Improved Target Lesion Failure Rates With Ultrathin-Strut Biodegradable Stent

At 3 years, patients with acute coronary syndrome treated with ultrathin-strut biodegradable polymer sirolimus-eluting stents with a sustained drug release system have a significantly better target lesion failure rate compared with patients treated with thick-strut biodegradable polymer biolimus-eluting stents, according to study findings published in Circulation: Cardiovascular Interventions.

Researchers sought to compare long-term clinical outcomes of patients with a high prevalence of acute coronary syndrome treated with an ultrathin-strut stent vs a thick-strut stent.

They conducted the BIODEGRADE (BioMatrix and Orsiro Drug-Eluting Stents in Angiographic Result in Patients with Coronary Artery Disease; ClinicalTrials.gov Identifier: NCT02299011) trial, a prospective, randomized, open-label, multicenter study comparing revascularization in patients with thick-strut stents and patients with ultrathin-strut stents between July 2014 and September 2017. The primary outcome was target lesion failure.

Patients (N=2341) were randomly assigned in a 1:1 ratio to receive treatment with an ultrathin-strut stent (n=1175; 1526 lesions) or a thick-strut stent (n=1166; 1512 lesions). There was no significant difference in lesion characteristics or treatment procedures between the 2 treatment groups other than maximal pressure, which was significantly lower in the thick-strut stent group. After withdrawals, missed exclusions, and loss to follow-up, the analysis included 1167 patients with 1516 lesions in the ultrathin-strut stent group and 1160 patients with 1506 lesions in the thick-strut stent group. Exclusion criteria included cardiogenic shock, symptomatic heart failure, and noncardiac comorbid conditions resulting in life expectancy of less than 1 year.

Overall, patients had a mean age of 63.5±10.9 years and 28.1% were women. Common comorbidities included arterial hypertension (59.8%), dyslipidemia (53%), and diabetes (33.4%). There were 27% current smokers and 12% had previous percutaneous coronary intervention. There were 27.6% with stable angina and 36.5% with unstable angina. There was 1 target lesion per patient in 73.4% of the patients and 2 lesions in 20.5%. At discharge, patients were on clopidogrel (82.6%), renin-angiotensin system inhibitors (63.5%), and beta-blockers (63%). All of these patient characteristics were well-matched between treatment groups.

For the ultrathin-strut stent group, the 3-year incidence rate of target lesion failure was 3.2%. For thick-strut stent group, the 3-year incidence rate of target lesion failure was 5.1% (P =.023). The researchers noted that this primary difference was most likely due to differences in ischemia-driven target lesion revascularization (ultrathin-strut stent, 1.5%; thick-strut stent, 2.8%; P =.035) between groups.

Subgroup analysis showed consistency for target lesion failure outcomes except for diabetes. Target lesion failure occurred less frequently in the ultrathin-strut stent group in patients without diabetes than in the thick-strut stent group (hazard ratio, 0.33; 95% CI, 0.18-0.62; P =.001, P for interaction =.004).

Study limitations include the limited statistical power for comparisons of selected end points and selection bias. Additionally, 1 of the stents was replaced with a newer version by the manufacturer.

“In patients with a high prevalence of acute coronary syndrome, the thin-strut BP-SES [biodegradable polymer sirolimus-eluting stent] with sustained drug release system showed superior outcomes compared to the thick-strut BP-BES [biodegradable polymer biolimus-eluting stent] with the standard drug release system with respect to clinical outcomes (TLF [target lesion failure]) at prespecified 3-year follow-ups,” the researchers wrote. “This is a remarkable finding, showing that the substantial differences in strut thickness and stent design may be contributing factors to the long-term clinical outcomes of stents.”

Disclosure: This research was supported by BIOTRONIKS KOREA (Seoul, Republic of Korea) and DIO KOREA (Seoul, Korea). Please see the original reference for a full list of disclosures.