Novel bioresorbable scaffold holds promise for treating coronary lesions

A novel, sirolimus-eluting bioresorbable scaffold (BRS) has demonstrated potential in treating single coronary lesions, holding promise in vascular restoration therapy, the RENASCENT II* trial has shown.

“BRSs represent the latest innovation in the field of [percutaneous coronary intervention (PCI)],” said the researchers. However, despite their ability to restore vessel lumen and vascular function, BRSs are limited by thicker struts and reduced radial strength, expansion capabilities, and resistance to fracture, they added.

This first-in-human study gauged the performance of APTITUDE^® – a thin-walled BRS with greater mechanical strength, expansion capabilities, and resistance to fracture. Sixty PCI-eligible patients (mean age 65 years, 78 percent male) were evaluated. [EuroIntervention 2020;16:e133-e140]

Clinical device success rate was 98 percent, while procedural success rate was 100 percent. In-scaffold late lumen losses were 0.35 mm and 0.37 mm at 9 and 24 months, respectively.

Target vessel failure** (TVF) rate was low at 9 months (n=2). By month 24, no other cases of TVF, major adverse cardiovascular events, or stent thrombosis were reported. Despite two cases of binary stenosis, these were asymptomatic and required no intervention.

Strut coverage and apposition are considered important predictors of late stent thrombosis, noted the researchers. In the OCT*** analysis, nearly all struts were covered by neo-intimal tissue (97 percent) and completely apposed to the vessel wall (96 percent). “[T]he high percentage of strut apposition and very low percentage of uncovered malapposed struts [in our study] may result in improvement in long-term clinical outcomes,” they said. However, serial imaging is warranted owing to the presence of stent struts at 9 months (indicative of ongoing active resorption), they noted.

“[Taken together,] our analysis demonstrated that the APTITUDE^® BRS is safe and effective for use in the treatment of de novo stenotic native coronary artery lesions in patients undergoing elective PCI,” said the researchers. Larger studies with longer follow up using standard implantation techniques are recommended to further ascertain the device’s efficacy and safety, they added.

Regaining a foothold

The increasing stent thrombosis rates associated with BRS have led to the subsequent withdrawal of some products from the market. [JACC Cardiovasc Interv 2016;9:12-24] European guidelines have also been updated to recommend against use of BRS outside clinical trials. [EuroIntervention 2019;14:1435-534]

These setbacks have blocked the road towards restoring clinicians’ trust in BRS technology, noted Drs Ron Waksman and Brian Forrestal from MedStar Washington Hospital Center in Washington, DC, US, in an editorial. [EuroIntervention 2020;16:e103-e105]

RENASCENT II underlined critical aspects tied to BRS technology: patient and lesion selection, implantation technique, and long-term dual antiplatelet therapy. “[Moreover, the exclusion of] high-risk groups^# [suggest] that we might be closer to finding the correct niche for BRS – stable patients with simple, discrete, de novo lesions,” said Waksman and Forrestal.

“[While] we may have sounded the death knell too soon on this technology, … [RENASCENT II] provides hope that [recent advances] are beginning to bear fruit,” they said. The continued evolution in this field may thus help restore the waning trust, they added.

“Ultimately, we need well-powered ... trials for BRS technology to re-enter clinical practice. Those designing these trials must give careful thought to the comparator (eg, drug-eluting stents vs drug-coated balloons), inclusion/exclusion criteria, and the future role of BRS in the landscape of PCI,” they concluded.