David Hamilton

Prospective evaluation of the use of the thrombolysis in myocardial infarction score as a risk stratification tool for chest pain patients admitted to an ED observation unit.

BACKGROUND The Thrombolysis in Myocardial Infarction (TIMI) score has shown use in predicting 30-day and 1-year outcomes in emergency department (ED) patients with potential acute coronary syndrome. Few studies have evaluated the TIMI score in risk stratifying patients selected for the ED observation Unit (EDOU). Risk stratification of patients in this group could identify those at risk for significant cardiac events. Our goal was to evaluate TIMI use for risk stratification in this population and compare outcomes among differing scores. METHODS A prospective observational study with 30-day telephone follow-up for a 12 month period. Baseline data, outcomes related to EDOU stay, admission, and 30-day outcomes were recorded. TIMI scores were calculated for each patient placed in EDOU. TIMI score was not utilized in the decision to place patients in observation. RESULTS N = 552. Composite outcomes recorded were myocardial infarction, revascularization, or death either during the EDOU stay, inpatient admission, or the 30-day follow-up. Eighteen composite outcomes were recorded: stent (12 patients), coronary artery bypass graft (3 patients), myocardial infarction and stent (2 patients), and myocardial infarction, and coronary artery bypass graft (1 patient). Distribution by TIMI score was: 0 (102 patients), 1 (196), 2 (142), 3 (72), 4 (27), and 5 (5). Risk of composite outcome increased by score: 0 (1%), 1 (2.6%), 2 (2.1%), 3 (6.9%), 4 (11.1%), and 5 (20%). Those with an intermediate risk score (3-5) were also more likely to require admission (15.4% vs 9.8%, P = .048). CONCLUSION The TIMI risk score may serve as an effective risk stratification tool among chest pain patients selected for EDOU placement. Patients with intermediate-risk by TIMI may be considered for inpatient admission and/or more aggressive evaluation and therapy.

Treatment of Low-risk Pulmonary Embolism Patients in a Chest Pain Unit

BACKGROUND Several studies have proposed the Pulmonary Embolism Severity Index (PESI) as a risk stratification tool for discharge of low-risk pulmonary embolism (PE) patients from the emergency department (ED) and treatment as outpatients, but this has not become accepted standard of care in the United States. Chest pain units (CPUs) may serve as ideal locations for the treatment and risk-stratification of low-risk PE patients, thus avoiding lengthy inpatient stays while assuring patients are appropriate for outpatient therapy for PE. We sought to characterize the number of patients at our institution who may be eligible for a short stay in our CPU and then established a protocol for the treatment of low-risk patients in the CPU. METHODS We identified all patients admitted to the University of Utah Medical Center from the ED with a diagnosis of PE over the 6-year period between 2002 and 2007. We retrospectively reviewed the electronic medical records to identify clinical variables to calculate a PESI score for each patient. Patients who were considered to be low-risk, on the basis of PESI score (class I and II), were considered eligible for treatment in the CPU, and, on the basis of this, we estimated numbers of patients to be treated in the CPU and patient demographics. We determined results of transthoracic echocardiography (TTE) and bilateral lower extremity (BLE) venous duplex ultrasound for PE patients to estimate potential inpatient admission rates from the CPU. We reviewed the electronic medical records during the 30-day period after hospital admission for patient mortality. We then created a protocol for the treatment of these low-risk patients in the CPU. RESULTS A total of 545 patients were admitted with PE during the 6-year period. Of these patients, 282 were considered low risk and potentially appropriate for treatment of PE in the CPU. Of those, 43.3% were male, and the average age was 43.9 years (range: 14-92 years). Mortality was 0% for the low-risk group over the 30 days after hospital admission. A total of 108 patients had TTE performed and, of these, 30 had evidence of right heart strain. Ninety patients had BLE venous duplex and, of these, 15 had a deep venous thrombosis proximal to the popliteal veins. On the basis of our findings, we created a protocol for treatment of low-risk PE patients in the CPU. Patients who are low risk according to PESI score are admitted to the CPU with administration of low-molecular-weight heparin in the ED and initiation of oral anticoagulation therapy. Patients are monitored on telemetry for at least 12 hours, with performance of BLE duplex and TTE while in the CPU. Patients are admitted to an inpatient unit from the CPU if during their stay they exhibit unstable vital signs, a new arrhythmia, deep venous thrombosis proximal to the popliteal veins on BLE duplex, or signs of right heart strain on TTE. Patients who do not meet these criteria are considered appropriate for outpatient treatment and discharged with low-molecular-weight heparin and oral anticoagulation with thrombosis clinic follow-up. Given our findings from the retrospective chart review, we estimated that, at our institution, 4 patients per month would be eligible for treatment of PE in the CPU. With the findings on TTE and BLE duplex, we estimated that 25.3% of eligible patients would eventually require inpatient admission from the CPU. CONCLUSIONS We identified a number of low-risk patients who may be eligible for treatment of PE in our CPU. Given the resources of the CPU, this may serve as an ideal location for the treatment of low-risk PE patients and allow further risk stratification and consultation beyond that typically readily available in the ED. We described the creation of a protocol for the treatment of low-risk patients with PE in a CPU.

Prospective evaluation of the treatment of intermediate-risk chest pain patients in an emergency department observation unit.

BACKGROUND Emergency department observation units (EDOUs) serve an important role in the evaluation and risk stratification of low-risk chest pain patients. OBJECTIVES Our goal was to evaluate our EDOU protocol for intermediate-risk chest pain patients and compare outcomes and inpatient admission rates for low-risk and intermediate-risk patients. METHODS Prospective observational study with 30-day telephone follow-up for all chest pain patients admitted to our EDOU from June 1, 2009 to May 31, 2010. Our protocol for intermediate-risk chest pain patients includes patients with a self-reported history of coronary artery disease and negative initial cardiac testing in the emergency department. The EDOU protocol involves telemetry, serial cardiac biomarker testing, and mandatory cardiology consultation. RESULTS A total of 552 chest pain patients were evaluated, including 100 (18.1%) intermediate-risk and 452 (81.9%) low-risk patients. Intermediate-risk chest pain patients were significantly more likely to have a myocardial infarction or undergo revascularization (stent or coronary artery bypass graft) (8.0% vs. 2.2%, P = 0.008). Intermediate-risk patients had a higher inpatient admission rate (16.0% vs. 8.8%, P = 0.032). There were no significant unanticipated adverse events at 30-day follow-up in either group. CONCLUSIONS In conclusion, intermediate-risk chest pain patients in an EDOU had higher rates of significant cardiac events and inpatient admission. Intermediate-risk patients may be appropriate for EDOU placement, given the acceptable inpatient admission rate and the lack of significant adverse events in the 30-day follow-up period. However, given the higher rate of significant cardiac events, the results of our study emphasize the need for increased vigilance and close cardiology consultation in the intermediate-risk group.

Prospective evaluation of a simplified risk stratification tool for patients with chest pain in an emergency department observation unit.

BACKGROUND The Thrombolysis in Myocardial Infarction score has been validated as a risk stratification tool in the emergency department (ED) setting, but certain aspects of the scoring system may not be applicable when applied to patients with chest pain selected for ED observation unit (EDOU) stay. We evaluated a simplified, 3-point risk stratification tool for patients in EDOU, which we termed the CARdiac score: Coronary disease [previous myocardial infarction (MI), stent, or coronary artery bypass graft (CABG)], Age (65 years or older), and Risk factors (at least 3 of 5 cardiac risk factors). METHODS We performed a prospective, observational study with 30-day phone follow-up for all patients with chest pain admitted to our EDOU over a 36-month period. Baseline data, outcomes related to EDOU stay, inpatient admission, and 30-day outcomes were recorded. CARdiac scores were calculated based on patient history and were used to evaluate the risk of the composite outcome of MI, stent/CABG, or death during the EDOU stay. CARdiac scores were also used to evaluate the risk of inpatient admission. The CARdiac score was not used during the EDOU stay and was calculated blinding to patient outcomes. RESULTS One thousand two hundred seventy-six patients were evaluated. Average age was 54.1 years (18-92 years) and 46% were male. Forty patients experienced composite outcomes: stent (32), CABG (4), MI and stent (2), MI and CABG (1), and MI (1). Risk of the composite outcome generally increased by CARdiac score: 0 (1.5%), 1 (3.6%), 2 (9%), and 3 (5.4%). Patients with a CARdiac score of 2 or 3 (moderate risk) were significantly more likely to experience MI, stent, or CABG than those with a score of 0 or 1 (low risk): 16/193 moderate-risk patients (8.3%) had the composite outcome versus 24/1083 low-risk patients (2.2%, P < 0.001, relative risk = 3.8). Those at moderate risk by the CARdiac score were also more likely to require inpatient admission from the EDOU (17.6% vs. 9.8%, P < 0.001). CONCLUSION The CARdiac score may prove to be a simple tool for risk stratification of patients with chest pain in an EDOU. Patients at moderate risk by CARdiac score may be appropriate for more intensive evaluation in the EDOU or consideration for inpatient admission rather than EDOU placement.

Prospective evaluation of outcomes among geriatric chest pain patients in an ED observation unit

OBJECTIVE Because of concerns of high admission rates and adverse events in geriatric patients, hospitals may exclude this group from emergency department observation unit (EDOU) chest pain protocols. We sought to evaluate characteristics and outcomes of geriatric chest pain patients treated in an EDOU. METHODS We performed a prospective, observational study of chest pain patients admitted to our EDOU over a 36-month period. We recorded baseline demographics and risk factors as well as outcomes related to the EDOU stay. We performed 30-day follow-up using telephone contact and review of the electronic medical record. RESULTS Over the 36-month study period, 1276 chest pain patients agreed to participate in the study. Two hundred seventy-six patients (21.6%) were 65 years and older. Geriatric patients in the EDOU were more likely to report a history of coronary artery disease than nongeriatric patients (27.1% vs 11.6%, P<.001). There were no clinically significant adverse events nor deaths among geriatric patients. The proportion of geriatric patients who experienced myocardial infarction, stent, or coronary artery bypass graft during the EDOU stay or follow-up period was 4.7% vs 2.7% for nongeriatric patients (P=.09). Inpatient admission rates were significantly higher for geriatric patients (15.6% vs 9.7%, P=.006). Similarly, geriatric patients had higher rates of cardiac catheterization than did nongeriatric patients (13.4% vs 7.9%, P=.005). CONCLUSION Geriatric patients with chest pain may represent a higher-risk group for evaluation in the EDOU. In our experience, however, these patients were safely evaluated in the EDOU setting and their inpatient admission rate fell within generally accepted guidelines.

Utilization and Safety of a Pulmonary Embolism Treatment Protocol in an Emergency Department Observation Unit.

UNLABELLED Pulmonary embolism (PE) is a common disease in emergency medicine and treatment approaches vary greatly. Emergency department observation units (EDOUs) have provided the opportunity to complete a PE workup, initiate treatment, and arrange appropriate follow-up for low-risk patients. OBJECTIVE We sought to evaluate the utilization and safety of a treatment protocol for low-risk PE in an EDOU. METHODS A prospective evaluation was performed in our EDOU for the treatment of low-risk PE between December 1, 2010 and May 31, 2012. The PE treatment protocol included telemetry monitoring, initiation of anticoagulation, performance of an echocardiogram, bilateral lower extremity duplex ultrasound, and consultation by the hospitals thrombosis service to arrange outpatient follow-up. The primary outcome measure was inpatient admission and any complications during the EDOU stay or during a 30-day follow-up period. RESULTS Twelve patients were assigned to the EDOU for the PE treatment protocol during the 18-month study period. Six patients (50%) were admitted to an inpatient unit following the EDOU stay. Reasons for inpatient admission included hypoxia/worsening dyspnea (2), right ventricular strain on echocardiogram (1), large clot burden on duplex ultrasound (1), and lack of availability of testing/thrombosis service consultation during the EDOU stay (2). There were no adverse events in the EDOU. All patients reported compliance with outpatient follow-up, and none of the patients reported hospitalization or adverse events during the 30-day follow-up period. Utilization of the PE treatment protocol in our EDOU was surprisingly low (<1 patient/month), possibly because of provider awareness of the protocol. CONCLUSIONS Although the overall inpatient admission rate from the EDOU was high, some of these cases related to logistical issues rather than medical concerns or complications. Further evaluation of an EDOU PE protocol may continue to demonstrate the safety and efficiency of this approach when compared with inpatient admission.

Significance of an Indeterminate Troponin I in Patients Evaluated for Chest Pain in an Emergency Department Observation Unit.

BACKGROUND Previous studies have suggested that patients with an indeterminate troponin I (TnI) in the emergency department (ED) are significantly more likely to be diagnosed with acute myocardial infarction (MI). The role of the ED observation unit (EDOU) in the evaluation of these patients is unclear. OBJECTIVE We sought to determine the risk of MI and revascularization in chest pain patients with an indeterminate TnI in the ED, who were placed in an EDOU. METHODS We performed a prospective evaluation with 30-day follow-up for all chest pain patients placed in the University of Utah EDOU between June 1, 2009 and May 31, 2012. The EDOU excludes patients with a positive TnI, significant electrocardiogram changes, or active chest pain; however, the EDOU is utilized for further evaluation of patients who have an initial indeterminate TnI (0.06 ng/mL-0.49 ng/mL) with serial TnI measurements, cardiology consult, and potential provocative testing. We identified all patients who had an indeterminate TnI on initial testing in the ED. Primary outcomes were MI, revascularization with cardiac stent or coronary artery bypass graft, and death. RESULTS We evaluated 1276 chest pain patients in the EDOU over the 3-year study period (average age: 54.1 years, 54% female). Fifty-eight patients (4.5%) had an initial indeterminate TnI. There were no deaths or adverse outcomes in the EDOU among those with an indeterminate TnI, and none of these patients developed a positive TnI during their hospital stay or 30-day follow-up. Patients with an indeterminate TnI had a higher rate of inpatient admission from the EDOU (24.1% vs. 10.3%; P=0.001). Among those with an indeterminate TnI, 8.6% underwent revascularization, while the rate of revascularization or MI was 2.9% among those who did not have an initial indeterminate TnI (P=0.032). CONCLUSION Patients evaluated in our EDOU for chest pain with an initial indeterminate TnI did not develop subsequent MI. However, these patients had an increased rate of revascularization and inpatient admission compared with controls. While our experience suggests that patients with an indeterminate TnI may be safely evaluated in an observation setting, EDOUs which treat only low-risk chest pain patients may wish to recommend inpatient admission for this patient group.