Intima-Media Thickness, a New Accurate Tool to Assess Cardiovascular Risk

Cardiovascular disease predictors: more than just the conventional risk factors

Cardiovascular disease is a major cause of death worldwide. Conventional cardiovascular risk factors such as diabetes, hypertension, hyperlipidaemia, family history of premature coronary heart disease and cigarette smoking do not fully explain the high rate of coronary heart disease and stroke globally. Direct assessment of vascular health in conjunction with conventional risk factor may give greater predictive value in future development of premature coronary heart disease and stroke.

What is Intima-Media Thickness
Over recent years, it is becoming increasingly clear that direct measurement of the blood vessel wall thickness, medically known as the intima-media thickness (IMT) of the neck arteries (common carotid arteries) by B-mode ultrasound is a useful method in cardiovascular risk assessment. Common carotid IMT has been shown to correlate with traditional vascular risk factors and may predict the likelihood of heart attacks and stroke. Measurement of carotid IMT is convenient, non-invasive, painless, accurate, reproducible and inexpensive.

How does Intima-Media Thickness Help You
Early detection of hardening of arteries, medically known as “atherosclerosis” in high risk individuals is unquestionably beneficial. First, it gives a visual warning signal to the high risk individuals and this may aid certain behavioral changes such as quitting smoking and weight reduction. Second, it alerts both the patient and the physician the need to treat traditional vascular risk factors (such as LDL-cholesterol) to target. Third, early pharmacological intervention may change the outcome and several drugs may even decrease IMT in high risk populations. For example, statin drugs which are used to lower cholesterol, have been shown to decrease carotid IMT.

Can We Do Something to Decrease the Intima-Media Thickness and Our Cardiovascular Risk
In patients with type 2 diabetic patients, cilostazol significantly decreases carotid IMT after one year. Furthermore, thiazolidinediones (a group of anti-diabetic drugs) have been shown to have positive effects on carotid arterial wall thickness in people with diabetes. The gold standard first line anti-diabetic drug, metformin, has been shown to decrease IMT progression in Japanese type 2 diabetic patients over a period of 2 years. Similarly, acarbose slows the progression of IMT over 3 years in subjects with impaired glucose tolerance.

The Way Forward
In the present day and age, measurement of the carotid artery IMT should be part of cardiovascular risk assessment in addition to the conventional risk factors. The visual impact of these scans would clearly help behavioral modification and drug compliance in high-risk individuals.



Dr. Norman N. Chan FRCP, MD

Clinical Director, Qualigenics Diabetes Centre (http://qualigenics.com)
Norman Chan is a specialist in Endocrinology and Clinical Director of Qualigenics Diabetes Centre, GenRx of HKR International, in Hong Kong. More on Dr Norman Chan's biography here.