Left Main Coronary Artery Percutaneous Coronary Intervention in High-Risk Patients: Hopes for Improvement and Limitations of Randomized Trials

Abstract

Obstructive coronary artery disease involving the left main coronary artery (LMCA) is found during cardiac catheterization in 4%-6% of patients. Randomized trials performed in the 1970s included small subgroups of patients with unprotected LMCA (ULMCA) and demonstrated the superiority of coronary artery bypass grafting (CABG) compared with medical management, which led to recommending CABG for those patients. Although technically, LMCA percutaneous coronary intervention (PCI) is often feasible, the outcome with balloon angioplasty or bare metal stenting was initially disappointing. In fact, the first patient who underwent PCI to the LMCA by Andreas Gruentzig in 1978, died within a year. CABG remained the preferred approach for this subset of patients. Advances in the realm of interventional cardiology, including the advent of the drugeluting stent (DES), have made the treatment of ULMCA disease with PCI a more acceptable treatment as an alternative to CABG. There is a growing body of evidence to support the treatment of ULMCA disease with PCI as opposed to CABG. However, because of the common assumption that withholding surgery is unethical, patients have usually been excluded from randomized clinical trials (RCTs) comparing PCI and CABG. Only a few RCTs to date have compared the efficacy of CABG and PCI in this setting, and even then most did not specifically target this population but reported subgroup results. The Synergy Between Percutaneous Coronary Intervention with TAXus and Cardiac Surgery (SYNTAX) trial randomized 1800 patients with 3-vessel or ULMCA disease, or both, to CABG or PCI using a first-generation DES. Among the 750 patients in the ULMCA disease subgroup, 1-year major adverse cardiovascular and cerebrovascular event (MACCE) rates were similar for PCI and CABG