Erythrocyte Destruction in Different Types

Increased destruction of red blood cells follows the insertion of ball valves into the heart in most cases. Usually, hemolysis is slight, but in some patients uncompensated hemolytic anemia develops. To study the influence on hemolysis of the mechanical pro-perties of the prostheses, the degree of erythrocyte destruction was evaluated in patients with Starr-Edwards aortic prostheses of different types and size. Fifty-six patients with Starr-Edwards aortic ball valves were examined; 13 had prostheses of the 1200 series with silastic rubber balls, and 43 had valves of the 2300 series with hollow Stellite (metallic) balls. Thirty-one patients had valves with an orifice area of 1.8 cm2 or less; the others had larger-sized valves. The degree of hemolysis was predicted from the serum lactic dehydrogenase activity, which has previously been shown to correlate well with the red blood cell survival. The half-life of 5'Cr-labelled red cells was also determined in 16 cases. Hemolysis was significantly higher in patients with Stellite ball valves than in those with silastic rubber ball valves, and red blood cell destruction was more pronounced in patients with small prostheses than in patients with larger valves. Hemolysis was not higher in three patients with paravalvular leakage than in patients with competent prostheses. Valve type and size seem to be the most important factors in producing hemolysis. Additional Indexing Words: Intravascular hemolysis Serum lactic dehydrogenase INCREASED destruction of red blood cells is the most common side effect following insertion of ball valve prostheses. Usually, it is slight and compensated by increased erythro-cyte production, but in a few patients severe hemolytic anemia develops. ' Paravalvular leakage2 ' 3and ball variance4-6 might explain the hemolysis in some cases, but in others no faults of the prosthesis or its insertion could be demonstrated.7 ' 8 Valve prostheses of different construction may have different traumatic effects in the red blood cells.9 This study shows that the hemolytic effect may be changed considerabl