Clogged blood vessels

Blood vessels consists of arteries, veins and capillaries. Arteries carry oxygen-rich blood from the heart to all body tissues. Veins carry oxygen-poor blood back to the heart. Capillaries are small, thin blood vessels that connect the arteries and the veins. 

Healthy blood vessels have smooth inner walls and blood flows through them easily. Aging and unhealthy lifestyles cause some people to develop clogged arteries. Clogged arteries result from a build-up of plaque on the inner walls of the arteries, a condition known as atherosclerosis. Plaque is a waxy, sticky deposit made up of cholesterol, fat, calcium and fibrin (protein involved in blood clotting). As the plaque builds up, the walls of the arteries thicken, lose their elasticity and become narrower, restricting the blood flow. The plaque can burst, triggering a blood clot (thrombus) to form around the plaque. A clot may either further narrow the artery or completely block it. 

Clogged arteries could lead to a heart attack, stroke and even sudden death. The narrowing of coronary arteries decreases the blood flow to the heart, leading to chest pain (angina), shortness of breath, heart palpitations and weakness. A heart attack happens when blood flow to a part of the heart is blocked. Similarly, stroke happens when blood vessel feeding the brain is blocked. If the veins carry blood from the lower body back to the heart is blocked, this would lead to acute pain, swelling or warmth in the affected leg, a condition known as deep vein thrombosis (DVT).

Your risk of stroke

Risk factors of clogged blood vessels

Clog can happen in the arteries, as well as in the veins.  Many risk factors for clogged arteries and clogged veins are the same. Risk factors for clogged arteries includes:

  • Ageing
  • Obesity
  • Sedentary lifestyle
  • Lack of movement, such as on a long trip
  • Smoking
  • Diabetes
  • High cholesterol
  • High blood pressure
  • Family history
  • Poor diet, such as high amounts of saturated fat, trans fat, salt and sugar

Risk factors for clogged veins includes:

  • Ageing
  • Obesity
  • Lack of movement, such as on a long trip
  • Smoking
  • Pregnancy
  • Hormone therapy or birth control pills
  • A history of DVT
  • Family history of DVT
  • Inherited blood clotting disorders
  • Injury to vein, such as from surgery or broken bone

How to test for clogged blood vessels

In most cases, clogged arteries do not cause any symptoms until a major event, such as chest pain, heart attack, stroke or sudden cardiac arrest happens. Nonetheless, there are several tests available to test for clogged blood vessels. Doctor will determine which test to use depending on your symptoms and medical history:

Chest X-ray

to visualise condition of the lungs, such as if blood vessels in the lungs are abnormal or if there is fluid in or around the lungs


to check the blood flow in the arteries and veins

CT scan

to visualise blood vessels and tissues in different parts of the body

MRA scan

to visualise blood flow and condition of the blood vessel walls


to measure heart rate and provide visualisation of electrical impulse conduction through the heart


to visualise heart beating and pumping blood


to visualise lumen of blood vessels and heart chambers


to visualise blood flow in the veins

Blood tests

to monitor how well the blood can clot