III RESULTS OF TESTS FOR HAEMOLYSIS AND FOR OSMOTIC FRAGILITY OF RED BLOOD CELLS Osmotic Fragility

SYNOPSIS Nineteen patients with morphological abnormalities of the red blood cells are described, and these formed approximately 3 % of the total cases of cardiac valvular disease. In two patients the abnormal blood film developed after the insertion of an aortic and mitral valve prosthesis respectively, but in another two patients the abnormal blood film was corrected by aortic valve surgery. Anisopoikilocytosis may have been associated with microangiopathic haemolytic anaemia in one patient, but in the others the cardiac valvular disease was severe and other mechanical factors were not present. The mitral valve was involved in 16 patients and the aortic valve in eight. Elliptocytosis was the only abnormality in 11 blood films, schistocytes and burr cells were present in seven, and in three there were a few microspherocytes. Family studies in seven patients produced evidence of hereditary elliptocytosis in three. Anaemia was present in only two patients. One of these had infective endocarditis, and the other developed overt haemolytic anaemia following the replacement of a diseased mitral valve by a Starr-Edwards prosthesis. In this latter case there was a transiently positive direct antiglobulin test, and the anaemia and abnormal blood picture were corrected without further surgical treatment. Haemolytic anaemia did not develop in 23 patients after the insertion of an aortic valve prosthesis