Blood is essential to life, delivering oxygen, nutrients, hormones, and immune cells to every tissue in the body. This blood must reach them efficiently and continuously for our organs and muscles to function properly. To know how our bodies do this, it is important to understand the structure and function of the heart, a powerful muscular pump at the center of a complex plumbing system made up of arteries and veins. Blood flow in the heart begins with deoxygenated blood returning from the body through the superior and inferior vena cava into the right atrium. It then moves into the right ventricle and is pumped out through the pulmonary trunk to the lungs, via the pulmonary arteries, where it receives a fresh supply of oxygen. The oxygen-rich blood returns to the heart’s left atrium, via the pulmonary veins and then enters the left ventricle. The powerful muscles of the left ventricle can push oxygenated blood out through the aorta to circulate throughout the body. This system must operate smoothly to sustain life, and any disruption in the body’s circulatory plumbing system, especially within the heart, can lead to serious problems. One of those disruptions is coronary artery disease, caused by arteriosclerosis in the heart.

     Arteriosclerosis is when the arteries lose their natural flexibility, or compliance, becoming thickened and stiff (Betts, et al., 2022). This reduced compliance makes it harder for the vessels to expand and recoil with each heartbeat, increasing resistance and forcing the heart to work harder to maintain blood flow, often leading to elevated blood pressure. Arteriosclerosis begins with injury to the artery’s inner lining, the endothelium, which can result from factors such as hypertension, diabetes, elevated triglycerides, and advanced age (Agha, Yacoub, Zahergivar, & Pepe, 2020). The body responds to this injury with inflammation, which weakens and scars the vessel wall. Over time, cholesterol, triglycerides, white blood cells, calcium, and cellular debris accumulate at the injury site, forming plaque in a process known as atherosclerosis (Betts, et al., 2022). When this process explicitly affects the coronary arteries, the vessels responsible for delivering oxygen-rich blood to the heart muscle, it’s called coronary artery disease (CAD).

     The coronary arteries are the vessels that supply oxygen-rich blood from the heart to the rest of the body, ensuring it has the energy and nutrients needed to keep pumping. The left coronary artery serves the left side of the heart, including the left atrium, left ventricle, and most of the interventricular septum. The right coronary artery mainly supplies the right side of the heart, including the right atrium, right ventricle, and parts of the heart’s electrical conduction system. Both arteries branch out across the surface of the heart and send smaller vessels deep into the muscle tissue. Although small interconnections called anastomoses exist between branches, they are usually not large enough to fully compensate if one artery becomes blocked, making the coronary arteries vital to the heart’s survival and function (Libby & Theroux, 2005).

     CAD typically presents in two primary forms: stable ischemic heart disease and acute coronary syndrome (ACS). In stable ischemic heart disease, plaque buildup within the coronary arteries gradually narrows the vessels over time, limiting blood flow to the heart muscle during periods of increased demand, such as during exercise or stress (Betts, et al., 2022). This typically causes predictable chest pain or discomfort known as stable angina, which resolves with rest or medication (Libby & Theroux, 2005). In contrast, ACS refers to a sudden and more severe reduction in blood flow, often due to the rupture of a plaque and formation of a blood clot that partially or completely blocks a coronary artery. ACS includes severe conditions like unstable angina, non-ST elevation myocardial infarction (NSTEMI), and ST elevation myocardial infarction (STEMI), all of which are medical emergencies (Libby & Theroux, 2005). ST elevation, or ST segment, refers to the specific portion of the heart’s electrical activity as seen on an electrocardiogram, ECG or EKG (Betts, et al., 2022). While stable ischemic disease tends to be chronic and manageable, acute coronary syndrome poses an immediate threat to heart tissue and requires urgent intervention.

     Treatment and prevention of coronary artery disease (CAD) focus on reducing risk factors, improving blood flow, and protecting heart tissue. Preventive strategies are centered on lifestyle modifications such as maintaining a heart-healthy diet, engaging in regular physical activity, quitting smoking, managing stress, and controlling conditions like high blood pressure, diabetes, and high cholesterol (Libby & Theroux, 2005) (Giraudo, et al., 2025). Medical treatment may include medications such as statins to lower cholesterol, antihypertensives to reduce blood pressure, antiplatelet agents like aspirin to prevent clot formation, and beta-blockers or nitrates to decrease the heart’s workload and relieve symptoms (Betts, et al., 2022) (Libby & Theroux, 2005). In more advanced cases, procedures like angioplasty with stent placement or coronary artery bypass grafting (CABG) may be necessary to restore proper blood flow to the heart (Betts, et al., 2022). Early intervention and consistent management are key to slowing disease progression, reducing complications, and improving quality of life.

References

Agha, A. M., Yacoub, B., Zahergivar, A., & Pepe, J. (2020, January 29). Marijuana use and coronary artery disease in young adults. PLOS One. doi:https://doi.org/10.1371/journal.pone.0228326

Betts, J. G., Young, K. A., Wise, J. A., Johnson, E., Poe, B., Kruse, D. H., . . . DeSaix, P. (2022). Anatomy and Physiology 2e. Houston, Texas: OpenStax. Retrieved from https://openstax.org/books/anatomy-and-physiology-2e

Giraudo, M. T., Milani, L., Padroni, L., Sieri, S., Agnoli, C., Simeon, V., . . . Sacerdote, C. (2025). Increased risk of coronary artery diseases in overweight and obese individuals is partially mediated by chronic inflammation: The EPICOR study. Nutrition, Metabolism and Cardiovascular Diseases, 35(4). Retrieved from https://doi.org/10.1016/j.numecd.2024.103831.

Libby, P., & Theroux, P. (2005). Pathophysiology of Coronary Artery Disease. American Heart Association Journals, 111(25). doi:doi:10.1161/CIRCULATIONAHA.105.537878