Improvement of impaired myocardial vasodilatation due to diffuse coronary atherosclerosis in hypercholesterolemics after lipid-lowering therapy

Background-Diminished myocardial vasodilatation (MVD) in hypercholesterolem ics without overt coronary stenosis has been reported. However, whether the diminished MVD of angiographically normal coronary arteries in hypercholes terolemics can be reversed after lipid-lowering therapy is not known, Methods and Results-A total of 27 hypercholesterolemics and 16 age-matched controls were studied. All patients had >1 normal coronary artery, and thos e segments that were perfused by anatomically normal coronary arteries were studied, Myocardial blood flow (MBF) was measured during dipyridamole load ing and at baseline using positron emission tomography and N-13-ammonia, af ter which MVD was calculated before and after lipid-lowering therapy. Total cholesterol was significantly higher in hypercholesterolemics (263+/-33.8) than in controls (195+/-16.6), and it normalized after lipid-lowering ther apy (197+/-19.9). Baseline MBF (ml.min(-1).100 g(-1)) was comparable among hypercholesterolemics (both before and after therapy) and controls. MBF dur ing dipyridamole loading was significantly lower in hypercholesterolemics b efore therapy (189+/-75.4) than in controls (299+/-162, P<0.01), However, M BF during dipyridamole loading significantly increased after therapy (226+/ -84.7; P<0.01). MVD significantly improved after therapy in hypercholestero lemics (2.77+/-1.35 after treatment [P<0.05] versus 2.02+/-0.68 before trea tment [P<0.01]), but it remained significantly higher in controls (3.69+/-1 .13, P<0.01). There was a significant relationship between the percent chan ge of total cholesterol and the percent change of MVD before and after lipi d-lowering therapy (r=-0.61, P<0.05). Conclusions-Diminished MVD of anatomically normal coronary arteries in hype rcholesterolemics can be reversed after lipid-lowering therapy.