By Martina M. McGrath, MD
February 23, 2017
Cardiac troponins are highly sensitive biomarkers of myocardial injury, and acute rises are a central feature in diagnosis of acute myocardial ischemia. However, observational studies have also suggested that increased levels of high-sensitivity troponin are associated with increased cardiovascular mortality in population-based studies.1,2 This raises the question as to whether the level of high-sensitivity troponin could usefully predict a patient’s future risk of cardiovascular events.
A post-hoc analysis of WOSCOPS (West of Scotland Coronary Prevention Study) published recently in JACC examined the effect of statin therapy on high-sensitivity troponin I (hsTnI) and if these changes could predict future cardiovascular events.3 For this analysis, patients in both treatment arms (pravastatin vs. placebo) were divided by baseline quartiles of troponin. Almost all levels lay within the normal range, with only 1.5% of participants having elevated baseline hsTnI. Those with the highest quartile of troponin concentration were slightly older, with more baseline hypertension, elevated LDL, and EKG abnormalities.
Baseline hsTnI, even within the normal range, was found to be predictive of cardiovascular events. Compared with those with the lowest levels, patients in the highest quartile of troponin concentration were at the greatest risk of cardiovascular death or non-fatal MI; with a doubling of risk at five-year follow-up. Conversely, the patients who showed a decline in troponin concentration by one year experienced a notable reduction in events. Impressively, up to a fivefold reduction in coronary events was observed when troponin decreased to the lowest quartile. Treatment with pravastatin increased the number of patients showing a drop in troponin concentration and these reductions were associated with improved outcomes, independent of LDL cholesterol lowering.
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The authors and editorialists agree that baseline troponin values within the normal range show too much variability to provide risk assessment for individual patients.3,4 However, serial measurements, and monitoring for changes in troponin in response to statin therapy may help to identify those patients responding well or those who remain at elevated cardiovascular risk. These intriguing findings may help to identify a patient population at increased risk of cardiovascular events who need closer monitoring and more intensive intervention to reduce their risk of cardiovascular mortality.
- de Lemos JA, Drazner MH, Omland T, et al. Association of troponin T detected with a highly sensitive assay and cardiac structure and mortality risk in the general population. Jama 2010;304:2503-12.
- Daniels LB, Laughlin GA, Clopton P, Maisel AS, Barrett-Connor E. Minimally elevated cardiac troponin T and elevated N-terminal pro-B-type natriuretic peptide predict mortality in older adults: results from the Rancho Bernardo Study. Journal of the American College of Cardiology 2008;52:450-9.
- Ford I, Shah AS, Zhang R, et al. High-Sensitivity Cardiac Troponin, Statin Therapy, and Risk of Coronary Heart Disease. Journal of the American College of Cardiology 2016;68:2719-28.
- Jaffe AS, Wright RS. High-Sensitivity Cardiac Troponin and Primary Prevention: An Important New Role. Journal of the American College of Cardiology 2016;68:2729-32.
Dr. Martina McGrath is an Instructor in Medicine at Harvard Medical School, and a member of the Renal Division, Department of Medicine, at Brigham and Women’s Hospital, both in Boston. Dr. McGrath is the Medical Editor for the Trends in Medicine blog