Elsevier

Resuscitation

Volume 79, Issue 1, October 2008, Pages 41-45
Resuscitation

Clinical paper
Do risk factors for chronic coronary heart disease help diagnose acute myocardial infarction in the Emergency Department?☆

https://doi.org/10.1016/j.resuscitation.2008.06.009Get rights and content

Summary

Background

Hypertension, hyperlipidaemia, diabetes mellitus, tobacco smoking and a family history of premature coronary artery disease are known to be risk factors for the development of coronary artery disease. We sought to determine whether these traditional risk factors aid the diagnosis of acute myocardial infarction (AMI) in the Emergency Department (ED).

Methods

We performed a prospective diagnostic cohort study within the ED at Manchester Royal Infirmary, a university-affiliated teaching hospital with an annual ED census of approximately 145,000 patients. We recruited 804 patients who had presented to the ED with suspected cardiac chest pain. All patients had the presence or absence of traditional cardiac risk factors documented at the time of presentation using a custom-designed clinical report form. All patients subsequently underwent 12-h troponin T testing to provide a robust gold standard for the diagnosis of AMI according to revised World Health Organisation criteria.

Results

The absence of any traditional cardiac risk factors carried a negative likelihood ratio of 0.61 for the diagnosis of AMI. 12.2% of patients with no cardiac risk factors had AMI, compared with 21.3% of patients with four or five risk factors. The area under the receiver-operating characteristic curve was 0.49.

Conclusions

Traditional cardiac risk factors are not helpful for the confirmation or exclusion of AMI within the ED. Future Emergency Medicine research should focus on those clinical and diagnostic features that are likely to alter during the acute phase of illness.

Section snippets

Background

The Framingham Heart Study played a vital role in identifying important risk factors for the development of coronary heart disease.1 These included hypertension,2, 3 hyperlipidaemia,2, 4 tobacco smoking,3, 4, 5, 6 diabetes mellitus7, 8, 9 and a family history of premature coronary artery disease.10 While it is apparent that each of these risk factors predisposes an individual to the development of coronary heart disease, the precise role of these risk factors in confirming or excluding acute

Study design and setting

This is a substudy of the Early Vascular Markers of Acute Coronary Syndromes (EVaMACS) study, a single-centre prospective diagnostic cohort study. The study was approved by the Local Research Ethics Committee. All patients provided written informed consent. We recruited patients at Manchester Royal Infirmary, a university-affiliated teaching hospital. The annual ED census is approximately 145,000 (comprising approximately 39,000 cases triaged to ‘Majors’ including the Resuscitation Room and

Results

804 patients were recruited to the study between January 2006 and February 2007. Eight patients were excluded because they were found to meet pre-defined exclusion criteria, meaning that 796 patients were suitable for final analysis. 148 (18.6%) patients had AMI. There was no missing data regarding the presence or absence of cardiac risk factors in any patient. All patients underwent troponin T testing ≥12 h after the onset of their most significant symptoms. No patients were lost to follow up

Discussion

Our results indicate that traditional cardiac risk factors do not assist in the diagnosis or exclusion of AMI within the ED. Of the five traditional risk factors only smoking was a significant positive predictor of the diagnosis of AMI. While the absence of any cardiac risk factors has slight negative predictive value, a likelihood ratio of 0.61 means that in our population with a 18.6% incidence of AMI (a similar incidence to other similar studies14) the post-test probability of AMI is shifted

Conclusions

Risk factors for chronic coronary heart disease are not clinically helpful in the diagnosis or exclusion of AMI in the ED setting. Future Emergency Medicine research should focus upon factors that are likely to alter during the acute phase of illness.

Conflict of interest

The authors confirm that they have no conflicts of interest to declare with regard to this study.

Acknowledgements

The authors would like to acknowledge the contribution of Dr. Jamie Ferguson, who assisted with patient recruitment and follow up and research administration. We would also like to acknowledge the assistance given by all of the nursing and medical staff in the Emergency Department at Manchester Royal Infirmary.

Study sponsors: The study was sponsored by Central Manchester & Manchester Children's NHS Trust, who played no role in data analysis or the decision to submit the manuscript for

References (18)

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☆

A Spanish translated version of the summary of this article appears as Appendix in the online version at doi:10.1016/j.resuscitation.2008.06.009.

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