Intracoronary Stenting and Angiographic results - Strut Thicness Effect on Restenosis Outcome Trial - 2 - ISAR-STEREO - 2
The goal of ISAR-STEREO 2 was to assess the impact of stent strut thickness on the rate of angiographic restenosis in patients with symptomatic coronary artery disease undergoing intracoronary stent implantation.
Use of a reduced stent strut thickness will be associated with reduced rates of angiographic and clinical restenosis.
Patients Enrolled: 611
Mean Follow Up: 6 months
Mean Patient Age: mean age 66 years
Symptomatic coronary artery disease and coronary lesions situated in native vessels
Angiographic restenosis, defined as 50% diameter stenosis at follow-up angiography
Target-vessel revascularization (TVR); composite of death and MI at 1 year
Patients with symptomatic CAD and lesions in a native coronary arteries were randomized to implantation of a thin strut stent (50 µm thickness, n=309) or a thick strut stent (140 µm thickness, n=302).
Heparin and aspirin IV during the procedure, and abciximab in patients considered at a higher risk for thrombotic events. Post-procedural, aspirin (100 mg twice daily indefinitely) and clopidogrel (75 mg/day for at least 4 weeks).
Vessel size (2.93 mm for thin-strut vs 2.91 for thick-strut, p=0.68), lesion length (13.9 mm vs 14.1 mm, p=0.77) and diameter stenosis (68.2% vs 70.8%, p=0.11) were comparable in the two groups, as was the rate of use of glycoprotein IIb/IIIa platelet inhibitors (50% vs 49%, p=0.9). Procedural success was >99% in each stent group. Quantitative coronary angiography at 6 months revealed a greater minimum lumen diameter and less late loss in the patients receiving the thin strut stents vs the thick strut stents (MLD 1.96 mm vs 1.70 mm, p<0.001; late loss 0.93 mm vs 1.19 mm, p<0.001). Angiographic restenosis occurred in 17.9% of the thin-strut group and 31.4% of the thick-strut group (relative risk 0.57, 95% CI 0.39-0.84; p<0.001). Clinical restenosis (target vessel revascularization) was also significantly less with the thin strut stents (12.3% vs 20.9%, RR 0.56, 95% CI 0.38-0.84, p=0.002). There was no significant difference in the composite rate of death or MI at 1 year (4.9% thin strut vs 6.3% thick strut, RR 0.77, p=0.46).
Among patients with symptomatic coronary artery disease and native coronary lesions, a reduced stent strut thickness was associated with reduced rates of angiographic and clinical restenosis at 6 month follow-up. Despite these provocative results, the thin-strut stent model used in this trial is no longer commercially available. Other prior clinical trials have demonstrated that stent characteristics such as stent architecture, composition of stent surface, and strut thickness are important determinants of restenosis. The consistent reduction of restenosis with the thin-strut stent compared with two thick-strut stents with different architecture in both ISAR-STEREO trials strongly supports an independent role for strut thickness in restenosis. However, drug-eluting stent technology has opened new prospects for reducing restenosis and the rapamycin coated thick strut stent, the BX Velocity stent, has been shown to have very low incidence of restenosis. Future trials may be needed to answer the question whether drug eluting thin strut stents has significantly lower restenosis compared to drug eluting thick strut stents.
J Am Coll Cardiol 2003;41:1283-88.
Keywords: Risk, Follow-Up Studies, Platelet Aggregation Inhibitors, Coronary Restenosis, Coronary Angiography, Drug-Eluting Stents, Constriction, Pathologic, Sirolimus, Stents
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