What is CIMT study?
Measurement of carotid intima-media thickness (CIMT) in the carotid artery with an ultrasound is a non-invasive, sensitive, and reproducible technique for identifying and quantifying subclinical vascular disease and for evaluating Cardiovascular Disease (CVD) risk – heart attacks and strokes and also to predict future cardiovascular disease (heart attacks and strokes) risk.
Measuring CIMT and identifying carotid plaque can be useful for refining cardiovascular disease risk assessment in patients at intermediate cardiovascular disease risk (i.e. patients with a 6%-20% 10-year risk of myocardial infarction or coronary heart disease death who do not have established coronary heart disease or coronary disease risk equivalent conditions).
Who is to do the CIMT (measuring CIMT & identifying carotid plaques)?
(1) Patients at intermediate CVD risk (i.e. 6%-20% 10-year risk for myocardial infarction or coronary heart disease death who do not have established coronary heart disease or coronary disease risk equivalent conditions)
(2) Family history of premature coronary heart disease (heart attacks and strokes) in a first-degree relative;
(3) Younger than 60 years old with severe abnormalities in a single risk factor who otherwise would not be candidates for pharmacotherapy;
(4) Women younger than 60 years old with at least two coronary heart disease risk factors.
(5) If the level of aggressiveness of therapy is uncertain and additional information about the burden of subclinical vascular disease or future coronary heart disease (heart attacks and strokes) risk is needed.
(6) Reclassify patients at intermediate risk, discriminate between patients with and without prevalent coronary heart disease, and predict major adverse coronary heart disease (heart attacks and strokes) events.
Coronary Heart Disease (CVD) risk factors (Risks for developing heart attacks and strokes):
c. Raised total cholesterol, raised triglycerides, raised LDL cholesterol, raised ratio total cholesterol/HDL and reduced HDL cholesterol
d. Overweight and obesity
f. Male above 35 years old and post menopausal women.
g. Family history of heart attacks and stroke.
h. Medical history of arrhythmias (irregular heart beat)
i. Transient Ischemic Attack (TIA)- minor stroke
j. Peripheral Arterial Disease (PAD) – narrowing or blockages of arteries in the legs.
When does atherosclerosis starts?
Atherosclerotic vascular disease begins in childhood and progresses over decades.
Symptomatic, clinical cardiovascular disease (CVD) events generally occur when atherosclerosis progresses to flow limiting disease that causes ischemia, or when a thrombus forms on an existing plaque as a result of rupture or erosion.
Although not everyone with underlying atherosclerotic plaque will experience a clinical CVD event, the greater the degree of subclinical atherosclerosis, the greater the risk for future cardiovascular events.
To prevent death and morbidity from CVD, there is great interest in identifying asymptomatic patients at high risk who would be candidates for more intensive, evidence-based medical interventions that reduce CVD risk.
How are we going to identify atherosclerotic changes in the arteries?
Imaging of carotid arteries using CIMT study to identify and quantify thepresence of subclinical vascular disease has been suggested to further refine CVD risk assessment.
As a screening test, imaging must be safe, be sensitive, be affordable, and lead to interventions that can favourably alter the natural history of CVD.
Measurement of carotid intima-media thickness (CIMT) with B-mode ultrasound is a non-invasive, sensitive and reproducible technique for identifying and quantifying atherosclerotic burden and CVD risk.
CIMT is a well-validated research tool that has been translated increasingly into clinical practice.
Endorsement by the Medical Leaders for CIMT study
1. The United States Centers for Medicare and Medicaid has established a Current Procedural Terminology code (0126T) for “Common CIMT study for evaluation of atherosclerotic burden or coronary heart disease risk factor assessment.”
2. In 2000, the American Heart Association Prevention Conference V concluded that CIMT “can now be considered for further clarification of coronary heart disease (CHD) risk assessment at the request of a physician,” provided that it is performed by an experienced laboratory.
3. In 2001, the National Cholesterol Education Program (NCEP) Adult Treatment Panel III stated that CIMT “could be used as an adjunct in CHD risk assessment . . . the finding of an elevated CIMT (e.g. 75th percentile for age and sex) could elevate a person with multiple risk factors to a higher risk category. This expert panel concluded that “if carried out under proper conditions, CIMT could be used to identify persons at higher risk than that revealed by the major risk factors alone.”
Disclaimer: This is only general information. A doctor should be contacted if you need any medical advice or if medical decisions need to be made.