Coronary artery disease (CAD) is a process in which plaque builds up inside the coronary arteries of the heart. This plaque, called atherosclerosis, can narrow the arteries, depriving the heart of oxygen, which in turn causes chest pain. Initially this plaque is soft and waxy in consistency, but over time the plaque will scar and calcify. A heart attack occurs when a soft “vulnerable” plaque ruptures, causing the sudden formation of a blood clot. CAD is the leading cause of death in the United States for both men and women. According to Dr. Steven Nissen of Cleveland Clinic, “the rupture of a soft plaque will be the cause of death of about half of us in the United States.”
The major risk factors for CAD include smoking, high blood pressure, elevated cholesterol, obesity, diabetes and family history of heart disease. These traditional risk factors provide an incomplete picture of who is at risk for cardiovascular disease; furthermore, 50% of patients who have a heart attack will have normal cholesterol levels.
Until recently the two main imaging tests to evaluate CAD were cardiac catherization, which requires threading a catheter from an artery in the groin to the arteries of the heart, and nuclear medicine heart study. Jefferson City Medical Group (JCMG) Radiology department is proud to be the first to bring two new state-of-the-art cardiac imaging tests to Jefferson City: CT (computer tomography) angiography of the Coronary Arteries and CT Coronary Calcium Scoring.
Cardiac catherization is the imaging study of choice for patients presenting with chest pain and EKG evidence of a heart attack. Patients with chest pain and a normal EKG are typically imaged with a nuclear medicine heart study. The nuclear test is a functional test for which a significant coronary artery blockage must be present in order to detect decrease blood flow to the heart. Furthermore, the nuclear test does not directly image the coronary arteries. A negative nuclear medicine test does exclude the presence of severe CAD; however, a negative test does not exclude the presence of early CAD. Detection of early preclinical CAD is imperative so that aggressive life style modifications and medical management can be initiated and thus prevent progression to severe symptomatic CAD.
Coronary computed tomography angiography (CCTA) is a non-invasive imaging test that provides very lifelike anatomic pictures of the heart. CCTA is recommended for patients presenting with chest pain with a low to intermediate risk for CAD. The test is fast, relatively inexpensive and requires less radiation than a nuclear medicine heart test. Not only are the lumens of the coronary arteries visualized, but also the vessel walls where atherosclerotic plaques are found. Of the above tests mentioned, only CCTA can characterize plaque as soft or calcified. No other test does a better job at quantifying mild or moderate CAD. Moreover, a negative coronary artery CTA essentially excludes coronary artery disease as an etiology for the patient’s chest pain.
During a CCTA scan intravenous contrast (dye) is given. In addition, patients may need to be given oral and/or intravenous medicine prior to the test for heart rate control. Reimbursement is approved by Medicare and most insurance providers.
CT Coronary Calcium Scoring is a non-invasive test to determine the presence, location and extent of calcified plaque in the coronary arteries. The test is extremely fast and no intravenous contrast is required. The presence of this calcified plaque signals the presence of atherosclerosis and thus coronary artery disease (CAD). Because calcium is a marker of CAD, the amount of calcium detected on a cardiac CT scan is a helpful prognostic tool and is expressed as a calcium score. The higher your score is, the higher your risk for a cardiovascular disease. Calcium scoring is a screening test recommended for asymptomatic patients with risk factors for CAD. Calcium scoring is not covered by most insurance providers, but can be performed on self-pay basis for a nominal fee. Are you at risk? What is your heart score?