[1] Univ Oslo, Rikshosp, Oslo Univ Hosp, Dept Cardiol, N-0027 Oslo, Norway
[2] Univ Oslo, Rikshosp, Oslo Univ Hosp, Internal Med Res Inst, N-0027 Oslo, Norway
[3] Univ Oslo, Rikshosp, Oslo Univ Hosp, Dept Radiol, N-0027 Oslo, Norway
[4] Sahlgrens Univ Hosp, Gothenburg, Sweden
[5] Univ Oslo, Rikshosp, Oslo Univ Hosp, Dept Thorac & Cardiovasc Surg,Sect Clin Immunol &, N-0027 Oslo, Norway