Risk estimates for clinical outcomes following PCI vs CABG

Safety and Efficacy of PCI with DES vs CABG for Unprotected Left Main Coronary Artery Stenosis

April 18, 2017

Key Takeaways

  • There are conflicting data regarding the benefit of percutaneous coronary intervention (PCI) with drug-eluting stents (DES) vs coronary artery bypass grafting (CABG) in patients with significant unprotected left main coronary artery (ULMCA) stenosis.
  • According to this meta-analysis, CABG provided a greater efficacy profile than PCI with DES, yet there was no significant difference between CABG and PCI in terms of the primary safety endpoint.

Patients with significant unprotected left main coronary artery (ULMCA) stenosis typically undergo some type of revascularization, yet there is continuous debate as to the most appropriate, safe, and effective strategy for this patient population. The use of drug-eluting stents (DES) following percutaneous coronary intervention (PCI) has resulted in lower rates of repeat revascularization among patients with ULMCA stenosis, suggesting that PCI with DES may be the most optimal revascularization strategy. Nevertheless, there are few studies comparing PCI and DES with coronary artery bypass grafting (CABG) in regard to effectiveness and safety in ULMCA stenosis patients.

A meta-analysis by Nerlekar N et al reviewed randomized trials comparing PCI with DES and CABG, specifically examining safety and effectiveness outcomes.1 After evaluating nearly 4000 studies, researchers identified 5 randomized trials that fit their prespecified inclusion criteria. The inclusion criteria were as follows:

  • Must be a fully published randomized controlled trial (RCT)
  • RCT must have been involved in studying the left main coronary artery
  • The study must have compared clinical outcomes between CABG and PCI using DES

Overall, a total of 4594 patients with a subset group of 2297 undergoing PCI with DES were included in this analysis. Clinical safety, as defined as the composite of all-cause death, myocardial infarction (MI), or stroke, comprised the primary endpoint.

Figure 1.Risk estimates for clinical outcomes following PCI vs CABGa
Risk estimates for clinical outcomes following PCI vs CABG
aData from Nerlekar N, Ha FJ, Verma KP, et al1

There were no differences between the revascularization strategies as they relate to all-cause mortality or MI incidence. There were significantly fewer events of repeat revascularization with CABG vs PCI (8.3% vs 14.2%). In regard to the secondary effectiveness endpoint, there was little difference between PCI and CABG at 1 year; however, PCI correlated with a greater risk of adverse events.

Researchers hypothesize that intravascular ultrasound (IVUS), used frequently during PCI in the PRECOMBAT trial, may have contributed to the reduced risk for reintervention. Previously reported effectiveness of IVUS-guided PCI in reducing repeat revascularization as well as the ability of IVUS to provide extensive evaluation of lesion severity and quantification of vessel dimensions, thus improving the chance of choosing the most appropriate treatment strategy, may explain the benefit of using IVUS prior to therapy.2

While the pooled analysis observed no significant difference between PCI with DES and CABG in low surgical risk patients, the authors suggest CABG may hold greater benefit as it was consistently associated with a lower rate of repeat revascularization in patients with ULMCA stenosis.


  1. Nerlekar N, Ha FJ, Verma KP, et al. Percutaneous Coronary Intervention Using Drug-Eluting Stents Versus Coronary Artery Bypass Grafting for Unprotected Left Main Coronary Artery Stenosis: A Meta-Analysis of Randomized Trials. Circ Cardiovasc Interv. 2016;9(12).
  2. Hong SJ, Kim BK, Shin DH, et al. Effect of Intravascular Ultrasound-Guided vs Angiography-Guided Everolimus-Eluting Stent Implantation: The IVUS-XPL Randomized Clinical Trial. JAMA. 2015;314(20):2155-2163.


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