Heart disease is the number one cause of death in the United States of America and in most developed countries. This is despite routine screening and treatment of diseases such as hypertension, diabetes, and high cholesterol that are known to cause heart disease. Although individuals with these diseases suffer higher rates of heart disease than those who don’t, it’s well recognized that heart disease does indeed occur in individuals without the above-mentioned risk factors. In fact, many with heart disease don’t discover they have it until they experience out right symptoms such as weakness, exertional pain, or shortness of breath. Sadly, many don’t know until they suffer a stroke or heart attack. Since heart disease is so often, life altering, if not deadly, patients and doctors alike should seek sensitive, non-invasive and cost-effective methods to recognize heart disease in its earliest stages, especially in those who lack traditional risk factors. A measurement of the carotid artery intima media by ultrasound is proven to identify heart disease in those lacking risk factors for heart disease and those with moderate risk.
Carotid artery intima media testing (CIMT) is an ultrasound measurement of the thickness of the two innermost layers of the carotid artery. The intima is where the earliest changes within the heart occurs. In several studies, its thickness is highly correlated with not only heart disease, but with events such as heart attack and stroke. In other words, as the width of the measured tissue increases, the rate of events so too increases.
CIMT is highly accurate and reproducible according to the 2010 report by the American College of Cardiology Foundation/ American Heart Association Task Force on Practice Guidelines (1). The authors conclude that CIMT is associated with risk of heart attack and stroke independent of traditional risk factors. CIMT adds value in predicting risk in those with established heart disease as well. Roumeliotis et el., found that CIMT is a “strong and independent” predictor of cardiovascular related death in patients with type II diabetes and chronic kidney disease (2). In 2015, Cobble et al., affirm that carotid intima-media thickness can detect subclinical disease in low risk patients (3). A 2017 study published in the Journal of the American Heart Association found that carotid intima-media thickness is correlated with heart disease across different ethnic groups and again, adds predictive value above and beyond the traditional Framingham risk factors (4). Carotid artery intima media thickness measurement can also be used to assess response to therapy as success should find stabilization if not decreases in intima media thickness.
Testing is performed by a certified sonographer who places an ultrasound probe over each carotid artery. The examination takes just fifteen minutes and does not involve radiation. If the description of this test sounds familiar, you are thinking of a carotid ultrasound. A carotid ultrasound should not be confused with CIMT. Although a carotid ultrasound is performed similarly, the two tests measure entirely different endpoints and have a drastically different interpretive value. CIMT detects heart disease in the earliest stages while a carotid ultrasound detects the disease in moderate and late stages only. Most importantly, CIMT can detect heart disease in those lacking traditional risk factors, i.e., those who might be deemed not at risk or those with equivocal risk. CIMT takes just fifteen minutes to perform and because it typically costs less than three hundred dollars, it is considered relatively inexpensive for the valuable information gained.
Heart disease remains the number one cause of death in America. In many, heart disease progresses unknowingly and even in those without identifiable risk factors. Because of the sensitivity in which CIMT can detect heart disease, even in low and moderate risk individuals, CIMT can be used by physicians and patients to determine disease risk and if more aggressive treatment measures are needed. Since CIMT is noninvasive and relatively inexpensive, CIMT should be used to periodically assess response to therapy.
References
- Greenland P, Alpert JS, Beller GA. 2010 ACCF/AHA guideline for assessment of cardiovascular risk in asymptomatic adults: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. American College of Cardiology Foundation; American Heart Association. J Am Coll Cardiol. 2010 Dec 14;56(25):e50-103
- Roumeliotis A, Roumeliotis S, Panagoutsos S. Carotid intima-media thickness is an independent predictor of all-cause mortality and cardiovascular morbidity in patients with diabetes mellitus type 2 and chronic kidney disease. Ren Fail. 2019 Nov;41(1):131-138.
- Polak JF, Szklo M, O’Leary DH. Carotid Intima-Media Thickness Score, Positive Coronary Artery Calcium Score, and Incident Coronary Heart Disease: The Multi-Ethnic Study of Atherosclerosis. J Am Heart Assoc. 2017 Jan 21;6(1).
- Cobble M, Bale B. Carotid Intima-Media Thickness: Knowledge and Application to Everyday Practice. Postgraduate Medicine. Vol 122, 2010-Issue 1:10-18
