Coronary Artery Calcium Scan

Disease Management Above the Standard 

he first manifestations of heart disease is sudden death or acute heart attack in 62% of men and 42% of women. In addition to the human toll, there is a tremendous economic burden to America. Largely preventable cardiovascular disease supports and sustains a large cardiovascular healthcare industry. The best way to put a stop to the favored status quo is to identify those who are likely to have these events earlier and use proven medical therapy to stop disease progression. If you are male age 45 and older or female age 55 and older, with diabetes or other risk factors like high blood pressure, smoking, family history, high LDL cholesterol or low HDL cholesterol, consider getting your coronary calcium score.

Dual Approach

There is no single test that reliably predicts the risk for everyone. Framingham Risk Score is not based on the actual presence or absence of atherosclerosis. It is based on the presence of a limited combination of risk factors. The Framingham 10 Year Risk Score does not incorporate family history of premature CHD. A man and a woman with identical risk factors, a woman may have to wait 20 years later than a man before becoming eligible for aggressive preventive treatment. A nuclear stress test becomes positive only in the advanced stage when an artery is already severely obstructed. 

Detect Your Plaques Earlier and Live

Coronary calcium score test is based on the actual presence or absence of calcified plaques due to atherosclerosis, not risk factors. And if atherosclerosis is detected, it also estimates the amount of plaque burden. Some individuals with a Framingham Risk Score of less than 20% may actually be high risk. For this intermediate risk group, coronary calcium score is a good test option. In selected patients, 256 slice cardiac CT for coronary calcium score can be very helpful in directing therapy. The actual test only takes 30 seconds. There is no injection or special preparation needed.

Atherosclerosis is a progressive and diffuse disease. Early detection is important because medical treatment is highly effective. A nuclear stress test detects only severe plaques causing more than 60% to 70% obstruction - a late stage. The presence of calcium in the coronary arteries can be detected much earlier, many years or decades, before a nuclear stress test becomes positive. A nuclear stress test takes 4 hours to complete and costs over 20 to 50 times more.

Two cases showing the limitations of the traditional Framingham Risk Analysis. Both were asymptomatic male patients, with normal EKGs and stress tests, were supposedly at intermediate risk but weren’t.

The above is an example of a normal study - Zero Coronary Calcium Score. Patient is at low risk and statin treatment is usually not needed. Their survival rate is 99% in 10 years. Their need to utilize expensive cardiovascular healthcare resources is very low - a cost saving. 

The above is an example of an abnormal study, one with very plaque burden with a coronary calcium score of 1075. This patient is at high risk for heart attack, vascular death, stroke, angina, need for cardiac hospitalizations, stents and even heart bypass in the near future. He needs aggressive lipid-centered optimal medical therapy to halt plaque progression, prevent plaque rupture and induce plaque regression.

A coronary calcium score of over 100 is associated with 10 times more cardiovascular events in the next 10 years compared to those with lower scores. It is similar for men and women, young and old, for whites, blacks, hispanics and asians (MESA Study). Compared to other risk prediction algorithms, coronary calcium score is the most robust. Cardiovascular events include heart attack, sudden death, stroke, need for cardiac hospitalization, stent and heart bypass - all of these cost many tens of thousands of healthcare dollars. Patients who knew that they have high calcium score are seven times more likely to adhere to treatment. Effective treatment to reduce annual increase in calcium score to less than 15% per year is our goal. Follow up coronary scan in 3 to 5 years is recommended depending on the number of risk factors and response to treatment.

Redefining Heart Attack Risk

Traditionally, calculation based on age, sex, total cholesterol, HDL cholesterol, smoking and blood pressure determines the level of heart attack risk over the next ten years. The main limitation of the method is that it is not based on whether atherosclerosis is present or not. Using the approach, approximately 60% of adults worldwide are classified intermediate risk for a coronary event. Misclassification is very common. Many are in fact low risk and some are high or very high risk. There is cost to this misclassification - giving treatment to those at low risk who don’t need it while not providing optimal medical therapy to those at high and very high risk who need plaque stabilization-regression therapy.

The above slide represents 82,214 CACS cases in the International CACS Outcomes Registry. Data acquired from 33 medical facilities in 7 countries between 2012-2014. All patients were intermediate risk, asymptomatic, and without known CAD at time of CACS.

Here is the breakdown shown in the above slide: 33,661 (41%) of patients had zero calcification. 59% of intermediate risk patients had some level of CAD. 28,263 (34%) had a CACS score of 1-99. 9,568 (12%) had a CACS score of 100-399. 10,722 (13%) had a CACS score >400. 2,801 (3%) had a CACS score >1000. 

Among the patients with scores >1000, 82% went on to interventional procedures (56% Stent, 26% Coronary Bypass Surgery). 

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Coronary Plaque Stabilization, Regression and Calcification

Capture - CACS 2002

This patient had an EBT for coronary artery calcium scan after his brother died suddenly of a heart attack in 2002. His treadmill nuclear stress test was normal. Baseline Agatston score was 616 with plaques in the left main, LAD, Lt Cx and RCA. On the first scan, only about a third of the plaques have calcifications. Because of heavy plaque burden, he had coronary arteriogram afterwards - the first and only time. It showed no obstructive disease.

Advanced Cholesterol Therapy is the Cornerstone

Plaque-directed, lipid-centered initial medical therapy was implemented using statin + ezetamibe to maintain LDLc under 50 mg/dl for 5 years and under 70 mg/dl thereafter. BP was optimized with ramipril. He is not a diabetic and does not smoke.

Above is the projected compounded annual increase in Agatston score for the next five years - from 5% to 50% using Excel spreadsheet. 

CACS trend over 13 years

After the initial CACS by EBT of 616, this 60 year old patient received aggressive lipid therapy and his LDLc was maintained between 40 mg/dL to 60 mg/dL since 2002. We decided to have follow-up studies which spanned over a period of 13 years. The first follow up EBT was one year later which was 811 which was an increase of 35% per year for the first year but subsequent follow up showed flattening of the trend. The score of 765 after 5 years is about a 10% increase or about 2% per year. After 13 years, it was a 25% increase from year 1 - about 2% per year increase. Below 15% per year after 5 years is considered a sign of atherosclerosis stabilization and regression. 

Capture - 1075

The above is after 11 years.

Capture - CACS 2015

The above is after 13 years.

Patient remains in good health, completely asymptomatic and without any cardiac hospitalization. His most recent stress test remains normal.

Plaque Progression or Regression

Net Balance-2

Plaques are biologically active and within it, there are both injury and repair processes going on. Whether progression/plaque rupture or regression occurs depends on which process is dominant.

Calcification is a marker for plaques - calcification is present in the coronary arteries only if there are plaques. Calcifications may increase with aggressive statin therapy during the first few years but the rate of annual increase slows down over time.

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