Thoraxchirurgie, vaskulare Chirurgie最新文献

Because of insufficient opening of Björk-Shiley- and Lillehei-Kaster-prostheses in vitro and in vivo a new pendulum valve is proposed. The skeleton line of the disc crossection is bent towards the main flow direction when the valve is closed. Thus during valve opening the blood stream is directed to the opposite of the opening direction as to add torque to the disc which enables complete valve opening. During flow observations in an open water table with eight different curved discs an increase of the opening angle with which the torque disappears could be measured with increasing curve of the disc. The pressure loss of the valve is smaller in comparison to the pressure loss of pendulum valves with plane or contrarily curved discs. Furthermore the curvature decreases the backflow volume during valve closure.

66 patients with 2 and 3 vessel coronary heart disease were studied before and after complete successful revascularization. Hemodynamic measurements and biplane left ventricular angiograms were obtained at rest and during supine bicycle exercise.--After operation a significant overall decrease of LVEDP with exercise was seen; exercise LVEF increased in cases with left main disease and in most cases with double vessel disease and double bypass. Inconsistant response was present in 3 vessel disease. Improvement of left ventricular dynamics with exercise in advanced coronary disease after complete revascularization can be expected mainly in 2 vessel disease and left main coronary disease.

The edge contrast pattern in Xeroradiography allows blood vessels to be delineated with highly reduced concentration of radiopaque fluid. The contrast material is injected rapidly into a cubital vein. The brachial arteries are opacified 3--8 sec. and the femoral arteries about 7--15 sec. after the injection is finished. The arteriograms are of good quality which equals direct conventional angiography, if the vessels are not overlayed by bone structures. Thus the popliteal artery can be judged best in lateral view. The indications for transvenous Xeroarteriography are preoperative diagnosis especially in high risk patients, angiographic diagnosis of soft tissue tumors and postoperative control and documentation of vascular reconstruction in the extremities. Transvenous Xeroarteriography is a really noninvasive, painless and easy to handle method whiich allows visualization of peripheral vascular lesions and can be reproduced at short intervals without any risk.

30 patients with chronic venous ulcerations of the lower leg, unable to be cured definitely by commonly known medical, local or surgical therapy are reported. All patients were submitted to the little known ulcer circumcision published by Nussbaum in 1873. During a postoperative period of up to 10 years there was no recurrence of ulcers in any case. The operation is simple and time saving. Requiring an average hospital stay of 24 days, thus saves expenses as well. The procedure is described and the clinical results obtained have been documented.

Two patients with infected aortic aneurysm underwent surgical treatment. When using autologous tissue in place of the infected aorta a recurrent aneurysm was observed four months later. Extraanatomical bypass of the infected area with prosthetic material and consecutive removal of all infected tissue seems to be the only successful management. This is confirmed by another patient who was treated successfully in this way. Prolonged antibiotic therapy after resection of infected aneurysms seems to be mandatory.

In a total of 21 mongrel dogs a comparison between intravital and postmortal coronary arteriograms was made so as to establish the difference in vessel diameter. Fresh postmortal hearts injected in situ showed an average increase in coronary vessel diameter of approx. 6 per cent. Examinations of 24 hour postmortal hearts which were removed from the animals showed a vessel diameter increase of barely 20 per cent in the mean. These 20 per cent correspond fairly well with literature information about the maximal widening of coronary vessels with nitroglycerin. Nerves which are still functioning, and humoral substances which may influence the still living muscle in vessel walls are supposed to be the reason for the smaller increase in fresh postmortal in situ illustrated coronary arteries. It must be stressed, that the measured differences between intravital and postmortal coronary artery diameters can only be representative of wall sections free of arterioslcerosis.

In 22 mongrel dogs the protective effect on the myocardium of Bretschneider- and Kirsch-Cardioplegia (90 minutes of cardiac arrest) was studied and compared with ischemic arrest (45 minutes at hypothermia of 30 degrees C). Myocardial contractility was evaluated by the following indices of contractility: t--dp/dt max., Krayenbühl-Index of contractility and max. Vce. Depression of contractility of 40 % was observed after ischemic arrest and Kirsch-Cardioplegia, whereas in Bretschneider-Cardioplegia depression was only 7 %. Forty-five minutes after reperfusion contractility had returned to normal in the last group. It is concluded that Bretschneider-Cardioplegia results in little reduction of postischemic contractility, and has a good protective effect on the myocardium.

In mongrel dogs myocardial stress of the following types of artificial cardiac arrest in moderate hypothermia and cardiopulmonary bypass was compared: 1. Ischemic arrest after aortic occlusion lasting 30 or 45 minutes. 2. Injection-cardioplegia according to Kirsch lasting 90 minutes. 3. infusion-cardioplegia according to Bretschneider lasting 90 minutes. The following parameters were compared: extracellular potassium activity ([K+]e) during cardiac arrest and [K+] in arterial and coronary venous blood during reflow, total [K+] and acid-base balance during reflow, time course of [K+] and lactic acid release and uptake during reflow after cardiac arrest. In our experimental conditions the lowest alterations of myocardial [K+] and acid-base balance were observed after infusion-cardioplegia according to Bretschneider. Injection-cardioplegia according to Kirsch was less protective for the heart as evidenced by more intensive acidosis, enlarged [K+] loss and prolongation of [K+] uptake during reflow. Ischemic cardiac arrest in moderate hypothermia was the worst type of artificial standstill indicated by development of fatal myocardial acidosis.

After induction of left ventricular hypertrophy by supravalvar constriction of the ascending aorta in mini pigs (ATP and lactate) were measured under different cardioplegic conditions. In normothermia and plain anoxic arrest ATP decrease and lactate increase were significantly slower in hypertrophied myocardium compared to normal myocardium. Injection cardioplegia using magnesium-aspartate-procaine at 37 degrees C did not influence the ATP decrease and lactate increase in the hypertrophied ventricle, whereas in the normal heart it showed some protection according to these parameters. Optimal ATP preservation and the lowest lactate increase rate were achieved in left ventricular hypertrophy by combined application of magnesium-aspartate-procaine and hypothermia of 25 degrees C. We conclude that normothermic injection cardioplegia has no protective effect on the hypertrophied left ventricle, whereas additional hypothermia can improve magnesium-aspartate-procaine cardioplegia significantly.

Dacron prostheses for replacement of the thoracic aorta were sealed with bioadhesive following the Viennese method. Native human fibrinogen was brought to coagulation by adding thrombin. Factor XIII was also added in order to accelerate polymerisation and to reinforce fibrin formation in the presence of thrombin and CaCl2, thus producing a stable thrombus. In order to avoid local fibrinolysis a fast but short-acting as well as a slow but longer-acting antifibrinolytic agent was added. This method was applied in twenty patients. The prostheses remained completely impermeable to blood after resuming circulation in spite of full heparinization. No post-operative haemorrhages from the prostheses were observed.