Sacramento HeartScan

Coronary Calcium Scoring: A Guide for Physicians

According to statistics from the American Heart Association, coronary heart disease is the leading cause of death among American men and women, with estimates that nearly 59 million Americans have one or more forms of cardiovascular disease.

With recent technological improvements in helical (spiral) CT scanners, coronary calcium scanning (CCS) has become a widely available, cost-effective tool for the early detection of coronary artery disease (CAD). Sacramento HeartScan's GE Lightspeed Ultra is the fastest next generation high resolution helical CT scanner that uses the new technique of gating image acquisition to the ECG to accurately assess coronary calcium. This gating process allows only those images acquired during diastole to be utilized for the analysis of coronary calcium.

Know the Score

The presence of any amount of coronary calcium in a CT scan indicates that underlying CAD is present. The amount of calcium detected is rated as a “calcium score.” That score provides an evaluation of the patients CAD. Only plaque that is calcified will show up in a CT scan, so it must be remembered that minimal atherosclerotic changes may be missed in a CT scan. The CT scan should be used as an additional powerful tool in the diagnosis of CAD.

• If a patients scan results in a score of 0, there is an absence of detected calcium. A score ranging from 0 - 10 indicates the presence of plaque, but a good prognosis can be assumed.

• A score between 10 and 400 is indicative of a moderate plaque burden and is associated with an intermediate, although significant, risk of future cardiac events (especially if the score is greater than 100).

• A score higher than 400 implies extensive CAD with a likelihood of greater than 90% that at least one vessel is significantly obstructed. These patients would be considered at high risk.

• Age and gender must also be taken into consideration when evaluating a calcium score. A score that is “average” for a 60 year old male would not be average for a 40 year old female.

• A CCS report from Sacramento HeartScan will rank the patient by percentile based on age and gender. Calcium score guidelines will be included to assist in determining a course of action for treatment.

Calcium Score Guidelines
Calcium Score	Plaque Burden	Probability of Significant CAD	Implications For CV Risk	Recommendations
0	No identifiable plaque	Very low, generally <5%	Very Low	Reassure patient. Discuss general public health guidelines for primary prevention of CV disease.
1-10	Minimal identifiable plaque burden	Very unlikely, <10%	Low	Discuss general public health guidelines for primary prevention of CV diseases.
11-100	Definite, at least mild atherosclerotic plaque burden	Mild or minimal coronary stenosis likely	Moderate	Counsel about risk factor modification, strict adherence with primary prevention goals. Daily aspirin.
101-400	Definite, at least moderate atherosclerotic plaque burden	Non-obstructive CAD highly likely, although obstructive disease possible	Moderately High	Institute risk factor modification and secondary prevention goals. Consider exercise testing for further risk stratification. Daily aspirin.
>400	Extensive atherosclerotic plaque burden	High likelihood (>90%) of at least one significant coronary stenosis	High	Institute very aggressive risk factor modification. Consider exercise or pharmacologic nuclear stress testing to evaluate for inducible ischemia. Daily aspirin.

CT Scans and Other Cardiac Tests

• CCS is used to determine the presence of early CAD and the extent of plaque burden. It is not helpful in locating significant coronary stenosis or in defining clinical prognosis. A patient with significant coronary calcium should be considered for an exercise or pharmacologic nuclear stress test for further evaluation.

• CT scans are not appropriate for evaluating valvular structures and valvular function. This is still best accomplished with echocardiography.

• CCS is not a replacement for coronary angiography. Currently, coronary angiography represents the only reliable technology for accurately assessing luminal narrowing within the coronary circulation.

• Evaluating pericardium in patients with suspected constrictive pericarditis may be accomplished with CT scanning in patients with suspected right ventricular dysplasia.

How To Determine If Your Patient Should Have A CT Evaluation

• If treatment of a patient would be influenced with the detection of CAD

• Borderline lipid levels

• Mild hypertension

• Family history of premature CAD

• In patients with cardiomyopathy, to assess whether it is likely ischemic in etiology

• Younger patients presenting atypical symptoms

Early Detection

In the past, the first diagnosis of CAD wasn't made until the patient showed symptoms, had an abnormal response to stress testing, or underwent a coronary angiogram. But at this point, the atherosclerotic process would already have been well-advanced. With early detection through CT scanning there is now an opportunity to approach CAD from the standpoint of prevention through changes in lifestyle choices. Calcium deposits (the marker for coronary atherosclerosis) can now be detected in very small amounts.

Contraindication

• There is no contrast administered, no need for IV access, no fasting, no changes in medication, no restrictions regarding pacemakers or prosthetics.

• Not recommended for patients with arrhythmias; image quality would be compromised due to difficulty in adequate cardiac gating.

• Because of x-ray exposure, pregnant women should not undergo a CT scan.