Previous research shows that different stents yield different outcomes. One randomized comparison of 5 stents showed a striking variation in angiographic restenosis rates (25% to 36%) and target vessel revascularization rates (14% to 29%). These differences suggested specific stent characteristics could affect the development of restenosis.

Subsequently, investigators compared two stents with similar design, but different strut thickness in a trial named Intracoronary Stenting and Angiographic Results-Strut Thickness Effect on Restenosis Outcome (ISAR-STEREO).

One stent was a first generation Multi-Link^TM. It had very thin struts (50 microns). The other, a second generation Multi-Link Duet, had a strut thickness of 140 microns. At 6 months, there was significantly less restenosis and target vessel revascularization with the thinner strut stents.

The goal of ISAR-STEREO-2 was to assess restenosis and long-term outcome in stents of different design. Investigators from four German centers randomized 611 patients to receive the same thin strut Multi-Link stent, or a thick strut stent of different design (Cordis BX Velocity).

The Multi-Link stent has characteristic interconnected rings, while the Cordis stent has a closed cell, flexible segment design.

All patients had to have symptomatic coronary artery disease and lesions in native coronary vessels no larger than 2.8 mm. The primary endpoint was rate of angiographic restenosis at 6 months. There were no significant differences between patient characteristics or cardiovascular risk factors.

Significantly more patients in the thin strut stent group had ACC/AHA classification B2 or C lesion types. On the other hand, there were more chronic occlusions in the thick strut stent group.

At 6 months, the rate of angiographic restenosis was 17.9% in the thin strut stent group and 31.4% in the thick strut stent group (P < 0.001), a 43% reduction.

A secondary endpoint was clinical restenosis at 6 months. The target vessel revascularization rate was 12.3% for the thin strut stent group and 20.9% for the thick strut stent group (P = 0.002), a 44% reduction.

Another secondary endpoint was survival free of myocardial infarction at 12 months, but there was no significant difference between the thin strut group (95.1%) and the thick strut group (93.7%).

Experts once assumed that the most important factors in restenosis were lesion characteristics, implant techniques and other nuances. Now, ISAR-STEREO-2 suggests stent thickness and design may have an enormous impact.

Cordis Germany partially funded this study.