Original article
A description of the characteristics of patients with non-ST elevation acute coronary syndromes admitted to different settings in the 1990s

https://doi.org/10.1016/j.iccn.2008.01.005Get rights and content

Summary

Background

Little is known about the characteristics of patients who were admitted to the coronary care unit (CCU) in the 1990s with non-ST elevation acute coronary syndromes (ACS) compared with those admitted to medical and cardiology wards in hospitals in the United Kingdom (UK).

Aim

To understand if there were systematic differences in the characteristics of patients who were admitted to UK critical care units (CCU), intermediate care environments (cardiology wards) or generalist wards (acute medical ward) in an observational study carried out in the 1990s.

Methods

This paper is based on a secondary analysis of PRAIS (UK), a prospective, observational, multi-centred study which recruited 1038 patients with non-ST elevation ACS. This analysis compares the characteristics of 860 of these patients dependent on whether they were cared for in a coronary care unit, acute medical ward or cardiology ward.

Results

The results showed that patients admitted to CCU were more likely to be younger, male, have a history of diabetes or have ST depression on their ECG. There was very little difference in other risk factors or prior concomitant therapy. Interestingly there were no systematic differences in treatments or outcomes other than would be expected by chance, although there were trends to higher rates of MI and heart failure in the CCU group.

Conclusion

Our analysis shows that the main drivers of admission to CCU in the 1990s were ST depression and MI—both indicators of high risk, but older age and female gender seemed to decrease the likelihood of admission to CCU. Criteria for admission to specific specialist and non-specialist care environments should be standardised and the use of risk scores could be an important way forward.

Introduction

Coronary care units (CCUs) were first developed in the 1960s to cater for the needs of patients with potentially life threatening cardiac conditions. In reality these facilities were used mainly for patients with acute myocardial infarction (AMI). Indeed it has been argued (Braunwald, 1998) that the CCU is the most important advance in the treatment of ST elevation MI. However more recently CCUs have been used for a wider group of patients including non-ST elevation acute coronary syndromes, severe arrhythmia and advanced heart failure.

The PRAIS (UK) study (Collinson et al., 2000) provided information on the characteristics and outcomes of patients with non-ST elevation acute coronary syndromes. However little is known about the differences in the characteristics of the patients who are admitted to highly resourced intensive care environments, e.g. CCU compared with those admitted to less intense care settings such as cardiology wards and general medical wards in the UK.

With the increased prevalence of non-ST elevation acute coronary syndromes in comparison with a reduction in prevalence of ST elevation MI (Kleiman and White, 2005) we analysed the characteristics of patients admitted to CCUs compared to other ward areas in the PRAIS-UK patient population.

Whilst these data relate to the late 1990s we felt that this information would provide a historical overview of care upon which more contemporary studies could draw comparisons when studying the evolution of cardiac care.

Section snippets

Methods

This investigation conforms with the principles outlined in the declaration of Helsinki and describes the results of a secondary analysis of the PRAIS (UK) study (Collinson et al., 2000). The study was approved by the UK Multi-Centre Research Ethics Committee, Local Research Ethics Committees and all patients gave their written informed consent prior to taking part in the study.

The original PRAIS (UK) study (Collinson et al., 2000) was undertaken as a prospective observational cohort registry

Baseline characteristics of patients compared by clinical setting

There were a number of statistically significant differences between the groups at baseline (Table 1). For example we discovered the proportion of male patients admitted to the CCU, cardiology ward and general medical ward were 66.4%, 57.3%, 54.1%, respectively. CCU patients were more likely to have a diagnosis of MI (8.4%, 4.8%, 1.6%) or diabetes (19.4%, 13.7%, 10.7%) or have ST depression on their admission ECG (25.2%, 18.3%, 13.1%) (Fig. 1). Conversely, patients presenting with a normal ECG

Discussion

Our study shows that patients admitted to CCU had certain higher risk features than those admitted to other ward areas, including ST depression and diabetes but also CCU patients were slightly younger and more likely to be male. There did not appear to be a systematic approach to deciding whether a patient should go to a particular care setting but the clearest trends favouring CCU admission were ECG ischaemia severity and the presence of diabetes.

Conversely, patients presenting with a normal

Acknowledgements

To the team at the Clinical Trials Unit at the Royal Brompton Hospital who were the author of the PRAIS (UK) study upon which this secondary analysis was based. Without their willingness to share these data this study would not have been possible.

References (29)

  • J. Collinson et al.

    Clinical outcomes, risk stratification and practice patterns of unstable angina and myocardial infarction without ST elevation: prospective registry of acute ischaemic syndromes in the UK (PRAIS-UK)

    Eur Heart J

    (2000)
  • J. Collinson et al.

    Managing high risk patients with acute coronary syndromes: the prospective registry of acute ischaemic events syndromes in the UK (PRAIS-UK)

    Clin Med

    (2004)
  • N.J. Dudley et al.

    The influence of age on policies for admission and thrombolysis in coronary care units in the United Kingdom

    Age Ageing

    (1992)
  • K.A. Eagle et al.

    A validated prediction model for all forms of acute coronary syndrome. Estimating the risk of 6 month post discharge death in an international registry

    J Am Med Assoc

    (2004)
  • 1

    Tel.: +44 207 352 8121.

    2

    Tel.: +44 161 295 5000.

    View full text