Test of Long-Term Safety and Efficacy of Sirolimus-Permanent-Polymer Eluting Stent (Cypher)- and Sirolimus-Polymer-free Eluting Stents (PPS/PFS) Assessed by Optical Coherence Tomography (PPS/PFS-OCT)

• Percentage of malapposed strut assessed by OCT [ Time Frame: 5 years ]
• Percentage of uncovered malapposed struts assessed by OCT [ Time Frame: 5 years ]
• Morphologic differences of neointima between stents [ Time Frame: 5 years ]
• Late lumen loss at 5 years assessed by OCT [ Time Frame: 5 years ]

The mid-term efficacy of drug-eluting stents has been well-established, but there is an ongoing debate on the potential of an increased incidence of late stent thrombosis, particularly after discontinuation of thienopyridine therapy, as well as of delayed onset of restenosis or catch-up phenomenon with permanent polymer-based DES. The extent of strut coverage with reduction of exposed thrombogenic material has been shown to be associated with the inflammatory reaction grade and with the incidence of stent thrombosis. The optical coherence tomography (OCT) is an intravascular imaging modality based on light. The principle is similar to intravascular ultrasound, but due to the much shorter wave length of light, it offers a much better resolution up to 10µm, enabling the exact determination of strut coverage, neointimal thickness, vessel size, presence of dissections, and even the presence of inflammation.

Patients who received a polymer-free or a permanent-polymer sirolimus-eluting stent about 5 years ago without in-segment intervention since, will be evaluated by OCT regarding the healing pattern and the late lumen loss of the stent.

• Device: Sirolimus-Permanent-Polymer Eluting Stent
  due randomization sirolimus-permanent-polymer eluting stent was implanted
  Other Name: Cypher®
• Device: Sirolimus-Polymer-free Eluting Stent
  due randomization sirolimus-polymer-free eluting stent was implanted
  Other Name: ISAR Rapa G1

• Active Comparator: Arm 1
  Sirolimus-Permanent-Polymer Eluting Stent
  Intervention: Device: Sirolimus-Permanent-Polymer Eluting Stent
• Active Comparator: Arm 2
  Sirolimus-Polymer-free Eluting Stent
  Intervention: Device: Sirolimus-Polymer-free Eluting Stent

Inclusion Criteria:

• Patients older than age 18 with with previous implantation of polymer-free or permanent-polymer sirolimus-eluting stents 5 years ago due to ischemic symptoms or evidence of myocardial ischemia in the presence of ≥ 50% stenosis located in native coronary vessels.
• Written, informed consent by the patient or her/his legally-authorized representative for participation in the study and assessment by OCT.
• In women with childbearing potential a negative pregnancy test is mandatory.

Exclusion Criteria:

• Intervention in the segment of the study stent after the index procedure
• Target lesion located in the left main trunk.
• In-stent restenosis with difficulty to pass the OCT device
• Acute myocardial infarction
• Known allergy to the study medications: Sirolimus, rapamycin, probucol or stainless steel.
• Pregnancy (present, suspected or planned) or positive pregnancy test.
• Patient's inability to fully cooperate with the study protocol.