Adverse Cardiac Events in Emergency Department Patients with Chest Pain Six Months after a Negative Inpatient Evaluation for Acute Coronary Syndrome

Academic Emergency Medicine 2002 Vol 9, p 896-902.

Manini, et al.

Reviewed by David Wirtz

Methods

• Retrospective review of consecutive patients from 1/1/99 to 9/31/99; all patients admitted with ACS with a negative inhospital workup (admitted to tele, serial EKGs, and 16-24 hr serial CK-MB and Trop T enzymes) were included.
• The exclusion criteria were positive cardiac study, transfer, heart transplant, no residence, and resides outside of California.
• At Six months patients were contacted by telephone to document clinical cardiac events, admissions, or diagnostic procedures. Demographic and cardiac risk factor data were also gathered. (8% were lost to follow up).
• Patients were categorized into three groups according to whether they received a cardiac diagnostic test (exercise treadmill, angio, stress echo, or stress thallium perfusion scan): Inpatient Test (IT), Outpatient Test (OT), and No Test (N).

Outcome Measures

• Composite Endpoint of Adverse Cardiac Event (ACE) included MI, cardiac death, emergent revascularization, unstable angina, and cardiac arrest.
  • MI according to WHO definition  two of chest pain, EKG changes, and elevated enzymes
  • Unstable angina defined by angina at rest or increase in angina, ST changes during chest pain, or ischemic stress test or cardiac cath. This was included because the long term mortality is similar to that of MIs.

Data Analysis

• For nominal (categorical) variables, the data were summarized in percentages and chisquare statistics were used to assess group differences.
• Univariate analysis was first performed to identify potentially important baseline characteristics associated with the composite endpoint of ACEs at six months.
• Multivariate logistic regression models were developed through stepwise variable selection to assess the effect of diagnostic test setting and baseline clinical characteristics on the composite of ACEs at six months.
• All p-values were two-tailed with one degree of freedom. A p-value < 0.05 was considered significant.

Results

Overall, 78% (122/157) of the patients were scheduled to receive a diagnostic study as part of their evaluation for ACS. Overall, 103 patients were tested. In the OP group, 37% (19/52) of the patients were noncompliant and were not tested according to schedule.

TABLE 2  ACE after 6 months, all patients.

TABLE 3  ACEs after Six Months in Patients without Prior CAD

TABLE 4  Outpatient Diagnostic Test as a Predictor of Adverse Cardiac Events (ACEs) at Six Months^*