Evaluation of Zotarolimus Eluting Stent at 3 Months Using Optical Coherence Tomography
Condition: Coronary Artery Disease
MeSH terms: Coronary Artery Disease; Myocardial Ischemia; Coronary Disease
Study type: Observational

Summary: 
      Neointimal coverage over stent strut is important for preventing the stent thrombosis. But,
      there is no data for the duration of complete formation of neointima om zotarolimus eluting
      stent (ZES). Previously the investigational observational data at 9 months showed most of
      stent strut was covered with neointima. Therefore, the investigators investigated the
      evaluation of neointimal coverage on 3 months after ZES implantation using novel OCT system,
      which is powerful intravascular imaging system having the higher resolution power.
    

Detailed description: 
      Stent thrombosis is current main issue after introduction of drug-eluting stents and
      theoretically dual antiplatelet therapy should be continued to prevent the stent thrombosis
      until complete reendothelization. Currently, AHA/ACC guideline recommend dual antiplatelet
      should continue at least 3 months in Sirolimus eluting stent (SES) and 6 months in paclitaxel
      eluting stent (PES), but if possible, suggest to use until 12 months.

      Zotarolimus (Endeavor®) eluting stent (ZES) have been recently introduced and focused on
      reducing concern of safety through the biocompatible polymer and rapid drug elution. ENDEAVOR
      II trial showed a 0.5 per cent rate of stent thrombosis at 30 days - with no late thrombosis
      beyond 30 days and no late stent malapposition. In the long term follow up data of Endeavor
      stent, the two-year clinical results of ENDEAVOR I were impressive, with a low TVF and MACE
      rate (2% and 3% respectively) with the absence of reported thromboses after day 14. These
      results speak, especially the lack of stent thrombosis after 14 days, reflect very well on
      the performance and safety of the ZES.

      But, there has been no guideline for the duration of dual antiplatelet therapy in ZES
      although shorter duration of dual antiplatelet therapy could be safe compared to previous
      drug-eluting stents. Also, there is no data how long duration might be taken in completion of
      reendothelialization after ZES implantation in living patients. The most powerful
      histological predictor of stent thrombosis was endothelial coverage. The best morphometric
      predictor of LST was the ratio of uncovered to total stent struts. Because the presence of
      endothelization is not available in in vivo situation and endothelialization is reported to
      be associated with neointimal coverage of stent, the detection of neointima after stent
      implantation could be the main issue to predict the stent thrombosis. Recent data in SES
      using optical coherence tomography (OCT) reported neointimal coverage over a SES at 3-month
      follow-up is incomplete. The rates of exposed struts and exposed struts with malapposition
      were 15% and 6%, respectively. These were more frequent in patients with acute coronary
      syndrome (ACS) than in those with non-ACS (18% vs 13%, p <0.0001; 8% vs 5%, p <0.005,
      respectively).

      Although neointimal coverage could be completely in early period after ZES implantation,
      there is no data for this finding. Therefore, we investigate the evaluation of neointimal
      coverage on 3 months after ZES implantation using novel OCT system, which is powerful
      intravascular imaging system having the higher resolution power. This study may provide
      adequate information on the safety of discontinuation of dual antiplatelet therapy for
      patients in clinical situations.
    

Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients who present to the cath lab for non-emergent percutaenous coronary intervention
        and stenting are eligible for participation
      
Biospecimen description: 
      Blood
    
Keywords: Coronary artery disease, stent