Clinical implications of high-sensitivity cardiac troponin measurements in hospitalized medical patients

Type 2 MI and Myocardial Injury in the Era of High-sensitivity Troponin

Troponin has been the cornerstone of the definition of MI since its introduction to clinical practice. High-sensitivity troponin has allowed clinicians to detect degrees of myocardial damage at orders of magnitude smaller than previously and is challenging the definitions of MI, with implications for patient management and prognosis. Detection and diagnosis are no doubt enhanced by the greater sensitivity afforded by these markers, but perhaps at the expense of specificity and clarity. This review focuses on the definitions, pathophysiology, prognosis, prevention and management of type 2 MI and myocardial injury. The five types of MI were first defined in 2007 and were recently updated in 2018 in the fourth universal definition of MI. The authors explore how this pathophysiological classification is used in clinical practice, and discuss some of the unanswered questions in this era of availability of high-sensitivity troponin.

Value of Troponin in Predicting Hospital Mortality of Older Adult Patients without Suspected Acute Coronary Syndromes

OBJECTIVES

Some authors have recommended troponin measurement to stratify patient mortality risk, but it is unclear whether troponin values add to age and routine admission laboratory tests in the prediction of in-hospital mortality of older adult patients without suspected acute coronary syndrome (ACS). The aim of our study was to determine whether troponin testing adds significantly to routine admission laboratory testing in predicting in-hospital mortality in patients without a suspected ACS.

METHODS

In 2018-2019, we reviewed all acutely admitted patients aged 60 years or older to Internal Medicine wards of a regional hospital after excluding those admitted to intensive care or with chest pain. The independent variables were troponin, age, sex, and routine admission laboratory tests. The outcome measure was in-hospital mortality. We compared c-statistics and the observed 10% to 90% risk gradients using logistic regression models for age and routine laboratory testing before and after the addition of troponin.

RESULTS

The mortality risk gradient for age and admission laboratory tests was 0.2% to 29.5%. Adding troponin did not increase the gradient significantly (0.2%-34.6%, P = 0.170), and the 95% confidence intervals for the c-statistics overlapped, increasing from 0.845 (0.818-0.876) to 0.866 (0.839-0.892).

CONCLUSIONS

In older adult patients without suspected ACS, troponin testing did not improve the prediction of hospital mortality above that of a model including age and common admission blood tests. In the absence of suspected ACS, troponin testing is not needed to predict the hospital mortality of older adult patients.

High sensitivity troponins in contemporary cardiology practice: are we turning a corner?

INTRODUCTION

Troponin is considered to be the gold standard biomarker for ruling out MI. There has been a drive to improve the diagnostic speed, and as such the high sensitivity cardiac troponin (hs-cTn) assays have been introduced into clinical practice and are now part of international guidelines. Their novel value in clinical practice more generally is becoming apparent. Areas covered: In this review we will evaluate the evidence for the use of hs-cTn assays in clinical practice, the issues with the assay and how the hs-cTn can be utilized in the future as a biomarker of cardiovascular risk. Expert commentary: The use of the hs-cTn assays as a 'rule out' test for MI is compelling, as a 'rule in' there are significant issues relating the specificity of the assay for MI. The future of the assay may lie in population screening and risk modeling.

Troponin Testing in Patients Without Chest Pain or Electrocardiographic Ischemic Changes

BACKGROUND

Although often recommended by experts, it is unclear if elevated troponin measurements have clinical utility in patients without chest pain or ischemic electrocardiographic changes.

OBJECTIVES

The objective of this study was to determine clinical utility, and downstream testing in patients with elevated troponin values but without chest pain or electrocardiographic changes.

METHODS

We selected all patients aged 30-100 years hospitalized in cardiology and internal medicine departments from July 1, 2013 until July 31, 2016. We chose a subgroup of 723 consecutive subjects with elevated troponin values for chart review to determine the proportion of patients without chest pain or ischemic electrocardiographic changes, and resultant differential treatment and downstream testing. Clinical utility was defined as coronary artery interventions or treatment of life-threatening arrhythmias.

RESULTS

Troponin measurements were sent in 52.5% of all hospitalized patients (16,519/31,448), and were elevated in 29.9% (4938/16,519). Nearly two-thirds of the patients reviewed had neither chest pain nor ischemic electrocardiographic changes (63.3% [458/723]), and the elevated troponin values did not result in coronary artery interventions or treatment of life-threatening arrhythmias. The elevated troponin values were the sole reason for hospitalization in 2.0% (n = 9), for cardiac monitoring in 6.1% (n = 28), for cardiac consultations in 11.1% (n = 51), and for left heart catheterization in 0.7% (n = 3) of the patients.

CONCLUSION

Most of the elevated troponin test results were in patients without chest pain or ischemic electrocardiographic changes, had no clinical utility, and resulted in downstream testing.

Incidentally Raised Cardiac Troponin I Has a Worse Prognosis in Older Patients Compared to Those with Normal Cardiac Troponin I and Patients with Acute Coronary Syndrome: A Cohort Study

BACKGROUND

Incidentally elevated cardiac troponin I (cTnI) levels are common in acutely unwell older patients. However, little is known about how this impacts on the prognosis of these patients.

OBJECTIVE

We aimed to investigate whether incidentally elevated cTnI levels (group 1) are associated with poorer outcome when compared to age- and sex-matched patients without an elevated cTnI level (group 2), and to patients diagnosed with acute coronary syndrome (group 3).

PATIENTS AND METHODS

This prospective, matched cohort study placed patients ≥75 years old who were admitted to a University teaching hospital into groups 1-3, based on the cTnI levels and underlying diagnosis. Outcomes were compared between the groups using mixed-effects regression models and adjusted for renal function and C-reactive protein. All-cause mortality at discharge, at 1 month and 3 months, alongside the length of hospital stay (LOS), were recorded.

RESULTS

In total, 315 patients were included, with 105 patients in each of the 3 groups. The mean age was 84.8 ± 5.5 years, with 41.9% males. All patients were followed up for 3 months. The percent all-cause mortality at discharge and the LOS for groups 1, 2 and 3 were 12.4, 3.8 and 8.6% and 11.2, 8.5 and 7.7 days, respectively. Group 1 had significantly increased mortality at 3 months [odds ratio (OR) 2.80, 95% confidence interval (CI) 1.12-6.96; p = 0.040] and LOS (OR 1.39, 95% CI 1.08-1.79; p = 0.008) compared to group 2 and did not differ significantly when compared to 3-month mortality (OR 2.39, 95% CI 0.91-6.29; p = 0.079) or LOS (OR 1.26, 95% CI 0.96-1.66; p = 0.097) in group 3.

CONCLUSION

There is a significant association between an incidental rise in cTnI level with mortality and LOS in older patients. Further research is required to evaluate whether a more systematic management of these patients would improve the prognosis.