Prof. Gibbons started off the session by pointing out that screening of asymptomatic patients for disease is an important public health issue. The Framingham risk score can be used to identify high risk patients (ten year risk of cardiac death or myocardial infaction >20%).
Diabetics are at high risk regardless of whether or not other risk factors are present. Calcium scoring may add incremental value. A key concept is that screening should result in the potential benefit of reducing cardiac death or myocardial infarction. He emphasised that, unfortunately, none of our current tests has been proven to improve compliance or outcomes.
Prof. Achenbach pointed out that coronary CT angiography (CTA) is highly accurate in detecting high grade coronary artery stenoses. However, the patients who have had acute myocardial infarction are not the ones with the highest amount of overall plaque, but the ones with more non-calcified plaque. Imaging non-calcified plaque is difficult and there is high inter-observer variability. There is significant radiation burden (about 10 mSv) and the patient must be given contrast. All of the current data on the value of CTA is retrospective. There is no data on the prognostic value of quantifying non-calcified plaque. Therefore, he does not recommend screening asymptomatic patients with CTA.
Prof. Wackers addressed the issue of diabetics who are asymptomatic. Recent prospective studies have shown that the prevalence of abnormal myocardial perfusion in these patients is less than had been previously thought but is still significant. In the DIAD study, which will finish next year, 22% of totally asymptomatic diabetic patients had evidence of occlusive coronary artery disease on myocardial perfusion imaging. The presence or absence of other risk factors did not predict perfusion abnormalities. Calcium scoring may be helpful in choosing which patients are most appropriate to screen.
Prof. Poldermans discussed pre-operative risk stratification strategies. The standard risk scores are not helpful in asymptomatic patients. Peri-operative myocardial infarction does not correlate with extent of occlusive coronary artery disease but is caused by plaque rupture and thrombus formation. The highest risk patients are those that are undergoing vascular surgery. These patients require a thorough clinical risk assessment. He believes that giving perioperative cardioprotectors such as statins, beta blockers and aspirin is more helpful than doing any screening tests. It is most important to control heart rate peri-operatively.