The benefits of CT when identifying heart disease

Angiogram vs CT scan

In the not too distant past the only way you could tell if your arteries were furring up was if you had an angiogram of your coronary arteries.

What is an angiogram?

An angiogram is an invasive process which checks for blockages in your cornary arteries. A tube is inserted into your femoral artery in the groin and manoeuvred round to the heart. Dye is then injected into the heart so that it flows through the coronary arteries. You could then see if there were any blockages or narrowing.

How are CT scanners being used to identify heart disease?

Today, modern CT scanners have revolutionised the ability to see arteries and now a quick thirty-minute (ish) scan with a simple injection of dye into your arm, can produce highly accurate pictures of your coronary arteries.

This has transformed imaging for heart disease and is now recommended by NICE.

Heart disease and plaque

The use of CT scanners has also turned on its head our thinking of heart disease. When I started in medicine, and for many, many years heart disease was really all about plumbing. Your pipes furred up and when they reached a critical narrowing, usually 80- 90% you would develop angina; chest pain on effort and be at risk of a heart attack.

Narrowing of the arteries is all due to fatty plaques furring up the arteries. Early on it was discovered that these plaques tended to become calcified and so early CT scanners would undertake what’s known as a calcium scan; which essentially look at how much calcium was in your arteries. This was a reasonable proxy for your risk of heart disease.

However, as technology advanced, we realised that most people having heart attacks aren’t severely furred up; they probably have blockages of just 30-40%.

It became apparent that there were different forms of plaques which cause the narrowing and blockage of arteries;

Calcified

Soft plaques

A mix of soft and calcified.

The soft plaques are the ones that are at risk of rupture.

Calcified plaques tend to be more stable; indeed, it is known that statins help stabilise plaques and some studies have shown patients on statins tend to have more calcified plaques.

So, we’ve moved away from the original and ‘early’ plumbing model to one where it is crucial to understand the types of plaques you have so that treatment can be tailored to your risk.

How effective are CT scanners for identifying heart disease?

Coronary artery CT is excellent at being able to determine plaque types. One of the benefits of this type of scan is that if it’s negative then you can be 99% certain you don’t have heart disease and that’s likely to hold true or at least eight years going forward.

CT scanning coronary arteries have certainly been a game changer in healthcare, and we’re looking to start offering this service in the Autumn.