Troponins, Acute Coronary Syndrome and Renal Disease: From Acute Kidney Injury Through End-stage Kidney Disease

Use of glomerular filtration rate to estimate perioperative cardiac risk

Preoperative estimated glomerular filtration rate is an inexpensive but useful tool in predicting cardiovascular perioperative complications. Estimated glomerular filtration rate, especially considering its interaction with age, might act as a proxy for severity of cardiovascular disease. Further studies regarding the predictive power of estimated glomerular filtration rate to identify patients at risk of perioperative cardiovascular complications are essential.

Current and novel biomarkers in cardiogenic shock

Cardiogenic shock (CS) carries a 30-50% in-hospital mortality rate, with little improvement in outcomes in the last decade. Challenges in improving outcomes are closely linked to the frequent late presentation or diagnosis of CS where the 'point of no return' has often passed, leading to haemodynamic dysregulation, progressive myocardial depression, hypotension, and a downward spiral of hypoperfusion, organ dysfunction and decreasing myocardial function, driven by inflammation and metabolic derangements. Novel therapeutic interventions may have varying efficacy depending on the type and stage of shock in which they are applied. Biomarkers that aid prediction and early detection of CS, provide early signs of organ dysfunction and define prognosis could help optimize management. Temporal change in such biomarkers, particularly in response to pharmacological interventions and/or mechanical circulatory support, can guide management and predict outcome. Several novel biomarkers enhance the prediction of mortality in CS, compared to conventional parameters such as lactate, with some, such as adrenomedullin and circulating dipeptidyl peptidase 3, also able to predict the development of CS. Some biomarkers reflect systemic inflammation (e.g. interleukin-6, angiopoietin 2, fibroblast growth factor 23 and suppressor of tumorigenicity 2) and are not specific to CS, yet inform on the activation of important pathways involved in the downward shock spiral. Other biomarkers signal end-organ hypoperfusion and could guide targeted interventions, while some may serve as novel therapeutic targets. We critically review current and novel biomarkers that guide prediction, detection, and prognostication in CS. Future use of biomarkers may help improve management in these high-risk patients.

Cardiorenal Syndrome in Heart Failure with Preserved Ejection Fraction: Insights into Pathophysiology and Recent Advances

BACKGROUND

Cardiorenal syndrome (CRS) refers to the bidirectional interactions between the acutely or chronically dysfunctioning heart and kidney that lead to poor outcomes. Due to the evolving literature on renal impairment and heart failure with preserved ejection fraction (HFpEF), this review aimed to highlight the pathophysiological pathways, diagnosis using imaging and biomarkers, and management of CRS in patients with HFpEF.

SUMMARY

The mechanism of CRS in HFpEF can be hypothesized due to the interplay of elevated central venous pressure, renin-angiotensin-aldosterone system (RAAS) activation, oxidative stress, endothelial dysfunction, coronary microvascular dysfunction, and chronotropic incompetence. The correlation between HFpEF and worsening renal function seen in both long-term trials and observational data points to the evidence for these mechanisms. Upcoming biomarkers such as cystatin C, NGAL, NAG, KIM-1, ST-2, and galectin-3, along with conventional ones, are promising for early diagnosis, risk stratification, or response to therapy. Despite the lack of specific treatment for CRS in HFpEF, the management can be discussed with similar medications used in goal-directed medical therapy for heart failure with reduced ejection fraction (HFrEF). Additionally, there is increasing evidence for the role of vasodilators, inotropes, assist devices, and renal denervation, although long-term studies are necessary.

KEY MESSAGE

The management of CRS in HFpEF is an evolving field that currently shows promise for using diagnostic and prognostic biomarkers, conventional heart failure medications, and novel therapies such as renal denervation, interatrial shunt, and renal assist devices. Further studies are needed to understand the pathophysiological pathways, validate the use of novel biomarkers, especially for early diagnosis and prognostication, and institute new management strategies for CRS in patients with HFpEF.

Cardiac Troponin Levels in Patients with Chronic Kidney Disease: "Markers of High Risk or Just Noise''?

Kidney disease is linked to the development of cardiovascular disorders, further increasing morbidity and mortality in this high-risk population. Thus, early detection of myocardial damage is imperative in order to prevent devastating cardiovascular complications within this patient group. Over the years, cardiac biomarkers have been identified and are now widely used in everyday clinical practice. More specifically, available data suggest that cardiac troponin and its regulatory subunits (TnT, TnI, and TnC) reflect the injury and necrosis of myocardial tissue. While cTnC is identical in cardiac and skeletal muscle, TnT and TnI constitute cardiac-specific forms of troponin, and, as such, they have been established by international societies as biomarkers of cardiac damage and diagnostic indicators for acute myocardial infarction. Elevations in the levels of both cardiac troponins (cTnT and cTnI) have been also reported in asymptomatic patients suffering from chronic kidney disease. Therefore, if abnormal, they often generate confusion among clinicians regarding the interpretation and clinical significance of their numerical values in emergency settings. The aim of this review is to explore the reasons behind elevated troponin levels in patients with chronic kidney disease and identify when these elevated levels of biomarkers indicate the need for urgent intervention, considering the high cardiovascular risk in this patient group.

Pulmonary Embolism in Critically Ill Patients-Prevention, Diagnosis, and Management

Critically ill patients in the intensive care unit (ICU) are often immobilized and on mechanical ventilation, placing them at increased risk for thromboembolic diseases, particularly deep vein thrombosis (DVT) and, to a lesser extent, pulmonary embolism (PE). While these conditions are frequently encountered in the emergency department, managing them in the ICU presents unique challenges. Although existing guidelines are comprehensive and effective, they are primarily designed for patients presenting with PE in the emergency department and do not fully address the complexities of managing critically ill patients in the ICU. This review aims to summarize the available data on these challenging cases, offering a practical approach to the prevention, diagnosis, and treatment of PE, particularly when it is acquired in the ICU.

Acute Kidney Injury and High-Sensitivity Cardiac Troponin T Levels in the Emergency Department

Importance

The clinical implications of high-sensitivity cardiac troponin T (hs-cTnT) measurements in patients with acute kidney injury (AKI) in the emergency department (ED) are largely unknown.

Objectives

To investigate associations between serum creatinine (SCr) concentrations and hs-cTnT kinetics, as well as the clinical accuracy of hs-cTnT for myocardial infarction (MI) in patients with AKI.

Design, Setting, and Participants

This retrospective cohort study included 15 111 patient visits to 7 EDs in Sweden from December 9, 2010, to August 31, 2017, by patients 18 years or older fulfilling AKI criteria with 2 or more SCr measurements and 1 or more hs-cTnT measurement. Statistical analysis was performed from October 2, 2022, to September 28, 2023.

Exposure

Dynamic change in SCr during the ED visits.

Main Outcomes and Measures

Linear mixed-effects models were used to estimate the log-linear regression of kinetic change in hs-cTnT. Logistic regression models were applied to calculate odds ratios (ORs) for change in hs-cTnT indicating acute myocardial injury (Δhs-cTnT >20% and elevated hs-cTnT >14 ng/L) in association with change in SCr, and to assess the diagnostic performance of hs-cTnT for MI in patients with chest pain.

Results

There was a total of 15 211 visits by 13 638 patients (median age, 74 years [IQR, 64-83 years]; 8709 men [57%]), of whom 1174 (8%) had an MI. Overall, 11 353 of patients at 14 037 visits without an MI diagnosis (81%) had myocardial injury, and 4396 patients at 14 037 visits (31%) had acute myocardial injury. The change in hs-cTnT among patients without MI was 1.8-fold higher in the highest vs the lowest change in SCr quartile (64.7% [95% CI, 58.4%-71.5%] vs 36.3% [95% CI, 32.4%-40.7%]; exponentiated β coefficient, 1.78 [95% CI, 1.62-1.96]). Patients in the former group were twice as likely to have acute myocardial injury (39% [1378 of 3516 visits] vs 23% [817 of 3507 visits]; adjusted OR, 2.32 [95% CI, 2.08-2.59]). Using a 0 hours hs-cTnT cutoff value of 52 ng/L or higher assigned 627 of 2388 patients (26%) with chest pain to a high-risk group in whom the specificity and positive predictive value for MI was low (78.5% [95% CI, 76.7%-80.2&] and 27.6% [95% CI, 24.1%-31.3%], respectively).

Conclusions and Relevance

This cohort study of patients in the ED suggests that dynamic change in SCr among patients with AKI was associated with hs-cTnT concentrations indicative of acute myocardial injury. These observations were accompanied by poor performance of recommended hs-cTnT-based algorithms for MI risk stratification.

Left ventricular remodeling and its correlation with serum cardiac troponin I in patients with end-stage renal disease treated

OBJECTIVE

To investigate the effects of different blood purification modes on left ventricular remodeling and its relationship with serum cardiac troponin I (cTnI) in patients with end-stage renal disease (ESRD).

METHOD

A total of 108 patients with ESRD were selected, 55 cases were divided into hemodialysis combined with hemoperfusion (HD + HP) group, in which patients participants accepted routine hemodialysis for three times/week and hemoperfusion for three times/month; 53 cases in hemodialysis combined with hemodialysis filtration (HD + HDF) group, routine hemodialysis three times/week + hemodialysis filtration three times/month. The total duration of dialysis in the study was 1 year. Cardiac troponin I (cTnI) levels were measured before dialysis and 1 year after treatment, and related parameters were measured by echocardiography, including ventricular septal thickness (IVST), left ventricular posterior wall thickness (LVPWT), left ventricular end diastolic diameter (LVEDd), left ventricular end systolic diameter (LVEDs), and left ventricular myocardial mass index (LVMI). The paired t test was used within the group. Correlation analysis was performed using Spearman correlation analysis.

RESULT

After treatment, the levels of cTnI, IVST, LVPWT, LVEDd, LVEDs, and LVMI in the two groups were increased, and the results were statistically significant (all p < 0.05). In addition, cTnI of the two groups was significantly correlated with IVST, LVPWT, LVEDd, LVEDs, and LVMI (all p < 0.05).

CONCLUSION

Left ventricular remodeling is common in patients with ESRD, HD + Hp, and HD + HDF cannot reduce the phenomenon of left ventricular remodeling, cTnI can be used as a predictor of left ventricular hypertrophy and enlargement.

Management Considerations for Acute Coronary Syndromes in Chronic Kidney Disease

PURPOSE OF REVIEW

Propensity of patients with chronic kidney disease (CKD) to adverse outcomes of acute coronary syndromes (ACS) derives, in part, from imperfection in management. Dearth of data resulting from underrepresentation of patients with CKD in ACS trials and underuse of evidence-based testing and therapy compound biological risks inherent to CKD. We sought in this narrative review to critically appraise contemporary evidence and offer suggested approaches to practicing clinicians for the optimization of ACS management in patients with CKD.

RECENT FINDINGS

Updated multisociety chest pain guidelines emphasize the diversity of clinical presentations of ACS, pertinent to recognition of ACS in patients with CKD. Evolving tools to predict and prevent acute kidney injury complicating invasive management of ACS serve to support improved access to and safety of percutaneous coronary intervention (PCI) in CKD patients, who remain at elevated risk. Growth in use of radial access, advances in PCI quality, incorporation of intravascular imaging, and new options and insights in pharmacotherapy contribute to an evolving calculus of ischemic and bleeding risk in ACS with bearing on management in CKD patients. Key opportunities to improve outcomes of ACS for patients with CKD center on avoiding underuse of beneficial medical and invasive therapies; enhancing safety of therapies by leveraging evidence-based strategies to prevent acute kidney injury; and devoting specific effort to investigation of ACS management in the context of CKD.

Effect on QTc interval by switching from methadone to equipotent R-methadone dose in methadone maintenance treatment patients

Methadone (R,S-methadone) can prolong the QT interval. R-methadone inhibits cardiac potassium channel function less than S-methadone. We tested if switching from methadone to R-methadone would reduce corrected QT (QTc) intervals in methadone maintenance treatment (MMT) patients. Nine patients, with automatically read QTc intervals ≥450 ms, were required to detect a 20 ms (clinically relevant) reduction in QTc intervals with 15 ms standard deviation (SD) and 90% power. Nine stabilized MMT patients, using median (range) 70 (40-120) mg methadone, were included. Data (ECG recordings, serum samples, and withdrawal symptoms) were collected both before drug intake (Cmin ) and at 3 h after drug intake (Cmax ), and were collected on the day before the switch from methadone to equipotent R-methadone dose and at 14 and 28 days after the switch. A cardiologist calculated QTc intervals retrospectively. Serum electrolytes and methadone concentrations were measured. Mean QTc intervals at Cmin were 472 ms and 422 ms on methadone (automatically and manually read) and 414 ms on R-methadone (manually read). Mean (SD) change in QTc intervals was -8 (10) ms (p = 0.047) at Cmin but non-significant at Cmax . R-methadone showed a concentration-dependent relationship with QTc intervals. Switching to R-methadone reduced QTc intervals, but far less than the 20 ms considered clinically relevant.

Clinical Interpretation of Serum Troponin in the Era of High-Sensitivity Testing

Cardiac troponin (Tn) plays a central role in the evaluation of patients with angina presenting with acute coronary syndrome. The advent of high-sensitivity assays has improved the analytic sensitivity and precision of serum Tn measurement, but this advancement has come at the cost of poorer specificity. The role of clinical judgment is of heightened importance because, more so than ever, the interpretation of serum Tn elevation hinges on the careful integration of findings from electrocardiographic, echocardiographic, physical exam, interview, and other imaging and laboratory data to formulate a weighted differential diagnosis. A thorough understanding of the epidemiology, mechanisms, and prognostic implications of Tn elevations in each cardiac and non-cardiac etiology allows the clinician to better distinguish between presentations of myocardial ischemia and myocardial injury-an important discernment to make, as the treatment of acute coronary syndrome is vastly different from the workup and management of myocardial injury and should be directed at the underlying cause.

Incidence of Myocardial Injury and Cardiac Dysfunction After Adult Traumatic Brain Injury: A Systematic Review and Meta-analysis

Myocardial injury and cardiac dysfunction after traumatic brain injury (TBI) have been reported in observational studies, but there is no robust estimate of their incidences. We conducted a systematic review and meta-analysis to estimate the pooled incidence of myocardial injury and cardiac dysfunction among adult patients with TBI. A literature search was conducted using MEDLINE and EMBASE databases from inception to November 2022. Observational studies were included if they reported at least one abnormal electrocardiographic finding, elevated cardiac troponin level, or echocardiographic evaluation of systolic function or left ventricular wall motion in adult patients with TBI. Myocardial injury was defined as elevated cardiac troponin level according to the original studies and cardiac dysfunction was defined as the presence of left ventricular ejection fraction <50% or regional wall motion abnormalities assessed by echocardiography. The meta-analysis of the pooled incidence of myocardial injury and cardiac dysfunction was performed using random-effect models. The pooled estimated incidence of myocardial injury after TBI (17 studies, 3,773 participants) was 33% (95% CI: 27%-39%, I2:s 93%), and the pooled estimated incidence of cardiac dysfunction after TBI (9 studies, 557 participants) was 16.% (95% CI: 9%-25.%, I2: 84%). Although there was significant heterogeneity between studies and potential overestimation of the incidence of myocardial injury and cardiac dysfunction, our findings suggest that myocardial injury occurs in approximately one-third of adults after TBI, and cardiac dysfunction occurs in approximately one-sixth of patients with TBI.

Perioperative myocardial injury is associated with increased postoperative non-cardiac complications in patients undergoing vascular surgery: a post hoc analysis of a randomised clinical pilot trial

BACKGROUND

Elevated cardiac biomarkers, such as high-sensitivity cardiac Troponin T and N-terminal pro-B-type natriuretic peptide improve the prediction of major adverse cardiac events. However, very few trials have investigated the association between perioperative cardiac injury and non-cardiac complications. The primary aim of this study was to determine the association between peri-operative myocardial injury and non-cardiac complications in patients undergoing vascular surgery. Additionally, the association between elevated pre-operative high-sensitivity cardiac Troponin T or N-terminal pro-B-type natriuretic peptide and non-cardiac complications was explored.

METHODS

This study is a post hoc analysis of a multicentre randomised controlled trial. Patients were recruited from three centres in Sweden between 2016 and 2019. Cardiac troponin level was measured pre-operatively and at 4, 24, and 48 h after the start of surgery in patients undergoing vascular surgery. N-terminal pro-B-type natriuretic peptide was measured pre-operatively. The primary outcome was a composite of major postoperative non-cardiac complications assessed at 30 days.

RESULTS

A total of 184 patients undergoing peripheral or aortic vascular surgery were included in this study. The primary endpoint occurred in 67 (36%) patients. Perioperative myocardial injury was significantly associated with non-cardiac complications, with an adjusted odds ratio (OR) of 2.71 (95% confidence interval 1.33-5.55, P = 0.01). Sensitivity and specificity were 0.40 and 0.81, respectively. No association was found between pre-operative hs-cTnT or NT-proBNP and non-cardiac complications.

CONCLUSION

In this pilot study, we found that new peri-operative myocardial injury is associated with an increased risk of non-cardiac complications within 30 days after index surgery in patients undergoing vascular surgery. Pre-operative high-sensitivity cardiac Troponin T or N-terminal pro-B-type natriuretic peptide did not appear to predict non-cardiac complications. Larger studies are needed to confirm our findings.

TRIAL REGISTRATION

EudraCT database: 2016-001584-36.

Role of Cardiac Troponins in Predicting Adverse Outcomes in Acute Coronary Syndrome With Renal Dysfunction

A substantial global cause of mortality as well as disability is acute myocardial infarction (AMI). It is also widespread knowledge that patients with chronic kidney disease (CKD) possess greater mortality and cardiovascular disease risks than the rest of the population. A vital biomarker for the diagnosis of AMI is high-sensitive cardiac troponin T (hs-cTnT). Individuals afflicted with severe CKD frequently exhibit increased hs-cTnT levels, which can pose a significant diagnostic challenge in cases of non-ST elevation acute coronary syndrome (NSTE-ACS) necessitating revascularization. Alteration in kidney function exerts an impact on troponin levels, making a single value less useful. As the renal population has an increased risk of non-ST-segment elevation myocardial infarction (NSTEMI), serial tracking of cardiac biomarkers is essential to detect ACS in this population. Numerous studies using algorithmic remedies based on admission troponin and spontaneous variations in troponin concentration have been put forth by researchers to address these issues. A considerable majority of CKD patients can be accurately diagnosed or excluded from having AMI using the approach, which involves serial measures. Patients who suffer from kidney impairment exhibit lesser chances of undergoing angiography or revascularization and receiving preventative therapies. Furthermore, their outcomes are comparatively poorer when compared to patients who possess normal kidney function. Despite studies indicating a higher risk of poor outcomes after AMI in this population, these patients are less likely to receive guideline-indicated care. In this study, we employed a systematic literature review (SLR) methodology to provide an account of the available studies and to draw attention to the importance of cardiac troponins in predicting unfavorable outcomes and algorithms in the prediction, diagnosis, and prognosis of patients with ACS and renal impairment. Eight papers were chosen for in-depth analysis after reviewing 86 articles from trusted publications between 2013 and August 3, 2023. The analysis considered factors such as sensitivity, severity of renal damage, algorithms used, the benefits of algorithms, and the challenges. One must examine the change in cardiac troponin (cTn) and take higher cut-off values into consideration in order to increase the sensitivity and specificity for the diagnosis of AMI. Higher levels of cTn have also been correlated prognostically to unfavorable outcomes like incident heart failure and death from cardiovascular causes. Also, raised troponin levels have been linked to all-cause and cardiovascular death in both dialysis patients and patients with CKD who did not receive dialysis. Future studies should concentrate on whether troponin testing can reclassify risk and provide treatment in people with CKD who are at the greatest threat of death. The clinical practice benefits of routinely measuring cardiac troponin concentrations are largely unknown. Future research should also concentrate on figuring out how troponin testing can influence clinical management and how to address the root reasons for chronic hs-cTnT elevation in patients with CKD, which may include elements like uremic toxicity, macrovascular or microvascular ischemia, anemia, as well as reduced renal clearance.

Cardiovascular impairment in Shiga-toxin-2-induced experimental hemolytic-uremic syndrome: a pilot study

Introduction

Hemolytic-uremic syndrome (HUS) can occur as a systemic complication of infection with Shiga toxin (Stx)-producing Escherichia coli (STEC). Most well-known aspects of the pathophysiology are secondary to microthrombotic kidney disease including hemolytic anemia and thrombocytopenia. However, extrarenal manifestations, such as cardiac impairment, have also been reported. We have investigated whether these cardiac abnormalities can be reproduced in a murine animal model, in which administration of Stx, the main virulence factor of STEC, is used to induce HUS.

Methods

Mice received either one high or multiple low doses of Stx to simulate the (clinically well-known) different disease courses. Cardiac function was evaluated by echocardiography and analyses of biomarkers in the plasma (troponin I and brain natriuretic peptide).

Results

All Stx-challenged mice showed reduced cardiac output and depletion of intravascular volume indicated by a reduced end-diastolic volume and a higher hematocrit. Some mice exhibited myocardial injury (measured as increases in cTNI levels). A subset of mice challenged with either dosage regimen showed hyperkalemia with typical electrocardiographic abnormalities.

Discussion

Myocardial injury, intravascular volume depletion, reduced cardiac output, and arrhythmias as a consequence of hyperkalemia may be prognosis-relevant disease manifestations of HUS, the significance of which should be further investigated in future preclinical and clinical studies.

Rapid diagnosis of acute myocardial infarction based on reverse transcription-accelerated strand exchange amplification of miR-208a

Acute myocardial infarction (AMI) is a prevalent cardiovascular disease associated with high morbidity and mortality, posing a significant threat to human health. Therefore, early diagnosis of AMI has become a focal point of research. MiR-208 is specifically expressed in the heart and is involved in the regulation of cardiomyocyte hypertrophy, cardiac fibrosis, and other myocardial gene expressions. It is expected to be applied in the clinical detection of AMI due to its release by damaged myocardial cells within 3 hours of AMI. In this study, we developed a denatured bubble-mediated reverse transcription-accelerated strand exchange amplification (RT-ASEA) method to detect the early biomarker miR-208a of AMI. The novel approach allowed rapid amplification of miR-208a in 15 minutes, with good performance in terms of repeatability (CV < 6%), determination limit (1 × 100 pmol L-1), and linearity (R2 = 0.9690). Based on the analysis of 42 clinical samples, a strong correlation was observed between the Ct value of miR-208a detected by the RT-ASEA method and the cTnI concentration, considered the gold standard for diagnosis of AMI. The research suggested that the RT-ASEA method could be applied to distinguish between AMI and healthy groups. The area under the receiver operating characteristic curve (AUC) was 0.9976, with a sensitivity of 96% and a specificity of 100%. Optimized RT-ASEA is a reliable and efficient method for miRNA detection. Furthermore, this study provides crucial data support for the development of miR-208a as an early biomarker for AMI, which is of great significance in life and health.

Contemporary laboratory assessment of acute cardiorenal syndrome for early diagnosis: A call for action

Acute cardiorenal syndrome (CRS), categorized as CRS type 1 and 3, is defined by the interplay of acute kidney injury or dysfunction and acute cardiac disease. For optimized diagnosis and management of CRS, strategies targeting multi-organ dysfunction must be adopted. Early diagnosis of acute CRS is important to enable timely initiation of appropriate treatment to prevent serious morbidity and mortality; however, traditional biomarkers are suboptimal. Over the past 2 decades, numerous biomarkers have been investigated for a better and more rapid diagnosis of CRS. Yet, the uptake of these contemporary biomarkers has been slow, possibly owing to the use of imperfect gold-standard reference tests. We believe that there is now scope for use of contemporary laboratory test panels to improve the diagnosis of acute CRS. In this review, we briefly discuss a proposed set of biomarkers for the diagnosis of type 1 and type 3 CRS.

Urine High-Sensitive Troponin T-Novel Biomarker of Myocardial Damage in Children

Background

The use of high-sensitive cardiac troponin T (hsTnT) in urine as a marker of cardiac damage in children has not yet been reported. Elimination of cardiac troponins is dependent on renal function; persistently increased serum hsTnT concentrations were observed among individuals with impaired renal function. The aim of this study was to investigate serum and urine hsTnT levels and its correlation in infants and children younger than 24 months of age after cardiac surgery.

Methods

This study was conducted on 90 infants and children under 24 months of age who were divided into three groups. The experimental group consisted of patients with intracardiac surgery of ventricular septal defect (VSD), first control group consisted of infants with extracardiac formation of bidirectional cavopulmonary connection (BCPC), and the second control group consisted of healthy children. Troponin T values ​​were determined in serum and urine at five time points: the first sample was taken on the day before cardiac surgery (measure 0) and the other four samples were taken after the surgery; immediately after (measure 1), on the first (measure 2), third (measure 3), and fifth postoperative day (measure 5). The first morning urine was sampled for determining the troponin T in the control group of healthy infants.

Results

A positive correlation between troponin T values in serum and urine was found. Urine hsTnT measured preoperatively in children undergoing BCPC surgery was higher (median 7.3 [IQR 6.6-13.3] ng/L) compared to children undergoing VSD surgery (median 6.5 [IQR 4.4-8.9] ng/L) as well as to healthy population (median 5.5 [IQR 5.1-6.7] ng/L). After logarithmic transformation, there was no statistically significant difference in urine hsTnT concentration between the groups at any point of measurement preoperatively or postoperatively. Statistically significant negative correlation was found between serum and urine hsTnT concentrations and glomerular filtration rate estimated by creatinine clearance. Patients who underwent surgical repair of VSD had significantly higher concentrations of troponin T in serum on the first three postoperative measurements compared to those who had BCPC surgery.

Conclusions

According to the results of this study, renal function after cardiac surgery appears to have a major effect on the urinary hsTnT concentrations, and we cannot conclude that this is an appropriate marker for the assessment of postoperative myocardial damage in children. Nevertheless, more research is needed to reach a better understanding of the final elimination of cardiac troponins in children.

Implications of elevated troponin on time-to-surgery in non-ST elevation myocardial infarction (NIHR Health Informatics Collaborative: TROP-CABG study)

Implications of elevated troponin on time-to-surgery in non-ST elevation myocardial infarction(NIHR Health Informatics Collaborative:TROP-CABG study). Benedetto et al. BACKGROUND: The optimal timing of coronary artery bypass grafting (CABG) in patients with non-ST elevation myocardial infarction (NSTEMI) and the utility of pre-operative troponin levels in decision-making remains unclear. We investigated (a) the association between peak pre-operative troponin and survival post-CABG in a large cohort of NSTEMI patients and (b) the interaction between troponin and time-to-surgery. METHODS AND RESULTS: Our cohort consisted of 1746 patients (1684 NSTEMI; 62 unstable angina) (mean age 69 ± 11 years,21% female) with recorded troponins that had CABG at five United Kingdom centers between 2010 and 2017. Time-segmented Cox regression was used to investigate the interaction of peak troponin and time-to-surgery on early (within 30 days) and late (beyond 30 days) survival. Average interval from peak troponin to surgery was 9 ± 15 days, with 1466 (84.0%) patients having CABG during the same admission. Sixty patients died within 30-days and another 211 died after a mean follow-up of 4 ± 2 years (30-day survival 0.97 ± 0.004 and 5-year survival 0.83 ± 0.01). Peak troponin was a strong predictor of early survival (adjusted P = 0.002) with a significant interaction with time-to-surgery (P interaction = 0.007). For peak troponin levels <100 times the upper limit of normal, there was no improvement in early survival with longer time-to-surgery. However, in patients with higher troponins, early survival increased progressively with a longer time-to-surgery, till day 10. Peak troponin did not influence survival beyond 30 days (adjusted P = 0.64). CONCLUSIONS: Peak troponin in NSTEMI patients undergoing CABG was a significant predictor of early mortality, strongly influenced the time-to-surgery and may prove to be a clinically useful biomarker in the management of these patients.

A 15-year-old with chest pain: An unexpected etiology

A 15-year-old female with no significant past medical history presented to the emergency department with 1 day of substernal and pleuritic chest pain, chills, cough, and hematuria. She also had swelling of the face and ankles that resolved by presentation. She was found to have elevated troponin and brain natriuretic peptide during initial workup. Electrocardiogram was normal, but there were significant pleural effusions on chest x-ray. She was strep positive and had blood pressure up to 150/90, prompting admission for cardiac monitoring and cardiology consultation. Blood pressure decreased down to 125/72 without intervention. She was afebrile with unlabored breathing and normal saturations. She was clear to auscultation bilaterally, with no abdominal distension or hepatosplenomegaly, and edema was not evident on exam. There was mild erythema to the bilateral tonsillar pillars. Initial considerations included viral myocarditis, pericarditis, and atypical nephritic syndrome. Workup revealed elevated antistreptolysin antibodies, low C3 complement, negative antineutrophil cytoplasmic antibodies, and negative flu testing. Renal sonography was unremarkable. Cardiology recommended echocardiography, which confirmed pleural effusions but revealed no cardiac abnormalities. Urinalysis revealed hematuria and mild proteinuria. Diagnosis was found to be post-streptococcal glomerulonephritis complicated by fluid overload and left ventricular strain secondary to hypertensive emergency. Post-streptococcal glomerulonephritis is the most common cause of acute glomerulonephritis in children. The mechanism of disease is a proliferation and inflammation of the renal glomeruli secondary to immunologic injury, with deposition of immune complexes, neutrophils, macrophages, and C3 after complement activation. This leads to hematuria, proteinuria, and fluid overload. Edema is present in 65%–90% of patients, progressing to pulmonary involvement in severe cases. Cardiac dysfunction secondary to fluid overload is a potentially fatal outcome in the acute setting. Physicians should consider post-streptococcal glomerulonephritis for patients presenting with hypertension, cardiac/pulmonary pathology, or symptoms of acute heart failure in the context of strep infection.

The LIFT trial: study protocol for a double-blind, randomised, placebo-controlled trial of K+-binder Lokelma for maximisation of RAAS inhibition in CKD patients with heart failure

BACKGROUND

CKD is common in heart failure (HF) and associated with morbidity and mortality, yet life-prolonging medications such as renin-angiotensin-aldosterone inhibitors (RAASi) are underused due to risk of hyperkalaemia. Sodium zirconium cyclosilicate (SZC) is a potassium-binding medication that has been shown to reduce incidence of hyperkalaemia in CKD, non-CKD, and HF populations, which we propose will support maximisation of RAASi therapy.

METHODS

We propose a 1:1 randomised, double-blind, placebo-controlled trial in which participants will receive either SZC or placebo. We will up-titrate participants' RAASi therapy while monitoring their serum potassium levels and adjusting their SZC dose if necessary. Participants with CKD and HF will be recruited from CKD and HF clinics at St George's Hospital. The total study period will be 18 months; 130 participants will be enrolled for approximately two months each following screening. Our primary outcome will be the proportion of participants who achieve maximum RAASi dose while maintaining normokalaemia. Secondary outcomes include participants reaching maximum RAASi dose without severe hyperkalaemia; time from randomisation to hyperkalaemia; time from randomisation to severe hyperkalaemia; number of RAASi dose escalations per participant; final doses of RAASi therapy; changes in quality of life score, eGFR, ACR, serum sodium, troponin T; number and duration of hospital admissions; and within-participant change in serum potassium compared to baseline.

DISCUSSION

This trial will be the first to examine the use of SZC for the maximisation of RAASi dosing in patients with advanced CKD and HF. We will assess the impact of achieving target RAASi dosing on hospital admission rates and duration of stay, with the hope that optimum RAASi treatment will translate into reduced morbidity and improved QoL. If clinical benefit is demonstrated, we hope that the joint multidisciplinary CKD-HF approach will be expanded.

TRIAL REGISTRATION

EudraCT number 2020-002946-18. Registered on 08 June 2020. Online record pending.

Chronic elevation of cardiac troponin I predicts the extent of coronary disease in hemodialysis patients presenting with acute enzyme elevation

Introduction

Elevation of cardiac troponin I (cTn-I) is associated with coronary artery disease (CAD) in asymptomatic patients with end-stage renal disease (ESRD) receiving hemodialysis. We aim to investigate the diagnostic value of chronically elevated cTn-I in ESRD patients presenting with an acute rise in serum cTn-I levels.

Methods

We performed a retrospective analysis of 364 patients. Using coronary angiography, we correlated baseline elevation of cTn-I with the severity of CAD when hemodialysis patients present with acute symptomatic elevation in serum cTn-I.

Results

In hemodialysis patients presenting with a rise in serum cTn-I above baseline levels, 59% had severe CAD, and 17% had no angiographic evidence of CAD. Hemodialysis patients with severe CAD had significantly higher baseline cTn-I levels compared to patients with non-severe CAD or normal coronaries (p < 0.0001). Baseline elevation of cTn-I in the severe CAD group was correlated with the degree of CAD occlusion (r2 0.56, p < 0.0001), fitting a positive linear model. Furthermore, baseline cTn-I differentiates between patients with and without severe CAD with a test accuracy of 0.72 (95% CI, 0.69-0.75, p < 0.001). At a value of ≥0.2 ng/mL (cutoff for myocardial necrosis), the specificity of baseline cTn-I for underlying severe CAD was 0.95.

Conclusions

Elevated baseline cTn-I has good accuracy for anticipating more advanced angiographic CAD when hemodialysis patients present with a symptomatic rise in serum cTn-I above baseline levels. Baseline elevation of cTn-I can be used for cardiac disease risk management in hemodialysis patients presenting with symptoms suggestive of CAD.