The heart is a fist-sized powerhouse that pumps oxygen and nutrient-rich blood throughout the body to keep us alive. Aorta that bifurcate into two major coronary arteries – Left Main Coronary Artery (LMCA) and Right Coronary Artery (RCA) supply blood to the heart tissues keeping them nourished so that they can function perfectly. Left Coronary Artery also known as Left main stem coronary artery (LMS) branches into Left Anterior Descending Artery (LAD) and Left Circumflex Artery that supplies the left side of the heart muscles and front of the septum with blood. While the Right Coronary Artery divides into the Right Marginal Artery and Posterior Descending Artery which supplies blood to the right side of the heart and sinoatrial nodes. Hence, any blockage in the coronary arteries will disrupt or cut off the blood flow to the heart muscles (myocardium), resulting in its damage or death.
Plaque that builds up in the coronary arteries as a result of atherosclerotic condition is the major cause of restricted blood flow. Coronary arterial stenosis of greater than or equal to 50% narrowing is associated with multivessel disease and is termed as the significant left main disease (LMD). Patients with coronary heart disease often suffer from severe chest pain and discomfort as the heart becomes starved of oxygen and nutrients. In some cases, whenever there is a clogging in the right or left main coronary artery, the collateral vessels become active, and bypassing the blockage they serve as alternative conduits for blood flow. However, it is not a cure or standard medical care option to rely on the functioning of collateral arteries.
Medical therapy and surgical revascularization (Coronary Artery Bypass Graft Surgery and Percutaneous Coronary Intervention) are the main options available for treating coronary arterial stenosis. Medical therapy was not proven beneficial for treating LMD as the survival rates were far below. Performing bare-metal stenting often ended up in higher restenosis rates, acute thrombosis and repeat revascularization. Hence, Bypass surgery (CABG) turned out to be the standard of care for left main disease as it improves the likelihood of survival.
However, advancements in catheterization and medical imaging techniques such as FFR and Optical Coherence Tomography (OCT) have led to the resurgence of interest in Percutaneous coronary Intervention (PCI). Providing a detailed and clear visualization of coronary morphology, OCT has evolved as an indispensable tool for developing new types of coronary stents. Optical Coherence Tomography when used as a guide for coronary interventions ensures better outcomes. Even though, CABG remains to be the superior choice for treating left main CAD, cardiologists hope that the ongoing studies and trials may bring more light into the role of percutaneous approach in near future.
