Coronary Disease in Emergency Department Chest Pain Patients with Recent Negative Stress Testing

BACKGROUND Cardiac stress tests for diagnosis of coronary artery disease (CAD) are incompletely sensitive and specific. OBJECTIVE We examined the frequency of significant CAD in patients presenting to the emergency department (ED) with chest pain who have had a recent negative or inconclusive (<85% of predicted maximum heart rate) cardiac stress test. METHODS This was a retrospective chart review of patients identified from ED and cardiology registries at the study hospital. We included patients presenting to the ED with a chief complaint of chest pain, with a negative cardiac stress test in the past three years as the last cardiac test, and hospital admission. One-hundred sixty-four patients met the inclusion criteria. Their admission was reviewed for diagnosis of CAD by positive serum troponin, percutaneous coronary intervention, or positive stress test while an inpatient. RESULTS Of 164 patients, 122(74.4%, 95% CI 67.7, 81.1) had a negative stress test prior to the index admission, while 42 (25.6%, 95% CI 18.9, 32.3) had otherwise normal but inconclusive stress tests. Thirty-four (20.7%, 95% CI 14.4,27.0) of the included patients were determined to have CAD. Twenty-five of the 122 patients (20.5%, 95% CI 13.3, 27.7) had negative pre-admission stress tests and nine of 42 patients (21.4%, 95% CI 9.0, 33.8) had inclusive stress tests of CAD. A statistical comparison between these two proportions showed no significant difference (p = .973). CONCLUSION Due to inadequate sensitivity, negative non-invasive cardiac stress tests should not be used to rule out CAD. Patients with negative stress tests are just as likely to have CAD as patients with inconclusive stress tests.