Everett, Brendan M.

Background: Circulating cardiac troponin T concentrations are higher in men than in women, but the biological causes and clinical implications of this observation are poorly understood. Methods and Results: We measured cardiac troponin T with a high-sensitivity assay (hsTnT) in 684 women and 1601 men with type 2 diabetes (T2D) and stable ischemic heart disease (SIHD) who were enrolled in the BARI 2D trial. Median (IQR) hsTnT was higher in men [12.4 ng/L (8.7-20.8)] than in women [9.1 ng/L (6.4-15.6); P<0.0001] and a higher proportion of men (43.6%) than women (29.1%) were above the current established upper reference limit of 14 ng/L (P<0.0001). Sex remained a significant predictor of natural log normalized hsTnT after adjusting for a wide array of covariables, including age, race, insulin use, renal function, ejection fraction, and HbA1c. Within quintiles of hsTnT measured at baseline, the 5-year incidence of the composite cardiovascular outcome of myocardial infarction, stroke, heart failure, or death was consistently higher in women than in men (Figure 1). In sex-stratified Cox models adjusting for possible confounders, the increase in the relative risk of the composite endpoint across quintiles of hsTnT appeared similar in men and women (Figure 2). Conclusions: In the BARI 2D trial, women have lower baseline hsTnT concentrations, but higher absolute risk of myocardial infarction, stroke, heart failure, or death for a given concentration of hsTnT. These data raise the question of whether sex-specific cutoffs for cardiac troponin T should be considered.

Background: In spite of aggressive preventive therapy, patients with type 2 diabetes (T2D) and stable ischemic heart disease (SIHD) remain at high risk for major cardiovascular events and death. Understanding the pathophysiologic determinants of that residual risk could help identify effective preventive therapies. Methods and Results: In this Ancillary Study of the BARI 2D trial, we examined the predictive value of biomarkers from 6 distinct pathophysiologic pathways in 2285 men and women with T2D and SIHD who were followed for a median (IQR) of 5.0 (4.1-6.0) years. The endpoint for this Ancillary Study was a composite of myocardial infarction, stroke, heart failure, or all-cause mortality. The 5-year Kaplan-Meier event rate was 31%. The pathophysiologic processes evaluated included dysglycemia (HbA1c), dyslipidemia (LDL-C), myocardial strain (NT-proBNP), myocardial injury (high-sensitivity cardiac troponin T [hsTnT]), subclinical inflammation (high-sensitivity C-reactive protein [hsCRP]), and nephropathy (presence/absence of macroalbuminuria). In Cox proportional hazards models adjusted for baseline risk factors, angiographic severity of disease, and ejection fraction, each marker except LDL-C was a significant predictor of outcome (Figure) in this population with 74% baseline statin use. After mutual adjustment for all 6 markers and baseline risk factors, the hazard ratio (95% CI) per 1-SD of natural logarithm transformed concentration was largest for NT-proBNP [1.29 (1.17, 1.42)], followed by hsTnT [1.16 (1.07, 1.26)], HbA1c [1.12 (1.03, 1.21)], and hsCRP [1.11 (1.03, 1.20). Macroalbuminuria was not a significant predictor after adjustment for the other markers (Figure). Conclusions: In this high-risk population of patients with type 2 diabetes and stable ischemic heart disease, strategies to target myocardial strain, myocardial injury, and subclinical inflammation may lead to improvements in cardiovascular outcome.

AbstractBACKGROUNDIncreased cardiac troponin I or T detected by high-sensitivity assays (hs-cTnI or hs-cTnT) confers an increased risk of adverse prognosis. We determined whether patients presenting with putatively normal, detectable cTn concentrations [&gt; limit of detection and &lt; upper reference limit (URL)] have increased risk of major adverse cardiovascular events (MACE) or all-cause mortality.METHODSA prospective 5-year follow-up of patients recruited in the emergency department with possible acute coronary syndrome (ACS) and cTn concentrations measured with hs-cTnI (Abbott) and hs-cTnT (Roche) assays. Cox regression models were generated with adjustment for covariates in those without MACE on presentation. Hazard ratios (HRs) for hs-cTn were calculated relative to the HRs at the median concentration.RESULTSOf 1113 patients, 836 were without presentation MACE. Of these, 138 incurred a MACE and 169 died during a median 5.8-year follow-up. HRs for MACE at the URLs were 2.3 (95% CI, 1.7–3.2) for hs-cTnI and 1.8 (95% CI, 1.3–2.4) for hs-cTnT. Corresponding HRs for mortality were 1.7 (95% CI, 1.2–2.2) for hs-cTnI and 2.3 (95 % CI, 1.7–3.1) for hs-cTnT. The HR for MACE increased with increasing hs-cTn concentration similarly for both assays, but the HR for mortality increased at approximately twice the rate for hs-cTnT than hs-cTnI. Patients with hs-cTnI ≥10 ng/L or hs-cTnT ≥16 ng/L had the same percentage of MACE at 5-year follow-up (33%) as patients with presentation MACE.CONCLUSIONSMany patients with ACS ruled out and putatively normal but detectable hs-cTnI concentrations are at similar long-term risk as those with MACE. hs-cTnT concentrations are more strongly associated with 5-year mortality than hs-cTnI.