Prospective Randomized Trial of Sirolimus-Eluting and Bare Metal Stents in Patients With Chronic Total Occlusions - PRISON II

Description:

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.

Study Design

Study Design:

Patients Enrolled: 200
Mean Follow Up: Six months
Mean Patient Age: Mean age 59 years
Female: 20

Patient Populations:

Chronic total occlusion >2 weeks old and signs of ischemia related to the target vessel

Exclusions:

Lesion that could not be crossed; unable to take aspirin, heparin, or clopidogrel; or severe renal failure

Primary Endpoints:

Angiographic binary restenosis at six months

Secondary Endpoints:

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)

Drug/Procedures Used:

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).

Concomitant Medications:

Aspirin (100 mg) and clopidogrel (75 mg) for ≥6 months

Principal Findings:

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.

Interpretation:

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.

References:

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.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Stable Ischemic Heart Disease, Chronic Angina

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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