Trends in admissions for chest pain after the introduction of high-sensitivity cardiac troponin T☆

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Abstract

Background

The aim was to describe temporal trends in admission rates for chest pain and patient outcomes after the clinical introduction of the high-sensitivity cardiac troponin T (hs-cTnT) assay.

Methods

We included all patients aged > 25 years presenting with chest pain to the emergency department (ED) at our hospital during 2011–2014. For each year, rates of admissions, coronary angiographies, and revascularizations were determined. After adjustment for confounders, hazard ratios (HR) with 95% confidence intervals (CI) were calculated for mortality or major adverse cardiac events (MACE) within 1 year of the ED visit per year, using 2011 as referent.

Results

In total, 15,472 chest pain patients were accountable for 18,237 visits to the ED. The chest pain admission rate in 2011 was 44%; 2012, 39%; 2013, 33%; and 2014, 28%, with an overall decrease in 36%. Coronary angiographies within 1 year of the ED visit increased from 6.8% in 2011 to 9.6% in 2013, but the proportion of revascularizations was virtually unchanged. The risk of death within 1 year of the visit increased by 51% (HR 1.51, 95% CI, 1.18–1.92) in 2014, compared with 2011. Only non-cardiovascular mortality was significantly increased (HR 1.85, 95% CI, 1.34–2.55), with no increase in MACE.

Conclusion

Admissions for chest pain were reduced by 36% the first 4 years of hs-cTnT use. We observed no increase in MACE, but all-cause mortality increased significantly for non-cardiovascular causes only which was paralleled by a significant increase in the use of coronary angiographies.

Introduction

Clinical suspicion of myocardial infarction (MI) is one of the leading causes of hospital admissions in Europe and the USA [1]. The evaluation of patients presenting with chest pain to the emergency department (ED) is based on clinical signs and symptoms, electrocardiograms (ECG), and cardiac biomarkers to determine if they should be admitted for observation or discharged to their homes [2]. The recent clinical introduction of high-sensitivity cardiac troponin (hs-cTn) assays has enabled an earlier detection of cardiac ischemia in chest pain patients, leading to a shorter evaluation time in the ED [3], [4].

The sensitivity improvement offered by the hs-cTn assays does not come without a cost. More patients without MI will have elevated troponin levels (above the so called 99th percentile) given the lower specificity [5], [6]. Introduction of the hs-cTn assays may increase hospital admissions for chest pain as well as the downstream resource utilization, which has raised some concerns [7].

The effects of hs-cTn assays on admission rates for chest pain during the first few years of introduction are largely unknown. Therefore, we sought to determine temporal trends of admission rates. Additionally, we evaluated the effect on coronary angiographies, revascularizations, and outcomes after the introduction of the hs-cTnT assay in December 2010, at our hospital.

Section snippets

Study population

From the hospital's local emergency attendance register, we identified all patients aged above 25 years, who visited the ED at the Karolinska University Hospital, Huddinge, Sweden with chest pain as the principal complaint from 1 January 2011 to 20 October 2014. During the study period, the ED had around 75,000 yearly visits by adult patients. Abdominal pain was the most common reason for the visit, followed by chest pain and dyspnea.

Study design

Through the hospital's technical department, we combined

Patient characteristics

Characteristics of the study population and number of visits were similar during the whole study period (Table 1). Patients had a similar age, and only small differences in comorbidities, as well as cardiovascular medication over time. The proportion of patients with undetectable hs-cTnT levels changed substantially from 62% in 2011 to 42% in 2014 owing to the lower sensitivity of the early batches of reagents that were used for the hs-cTnT assay until April 2012 [10]. The change in the

Discussion

In a cohort of 15,472 patients who visited the ED with chest pain as the principal complaint, we found that the hospital admission rate was reduced by 36% during the 4 years following the introduction of hs-cTnT. There was an increase in resource utilization in terms of coronary angiographies and cardiac revascularizations. Additionally, we found an increased risk of non-cardiovascular mortality, but cardiovascular mortality was unchanged during the study period.

Conclusions

We found that during the first 4 years after the introduction of hs-cTnT, there was a 36% decrease in hospital admissions for chest pain. This decrease was associated with an increase in non-cardiovascular mortality, which was only significant in patients with hs-cTnT levels > 14 ng/l. Furthermore, there was a significant increase in the rate of coronary angiographies performed.

The following are the supplementary data related to this article.

Contributors

All authors had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. MJH and RL contributed to the study design while MJH and NB contributed to the acquisition of data. All authors contributed to the analysis and interpretation of data, and critically revised the manuscript for important intellectual content. NB and MJH drafted the manuscript. MJH obtained funding for the study and provided administrative,

Funding

The study was funded by the Swedish Society of Medicine (grant, SLS-409991), the Swedish Heart-Lung Foundation (grants, 20150594 and 20150603), and the Stockholm County Council (grant, 20150265). The sponsors had no role in the design or conduct of this study.

Disclosures

None.

Conflict of interest

There was no conflict of interest.

Acknowledgements

We wish to express our gratitude to Fredrik Mattsson at FM Statistikkonsult for his assistance with data management and statistical analyses.

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