New Surrogate Markers for Coronary Heart Disease

Accessible online at: www.karger.com/journals/hed Atherosclerosis develops in many vascular domains, but varies in severity from one vascular bed to another in the same individual. Most often, the aorta is the seat of the most advanced changes, but clinical disease is of course linked mainly to atherosclerosis occurring in the coronary arteries, the extracranial arteries to the brain and the arteries to the lower extremities. Subclinical atherosclerosis can be detected as intima-media thickening (IMT), as demonstrated in the report of Sramek et al. [1] in the present issue of Heart Drug and in many other publications. The purpose of the study of Sramek et al. [1] was to determine whether IMT in the femoral artery as compared to IMT in the carotid artery might be a valid surrogate for the detection of coronary artery disease (CAD). The main finding was that IMT in the common femoral artery was more closely associated with CAD than IMT in the carotid artery. Intuitively, the finding is not surprising, as combined disease occurs frequently. While this finding may represent a refinement of the present methodology, the study populations, especially the control sample, were small and highly selected, and the finding needs to be confirmed in larger, prospective series. The gold standard for CAD is coronary arteriography. Noninvasive markers have been used in clinical medicine for many decades for the diagnosis of CAD. These markers, i.e. exercise electrocardiography, radionuclide myocardial scintigraphy and various applications of echocardiography, belong to the core of clinical cardiology. Their application and interpretation as well as their limitations are exceedingly well described in the cardiological literature. At the other end of the spectrum stands risk factor assessment based on coronary risk factors such as elevated serum cholesterol, elevated blood pressure, cigarette smoking and many others. These risk factors have been validated time and again in prospective epidemiological studies, the prime example being the Framingham study [2]. Furthermore, risk factor reduction by appropriate treatment has conclusively been shown to reduce the incidence of clinical coronary heart disease [3, 4]. Clinical cardiology has increasingly moved towards the preventive aspects, and in particular what might be termed intermediate prevention, that is, the prevention of progression from high-risk and subclinical disease to clinically apparent heart disease. The occurrence of high-risk or subclinical disease triggers the application of risk reduction, in particular lipid-lowering therapy, aggressive antihypertensive treatment and behavioral modification with regard to smoking, obesity and physical exertion. In this context, three ‘new’ surrogate markers for CAD are extremely interesting. The demonstration of calcium deposits in coronary arteries by electron beam tomography (EBT) has been shown to correlate well with the presence of obstructive CAD and the clinical prognosis [5, 6]. What is not known is whether preventive treatment based on the findings of EBT may in fact reduce the subsequent occurrence of clin-