Friday, February 24, 2006

Heart Tests: Coronary angiogram

Here is part 19 of the heart of the matter. Please read the disclaimer here and you can find part 18 here.

Now is a good time to review the basics. Coronary: as for the heart, angios: blood vessels, gram: picture. A coronary angiogram then is to make a picture of the arteries of the heart.

In the invasive form we invade the body, as in cutting or passing tubes into the body. Just a simple injection into a vein is not generally considered to be invasive. There is almost no controversy about the position of the invasive coronary angiogram as the "gold standard" to diagnose CAD. As for the use or as some would allege, misuse, of the non-invasive coronary angiogram, it is certainly very controversial at the moment.

Much has been written about it recently, on the one hand by heads of professional societies and on the other hand by professionals who have equity stakes in the machines!!! It is not the purpose of this blog to join in the debate however much joy it may give the readers but hopefully I can provide a simple, balanced view on this subject and leave the readers to draw their own conclusions.

DISCLAIMER: I am not a stakeholder in any way in any of the 4 MSCT (multi-slice computerized tomography) machines around Kuala Lumpur, or the 8 machines around the country. The number of machines may have increased by the time you read this.

It is true that if you suspect that you may have coronary artery disease (CAD), no amount of blood tests or ECG or echocardiogram will convince you one way or the other, until you see your arteries. For a long time, before the advent of computers and their sophisticated software, we relied on the invasive coronary angiogram as the gold standard.

Presently, with our advanced computers, hardware and software, we can image coronary arteries non-invasively. The pictures of your heart and heart arteries are really seductive, but is what you see the real arteries or is it just computer generated virtual arteries brought to you via the miracle of software processing? What is the clinical correlation through clinical studies between the "gold standard coronary angiogram", and the CT coronary angiogram? Are there enough clinical studies? What is the international experience?

In part 20 we talk about invasive angiograms.

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