Sirolimus-eluting vs Zotarolimus-eluting Stents for Chronic Total Coronary Occlusions

Percutaneous coronary intervention (PCI) of chronic total occlusions (CTO) was traditionally limited by high restenosis rates. Coronary stenting using bare metal stents significantly decreases restenosis in CTO compared to balloon angioplasty alone, but restenosis rates still reach 32-55%. In 200 patients with CTO, randomized in the PRISON I study we demonstrated a restenosis rate of 22% after bare metal stent (BMS) implantation as compared with 33% after conventional balloon angioplasty. During the past few years, sirolimus (rapamycin), a cytostatic macrocyclic lactone with anti-inflammatory and antiproliferative properties, delivered from a polymer-encapsulated stent was shown to almost eliminate the risk of restenosis in selected groups of patients. The drug zotarolimus (ABT-578), a sirolimus analogue, is designed to inhibit the cellular process that leads to restenosis. In the PRISON II study we have randomized 200 patients with CTO to either BMS implantation or sirolimus-eluting stent implantation and we demonstrated a reduction of in-stent binary restenosis from 36% to 7% and in-segment binary restenosis rates from 41% to 11% in favour of the sirolimus eluting stent. However, no data are available on direct comparison of the clinical efficacy, safety, and angiographic outcome of particular drug-eluting stents in patients with CTO and there may be differences between various drug-eluting stents. The PRISON III study is designed to address this issue and provide information about two different drug-eluting stents. It is a prospective randomized, single blinded trial comparing the relative safety, clinical efficacy and angiographic outcomes of sirolimus and zotarolimus-eluting stents in patients undergoing successful recanalization of CTO.

Inclusion criteria

• the estimated duration of the occlusion is at least 2 weeks.
• signs of ischemia related to the occluded coronary artery.
• successful recanalization of the occluded artery is achieved.
• reference diameter is > 2.5 mm.
• written informed consent obtained.

Exclusion criteria

• primary or rescue PCI for acute myocardial infarction
• the lesion could not be crossed.
• lesions with complex anatomy making successful stent deployment unlikely.
• the guide wire is not in the true lumen distal to the occlusion.
• Sirolimus or zotarolimus allergy
• venous or arterial bypass grafts
• pregnant or nursing women.
• participation in an other trial.
• factors making long-term follow-up difficult or unlikely.
• life expectancy <1 year.
• contraindications for ASA or Clopidogrel or heparin.
• use of coumadins that could not be stopped before the procedure.