Left Main Disease: The Last Frontier for Medical Therapy in Stable Coronary Artery Disease?

Patients with stable coronary artery disease (CAD) involving ≥50% stenosis in the left main coronary artery almost invariably undergo revascularisation. However, there is lack of evidence from contemporary randomised controlled clinical trials (RCTs) supporting the superiority of this approach versus an initial strategy of intensive, multifaceted optimal medical therapy (OMT) directed at dyslipidaemic, hypertensive, thrombotic, metabolic and ischaemic targets. Current clinical practice guidelines still base their recommendations on small subsets of RCTs conducted in the 1970s and early 1980s. Given the lack of survival benefit among patients with stable, multi-vessel coronary artery disease who do versus those do not undergo routine revascularisation in the era of advanced OMT, the question arises whether the current treatment recommendations for left main disease are valid. This issue is of considerable importance; while significant left main disease is found in only 8-10% of diagnostic invasive angiography cases, it is a disease entity associated with a high risk of adverse clinical events and extensive resource use. This article discusses clinical trials data as well as challenges to address this question in the contemporary era. It highlights the complexities of trial planning and execution as it relates to both feasibility and equipoise, study design, choice of trial endpoints and duration of follow-up. The authors conclude there is a compelling need for an RCT to test the hypothesis that the current practice of routine revascularisation for all patients with LMD is superior to an initial strategy of multifaceted OMT with selective use of revascularisation.