High-sensitivity troponin: where are we now and where do we go from here?

Incidence and Clinical Impact of Myocardial Injury Following Traumatic Brain Injury: A Pilot TRACK-TBI Study

BACKGROUND

Traumatic brain injury (TBI) is a major global health problem. Little research has addressed extracranial organ dysfunction following TBI, particularly myocardial injury. Using a sensitive marker of myocardial injury-high sensitivity troponin (hsTn)-we examined the incidence of early myocardial injury following TBI and explored its association with neurological outcomes following moderate-severe TBI.

METHODS

We conducted a pilot cohort study of 133 adult (age above 17 y) subjects enrolled in the TRACK-TBI 18-center prospective cohort study. Descriptive statistics were used to examine the incidence of myocardial injury (defined as hsTn >99th percentile for a standardized reference population) across TBI severities, and to explore the association of myocardial injury with a 6-month extended Glasgow Outcome Score among patients with moderate-severe TBI.

RESULTS

The mean (SD) age of the participants was 44 (17) years, and 87 (65%) were male. Twenty-six patients (20%) developed myocardial injury following TBI; myocardial injury was present in 15% of mild TBI patients and 29% of moderate-severe TBI patients (P=0.13). Median (interquartile range) hsTn values were 3.8 ng/L (2.1, 9.0), 5.8 ng/L (4.5, 34.6), and 10.2 ng/L (3.0, 34.0) in mild, moderate, and severe TBI participants, respectively (P=0.04). Overall, 11% of participants with moderate-severe TBI and myocardial injury experienced a good outcome (6-mo extended Glasgow Outcome Score≥5) at 6 months, compared with 65% in the group that did not experience myocardial injury (P=0.01).

CONCLUSIONS

Myocardial injury is common following TBI, with a likely dose-response relationship with TBI severity. Early myocardial injury was associated with poor 6-month clinical outcomes following moderate-severe TBI.

Comparative analysis for the implication of serum cardiac troponin measurements by conventional versus high-sensitivity assays in patients with traumatic brain injury

BACKGROUND

Stress-induced myocardial injury is not well-studied in patients with head injury. We aimed to assess the prognostic implication of positive (+ve) Troponins (Tn) measurements by conventional (cTnT) versus High-Sensitivity (HsTnT) assay in patients with traumatic brain injury (TBI).

METHODS

A retrospective analysis was conducted for patients who were admitted with TBI. Patient demographics, clinical presentation, troponin assay results, TBI lesions, and hospital outcomes were analyzed and compared based on troponin assay (cTnT versus HsTnT).

RESULTS

Across the study period, 654 patients with TBI had troponin levels measured within 24 h postinjury (cTnT=252 and HsTnT=402). The mean age was 31 years and 46% had positive troponins. There were 147 deaths (22.5%); of them 54% had +ve HsTnT, 23% had +ve cTnT, 16% had -ve cTnT and 7% had -ve HsTnT). When the troponins were tested ≤4 h postinjury, the mortality was 10.2% in patients with -ve cTnT and 4% in patients with -ve HsTnT. There was no documented obvious direct trauma to the heart. Overall, patients with positive troponins had lower Glasgow Coma Scale (GCS), higher Injury Severity Scores and higher rates of brain edema (P=0.001), pneumonia and sepsis (P=0.001) than those with negative troponin results. In two different models, multivariate regression analysis showed that +ve cTnT and +ve HsTnT were independent predictors of mortality (OR 4.02, 95% CI: 1.72-9.39) and (OR 4.31; 95% CI: 1.76-10.57); respectively, after adjusting for age, injury severity scores, GCS at ED, head AIS, pneumonia, ARDS, surgical interventions, and chest injury.

CONCLUSIONS

Although the positivity of any troponin assay is associated with high mortality post-TBI, the use of HsTnT relatively outperforms the conventional troponin assay for early risk stratification and detection of stress-induced myocyte injury in patients with TBI.

Self-reported cocaine use is not associated with elevations in high-sensitivity troponin I

OBJECTIVE

High-sensitivity troponin (hsTn) assays detect 10 times lower concentrations of cardiac troponin than conventional assays. We examined the effects of self-reported cocaine use to determine whether those with acute cocaine use being evaluated for ACS are more likely to have elevated hsTnI than those nonusers being evaluated for ACS.

METHODS

We conducted a sub-analysis of a prospective cohort of ED patients evaluated for acute coronary syndrome. Recent cocaine use was determined by structured patient interviews. High-sensitivity troponin (Abbott) and conventional troponin I (Abbott, cTnI) were measured on samples drawn at presentation. Urine toxicology screen for cocaine metabolite was obtained at the discretion of treating clinicians.

RESULTS

Of 1862 patients enrolled, 444 reported prior cocaine use and 99 reported cocaine use within the preceding month. Median hsTn in patients with last cocaine use within 24 h, 2-7 days, 1 week-1 month, >1 month, and no prior cocaine use were: 9 (IQR: 3-17) ng/L, 6 (IQR: 3-24.3) ng/L, 6 (IQR: 3-89.5) ng/L, 3 (IQR: 3-18.5) ng/L and 3 (IQR: 3-17) ng/L, respectively. Urine toxicology assays (UTox) for cocaine were performed in 640 (34.4%) patients. The median hsTn for those who were UTox+, UTox - and those without a UTox were: 9 ng/L (IQR: 3-48.5), 9 ng/L (IQR: 3-40) and 3 ng/L (IQR: 3-12), respectively. There were no differences in the prevalence of new troponin elevations (hsTn >99th percentile but cTnI <99th percentile) in those with recent cocaine use compared to those without recent cocaine use.

CONCLUSIONS

In this first investigation of hsTn in patients with self-reported recent cocaine use, we have determined that hsTn does not lead to an increase in the prevalence of troponin elevation in cocaine users.