[1] UNIV LUND HOSP,DEPT PEDIAT,S-22185 LUND,SWEDEN
[2] UNIV UPPSALA HOSP,DEPT THORAC SURG,S-75014 UPPSALA,SWEDEN
[3] UNIV LUND HOSP,DEPT PEDIAT,S-22185 LUND,SWEDEN
[4] UNIV UPPSALA HOSP,DEPT THORAC SURG,S-75014 UPPSALA,SWEDEN
[5] UMEA UNIV,DEPT PEDIAT,S-90185 UMEA,SWEDEN