R Hetzer - Böcker

It was the genius of Gordon Murray in Toronto that introduced the use of allografts into cardiac surgery in the 1950s. Soon after this on opposite sides ofthe world, Sir Brian Barratt-Boyes in Auckland, New Zealand, and Mr. Donald Ross in London, undertook to use allografts for the replacement of diseased aortic valves. Since that time the global interest in allografts has been patchy, episodic, and without a con­ sensus. Nonetheless, for the last 20 years at least three groups in the world have steadfastly pursued the development of new and relevant information concerning the use of allograft valves in humans. These are the centres of Sir Brian Barratt­ Boyes, Mr. Donald Ross, and Mark O'Brien in Brisbane. More recently, talented investigators, including Drs. Yankah, Yacoub, and others, have been developing information concerning the immunological aspects of the use of allografts, as well as their clinical use. No doubt, at present, cardiac valve allografts of one sort or another are the devices of choice for conduits and have an important place in the surgery of aortic valve replacement. Even so, in the mind of this writer at least, the future usefulness of allografts for the replacement of diseased cardiac valves and conduits between a ventricle and the pulmonary artery, remains problematic, and depends upon improvements in other devices for this purpose and upon improve­ ments that may be made in preparing and using allografts.

After decades of laboratory investigations mechanical circulatory support for the failing heart has entered the clinical arena. Today, a growing number of patients with progressive myocardial failure awaiting cardiac transplantation is successfully bridged to transplantation with ventricular assist devices. The proceedings of the "Mechanical Circulatory Support"-meeting, held in Berlin, October 21-22, 1995, present new aspects of mechanical circulatory support, recent experience with MCS in newborns and children using specially developed small devices, and the results of long-term mechanical assistance. The ability of the myocardium to recover under pressure de-loading and reduced workload is discussed. All these topics open up new perspectives for the use of mechanical circulatory support, not only as a bridge to transplantation, but also as a definitive approach for treating patients with end-stage heart failure. Some of these concepts may even provide real alternatives to heart transplantation, these being sorely needed in light of the severe donor organ shortage. Regulatory as well as ethical aspects of the extended use of mechanical circulatory support systems and new technical developments in the field are discussed by internationally distinguished experts.

Clinical lung transplantation has seen an early start within the history of solid organ trans­ plantation, marked by the 1963 first lung transplant by James D. Hardy. This was prompted by the seemingly easy way of joining the transplanted organ to the recipient by me ans of a few well-defined anastomoses, i.e. bronchus, pulmonary artery and pulmonary vein carry­ ing left atrial cuff. The following decade thus witnessed a number of such mostly unilateral lung transplants in several centres, in Germany represented by the two only lung transplants performed by E. S. Bücherl, then at the Neukölln City Hospital in Berlin in 1969. As with most other such attempts these two patients suffered early and lethai graft failure. There was only one single lung transplant patient who lived up to ten months after the transplant at Gent, Belgium, having been operated on by Derom in 1969. The alm ost universal failure during this initial phase was attributed to bronchial anasto­ motic insufficiency, pulmonary infection of either the transplanted lung or the left-in-place contralateral lung and a far-reaching lack of knowledge how to cope with transplant rejec­ tion. In the early 1970s it had become gene rally accepted that lung transplantation could not be performed successfully.

Cardiac surgery has developed dramatically since the first open-he art operations were performed in the mid 1950s. Although the improvement of surgical technique, extracorporeal circulation, and postoperative management has contributed to a marked reduction of morbidity and mortality, the development of cardiac surgery to its present state would not have been possible without blood substitution by homologous donor blood. Only 20 years ago, open-heart operations required an average of 8 units of blood preserves. The excessive need of donor blood in those early days was mainly due to premature surgical technique, insecure control of anticoagulation, severe blood trauma by extracorporeal circulation, and the lack of retransfusion technologies that would have allowed the reuse of shed mediastinal blood. The introduction of new technologies, such as normovolemic hemodilution, in­ traoperative autotransfusion, postoperative return of shed mediastinal blood, and predonation of autologous blood has greatly reduced donor blood requirements. At present the majority of routine coronary artery surgical procedures can be performed without any blood transfusion. Blood loss, however, may be considerable in patients undergoing complex valve surgery or reoperations, as they often require several units of transfused blood. Blood conservation has now become an area of major interest for the cardiac surgeon. This increased concern is caused by infectious complications of blood transfusion, in particular hepatitis and, more recently, AIDS.

The International Symposium on Ischemic Mitral Incompetence was held December2-4,1988 at the Intercontinental Hotel, Berlin . It wasorganized bythe German Heart Center Berlin with the primary aim to bring together experts interested in the subject of ischemic mitral regurgitation. Our intention was to face the problems associated with diagnosis and treatment of mitral incompetence resulting from coronary artery disease. A "work-up" of the whole topic from its basic, diagnostic, and surgical aspects wasinitiated. In the first section weconcentrate on the basic anatomical and pathophysiological knowledge, as well as on experimental work. In the second section cardiologists report on inci- dence of ischemic mitral incompetence, diagnostic methods that include esophageal echocardiography, follow-up studies of medical- and surgical-treated patients. This section considers interventional therapy in acute myocardial infarc- tion, as well.The third section includes contributions by cardiac surgeons with many years' experience in operative treatment of ischemic mitral incompetence including the decision-making criteria for non-mitral valve surgery, and for valve reconstruction or replacement.