Changes in Coronary Flow Reserve Assessed by Transthoracic Echocardiography after Lipid-Lowering Therapy in Patients with Hypercholesterolemia

Background：The coronary flow reserve is known to be reduced in patients with hypercholesterolemia, and has also been reported to improve after lipid-lowering therapy. Using transthoracic Doppler echocardiography, the changes in the coronary flow reserve were evaluated after lipid-lowering therapy in hypercholesterolemic patients. Methods：The coronary flow reserve was determined by pulsed-wave Doppler examination at the distal left anterior descending coronary artery before and after five months of lipid-lowering therapy in 14 hypercholesterolemic patients (total cholesterol ≥230 mg/dL) with no other modifiable risk factors of coronary heart disease. Results：In all patients, the total cholesterol and low-density lipoprotein (LDL) cholesterol were significantly decreased after therapy (from 273±27 mg/dL to 199±22 mg/dL, p=0.001, from 182±25 mg/dL to 110±27 mg/dL, p=0.001, respectively). However, there was no significant change in the coronary flow reserve after lipid-lowering therapy (from 2.4±0.5 to 2.5±0.5, p=0.875). The Baseline LDL-cholesterol showed an inverse correlation with the baseline coronary flow reserve (r =-0.649, p=0.012). Conclusions：In the present study, no significant change in the coronary flow reserve was noted after lipid-lowering therapy in hypercholesterolemic patients with no other risk factors of coronary heart disease, although the baseline LDL-cholesterol levels were found to correlate well with the baseline coronary flow reserve. Transthoracic Doppler echocardiography can be used to easily and non-invasively evaluate the changes in the coronary flow velocity, coronary flow reserve and other related parameters. Therefore, a controlled trial using transthoracic Doppler echocardiography relating to the effect of lipid-lowering therapy on patients showing a wider range of baseline risk factors and LDL