Measuring Cholesterol Buildup
Thomas Perry, MD, a cardiologist in Phoenix since 1989, is on staff at Banner Estrella Medical Center, with offices located at 10815 W. McDowell Road in Avondale and 5251 W. Campbell Ave. in Phoenix.
Question: My doctor is concerned about a build up of cholesterol plaque in my arteries and has suggested I have a Coronary Artery Calcium Score (CACS). What exactly is that and how accurately can it predict future heart problems?
Answer: The CACS is done with a CT X-ray machine. There have been over 1,000 studies validating the prognostic value of this score.
Calcification occurs within cholesterol deposits as they grow and age on the inner lining of the arteries. The calcium can be seen and measured by CT scans, whereas cholesterol itself is invisible to X-rays. The quantity of cholesterol plaque is proportional to the quantity of calcium. Therefore an individual’s total coronary cholesterol plaque burden is measured by the calcium score. The higher the score the worse the prognosis and the greater the need for anti-cholesterol treatment.
The CACS is not a risk factor, but rather a direct measure of coronary disease.
Many studies have shown that the cholesterol profile by itself, as measured in the blood, is only weakly predictive of heart attack, stroke and sudden death. Other factors have a greater influence. These include age, gender, diet, exercise, genetics, blood pressure, diabetes, and smoking.
But the CACS by itself has been shown to be more predictive of major cardiac events than scores combining all of other measurable risk factors including age. The Society for Heart Attack Prevention and Education recommends that all men at age 45, and women at age 55 should be checked with a CACS.
If you have a high CACS, your prognosis is not good. In such cases I recommend aggressive treatment to greatly lower the cholesterol, which will slow or reverse the growth of plaque.
In some cases, stress testing may also be needed to see if you have severe blockages, even higher risk, and therefore a need for a stent or heart surgery. When we determine risk in this way, we can prevent heart attacks and extend life with proper treatment.