group. beta-Adenosine triphosphate (beta-ATP), phosphocreatine (Pcr), and inorganic phosphate (P(i)) levels and myocardial pH (pH(i)) were measured immediately after the heart was excised and at 12 and 24 h after preservation. Following preservation, orthotopic transplantation was performed. Cardiac function was measured 2 h after weaning from cardiopulmonary bypass (CPB).

RESULTS

beta-ATP/P(i), Pcr/P(i), and pH(i) levels were significantly higher in the CP group than in the SI group at 12 and 24 h after preservation. Four of six animals in the CP group and two of six in the SI group were successfully weaned from CPB. The recovery rates of cardiac function were better in the CP group than in the SI group.

CONCLUSION

Twenty-four hours of heart preservation may be possible with a combination of immersion in a 4 degrees C Celsior solution and perfusion with an oxygenated Celsior solution using the perfusion apparatus.

The Effect of Coronary Perfusion with an Oxygenated Celsior Solution on 12-hour Cardiac Preservation

Celsior is a new extracellular-type cardiac preservation solution. We recently developed an apparatus for preservation using low-pressure continuous coronary perfusion. The purpose of this study was to investigate the efficacy of coronary perfusion with an oxygenated Celsior solution using the new apparatus for prolonged cardiac preservation. Adult mongrel dogs weighing 9-13 kg were divided into two groups: the coronary perfusion group (CP; n = 5) and the simple immersion group (SI; n = 7). The coronary vascular beds were washed out with a 4 degrees C Celsior solution following cardiac arrest using the same solution, and their hearts were excised. In the CP group, the graft was immersed in a 4 degrees C Celsior solution and perfused with the same oxygenated solution. In the SI group, the graft was simply immersed in a 4 degrees C Celsior solution. beta-adenosine triphosphate (beta-ATP), phosphocreatine (Pcr), inorganic phosphate (Pi) levels and myocardial pH (pHi) were measured immediately after excising the heart, and at 3, 6, and 12 hours after preservation. beta-ATP, Pcr, and Pi values were expressed as a percentage of control values, which were measured immediately after excising the heart. beta-ATP/Pi and Pcr/Pi levels were significantly higher in the CP group than in the SI group at 6 and at 12 hours after preservation. The pHi levels during preservation were significantly higher in the CP group than in the SI group. Low-pressure hypothermic coronary perfusion with an oxygenated Celsior solution is effective for long-term heart preservation. </hea