Prospective Randomized Trial of Sirolimus-Eluting and Bare Metal Stents in Patients With Chronic Total Occlusions - PRISON II
The goal of the trial was to evaluate treatment with bare metal stents or sirolimus-eluting stents among patients with chronic total occlusions in native coronary arteries.
Patients Enrolled: 200
Mean Follow Up: Six months
Mean Patient Age: Mean age 59 years
Chronic total occlusion >2 weeks old and signs of ischemia related to the target vessel
Lesion that could not be crossed; unable to take aspirin, heparin, or clopidogrel; or severe renal failure
Angiographic binary restenosis at six months
MACE at six months, defined as cardiac death, MI, and ischemia-driven target lesion revascularization; target vessel failure at six months, defined as cardiac death, MI, and ischemia-driven target vessel revascularization; and angiographic parameters at six-month follow-up (minimum lumen diameter, percent diameter stenosis, late lumen loss)
After crossing the lesion, patients at two clinical centers were randomized to either bare metal stenting with the BX Velocity stent (n=100) or treatment with the sirolimus-eluting Cypher stent (n=100).
Aspirin (100 mg) and clopidogrel (75 mg) for ≥6 months
Baseline characteristics were well balanced between treatment groups, with 13% diabetics, single-vessel disease in 49% of patients, and right coronary artery intervention in 42%. An average of 1.4 stents were used per patient in both groups, with a mean occlusion length of 16 mm. Preintervention TIMI flow grade 0 was present in 66% of patients. The duration of occlusion was longer than three months in 45% of patients.
The primary endpoint of binary angiographic restenosis occurred less often in the sirolimus-eluting stent group than the bare metal stent group (in-segment 11% vs. 41% p<0.0001; in-stent 7% vs. 36%, p<0.001). Other angiographic parameters were also improved in the sirolimus-eluting stent group compared with the bare metal stent group, including in-segment minimum lumen diameter (2.09 mm vs. 1.32 mm, p<0.001), late lumen loss (-0.07 mm vs. 0.64 mm, p<0.001), and percent diameter stenosis (31.9% vs. 53.3%, p<0.001).
Major adverse cardiac events (MACE) at six months occurred less frequently in the sirolimus-eluting stent group (4% vs. 20%, p<0.001), driven almost exclusively by a reduction in target lesion revascularization (4% vs. 19%, p=0.001) with no difference in myocardial infarction (MI) (2% vs. 3%) and no deaths in the trial. Similar results were seen for target vessel revascularization (8% vs. 22%, p=0.009). There were two cases of stent thrombosis in the sirolimus-eluting stent group and none in the bare metal stent group.
Among patients with chronic total occlusions in native coronary arteries, treatment with sirolimus-eluting stents was associated with a reduction in binary angiographic restenosis at six-month follow-up compared with treatment with bare metal stents.
The PRISON I trial demonstrated a reduction in target lesion revascularization among chronic total occlusions treated with bare metal stenting compared with balloon angioplasty. While registry data have reported on the use of drug-eluting stents in chronic total occlusions, the present study is the first randomized trial to compare the efficacy of sirolimus-eluting stents with bare metal stents in this population, which has traditionally been excluded from the larger randomized studies of drug-eluting stents.
The angiographic efficacy was consistent in the present trial. However, there were two cases of stent thrombosis among the 100 patients treated with a sirolimus-eluting stent (2%), a rate higher than often seen in trials with lower risk populations. Data on stent thrombosis with drug-eluting stents must be closely monitored, given the lack of available trial data in these higher risk populations.
Suttorp MJ, et al. Primary Stenting of Totally Occluded Native Coronary Arteries II (PRISON II). Circulation 2006;114 921-928.
Presented by Dr. Maarten J. Suttorp at TCT 2005, Washington, DC.
Keywords: Myocardial Infarction, Follow-Up Studies, Coronary Restenosis, Metals, Thrombosis, Drug-Eluting Stents, Constriction, Pathologic, Coronary Vessels, Sirolimus, Angioplasty, Balloon, Coronary, Diabetes Mellitus
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