Absolutely Zero Stent Thrombosis at 5 Years With Bioabsorbable MiStent

The MiStent bioabsorbable polymer-based drug-eluting stent (DES) had a favorable long-term safety profile, notably tied to zero occurrences of stent thrombosis, 5-year data from the DESSOLVE I and II studies suggested.

The former, a single-arm study that first tested the MiStent in humans, found that 10.3% had experienced a major adverse cardiac event — two non-target vessel MIs and one clinically-driven target vessel revascularization, according to William Wijns, MD, PhD, of National University of Ireland Galway, and colleagues writing online in EuroIntervention.

None of those enrolled in DESSOLVE I developed stent thrombosis (definite or probable), nor did their peers in DESSOLVE II. In that study, patients randomized to percutaneous coronary intervention with the Endeavor Spring DES had a 1.7% rate of stent thrombosis over 5 years.

Persistent incidence of stent thrombosis loomed large in earning Abbott Vascular’s Absorb bioresorbable scaffold an FDA caution and poor sales.

However, DESSOLVE II did find major adverse events occurring in 15.1% of MiStent recipients (versus 22.0% getting the Endeavor arm, P=0.295); death in 9.2% (versus 10.2%, P=1.000); MI in 5.9% (versus 5.1%, P=1.000); target lesion failure in 9.2% (versus 8.5%, P=1.000); and target vessel failure in 10.1% (versus 15.3%, P=0.331).

Target vessel revascularization after MiStent placement was noted in zero cases in DESSOLVE I and in 3.4% of DESSOLVE II participants receiving the device.

“Five-year follow-up from DESSOLVE I and II show a good safety profile for the MiStents sirolimus-eluting stent, with low rates of target lesion revascularization,” the authors concluded. The investigators acknowledged that neither study was powered for clinical outcomes, however.

 A total of 148 patients were enrolled in the two studies. Wijns and colleagues reported that 5-year follow-up was 96.7% complete for this analysis. By then, dual antiplatelet use was 37.4% and 42.3% for the MiStent and Endeavor groups, respectively.

MiStent features a polylactide-co-glycolic acid coating that is fully absorbed within 90 days; sirolimus crystals are released over up to 9 months. Earlier this year, investigators for the DESSOLVE III trial reported that the MiStent matched the Xience DES in combined 1-year rates of cardiac death, target vessel MI, and clinically-indicated target lesion revascularization.