Introduction The British Cardiac Society, in 2004, redefined myocardial infarction by troponin concentration: cTnI ≤0.06 μg/l (unstable angina), cTnI >0.06 μg/l to <0.5 μg/l (myocardial necrosis), and cTnI≥0.5 μg/l (myocardial infarction). We investigated the effects of this classification on all cause mortality.

Methods Survival analysis of 1285 patients from the EMMACE-2 registry.

Results 528 deaths (6.6 year all cause mortality =41.1%). Survival was greatest in the cTnI ≤0.06 μg/l subgroup at 30 days (p=0.005), 6 months (p=0.015), 1 year (p=0.002) and at 6.6 years (p=0.045). After adjustment there was no statistically significant difference in survival between cTnI>0.06 and <0.5 μg/l and cTnI≥0.5 μg/l subgroups. Increased mortality (HR, 95% CI) was associated with ages 70 to 80 years (2.58, 1.17 to 3.91) and >80 years (3.30, 3.50 to 5.06), peripheral vascular disease (1.50, 1.16 to 1.94), heart failure (1.36, 1.05 to 1.83), diabetes (1.68, 1.36 to 2.07), severe LV dysfunction (1.50, 1.00 to 2.21) and creatinine per 10 μmol/l (1.65, 1.02 to 1.08), whereas ages 50 to 60 years (0.55, 0.32 to 0.96), β blockers (0.53, 0.44 to 0.64), aspirin (0.80 0.65 to 0.99), ACE inhibitors (0.67, 0.56 to 0.80), statins (0.73, 0.59 to 0.90) and revascularisation (0.33, 0.12 to 0.92) lowered the risk of death.

Conclusion Quantitative evaluation of cTnI concentration in ACS patients with a cTnI>0.06 μg/l is associated with no added prognostic information. However, the dichotomisation of patients by cTnI status (“positive” and “negative”) continues to facilitate ACS risk stratification.