Late chronic hemolysis after valve replacement for aortic stenosis. Relation to residual hypertrophy and impaired left ventricular function. The relationship between intravascular hemolysis induced by aortic valve prosteses and patient status/left ventricular (LV) function (radionuclide cardiography) was examined in 63 patients of 65 who were alive ten to seventeen years after valve replacement (1965-1973) for aortic stenosis. Serum-lactic dehydrogenase (LDH) exceeded upper reference limit in 62 patients and S-haptoglobin (HAPTO) was reduced in 62. One patient with normal LDH had reduced HAPTO and elevated plasma-hemoglobin. Anemia was noted in 4 patients (6%). S-LDH was higher in men than in women (p less than 0.05), in patients with increased ECG hypertrophy score than in those with a normal score (p less than 0.05), in patients with NYHA class II-III than in those with class I (p less than 0.05), in patients with abnormal LV function than in those with a normal radionuclide study (p less than 0.05), in patients with a pathologic Q wave in the ECG than in those without (p less than 0.05), and in patients with a Starr Edwards cloth-covered (SECC) prosthesis than in those with other types (p = 0.07). ECG hypertrophy score correlated directly with LDH (r = 0.33, p = 0.008) and inversely with LV ejection fraction (r = -0.57, p less than 0.0001), peak ejection rate (r = -0.47, p less than 0.0001), and peak filling rate (r = -0.41, p less than 0.001). Multiple linear regression analysis revealed that LDH was accounted for by ECG hypertrophy score (p = 0.001), SECC prosthesis (p = 0.04), and male gender (p = 0.05). Hypertrophic malfunctioning left ventricles may be responsible for higher degrees of turbulent flow characteristics in the vicinity of prosthetic valves in the aortic position and, by inference, explain the increased tendency toward hemolysis in these patients. 