Author + information
- C. Richard Conti, MD∗ ()
- ↵∗Health Science Center, University of Florida, Room M-438, 1600 SW Archer Road, P.O. Box 100277, Gainesville, Florida 32610-0277
Because I am a clinical cardiologist with a major interest in ischemic heart disease, this elegantly written and comprehensive assessment of coronary artery calcium scanning attracted my attention.
I do not think anyone would argue that the presence of calcium in the coronary artery equals coronary atherosclerosis but does not define the degree of stenosis. At the moment, the blooming artifact makes it difficult to assess lumen size even when computed tomography (CT) angiography is done. Likewise, a properly done negative calcium scan does not equate with the absence of any plaques in the coronary circulation, for example, noncalcified plaques, which are also risk factors.
Those interested in this subject and working in this field believe that there is evidence suggesting that asymptomatic individuals with an “intermediate” Framingham Risk Score may be “‘reasonable candidates for using coronary artery calcification scanning as a potential means of modifying risk predictions and altering therapy.” Unfortunately, no risk score is useful clinically if there is no intervention that might alter the clinical outcome.
It is interesting to reflect on the historical aspects of the identification of coronary artery calcium. Many years ago, coronary artery calcium was reported using simple cine fluoroscopy. Unfortunately, the sensitivity of the fluoroscopic technique is less than the CT technique, and CT can quantitate the amount of calcium, whereas fluoroscopy cannot.
In this paper, Hecht (1) compares early detection of coronary artery calcium with the early detection of breast cancer, colon cancer, lung cancer, and aortic aneurysm. I do not think that this is a fair comparison because these 4 conditions, if detected early, can initiate immediate curative (or at least palliative) therapy. In contrast, early detection of coronary atherosclerosis by calcium scanning in a normotensive, nonsmoking, exercising, nondiabetic patient with normal lipid levels offers no advantage to the worried well because there is nothing to treat. In addition, the lack of insurance coverage for CT scanning can be a problem for several low-income patients.
I would like to propose a theoretical patient and ask what therapy should be recommended. The patient is a 55-year-old asymptomatic man who has mildly elevated blood pressure, moderately elevated cholesterol, moderately elevated low-density lipoprotein, and low high-density lipoprotein. This patient could be considered at intermediate risk by Framingham criteria (9% estimated risk at 10 years) and a finding of calcium in the coronaries would increase this risk (20% risk at 10 years), thus justifying aggressive medical management. I agree and cannot argue that point, but I think most cardiologists (including me) would be fairly aggressive with blood pressure management and lipid management in this particular patient whether or not coronary artery calcium is present.
I have no idea whether there is calcium in my coronary arteries (at age 80, there probably is) and if I did know, I am not sure what I would do about it other than what I am doing without knowing. I guess it would scare me a little, particularly if calcium was present in high concentration. However, I would also be concerned if I had uncontrolled hypertension, diabetes, obesity, renal disease, or severe hypercholesterolemia. I can do nothing about my age or my sex, so why worry about that?
Along with many others, I firmly believe that the presence of coronary artery calcium heightens the level of awareness of potential major adverse cardiac events, and it certainly should stimulate the physician and the patient to control other known clinical problems such as hypertension, smoking, diabetes, obesity, hyperlipidemia, lack of exercise, and so forth.
I am in full agreement with Hecht’s proposal that if the presence of calcium in the coronary artery can be used to motivate patients to adhere to a program of risk factor reduction, then patients with known risk factors should have a coronary artery calcium scan. If the scan does not motivate the patient, then I see no reason to do it. I guess one can do the scan and see what happens to patient adherence.
Please note: Dr. Conti has reported that he has no relationships relevant to the contents of this paper to disclose.
- American College of Cardiology Foundation