First-in-human evaluation of a sirolimus-eluting coronary stent on an integrated delivery system: the DIRECT study

Abstract

The DIRECT study is a first-in-human evaluation of the safety and efficacy of the Svelte sirolimus-eluting coronary stent mounted on a fixed-wire, "all-in-one" integrated delivery system (IDS) in patients with de novo coronary artery lesions. The system permits easy delivery, deployment and post-dilatation of a cobalt-chromium stent eluting sirolimus from a fully bioabsorbable amino acid coating. The stent on its IDS has a very low profile, and is designed specifically to facilitate direct stenting. Patients with symptomatic ischaemic heart disease and a single de novo native coronary lesion suitable for percutaneous coronary intervention were prospectively enrolled at four New Zealand sites. The lesion length had to be <23 mm and the vessel reference diameter 2.5-3.5 mm. The primary safety and efficacy endpoints were target vessel failure (TVF) and angiographic in-stent late lumen loss (LLL) at six months, respectively. Twenty-nine of 30 enrolled patients completed six-month follow-up. TVF occurred in two patients (7%). The in-stent LLL was 0.22 ± 0.27 mm. No patient had clinically-driven target lesion revascularisation. Intravascular ultrasound neointimal volume was 3.3 ± 4.4 mm3 and volume obstruction was 2.7 ± 4.5% at six months. Optical coherence tomography showed 98 ± 4% strut coverage at a depth of 0.12 ± 0.06 mm. No patient developed stent thrombosis. Percutaneous coronary intervention using the Svelte sirolimus-eluting coronary stent mounted on an IDS appears safe and effective in de novo coronary artery lesions, with minimal in-stent proliferation and excellent stent strut coverage at six months.