1. Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg , Gothenburg, Sweden
2. Department of Cardiothoracic Surgery, Region Västra Götaland, Sahlgrenska University Hospital , Gothenburg, Sweden
3. Department of Cardiology, Region Västra Götaland, Sahlgrenska University Hospital , Gothenburg, Sweden
4. Department of Cardiothoracic Surgery, Landspitali University Hospital , Reykjavik, Iceland
5. Faculty of Medicine, University of Iceland , Reykjavik, Iceland
6. Centre for Registries, Region Västra Götaland , Gothenburg, Sweden