Correspondence

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American Journal of Emergency Medicine

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Performance of an outpatient Stress testing protocol for low risk chest pain patients presenting to the ED

Chest pain accounts for about 10% Emergency Department (ED) visits, and the majority of these patients are at low risk [1,2]. One guide- line-recommended treatment strategy is to discharge low risk patients with a plan for Outpatient stress testing within 72 h [3]. The purpose of our study was to determine patient adherence to an outpatient stress testing protocol, and to evaluate its efficacy in diagnosing treatable cor- onary disease.

We conducted a retrospective analysis of all patients who pre- sented to our ED with chest pain for whom an outpatient stress test- ing protocol was used. This study was approved by the Institutional Review Board at our institution. All patients presenting to our ED with a primary complaint of chest pain during the year 2012 were screened. Patients who were deemed to be low risk, with a non-is- chemic electrocardiogram and two negative troponins, were eligible to be discharged using an outpatient stress testing protocol. A Thrombolysis in Myocardial Infarction score <= 2 is typically considered low risk, but final decisions regarding risk were made by the treating physician.

Out of 5916 ED visits for chest pain, 1260 were selected for the out- patient stress testing protocol (21%). Patient characteristics are present- ed in Table 1. Over 90% had a TIMI score <= 2. Only 6% of patients returned for stress testing with 72 h, 26% within 1 week, and 49% of patients returned for stress testing within 30 days.

Patients who returned for stress testing were older, more likely to have health insurance, and more likely to identify a primary care pro- vider (Table 1). Among those without insurance or a primary care pro- vider, 39% returned for testing, compared to 52% of those with insurance and a primary care provider (p b 0.001). Binary logistic regression showed that only insurance status was independently predictive of returning for stress testing (Odds Ratio 1.31, 95% Confidence Interval 1.03-1.67, p = 0.03).

There were 156 patients with positive or abnormal stress tests

unplanned readmissions, 13 for presumed cardiovascular cause, com- pared to 17 unplanned readmissions, 3 for a presumed cardiovascular cause, in the group that did not undergo stress testing (cardiovascular readmissions 2.4% vs. 0.5%, p = 0.01).

Our study showed that patients rarely adhere to the recommended discharge stress testing protocol, but that there appears to be no impact on subsequent death or myocardial infarction. In a smaller study in a similar population, Milano et al. had similar findings, with 42% of pa- tients returning for testing, but only 6% within 72 h [4]. Studies of pa- tients with insurance, or in other countries, have had more success [5-7]. The yield of stress testing in our low risk population was low, but in line with other studies, which have shown that the incidence of coronary disease in low risk patients presenting to the ED is typically

1.5-2.5% [8,9].

Whether routine outpatient testing in low risk chest pain patients has a significant impact on outcomes is an important question. There were no deaths or myocardial infarctions in those who did or did not undergo testing. In fact, evidence to support such a stress testing strat- egy is limited. Most studies have shown that more testing often leads to more diagnoses of coronary disease and more coronary interventions, but with no impact on death or myocardial infarction [2,10]. In addition, a randomized trial showed that low risk patients can be safely discharged with no further testing [11].

We evaluated the outpatient stress testing protocol for low risk patients presenting to the ED with chest pain at our institution. Less than half of all patients returned for stress testing, and very few within 72 h as recommended. Stress testing had no appreciable impact on death or myocardial infarction, and correlated with a slight increase in readmissions for cardiac causes. We believe that lacking any proven benefit, the recommendation of such a strategy should be reconsidered.

Table 1

Clinical characteristics.

(25%), and 71% were considered normal or likely normal. Of those

with abnormal tests, 31% underwent cardiac catheterization, and 31% of those had significant coronary disease, representing 2% of all patients who underwent stress testing. Of the 15 patients with coronary disease, 13 interventions were performed (3 bypass surgery; 10 coronary stenting). Among patients who did not return for stress testing, there were no cardiac catheterizations or interventions over the 30-day fol- low-up period.

Vital status was available in 99.5% of patients, and there were no deaths during the 30 day follow up period. Clinical follow up was avail- able 87% of patients who did return for stress testing and 88% of those who did not. There were no instances of myocardial infarction during the follow-up period in either group, or any unplanned coronary inter-

Returned for

Did not return

Univariate

Multivariate

ventions. Among the patients who did return for testing, there were 26

^a Not included due to correlation with Health Insurance variable.

0735-6757/(C) 2017

Conflict of interest

None.

Jessica R. Balderston, MD Taruna Aurora, MD Richard Zhang, DO

esmolol for Atrial fibrillation or atrial flutter (AFL) in post-open heart patients [4-5]. Other studies have compared calcium channel blockers and Beta blockers for Afib/AFL in the ED with mixed results [6-8]. The purpose of this study was to compare the efficacy and safety of diltiazem and esmolol when used for acute Rate control for tachyarrythmias in the ED. The primary outcome was the proportion of patients achieving acute rate control within 30 min, defined as a

Department of Emergency Medicine, Virginia Commonwealth University

Richmond, VA, United States

Michael C. Kontos, MD Zachary M. Gertz, MD*

Division of Cardiology, Virginia Commonwealth University. Richmond, VA,

United States

*Corresponding author at: West Hospital, 1200 E Broad St., PO Box

980036, Richmond, VA 23298, United States.

E-mail address: [email protected] (Z. Gertz).

17 January 2017

http://dx.doi.org/10.1016/j.ajem.2017.04.004

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   agement of patients with non-ST-elevation acute coronary syndromes: a report of the American College of Cardiology/American Heart Association Task Force on Prac- tice Guidelines. J Am Coll Cardiol 2014;64:e139-228.

   Milano P, Carden DL, Jackman KM, et al. Compliance with outpatient stress testing in low-risk patients presenting to the emergency department with chest pain. Crit Pathw Cardiol 2011;10:35-40.

4. Meyer MC, Mooney RP, Sekera AK. A critical pathway for patients with acute chest pain and low risk for short-term adverse cardiac events: role of outpatient stress testing. Ann Emerg Med 2006;47:427-35.
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   agnostic algorithm with selective outpatient stress testing for emergency depart- ment patients with potential ischemic chest pain. Ann Emerg Med 2012;59:256-64.

   Paoloni R, Ibuowo R. A cohort study of chest pain patients discharged from the emergency department for early outpatient treadmill exercise stress testing. Emerg Med Australas 2013;25:416-21.

6. Hermann LK, Newman DH, Pleasant WA, et al. Yield of routine provocative cardiac testing among patients in an emergency department-based chest pain unit. JAMA Intern Med 2013;173:1128-33.
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   Diltiazem versus esmolol for acute rate control in the emergency department

   

   Management of tachyarrythmias in the emergency department (ED) often includes prompt treatment with medications such as diltiazem or esmolol [1-3]. Few studies have evaluated the use of diltiazem and

   heart rate b 100 bpm. Secondary outcomes included the proportion of patients with rate control within 60 and 120 min; the mean percent and absolute decrease in heart rate within 30, 60, and 120 min; and composite adverse events, defined as systolic blood pressure b 90 mm Hg or heart rate b 60 bpm.

   This was an IRB-approved retrospective cohort study. Patients who presented to the ED from January 1, 2010 to September 30, 2015 and treated with Intravenous diltiazem or esmolol were eligible for inclu- sion. Patients were excluded if the baseline heart rate was b 100 beats per minute (bpm) or if other rate control agents were administered prior to the study medications. Screening was conducted to include an equal number of patients in each arm. Heart rates were evaluated retro- spectively by study investigators using the electronic medical record (EMR).

   At this institution, the protocol for diltiazem is weight-based, and is administered as a bolus every 15 min for two doses of 0.25 mg/kg and

   0.35 mg/kg (max 25 and 35 mg, respectively). After an additional 15 min, a continuous, titratable infusion of 5 mg/h may be initiated, to a max of 15 mg/h. The dosing strategy for esmolol includes an optional bolus (500 mcg/kg) and a 50-300 mcg/kg/min continuous infusion. Bolus doses may be reduced or omitted at the physician’s discretion based on clinical judgment.

   A total of 115 patients were screened in the esmolol group and 22 patients met inclusion criteria (Fig. 1). Study investigators were unable to include more patients prior to the start of the study period. In the dil- tiazem group, 49 patients were screened in reverse chronological order and 22 patients met inclusion criteria to match the sample size of the esmolol group.

   initial cardiac rhythms (Fig. 1), age, and baseline systolic blood pres- sure were similar between the two groups (Table 1). The baseline heart rate was higher in the esmolol group than in the diltiazem group.

   Acute rate control within 30 min was achieved in 58% of patients in the diltiazem group and 43% in the esmolol group (p = 0.53). There were no significant differences between the proportions of patients achieving rate control within any timeframe (Fig. 2). When comparing groups after 60 min, the proportion of patients achieving rate control remained 50% in the esmolol group, but increased to 76% in the diltia- zem group (Fig. 3).

   In this study, baseline characteristics between the two groups were similar, except for the higher baseline heart rate in the esmolol group (Table 1). Although baseline heart rates were dissimilar, mean percent and absolute decrease in heart rate were found to be similar at all time points (Table 2). The proportion of patients in the diltiazem group achieving rate control increased by 29% in the second hour of treatment, however no increase was observed in the esmolol group dur- ing this hour. The number of boluses administered were similar be- tween the two groups (p = 0.91). The incidence of adverse events was also similar between groups.

   Some limitations have been identified. This was a retrospective study, and therefore recall bias could be introduced as investigators are required to rely on accuracy of documentation in the EMR. The re- quired number of patients to assess the primary outcome was not met, likely due to the esmolol being used for indications other than rate control, such as aortic dissection. Furthermore, the study was not able to detect any differences in adverse events due to a smaller sample size. The primary outcome of rate control within 30 min may have been influenced by a higher baseline heart rate in the esmolol group, poten- tially making rate control more difficult in comparison to the diltiazem group.