[1] Orebro Univ Hosp, Dept Cardiol, SE-70185 Orebro, Sweden
[2] Orebro Univ Hosp, Dept Cardiothorac Surg, SE-70185 Orebro, Sweden
[3] Orebro Univ Hosp, Dept Biostat, SE-70185 Orebro, Sweden
[4] Orebro Univ Hosp, Dept Transfus Med, SE-70185 Orebro, Sweden
[5] Cent Hosp Karlstad, Dept Clin Physiol, Karlstad, Sweden