• Interventional Techniques & Devices
• Cardiology Clinical Trials

Durable polymer coatings on drug-eluting stents are associated with chronic inflammation and impaired healing. The reduced polymer load and short-term polymer exposure of bioabsorbable polymer stents may reduce duration of dual antiplatelet therapy (DAPT), reduce risk with DAPT interruption, and decrease stent thrombosis.

The SYNERGY stent has a PLGA bioabsorbable polymer coating plus everolimus that is applied only to the abluminal surface of a thin-strut platinum chromium stent. Once implanted, the polymer coating completely resorbs within 4 months. The Randomized Evaluation of a Novel Bioabsorbable Polymer-Coated, Everolimus-Eluting Coronary Stent (EVOLVE) trial, presented by Ian Meredith, MBBS, PhD, Monash Medical Centre and Southern Health, Melbourne, Australia, compared the bioabsorbable polymer SYNERGY Everolimus-Eluting Coronary Stent System with the permanent polymer PROMUS Element Stent for the treatment of de novo atherosclerotic lesions.

Two SYNERGY bioabsorbable stents were compared with the PROMUS Element permanent polymer stent. One SYNERGY stent had an everolimus dose and release profile that was similar to that of the PROMUS Element. The SYNERGY ½ Dose had half the dose of everolimus and a similar release profile to the PROMUS Element. Patients with de novo native coronary lesions (≤28 mm in length, reference vessel diameter ≥2.5 mm and ≤3.5 mm, %DS >50) were randomized to receive the PROMUS Element (n=98), SYNERGY (n=94), or SYNERGY ½ Dose (n=99). The primary clinical endpoint was target lesion failure (TLF) at 30 days, defined as target vessel cardiac death, target vessel myocardial infarction (MI), or target lesion revascularization. The primary angiographic endpoint was in-stent late loss at 6 months. The study was designed to demonstrate that the SYNERGY stent was noninferior to the PROMUS Element.

Both SYNERGY and SYNERGY ½ Dose stents were noninferior to the PROMUS Element with respect to late loss at 6 months (0.10 vs 0.13 vs 0.15; p=0.19 and p=0.13, respectively, for the SYNERGY and SYNERGY ½ Dose stents compared with PROMUS). Similarly, at 30 days, the SYNERGY and SYNERGY ½ Dose stents were both noninferior compared with the PROMUS Element with respect to TLF (1.1% vs 3.1% vs 0%; p=0.49 and p=0.25, respectively).

Clinical events were infrequent (Table 1) and did not differ between stent types.

This study was limited by the small sample size, and therefore, the study lacked the power to detect differences in low-frequency clinical endpoints, such as stent thrombosis, death, and MI. This study population was a relatively low-risk cohort, limiting generalizability. Two future studies are planned that are powered to assess clinical event rates and optimal duration of DAPT.

The results of this trial show that the 2 dose formulations of the SYNERGY stent were noninferior to the PROMUS Element stent for both the primary clinical endpoint of TLF at 30 days and the primary angiographic endpoint of in-stent late loss at 6 months. Clinical events were low overall, with no stent thrombosis in any group. These results support the safety and potential efficacy of the novel, abluminal, bioabsorbable polymer SYNERGY everolimus-eluting stent for the treatment of patients with de novo coronary artery disease. Additional research is needed to evaluate clinical event rates and the potential for DAPT reduction with this novel stent.

• © 2011 MD Conference Express