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A novel bioresorbable stent failed to meet the threshold for noninferiority compared with durable devices in the OPTIMIZE trial, and researchers suggested rising troponin use may have played a role.

The Svelte stent, designed to facilitate direct stenting and transradial access in percutaneous coronary intervention (PCI), did not differ significantly from metallic everolimus-eluting stents with respect to 1-year target lesion failure (10.3% vs 9.5% on intention-to-treat analysis) or its individual components:

• Cardiac death (0.25% vs 0.26%)
• Target vessel MI (9.4% vs 8.2%)
• Clinically indicated target lesion revascularization (1.5% vs 1.9%)

Nevertheless, the Svelte did not meet prespecified noninferiority criteria, given both groups' unexpectedly high target vessel MI rates that left the study underpowered, reported Dean Kereiakes, MD, of the Christ Hospital in Cincinnati, Ohio, and colleagues in .

Indeed, a noninferiority margin of 3.58% had been calculated based on an expected event rate of 6.5% for the trial.

Kereiakes and team said that post-hoc analyses, using MI definitions adjusted for troponin elevation, supported noninferiority of the Svelte compared with control stents.

They noted that failure to meet prespecified noninferiority could be attributed in part to both the more sensitive troponin biomarker and the specific protocol definition of target vessel MI, which did not account for rising troponin use in clinical practice.

Identified target vessel MIs were largely periprocedural, and the vast majority did not result in ECG changes from baseline, the authors reported.

"Standardization of biomarkers and MI definitions across DES [drug-eluting stent] studies are needed to limit the impact of the increased utilization of troponin and high-sensitivity biomarkers in clinical practice," they wrote.

The Svelte is a novel sirolimus-eluting bioresorbable stent with struts measuring 81 µm. The drug is eluted over 60 days, and polymer resorption is expected within 12 months.

The device represents another foray into the arena of bioresorbable stents following the cautionary tale of Absorb, which was famously foiled by stent thrombosis. Abbott pulled the Absorb bioresorbable vascular scaffold from the market in 2017.

In OPTIMIZE, stent thrombosis rates were no different between the bioresorbable and metallic stent groups (0.38% vs 0.51%, P=0.72).

Other bioresorbable stents under investigation by other groups include the second-generation Firesorb.

was conducted at 74 sites enrolling patients scheduled for PCI for non-ST-segment elevation myocardial infarction (NSTEMI) or stable coronary artery disease in 2018-2019.

Investigators randomized 1,639 individuals to the Svelte stent or a durable polymer everolimus-eluting stent (i.e., Xience or Promus).

Baseline characteristics were well matched between groups. Mean age was 65 years, and men made up approximately 71% of the cohort.

Operators opted for the transradial approach in four out of five cases. Consistent with other studies, transradial access was associated with reduced access site hematoma and acute kidney injury compared with transfemoral access, according to Kereiakes and colleagues.

In a subgroup of 132 patients who underwent quantitative coronary angiography at 12 months' post-procedure, the Svelte was noninferior to controls for in-stent late lumen loss at 1 year (0.29 mm vs 0.21 mm).

Intravascular ultrasound found the Svelte to have the advantage of less incomplete stent apposition, which the study authors suggested may relate to both the low-compliant delivery balloon and higher deployment pressures used in the system.

Limitations of OPTIMIZE included its single-blind design and the exclusion of complex patient and lesion subsets, which may have affected the generalizability of the results.

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