Troponin Blood Test May Minimize Hospitalization

A new study shows that using a high-sensitivity cardiac troponin I (cTnI) assay can halve the number of people admitted to hospital with a suspected myocardial infarction (MI).

Researchers at the University of Edinburgh (United Kingdom), Hennepin County Medical Center (Minneapolis, MN, USA), and other institutions conducted a prospective cohort study of 6,304 patients with suspected acute coronary syndrome presenting to four secondary and tertiary care hospitals in Scotland. The researchers measured plasma cTnI concentrations at presentation and evaluated the negative predictive value of a range of troponin concentrations for MI, subsequent MI, or cardiac death at 30 days.

The results showed that low plasma cTnI concentrations could identify two-thirds of patients at very low risk of cardiac events who could be discharged from hospital. In patients without MI at presentation, troponin concentrations were less than 5 ng/L in 61% of the patients, with a negative predictive value of 99.6% consistent across groups stratified by age, sex, risk factors, and previous cardiovascular disease. At one year, these patients had a lower risk of MI and cardiac death than did those with a cTnI concentration of 5 ng/L or more. The study was published on October 7, 2015, in the Lancet.

“Our study shows that low heart troponin concentrations identify up to two-thirds of patients who are at very low risk of heart attack and could be safely discharged,” said lead author Anoop Shah, MD, and colleagues of the BHF Centre for Cardiovascular Science at the University of Edinburgh. “These findings could dramatically reduce unnecessary hospital admissions and potentially save the National Health Service millions, as it can reduce unnecessary emergency admissions.”

Cardiac troponin T (cTnT) and troponin I (cTnI) are regulatory proteins that control the calcium mediated interaction between actin and myosin. The cardiac forms of these regulatory proteins are coded by specific genes and theoretically have the potential of being unique to the myocardium. The measurement of serum cTnI and cTnT is superior in terms of sensitivity and specificity to cardiac muscle enzyme measurements in the identification of cardiac muscle damage, currently accepted as the standard biochemical marker for the diagnosis of MI.

Related Links:
University of Edinburgh
Hennepin County Medical Center