Factors associated with baseline and serial changes in circulating NT-proBNP and high-sensitivity cardiac troponin T in a population-based cohort (Dallas Heart Study)

Optimizing the Clinical Use of High-Sensitivity Troponin Assays: A Review

Ischemic heart diseases (IHDs) remain a global health concern. Many IHD cases go undiagnosed due to challenges in the initial diagnostic process, particularly in cases of acute myocardial infarction (AMI). High-sensitivity cardiac troponin (hs-cTn) assays have revolutionized myocardial injury assessment, but variations in diagnostic cut-off values and population differences have raised challenges. This review addresses essential laboratory and clinical considerations for hs-cTn assays. Laboratory guidelines discuss the importance of establishing standardized 99th-percentile upper reference limits (URLs) considering factors such as age, sex, health status, and analytical precision. The reference population should exclude individuals with comorbidities like diabetes and renal disease, and rigorous selection is crucial. Some clinical guidelines emphasize the significance of sex-specific URL limits while others do not. They highlight the use of serial troponin assays for AMI diagnosis. In addition, timely reporting of accurate hs-cTn results is essential for effective clinical use. This review aims to provide a clearer understanding among laboratory professionals and clinicians on how to optimize the use of hs-cTn assays in clinical settings in order to ensure accurate AMI diagnosis and thus improve patient care and outcomes.

Cardiac Magnetic Resonance Left Ventricular Filling Pressure Is Associated with NT-proBNP in Patients with New Onset Heart Failure

Background and Objectives: Cardiovascular magnetic resonance (CMR) is emerging as an important imaging tool for sub-phenotyping and estimating left ventricular (LV) filling pressure (LVFP). The N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) is released from cardiac myocytes in response to mechanical load and wall stress. This study sought to investigate if CMR-derived LVFP is associated with the serum levels of NT-proBNP and, in addition, if it provides any incremental prognostic value in heart failure (HF). Materials and Methods: This study recruited 380 patients diagnosed with HF who underwent same-day CMR and clinical assessment between February 2018 and January 2020. CMR-derived LVFP was calculated, as previously, from long- and short-axis cines. During CMR assessment, serum NT-proBNP was measured. The pathological cut-offs were defined as follows: NT-proBNP ≥ 125 pg/mL and CMR LVFP > 15 mmHg. The incidence of HF hospitalisation was treated as a clinical outcome. Results: In total, 305 patients had NT-proBNP ≥ 125 pg/mL. Patients with raised NT-proBNP were older (54 ± 14 vs. 64 ± 11 years, p < 0.0001). Patients with raised NT-proBNP had higher LV volumes and mass. In addition, CMR LVFP was higher in patients with raised NT-proBNP (13.2 ± 2.6 vs. 15.4 ± 3.2 mmHg, p < 0.0001). The serum levels of NT-proBNP were associated with CMR-derived LVFP (R = 0.42, p < 0.0001). In logistic regression analysis, this association between NT-proBNP and CMR LVFP was independent of all other CMR variables, including LV ejection fraction, LV mass, and left atrial volume (coefficient = 2.02, p = 0.002). CMR LVFP demonstrated an independent association with the incidence of HF hospitalisation above NT-proBNP (hazard ratio 2.7, 95% confidence interval 1.2 to 6, p = 0.01). Conclusions: A CMR-modelled LVFP is independently associated with serum NT-proBNP levels. Importantly, it provides an incremental prognostic value over and above serum NT-proBNP levels.

Effect of Intensive Blood Pressure Control on Troponin and Natriuretic Peptide Levels: Findings From SPRINT

BACKGROUND

Given the important role of cardiac injury and neurohormonal activation in the pathways leading from hypertension to heart failure and strong associations observed between hypertension and its sequelae on hs-cTnT (high-sensitivity cardiac troponin T) and NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels, we hypothesized that intensive systolic blood pressure (SBP) lowering would decrease levels of hs-cTnT and NT-proBNP.

METHODS

hs-cTnT and NT-proBNP were measured at baseline and 1 year from stored specimens in SPRINT (Systolic Blood Pressure Intervention Trial). Changes in biomarkers were evaluated continuously on the log scale and according to categories (≥50% increase, ≥50% decrease, or <50% change). The effect of intensive SBP lowering on continuous and categorical changes in biomarker levels were assessed using linear and multinomial logistic regression models, respectively. The association between changes in biomarkers on heart failure and death was assessed using multivariable-adjusted Cox proportional hazards models.

RESULTS

Randomization to intensive SBP lowering (versus standard SBP management) resulted in a 3% increase in hs-cTnT levels over 1-year follow-up (geometric mean ratio, 1.03 [95% CI, 1.01-1.04]) and a higher proportion of participants with ≥50% increase (odds ratio, 1.47 [95% CI, 1.13, 1.90]). In contrast, randomization to intensive SBP lowering led to a 10% decrease in NT-proBNP (geometric mean ratio, 0.90 [95% CI, 0.87-0.93]) and a lower probability of ≥50% increase in NT-proBNP (odds ratio, 0.57 [95% CI, 0.46-0.72]). The association of randomized treatment assignment on change in hs-cTnT was completely attenuated after accounting for changes in estimated glomerular filtration rate over follow-up, whereas the association of treatment with NT-proBNP was completely attenuated after adjusting for change in SBP. Increases in hs-cTnT and NT-proBNP from baseline to 1 year were associated with higher risk for heart failure and death, with no significant interactions by treatment assignment.

CONCLUSIONS

Intensive SBP lowering increased hs-cTnT, mediated by the effect of SBP lowering on reduced kidney filtration. In contrast, intensive SBP lowering decreased NT-proBNP, a finding that was explained by the decrease in SBP. These findings highlight the importance of noncardiac factors influencing variation in cardiac biomarkers and raise questions about the potential role of hs-cTnT as a surrogate marker for heart failure or death in SBP-lowering studies.

High sensitivity troponins: A potential biomarkers of cardiovascular risk for primary prevention

There have been several approaches to building charts for CV risk, all of which have both strengths and limitations. Identifying early organ damage provides relevant information and should be included in risk charts, although the direct relationship with risk is imprecise, variability between operators at the time to assess, and low availability in some healthcare systems, limits its use. Biomarkers, like troponin (cTns) isoforms cTnI and cTnT, a cardiac specific myocyte injury marker, have the great advantage of being relatively reproducible, more readily accessible, and applicable to different populations. New and improved troponin assays have good analytical performance, can measure very low levels of circulating troponin, and have low intra individual variation, below 10 %. Several studies have analyzed the blood levels in healthy subjects and their predictive value for cardiovascular events in observational, prospective and post-hoc studies. All of them offered relevant information and shown that high sensitivity hs-cTnI has a place as an additional clinical marker to add to current charts, and it also reflects sex- and age-dependent differences. Although few more questions need to be answered before recommend cTnI for assessing CV risk in primary prevention, seems to be a potential strong marker to complement CV risk charts.

Do the Current Guidelines for Heart Failure Diagnosis and Treatment Fit with Clinical Complexity?

Heart failure (HF) is a clinical syndrome defined by specific symptoms and signs due to structural and/or functional heart abnormalities, which lead to inadequate cardiac output and/or increased intraventricular filling pressure. Importantly, HF becomes progressively a multisystemic disease. However, in August 2021, the European Society of Cardiology published the new Guidelines for the diagnosis and treatment of acute and chronic HF, according to which the left ventricular ejection fraction (LVEF) continues to represent the pivotal parameter for HF patients’ evaluation, risk stratification and therapeutic management despite its limitations are well known. Indeed, HF has a complex pathophysiology because it first involves the heart, progressively becoming a multisystemic disease, leading to multiorgan failure and death. In these terms, HF is comparable to cancer. As for cancer, surviving, morbidity and hospitalisation are related not only to the primary neoplastic mass but mainly to the metastatic involvement. In HF, multiorgan involvement has a great impact on prognosis, and multiorgan protective therapies are equally important as conventional cardioprotective therapies. In the light of these considerations, a revision of the HF concept is needed, starting from its definition up to its therapy, to overcome the old and simplistic HF perspective.