New calcium tests are understood to be able to accurately determine if a patient needs to be prescribed anticholesterol drugs known as statins, which work well but often produce dramatic side effects. This new test using a CT scanner in tandem provides insight into the likelihood that certain patients at moderate risk of heart problems will have a heart attack or stroke.
The new study released this week sought to determine whether a test of calcium in the arteries is more helpful at estimating risk than a blood test that examines levels of C-reactive protein.
The researchers tracked 2,083 people for six years. They found that 13% of those with the highest levels of calcium in their arteries had a heart attack or stroke during that time period. But just 2% of those with high levels of C-reactive protein, and no calcium buildup, had a heart attack or stroke.
Not everyone needs a calcium test, said lead study author Dr. Michael J. Blaha, a cardiology fellow at the Johns Hopkins University School of Medicine:
"We believe looking for calcification in coronary vessels in certain patients makes sense in order to predict who may benefit from statin therapy, because the test gets right to the heart of the disease we want to treat."
The main intent of the test is for people who fall into the middle area between those who are at high risk of heart problems due to factors like high blood pressure and those who are at low risk.
Dr. Roger Blumenthal, director of the Ciccarone Center for the Prevention of Heart Disease at Johns Hopkins University continues:
"Our data support recent American Heart Association guidelines, which say it is reasonable to order a coronary calcium scan for adults who are considered to be at intermediate risk of a heart attack over the next 10 years. A high coronary calcium score would indicate that statin therapy would likely be a useful strategy to lower that person's cardiovascular risk."
A blood calcium test is usually ordered to screen for, diagnose, and monitor a range of conditions relating to the bones, heart, nerves, kidneys, and teeth. Blood calcium levels do not directly tell how much calcium is in the bones, but rather, how much calcium is circulating in the blood.
A total calcium level is often measured as part of a routine health screening. It is included in the Comprehensive Metabolic Panel (CMP) and the Basic Metabolic Panel (BMP), groups of tests that are performed together to diagnose or monitor a variety of conditions. When an abnormal total calcium result is obtained, it is viewed as an indicator of an underlying problem. To help diagnose the underlying problem, additional tests are often done to measure ionized calcium, urine calcium, phosphorous, magnesium, vitamin D, and parathyroid hormone (PTH). PTH and vitamin D are responsible for maintaining calcium concentrations in the blood within a narrow range of values.
Measuring calcium and PTH together can help determine whether the parathyroid glands are functioning normally. Measuring urine calcium can help determine whether the kidneys are excreting the proper amount of calcium and testing for vitamin D, phosphorus, and/or magnesium can help determine whether other deficiencies or excesses exist. Frequently, the balance among these different substances, and the changes in them, are just as important as the concentrations.
Cardiologist Dr. Vijay Nambi, an assistant professor at Baylor College of Medicine, said that most insurance companies feel that these tests can help patients make their own decisions about the direction of treatment although these are often not covered by insurance companies:
"Sometimes people have to pay for it out of pocket. It helps physicians in a lot of respects."
The test can cost up to five hundred dollars.
Written by Sy Kraft