Trajectories of cardiac troponin in the decades before cardiovascular death: a longitudinal cohort study

Age-specific prognosis of acute and steady minor elevations in cardiac troponin among non-acute myocardial infarction inpatients: a large real-world cohort study

BACKGROUND

The upper reference limit of normal (ULN) of cardiac troponin (cTn) for older adults can be higher than for young adults, while the same ULN is used for both older and young adults in the current clinical practice.

METHODS

In this multicentre longitudinal cohort study, non-acute myocardial infarction (non-AMI) inpatients with at least two cTn concentrations hospitalised between 2013 and 2022 in the Tianjin Health and Medical Data Platform were included. Multivariable Cox proportional hazards and landmark regression models were used to estimate the risk of in-hospital, 30-day and 1-year mortality in different cTn groups (normal, stable minor elevation (1-2×ULN with variation ≤20%), acute minor elevation (1-2×ULN with variation >20%) and apparent elevation (>2×ULN)).

RESULTS

A total of 57 117 patients (mean age, 69.6 (13.6) years; 25 037 (43.8%) female) were included. Even minor elevation in cTn was associated with higher mortality risk. Compared with the normal cTn group, the adjusted HRs of in-hospital mortality for patients with steady minor elevation, acute minor elevation and >2× ULN in cTn were 1.70 (95% CI 1.25 to 2.33), 1.92 (95% CI 1.59 to 2.32) and 4.03 (95% CI 3.50 to 4.65), respectively. Similar trends were found for all-cause 30-day and 30-day to 1-year mortality. Among older adults, compared with the steady minor elevation group, patients with acute minor elevation in cTn had higher 30-day mortality risk (HR 1.30, 95% CI 1.02 to 1.65) but similar 30-day to 1-year mortality risk (HR 0.95, 95% CI 0.82 to 1.10), while among non-older adults, differences in short-term and 1-year mortality risks between the two groups were not statistically significant (p>0.05).

CONCLUSIONS

In non-AMI inpatients, including older adults, any stable or acute elevation in cTn, even minor, warrants attention. Further studies are needed to assess whether these patients can benefit from more aggressive treatment approaches.

Cardiac Troponin I and T Ratio and Risk of Cardiovascular or Non-Cardiovascular Events in a General Population

BACKGROUND

Emerging evidence suggests that the ratio between cardiac troponin (cTn) I and T may provide information on the risk of adverse outcomes in individuals with cardiovascular disease. Whether the cTn I/T ratio provides prognostic insights in the general population is unknown.

METHODS

The cTn I/T ratio was calculated in 8855 participants (43% female, median age 56 years) from the Generation Scotland Study where both cTnI and cTnT concentrations were above the limit of blank. Multivariable cause-specific Cox proportional hazard models were used to estimate the associations between cTn I/T ratio and the primary outcome of cardiovascular or non-cardiovascular death.

RESULTS

The median cTn I/T ratio was 0.5 (25th-75th percentile, 0.3-0.8) and median follow-up was 11.4 (10.8-12.7) years. Individuals in the highest ratio tertile (≥0.64) were more likely to be male, have a higher body mass index and systolic blood pressure, and a history of cardiovascular disease. Those in the lowest ratio tertile (<0.38) were more likely to be smokers or have diabetes. After adjustment for cardiovascular risk factors, the cTn I/T ratio was positively associated with cardiovascular death (per doubling increase, adjusted hazard ratio [HR] 1.16 [95% CI, 1.05-1.28]), while an inverse association was observed for non-cardiovascular death (HR 0.89 [95% CI, 0.81-0.99]).

CONCLUSIONS

The cTn I/T ratio is positively associated with cardiovascular death in the general population, while inversely associated with non-cardiovascular death. Future research is needed to unravel underlying mechanisms and determine whether the cTn I/T ratio provides valuable information regarding risk of cardiovascular and non-cardiovascular mortality to guide further management.

Unselected cardiac troponin testing and the diagnosis of myocardial infarction in the emergency department

BACKGROUND

This research examines the role of systematic cardiac troponin evaluation in identifying type 1 myocardial infarction among patients presenting to the emergency department with collected blood samples.

METHODS

This was a prospective study of consecutive adult patients presenting to the emergency department of a university hospital between October 22, 2020, and January 11, 2021. Cardiac troponin I levels were measured in all patients, including those with suspected acute coronary syndrome (clinical testing) and a control group undergoing routine blood tests (non-clinical testing). The primary outcomes were the prevalence of type 1 myocardial infarction and the positive predictive value of cardiac troponin I, which were assessed using established statistical methods.

RESULTS

Elevated cardiac troponin levels were identified in 13.4% of the study population (382/2,853). This included 19.5% of patients with clinically guided tests and 10.1% of those with non-clinical testing. The overall prevalence of type 1 myocardial infarction was 2%, with a positive predictive value of 14.9% (95% CI: 13.6-16.2). Among clinically guided tests, type 1 myocardial infarction prevalence was 5.8%, yielding a positive predictive value of 29.5% (95% CI: 26.7-32.4). Cases from non-clinically guided tests were primarily attributed to type 2 myocardial infarction or non-ischemic myocardial injury.

CONCLUSION

Using a generalized approach to cardiac troponin testing in emergency department patients significantly lowers the diagnostic accuracy for type 1 myocardial infarction, reducing the positive predictive value and frequently indicating non-ischemic myocardial injury.

High-sensitivity cardiac troponin I and risk of dementia: 25-year longitudinal study in the Whitehall II cohort

Objective

We hypothesise that subclinical myocardial injury during midlife, indexed by increases in cardiac troponin I, is associated with accelerated cognitive decline, smaller structural brain volume, and higher risk of dementia.

Design

Longitudinal cohort study.

Setting

Civil service departments in London (Whitehall II study).

Participants

5985 participants aged 45-69 had cardiac troponin I measured by high-sensitivity assay at baseline (1997-99) for prospective cohort analyses. A nested case-control sample of 3475 participants (695 dementia cases and 2780 matched controls) was used for backward cardiac troponin I trajectory analysis. 641 participants provided magnetic resonance imaging (MRI) scans for brain volume analysis.

Main outcome measures

Incident dementia cases were ascertained from national hospital episode statistics, mental health and mortality registers until 2023. Cognitive testing was performed at six waves over 25 years (1997-99, 2002-04, 2007-09, 2012-13, 2015-16, 2019-22). Brain volume metrics were derived from structural MRI scans (2012-16).

Results

For prospective cohort analyses, 606 (10.1%) incident cases of dementia were recorded over a median follow-up of 24.8 years. Doubling of cardiac troponin was associated with 11% higher risk of dementia (HR=1.11, 95% CI: 1.04 to 1.19). Participants with increased cardiac troponin at baseline had a faster decline of cognitive function with age. Compared to participants with concentrations below the limit of quantitation (<2.5 ng/L), those in the upper third (>5.2 ng/L) had similar global cognitive z score at age 60, but had 0.10 (95% CI: 0.02 to 0.18) standard deviations lower score at age 80, and 0.19 (0.03 to 0.35) standard deviations lower score at age 90. Participants with dementia had increased cardiac troponin concentrations compared with those without dementia between 7 and 25 years before diagnosis. Compared to those with low cardiac troponin level (<2.5 ng/L at baseline) those with concentrations >5.2 ng/L had lower grey matter volume and higher hippocampal atrophy 15 years later, equivalent to ageing effects of 2.7 and 3 years, respectively.

Conclusions

Subclinical myocardial injury at midlife was associated with higher dementia risk in later life.

Cardiovascular biomarkers: exploring troponin and BNP applications in conditions related to carbon monoxide exposure

BACKGROUND

The diagnosis and prognosis of cardiovascular disorders are greatly aided by cardiovascular biomarkers. The uses of troponin and B-type natriuretic peptide in situations involving carbon monoxide exposure are examined in this narrative review. These biomarkers are important because they help predict outcomes in cardiovascular disorders, track the effectiveness of therapy, and influence therapeutic choices.

MAIN BODY

Clinical practice makes considerable use of B-type natriuretic peptide (BNP), which has diuretic and vasodilatory effects, and troponin, a particular marker for myocardial injury. Carbon monoxide (CO) poisoning is a major worldwide health problem because CO, a "silent killer," has significant clinical consequences. Higher risk of cardiac problems, poorer clinical outcomes, and greater severity of carbon monoxide poisoning are all linked to elevated troponin and B-type natriuretic peptide levels. BNP's adaptability in diagnosing cardiac dysfunction and directing decisions for hyperbaric oxygen therapy is complemented by troponin's specificity in identifying CO-induced myocardial damage. When combined, they improve the accuracy of carbon monoxide poisoning diagnoses and offer a thorough understanding of cardiac pathophysiology.

CONCLUSIONS

To sum up, this review emphasizes the importance of troponin and B-type natriuretic peptide (BNP) as cardiac indicators during carbon monoxide exposure. While BNP predicts long-term cardiac problems, troponin is better at short-term morbidity and death prediction. When highly sensitive troponin I (hsTnI) and B-type natriuretic peptide are combined, the diagnostic accuracy of carbon monoxide poisoning patients is improved. One of the difficulties is evaluating biomarker levels since carbon monoxide poisoning symptoms are not always clear-cut. Accurate diagnosis and treatment depend on the investigation of new biomarkers and the use of standardized diagnostic criteria. The results advance the use of cardiovascular biomarkers in the intricate field of carbon monoxide exposure.