Short-term stent coverage of second-generation zotarolimus-eluting durable polymer stents: Onyx one-month optical coherence tomography study

Abstract

Introduction: To date the early strut coverage with the second-generation durable-polymer ONYX zotarolimus-eluting stent (O-ZES) is unknown.

Aim: Optical coherence tomography (OCT) assessed the strut coverage of O-ZES at thirty-day follow-up.

Material and methods: OCT was performed after implantation and at 1-month follow-up in 15 patients treated with O-ZES.

Results: Mean patient age was 67 ±7 years (73% males). The clinical presentation consisted of acute coronary syndromes (n = 13) and stable coronary disease (n = 2). Four (26%) patients had diabetes. OCT analysis was performed at baseline and 1-month follow-up in all stents. 378 cross-sections with 3582 struts were assessed at baseline and 3661 at follow-up. At follow-up, 88% struts were covered by tissue with a median thickness 37.91 μm (IQR: 22.32-64.15). Median in-stent area obstruction by neointima was 2.64% (IQR: 1.70-4.84). From the total stent covered area, 92.3% showed complete strut coverage. Homogeneous tissue was observed in 74% of cases. There were no differences in minimal lumen area (5.07 ±1.08 mm² vs. 4.81 ±0.94 mm², p = 0.125) or minimal stent area (4.95 ±1.22 mm² vs. 4.92 ±0.99 mm²) at baseline and at follow-up. There were no differences in the rate of strut malapposition (4.3% vs. 5.7%, p = 0.417). For all stents, malapposition volume was 47.9 mm³ at baseline and 51.7 mm³ at follow-up, giving the late acquired stent malapposition volume of 3.8 mm³.

Conclusions: The second-generation durable polymer O-ZES showed favorable vessel healing at 30-day OCT follow-up.

Keywords: 1-month follow-up; optical coherence tomography; vessel healing; zotarolimus-eluting stent.

Figure 1

Representative OCT images of O-ZES coverage at 30-day follow-up. A, C – Baseline cross-sectional images of the implanted study stent. B – Cross-sectional image of study stent covered with homogeneous neointima. D – Cross-sectional image of study stent covered with heterogeneous neointima

Figure 2

Representative images of O-ZES surface area analysis. A – Cross-sectional image of the implanted stent. B – Boxes indicate the 1 mm intervals of surface measurements. Red color indicates covered struts, other color indicates uncovered struts. C, D, E – Representative images of study stent with lumen surface (white line) covered with uncovered struts (blue boxes)

Figure 3

The proportion of neointimal thickness measured for a single strut