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