Impact of clinical predictors and routine coronary artery disease testing on outcome of patients admitted to chest pain decision unit

Abstract

Background: Chest pain decision unit (CDU) evaluation of patients with acute chest pain (ACP) and nondiagnostic electrocardiogram (ECG) usually includes noninvasive testing for coronary artery disease (CAD).

Hypothesis: CAD evaluation will not improve clinical outcome in low-risk ACP patients.

Methods: We studied 459 adults admitted to CDU with ACP and no troponin release who underwent noninvasive CAD testing (stress testing in 396 and coronary computed tomographic angiography in 63). Multivariate logistic regression was used to determine predictors of adverse outcome over a 3-year follow-up period.

Results: Initial noninvasive test was normal in 367 (80%) and abnormal (positive or indeterminate) in 92 (20%). A total of 42 (9%) patients underwent invasive coronary angiography, and 16 (3.5%) underwent revascularization. During follow-up, 33 patients had a total of 36 major clinical events: 12 revascularizations, 9 myocardial infarctions, and 15 deaths. Multivariate logistic regression analysis identified abnormal ECG (odds ratio [OR]: 2.7, P = 0.03), typical chest pain (OR: 3.8, P = 0.002), diabetes (OR: 4.1, P = 0.001), and known CAD (OR: 2.3, P = 0.03) as independent predictors for adverse outcome, but not noninvasive test result. Thus, in 187 patients with no high-risk features (41% of the cohort), the annualized event rate was 0.5%. In 272 patients with at least 1 high-risk feature, annualized event rates were 2.8% and 5.7% when noninvasive test was normal or abnormal, respectively (P = 0.04).

Conclusions: Clinical risk stratification allows identification of patients at low risk of adverse outcome over an intermediate period of follow-up. Noninvasive testing is not warranted in such patients.

Figure 1

Flowchart demonstrating the clinical and diagnostic algorithm followed in 612 patients with acute chest pain evaluated over a 1‐year period. Abbreviations: CABG, coronary artery bypass graft surgery; CAD, coronary artery disease; CCTA, coronary computed tomographic angiography; CDU, chest pain decision unit; DSE, dobutamine stress echocardiography; ESE, exercise stress echocardiography; MPI, myocardial perfusion imaging; PCI, percutaneous coronary intervention.

Figure 2

Flowchart demonstrating the results of noninvasive testing, chest pain decision unit disposition, and follow‐up of 187 patients with acute chest pain and low likelihood of coronary etiology. *One myocardial infraction, 1 revascularization, and 1 death. Abbreviations: CAD, coronary artery disease; ECG, electrocardiogram.