Complications of Atherosclerosis

An atheroma (atheromatous plaque) grows slowly and narrows the lumen of an artery. Therefore, it reduces the blood flow in the affected artery gradually. A 50 % reduction in diameter of the lumen causes a 70 % reduction in the cross-sectional area. It leads to a significant obstruction in the particular artery. Clinical presentations of its complications can vary according to the site of atherosclerosis.


Coronary artery disease (ischaemic heart disease)

If a main coronary artery or its branch has a significant obstruction due to atherosclerosis, any increase in oxygen and nutrient demand of the myocardium triggers ischaemia. This clinical presentation is known as stable angina. Usually, a person with stable angina will not feel any ischaemic symptom at rest.

Sometimes, an atheroma, which is in a coronary artery, can be complicated with formation of a blood clot (thrombus) over or in the plaque. A thrombus may obstruct the blood flow partially or completely. These clinical presentations are known as acute coronary syndromes.

Partial occlusion of the blood flow causes significant ischaemia, which leads to a disease called unstable angina. An individual with unstable angina gets ischaemic chest pain even at rest. Usually, ischaemia won’t cause death of the affected myocardium. However, total occlusion of the blood supply can lead to death of the affected myocardium (infarction). This is referred to as myocardial infarction or MI.


Stroke or transient ischaemic attack (TIA)

Atherosclerosis can narrow main arteries of the brain, including carotid arteries. It can lead to a stroke or a TIA.


Aneurysms

Atherosclerosis may weaken the arterial wall and form a bulge (aneurysm). If an aneurysm of the aorta (aortic aneurysm) ruptures, a life-threatening bleeding may occur.


Thromboembolism

A blood clot (thrombus) over an atheromatous plaque or aneurysm may dislodge and travel via blood (embolism). Then, it can block a distant artery. This process may lead to a stroke or a TIA.


Peripheral vascular disease (PVD)

Atherosclerosis can narrow the arteries in the upper and lower limbs. It causes sensory impairment, raising the risk of injuries and burns. Sometimes, PVD can lead to gangrene (tissue death) in the limbs. Depending on the severity of gangrene, PVD may result in amputation of a part of the affected limb.



Related Links:

What Is Ischaemic Heart Disease?
Process of Atherosclerosis and Thrombosis
Introduction: Risk Factors of Atherosclerosis
Non-modifiable Risk Factors of CAD
Modifiable Risk Factors of CAD
Other Risk Factors of CAD
Cardiovascular Disease (CVD) Prevention Policy