Unprotected Left Main Stem PCI with Drug Eluting Stents is Associated with Favorable Long-term Outcomes

June 3, 2008 By Vijayalakshmi Kunadian MBBS MD MRCP [mailto:vkunadian@perfuse.org]

JACC: Percutaneous coronary intervention using drug eluting stents for unprotected left main stem stenosis demonstrates favorable long-term (3 years) outcomes in a new study among elective and emergency cases.

Among patients with significant left main stem stenosis, coronary artery bypass surgery is still the favored method of revascularization. However, previous observational studies suggest favorable outcomes with percutaneous intervention using drug eluting stents (DES). But the use of DES however is associated with an increase in late stent thrombosis.

In a recent publication in JACC, Meliga and colleagues determine the long term (3 years) clinical outcomes with left main PCI using DES. Their study is an international, multicenter, retrospective registry design consisting of real world population recruited between April 2002 and April 2004 from Europe and United States. 358 patients underwent PCI with sirolimus eluting and paclitaxel eluting stents for de novo lesions located in the ostium, shaft and distal segments of the unprotected left main stem. Patients with EuroSCORE >6 were considered high risk and >9 were considered very high risk.

The mean age of study patients was 66.1±11.2 and 30.2% of patients had diabetes mellitus (IDDM 16.2%, NIDDM 14%), 18.9% had prior coronary artery bypass surgery, the mean left ventricular ejection fraction was 48.6±12.8% and the mean EuroSCORE was 6.4±4.1. The most common admission diagnosis was stable angina (44.1%), unstable angina (41.9%), acute myocardial infarction (8.4%), cardiogenic shock (2.8%) and silent ischemia (2.8%).

19.6% of cases underwent emergent PCI. The lesion was located in the ostium/shaft in 26.3% of cases and the remaining lesions were located in the distal segment of the left main stem. Multiple stents were used in 43.3% of cases. Cypher and Taxus stents were used in almost equal proportions (54.5% and 45.5%). Provisional stenting was adopted in majority of the cases (56.7%) and crush stenting was used in 26.5% of cases. Intra-aortic balloon pump was used in 13.9% of cases.

Technical procedural success was achieved in all patients (100%). The overall in-hospital major adverse cardiac event (MACE-cardiac death, nonfatal myocardial infarction, or target vessel revascularization) rate was 11.1%, which occurred more frequently following emergency PCI than elective PCI (22.8% vs. 8.3%, p<0.001). Likewise the in-hospital cardiac death was more frequent in the emergency cases (12.8% vs. 0.7%, p<0.001). At one year, the overall MACE rate was 24.3% (elective: 22.2% vs. emergency: 32.9%, p=0.046). The difference in MACE at one year between elective and emergent cases was attributed to an increase in cardiac death in the emergency group (18.6% vs. 3.8%, p<0.001). At 3 years, the overall MACE rate was 32.1%, with no difference in MACE between elective and emergency cases (p=0.126). However, at 3 years, the elective group underwent more target vessel revascularization compared with the emergency group (16% vs. 7.1%, p=0.037). Beyond 3 years, the overall incidence of cardiac death was 10.6% (elective: 6.9% vs. emergency 25.7%, p<0.001) and the overall MACE rate was 34.9% (elective: 31.6% vs. emergency: 48.5%, p=0.006). In total, stent thrombosis according to the ARC definition occurred in 6.1% of cases (acute 0.6%, subacute 0.6%, late 2.2% and very late stent thrombosis in 10 cases).

In a multivariate analysis, age [HR 1.06 (95% CI 1.01 to 1.11, p=0.010)], shock [HR 11.0 (1.88 to 63.9), p=0.008], and EuroSCORE [HR 1.15 (1.01 to 1.31), p=0.046] were identified as independent predictors of cardiac death. The IDDM [HR 2.85 (1.29 to 6.17), p=0.009] and EuroSCORE [HR 1.10 (1.02 to 1.19), p=0.014] were predictors of MACE whereas, impaired ejection fraction [HR 1.03 (1.01 to 1.05), p=0.050], IDDM [HR 2.92 (1.60 to 5.30), p<0.001] and multiple stenting [HR 4.51 (1.07 to 19.0), p=0.040] were independent predictors of the need for target vessel revascularization.

The investigators concluded that PCI to unprotected left main stem using DES is associated with “a satisfactory rate in both single and composite outcomes”. Beneficial effects were more frequently observed in elective population compared with the emergency cases over a 3 year period with lower rates of stent thrombosis.

Source

 * 1) http://content.onlinejacc.org/cgi/content/abstract/51/23/2212.