University Hospital of Aachen, Germany (1989-98)
Harvard Medical School, Boston, Mass. USA (1998-99)
Ludwig-Maximilians-University Grosshadern, Munich, Germany (1998-2007)
Wilhelms-University, Muenster, Germany (2007-2008)
Head of Heart Center Duisburg, Germany (since 2008
Development of polyurethane heart valves
Minimally invasive cardiac surgery
Mitral valve surgery
Tissue engineering
Cardiovascular intensive care
Entire field of adult cardiac surgery
Early corrective pediatric cardiac surgery
Pediatric and adult cardiac transplantation