Objective: We used intravascular ultrasound (IVUS) to compare restenotic sirolimus-eluting (SES) vs paclitaxel-eluting (PES) stents.
Background: Little is known about the IVUS pattern and mechanisms of restenosis, in the two widely available drug-eluting stent (DES) platforms.
Methods: Volumetric IVUS analysis was performed in patients with clinical restenosis in DES (n=29 SES and 11 PES respectively).
Results: Despite similar vessel volumes (347.5+/-155.6 vs 356.5+/-164.1 mm(3), p=0.84) and stent volumes (175.6+/-74.57 vs 179.7+/-84.24 mm(3), p=1.0), IVUS analysis showed that neointimal hyperplasia volume was significantly greater in PES restenoses than in SES restenoses (40.0+/-44.2 vs 19.3+/-11.4 mm(3), p=0.02) without any significant difference in distribution over the stent length. This leads to a higher percent of volume obstruction (intimal hyperplasia volume divided by stent volume: 18.5+/-13.7% vs 11.8+/-7.7%, p=0.045). Minimal stent area was smaller in SES than in PES (4.3+/-1.2 vs 5.6+/-1.2 mm(2), p=0.06) and stent underexpansion was more frequently observed in SES stents: minimal stent area <4.5 mm(2) (65% in SES vs 27% in PES, p=0.04). Stent edge restenosis occurred in 1/29 SES (3%) vs 3/11 PES (27%) stents, p=0.056.
Conclusion: The magnitude of neointimal hyperplasia was greater in PES than in SES while stent underexpansion appeared to be more common in SES.