Abstract
Objective:
The objective was to determine the impact of the HEART Pathway on health care utilization and safety outcomes at 1 year in patients with acute chest pain.
Methods:
Adult emergency department (ED) patients with chest pain (N= 282) were randomized to the HEART Pathway or usual care. In the HEART Pathway arm, ED providers used the HEART score and troponin measures (0 and 3 hours) to risk stratify patients. Usual care was based on American College of Cardiology/American Heart Association guidelines. Major adverse cardiac events (MACE—cardiac death, myocardial infarction [MI], or coronary revascularization), objective testing (stress testing or coronary angiography), and cardiac hospitalizations and ED visits were assessed at 1 year. Randomization arm outcomes were compared using Fisher’s exact tests.
Results:
A total of 282 patients were enrolled, with 141 randomized to each arm. MACE at 1 year occurred in 10.6% (30/282): 9.9% in the HEART Pathway arm (14/141; 10 MIs, four revascularizations without MI) versus 11.3% in usual care (16/141; one cardiac death, 13 MIs, two revascularizations without MI; p = 0.85). Among low-risk HEART Pathway patients, 0% (0/66) had MACE, with a negative predictive value (NPV) of 100% (95% confidence interval = 93%–100%). Objective testing through 1 year occurred in 63.1% (89/141) of HEART Pathway patients compared to 71.6% (101/141) in usual care (p = 0.16). Nonindex cardiac-related hospitalizations and ED visits occurred in 14.9% (21/141) and 21.3% (30/141) of patients in the HEART Pathway versus 10.6% (15/141) and 16.3% (23/141) in usual care (p = 0.37, p = 0.36).
Conclusions:
The HEART Pathway had a 100% NPV for 1-year safety outcomes (MACE) without increasing downstream hospitalizations or ED visits. Reduction in 1-year objective testing was not significant.
Care patterns for the evaluation of emergency department (ED) patients with possible acute coronary syndrome (ACS) in the United States are heterogeneous, inefficient, and costly.1–3 Of 8 to 10 million annual ED presentations for chest pain, over 50% are hospitalized or observed for lengthy evaluations with serial cardiac biomarkers and stress testing or coronary angiography.4 However, less than 10% of these patients are ultimately diagnosed with ACS, and this inefficient care costs an estimated $10 to $13 billion annually.5–8
It is the American College of Cardiology/American Heart Association (ACC/AHA) recommendation that low-risk patients with acute chest pain should receive serial cardiac markers followed by objective cardiac testing (stress testing or cardiac imaging).9 However, among low-risk patients, this care fails to accurately focus health system resources on those likely to benefit.10 In addition, objective cardiac testing is associated with a substantial number of false-positive and nondiagnostic tests, which often lead to invasive testing among the low-risk patient group, who have ACS rates less than 2%.11 There is a building consensus within the U.S. health care system regarding the need to more efficiently evaluate patients with acute chest pain.12
The HEART Pathway,13,14 which combines the HEART score15–18 with 0- and 3-hour cardiac troponin tests, is a decision aid designed to identify ED patients who are safe for early discharge. The HEART Pathway randomized controlled trial (RCT) demonstrated significant reductions in objective cardiac testing, hospitalizations, length of stay, and cost, without missing adverse events or increasing cardiac-related return care at 30 days.19,20 However, the ability of the HEART Pathway to predict adverse events and its impact on downstream health care utilization (recurrent cardiac-related ED visits or hospitalizations and objective cardiac testing) has not been studied beyond 30 days. To address this evidence gap, we evaluated 1-year major adverse cardiac event (MACE) rates and cardiovascular health care utilization rates among patients randomized to the HEART Pathway versus usual care. We hypothesized that patients identified as low-risk by the HEART Pathway would have a 1-year MACE rate of <1% and that downstream health care utilization would not be increased in the HEART Pathway arm.
METHODS
Study Design
We conducted a preplanned, secondary analysis of a randomized, controlled, single-center clinical trial funded by the AHA from September 2012 to February 2014. All participants provided witnessed written informed consent and were randomized to the HEART Pathway or usual care strategies. In the HEART Pathway Arm, ED attending physicians used the HEART Pathway to guide testing and disposition decisions.20 In the usual care arm, providers were encouraged to follow ACC/AHA guidelines.9,21,22 This trial was approved by the institutional review board of the sponsoring organization and was registered with clinicaltrials.gov (clinical trial number NCT01665521) prior to enrollment. Methods of the HEART Pathway trial have been previously described.20
Study Setting
The ED of a tertiary care academic medical center (institution name withheld for review) located in the Piedmont Triad area of North Carolina, serving urban, suburban, and rural populations served as the location for participant recruitment. Board-certified or board-eligible emergency physicians staff the ED 24 hours per day, 7 days a week. They directly provide care and oversee care provided by residents, physician assistants, and nurse practitioners. Annual ED patient volume at the time of enrollment consisted of approximately 104,000 patient encounters. Exercise stress echocardiogram, dobutamine stress echocardiogram, coronary computed tomography angiography, stress nuclear imaging, stress cardiac magnetic resonance imaging, or invasive coronary angiography were routinely available to study participants. Serum troponin measurements were performed using the ADVIA Centaur platform TnI-Ultra assay (Siemens), which has a 99th percentile of the upper reference limit and 10% CV at 0.04 μg/L.
Study Population
Patients were screened by research staff (6 days excluding Saturday, 80 hours/week) if they were at least 21 years old and had any symptoms that could suggest possible ACS. Inclusion criteria were satisfied if the provider ordered an electrocardiogram (ECG) and troponin for the evaluation of ACS. Consistent with prior studies, patients were excluded for the following reasons: new ST-segment elevation > 1 mm; hypotension; life expectancy < 1 year; a noncardiac medical, surgical, or psychiatric illness determined by the provider to require admission; prior enrollment; non–English speaking; and incapacity or unwillingness to consent.23–25 This carefully selected group of patients was the population of patients in which chest pain risk stratification would be applied.
Study Protocol
Trial participants were stratified by presence of known coronary disease (including prior revascularization) and randomized within strata to one of the two treatment arms (HEART Pathway or usual care arms) with equal probability using random permuted block randomization. The randomization sequence was generated using nQuery Advisor 6.0 (Statistical Solutions) and integrated into a secure electronic database, REDCap,26 which was used by the study coordinators to register participants and obtain study group assignments. Study investigators and staff were blinded to the randomization sequence.
HEART Pathway.
Attending ED providers used a validated clinical decision aid, the HEART score,15–18 and serial troponin measures at 0 and 3 hours after ED presentation to risk stratify participants randomized to the HEART Pathway arm. The HEART score consists of five components; History, Electrocardiogram (ECG), Age, Risk factors, and Troponin (Data Supplement S1, available as supporting information in the online version of this paper, which is available at http://onlinelibrary.wiley.com/doi/10.1111/acem.13504/full ). To calculate a HEART score, first each component is assessed (on a scale of 0 to 2) and then component scores are summed to produce the final score. A HEART score of 0 to 3 confers a low-risk assessment, while a score of 4 or greater confers a high-risk assessment. Based on the HEART score and serial troponin results the attending ED provider received care recommendations according to the HEART pathway (Figure 1). For patients with low-risk HEART scores (HEART score of 0–3) and negative troponin results, the HEART pathway recommends discharge from the ED without further testing. These patients were encouraged to follow up with their primary care provider. In patients with a high-risk HEART score (HEART score of >4) or a troponin above the 99th percentile threshold, the HEART Pathway recommends further evaluation in the hospital or observation unit (OU).
Figure 1.
HEART Pathway algorithm. This figure was corrected on 2018–09-17 after initial online publication to correct the spelling of the label “HEART Score.”
Usual Care.
The care conveyed in the usual care arm was at the discretion of the care providers and not determined by trial protocol. Nevertheless, providers were encouraged to follow ACC/AHA guidelines,9,21,22 which endorse serial cardiac biomarkers and objective cardiac testing prior to discharge from the OU or inpatient ward for patients with symptoms suggestive of ACS.13,27
HEART Pathway Adherence.
The care provided in both randomization arms was ultimately determined by provider discretion and not mandated by trial protocol. The HEART Pathway was used by providers as a decision aid rather than a alternative for clinical judgment. For that reason, a level of nonadherence to the care delivery described in Figure 1 was anticipated.
HEART Score Agreement.
A physician study investigator blinded to the initial assessment by the patient’s attending physician calculated a second HEART score assessment for patients randomized to the HEART Pathway. Our institutional IRB required that if the attending provider determined the patient to be low risk, but the study investigator found the patient to be high risk, the attending ED provider was made aware of this discrepancy.
Measurements
This trial was conducted in accordance with standards of Good Clinical Practice, Standardized Reporting Guidelines,28 and Key Data Elements and Definitions.29 A detailed sources of data map was created prior to study commencement. Electronic medical records (EMRs) were used as the source for data elements consistently contained in the medical record. REDCap data collection templates were utilized to prospectively collect and store data from patients and care providers for data elements not reliably present in the EMR.
Structured record review follow-up was conducted during the index visit. At 1 year, a second structured record review was followed by a telephone interview using a validated scripted follow-up dialogue30 to further clarify events since discharge, to identify events occurring at other care facilities, and to determine health care utilization since discharge. Outcome events reported at other health care facilities were established using a structured review of those medical records. Incomplete follow-up at 1 year was conducted using the following algorithm: participants with ongoing visits in the EMR were considered to have complete information and were classified based on the data available in the medical record; participants with no ongoing visits were considered lost to follow-up at the point of last contact. The Social Security Death Master File was used to systematically search for participants unable to be contacted. In the event of incongruity between a participant’s self-reported event and the medical record, the medical record was considered accurate.
Outcomes
The primary outcome was major adverse cardiac events (MACEs), defined by a composite endpoint of cardiovascular mortality, myocardial infarction (MI), or coronary revascularization, from enrollment through 1 year of follow-up.31 Cardiovascular death was based on the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial definition (available at accordtrial.org).32 MI was defined based on the universal definition of MI.33 Coronary revascularization was defined as angioplasty with or without stent placement, or coronary artery bypass surgery. Secondary outcomes included objective cardiac testing, cardiac-related recurrent ED visits, and nonindex hospitalizations at 1 year. Cardiac-related recurrent ED visits were defined as any return visit to the ED with symptoms suggestive of ACS within the 1 year follow-up period. Cardiac related non-index hospitalization was defined as an inpatient or OU evaluation for symptoms suggestive of ACS within 1 year. Objective cardiac testing was defined as any stress test or coronary angiography procedure within 1 year of enrollment.
Endpoint Adjudication.
A consensus of three emergency physician reviewers (CDM, CWL, BCH), blinded to treatment arm assignment, adjudicated elements required to measure the occurrence of MACE and to determine cardiac-relatedness of deaths, recurrent ED visits, and nonindex hospitalizations. Reviewers were provided participant’s index and discharge records, follow-up call information, records obtained from follow-up, and study definitions to make these assessments. Any dissimilarities were settled by reviewer consensus.
Data Analysis
The proportion of patients with 1-year MACE were estimated for the HEART Pathway and usual care groups and a 95% confidence interval (CI) for the differences between the two groups was calculated using exact calculations. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) and their exact 95% CIs for MACE over the 365 day follow-up period were calculated for each treatment arm. Missed MACE rates were estimated for the HEART Pathway and usual care groups and an exact 95% CI for the differences between the two groups were calculated. This study was powered (N= 282) for the primary analysis;20 to detect a 15% reduction in 30-day objective testing at 80% with 5% two-sided level of significance and 10% loss to follow-up.
Proportions of patients receiving objective cardiac testing, cardiac-related ED visits, and hospitalizations through 1 year were estimated for the HEART Pathway and usual care groups and a 95% CI for the differences between the two groups was calculated using exact calculations. Unadjusted differences between groups in these outcomes at index and 30 days were assessed using the Fisher’s exact test. As is consistent with prior trials, patients with incomplete follow-up were considered to be free of MACE events.13, 14,20,34 All outcomes were analyzed using intention to treat. Statistical analysis was performed using SAS 9.4.
RESULTS
From September 2012 to February 2014, a total of 282 patients with symptoms suggestive of ACS were enrolled, with 141 randomized to each arm (Figure 2). Patient characteristics are summarized in Table 1. No participants were removed from the study after randomization. Assessment for 1-year events was complete on 90.43% (255/282) of participants, with an additional three patients having vital status data, leaving 8.5% (24/282) lost to follow-up. There was no statistically significant difference in loss-to-follow-up rates between randomization arms (p = 0.13). Among the 141 patients randomized to the HEART Pathway, 46.8% (66/141) were classified as low risk and 53.2% (75/141) as high risk.
Figure 2.
HEART pathway RCT flow diagram. RCT = randomized controlled trial.
Table 1.
HEART Pathway RCT Patient Characteristics
| Patient Characteristics | HEART Pathway | Usual Care | ||
|---|---|---|---|---|
| Number (n= 141) | Percent | Number (n= 141) | Percent | |
| Age (years), mean ± SD | 53.4 ± 12.0 | 53.1 ± 12.2 | ||
| Sex | ||||
| Female | 81 | 57.4 | 81 | 57.4 |
| Race | ||||
| Caucasian | 90 | 63.8 | 93 | 66.0 |
| African American | 48 | 34.0 | 46 | 32.6 |
| Asian | 1 | 0.7 | 0 | 0 |
| Native American | 1 | 0.7 | 1 | 0.7 |
| Other | 1 | 0.7 | 1 | 0.7 |
| Ethnicity | ||||
| Hispanic | 1 | 0.7 | 4 | 2.8 |
| Not Hispanic | 140 | 99.3 | 137 | 97.2 |
| Risk factors | ||||
| Current smoking | 42 | 29.8 | 34 | 24.1 |
| Recent cocaine (past 90 days) | 3 | 2.1 | 3 | 2.1 |
| Hypertension | 75 | 53.2 | 82 | 58.2 |
| Hyperlipidemia | 61 | 43.3 | 60 | 42.6 |
| Diabetes | 31 | 22.0 | 27 | 19.2 |
| Family history of coronary disease | 44 | 31.4 | 58 | 41.4 |
| BMI > 30 (kg/m2) | 71 | 50.4 | 81 | 57.5 |
| TIMI risk score > 1 | 60 | 42.6 | 63 | 44.7 |
| Prior coronary disease | 28 | 19.9 | 29 | 20.6 |
| Prior MI | 21 | 14.9 | 24 | 17.0 |
| Prior PCI | 14 | 9.9 | 19 | 13.5 |
| Prior CABG | 7 | 5.0 | 3 | 2.1 |
| Prior cerebral vascular disease | 3 | 2.1 | 9 | 6.4 |
| Prior peripheral vascular disease | 4 | 2.8 | 4 | 2.8 |
| Insurance status | ||||
| Insured | 105 | 74.5 | 106 | 76.3 |
| Private | 71 | 50.4 | 68 | 48.9 |
| Medicare | 21 | 14.9 | 21 | 15.1 |
| Medicaid | 13 | 9.2 | 17 | 12.2 |
| Uninsured | 36 | 25.5 | 33 | 23.7 |
BMI = body mass index; CABG = coronary artery bypass graft; MI = myocardial infarction; PCI = percutaneous coronary intervention.
Major adverse cardiac events at 1 year of randomization occurred in 10.6% (30/282) with one cardiac death, 23 MIs, and six revascularizations without MI. In addition to the single cardiac death, there were two noncardiac deaths (both in the usual care arm) and three deaths with an unknown cause (one in the usual care arm and two in the HEART Pathway arm, both of whom were classified as high risk by the HEART Pathway). Among patients randomized to the HEART Pathway 9.9% (14/141) had MACE at 1 year (10 MIs, four revascularizations without MI) compared to 11.3% (16/141) in the usual care arm (one cardiac death, 13 MIs, two revascularizations without MI; p = 0.85). No patients identified as low risk by the HEART Pathway (0/66) suffered 1 year MACE. Test characteristics of the HEART Pathway are presented in Table 2.
Table 2.
Test Characteristics of HEART Pathway Detection of MACE at 365 Days
| HEART Pathway Assessment | 365-Day MACE | Total (n) | ||
|---|---|---|---|---|
| yes (n) | no (n) | |||
| High risk | 14 | 61 | 75 | |
| Low risk | 0 | 66 | 66 | |
| Total (n) | 14 | 127 | 141 | |
| Sensitivity (95% CI) |
Specificity (95% CI) |
PPV (95% CI) |
NPV (95% CI) |
|
| HEART Pathway | 100% (76.8%–100%) |
52.0% (42.93%–60.9%) |
18.7% (5.5%–16.1%) |
100% (94.6%–100%) |
MACE = major adverse cardiac event; NPV = negative predictive value; PPV = positive predictive value.
Cardiac-related repeat ED visits occurred in 21.3% (30/141) of patients in the HEART Pathway arm compared to 16.3% (23/141) in the usual care arm (p = 0.36). Among low-risk patients in the HEART Pathway arm 13.6% (9/66) had 1-year cardiac-related repeat ED visits. Cardiac-related nonindex hospitalizations occurred in 14.9% (21/141) of patients in the HEART Pathway arm compared to 10.6% (15/141) in the usual care arm (p = 0.37). Cardiac related non-index hospitalization occurred in 8% (5/66) of patients classified as low risk by the HEART Pathway.
Objective cardiac testing at 1 year (including index visit testing) occurred in 63.1% (89/141) of patients in the HEART Pathway compared to 71.6% (101/141) in usual care (p = 0.16). Nonindex objective testing (occurring between index visit and 1 year) occurred in 12.8% (36/282) patients; 30.6% (11/36) of these occurred in patients who had already had index objective cardiac testing. Nonindex objective testing occurred in 17.0% (24/141) of patients in the HEART Pathway arm compared to 8.5% (12/141) in usual care (p = 0.049). Among patients classified as low risk by the HEART Pathway, 21% (14/66) received stress testing after their index visit with 93% (13/14) negative for inducible ischemia. The one low-risk patient with a positive stress test was further evaluated with invasive coronary angiography, which was negative for obstructive coronary artery disease.
DISCUSSION
Prior work has demonstrated that the HEART Pathway reduces objective testing through 30 days, shortens length of stay, and increases early discharges while maintaining a >99% NPV for MACE at 30 days.20 However, prior to this study, the ability of the HEART Pathway to predict MACE out to 1 year and its impact on long-term health care utilization were unknown. Results of this trial suggests that the HEART Pathway may accurately risk stratify patients for 1 year after their index visit. Furthermore, it suggests that the up-front increase in early discharges produced by the HEART Pathway does not lead to a significant increase objective cardiac testing or downstream cardiovascular related ED visits and hospitalizations. However, the HEART Pathway’s up-front reduction in objective cardiac testing was attenuated over time with more patients in the HEART Pathway arm receiving this testing after their index visit.
We previously demonstrated that objective cardiac testing at index and 30 days was significantly reduced by the HEART Pathway compared to usual care. The HEART Pathway reduced objective cardiac testing by 15% during the index visit and 12% from index through 30 days (both statistically significant).20 However, at 1 year, while the HEART Pathway reduced objective cardiac testing by 8.5%, this difference was no longer statistically significant. In fact, downstream testing increased among HEART Pathway patients, with 14 low-risk patients receiving nonindex stress tests. Stress tests in these low-risk patients were of questionable benefit, resulting in one false-positive and 13 negative tests.
While current guidelines still recommend objective cardiac testing for the evaluation of patients with symptoms concerning for ACS, there is an increasing body of evidence questioning their utility in low-risk patients.3,10–12,35 Testing recommendations are based in large part by the high NPV of stress testing for MACE at 1 year. However, our trial suggests that a similarly high NPV can be achieved by using the HEART Pathway (without objective cardiac testing in low-risk patients). Furthermore, these findings suggest that it may be reasonable for primary care providers and cardiologist to take a less aggressive approach to outpatient objective testing on low-risk HEART Pathway patients seen in follow-up. In addition, our data showed that a large number of patients received multiple objective tests within 1 year. In summation, our data suggest that an opportunity exists to improve the efficiency of outpatient evaluations following an ED visit for chest pain.
There was no statistical difference in 10year cardiac related ED visits and nonindex hospitalizations between patients in the HEART Pathway and usual care arms. Patients identified as low risk by the HEART Pathway infrequently returned to the ED or were hospitalized. This suggests that the concern that the HEART Pathway’s up-front increase in early discharges would increase recidivism is unwarranted. Further, it suggests that higher up-front resource utilization may not provide patients with increased reassurance.
LIMITATIONS
Our trial has several limitations. Small sample size and enrollment from a single center may limit generalizability. Our broad screening methods resulted in a large number of screen failures. In many that were initially screened there was either no concern for ACS or other exclusion criteria were present. Thus the proportion of patients meeting inclusion criteria was small and highly selected. However, patient characteristics and risk factors in our cohort are similar to those found in other ED chest pain studies by our group and other centers.36–38
This study was not powered to detect differences in MACE or small differences in utilization outcomes. However, given prior studies of ED patients with chest pain, we feel that it is unlikely that the safety of the two approaches differs.15,16 Lack of follow-up data on 24 patients (8.5% of participants) may have caused misclassification and underestimation of MACE. However, none of these patients appeared in the Social Security Death Master File. In addition, three deaths were not able to be classified as cardiac or noncardiac, but even if these deaths were considered cardiac related the conclusions of this analysis would be unchanged. Record review and calls were completed concurrently and recorded as complete or incomplete. Data entry on how 1-year follow-ups were completed (i.e., by phone, by record review, or by both methods) was not uniform and not recorded. Finally, more sensitive troponin assays have been approved in the United States. In spite of this limitation, the combination of contemporary serial troponins and the HEART Pathway achieved high sensitivity for detection of MACE at 1 year. The performance of treatment arms combined with high-sensitivity troponin assays at 1 year is unclear.
CONCLUSIONS
The HEART Pathway had 100% sensitivity and negative predictive value for major adverse cardiac events among patients with acute chest pain followed for 1 year. Use of the HEART Pathway did not result in higher downstream recurrent cardiac related ED visits or hospitalizations. While the HEART Pathway reduced objective cardiac testing at 1 year by 8.5% this difference was not statistically significant. The results of this single-center trial require confirmation in a larger multisite study, but they suggest that the HEART Pathway’s predictive abilities may extend beyond the traditional 30-day follow-up period. Our data also suggest that an opportunity exists to improve the efficiency of outpatient objective cardiac testing that occurs following an ED visit for chest pain.
Supplementary Material
Acknowledgments
We want to acknowledge and thank Ashley Moore, Brian Miller, Chelsea Reddeck, Cornelia Hundley, Dylan Flaws, Erin Harper, Erin McLean, Jonathon Bringolf, Justin Doroshenko, Lauren Koehler, Lori Triplett, Maggie Bohannon, Robert Dorrell, Sandeep Yerra, Sarah Posada, Tammy Alley, and Travis Smith for the assistance they provided on this project.
This study was funded by the AHA Clinical Research Program (12CRP12000001 and 13CRP17090055), NHLBI (R01 HL118263, L30 HL120008).
Dr. Mahler also receives research funding from the AAMC/Donaghue Foundation, Duke Endowment, and Roche Diagnostics. Use of Research Electronic Data Capture was supported by the Wake Forest Translational Science Institute via a grant from National Center for Catalysis Research (M01 RR007122). Dr. Mahler and Dr. Stopyra receive research funding from Abbott Point of Care. Dr. Miller receives funding from Siemens by providing software for cardiac imaging research. SAM is the chief medical officer of Impathiq, Inc.
Supervising Editor: Deborah B. Diercks, MS.
Footnotes
Supporting Information
The following supporting information is available in the online version of this paper available at http://onlinelibrary.wiley.com/doi/10.1111/acem.13504/full Data Supplement S1. HEART score.
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