Intravascular haemolysis and thrombocytopenia in left ventricular outflow obstruction.

Twenty-four patients with various types of isolated discrete aortic stenosis of a wide range of severity or with muscular obstruction to left ventricular outflow were studied haematologically and by cardiac catheterization and angiocardiography. Patients had haematocrits, reticulocyte, platelet, and megathrombocyte counts, serum haptoglobin, and lactic dehydrogenase performed; urine specimens were examined for haemosiderin and peri- pheral blood smears examinedfor schistocytes. Seventeen patients had 51chromium red blood cell survival tests and 7 patients had plasma heme pigment determinations.