Sirolimus-Eluting Stents Implanted at Coronary Bifurcation Lesions - Sirolimus-Eluting Stents Implanted at Coronary Bifurcation Lesions

Description:

The goal of the study was to evaluate the safety and efficacy of sirolimus-eluting stents for treatment of coronary bifurcation lesions.

Study Design

Study Design:

Patients Enrolled: 85
Mean Follow Up: Six months
Mean Patient Age: Mean age 63 years
Female: 20
Mean Ejection Fraction: Baseline EF 59% in each group

Patient Populations:

Age ≥18 years with diagnosis of stable or unstable angina (Braunwald classification B and C, I–II) or silent ischemia and presence of a de novo, true coronary bifurcation lesion, defined as stenosis >50% in both the main branch (MB) and ostium of the side branch (SB). Both branches needed to have at least TIMI 1 flow, a reference vessel size 2.5-3.5 mm in diameter, and a maximum treatable length ≤24 mm by visual estimation.

Exclusions:

MI in the 24 hours preceding treatment, stenosis of the left main coronary artery unprotected by a graft, angiographically visible thrombus within the target lesion, left ventricular ejection fraction (EF) ≤35%, serum creatinine ≥3.0 mg/dl, or suspected intolerance to one of the study drugs

Primary Endpoints:

Binary in-segment restenosis of both the MB and SB (stented or not stented) evaluated at the follow-up angiogram

Drug/Procedures Used:

Patients were randomized to either stenting of both branches (stent/stent; n=43) or stenting of the main branch (MB), with provisional stenting of the side branch (SB) (stent/PTCA; n=43). Patients underwent angiographic follow-up at six months. Patients were analyzed by actual treatment received, not by intention to treat.

Concomitant Medications:

Aspirin 325 mg 12 hours before the procedure and a 300 mg loading dose of clopidogrel before the procedure.

During the procedure, intravenous heparin was administered to maintain an activated clotting time >250 seconds, and glycoprotein IIb/IIIa inhibitors were used at the operator’s discretion.

Aspirin was continued indefinitely, and clopidogrel (75 mg/d) or ticlopidine (250 mg twice a day) was continued for three months.

Principal Findings:

Data were analyzed by actual treatment received, not by intention to treat. Crossover was very high: 22 patients crossed over from stent/PTCA to stent/stent (51.2%), and two patients crossed over from stent/stent to stent/PTCA (4.7%) groups.

Lesion angiographic success was ascertained in 59 cases in the stent/stent group (93.6%) and 17 cases in the stent/PTCA group (77.3%). Restenosis at six-month angiographic follow-up did not differ significantly between the stent/stent (28.0%) and the stent/PTCA (18.7%) groups (p=NS). In-stent late luminal loss trended larger in the stent/stent group versus the stent/PTCA group for the MB (0.28 mm vs. 0.14 mm, p=0.19), but did not differ for the SB (0.50 mm vs. 0.37 mm, p=0.41).

During the six-month follow-up, there was one death in the stent/stent group and none in the stent/PTCA group. There was no significant difference between groups in Q-wave myocardial infarction (MI) (1.6% vs. 4.5%), non-Q-wave MI (9.5% vs. 4.5%), target vessel revascularization with PTCA (11.1% vs. 9.0%), or target vessel failure (19.0% vs. 13.6%). There were three cases of stent thrombosis, all of which were in the stent/stent group (4.8%, 3/63).

Interpretation:

Among patients undergoing treatment of coronary bifurcation lesions, stenting of both branches using sirolimus-eluting stents was not associated with a difference in the primary endpoint of in-segment restenosis at six-month angiographic follow-up compared with stenting of the main branch, with provisional stenting of the sidebranch. Additionally, use of a stent/stent approach was associated with a relatively high stent thrombosis rate (4.8%), which is higher than rates of stent thrombosis in other trials of sirolimus-eluting stents in less complex lesions. The authors note that if the sudden death and stent thrombosis events are combined to evaluate thrombotic events, the event rate was 6.3% in the stent/stent group.

The study had several limitations. The crossover rate was high (>50%), there was not a bare stent comparison arm, the study was not blinded, and the data were analyzed by treatment received rather than intent-to-treat.

References:

Colombo A, Moses JW, Morice MC, et al. Randomized Study to Evaluate Sirolimus-Eluting Stents Implanted at Coronary Bifurcation Lesions. Circulation 2004;109

Clinical Topics: Acute Coronary Syndromes, Invasive Cardiovascular Angiography and Intervention, Stable Ischemic Heart Disease, Interventions and ACS, Chronic Angina

Keywords: Acute Coronary Syndrome, Myocardial Infarction, Follow-Up Studies, Angina, Stable, Sirolimus, Percutaneous Coronary Intervention, Stents, Body Mass Index, Coronary Stenosis, Thrombosis, Polymers, Diabetes Mellitus


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