Chronic Intravascular Hemolysis after Aortic Valve Replacement

Abstract

To assess the severity of hemolysis and to determine whether severity of hemolysis was related to type of prosthesis, hematocrit readings (Hct), schistocyte counts (S), reticulocyte counts (R), and determinations of haptoglobin (Hp), lactic acid dehydrogenase (LDH), bilirubin, urinary hemoglobin, and urinary hemosiderin (Hs) were performed on 54 patients who had three different types of aortic ball-valve prostheses. Hemolysis, as determined by absence of haptoglobins or hemosiderinuria or R>3.5% in the absence of bleeding, was detected in 39 of the 54 patients (72%). S, R, LDH, and bilirubin were higher in patients without haptoglobins than in those with haptoglobins (P < 0.005). Hematocrits of less than 32% were found in 13 of the 34 patients (38%) with Starr-Edwards valves compared to none of the 11 with Magovern valves (P < 0.001) and one of the nine with Cutter (P < 0.05) valves. The combination of S>10 per 1,000 cells, R>5%, and LDH>500 mU was observed only with Starr-Edwards valves (16 of the 34 patients) and was not seen in patients with Magovern or Cutter valves (P < 0.005). All patients with S>10, R>5%, and LDH>500 mU had hemosiderinuria, and five had hemoglobinuria. Hemoglobinuria was always indicative of severe hemolysis. Hemosiderinuria was rarely detected less than 3 months after operation but was found in 32 of 47 patients so tested (68%) more than 3 months after operation. Hemosiderinuria was found in 25 of 30 patients with Starr-Edwards valves compared to two of the 11 with Magovern valves (P < 0.001). Hemosiderinuria was also detected in five of six patients with Cutter valves tested, but in three of these the test was only faintly positive. It is concluded that hemolysis is more severe in the presence of Starr-Edwards valves than Magovern or Cutter valves. Based on these observations, the following criteria for rapid clinical evaluation of cardiac hemolysis are suggested: Mild: Hs or absence of Hp but S5, LDH>500; severe: all of above plus hemoglobinuria.