Choosing the appropriate stress modality. A clinical cardiologist's perspective

Pharmacological stress agents for evaluation of ischemic heart disease

Ischemic heart disease is the leading cause of death in the developed countries for those older than 65 years of age. In patients suspected to have coronary artery disease a stress test should be performed to identify the vulnerability of the myocardium to ischemia. As a rule of thumb, the evaluation of coronary artery disease is best done by exercise stress test. In patients who are not able to exercise adequately, pharmacological stress agents are used. The commonly used agents are the coronary vasodilators, adenosine and dipyridamole and the catecholamines, dobutamine and arbutamine. These agents are combined with imaging techniques to increase the sensitivity and specificity of the test. These agents have been widely used and have an excellent safety profile. Another advantage in using pharmacological stress agents is that they do not affect the image quality, especially with echocardiography and magnetic resonance imaging. Ongoing developments hold promise for safer and more reliable pharmacological stress agents in the future.

Predicting plaque rupture: enhancing diagnosis and clinical decision-making in coronary artery disease

Atherosclerosis is the process underlying coronary artery disease, myocardial infarction and cerebrovascular disease and is a leading cause of morbidity and mortality in industrialized countries. The atherosclerotic plaque is often indolent and progressive and may destabilize without warning. Components of the atherosclerotic plaque, including structural, cellular and molecular characteristics, determine its vulnerability to rupture. The imaging techniques currently available utilize invasive and non-invasive methods to characterize coronary artery stenoses. Detection, however, usually occurs late in the course of disease after symptoms have presented. Much effort has recently been directed at early detection and in defining markers of atherosclerotic disease. Our challenge for the future is to find non-invasive imaging modalities that can predict plaque vulnerability before irreversible damage has occurred. Through early detection and a targeted treatment strategy we hope to reduce the burden of ischemic heart disease.

Cost-effectiveness of stress echocardiography and nuclear perfusion imaging

Cost-effectiveness analysis is a method of comparing societal economic value of 2 different strategies. Ideally, it defines accurate test-related (direct and downstream) costs and appropriately converts differential patient outcomes into a dollar value. The likelihood that cost-effectiveness analysis translated into a policy-making tool will enhance health care and/or control costs is dependent on the validity of numerous assumptions about relative costs, patient outcomes, and generalizability of the literature to regional capabilities. The purpose of this report is to review the concept of cost-effectiveness analysis as it applies to stress echocardiography and stress myocardial perfusion imaging for selected patient subsets.