Stent expansion of DES using current stent deliver systems is frequently suboptimal. Further more smaller minimal stent area (MSA) and stent underexpansion following deployment of DES are strong predictors of stent thrombosis and (TVR) target vessel revascularization. The investigators hypothesize than adjunctive postdilatation with noncompliant balloon can improve DES deployment.~After successful drug eluting stent implantation, patients will be randomized into two groups: Group A with no further dilatation, and Group B with additional post-dilatation with a noncompliant balloon. The investigators will performed IVUS analysis in groups A and B just before randomization and after post-dilatation in group B. Post dilatation will be performed with noncompliant balloon and with a nominal diameter 0.25mm larger than stent balloon.~The primary endpoint is optimum stent deployment. For defining the optimal stent deployment the investigators use the IVUS criteria adopted in the MUSIC study: Complete apposition without underexpansion and with symmetric stent expansion.~Patients are eligible after successful drug-eluting stent implantation in a native coronary artery. Patients with myocardial infarction or acute coronary syndrome will be excluded from the study.
Comparison with use of Intravascular Ultrasound (IVUS) analysis of two methods of percutaneous coronary interventions (PCI) with drug eluting stent:~After successful drug eluting stent implantation, patients were randomized into two groups: Group A had no further dilatation, and Group B had additional post-dilatation with a noncompliant balloon. The investigators performed IVUS analysis in groups A and B just before randomization and after post-dilatation in group B.