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Recent work has shown that UW may be better than standard cardioplegic solutions for short-term heart preservation. In this study we have used a rabbit heart model to evaluate a simplified UW solution in which penicillin, dexamethasone, insulin, allopurinol, and adenosine were omitted and 5% polyethylene glycol (PEG20M) was substituted for hydroxyethyl starch. The test systems consisted of 4-hr cardioplegic storage at 15 degrees C with repeated flushing every 30 min for 2 hr and 24-hr hypoxic low-flow microperfusion (3 ml/g/24 hr) at 0 degrees C. Control groups were arrested with a 15-25 ml flush in iced saline and immediately tested. Cardiac output (CO)* after preservation was measured in a working heart model using an acellular perfusate at 37 degrees C at an aortic pressure of 100 cm H2O. The CO (ml/g heart wt/min) were as follows--Controls: St. Thomas II 20.5 +/- 8.3 (5), UW 34.7 +/- 11.7 (16), PEG20M 41.8 +/- 4.4 (14); 4-hr cardioplegia: St. Thomas II 17.4 +/- 0.9 (4), Bretschneider HTK 14.9 +/- 7.0 (4), UW 25.2 +/- 11.5 (9), PEG20M 41.1 +/- 7.8 (8); 24-hr microperfusion: UW 25.4 +/- 11.1 (18), PEG20M 37.1 +/- 8.2 (18). Following cardioplegic or microperfusion preservation, PEG20M hearts functioned at control levels (P greater than 0.05) and were significantly superior to all other solutions, with approximately double the CO (P less than 0.05, all other groups). We conclude that for heart preservation, 5 components can be eliminated from UW and substitution of PEG20M for HES appears to have improved its performance.
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PMID:Optimal cardioplegia and 24-hour heart storage with simplified UW solution containing polyethylene glycol. 230 54

Several functional parameters were applied in an experimental model of ischemia to test the ability to localize the distribution of tubular lesions. Canine kidneys were perfused with protective solutions and rendered ischemic for definite periods. Renal function was determined during a subsequent 3-h reperfusion. The pattern and the extent of renal injury were influenced by varying the duration of ischemia and by modifying the protective solution used. The results suggest that by employing an appropriate selection of parameters it is possible to allocate renal injury to definite sections of the tubules. According to such an evaluation, under protection with HTK-solution, the proximal tubule limits the tolerance of renal ischemia. The thick ascending limb shows some vulnerability that is aggravated by disadvantageous modifications of the protective solution and that may become more pronounced in the course of reperfusion. In contrast, more distal parts of the nephron retain a remarkable reserve transport capacity after a tolerable level of ischemia.
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PMID:Postischemic diagnostic localization of tubular lesions. 231 10

In a 40-year old patient multiple liver tumours that were otherwise regarded as irresectable were removed in an ex situ operation--according to the authors' knowledge for the first time in a human. After protective perfusion with a hypothermic HTK solution hepatectomy was performed. After extirpation of the tumours ex situ, the residual liver was re-implanted. The total operation time was 13 h 50 min, the anhepatic period lasted for 6 h 9 min. During the anhepatic period a venous bypass shunted the blood from the a femoral and the portal vein to an axillary vein. Considerable blood loss was balanced by the transfusion of 26 units of banked blood. Severe disturbances of blood coagulation could be avoided by early substitution with fresh frozen plasma, platelets and fresh blood. The long anhepatic phase caused an acidosis that required the application of 330 mVal NaHCC3. In the discussion the necessity for an aggressive intraoperative monitoring of haemodynamic and laboratory parameters is emphasized.
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PMID:[Ex situ surgery of the liver--anesthesiologic management]. 236 Jul 9

In this study, the interstitial space and myocytes were investigated qualitatively and morphometrically in samples from beating, fibrillating as well as from cardioplegically HTK-arrested hearts fixed by immersion or perfusion. The size of tissue clefts separating bundles of myocytes and that of the interstitial space within bundles of myocytes depend on the functional state and on the kind of fixation. Cellular preservation is significantly better in HTK-arrested hearts compared to beating or fibrillating hearts. Thus, for the structural evaluation of myocytes and interstitium, the pretreatment constitutes a highly significant factor.
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PMID:Influence of pretreatment on interstitial and intracellular space of canine left-ventricular myocardium. 236 9

Intracellular pH (pHi) has been measured in human or cat ventricular muscle during 60, 120 and 180 minutes of cardiac arrest by Bretschneider's cardioplegic solution HTK or St. Thomas solution with and without procaine. In 319 control measurements in modified Tyrode's solution pHi (mean, S.D.) was 7.38 +/- 0.02 (n = 128) during the first hour, 7.36 +/- 0.03 (n = 112) during the second hour and 7.35 +/- 0.03 (n = 79) in the third hour. The pHi in right ventricular muscle of the cat and left ventricular human muscle did not differ significantly during the time of measurements (Bretschneider HTK). The values (human/cat) in the first hour were 6.85 +/- 0.03 for both groups, 6.72 +/- 0.04/6.68 +/- 0.04 during the second hour and 6.70 +/- 0.03/6.67 +/- 0.05 in the third hour of measurement. The values for the St. Thomas solution with/without procaine were 6.83 +/- 0.02/6.74 +/- 0.03 in the first hour, 6.79 +/- 0.02/6.82 +/- 0.04 during the second hour and 6.68 +/- 0.03/6.82 +/- 0.02 in the third hour. An important difference to all other solutions was the observation made under the St. Thomas solution with procaine, that after recovery to normal values pHi decreased between the 2.-5. minute to values of 6.39-6.48 when the preparations were superfused with Tyrode's solution again. No recovery within 1 hour was observed. This fall in pHi was accompanied by a contracture.
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PMID:Intracellular pH measurement during cardiac arrest in ventricular myocardium by Bretschneider's cardioplegic solution HTK and St. Thomas Hospital solution with and without procaine. 243 44

Clinically applied methods of cardioplegia show very different effects on the rapidity of decay of energy-rich phosphates as well as on kind and progression of ultrastructural alterations of the ischemic myocardium. Comparing the methods of cardioplegia according to Kirklin, St. Thomas's Hospital and Bretschneider (solution HTK) with pure ischemia at 25 degrees C (model A) and Kirklin's or St. Thomas's cardioplegia and subsequent 210 min or HTK cardioplegia and 300 min ischemia at 22 degrees C plus 20 min subsequent reperfusion (model B) leads to the following results: Model A: Compared with pure ischemia cardioplegia according to Kirklin and the St. Thomas's Hospital slows down the decay of the left ventricular ATP-concentration by a mean factor of 3 and the progression of structural alterations of the left ventricular subendocardium by a factor of 2. HTK retards the ATP-decay by a factor of 6, the alterations of ultrastructure by a factor of 6.5. St. Thomas's solution, in contrast to all other methods of cardioplegia, at the onset of ischemia already causes a cellular edema of myocytes; the edema increases during ischemia, and at the ATP-concentration of 4 mumol per gram myocardium is more pronounced than with pure ischemia, Kirklin or HTK. After application of Kirklin's solution, in contrast, a cellular edema of capillary endothelia develops during ischemia, which at 4 mumol ATP is more pronounced than with each of the other methods. Model B: After global ischemia until the ATP-concentration of left ventricular myocardium is 4 mumol/g and a subsequent 20 minutes post-ischemic recovery the ultrastructural alterations in principle resemble those occurring during ischemia (model A).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Myocardial protection: left ventricular ultrastructure after different forms of cardiac arrest. 244 33

Four tissue compartments, differing in proton and inorganic phosphate concentration, were resolved by 31P-NMR spectroscopy in samples from dog hearts after cardioplegic treatment with HTK solution. Inversion of the physiological cytoplasmic-mitochondrial pH gradient was observed. The considerable ensuing acidosis of the matrix is discussed with regard to a possible delocalization of ferrous ions.
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PMID:31P-NMR spectroscopy of phosphate compartmentation during ischaemia in hearts protected by cardioplegic treatment. 251 Oct 87

The effects of the cardioplegic solution HTK on membrane potential (EM) and intracellular K and Na activities (aiK, aiNa) were studied in sheep cardiac Purkinje fibres by means of conventional and ion-selective microelectrodes. HTK contains (mM): Na 15, K 10, Ca 0, Mg 4, histidine 180. (1) In control conditions EM was -74.3 +/- 3.3 mV (n = 25), aiK was 116.4 +/- 4.1 mM (n = 7) and aiNa was 8.2 +/- 1.4 mM (n = 15). (2) Exposure to HTK led to a depolarization to -59.7 +/- 3.6 mV (n = 25) which exceeded by about 5-7 mV that induced in a Tyrode solution of 10 mM K and in a modified HTK solution supplemented by 2 mM Ca (n = 6). (3) Addition of 0.5 mM barium eliminated the difference in the steady-state depolarization. (4) HTK superfusion increased aiK to 120.1 +/- 4.4 mM (n = 7) and decreased aiNa to 3.9 +/- 0.9 mM (n = 15). (5) The decrease in aiNa was insensitive to amiloride (1 mM) and to external alkalization but was slightly increased by addition of 2 mM calcium. (6) When the calcium in Tyrode solution was lowered from 2.0 mM to 0.05 mM, aiNa hardly decreased during subsequent exposure to unmodified HTK and it increased in the presence of 0.1 mM dihydroouabain. We propose the hypothesis (1) that the difference in membrane depolarization between HTK and a 10 mM K-Tyrode is caused by a decrease in K conductance by the HTK solution and (2) that the aiNa decline mainly results from a coupled Ca influx via Na-Ca exchange due to a delayed washout of external calcium.
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PMID:The cardioplegic solution HTK: effects on membrane potential, intracellular K+ and Na+ activities in sheep cardiac Purkinje fibres. 251 7

The addition of the disaccharides maltose (10, 20, 30 mM) and sucrose (30, 60 mM) to Bretschneider's organ protective HTK solution was evaluated to improve renal protection by an enhanced glycolytic energy supply. Canine kidneys were perfused for 8 min with either HTK solution or HTK solution containing additional disaccharides. After nephrectomy the kidneys were incubated at 25 degrees C and metabolic parameters were determined at regular intervals. Maltose and sucrose are slowly cleaved during renal ischemia but maltose distinctly faster than sucrose. Maltose increases intraischemic ATP supply. However, 30 mM maltose was no better than 10 mM. 60 mM sucrose was about as effective for glycolysis as 10 mM maltose. However, possibly due to fructose release there was an accelerated decrease of adenine nucleotides with sucrose. Although fructose enters glycolysis it seems to have negative side-effects. Hence, probably neither sucrose nor fructose are appropriate for renal substrate supply during ischemia.
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PMID:Intraischemic metabolic effects of different disaccharides on protected canine kidneys. 251 81

In 12 dogs the hearts after excision were perfused for 24 hours with Bretschneider HTK cardioplegic solution. Six of these hearts were used only to assess myocardial HEP and ultrastructure during 24 hours of conservation. In the next six dogs orthotopic heart transplantation was performed to evaluate functional outcome after prolonged preservation. After 24 hours of continuous perfusion of the donor heart the ATP level was completely comparable with control, preischemic value. Also ultrastructure of the myocytes was perfectly preserved. All transplanted hearts recovered completely upon reperfusion without a need of inotropic support. Good functional outcome after transplantation was correlated with about 70% of myocardial HEP content and intact ultrastructure of the myocytes. We concluded that continuous perfusion with Bretschneider HTK cardioplegic solution makes successful heart transplantation possible after 24 hours of preservation.
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PMID:Successful orthotopic heart transplantation in dogs after 24 hours of continuous perfusion with Bretschneider HTK cardioplegic solution. 251 48


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