Evaluation of intravascular hemolysis by haptoglobin administration after prosthetic valve replacement

Although the measurement of serum haptoglobin (S-Hp) is of great use for evaluation of intravascular hemolysis, it is not applicable in patients with mechanical prosthetic valves because S-Hp is virtually absent. We administered haptoglobin preparation to 10 patients with Björk-Shiley mitral prosthetic valves and 10 patients with the same aortic prosthetic valves. Serum haptoglobin levels were measured periodically afterwards. The maximum haptoglobin levels (Hp (max)), serum, haptoglobin reducing rate ((Hp-delta Hp)/delta t) and expected haptoglobin disappearing time (hours) were obtained from the subsequent samples. The screening studies which were performed at the same time were not predictors of difference in the 2 groups. On the other hand, serum haptoglobin reducing rate and expected haptoglobin disappearing time indicated that hemolysis is higher in patients with an aortic prosthetic valve than with a mitral prosthetic valve. This haptoglobin administration test seems to be useful for the comparative examination of the intravascular hemolysis caused by the difference in the position of the prosthetic valve.