Urinary Iron Excretion in Valvular Heart Disease and After Heart Valve Replacement

Urinary iron excretion and other aspects of iron metabolism were studied in patients with valvular heart disease before and after valve replacement with heterografts or Starr-Edwards prostheses. Eighty-one per cent of preoperative patients had increased daily urinary iron excretion (0.14-2.2 mg./24 hours) and 61 per cent had a reduced ⁵¹Cr survival time. Serum iron levels were low in two patients but iron-deficiency anemia was not observed. Fifty-three per cent of bone marrow aspirates had reduced or absent storage iron. Patients with normally functioning heterografts had no hemolysis and urinary iron excretion decreased exponentially with time until normal values were reached in 6-10 months after surgery. Calculated iron loss over a 6-month postoperative period varied from 11 to 360 mg. Serum iron levels and results of ferrokinetic studies returned towards normal, as did marrow iron stores. Seven patients (78%) with Starr-Edwards valves had evidence of hemolysis by the ⁵¹chromium survival method and six were anemic. Urinary iron loss was abnormal in all nine patients (0.8-10.8 mg./24 hours) and iron deficiency was a significant factor in the anemia noted. Iron therapy raised hemoglobin values in the two patients to whom it was administered. Urinary iron excretion was found to be a sensitive index of intravascular hemolysis, particularly in the presence of an intermittent hemolytic process.