A Study to Examine the Implantation Characteristics of Two Drug-Eluting Stents (ORCA-2)

Comparison of Rates of Strut Malapposition Between Everolimus and Sirolimus Eluting Stents - A Randomised Optical Coherence Tomography Study

Despite recent advances in stent technology and clot reducing drug therapy, acute stent occlusion or thrombosis (ST), still occurs and can be life threatening. It has been shown that certain features of how the stent relates to the artery wall may predict ST. One such feature, so-called stent strut malapposition (SSM), can be assessed after implantation but current imaging techniques are relatively unreliable. Optical Coherence Tomography (OCT) is a newer technology that can be performed safely and easily after angioplasty and may allow the stent struts to be assessed more accurately and reliably. This study will use OCT to examine how two different types of commonly used drug-eluting stents relate to the artery wall. The Xience V (Abbott Vascular, USA) stent has thinner struts and a more open frame than the Cypher (Cordis, USA) stent. We hypothesise therefore that the potentially more pliable structure of the Xience V stent will be associated with greater contact with the vessel wall. This may have a bearing on the relative rate of SSM, although large studies have shown the rate to be low in both the Cypher and the Xience V stent. We believe that OCT imaging of SSM and symmetry of the stent immediately after angioplasty will compliment conventional visual assessment and may identify those patients in whom further improvement of stent with a balloon is necessary. This study will involve the random allocation of forty patients requiring coronary angioplasty to one of the Cypher or Xience V stent. The procedure will be performed in the usual manner as indicated clinically and will include imaging of the stented artery segment with OCT once the operator is satisfied with the visual result by angiography.

Percutaneous Coronary Intervention, Coronary Artery Stenosis, Acute Myocardial Infarction, Coronary Artery Stent, Optical Coherence Tomography

Participants in the Cypher arm will be randomised to receive a Cypher™ (Cordis, Miami Lake, USA) coronary stent

The angioplasty will then be performed in a usual fashion in accordance with the operator's discretion and local protocols.

The angioplasty will then be performed in a usual fashion in accordance with the operator's discretion and local protocols

SSM will be quoted as the percentage of malapposed stent struts as a proportion of the total number of struts analysed within each stent group.

This is a commonly used measure that is designed to quantify the uniformity and symmetry of the stent after it has been deployed in the coronary artery. It is calculated as the minimum diameter of the stent divided by the maximum diameter of the stent at a preset point. The mean SEI will be compared between two stent type groups.

This relates to what degree, if at all, the stent strut is 'buried' within the coronary artery wall. The proportion of each strut that is buried or embedded will be calculated and then averaged for each stent group. A strut that is buried in the vessel wall for more than half its thickness will be defined as 'embedded'.

Inclusion Criteria: Presence of a coronary artery stenosis undergoing percutaneous coronary intervention and stenting (PCI). Eligibility for drug eluting stent (DES) deployment. Stable or unstable coronary syndrome presentation, including ST elevation myocardial infarction (STEMI). Aged 18-90 Exclusion Criteria: Contraindication to the use of a DES. Target lesion located within previous stent (in stent restenosis). Sustained haemodynamic instability following stent deployment (Systolic BP 90≤ mmHg or sustained ventricular arrhythmia).