Low Levels of Circulating Troponin as an Intermediate Phenotype in the Pathway to Heart Failure
The following are 10 points to remember about this editorial comment on high-sensitivity troponin T (TnT) measure in heart failure:
1. Low levels of circulating TnT in asymptomatic patients are prognostic, identifying those with either subclinical disease or those at risk for future clinical events.
2. In the general population and those with chronic cardiovascular disease, low levels of TnT likely represent chronic myocardial injury and are very predictive of long-term heart failure risk.
3. Even among patients with myocardial infarction, high TnT levels are better predictive of heart failure events than recurrent infarction.
4. Dose-dependent associations between glycated hemoglobin (HbA1c) levels and TnT levels have been found in patients without documented coronary disease. The editorialists caution that reasons for the associations may be multifactorial and not necessarily causative.
5. Elevations in TnT in those with elevated HbA1c levels could be secondary to reduced renal clearance of TnT in the setting of diabetic nephropathy.
6. It is also possible that hyperglycemia promotes heart failure development through direct myocardial toxicity (rather than atherogenesis). Mechanisms for myocardial injury could include increased oxidative stress, enhanced myocardial fibrosis, and advanced glycation end-products.
7. Early studies have shown that a reduction in circulation TnT levels leads to a lower risk of death and/or heart failure in patients with heart failure or advanced age.
8. No study has shown that reducing TnT levels in asymptomatic ambulatory patients leads to improved outcomes.
9. No study has shown that HbA1C control reduces heart failure development or TnT elevation.
10. There are not enough scientific data at this time to support the use of TnT as an intermediate heart failure phenotype (similar to ACC/AHA stage B heart failure) or as surrogate endpoint for mortality risk.
Keywords: Risk, Myocardial Infarction, Hyperglycemia, Atherosclerosis, Kidney Function Tests, Coronary Disease, Oxidative Stress, Diabetic Nephropathies, Glycosylation End Products, Advanced, Hemoglobin A, Glycosylated, Prognosis, Biological Markers, Phenotype, Heart Failure, Cardiovascular Diseases, Troponin
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