STACCATO: Stent sTrut Apposition and Coverage in Coronary ArTeries: an Optical Coherence Tomography (OCT) Study

• The use of DES in STEMI and NSTEMI is still a matter of intense debate. Reassuring data of trials, meta-analyses and registries conflict with reports of delayed arterial healing and higher risk of stent thrombosis after DES implantation in ACS patients. Heterogeneity in healing (bad healing at the site of the necrotic core), stent strut malapposition and plaque prolapse are all proposed as possible causes for a higher risk of stent thrombosis. Furthermore, next generation DES claims a better safety profile in comparison to first-generation DES.
• Thus far, our information on tissue characterisation of coronary plaques prone to rupture, relies on histopathology data. Recently, new invasive coronary imaging techniques; radiofrequency intravascular ultrasound (RF-IVUS) and optical coherence tomography (OCT) provide new possibilities for in vivo assessment of coronary plaques.

Aims:

• To evaluate vessel healing, expressed as stent strut coverage and stent strut apposition assessed with OCT at 9 months after PCI and compare between everolimus Xience V (Abbott Vascular, Santa Clara, CA) and biolimus A9-eluting Biomatrix (Biosensors, Newport Beach, CA) stents, in 3 different groups of patient subsets (STEMI, NSTEMI and patients with stable/unstable angina).
• To make, by use of OCT and IVUS-TC, a detailed characterisation of coronary lesions before PCI and to study the possible link between specific lesion characteristics (e.g. thin cap fibroatheroma, large necrotic core, extensive calcification,…) and outcome (risk of distal embolisation and myonecrosis in the short term, risk of bad strut coverage or risk of restenosis or stent thrombosis on longer term). To compare the performance of both technologies (OCT and IVUS-TC) in a direct way.
• To assess, by use of OCT and IVUS-TC, the stented segment just after the intervention (assessment of stent expansion, stent strut apposition, detection of edge dissection, intraluminal thrombus) and correlate with angiographic and clinical outcomes. Again, the performance of both technologies will be compared in a direct way.
• To study the influence of drug-eluting stent implantation in a 3-5 cm long segment of the coronary artery just distal to the implanted stent by use of OCT at baseline and at 9 months after stent implantation.

Methods: Patients undergoing PCI are recruited from 3 groups of patients: patients with STEMI (group I), patients with NSTEMI (group II) and patients with stable/unstable angina (group III). From each group, 20 patients are included. In each individual group, randomization between an everolimus-eluting stent and a biolimus A9-eluting stent is performed. All patients undergo IVUS-TC and OCT examination of the stented segment (and the 3 to 5 cm distal from the stented segment) just before and after stent implantation at the time of the index procedure. All patients undergo control angiography with OCT examination at 9 months follow-up.

Inclusion criteria

• Patient older than 18 years
• Written informed consent available
• Patient eligible for percutaneous coronary intervention
• patients with a single or multiple de novo lesion(s) from 3 different patient subsets (STEMI, NSTEMI, stable/unstable angina). Target reference vessel diameter measured by QCA: 2-4 mm

Exclusion criteria

• Left ventricular ejection fraction of < 30%
• Hemodynamic unstability (cardiogenic shock, life-threatening arrhythmias, inotropic support)
• Impaired renal function (serum creatinine > 2.0 mg/dl)
• Target lesion located in bifurcation
• Lesion of the left main trunk > 50%, unprotected
• Known allergies to antiplatelet, anticoagulation therapy, contrast media, everolimus or biolimus A9
• Pregnant and/or breast-feeding females or females who intend to become pregnant (pregnancy test required)
• Patients with a life expectancy of less than one year
• Patient currently enrolled in other investigational device or drug trial
• Patient not able or willing to adhere to follow-up visits