Test Efficacy With Bioresorbable Polymer Coating Versus Bioresorbable Polymer Backbone (ISAR-RESORB)

A Prospective, Randomized Trial of SYNERGY Bioresorbable Polymer Coated Stents Versus ABSORB Bioresorbable Backbone Stents in Patients Undergoing Coronary Stenting (ISAR-RESORB)

The bioresorbable polymer SYNERGY EES exhibits a favourable vascular healing profile in patients undergoing coronary intervention for de novo lesions. Specifically, the SYNERGY EES is superior to the ABSORB bioresorbable vascular scaffold in terms of antirestenotic efficacy as assessed by angiography at 6-8 months.

Percutaneous coronary intervention (PCI) with drug-eluting stent (DES) implantation currently represents the dominant treatment strategy in patients undergoing catheter intervention. However, effective neointimal suppression occurs at the cost of a systematic delay in arterial healing in comparison with after bare metal stenting. This underlies a small but significant increased risk of stent thrombosis after DES implantation in comparison with bare metal stent implantation as well as a possible excess of in-stent neoatheroma formation. To address this issue recent technological advances have focused on bioresorbable polymer coatings and the development of stents with fully resorbable backbones.

Newer generation metallic DES with bioresorbable polymer coatings have been shown to improve vascular healing after coronary stenting. In particular a novel thin-strut bioresorbable polymer everolimus-eluting stent (EES, SYNERGY, Boston Scientific Corp., Natick, MA, USA) has shown high angiographic antirestenotic efficacy as well as high clinical efficacy and safety in early randomized trials. In addition, DES with bioresorbable backbones represent an alternative approach to ensure short-term vessel scaffolding and drug delivery with enhanced vessel healing. The everolimus-eluting bioresorbable backbone stent (ABSORB bioresorbable vascular scaffold [BVS], Abbott Vascular, Santa Rosa, CA, USA) is the most-extensively studied device in this class and early reports in selected patients show encouraging clinical results. However requirement for thicker stent struts and more careful lesion preparation has led to concerns that potential clinical benefits may be offset by erosion of early antirestenotic efficacy and occurrence of clinical events related to limitations of device deployment.

At present there is a lack of randomized clinical trial data examining outcomes of patients treated with these two alternative strategies. The aim of the current ISAR-RESORB study is to test the clinical performance of the bioresorbable-polymer SYNERGY with that of the ABSORB BVS in patients undergoing PCI of de novo coronary lesions. The primary endpoint will be percentage diameter stenosis at protocol-mandated 6-8 month angiographic follow-up. Secondary clinical endpoint will be assessed at 12 months. Sample size calculation is based on a superiority hypothesis for SYNERGY versus ABSORB BVS. It is planned to enrol a total of 230 patients.

Inclusion Criteria:

• Patients 18 years or older with ischemic symptoms or evidence of myocardial ischemia in the presence of ≥ 50% de novo stenosis located in native coronary vessels (max. 2 lesions in 2 separate vessels)
• Reference diameter ≥2.5 mm and ≤3.9 mm
• Lesion length <28 mm
• Written, informed consent by the patient for participation in the study

Exclusion Criteria:

• Cardiogenic shock
• Acute ST-elevation myocardial infarction within 48 hours from symptom onset.
• Target lesion located in left main trunk or bypass graft
• Severe calcification of the lesion
• Target lesion contains a side branch (diameter ≥2mm) or a bifurcation or is located 2 mm away from a bifurcation
• Ostial lesions
• Severe vessel tortuosity
• Renal insufficiency (most recent serum creatinine within the last 72h prior to randomization > 2 mg/dl or 177 µmol/l)
• Malignancies or other co-morbid conditions with life expectancy less than 12 months or that may result in protocol non-compliance
• Pregnancy, present (positive pregnancy test), suspected or planned, breast feeding
• Contraindications or allergy to platinum, chromium, everolimus or the inability to take antiplatelet therapy for at least 6 months after stenting; known allergy to PLLA, PDLLA or PLGA polymer
• Previous enrollment in this trial
• Patient's inability to fully cooperate with the study protocol