High-sensitivity troponin level pre-catheterization predicts adverse cardiovascular outcomes after primary angioplasty for ST-elevation myocardial infarction

Background: Cardiac troponins are the preferred biomarkers for diagnosing myocardial infarction (MI). High-sensitivity troponin T (hs-TnT) assays have increased sensitivity and enable more rapid diagnosis of infarction. We assessed the prognostic utility of admission hs-TnT to detect outcomes after primary angioplasty for ST-elevation/new left bundle branch block myocardial infarction (STEMI).

Methods: Patients admitted to Auckland City Hospital for acute coronary catheterization with a diagnosis of STEMI between October 2010 and September 2011 were identified, and included if hs-TnT levels were measured at admission. Clinical characteristics and major adverse cardiovascular events (MACE: death, myocardial infarction and revascularization) at 30 days and 1 year were collected from national statistics and electronic medical records.

Results: Median admission hs-TnT level in the 173 STEMI patients studied was 59 ng/L (interquartile range (IQR) 19-310). Incidences of MACE at 30 days and 1 year were 10% (n=17) and 18% (n=31), respectively. C-statistics and 95% confidence interval (CI) (95% CI) for hs-TnT on admission at detecting MACE at 30 days and 1 year were 0.800 (0.696-0.904) and 0.750 (0.655-0.845) respectively, with the optimal cut-point of 225 ng/L giving sensitivities/specificities of 76.5%/75.6% and 64.5%/78.2% respectively. Admission log(hs-TnT) independently predicted both MACE at 30 days with hazards ratio 5.16, 95% CI (2.25-11.9) and 1 year with hazards ratio 2.88, 95% CI (1.79-4.63), as did age and cardiogenic shock. Age, Maori or Pacific ethnicity and chronic respiratory disease were independent predictors of hs-TnT>225 ng/L.

Conclusion: Admission hs-TnT measured in primary angioplasty is strongly prognostic of MACE at 30 days and 1 year, even following adjustment for potential confounding variables.