[Mechanism and prevention of postoperative hemolysis in the corrective surgery of subarterial ventricular septal defects].

Intravascular hemolysis following the repair of subarterial ventricular septal defects (VSD) was studied in 34 patients. The VSD was closed through a main pulmonary arteriotomy with a Dacron double-velour patch (Meadox, Oakland, NJ) in 17 cases (Group B) and with a Dacron single-velour patch covered by autologous pericardium facing toward the right ventricular outflow tract (RVOT) in 17 cases (Group A). No significant intergroup difference in age, weight, Qp/Qs, Pp/Ps, and Rp/Rs was found. There were no significant differences in the preoperative values of serum LDH, total bilirubin, and flow velocity at the RVOT (Group A: 1.7 +/- 0.4 m/sec vs Group B 1.8 +/- 1.0 m/sec). The severity of hemolysis was evaluated by serum LDH levels, total bilirubin levels, and hemoglobinuria on the morning of the first operative day. Postoperative LDH levels were significantly lower in the Group A (812 +/- 205 IU/L) than in the Group B (1098 +/- 427 IU/L) (p < 0.05). Hemoglobinuria developed in 2 patients in Group B (12%) and none in Group A. These data suggest that the pericardium apparently protects against postoperative hemolysis. The intensity of the turbulence at the RVOT was graded as follows using color-doppler echocardiography (0: none; Grade 1: turbulence was detected near the patch only; Grade 2: turbulence was detected halfway to the RVOT; Grade 3: turbulence extended to the anterior wall of the RVOT). The relationship between the presence of hemolysis and the degree of turbulence was examined. Turbulence at the RVOT appeared in 73% of those in Group A and in 82% of those in Group B.(ABSTRACT TRUNCATED AT 250 WORDS)