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Complications of Diabetes

Winning the battle against CHD - Understanding Atheroma

Introduction

Over a quarter of a million people die in the UK each year from heart disease and stroke. In this information sheet, we will show you the underlying cause of cardiovascular disease and what can be done to prevent it.

What is atheroma?

Think of your blood vessels as pipes carrying essential water to your house. The walls of the pipes over time may become rusty, eventually leading to the pipe becoming blocked and your water supply being cut off. These days, pipes are made of plastic, however they do become furred up with chalk deposits.

Inside a blood vessel A typical pipe which has become furred up

Atheroma starts off like the pipes in the pictures above, the plaques of ‘rust’ instead consisting of fat and fibrous tissue which develop because of the body’s reaction to the plaque. Initially as in the first photograph, when the plaques are small, water gets through the pipe and blood gets through the artery.

Plaques of atheroma lead to turbulent blood flow. Later on as the pipe becomes narrow the flow of water becomes sluggish.

There are reasons why people who have diabetes readily form fatty plaques. Platelets, which are tiny cells in the blood stream essential for clotting, tend to be more sticky in people with diabetes. The plaque of atheroma provides an ideal place for these blood cells to stick to.

The photograph below shows an actual blood vessel, which has been affected by a build up of atheroma. The lining of this vessel should have been perfectly smooth as in the second photograph which just has a few fatty streaks.

 An actual blood vessel, which has been affected by a build up of atheroma A normal blood vessel which should look smooth

Why are people who have diabetes more prone to atheroma?

The lining of normal blood vessels (called the ‘endothelium’) is smooth and does not attract particles from the blood stream. In people who have diabetes, the inner lining of blood vessels,  develop atheroma more easily. This is known as ‘endothelial dysfunction’. Think of this as a diffuse process affecting the entire circulation. This increased risk of atherosclerosis is why diabetologists are often pre-occupied with  cardiovascular disease.

What happens when ‘the pipes’ become blocked?

The symptoms you get when blood vessels become blocked depend on where the block is and also the severity of the block. Usually this process does not cause any symptoms until the blockage is fairly advanced. When blood vessels supplying the heart become ‘furred-up’ on the inside and partially blocked, the blood flow becomes sluggish and cannot increase in response to exercise. When you try to exercise, the heart muscle does not receive enough oxygen which leads to pain or ‘angina’.

A heart attack happens as a result of a blood vessel becoming blocked off. This is thought to be due to a rupture of a atheromatous plaque which causes a clot or ‘thrombus’ to form. This clot blocks the vessel completely causing an area of heart muscle to be deprived of oxygen and vital nutrients. The area of muscle supplied is damaged as a result. How much damage occurs depends on where the block happens.

What can be done to prevent this happening?

There is a lot that you can do to improve your ‘endothelial function’ and reduce risk of developing atheroma.

  • Take regular exercise
  • Stop smoking
  • Eat sensibly
  • Lose weight if overweight
  • Control your blood sugar

Over a period of time these measures will help your blood vessels work more effectively and reduce the build up of fatty deposits.

There are several drugs which have been shown to improve ‘endothelial function’. Statins (cholesterol lowering drugs), ACE inhibitors and the thiazolidenediones (Glitazones) have all been shown to help keep blood vessels healthy. 

 

Dr Nishan Wijenaike MD, FRCP
Consultant Diabetologist
West Suffolk Diabetes Service
Bury St Edmunds
Original article September 2004
Updated November 2007