Aims: The pathophysiological mechanism in cardiac syndrome-X (anginal chest pain, positive exercise test, and angiographically normal coronary arteries) has been suggested as an impairment in normal endothelial function of the coronary microvasculature, resulting in inadequate flow reserve. The aim of this study was to determine whether statins with proven beneficial effects on endothelium, have any effect on endothelial functions and exercise induced ischaemia in cardiac syndrome-X.
Methods and results: Study population consisted of prospectively enrolled 40 patients with cardiac syndrome-X. Patients with left ventricular hypertrophy, hypertension, diabetes mellitus, and LDL levels >/=160 mg/dl were excluded. Half of the patients received pravastatin (40 mg/day) for 3 months irrespective of their lipid values, according to a single-blind, randomized, placebo-controlled design. Endothelial functions were assessed with high-resolution vascular ultrasound, which measured the brachial artery flow mediated dilatation (FMD). Lipid measurements, symptom limited exercise tests and vascular ultrasound images were obtained before and at the end of 3 months. After the treatment, FMD improved significantly in pravastatin group. Exercise duration, and time to 1mm-ST depression were significantly prolonged after statin therapy. Ischaemic symptoms and ECG findings during exercise test disappeared completely in 5 (26%) patients in the statin group. However, there were no significant changes in FMD and exercise parameters in placebo group.
Conclusions: Statin therapy resulted in beneficial effects on both exercise induced ischaemia and FMD in cardiac syndrome-X. The mechanism of this beneficial effect is probably the result of improvement in endothelial functions.