With increasing age, arterial endothelial cell function is impaired, which is associated with decreased regeneration response and increased intimal hyperplasia after endothelial injury. Dietary flavanols can reduce endothelial dysfunction acutely and chronically, but the exact mechanism is unknown. Recent studies suggest that flavanols may affect important endothelial regeneration response processes and possibly mediate long-term positive vascular effects. The aim of this study is to investigate age-dependent mechanisms of impaired endothelial regeneration and the influence of dietary flavanols on them. For this purpose, younger and old male patients, who are clinically indicated for elective transradial catheterization, will get periinterventional a test drink , which is rich on flavonols (800 mg flavanols daily), or control drink. Administration of drinks is randomized and double-blind. The test drinks should be given one week before the elective catheter examination until 1 week later. The endothelial regeneration is to be investigated as endothelium-dependent vasodilation non-invasively in the area of the puncture site on the forearm and by means of biomarkers in the blood. The endothelial function of the Arteria radialis will be measured with Flow Mediated Dilation (FMD) before and 24 h after catheterization. One month after catheterization patients undergo ultrasound examination of arteria radialis, to include structural vessel wall changes as intimal media thickness.

Inclusion Criteria:

• planed catheterization, that has be done via Arteria radialis

Exclusion Criteria:

• acute infection (CRP>0.5 mg/dl)
• malignant diseases
• heart failure (NYHA III-IV)
• renal failure (GFR<60 ml/min)
• profoundly atrial fibrilation
• hypotension (≤100/60 mmHg)
• intolerance of nitroglycerin