Abstract 16314: Stress Echocardiography is More Accurate for the Prediction of Coronary Artery Disease and with a Lower Cost to Diagnosis Compared to Exercise Electrocardiography in Patients with Recent Onset Suspected Cardiac Chest Pain
Background: Exercise ECG (ExECG) is widely used to assess patients with suspected coronary artery disease (CAD). However stress echocardiography (SE) is a well established alternative technique for the assessment of these patients. We hypothesised that SE, due to its greater accuracy and feasibility, may be superior to ExECG, in terms of positive predictive value and cost to diagnosis, when used as the initial test for the assessment of patients presenting with suspected cardiac chest pain.
Methods: Patients referred with recent onset chest pain during 2011, with no known history of CAD and with a pre-test likelihood of CAD greater than 10%, who underwent first line ExECG or SE were identified. The tests were classified as positive, negative or inconclusive for ischaemia. Coronary angiography (CA) was performed, with the knowledge of the functional test results, as indicated clinically. CAD was defined as the presence of >50% stenosis in at least one major epicardial vessel on CA. Cost to diagnosis of CAD was determined for each functional test by adding the initial cost of the test to the cost of subsequent tests leading to and including CA.
Results: We identified 462 patients who underwent ExECG (230(49.8%) negative, 94 (20.3%) positive, 138 (29.9% inconclusive) and 240 who underwent SE (198 (82.5%) negative, 35 (14.6%) positive, 7 (2.9%) inconclusive) as first line. The mean pre-test probability of CAD was 43±26% vs 51±28% respectively. Of the 91 patients referred for CA on the basis of ExECG, CAD was present in 38 (42%) which was significantly (p=0.01) lower than in the SE group which predicted CAD in 22 out of 33 patients referred for CA (67%). The mean cost to diagnosis was £408 for the ExECG versus £345 for the SE group (p<0.01).
Conclusions: In a population with intermediate pre-test probability of CAD, SE was more accurate for predicting the presence of CAD with a lower cost to diagnosis compared to ExECG. This study suggests that SE rather than ExECG should be the initial test for the assessment of suspected CAD in this population.
- © 2012 by American Heart Association, Inc.