The effects of molsidomine (a direct nitric oxide donor) on the endothelial dysfunction have never been evaluated using reactive hyperemia peripheral arterial tonometry (RH-PAT). The objective of the MEDCOR double-blind trial will be to demonstrate the superiority of molsidomine (Coruno® 16 mg, once daily) over placebo, on improving the endothelial function (Endoscore by RH-PAT) after 12 months of treatment in stable angina patients undergoing elective percutaneous coronary intervention (PCI). Study design will take care of the real-life situation, in which patients are being offered PCI and stent placement (drug-eluting or bare metal), but also gold standard medical therapy (beta-blockers, statins, angiotensin-converting enzyme inhibitors (ACEIs), and/or calcium antagonists). Demonstrating clinical and statistical superiority of the study drug over placebo will be a real challenge. Therefore, a sequential approach has been designed with a pilot phase aiming at recruiting 50 patients. Upon evaluation of the results by an independent data steering committee, a larger sample size phase will eventually be considered.