Original contribution
Predicting Adverse Outcomes in Syncope

Presented at the Society for Academic Emergency Medicine National Meeting, New York, NY, May 2005, and at the Society for Academic Emergency Medicine New England Regional Meeting, Shrewsbury MA, April 2005.
https://doi.org/10.1016/j.jemermed.2007.04.001Get rights and content

Abstract

Syncope is a common presentation to the Emergency Department (ED); however, appropriate management and indications for hospitalization remain an ongoing challenge. The objective of this study was to determine if a predefined decision rule could accurately identify patients with syncope likely to have an adverse outcome or critical intervention. A prospective, observational, cohort study was conducted of consecutive ED patients aged 18 years or older presenting with syncope. A clinical decision rule was developed a priori to identify patients at risk if they met any of the following 8 criteria: 1) Signs and symptoms of acute coronary syndrome; 2) Signs of conduction disease; 3) Worrisome cardiac history; 4) Valvular heart disease by history or physical examination; 5) Family history of sudden death; 6) Persistent abnormal vital signs in the ED; 7) Volume depletion; 8) Primary central nervous system event. The primary outcome was either a critical intervention or an adverse outcome within 30 days. Among 362 patients enrolled with syncope, 293 (81%) patients completed their 30-day follow-up. Of these, 201 (69%) were admitted. There were 68 patients (23%) who had either a critical intervention or adverse outcome. The rule identified 66/68 patients who met the outcome for a sensitivity of 97% (95% confidence interval 93–100%) and specificity of 62% (56–69%). This pathway may be useful in identifying patients with syncope who are likely to have adverse outcome or critical interventions. Implementation and multicenter validation is needed before widespread application.

Introduction

Syncope is a common presentation to the Emergency Department (ED), however, a universally applied approach to appropriate management and criteria for hospitalization is lacking. Syncope accounts for approximately 1–3% of all ED visits and up to 6% of all hospital admissions nationwide (1, 2). The cost of care per hospital admission has been estimated at roughly $5300 per stay, for a total cost of over $2 billion per year nationally (1, 2, 3, 4, 5, 6, 7).

The ED workup of syncope centers on several goals. First, the Emergency Physician (EP) must identify those patients with life-threatening causes requiring immediate treatment. Second, the EP must identify those who would benefit from specific treatment or intervention. Third, the EP must identify those who remain without a diagnosis, despite appropriate workup, and who will require further evaluation. Central to this final goal is the determination of the appropriate setting for such evaluation, inpatient vs. outpatient (6). Despite these clear objectives, the ED evaluation of syncope is challenging. The differential diagnosis of syncope ranges from benign to immediately life-threatening conditions. Patients presenting to the ED with a complaint of syncope are often asymptomatic and well-appearing on arrival. Despite thorough evaluation, a cause is not established in 38–47% of cases (1, 7, 8). This presents a challenge to EPs as syncope patients are at risk for significant dysrhythmia and sudden death and could be among the well-appearing group (9). This concern is the impetus behind a great deal of research to assist the EP in identifying those patients at risk for cardiac mortality and significant dysrhythmia; and, ultimately deciding who should be admitted to the hospital for further evaluation and who is safe for discharge. Recommendations for hospital admission should be based on the potential for adverse outcomes if further evaluation and workup is delayed (10).

We, therefore, developed a clinical decision rule with the intent of validating it as the basis for this study (Table 1). This rule was designed by using criteria extracted primarily from the American College of Emergency Physicians’ (ACEP) clinical policy and recommendations of the San Francisco Syncope Rule as well as the clinical acumen of a group of expert emergency physicians, cardiologists, electrophysiologists, and internists (12, 13, 14). The objective of this study was to determine if our decision rule could accurately discriminate patients with syncope likely to have a critical intervention or adverse outcome. Ultimately, our goal is to enable the emergency practitioner to better discriminate syncope patients who require hospitalization from those who may be safely discharged home from the ED. We hope to ensure that no patient with a possible life-threatening etiology of syncope is discharged home, and at the same time institute a more judicious approach in deciding which patients require hospital admission for syncope.

Section snippets

Study Design and Setting

We conducted a prospective, observational, cohort study of consecutive patients presenting with syncope 24 h a day, 7 days a week between September 2003 and April 2004. All patients presented to the ED of a large urban teaching hospital with an annual ED census of 48,000 visits. Institutional review board (IRB) approval was received before initiation of the study.

Syncope was defined as a sudden and transient (< 5 min) loss of consciousness, producing a brief period of unresponsiveness and a

Results

There were 384 patients who had syncope and met inclusion criteria, 362 (94%) of whom were included in the study. There were 293/362 (81%) patients who completed their 30-day follow-up and were included in the analysis. Of patients lost to 30-day follow-up, admission rates and rates of adverse outcomes in the ED and during hospitalization were similar to those of patients who remained in the study. A total of 201/293 (69%) patients were admitted, with 56 outcomes occurring during

Discussion

This study suggests that the Boston Syncope Rule may be helpful in accurately identifying ED patients at risk for adverse outcomes. Utilizing our risk factors to screen syncope patients yielded a sensitivity of 97%, specificity of 62%, with a negative predictive value of 99%. In this population, admitting only those patients identified by the decision rule admissions would have led to a 48% reduction in hospital admissions. Clearly, in an overburdened health care system, the ability to safely

Limitations

There are a number of limitations of this study, including use of a single testing site, small sample size, and lack of long-term follow-up. The 19% of patients who were lost to 30-day follow-up may have caused us to underestimate the true number of adverse events and critical outcomes. If this were the case, then our estimates of the accuracy and safety of our rule may be overestimated. A total of 25 risk factors are a large number to remember, however, they can be shortened to the eight

Conclusion

In summary, despite careful history and physical examination, the EP can be assisted in discerning both etiology and, more importantly, outcome in syncope. Our syncope pathway may be useful in guiding the EP by helping to identify which patients are likely to have adverse outcomes or the need for critical interventions. Ultimately, this rule may significantly reduce hospital admissions and serve as a vehicle to contain both rising medical costs and adverse outcomes associated with unnecessary

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      Prognostic scores used to risk stratify syncope patients in the ED have not been widely adopted, however; there are risk factors that have consistently been identified as predictors of adverse outcomes. These include older age (>60 years) (19–21), male sex (21–25), and severe structural or coronary heart disease (heart failure, low left ventricular ejection fraction, or previous myocardial infarction) (10,19,21,24–33). A higher prevalence of these risk factors was found among admitted patients in a multicenter Italian study of patients presenting to the ED compared with risk factors in those who were discharged (27).

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