University of Gothenburg - Department of Cardiothoracic Surgery, University of Copenhagen - Department of Cardiology, University of Helsinki - Department of of Cardiac Surgery, University of Oslo - Department of Respiratory Medicine, Lund University - Department of Pulmonology and Allergology, University Hospital of Copenhagen - Department of Thoracic Surgery, University of Helsinki - Department of Pulmonology, University of Oslo - Department of Cardiothoracic Surgery, Lund University - Department of Cardiothoracic Surgery, University of Gothenburg - Pulmonary Department and University of Gothenburg - Pulmonary Department