Endothelial function is evaluated at baseline, at 6 and 12 month non-invasively. A high resolution ultrasound scan is performed on the right brachial artery to assess post ischemic flow mediated changes in arterial diameter. Flow mediated dilatation (FMD) depends on an intact endothelium and is mediated via endogenous nitric oxid (NO). To test non-endothelium dependent vasodilatation 0.4 mg of sublingual nitroglycerin (NG) is administrated. NG is a smooth muscle relaxant and acts as a source of NO.There is a well described relation tween endothelial function in the coronary arteries and in the brachial artery.