Effect of Enalapril Maleate on Cerebral Blood Flow in Patients with Chronic Heart Failure

The effect of enalapril on cerebral blood flow (CBF) was studied in 11 patients with chronic heart failure (NYHA II or III, dilated cardiomyopathy in 6 and old myocardial infarction in 5). CBF was evaluated by analyzing the Patlak-Plot curve obtained from radionuclide angiography with technetium-99m hexamethylpropylene amine oxime (99mTc-HM-PAO). Cardiac index (CI) and stroke volume (SV) were simultaneously measured by impedance cardiography. These measurements were performed before and at four weeks after daily administration of 5 mg enalapril. The stroke volume, cardiac index, and heart rate were not significantly changed after four weeks of enalapril admin istration. However, CBF was increased by 6.5% from 36.72 ±4.66 to 39.13 ±5.65 mL/ 100g/min (P<0.05). These results suggest that enalapril increased cerebral blood flow, which was not related to increased cardiac output in congestive heart failure. Patlak-Plot analysis of radionuclide angiography using 99m Tc-HM-PAO may be available for quantitative assessment of brain perfusion.