| The isolated, working rabbit heart model was used in this study to evaluate effects of Euro-Collins solution (EC) combing microperfusion (MP) for heart preservation. Thirty-two health N.Z. white rabbits weighing 1.9-2.3 Kg were divided into four test groups, n=8 in each group. After hypothermic cardiac arrested, an occlusive cannula was immediately placed in the aorta, and 15ml/Kg of EC solution inflused at 4 C. Then the aorta was tied to a cannula fitted through the lid of a small plastic specimen container. Hearts in experimental groups were perfused at a rate of 5ml/g heart wt/24 hr with the Ecsolution at 4 C for 4-6 hours. Control groups consisted of group A, unstored hearts that had been rapidly removed, cooled and arrested with ice saline, and then functionally evaluated; group B, 6-hour EC-flushed and ice-stored hearts. After the 6-hour preservation period, the aorta and left atrium were cannulated and the hearts were functionlly evaluated at 37 C on an ex-vivo perfusion circuit filled with oxygenated Krebs-Henseleit solution. They were allowed 15 min of recovery while on retrograde Langendorff perfusion at a pressure of 100cmH2O. This was converted to a working heartmode for a 45-min test period during which the LA pressure was kept at 20 cmH2O and the aortic outflow was connected to a column in which the overflow was set at 100cmH2O. Measurements of LVSP, LV dp/dt max, HR and coronary and aortic flow rates were made and recorded at 1 hr, and cardiac output was calculated.Results: The experimental system for isolated perfused working rabbit hearts in this study was stable. Hearts microperfused with EC solution showed excellent function after storage(CO: C-21.38 2.95, D-20.47 3.22 ml/g/min; LVSP: C-13.45 1.49, D-13.67 1.3 Kpa), indistinguishable from unstored controls(CO: 23.94 3.35, LVSP: 14.86 1.2, P>0.05); the damage of myocardiac ultrastructure were slight. However, rather poor function followed simple ice storage with EC for 6 hours without microperfusion (group B). The mean CO and LVSP was 11.51 3.58 and 11.61 1.1(P<0.01 vs. group A, C and D). The damages of myocardiac ultrastructure were serious. Myocardial water content in group A was 85.72 1.83, in group B was 86.39 0.78, in group C was 85.47 1.24 and in group D was 85.45 1.58%. There was no statistically significance difference in myocardiac water content beween the MP groups and control groups.Microperfusion with colloid solution has been shown to be a promising technique for heart preservation. Since the oxygen require will certainly exceed delivery at very low-flow rates, the tissue oxygen tension is likely to be very low regardless of the original pcrfusatc PO2. It avoids the potential for oxidative injury during the storage period. On the other hand, MP mightoffer some support for anaerobic metabolism by provision of substrate, contorl of acidosis, and removal of waste products. In our study, microferfusion with EC solution tested rabbit heartstorage for 6-hour performed significantly better for short periods of rabbit heart preservation than ice storage. It is sure that MP can significant improvement in organ function after preservation; and suggest that acidosis and deposition of waste products were importand factors for reducing heart function after storage.In conclusion, this new technique of microperfusion as a means for heart preservation seems to offer great promise for clinical use.To find an effective method of donor heart preservation for heart transplantation in special circumstance and to improve the heart function after storage, retrograde cold blood cardioplegia combing continuous microperfusion was used for canine donor deart storage in the second part of this study. Distinquishable from simple ice storage with cardioplegia, recipients with retrograde blood microperfusion showed excellent heart function after storage.After experimental and clinical study, we used this technique in three clinical donor heart storage. The in vitro storage time was 146,147 and 180 min. Three donors' h...
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