Reduced membrane sialic acid contents of the erythrocytes after heart valve replacement with prosthetic devices.

Mild traumatic hemolysis due to heart valve prosthesis was investigated in three groups of patients with different prosthesis device (tilting disc, ball valve) inserted in aortic area, or in mitral area. By routine laboratory tests, an increased but not remarkable erythrocyte destruction was evidenced. On the other hand, the content of membrane sialic acid of the erythrocytes was determined in patient and control groups in order to give evidence of membrane damage induced by the prosthetic device. The mean value of sialic acid in the patient groups was significantly lower than in controls. These findings may suggest that mechanical damage on the red blood cell (RBC) membrane could be associated with the decrease of the membrane sialic acid content. It is briefly discussed whether the observed low contents of RBC sialic acid may somehow explain the decreased RBC lifespan which is frequently reported in these patients.