High-Sensitivity Cardiac Troponins I and T and Cardiovascular Outcomes: Findings from the Systolic Blood Pressure Intervention Trial (SPRINT)

BACKGROUND: Cardiac troponins are associated with adverse cardiovascular disease (CVD) outcomes. The value of high-sensitivity cardiac troponin I (hs-cTnI) independently and in concert with troponin T (hs-cTnT) in the management of hypertension has not been well studied. METHODS: We assessed the utility of hs-cTnI independently and with hs-cTnT in identifying the highest risk individuals in the Systolic Blood Pressure Intervention Trial (SPRINT). Among 8796 eligible SPRINT participants, hs-cTnI was measured at baseline and 1 year. The association of baseline level and 1-year change in hs-cTnI with CVD events and all-cause death was evaluated using adjusted Cox regression models. We further assessed the complementary value of hs-cTnI and hs-cTnT by identifying concordant and discordant categories and assessing their association with outcomes. RESULTS: hs-cTnI was positively associated with composite CVD risk [myocardial infarction, other acute coronary syndrome, stroke, or cardiovascular death: hazard ratio 1.23, 95% confidence interval 1.08.1.39 per 1-unit increase in log(troponin I)] independent of traditional risk factors, N-terminal pro-B-type natriuretic peptide, and hs-cTnT. Intensive blood pressure lowering was associated with greater absolute risk reduction (4.5% vs 1.7%) and lower number needed to treat (23 vs 59) for CVD events among those with higher baseline hs-cTnI (≥6 ng/L in men, ≥4 ng/L in women). hs-cTnI increase at 1 year was also associated with increased CVD risk. hs-cTnI and hs- cTnT were complementary, and elevations in both identified individuals with the highest risk for CVD and death. CONCLUSIONS: Baseline levels and change in hs-cTnI over 1 year identified higher-risk individuals who may derive greater cardiovascular benefit with intensive blood pressure treatment. hs-TnI and hs-TnT have complementary value in CVD risk assessment.