Outcome of patients with a final diagnosis of chest pain of undetermined origin admitted under the suspicion of acute coronary syndrome

Abstract

Study objectives

Patients presenting to the emergency department (ED) with chest pain after a recent negative inpatient evaluation for cardiac pathology represent a dilemma for the emergency physician. The purposes of this study were to assess the outcome of patients discharged with a diagnosis of chest pain of undetermined origin and to identify predisposing factors for further cardiac events.

Methods

The resources of the Rochester Epidemiology Project were used to identify all admitted ED patients with chest pain with suspected acute coronary syndrome who received a discharge diagnosis of chest pain of undetermined origin from 1985 through 1992. Patient records were reviewed for the occurrence of adverse cardiac events and subsequent ED visits for recurrent chest pain within 12 months of discharge. Associations between patient characteristics and an adverse cardiac event were evaluated univariately and summarized by using odds ratios (ORs). Long-term mortality was also determined.

Results

Among 1,973 admitted ED patients with chest pain, 230 were given a diagnosis of chest pain of undetermined origin. Ten (4.4%) of 230 patients experienced an adverse cardiac event. Factors significantly associated with an adverse cardiac event included an abnormal ECG on admission (OR 9.5; 95% confidence interval [CI] 2.0 to 45.8), preexisting diabetes mellitus (OR 7.1; 95% CI 1.8 to 27.2), and preexisting coronary artery disease (OR 28.4; 95% CI 3.5 to 229.0). Thirty-three (14%) patients returned to the ED within 12 months of discharge; 5 patients were given a diagnosis of a cardiac condition, and 5 were given a diagnosis of a gastrointestinal condition. In long-term follow-up, 46 patients died, with a mean time from hospital discharge to death of any cause of 6.1 years and an estimated 5-year survival of 91.4%.

Conclusion

Among patients discharged from the hospital with a diagnosis of chest pain of undetermined origin, those with an initial abnormal ECG, preexisting diabetes, or preexisting coronary artery disease are at higher risk of a subsequent adverse cardiac event. In the absence of such factors, cardiac outcome is excellent.

Introduction

Noncardiac chest pain is a common dilemma in the emergency department (ED) that is expensive to manage and poses diagnostic and treatment challenges.¹ Among the millions of Americans who undergo cardiac catheterization each year because of chest pain, a recent study found that 19% of patients had no arteriographic evidence of symptomatic coronary artery disease.2, 3 The outcome of patients with a diagnosis of noncardiac chest pain is controversial. Studies have shown that patients with normal coronary angiography have a low cardiac mortality and morbidity,4, 5, 6 whereas others have concluded that patients admitted with chest pain of apparently noncoronary origin are at a higher risk for later cardiac death.7, 8, 9 Morbidity, particularly psychological morbidity, is high, and despite the report of a normal coronary angiogram, short- and long-term follow-up studies have demonstrated that 34% to 70% continue to have chest pain, excessively use medical services, have repeated hospitalization and ED visits, and report functional and social disabilities.10, 11, 12, 13, 14, 15, 16

The causes of noncardiac chest pain are diverse and overlapping. An esophageal source of noncardiac chest pain is reported in up to 60% of cases, and gastroesophageal reflux disease is probably the most important cause.17, 18, 19, 20 Many of these patients have panic disorder, obsessive-compulsive disorder, major depressive episodes, and musculoskeletal disorders.21, 22, 23 Recently, it has been recognized that a proportion of patients dismissed with the diagnosis of noncardiac chest pain might have impaired regulation of coronary vasomotor tone, altering their ability to maintain coronary blood flow at rest or during stress.24, 25, 26, 27, 28, 29, 30 Noncardiac chest pain refers to the entire spectrum of patients with nonacute coronary syndrome chest pain under investigation. On confirmation of gastrointestinal, psychiatric, pulmonary, or other definitive diagnosis of chest pain, there remains a subgroup of patients with chest pain of undetermined origin.¹

Patients who present to the ED with chest pain and a recent negative inpatient evaluation for cardiac pathology represent a diagnostic, therapeutic, and dispositional dilemma for the emergency physician. Little is known about the outcome and the incidence of adverse cardiac events in this patient population. Risk factors able to predict adverse cardiac events have not been identified. Using a sample of patients discharged from the hospital with a diagnosis of chest pain of undetermined origin, the purposes of this study were to (1) assess adverse cardiac events within 12 months of discharge, (2) determine long-term mortality, and (3) identify predisposing factors increasing the likelihood of the occurrence of an adverse cardiac event.