Aims: The Endeavor I study was the first clinical study evaluating the safety and feasibility of the Endeavor stent system in the treatment of symptomatic coronary artery disease. The Endeavor Stent System comprises a new cytostatic, antiproliferative and immunosuppressive agent in the same class of drugs as sirolimus, (ABT-578), a phosphorylcholine polymer-based coating, and an established cobalt-alloy stent with thin struts, (Driver stent).
Methods and results: One hundred consecutive patients with symptomatic ischemic heart disease due to de novo, obstructive lesions of native coronary arteries were treated with the Endeavor stent system at eight centers in Australia and New Zealand according to contemporary practice. The acute lesion, procedure, and device-deployment success rates were all 100%. Independent core laboratories analyzed quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS) data immediately after stent implantation, and at 4 and 12 month follow-up. At 12 months, in-stent late lumen loss was 0.61+/-0.44 mm; in-segment late lumen loss was 0.43+/-0.44 mm, and neointimal hyperplasia volume was 14.2+/-11.8 mm3 (corresponding to a percent volume obstruction of 9.7%+/-8.5%). By QCA and IVUS, the pattern of neointimal hyperplasia was greatest within stent and not at the stent edges. The binary angiographic restenosis rate (defined as >50% diameter stenosis) at 4 and 12 months was 2.1% (2/97) and 5.4% (5/93) respectively. The cumulative incidence of major adverse cardiac events (MACE, defined as death, myocardial infarction, emergent cardiac surgery or repeat revascularization of the index lesion), was 1% at 30 days and 2% at 4 and 12 months.
Conclusion: This 100 patient pilot study demonstrates that the Endeavor stent system is a reliable and safe treatment for obstructive coronary disease, providing durable event free clinical outcomes to 12 months by suppression of neointimal proliferation of the target lesion. The results support further pivotal evaluation in larger randomized clinical trials.