Long-term effect of simvastatin on the improvement of impaired myocardial flow reserve in patients with familial hypercholesterolemia without gender variance

BACKGROUND: Impaired myocardial flow reserve (MFR) in patients with familial hypercholesterolemia (FH) without evidence of ischemia has been reported. However, it has not been clarified whether diminished MFR in such male or female patients with FH can be reversed by simvastatin. METHODS AND RESULTS: Sixteen patients with FH and 16 age-matched control subjects were studied. All patients were proved to have no evidence of exercise stress-induced myocardial ischemia. Baseline myocardial blood flow (MBF) and MBF during dipyridamole administration (MBF [DP]) were measured with positron emission tomography and nitrogen 13 ammonia; MFR was then calculated before and 9 to 15 months after therapy with simvastatin (5-10 mg/day). Total cholesterol level was significantly higher in patients with FH (277 +/- 49.0) than in control subjects (190 +/- 14.9) but was normalized after lipid-lowering therapy (205 +/- 40.3). Baseline MBF was comparable among FH patients before (77.6 +/- 11.6 mL/min/100 g) and after therapy (74.5 +/- 9.62 mL/min/100 g) and control subjects (78.5 +/- 29.9 mL/min/100 g). However, MBF (DP) in FH patients before therapy (178 +/- 50.9 mL/min/100 g) was significantly lower than that in control subjects (282 +/- 148 mL/min/100 g) and was significantly improved after therapy (228 +/- 91.6 mL/min/100 g, P <.05). In fact, there was no statistically significant difference in the MBF (DP) value in FH patients after therapy compared with that in control subjects (P =.09). MFR significantly improved after therapy in patients with FH (3.33 +/- 1.19 vs 2.27 +/- 0.625, P <.01) and was then statistically comparable to that in control subjects (3.54 +/- 1.11). Improvement of MFR was observed whether MBF (DP) before therapy was greater than or less than 200 mL/min/100 g. MFR was improved in both male and female patients with FH. There was a significant relationship between percent change in plasma total cholesterol concentration and percent change in MFR before and after lipid-lowering therapy (r = -0.57, P <.05). CONCLUSIONS: Diminished MFR in patients with FH without evidence of ischemia can be reversed by moderate- to long-term simvastatin therapy without gender variance.