Mechanical trauma to red blood cells caused by Björk-Shiley and Carpentier-Edwards heart valves.

The haemolytic properties of mechanical and biologic valve prostheses are well established, and it is known that they can shorten red cell survival time (1, 2). Their effects on red cell deformability are not known, however. A comparative study was therefore made of two valve types--Björk-Shiley (BS) and Carpentier-Edwards (CE). Thirty-nine patients with normally functioning valve prostheses (23 BS, 16 CE) were studied at least one year after surgery, by assessing red cell deformability measured as red cell filtration rate (RFR), red cell survival half-time with the Cr-51 isotope method (Cr-51 T1/2) and plasma-haemoglobin (P-Hb). The BS valve was shown to be more traumatic to the cells than the CE valve and effected greater reduction of the deformability of these cells. Significant intercorrelations were found between RFR, CR-51 T1/2 and P-Hb.