The British Cardiac Society Working Group definition of myocardial infarction: implications for practice.
OBJECTIVE
To assess the impact on observed mortality of the British Cardiac Society (BCS) definition of myocardial infarction (MI) in 11 UK hospitals.


METHODS
Prospective observational registry.


METHODS
11 adjacent hospitals in the West Yorkshire region.


METHODS
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%; beta 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.
Das
R
R
British Heart Foundation Heart Research Centre, Leeds General Infirmary, Leeds, UK.
Kilcullen
N
N
Morrell
C
C
Robinson
M B
MB
Barth
J H
JH
Hall
A S
AS
D000368:Aged; D004739:England / Q000453:epidemiology; D017052:Hospital Mortality; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D009203:Myocardial Infarction / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy; D009206:Myocardium / Q000473:pathology; D009336:Necrosis; D011379:Prognosis; D011446:Prospective Studies; D016019:Survival Analysis