Cardiovascular Disease

The main function of the cardiovascular system is to transport blood throughout the body. Cardiovascular disease (CVD) occurs when blood flow becomes obstructed. Atherosclerosis, a build-up of deposits on the inside of arteries, is a primary cause.

Blocked Coronary Artery

Atherosclerosis is a gradual disease process. Normal, healthy arteries start out smooth and stretchy. During early adulthood, fatty particles from the blood make their way into the inner layer of the artery. They build up and form fatty streaks. Injuries to the internal lining from smoking, high blood pressure, or diabetes, make it more likely that fatty particles will build up.

As time goes on, fat from low-density lipoproteins (LDLs) continues to build up. The lipids react with oxygen and are taken up by smooth muscle cells of the artery. The cells develop a foamy appearance. The foam cells attract platelets from the blood stream as well as calcium deposits and cell debris. The wall of the artery becomes inflamed as white blood cells try to heal the injured area. In the meantime, a fiber-like cap forms over the fatty mixture and creates a hardened lesion called an atherosclerotic plaque. As the plaque continues to grow, it stiffins and narrows the affected artery and slows the flow of blood through it.

Atherosclerosis

At times, the fibrous caps covering atherosclerotic plaques may rupture. When this occurs, blood cells called platelets are exposed to the contents of the plaque. This causes them to collect and form a clot at the site of the rupture—a process called thrombosis. Sometimes, these clots can grow large, leading to the total obstruction of flow in the artery. Pieces of the clot, called emboli, may also break off and travel downstream and block other arteries.

Blood Clot Blocking Blood Flow

Atherosclerosis can eventually lead to the following conditions:

—A stroke occurs when brain cells die because they are not getting enough oxygen via the bloodstream. 80% of strokes are caused by blockage of an artery leading to the brain.
(CAD)
- Angina —Narrowing of the coronary arteries, which carry blood to the heart muscle, may create a supply and demand problem for the heart. Myocardial ischemia results when demand for oxygen is greater than its supply. This often occurs at times of exertion or stress. Most patients experience myocardial ischemia as chest pain, also known as angina.
- Heart attack—Heart attack refers to the death of heart cells due to lack of oxygen. Most heart attacks occur when a large clot forms in a coronary artery, cutting off the flow of blood to the heart. Complications include heart failure and cardiac arrhythmias, which result from the abnormal conduction of electrical signals through heart tissue.
- Heart failure (HF)—HF occurs when the heart is unable to pump enough blood to the body. It is usually the result of a heart that has weakened over time, often because of long-standing coronary heart disease, high blood pressure, or both. Other causes include myocardial infarction or abnormalities of the heart valves.
(PAD)—PAD refers to the narrowing of arteries that carry blood to the extremities, most commonly in the legs. People with severe arterial narrowing often have pain and fatigue when they walk. An aneurysm or bulge in an artery may also occur due to its weakened wall. Aneurysms can occur anywhere, but when associated with atherosclerosis, they most commonly occur in the abdominal portion of the aorta.

Other cardiovascular conditions unrelated to atherosclerosis include:

Congenital defects of the valves, chambers, and great vessels
Some types of irregular heartbeats— arrhythmias
Inflammation or infections of the heart muscle ( myocarditis), valves, or pericardial sac that surrounds the heart ( pericarditis)
Cardiac tumors
Venous conditions, such as varicose veins, thrombophlebitis, and deep venous thrombosis (DVT)

References

Coronary artery disease (CAD). EBSCO DynaMed website. Available at: http://www.dynamed.com/topics/dmp~AN~T116156/Coronary-artery-disease-CAD. Accessed January 29, 2021.
Heart failure with reduced ejection fraction. EBSCO DynaMed website. Available at: http://www.dynamed.com/topics/dmp~AN~T114099/Heart-failure-with-reduced-ejection-fraction. Accessed January 29, 2021.
Atherosclerosis. Merck Manual Professional Version website. Available at: http://www.merckmanuals.com/professional/cardiovascular-disorders/arteriosclerosis/atherosclerosis. Accessed January 29, 2021.