Objective: In patients with acute chest pain and normal range cardiac troponin (cTn), accurate risk stratification for acute coronary syndrome is challenging. This study assesses the incremental value of stress testing to identify patients for angiography with a view to revascularisation.
Methods: A single-centre observational study recruited patients with acute chest pain in whom serial cTn tests were negative and stress testing (exercise tolerance testing/dobutamine stress echocardiography) was performed. Stress tests were reported as negative, non-diagnostic or positive. The primary outcomes were revascularisation on index admission, or cardiac death and myocardial infarction over 1 year follow-up.
Results: Of 749 patients recruited, 709 underwent exercise tolerance testing and 40 dobutamine stress echo of which 548 (73.2%) were negative, 169 (22.6%) were non-diagnostic and 32 (4.3%) were positive. Patients with positive tests (n=19 (59.4%)) were more likely to undergo index admission revascularisation than patients with non-diagnostic (n=15 (8.9%)) (p<0.001) tests who in turn were more likely undergo index admission revascularisation than those with negative tests (n=2 (0.4%)) (p<0.001). The risks of adverse events including cardiovascular death/acute myocardial infarction were low and were similar across stress test outcomes.
Conclusions: The incremental value of stress testing was the identification of an additional 34 (4.5% (95% CI 3.0% to 6.0%)) patients who underwent index admission revascularisation with a view to preventing future adverse events. Uncertainty in whether revascularisation prevents adverse events in patients with negative cTn means the choice to undertake stress testing depends on whether clinicians perceive value in identifying 4.5% of these patients for revascularisation.
Clinical trial registrations: ACTRN1260900028327, ACTRN12611001069943.
Keywords: cardiac care, acute coronary syndrome; cardiac care, acute myocardal infarct; cardiac care, diagnosis.
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