Fragmentation hemolysis in idiopathic hypertrophic subaortic stenosis.

A 69-year-old woman with previously asymptomatic IHSS developed fragmentation hemolytic anemia in association with bacterial endocarditis when the calculated pressure gradient across the left ventricular outflow tract was 82 mm Hg. Partial correction of the anemia by transfusion resulted in a prompt reduction in fragmentation. The interplay of anemia and increased pressure gradient in the production of red cell fragmentation is discussed.