Contributions of nuclear cardiology to prognosis and risk stratification in coronary artery disease

Myocardial perfusion imaging in patients with suspected or known coronary artery disease and stable symptoms enables not only accurate diagnosis of disease but also entails prognostic value. Myocardial perfusion SPECT contributes to assessment of future cardiac events independently of other clinical parameters. A normal stress myocardial perfusion scan is associated with a favorable prognosis in all pre-test risk subsets similar to that of the general population independent of history, symptoms, and exercise electrocardiography test variables. Cardiac risk and benefit from invasive therapeutic strategies increase in relation to the severity of the abnormality of perfusion and function assessed by gated myocardial perfusion SPECT. Thus, stress myocardial perfusion imaging may serve as a gatekeeper for referral to coronary angiography enabling effective risk stratification in patients with suspected or documented coronary artery disease. In severe coronary artery disease accompanied by left ventricular dysfunction preoperative prediction of reversibility of functional impairment and improvement in survival after revascularization can be achieved by viability testing using nuclear cardiology. Absence of viability is associated with no significant difference in functional and survival outcomes, irrespective of treatment strategy. Therefore, unnecessary revascularization can be avoided in cases with absent evidence of viability. (orig.)