A method for an ex situ operation of the liver is presented with the example of such an operation in a 40-year-old patient. With this operation bilateral liver metastases of a leiomyosarcoma--which were otherwise regarded as irresectable--were resected. Function of the liver after reimplantation was good. Liver protection was performed by perfusion with cardioplegic HTK-solution (Bretschneider). The techniques of liver ex- and implantation are based on the methods of liver transplantation. Extracorporal femoro-porto-axillary bypass for decompression of the inferior caval vein and portal vein was used throughout the anhepatic period of 6 h. It is supposed that the method described here--which according to the authors' knowledge has been performed for the first time in a patient--will open up new perspectives for the surgery of malignant and occasionally of benign tumors, if necessary also for other surgical liver diseases. As an additional possibility, in situ protection of the liver with consecutive operation of the bloodless liver in situ is discussed. This procedure will correspond for the most part to the ex situ technique described here.

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Since intermittent cardioplegic reperfusion during an ischemic period may reduce the ischemic stress of the heart at least by lowering myocardial temperature, we compared the post-ischemic recovery of the dog heart following cardioplegia and subsequent continuous ischemia of 1 X 300 minutes at 22 +/- 1 degree C (model 1) and following cardioplegia and subsequent 3 X 100 minutes of ischemia at 17 +/- 1 degree C with intermittent 4-minute cardioplegic reperfusion every 100 minutes (model 2). The parameters of post-ischemic recovery were the cardiac O2 consumption per beat at work (MVO2-E0): HR), the stability of cardiac rhythm, the left ventricular content of high-energy phosphates, and ultrastructure. Solution HTK with a magnesium concentration of 9 mM/L, in clinical use up to the beginning of 1984, resulted in a significantly better post-ischemic recovery in model 1, despite about 40% lesser ischemic stress in model 2. A reduction of Mg concentration from 9 to 4 mM/l, as in the HTK solution clinically tested since February 1984, did facilitate the post-ischemic recovery in model 1 as indicated by the stability of cardiac rhythm but led to a significant improvement of all parameters of recovery in model 2. Moreover, recovery in model 2 after reduced Mg was also clearly better than in model 1 corresponding to the lesser ischemic stress. The parameters myocardial O2 consumption (MVO2) and potassium loss during HTK perfusion containing 9 and 4 mM/l, respectively, gave indications of specific membrane labilizing effects of Mg in the cardioplegic solution HTK.

Preischaemic doubling of the myocardial buffer capacity optimizes the energy supply of the ischaemic heart by anaerobic glycolysis. For osmotic reasons this method of improving ischaemia tolerance can only be realized in combination with cardioplegia by extracellular Na+ and Ca2+ reduction. The cardioplegic solution 'HTK' which has been developed according to these considerations. (1) delays the decay velocity of myocardial ATP by a factor of 7-8 in comparison with pure ischaemia; (2) leads to a good myocardial recovery with regard to metabolic, morphological, and functional criteria after an ischaemic stress of 300 min at 23 +/- 1 degrees C--especially after the addition of quinine; (3) is considerably reduced in its protective efficacy by adding 50 mumol l-1 Ca2+; (4) causes a calcium paradox if it is infused for 30 min at 35 degrees C; this does not happen if it is infused for 60 min at 25 degrees C or for 120 min at 15 degrees C; on adding 50 mumol l-1 Ca2+ to the solution the risk of a calcium paradox is significantly reduced, even after infusion for 35 min at 35 degrees C; (5) effects an evident delay of recovery, if a continuous ischaemic stress of 300 min at 23 degrees +/- 1 degree C is reduced to 3 X 100 min of ischaemia at 17 +/- 1 degrees C by intermittent cardioplegic reperfusion; (6) considerably improves the myocardial recovery even after intermittent cardioplegia if 50 mumol l-1 Ca2+ are added or Mg2+ is reduced from 9 to 4 mmol l-12. The metabolic, morphological, and functional results are equivalent to those after 300 min of continuous ischaemia. Further investigations must show to what extent the 'membrane stabilizing effect' of [Ca2+]o can be achieved by taking advantage of mutual ionic interaction on the level of plasmalemma (e.g. H+-Mg2+-Ca2+) or by adding membrane effective substances (quinine).