1. Department of Vascular Surgery, Heart Centre; Kuopio University Hospital; FI-70029 Kuopio Finland
2. Department of Orthopaedics and Traumatology; Päijät-Häme Central Hospital; FI-15850 Lahti Finland
3. Vääksy Medical Centre; FI-17200 Vääksy Finland
4. Department of Cardiac Surgery, Heart and Lung Centre; Helsinki University Hospital; FI-00029 Helsinki Finland