Abstract 13703: Initial Stress Echocardiography is Superior for the Prediction of Coronary Artery Disease and Outcome and is More Cost-Effective than Initial Exercise Electrocardiography in Patients With Suspected Angina and no Known Coronary Artery Disease
Background: Exercise ECG (ExECG) is recommended as the initial test in patients with suspected coronary artery disease (CAD). Stress echocardiography (SE) is however more accurate, 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 predicting CAD, outcome and cost-effectiveness, when used as first line in patients presenting with suspected angina without known CAD.
Methods: Patients seen in 2011, with chest pain, no known history of CAD, a pre-test likelihood of CAD of >10%, who underwent SE or ExECG as first line were identified. Results of SE/ExECG were classified as positive (+ve), negative (-ve) or inconclusive (inc) for ischaemia. Decision to request coronary angiography (CA) was taken by the treating physician following the initial test results. Cost to diagnosis of CAD( >50% stenosis in at least one major epicardial vessel )was determined by adding the cost of the initial test to the cost of any subsequent tests leading to and including CA on an intention to treat basis. Follow-up data on hard cardiac events (death and acute myocardial infarction) were obtained 18 months after the presentation of the last study patient.
Results: A total of 456 patients underwent ExECG (224 (49%) -ve, 93 (20%) +ve, 139 (31%) inc) and 241 underwent SE (200 (83%) -ve, 35 (15%) +ve, 6 (2%) inc) as first line. Of 93 patients with +ve ExECG, 76 underwent CA, with CAD present in 36 (47%) which was significantly (p=0.03), lower than in the +ve SE group which predicted CAD in 23 out of 33 patients (70%). Mean cost to diagnosis was £458 for the ExECG versus £374 for the SE group (p=0.01). Over a follow-up period of 22±4 months, there were no cardiac deaths. There was no significant difference (p=0.9) in cardiac event rate between -ve ExECG (5(2%) and -ve SE(4(2%). Cardiac events were however significantly (p=0.02) higher in the +ve SE (2(6%) vs +ve ExECG (0%) despite similar revascularisation rate between the two groups(29/93 (31%) for +veExECG vs 14/35 (40%) for +veSE, p=0.3).
Conclusions: SE predicted CAD with higher accuracy and identified a higher risk population with superior cost benefit compared to ExECG, in patients with intermediate pre-test probability of CAD, when used as first line.
- © 2013 by American Heart Association, Inc.