The declining prevalence of ST elevation myocardial infarction in patients presenting with acute coronary syndromes

Obesity and cardiovascular outcomes: a review

The prevalence of obesity is increasing at an epidemic rate globally with more than 1 billion adults overweight and at least 300 million of them clinically obese. This is expected to rise further in the next 20 to 30 years. Obesity is known to be an independent risk factor for serious health conditions, including hypertension, type 2 diabetes, and cardiovascular diseases. Given the association of obesity with cardiovascular disease, it could be speculated that obese individuals would have adverse outcomes after a cardiovascular event compared to those with normal body mass index (BMI). However, various studies have reported a paradoxical U-shaped relationship between obesity and mortality from various diseases, including myocardial infarction and heart failure, suggesting that patients with higher BMI have similar or lower short- and long-term mortality rates. This phenomenon has been termed the 'obesity paradox' or 'reverse epidemiology'. The goal of this review is to evaluate the potential mechanisms behind the obesity paradox and its implications.

Identification of myocardial injury in the emergency setting

Within the past decade, the use of biomarkers to detect myocardial injury in the emergency department (ED) has been given increasing prominence as evident by the numerous studies and guidelines documenting their use. This review details the scope of the clinical problem, the history of changes in the definition of myocardial infarction (MI) and the new approaches, as well as suggestions for using laboratory biomarkers in the early detection of MI in the ED.

Diabetes mellitus and mortality after acute coronary syndrome as a first or recurrent cardiovascular event

Background

Diabetes Mellitus (DM) is associated with adverse cardiovascular prognosis. However, the risk associated with DM may vary between individuals according to their overall cardiovascular risk burden. Therefore, we aimed to determine whether DM is associated with poor outcome in patients presenting with Acute Coronary Syndrome (ACS) according to the index episode being a first or recurrent cardiovascular event.

Methods and Findings

We conducted a retrospective analysis of a prospective cohort study involving 2499 consecutively admitted patients with confirmed ACS in 11 UK hospitals during 2003. Usual care was provided for all participants. Demographic factors, co-morbidity and treatment (during admission and at discharge) factors were recorded. The primary outcome was all cause mortality (median 2 year follow up), compared for cohorts with and without DM according to their prior cardiovascular disease (CVD) disease status. Adjusted analyses were performed with Cox proportional hazards regression analysis. Within the entire cohort, DM was associated with an unadjusted 45% increase in mortality. However, in patients free of a history of CVD, mortality of those with and without DM was similar (18.8% and 19.7% respectively; p = 0.74). In the group with CVD, mortality of patients with DM was significantly higher than those without DM (46.7% and 33.2% respectively; p<0.001). The age and sex adjusted interaction between DM and CVD in predicting mortality was highly significant (p = 0.002) and persisted after accounting for comorbidities and treatment factors (p = 0.006). Of patients free of CVD, DM was associated with smaller elevation of Troponin I (p<0.001). However in patients with pre-existing CVD Troponin I was similar (p = 0.992).

Conclusions

DM is only associated with worse outcome after ACS in patients with a pre-existing history of CVD. Differences in the severity of myocyte necrosis may account for this. Further investigation is required, though our findings suggest that aggressive primary prevention of CVD in patients with DM may have beneficially modified their first presentation with (and mortality after) ACS.

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

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.

Earlier detection of myocardial infarction by an improved cardiac TnI assay

OBJECTIVES

The aim of this study was to establish the diagnostic sensitivity of combinations of well-selected monoclonal antibodies (mAbs) against cardiac troponin I (cTnI) to allow an earlier rule-in of acute coronary syndrome (ACS) patients.

DESIGN AND METHODS

Using several combinations of mAbs, four new experimental cTnI immunoassays were evaluated to analyze plasma samples from 62 patients suffering from angina (16/62), patients having a chest pain of extracardiovascular origin (19/62) and ACS without ST elevation (NSTE-ACS) (27/62).

RESULTS

Assay 2, which relies on a capture mAb directed against the central part of cTnI and two conjugated mAbs directed against the N-ter region, provided the best clinical sensitivity. In 11 out of 27 patients with NSTE-ACS, it detected an early rise of cTnI within 0 and 1 h upon admission, contributing to the detection of 53% of samples found to be negative by the reference AccuTnI Assay upon admission (Beckman Coulter), thereby reducing the delay in diagnosis.

CONCLUSIONS

Assay 2 can identify early cTnI elevation in NSTE-ACS, possibly facilitating the rule-in procedure for these patients once the assay is automated.

Electrocardiographic diagnosis of non–ST-segment elevation acute coronary syndromes: current concepts for the physician

With several myocardial infarction (MI) registries reporting a decline in the incidence of ST-elevation MI (STEMI) and an increase in non-ST-elevation MI (NSTEMI) and unstable angina (UA), it is important that future healthcare resources are directed towards this increased volume of patients, ECG technology, core to the early diagnosis of these patients, has lagged behind relative to other techniques and little progress has been as far as acute coronary syndrome triage is concerned beyond ST-segment deviation. We present a review of the literature on current electrocardiographic changes which will allow admitting physicians to better risk stratify those patients with "non-diagnostic ECGs." These ECGs may become diagnostic with careful evaluation, use of serial ECGs and when additional lead sets are used.