| Cardiovascular disease is the leading cause of death in | | | | 65 year old male but grossly abnormal for a 55 year |
| men and women in the United States. Approximately | | | | old female. |
| 50% of acute myocardial infarction's occur in people | | | | The calcium scoring scan is not able to identify the |
| without any history of coronary artery disease. | | | | location of a significant coronary artery lesion nor |
| Sudden cardiac death is often the first sign of | | | | identify the percent stenosis. The quantity of coronary |
| coronary heart disease. Coronary atherosclerosis is a | | | | artery calcium predicts the total atherosclerotic plaque |
| slow progressive disease that oftentimes goes | | | | mass and likelihood of developing future cardiovascular |
| unrecognized until the person develops symptoms. By | | | | events. Coronary calcium has been reported to be an |
| the time symptoms start to occur coronary artery | | | | independent predictor of stable angina, myocardial |
| disease is usually in a relatively advanced stage | | | | infarction, cardiovascular death, and need for coronary |
| requiring either percutaneous or surgical | | | | revascularization. A study in asymptomatic adults 20 to |
| revascularization. The opportunity for disease | | | | 69 years old found that at 18 month follow-up the |
| prevention or aggressive risk factor modification is | | | | myocardial infarction and cardiovascular death rate |
| missed. What is needed is a way to identify | | | | was 6.6% in people who had any calcium present on |
| asymptomatic people who are at high risk for | | | | scan versus 0.9% in people without any calcium. There |
| cardiovascular events early in their disease process. | | | | is a direct relationship between increasing calcium |
| Traditional cardiovascular risk factors are well | | | | scores and the occurrence of adverse events. |
| established (elevated lipid levels, hypertension, smoking, | | | | Asymptomatic people with very high calcium scores |
| obesity, lack of exercise, diabetes, family history heart | | | | (> 1,000) have been found to have an approximately |
| disease) and helpful to predict future cardiovascular | | | | 25% risk per year of developing a myocardial |
| disease. Many people however suffer cardiovascular | | | | infarction of cardiovascular death. A recent study of |
| events in the absence of these established coronary | | | | asymptomatic adults over 45 years of age with at |
| artery disease risk factors. | | | | least one cardiovascular risk factor found a fourfold |
| Myocardial infarctions usually occur in patients who | | | | increase in cardiovascular risk in patients with coronary |
| have a mild of moderate coronary artery stenosis that | | | | artery calcium scores greater than 300. A study |
| develops plaque rupture and leads to an acute | | | | performed on symptomatic patients found that a |
| thrombosis. These mild to moderate coronary lesions | | | | coronary artery calcium score greater than 170 was |
| may not cause symptoms and/or may not cause | | | | associated with an increased likelihood of obstructive |
| enough ischemia to be picked up during a routine | | | | coronary artery disease regardless of the number of |
| stress test. | | | | risk factors present. |
| During the early stages of coronary atherosclerosis | | | | A recent meta-analysis reported a 92.3% sensitivity |
| calcium starts to accumulate within the plaque. As the | | | | and 51.2% specificity for the accuracy of the EBCT to |
| atherosclerotic process progresses the amount of | | | | diagnose obstructive coronary artery disease. This |
| calcification increases. During the advanced stages of | | | | makes the overall predictive accuracy approximately |
| atherosclerosis a large amount of coronary | | | | 70%. One advantage of the scan is there are no |
| calcification may be present. | | | | "false positive" scans, calcium deposits are only found |
| Women have been reported to have less coronary | | | | in the presence of plaque. Interscan reliability of calcium |
| artery calcification than men and the mean prevalence | | | | scores has been questioned and has been reported to |
| of calcification in women occurs about one decade | | | | vary more with lower score. One study reported a |
| later than in men, as does the incidence of | | | | calcium score variability of 28% in women and 43% in |
| cardiovascular events. The prevalence of calcium in | | | | men when repeat scans were performed on the |
| adults 30 to 39 years of age is 21% for men and 11% | | | | same individual. This really needs to be evaluated |
| for women, while in adults 40 to 49 years of age the | | | | further and may be dependent on the facility, |
| prevalence is 44% in men and 23% in women. A | | | | equipment of physician interpreting the results. |
| recent study found coronary calcium scores were | | | | Non-calcified, soft plaques will not be detected by |
| similar in African American and Caucasian women | | | | EBCT. Younger patients who are heavy smokers |
| even though African American women had more risk | | | | may not have calcium deposits present but are still at |
| factors. Diabetes mellitus and not exercising regularly | | | | high cardiovascular risk and prone to spasm and |
| was associated with increased Coronary Artery | | | | thrombus formation. There has been some research |
| Calcium Scores in white women but not African | | | | to suggest that patients with unstable angina are prone |
| American women. The overall prevalence of calcium in | | | | to have fewer calcified plaques than patients with |
| women is about half that of men until age sixty. | | | | stable angina. Younger patients may develop a |
| Another study in asymptomatic women found that | | | | significant stenosis in the absence of calcification. This |
| smoking, elevated total cholesterol levels, and | | | | may falsely reassure people who are at high risk. |
| hypertension were all associated with higher Coronary | | | | There is not enough data to support using the |
| Artery Calcium Scores. Calcium deposits have also | | | | coronary calcium scans in symptomatic patients of |
| been found to increase with age irrespective of | | | | patients already know to be at high risk. |
| gender. Patients with diabetes and patients with end | | | | The coronary calcium scan (EBCT) is most useful in |
| stage renal disease requiring hemodialysis have a | | | | asymptomatic patients with intermediate risk, to help |
| higher prevalence of calcium. The more cardiovascular | | | | determine the need for aggressive risk factor |
| risk factors a person has the higher the prevalence of | | | | management. (See Coronary Artery Calcium Scans |
| calcium. | | | | chart below) |
| Atherosclerosis is the only disease process known to | | | | Traditional non-invasive tests to evaluate coronary |
| cause calcium to deposit in coronary artery walls. | | | | artery disease (exercise stress test, nuclear scans, |
| Calcification is not a degenerative disease, it is not a | | | | stress echocardiography) only detect coronary lesions |
| part of the "normal" aging process. Calcium is not | | | | that are severe enough to limit blood flow and cause |
| found in normal coronary arteries. | | | | myocardial ischemia. People with very mild coronary |
| Since calcium deposits start to develop during the early | | | | artery disease or early atherosclerosis will not be |
| stages of atherosclerosis and if we are able to identify | | | | identified. Coronary calcium screening is able to identify |
| the presence of calcium we are able to identify | | | | non-obstructive mild coronary artery lesions before |
| preclinical coronary artery disease during the | | | | symptoms develop. Asymptomatic people with high |
| asymptomatic stage. This can allow for the | | | | calcium scores are also more likely to have abnormal |
| implementation of early aggressive risk factor | | | | nuclear stress tests indicative of silent ischemia. In one |
| reduction. | | | | study 46% of patients with coronary artery calcium |
| The calcium score screening heart scan is a | | | | scores greater than 400 had an abnormal nuclear |
| non-invasive test that detects calcium deposits in the | | | | scan while 0% of patients with coronary artery |
| coronary artery walls. The test is performed with an | | | | calcium scores less than 10 had an abnormal nuclear |
| electron beam cat scanner (EBCT) that permits very | | | | scan. |
| rapid scanning. The images are triggered with the | | | | EBCT scans may proved to be more beneficial for |
| assistance of ECG monitoring during diastole and a | | | | screening women. Many times women present with |
| several second breath hold to eliminate motion artifact. | | | | atypical symptoms and are more likely to have false |
| The actual scan only takes about thirty seconds and | | | | positive exercise stress tests and/or nuclear scans. |
| computer software then quantifies the calcium area | | | | Calcium scoring scans have been reported to have a |
| and density. | | | | higher predictive value for significant coronary artery |
| The EBCT detects the presence, location and extent | | | | disease in women and less false positives than men. |
| of calcium deposits in the coronary system. Separate | | | | The negative predictive value in one study of |
| calcium scores may be obtained for the left main | | | | symptomatic patients was 96% in women and 89% in |
| artery, left anterior descending artery, left circumflex, | | | | men. Women with normal lipid levels are also more |
| and right coronary artery but the total calcium score is | | | | likely to experience angina/myocardial infarction than |
| most important. The EBCT can detect miniscule | | | | men. The standard lipid profile does not always |
| calcium deposits which is what is usually present with | | | | adequately reflect a woman's cardiovascular risk. A |
| early coronary artery disease. The presence of any | | | | study of asymptomatic women over 55 years of age |
| coronary calcification signifies coronary artery disease. | | | | with normal lipid levels found elevated coronary artery |
| People with low total calcium scores are at a lower | | | | calcium score. This is an area that needs to be |
| cardiovascular risk than high scores. | | | | evaluated further but suggests that coronary artery |
| Calcium scores range from zero (no plaque) to | | | | calcium scores may prove to be very beneficial in |
| several thousand (extensive plaque) and is a unitless | | | | assessing cardiovascular risk profiles in women. |
| measurement calculated for the entire coronary | | | | Indications for Coronary Artery Calcium Scans: |
| system. A calcium score of zero indicates the | | | | 1. Family history heart disease (especially premature |
| absence of any calcium and an extremely low | | | | heart disease) |
| likelihood of obstructive coronary artery disease. A | | | | 2. History of smoking |
| calcium score greater than 400 signifies extensive | | | | 3. Hypertension |
| calcification and a high likelihood of significant coronary | | | | 4. Obesity |
| artery disease. (See Average Calcium Score Chart) | | | | 5. Elevated lipid levels |
| These people should undergo further evaluation with | | | | 6. Diabetes |
| exercise stress test or nuclear stress test for | | | | 7. Men over 40 years old or postmenopausal women |
| myocardial ischemia. The higher the total score the | | | | 8. Young people with atypical symptoms |
| greater the overall plaque burden. Asymptomatic | | | | Contraindications for Coronary Artery Calcium Scans: |
| people with an intermediate calcium score require a | | | | 1. Known coronary artery disease |
| thorough risk assessment and individualized risk factor | | | | 2. People over 70 years old (little clinical benefit) |
| modification. A person's age and gender also need to | | | | 3. Pregnant women |
| be considered when evaluating the calcium score | | | | 4. |
| results. A calcium score of 175 may be average for a | | | | |