Background Atherosclerosis is a chronic, systemic and diffusely distributed disease causing focal complications in different vascular beds.~Impaired endothelial function is the initial step in the progressive course of atherosclerosis . Endothelial dysfunction is considered a systemic process and both coronary and peripheral endothelial dysfunction have been shown to be independently associated with cardiovascular events .~Percutanenous coronary intervention (PCI) with implantation of stent is the treatment of choice in symptomatic stenotic coronary artyery disease (CAD), but in-stent restenosis and progression of disease remains its main limitation. Early identification of patients at risk of restenosis after PCI would therefore be of clinical value. There is only limited prospective data on the role of peripheral endothelial dysfunction after PCI predicting restenosis and cardiovascular events , , .~Furthermore, it is unknown if peripheral endothelial dysfunction is associated with increased levels of biomarkers of endothelial cell activation in this population.~There are conflicting data on inflammatory markers as high-sensitivity CRP with regard to endothelial function.~Low heart rate variability (HRV) predicts automic dysfunction and is a strong and independent predictor of mortality in patients with coronary artery disease (CAD) . Clinical depression after myocardial infarction is associated with decreased HRV, linking depression to increased cardiac mortality in post-myocardial infarction patients . Whether decreased HRV is associated with endothelial dysfunction or restenosis is unknown.~Objective The objective of this study is to evaluate whether impaired endothelial function and low HRV are associated with clinical restenosis.~Furthermore, the study examines a potential correlation between biomarkers of endothelial cell activation and endothelial dysfunction.~Another issue is depression after PCI and a potential association with impaired endothelial function and increased levels of makers for endothelial activation.~Methods~Subjects This prospective study includes consecutively patients with acute coronary syndromes undergoing PCI with stent implantation for significant single vessel disease at Stavanger University Hospital, Stavanger, Norway. Patients will be followed for at least 6 months.~Exclusion criteria are multivessel disease, left ventricular dysfunction defined as ejection fraction (EF) < 50%, former aortocoronary bypass-surgery, systemic inflammatory diseases other than atherosclerosis, cognitive impairement, severe psychiatric disorder, renal failure (kreatinin > 250 mmol/l), refusion to participate.
The objective of this study is to evaluate whether impaired endothelial function and low heart rate variability are associated with clinical restenosis after percutaneous coronary intervention with stent implantation in patients with angina or acute coronary syndrome.~Furthermore, the study examines a potential correlation between biomarkers of endothelial cell activation and endothelial dysfunction.