Mechanical performance and healing patterns of the novel sirolimus-eluting bioresorbable Fantom scaffold: 6-month and 9-month follow-up by optical coherence tomography in the FANTOM II study

OBJECTIVES: We aimed to evaluate the mechanical properties and healing patterns 6 and 9 months after implantation of the sirolimus-eluting Fantom bioresorbable scaffold (BRS). BACKGROUND: The Fantom BRS (Reva Medical, San Diego, USA) has differentiating properties including radiopacity, strut thickness of 125 µm, high expansion capacity and has demonstrated favourable mid-term clinical and angiographic outcomes. METHODS AND RESULTS: FANTOM II was a prospective, single arm study with implantation of the Fantom BRS in 240 patients with stable angina pectoris. Guidance by optical coherence tomography (OCT) was encouraged and was repeated at 6-month (cohort A) or 9-month follow-up (cohort B). Matched baseline and follow-up OCT recordings were available in 152 patients. In-scaffold mean lumen area in cohort A was 6.8±1.7 mm(2) and 5.7±1.4 mm(2) at baseline and follow-up (p<0.0001) and was 7.2±1.6 mm(2) and 5.6±1.4 mm(2) in cohort B (p<0.0001). Mean scaffold area remained stable from 7.1±1.5 mm(2) at baseline to 7.2±1.4 mm(2) at 6 months (p=0.12), and from 7.4±1.5 mm(2) to 7.3±1.4 mm(2) at 9 months. Strut malapposition was median 0.8 (IQR 0.0;3.5)% and 1.8 (IQR 0.3;6.0)% at baseline and was 0.0 (IQR 0.0;0.0)% in both groups at 6-month and 9-month follow-up. Strut tissue coverage was 98.1 (IQR 95.9;99.4)% at 6 months and 98.9 (IQR 98.3;100.0)% at 9 months. CONCLUSIONS: The novel Fantom BRS had favourable healing patterns at 6-month and 9-month follow-up as malapposition was effectively resolved and strut coverage was almost complete. The scaffold remained stable through follow-up with no signs of systematic late recoil.