Screening tools for coronary artery disease (CAD) in asymptomatic subjects: the role of stress testing

Coronary risk assessment in asymptomatic subjects is an important issue in primary care. Global coronary risk assessment has been incorporated in recent guidelines (www.agla.ch) and clearly defines, which step should be taken in relation to risk stratification obtained from coronary risk charts. However, silent myocardial ischaemia is encountered quite frequently and such subjects probably are at higher risk than derived from coronary risk charts. Silent ischaemia can be detected by several methods: exercise electrocardiogram (ECG), stress imaging studies (stress echocardiography, stress myocardial perfusion SPECT, stress myocardial perfusion PET, stress magnetic resonance) or Holter monitoring. Increasing evidence suggests that coronary revascularisation of asymptomatic ischaemia with known CAD improves prognosis, however, in primary care subjects with silent ischaemia and under optimal medical treatment, revascularisation does not improve outcome. In the future it may prove to be important to define categories of asymptomatic patients who might nevertheless benefitf rom ischaemia testing. Numerous studies have shown that an aggressive medical therapy in asymptomatic subjects with high coronary risk reduces global plaque burden, myocardial ischaemia and coronary events. "Negative" ischaemia tests in the setting of high coronary risk may even deter primary care physicians from aggressive primary prevention. Therefore, at the moment, ischaemia tests are neither recommended in asymptomatic primary care patients nor in the general population; but adherence to preventive guidelines is fundamentally important to reduce the epidemic of coronary artery disease.