Intracoronary Stenting and Angiographic Results: Drug-Eluting Stents for Unprotected Coronary Left Main Lesions - ISAR-LEFT MAIN

Description:

Recent literature suggests that drug-eluting stents are superior to bare-metal stents in patients undergoing unprotected left main (LM) stenting. The current trial sought to compare sirolimus-eluting (SES) and paclitaxel-eluting stents (PES) in patients undergoing unprotected LM stenting.

Hypothesis:

PES would be noninferior to SES in patients undergoing unprotected LM stenting.

Study Design

Study Design:

Patients Screened: 694
Patients Enrolled: 607
Mean Follow Up: 1 year
Mean Patient Age: 69 years
Female: 23
Mean Ejection Fraction: 54%

Patient Populations:

Patients with ischemic symptoms or evidence of myocardial ischemia in the presence of ≥50% stenosis located in unprotected LM lesions

Exclusions:

  • Age <18 years
  • Cardiogenic shock
  • ST-elevation acute MI within 48 hours of symptom onset
  • In-stent restenosis
  • Prior coronary artery bypass surgery
  • LM size >4.5 mm by visual estimation
  • Malignancies with life expectancy <1 year
  • Planned staged percutaneous coronary intervention (PCI) within 30 days from index PCI
  • Planned elective surgical procedure necessitating discontinuation of clopidogrel during the first 6 months
  • Pregnancy

Primary Endpoints:

Incidence of MACE, defined as death, MI, or need for target lesion revascularization at 1 year

Secondary Endpoints:

Angiographic restenosis at 6- and 9-month follow-up angiogram

Drug/Procedures Used:

LM stenting with either PES or SES. Use of two stents in “culotte” with final kissing balloon inflation was the preferred technique for distal bifurcation lesions.

Concomitant Medications:

All patients received clopidogrel 600 mg at least 2 hours before the procedure, in addition to 500 mg of intravenous aspirin. In addition, all patients received clopidogrel (150 mg/day for the first 3 days, 75 mg/day thereafter) and aspirin 200 mg/day indefinitely. Patients also received heparin and glycoprotein IIb/IIIa inhibitors (10%) or bivalirudin (15%). Other medications included statins (95%) and beta-blockers (98%).

Principal Findings:

A total of 607 patients were randomized, 302 to PES, and 305 to SES. Baseline characteristics were fairly similar between the two groups. About 29% of the patients were diabetic, 42% presented with an acute coronary syndrome, and about 73% of the patients had evidence of three-vessel disease. Trifurcation morphology was present in about 25% of the patients. The mean LM size was about 3.8 mm. The majority of LM lesions were distal (63%), whereas about 12% were ostial LM lesions. The mean EuroSCORE was 4.6.

About one-half of the patients received a single stent, whereas Culotte stenting was employed in most of the other patients; T-stenting was employed in only about 1.5% of the patients. An intra-aortic balloon pump was necessary in only 1% of the patients. Intravascular ultrasound (IVUS) was not used in this study.

The use of PES was noninferior compared with SES in the incidence of major adverse cardiac events (MACE) at 1 year (13.6% vs. 15.8%, relative risk [RR] 0.85, 95% confidence interval [CI] 0.56-1.29; p for noninferiority < 0.001). The incidence of death (5.0% vs. 6.6%), myocardial infarction (MI) (5.0% vs. 4.6%), and stroke (1.7% vs. 1.0%) at 1 year was similar between the two arms. Angiographic restenosis was similar between the two arms at 6-9 months as well (16.0% vs. 19.4%, p = 0.3).

Two-year target lesion revascularization rates were similar as well (9.2% vs. 10.7%, p = 0.47). The incidence of definite (0.3% vs. 0.7%, p = 0.57) and probable (0% vs. 0.3%, p = 0.32) stent thrombosis at 2 years was also similar between the two arms. Thirty-day outcomes were also similar between the two arms. Results for the main outcome were similar in diabetic patients.

Interpretation:

The results of this trial confirm the safety of drug-eluting stent PCI in treating unprotected LM lesions, and indicate that PES are noninferior to SES for this indication. The incidence of 2-year stent thrombosis was about 0.5-1.0% (all events occurred before 30 days), although all patients were on dual antiplatelet therapy indefinitely. Further long-term data are necessary.

References:

Mehilli J, Kastrati A, Byrne RA, et al., on behalf of the ISAR-LEFT MAIN (Intracoronary Stenting and Angiographic Results: Drug-Eluting Stents for Unprotected Coronary Left Main Lesions) Study Investigators. Paclitaxel- versus sirolimus-eluting stents for unprotected left main coronary artery disease. J Am Coll Cardiol 2009;Feb 25:[Epub ahead of print].

Presented by Dr. Julinda Mehili at the Transcatheter Cardiovascular Therapeutics meeting (TCT 2008), Washington, DC, October 2008.

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

Keywords: Paclitaxel, Risk, Myocardial Infarction, Stroke, Coronary Restenosis, Thrombosis, Drug-Eluting Stents, Constriction, Pathologic, Confidence Intervals, Sirolimus, Angioplasty, Balloon, Coronary, Diabetes Mellitus


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