Distribution of High-Sensitivity Troponin Taken Without Conventional Clinical Indications in Critical Care Patients and Its Association With Mortality

Prognostic value of high-sensitivity cardiac troponin in non-cardiac surgical patients in intensive care units

Type II myocardial injury following surgical procedures is associated with adverse outcomes. The prognostic value of high-sensitivity cardiac troponin (hs-cTn) due to type II myocardial injury in surgical patients admitted to intensive care unit (ICU) remains unclear. The aim of this study was to assess prognostic value of hs-cTn in type II acute myocardial injury in non-cardiac surgical patients requiring post-operative ICU admission. Retrospective analysis of patients admitted to two level III ICUs following surgery and had hs-cTn measured on the day of ICU admission. Patients who had type I acute myocardial infarction (AMI) during their admission were excluded from the study. The primary outcome was hospital mortality. Secondary outcomes included ICU mortality, ICU length of stay (LOS) and hospital LOS. A total of 420 patients were included. On univariable analysis, higher hs-cTn was associated with increased hospital mortality (14.6% vs 6.3%, p = 0.008), ICU LOS (41.1 h, vs 25 h, p = 0.004) and hospital LOS (253 h vs 193 h, p = 0.02). On multivariable analysis, hs-cTn was not independently associated with increased risk of hospital mortality. However, in patients who had elective surgery, hs-cTn was associated with increased risk (OR 1.048; 95% CI 1.004-1.094; p = 0.031) of hospital mortality with area under the receiver operating characteristic curve of 0.753 (95% CI 0.598-0.908). In elective surgical patients, hs-cTn was associated with increased risk of mortality. Larger multicentre studies are required to confirm this association that may assist in risk stratification of elective surgical patients requiring ICU admission.

Association between troponin level and medium-term mortality in 20 000 hospital patients

INTRODUCTION

Cardiac troponin (cTn) concentrations above the manufacturer recommended upper limit of normal (ULN) are frequently seen in hospital patients without a clinical presentation consistent with type 1 myocardial infarction, and the significance of this is uncertain. The aim of this study was to assess the relationship between medium-term mortality and cTn concentration in a large consecutive hospital population, regardless of whether there was a clinical indication for performing the test.

METHOD

This prospective observational study included 20 000 consecutive in-hospital and outpatient patients who had a blood test for any reason at a large teaching hospital, and in whom a hs-cTnI assay was measured, regardless of the original clinical indication. Mortality was obtained via NHS Digital.

RESULTS

A total of 20 000 patients were included in the analysis and 18 282 of these (91.4%) did not have a clinical indication for cardiac troponin I (cTnI) testing. Overall, 2825 (14.1%) patients died at a median of 809 days. The mortality was significantly higher if the cTnI concentration was above the ULN (45.3% vs 12.3% p<0.001 log rank). Multivariable Cox analysis demonstrated that the log10 cTnI concentration was independently associated with mortality (HR 1.76 (95% CI 1.65 to 1.88)). Landmark analysis, excluding deaths within 30 days, showed the relationship between cTnI concentration and mortality persisted.

CONCLUSION

In a large, unselected hospital population, in 91.4% of whom there was no clinical indication for testing, cTnI concentration was independently associated with medium-term cardiovascular and non-cardiovascular mortality in the statistical model tested.

The Relationship Between Cardiac Troponin in People Hospitalised for Exacerbation of COPD and Major Adverse Cardiac Events (MACE) and COPD Readmissions

Background

No single biomarker currently risk stratifies chronic obstructive pulmonary disease (COPD) patients at the time of an exacerbation, though previous studies have suggested that patients with elevated troponin at exacerbation have worse outcomes. This study evaluated the relationship between peak cardiac troponin and subsequent major adverse cardiac events (MACE) including all-cause mortality and COPD hospital readmission, among patients admitted with COPD exacerbation.

Methods

Data from five cross-regional hospitals in England were analysed using the National Institute of Health Research Health Informatics Collaborative (NIHR-HIC) acute coronary syndrome database (2008-2017). People hospitalised with a COPD exacerbation were included, and peak troponin levels were standardised relative to the 99th percentile (upper limit of normal). We used Cox Proportional Hazard models adjusting for age, sex, laboratory results and clinical risk factors, and implemented logarithmic transformation (base-10 logarithm). The primary outcome was risk of MACE within 90 days from peak troponin measurement. Secondary outcome was risk of COPD readmission within 90 days from peak troponin measurement.

Results

There were 2487 patients included. Of these, 377 (15.2%) patients had a MACE event and 203 (8.2%) were readmitted within 90 days from peak troponin measurement. A total of 1107 (44.5%) patients had an elevated troponin level. Of 1107 patients with elevated troponin at exacerbation, 256 (22.8%) had a MACE event and 101 (9.0%) a COPD readmission within 90 days from peak troponin measurement. Patients with troponin above the upper limit of normal had a higher risk of MACE (adjusted HR 2.20, 95% CI 1.75-2.77) and COPD hospital readmission (adjusted HR 1.37, 95% CI 1.02-1.83) when compared with patients without elevated troponin.

Conclusion

An elevated troponin level at the time of COPD exacerbation may be a useful tool for predicting MACE in COPD patients. The relationship between degree of troponin elevation and risk of future events is complex and requires further investigation.

Is high sensitivity troponin, taken regardless of a clinical indication, associated with 1 year mortality in critical care patients?

The aim of this study was to assess whether high sensitivity troponin (hs-cTnI) is associated with 1 year mortality in critical care (CC). One year mortality data were obtained from NHS Digital for a consecutive cohort of patients admitted to general CC unit (GCCU) and neuroscience CC unit (NCCU) who had hs-cTnI tests performed throughout their CC admission, regardless of whether the test was clinically indicated. Cox proportional hazards were used to estimate the risk of 1-year mortality. A landmark analysis was undertaken to assess whether any relationship at 1 year was driven by mortality within the first 30 days. A total of 1033 consecutive patients were included. At 1 year 254 (24.6%) patients had died. The admission log(10)hs-cTnI concentration in the entire cohort (HR 1.35 (95% CI 1.05-1.75) p = 0.009 with a bootstrap of 1000 samples) was independently associated with 1 year mortality. On landmark analysis the association with 1 year mortality was driven by 30 day mortality. These results indicate that admission hs-cTnI concentration is independently associated with 1 year mortality in CC and this relationship may be driven by differences in mortality at 30 days.