| MEDICAL ANIMATION TRANSCRIPT: The right and left coronary arteries arise from the aorta and supply the heart with blood, nutrients and oxygen. Coronary artery disease, also known as CAD, is a condition in which one or both coronary arteries can no longer deliver sufficient blood and oxygen to the heart muscle. In the bloodstream, cholesterol, a lipid synthesized in the liver and obtained from the diet, and fatty acid compounds, such as triglycerides, bind to either low-density lipoprotein, called LDL, or high-density lipoprotein, called HDL, and circulate throughout the body. When the endothelial lining of the coronary arteries becomes damaged, LDL-bound cholesterol and triglycerides adhere to the artery wall. The build up of LDL, also known as bad cholesterol, and triglycerides inside the artery wall forms a lesion called a fatty streak and triggers an immune response. Monocytes enter the lesion and transform into macrophages. These cells digest cholesterol and become foam cells, forming an atheroma, or plaque, with a lipid core. This inflammatory process involving fatty plaque accumulation and abnormal cellular changes in artery walls is called atherosclerosis and is a major cause of CAD. Over time, an advanced atherosclerotic plaque may weaken and rupture. In an inflammatory response, platelets and arthryocytes form a blood clot called a thrombus, occluding the artery. Insufficient blood flow, called ischemia, occurs and may eventually lead to tissue death, known as infarction. Treatment for CAD can involve lipid-lowering medications, such as HMG-CoA reductase inhibitors, or statins, which inhibit cholesterol synthesis in the liver and help remove LDL cholesterol from the bloodstream. Aspirin and other antiplatelet medications prevent thrombis formation by reducing platelet aggregation. Beta blocker medications slow down the heart rate, improving blood and oxygen supply to the myocardium. Angioplasty is also known as percutaneous transluminal coronary angioplasty, or PTCA, percutaneous coronary intervention, or PCI, or balloon angioplasty. During the procedure, the physician threads a guide wire into the femoral artery and into the aorta. The physician passes a catheter with a small balloon into the narrowed coronary artery lumen. When the balloon is inflated, then deflated, it flattens the plaque against the artery wall, opening the lumen. In some cases, a wire mesh tube called an endovascular stent may be placed over the balloon and then expanded inside the artery to maintain the open lumen. ♪ [music] ♪ |
