Article Text
Abstract
Objective: To assess the impact on observed mortality of the British Cardiac Society (BCS) definition of myocardial infarction (MI) in 11 UK hospitals.
Design: Prospective observational registry.
Setting: 11 adjacent hospitals in the West Yorkshire region.
Patients: 2484 patients with the acute coronary syndrome (ACS) were identified during a six month period (28 April to 28 October 2003). Demographic, clinical, and treatment variables were collected on all patients. Deaths were monitored through the Office of National Statistics. Patients were categorised into three groups according to the BCS definition of MI: ACS with unstable angina (UA), ACS with myocyte necrosis, and ACS with clinical MI.
Results: 30 day mortality was 4.5%, 10.4%, and 12.9% (p < 0.001) in the ACS with UA, ACS with myocyte necrosis, and ACS with clinical MI groups, respectively. At six months the mortality for patients in the groups ACS with clinical MI and ACS with myocyte necrosis was similar (19.2% v 18.7%), being higher than for ACS with UA (8.6%). Same admission percutaneous coronary intervention was similar in groups with clinical MI and myocyte necrosis (11.1% v 10.7%, respectively) as was coronary artery bypass grafting (2.6% v 2.7%, respectively). However, these two groups differed significantly in the prescribing of secondary prevention (aspirin, 79% v 69%; statins, 80% v 68%; β blockers, 66% v 53%; and angiotensin converting enzyme inhibitors, 65% v 53%; p < 0.001).
Conclusions: At 30 days the new BCS categories for MI predict three distinct outcomes. However, within a contemporary UK population this was no longer apparent at six months, as mortality for patients with ACS with myocyte necrosis had risen to the same level as those for patients with ACS with clinical MI. One possible explanation for this is the apparent under use of drugs known to improve prognosis after traditionally defined MI.
- ACC, American College of Cardiology
- ACE, angiotensin converting enzyme
- ACS, acute coronary syndrome
- BCS, British Cardiac Society
- CK, creatine kinase
- CV, coefficient of variation
- EMMACE-2, evaluation of methods and management of acute coronary events
- ESC, European Society of Cardiology
- FRISC-II, Fragmin and fast revascularisation during instability in coronary artery disease
- GRACE, global registry of acute coronary events
- MI, myocardial infarction
- NSTEMI, non-ST elevation myocardial infarction
- PCI, percutaneous coronary intervention
- STEMI, ST elevation myocardial infarction
- TACTICS, treat angina with Aggrastat and determine cost of therapy with invasive or conservative strategy
- UA, unstable angina
- WHO, World Health Organization
- acute myocardial infarction
- prognosis
- acute coronary syndrome
- epidemiology
- guidelines
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- ACC, American College of Cardiology
- ACE, angiotensin converting enzyme
- ACS, acute coronary syndrome
- BCS, British Cardiac Society
- CK, creatine kinase
- CV, coefficient of variation
- EMMACE-2, evaluation of methods and management of acute coronary events
- ESC, European Society of Cardiology
- FRISC-II, Fragmin and fast revascularisation during instability in coronary artery disease
- GRACE, global registry of acute coronary events
- MI, myocardial infarction
- NSTEMI, non-ST elevation myocardial infarction
- PCI, percutaneous coronary intervention
- STEMI, ST elevation myocardial infarction
- TACTICS, treat angina with Aggrastat and determine cost of therapy with invasive or conservative strategy
- UA, unstable angina
- WHO, World Health Organization
Footnotes
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Published Online First 14 April 2005
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Funding: This work funded by educational grants from Astra Zeneca and Beckman Coulter Ltd. RD and NK held British Heart Foundation Junior Research Fellowships.
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No competing interests.
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Ethical approval: The study was approved by the Eastern Multi-Research Ethics Committee and the Local Research Ethics Committees within West Yorkshire.