Good Outcomes of Novel Bioresorbable-Polymer SES Persist at 2 Years

 

A novel sirolimus-eluting stent (SES) with a coating designed for quick polymer absorption but long-term drug delivery has demonstrated good safety and efficacy at 2 years with no evidence of stent thrombosis, according to a study published online September 26, 2015, ahead of print in EuroIntervention.

 

The Take Home 

“Long-term DES safety requires tissue coverage of the stent struts, rapid endothelialization, and sufficient healing,” the study authors say, noting that the MiStent has all of these features.

The MiStent sirolimus-eluting absorbable-polymer coronary stent system (Micell Technologies; Durham, NC) is comprised of sirolimus and polylactide-co-glycolic acid (PLGA) on a cobalt-chromium platform. The sirolimus/PLGA compound is cleared from the platform within 60 days and the PLGA is fully absorbed within 90 days, but the crystalline sirolimus continues to elute into surrounding tissue for up to 9 months.

DESSOLVE I was a first-in-human, single-arm trial that evaluated MiStent in 30 ischemic CAD patients, while the randomized DESSOLVE II trial compared MiStent (n = 123) with the permanent-polymer, zotarolimus-eluting Endeavor Sprint (Medtronic; n = 61). The latter trial showed MiStent to be superior over Endeavor at limiting in-stent late lumen loss at 9 months (P < .001).

Researchers led by William Wijns, MD, PhD, of the Cardiovascular Research Center Aalst (Aalst, Belgium), combined the trial populations to analyze 2-year MACE (death, MI, or clinically driven TVR), target lesion failure (TLF; cardiac death, MI, or clinically driven  TLR), and target vessel failure (TVF; cardiac death, MI, or TVR).

Outcomes Comparable to Endeavor

Only 1 MACE event—a non-Q–wave MI in a non-target vessel—occurred in DESSOLVE I patients by 2 years (3.4%). There were no instances of death, TVR, TLR, TVF, TLF, or stent thrombosis. Median duration of dual antiplatelet therapy (DAPT) was 364 days.

In DESSOLVE II, 2-year MACE and death rates were similar for MiStent and Endeavor, with all deaths occurring more than 30 days after implant. TVR was the only differential outcome between the stent types, with Endeavor carrying a higher rate (table 1).

Table 1. DESSOLVE II: Adjudicated 2-Year Outcomes

There was 1 case of probable/definite stent thrombosis, which occurred in the Endeavor group. Median DAPT duration was identical between the arms (366 days).

More Patients, Longer Follow-up Needed

“Long-term DES safety requires tissue coverage of the stent struts, rapid endothelialization, and sufficient healing,” write Dr. Wijns and colleagues, adding that OCT measurements in DESSOLVE II “revealed high mean rates of stent coverage (97.9%) at 9 months, and the endothelial function studies demonstrated preserved vasomotion both proximally and distally to the stent.”

Limitations of the study, the authors note, are that the operators could not be blinded to the stent type in the randomized trial and that the small population “does not permit comparative analysis of safety outcomes such as [stent thrombosis].” Longer-term follow-up and larger trials in addition to “real-world experience” will provide further insight into the performance of the novel device, they conclude.


Source: 
Wijns W, Suttorp MJ, Zagozdzon L, et al. Evaluation of a crystalline sirolimus-eluting coronary stent with a bioabsorbable polymer designed for rapid dissolution: two-year outcomes from the DESSOLVE I and II trials. EuroIntervention. 2015;Epub ahead of print.

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Disclosures
  • The study was sponsored by Micell Technologies.
  • Dr. Wijns reports receiving institutional grants from several device companies including Medtronic and Micell Technologies and founding, holding shares in, and serving as a nonexecutive board member of Argonauts Partners, Cardio3 BioSciences, and Genae.

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