1. Department of Thoracic and Cardiovascular Surgery, Larissa University Hospital, P.O. Box 1425, 41110 Larissa, Greece
2. Department of Thoracic and Cardiovacsular Surgery, School of Medicine, University of Thessaly, Biopolis, P.O. Box 1400, 411 10 Larissa, Greece
3. Department of Cardiology, Larissa University Hospital, P.O. Box 1425, 411 10 Larissa, Greece
4. Department of Vascular Surgery, Larissa University Hospital, P.O. Box 1425, 411 10 Larissa, Greece
5. Cardiology Division, Emory University, Atlanta, GA 30322, USA