Chronic heart failure induced by multiple sequential coronary microembolization in sheep.

OBJECTIVE: Although a large variety of animal models for acute ischemia and acute heart failure exist, valuable models for studies on the effect of ventricular assist devices in chronic heart failure are scarce. We aimed to establish a stable and reproducible animal model of chronic heart failure in sheep. METHODS: Sheep (n=8, 77 +/- 4 kg) were anesthesized and a 5F sheath was implanted into the left carotid artery. The left main coronary artery was catheterized under flouroscopic guidance and bolus injection of polysterol microspheres (90 microm, n=25.000) was performed. Microembolization (ME) was repeated up to three times in two to three week intervals until animals started to develop stable clinical signs of heart failure. Clinical and echocardiographic data were analyzed at baseline (base) and at three months (3 mo) after first ME. All animals were followed for 3 months after first microembolization and then sacrificed for histological examination. Another four healthy sheep (79+/-6 kg) served as control animals. RESULTS: All animals developed clinical signs of heart failure as indicated by increased heart rate at rest (68+/-4 bpm (base) to 93 +/- 5 bpm (3 mo) (p<0.05)), increased respiratory rate at rest (28+/-5 (base) to 38 +/- 7 (3 mo) (p<0.05)) and increased body weight 77 +/- 2 kg to 81 +/- 2 kg (p<0.05) due to pleural effusion, peripheral edema and ascites. Echocardiographic evaluation revealed significantly an increase of left ventricular enddiastolic diameter from 46 +/- 3 mm (base) to 61 +/- 4 mm (3 mo) (p<0.05). Clinically and echocardiographically no significant changes were revealed in healthy control animals. CONCLUSIONS: We conclude that multiple sequential intracoronary microembolization can effectively induce myocardial dysfunction with clinical and echocardiographical signs of chronic ischemic cardiomyopathy. The present model may be suitable in experimental work on heart failure and left ventricular assist devices, e.g. for studying the impact of mechanical unloading, mechanisms of recovery and reverse remodeling.

[Josef Koncz (1916-1988)--pioneer of cardiac surgery]. / Josef Koncz (1916-1988)--Pionier der Herzchirurgie.

Josef Koncz (1916-1988) was until given emeritus status in 1982 director of the Department of Cardiothoracic and Vascular Surgery, which was specifically founded for him in Goettingen, Germany. By the fusion of three different surgical branches the University hospital of Goettingen took over the role of a pacemaker and initiated a standard in the development of this new specialty in Germany. The scientific and clinical work done by the Department of Cardiothoracic and Vascular Surgery was shaped by the personality of the surgeon and scientist Josef Koncz. He was a successful surgeon and innovative pioneer in one person. Already in 1956, he started open-heart surgery and proceeded this technique in an impressing series. In 1965 he was the first in Germany who operated upon the transposition of the great vessels by Mustard's method and developed together with his long-standing assistant, Huschang Rastan, an operation technique to extend the left-ventricular outflow tract combined with tunnel-shaped subvalvular aortic valve stenosis. Another essential element of his work is related to the establishment of the Cardiothoracic and Vascular Surgery as an independent specialty, ending in the foundation of the German Society for Thoracic and Cardiovascular Surgery in 1971.

In vitro thrombogenicity testing of artificial organs.

Thromboembolic complications remain as one of the main problems for blood contacting artificial organs such as heart valves, bloodpumps and others. In vitro evaluation of thrombogenesis in prototypes has not previously been part of the standard evaluation of these devices. In comparison to hemolysis testing, evaluation of the thrombogenic potential is more difficult to perform because of the complexity of the blood coagulation system. We present an in vitro testing procedure that allows the accelerated examination of the thrombogenic potential of different types of blood pumps. Additionally, first results are presented that indicate the reliability of the accelerated clotting test for mechanical heart valves. Results for the centrifugal pump BioMedicus and two microaxial pumps have shown typical thrombus formation at locations such as bearings. The results indicate that the accelerated clotting test is an excellent addition to the much more expensive animal testing of artificial organs or assist devices. In vitro testing permits studies of thrombus formation to be performed at an early stage and at low costs and also facilitates a more precise investigation of device areas known to be potential hot spots for thrombus formation.