Biomedical subjects
Publications and source records attributed to M J Polonius.
A superior mesenteric vein aneurysm was diagnosed by ultrasound, computed tomography, and angiography in a 55-year-old woman. It was successfully treated by partial resection and reconstruction of the confluent veins.
Tumor growth in a 72-year-old male patient with malignant haemangiopericytoma in the left hemithorax could be followed radiologically for 4 years before symptoms of recurrent hypoglycaemia appeared. The endogenous insulin level in serum was maximally and serum IGF-1 and IGF-2 markedly reduced. An intravenous arginine load test showed a normal stimulation capacity of the pancreatic glucagon secretion but not that of insulin. After resection of the tumor, blood sugar metabolism was completely normalised. The insulin level, IGF-1 and IGF-2 in serum returned to normal.
In cardiac surgery hemofiltration can be used: 1. to balance fluids during ECC, especially in long-term perfusion; 2. to carry out open heart procedures in patients with terminal renal insufficiency; 3. to treat acute hyperkalemia. The model of the 12.5 by 4.5 cm DIAFILTER TM and the model of operation are described. The compounds of the ultrafiltrate (UF) are identical with that of plasma water. Particles with a molecular weight of less than 50,000 can pass freely across the filtration membrane. The filtration capacity is 100 cc/min UF (Q blood: 300 cc/min, pressure across the membrane 600 mm Hg and hematokrit (Hkt) 25%). The technical details of operation are explained. Its general use as well as its simplicity is demonstrated in 10 patients.
At the time of preoperative coronary angiography in 44 patients left ventricular angiograms immediately after high frequency stimulation and after administration of nitroglycerin were performed. For interpretation we used the shortening (in percentage) of 8 vertical semi-diameters and of longitudinal axis in biplane angiograms. The data found in 15 healthy persons were used for comparison. Looking at the rate of shortening after high frequency stimulation myocardial areas endangered by hypoxia could be unmasked. By giving nitroglycerin thereafter we were able to differentiate between reversibly and irreversibly damaged areas. In 7 patients this has already been proven by postoperative examination. In preoperatively reversibly damaged myocardial areas no hypokinesis could be observed any more after successful revascularization. In contrast there was no improvement seen in preoperatively irreversibly damaged areas in spite of graft patency. The described preoperative angiography-test allows: 1. to unmask myocardial areas endangered by hypoxia. 2. to differentiate preoperatively between reversibly and irreversibly damaged areas. 3. more precise indication as well as better control of the results of revascularization.
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In cases of the malfunction of av-fistulae for haemodialyses a kind of prosthetic graft has to be used. Since 1973 alloplastic protheses (Sparks-Mandril) have been used in 7 patients, since 1976 heterologous (Solko-graft-calf-carotis) ones in 12 patients. In an average follow-up period of 18 months the heterologous prostheses proved to be more suitable because of longer patency-rates, simpler handling during surgery and earlier use for dialyses. As a major late complication only one case of an aneurysmatic enlargement was observed in one of the heterologous protheses. Long-term results have still to be waited for.
A better discrimination of phenomenology and severeness of psychopathological disorders after open-heart surgery has been obtained: a) There is no equal distribution of degrees of severeness, a high correlation of severeness with duration of the disorders, a low correlation with age and no dependance of sex. b) Disorientation, clouding of consciousness and disorders of awareness arise earlier, delusions, hallucinations and paranoid ideas tentatively later after surgery. c) Three psychopathological syndromes have been identified. They appear in different frequency, intensity and can be combined.
17 patients, who underwent open heart procedures, were examined during and after standardized exercises at the first, second and third postoperative day. At 10 defined time intervals the following parameters were measured: arterial blood pressure, right and left atrial pressure and in the pulmonary artery, arterial and venous blood gases and cardiac output by thermodilution. Oxygen consumption and cardiac index were calculated. The results show that the majority of patients after open heart surgery are well able to adjust to additional work load even early postoperatively.
UNLABELLED: The Mg++ aspartate-procaine-cardioplegia has been proven in animal experiments as well as from 1970 til 1975 in more than 1000 open-heart-procedures by a myocardial temperature of 32 degrees C and aortic crossclamping time up to 40 minutes superior to all other known procedures of cardiac preservations. To guarantee a safe myocardial protection of the arrested heart for a remarkable longer period of total ischemia, we further developed the cardioplegic technique in the animal lab, and use it now clinically. PRINCIPLE: The arrest is induced by cardioplegia (Mg++ aspartate-procaine), than the arrested heart is cooled down to 15-20 degrees C by cardioplegic coronary perfusion maintaining the oxidative metabolism. The perfusion is stopped. The begin of ischemia is still under normal ATP-levels and continuous cardioplegia. TECHNIQUE: 1. Crossclamping of the aorta; 2. cardioplegic induced cardiac arrest by Mg++ aspartate-procaine (Kirsch); 3. Surface cooling of the heart; 4. Coronary perfusion by hypothermic cardioplegic solution (8-10 min, flow 80-120 ml/min, perfusion pressure maximal 30 mmHg). Perfusate: O2-saturated, erythrocyte free, 6% hydroxyethyl starch solution added 2 mM Mg++ aspartate, 4 mM procaine, 50 mM Na+, 5 mM K+, 0,5 mM Ca++, 25 mM HCO3-, 10 mM glucose, 200 mM mannitol, 250 mg/l 6-methylprednisolone. RESULTS: 84 patients (29 ACVB; 55 valve replacements); crossclamping time: 71 min (SD 22); total time of ischemia: 57 min (SD 18; max 96, min. 27 min); reperfusion time restoring normal excitation-contraction of the heart: 3 min (SD 2); weaning off bypass: 23 min (SD 14). Hemodynamic 12 h postop.: SO2 venous 76% (SD 6). No sympathicomimetics were used. Only 30% of myocardial ATP is splitted after 120 min of cardiac arrest. Electron microscopic findings show only small, reversible alterations of fine structure.
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Some new predictors of postoperative psychosis in open-heart surgery have been identified in a multifactorial study of somatic and psychological factors: Somatic predictors are lower body weight, higher blood levels of urea nitrogen and creatinine, preoperative use of tranquilizers, especially in patients with double valve replacement or congenital heart disease and preoperative cerebral embolism in mitral valve disease. Bypass-time has not proved to be a valid predictor. Psychological predictors are distress provoked by severity and duration of illness, repeated delay of surgery as well as the manner of psychological coping with the illness.
A brief history of the development of coronary heart surgery is presented. Modern methods include the aorto-coronary bypass using saphenous vein graft or the thoracic internal artery, and the resection of ventricular aneurysm. The own experience with a group of 262 patients revealed a total mortality of 11,4%. Selected indication, improved surgical technique and postoperative care changed coronary surgery during the recent years into a routine method. The operative risk is characterized by the anatomical location of the occlusive artery disease as well as by the left ventricular function. But even in the group with high surgical risk the operative treatment is justified since life expectancy under conservative therapy is limited. In a group with 17 late death the main cause was due to cardiac insufficiency. In the group of survivors approximately 84% of the bypass were patent after an average period of 18 months.
From 1970 until 1975 single mitral valve replacement was carried out in 162 patients using Björk-Shiley disc prostheses. The surgical mortality (within 30 days postoperatively) was 9.3% (n=15). Out of these 15 patients 9 died due to myogenic cardiac insufficiency. 21 patients with "Low-output-Syndrome" due to myogenic insufficiency however survived. The improvement of intraoperative myocardial protection since 1972 (using hypothermia and cardioplegic induced cardiac arrest) reduced the frequency of myogenic cardiac insufficiency to 1%. Unrelated to the above mentioned we saw in 18.5% of all patients after ECC-procedures a temporary "Low-output-Syndrome" after the 3rd postoperative day due to pericardial effusion.
From 1972 to 1974 524 patients underwent surgery with extra corporal circulation. 83 (15,8%) patients had to be postoperatively ventilated for a prolonged period or reintubed after a symptomfree interval due to anticipated or manifested complications. 31 (37%) out of these expired. There was no death due to the prolonged ventilation itself, shown by the group, in which the causes for the above treatment were others but respiratory failure or insufficiency. All patients of this group survived. Indications, technique and results are described and discussed.
In 1972 and 1973 there have been 698 (351 with ECC) cardiovascular surgical procedures. 29 cases of renal insufficiency were seen in this group, 15 requiring peritoneal dialysis. There were only two survivors in the latter group. However none died due to renal insufficiency. The indication, technique, complications, results are discussed in detail.
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The risk of open heart surgery can be lowered by combination of different methods of myocardial protection. 1. Cardioplegia with a potassium free Mg-1-aspartate and Procaine-solution (Cardioplegin). 2. Coronary perfusion after ischemia longer than 35-40 minutes in case of excessive left ventricular hypertrophy or failure. 3. Hypothermia. Surface cooling gives an additional safety if coronary perfusion is not ideal possible in case of multiple coronary stenoses. For patients with this dispositions a continuous coronary perfusion with cardioplegic solution might be advisable, as it was presented by Gercken in his paper. This method was used three times already in human, but is still in an experimental stage.