Interpreting Cardiac Biomarkers in the Setting of Chronic Kidney Disease

Delta troponin does not distinguish acute coronary syndrome in emergency department patients with renal impairment and an initial positive troponin

Background

In emergency department (ED) patients with renal impairment, troponin concentrations can be positive without myocardial ischemia. When there is clinical concern for acute coronary syndrome (ACS), guidelines recommend obtaining a delta troponin measurement to identify acute myocardial injury. However, evidence supporting the use of delta troponin to rule in or out ACS in patients with renal impairment and initial elevated troponin levels is limited.

Methods

This retrospective, observational study assessed the diagnostic value of a 20% delta troponin cutoff in the prediction of ACS events in ED patients (estimated glomerular filtration rate [eGFR] <60 mL/min/1.72 m2) with renal impairment, clinical concern for ACS, and an initial positive troponin concentration using either conventional troponin (cTnT) or high-sensitivity troponin (hsTnT). Clinical concern for ACS was based on initial ED physician-reported diagnoses. Patients with an initial diagnosis of ST-elevation myocardial infarction were not included. A positive initial troponin was identified at a threshold of ≥0.06 ng/mL for cTnT and ≥52 ng/L for hsTnT, and delta troponin measurements were obtained within 24 h of the initial troponin. The primary composite outcome, termed ACS event, included (1) cardiac-related mortality, (2) coronary revascularization (or its recommendation), or a (3) clinically diagnosed type-1 myocardial infarction within 6 weeks of the ED presentation. Sensitivities, specificities, negative predictive values, positive predictive values, and negative and positive likelihood ratios were calculated for these 6-week ACS events.

Results

A total of 608 ED patients with renal impairment, an initial positive troponin, and clinical concern for ACS were included in the study. Of these patients, 234 had an initial positive cTnT (median eGFR 18 mL/min/1.72 m2) and 374 had an initial positive hsTnT (median eGFR 25 mL/min/1.72 m2). The overall ACS event rate was 38% in the cTnT group and 33% in the hsTnT group. In those with a negative delta, the 6-week ACS event rate was 32% when using cTnT, compared to 24% using hsTnT. Conversely, a positive delta was associated with an ACS event rate of 47% when cTnT was utilized versus 61% when hsTnT was utilized.

Conclusion

In this study, approximately one-third of ED patients with renal impairment who had an initial positive troponin and clinical concern for ACS developed ACS events at 6 weeks. A delta troponin did not appear to provide clinically meaningful assistance in the prediction or exclusion of 6-week ACS events in this cohort.

The mechanisms underlying acute myocardial infarction in chronic kidney disease patients undergoing hemodialysis

Cardiovascular disease (CVD) is a leading cause of death in chronic kidney disease (CKD). Hemodialysis is one of the main treatments for patients with end-stage kidney disease. Epidemiological data has shown that acute myocardial infarction (AMI) accounts for the main reason for death in patients with CKD under hemodialysis therapy. Immune dysfunction and changes in metabolism (including a high level of inflammatory cytokines, a disorder of lipid and mineral ion homeostasis, accumulation of uremic toxins et al.) during CKD can deteriorate stability of atherosclerotic plaque and promote vascular calcification, which are exactly the pathophysiological mechanisms underlying the occurrence of AMI. Meanwhile, the hemodialysis itself also has adverse effects on lipoprotein, the immune system and hemodynamics, which contribute to the high incidence of AMI in these patients. This review aims to summarize the mechanisms and further promising methods of prevention and treatment of AMI in CKD patients undergoing hemodialysis, which can provide an excellent paradigm for exploring the crosstalk between the kidney and cardiovascular system.

High-Sensitivity Cardiac Troponin T to Exclude Cardiac Involvement in TTR Variant Carriers and ATTRv Amyloidosis Patients

(1) Background: Individuals carrying a pathogenic transthyretin gene variant (TTRv) are at high risk for developing hereditary transthyretin (ATTRv) amyloidosis and are routinely screened for the development of cardiomyopathy (ATTRv-CM). This study aims to evaluate whether the cardiac biomarkers N-terminal pro B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) can be used to rule out ATTRv-CM. (2) Methods: In this retrospective case-control study, data from 46 ATTRv-CM patients and 101 TTRv carriers and ATTRv amyloidosis patients without cardiomyopathy were included. Binary logistic regression models were used to assess the ability of NT-proBNP and hs-cTnT to predict the diagnosis of ATTRv-CM. An optimal cutoff for the relevant biomarker(s) was determined based on a sensitivity of ≥99% and the highest possible percentage of additional tests avoided (%ATA) in the index dataset. (3) Results: Hs-cTnT demonstrated the highest predictive capabilities for ATTRv-CM. The addition of NT-proBNP did not improve the predictive model. A hs-cTnT cutoff of <6 ng/L resulted in a 97% sensitivity and a negative predictive value of 95% with a %ATA of 30% in the validation dataset. (4) Conclusion: In conclusion, hs-cTnT is a useful biomarker for excluding cardiac involvement in TTRv carriers and ATTRv amyloidosis patients and it has the potential to prevent unnecessary diagnostic procedures.

Postoperative cardiac biomarker release is not associated with myocardial mass in computer tomography scans

OBJECTIVES

Myocardial hypertrophy results in increased levels of cardiac biomarkers in healthy individuals and in patients suffering from acute myocardial infarction. The influence of cardiac mass on postoperative cardiac biomarkers release remains unclear. This study investigated the correlation between myocardial mass and the release of high-sensitivity cardiac Troponin T (hs-cTnT) and creatine kinase-myocardial band (CK-MB) after isolated aortic valve replacement (AVR) or bypass surgery.

METHODS

Myocardial mass of a consecutive retrospective series of patients was measured automatically using preoperative computer tomography scans (636 patients, AVR = 251; bypass surgery = 385). Levels of cardiac biomarkers were measured before and serially after surgery. Spearman and Pearson correlation and a multivariate regression model was performed to measure the degree of association between myocardial mass and the release of hs-cTnT and CK-MB.

RESULTS

Patients were divided into 3 tertiles according to their myocardial mass index. Higher biomarker levels were measured preoperatively in the upper tertile of patients undergoing AVR (P = 0.004) or bypass surgery (P < 0.001). Patients with different heart sizes showed no differences in postoperative biomarker release neither after AVR nor bypass surgery. No statistical significant correlation was observed between myocardial mass index and postoperative release of hs-cTnT or CK-MB in any subgroup (ρ maximum 0.106).

CONCLUSIONS

Postoperative biomarker release is not correlated with myocardial mass. Patient factors leading to increased postoperative biomarker levels need to be elucidated in future studies.

Chronic Kidney Disease Associated with Ischemic Heart Disease: To What Extent Do Biomarkers Help?

Chronic kidney disease represents a complex and multifaceted pathology characterized by the presence of structural or functional renal anomalies associated with a persistent reduction in renal function. As the disease progresses, complications arise due to the chronic inflammatory syndrome, hydro-electrolytic disorders, and toxicity secondary to the uremic environment. Cardiovascular complications are the leading cause of death for these patients. Ischemic cardiac pathology can be both a consequence and complication of chronic kidney disease, highlighting the need to identify specific cardiorenal dysfunction biomarkers targeting pathophysiological mechanisms common to both conditions. This identification is crucial for establishing accurate diagnoses, prognoses, and risk stratifications for patients. This work is intended to elucidate the intricate relationship between chronic kidney disease and ischemic heart disease and to investigate the roles of cardiorenal biomarkers, including cardiac troponin, natriuretic peptides, galectin-3, copeptin, fibroblast growth factor 23 and its co-receptor Klotho, soluble suppression of tumorigenicity 2, and plasma growth differentiation factor 15.

A risk model for the early diagnosis of acute myocardial infarction in patients with chronic kidney disease

Introduction

Acute myocardial infarction (AMI) remains a critical disease, characterized by a high fatality rate in several countries. In clinical practice, the incidence of AMI is increased in patients with chronic kidney disease (CKD). However, the early diagnosis of AMI in the above group of patients is still poor.

Methods

In the present study, a total of 829 patients with CKD, defined by an estimated glomerular filtration rate (eGFR) of <60 ml/min/1.73 m2 or 60-90 ml/min/1.73 m2 for patients with mildly reduced kidney function, who attended the Sichuan Provincial People's Hospital (SPPH) between January 2018 and November 2022 were enrolled. All patients underwent coronary angiography due to the presence of typical or atypical symptoms of AMI. Patients were divided into the following two groups: The training cohort, including 255 participants with AMI and 242 without AMI; and the testing cohort, including 165 and 167 subjects with and without AMI, respectively. Furthermore, a forward stepwise regression model and a multivariable logistic regression model, named SPPH-AMI-model, were constructed to select significant predictors and assist the diagnosis of AMI in patients with CKD, respectively.

Results

The following factors were evaluated in the model: Smoking status, high sensitivity cardiac troponin I, serum creatinine and uric acid levels, history of percutaneous coronary intervention and electrocardiogram. Additionally, the area under the curve (AUC) of the receiver operating characteristic curve were determined in the risk model in the training set [AUC, 0.78; 95% confidence interval (CI), 0.74-0.82] vs. the testing set (AUC, 0.74; 95% CI, 0.69-0.79) vs. the combined set (AUC, 0.76; 95% CI, 0.73-0.80). Finally, the sensitivity and specificity rates were 71.12 and 71.21%, respectively, the percentage of cases correctly classified was 71.14%, while positive and negative predictive values of 71.63 and 70.70%, respectively, were also recorded.

Discussion

The results of the current study suggested that the SPPH-AMI-model could be currently considered as the only risk scoring system for the early diagnosis of AMI in patients with CKD. This method could help clinicians and emergency physicians to quickly and accurately diagnose AMI in patients with CKD to promote the immediate and effective treatment of these patients.

Associations of N-terminal pro-B-type natriuretic peptide, estimated glomerular filtration rate, and mortality in US adults

BACKGROUND

NT-proBNP is an important predictor of mortality but is inversely related to estimated glomerular filtration rate (eGFR). Whether the prognostic value of NT-proBNP is similar at different levels of kidney function is unknown.

AIMS

We evaluated the association of NT-proBNP with eGFR and its implications for all-cause and cardiovascular mortality risk in the general population.

METHODS

We included adults without prior cardiovascular disease from the National Health and Nutrition Examination Survey (NHANES) 1999 to 2004. We used linear regression to characterize the cross-sectional associations of NT-proBNP with eGFR. We used Cox regression to assess the prospective associations of NT-proBNP with mortality across categories of eGFR.

RESULTS

Among 11,456 participants (mean age 43 years, 48% female, 71% White, 11% Black), there was an inverse association between NT-proBNP and eGFR, which was stronger in those with more impaired kidney function. Per 15-unit decrease in eGFR, NT-proBNP was 4.3-fold higher for eGFR<30; 1.7-fold higher for eGFR 30 to 60, 1.4-fold higher for eGFR 61 to 90, 1.1-fold higher for eGFR 91 to 120 mL/min/1.73 m2. Over a median 17.6 years of follow-up, 2,275 deaths (622 cardiovascular) occurred. Higher NT-proBNP was associated with higher all-cause (HR per doubling of NT-proBNP: 1.20, 95% CI: 1.16-1.25) and cardiovascular mortality (HR: 1.34, 95% CI 1.25-1.44). Associations were similar across eGFR categories (P-interaction >.10). Adults with NT-proBNP≥450 pg/mL and eGFR<60 mL/min/1.73m2 had 3.4-fold higher all-cause mortality and 5.5-fold higher cardiovascular mortality risk, compared to those with NT-proBNP<125 pg/mL and eGFR>90 mL/min/1.73m2.

CONCLUSION

Despite its strong inverse association with eGFR, NT-proBNP has robust associations with mortality across the full range of kidney function in the general US adult population.

Safety and effectiveness of the short (0-1h) high sensitive troponin protocol in real-life practice

AIM

Recent guidelines recommend the use of a short 0-1h high sensitive cardiac troponin (hs-cTn) algorithm in patients presenting with chest pain at the emergency department (ED). This retrospective observational study evaluates the safety and effectiveness of the new 0-1h hs-cTn I protocol in comparison with the standard 0-3h cTn I protocol for the diagnosis of acute myocardial infarction (AMI).

METHODS

A total of two times 100 consecutive chest pain patients presenting at the ED in November/December 2018 (standard 0-3h cTn I group) and in November/December 2020 (short 0-1h hs-cTn I group) were enrolled. Decision making was based upon validated assay-specific cut-off values.

RESULTS

The new 0-1h hs-cTn I protocol had a sensitivity of 100% (95% CI 83.2-100) and a negative predictive value of 100% to rule out AMI. The accuracy of rule-in was slightly lower with a specificity of 92.5% (95% CI 84.4-97.2). The overall protocol accuracy was 94% (95% CI 87.4-97.8) in the short 0-1h hs-cTn I group compared to 88% (95% CI 80.0-93.6) in the standard 0-3h cTn I group (p-value 0.14). The 0-1h hs-cTn I protocol was associated with a numerically higher rate of early hospital discharge compared to the conventional 0-3h cTn I protocol (47% versus 59%; p-value 0.09) and with a shorter median length of stay for those patients (mean 316 min versus 289 min; p-value 0.09).

CONCLUSION

The abbreviated protocol based on the 0-1h hs-cTn I assays is effective and safe for the exclusion of AMI at the ED.

Using logistic regression models to investigate the effects of high-sensitivity cardiac troponin T confounders on ruling in acute myocardial infarction

OBJECTIVES

Confounding factors, including sex, age, and renal dysfunction, affect high-sensitivity cardiac troponin T (hs-cTnT) concentrations and the acute myocardial infarction (AMI) diagnosis. This study assessed the effects of these confounders through logistic regression models and evaluated the diagnostic performance of an optimized, integrated prediction model.

METHODS

This retrospective study included a primary derivation cohort of 18,022 emergency department (ED) patients at a US medical center and a validation cohort of 890 ED patients at a Canadian medical center. Hs-cTnT was measured with 0/3 h sampling. The primary outcome was index AMI diagnosis. Logistic regression models were optimized to predict AMI using delta hs-cTnT and its confounders as covariates. The diagnostic performance of model cutoffs was compared to that of the hs-cTnT delta thresholds. Serial logistic regressions were carried out to evaluate the relationship between covariates.

RESULTS

The area under the curve of the best-fitted model was 0.95. The model achieved a 90.0% diagnostic accuracy in the validation cohort. The optimal model cutoff yielded comparable performance (90.5% accuracy) to the optimal sex-specific delta thresholds (90.3% accuracy), with 95.8% agreement between the two diagnostic methods. Serial logistic regressions revealed that delta hs-cTnT played a more predominant role in AMI prediction than its confounders, among which sex is more predictive of AMI (total effect coefficient 1.04) than age (total effect coefficient 0.05) and eGFR (total effect coefficient -0.008).

CONCLUSIONS

The integrated prediction model incorporating confounding factors does not outperform hs-cTnT delta thresholds. Sex-specific hs-cTnT delta thresholds remain to provide the highest diagnostic accuracy.

Differences between high-sensitivity cardiac troponin T and I in stable populations: underlying causes and clinical implications

OBJECTIVES

Measurement of high-sensitivity (hs) cardiac troponin (cTn) T and I is widely studied for cardiac assessment of stable populations. Recent data suggest clinical and prognostic discrepancies between both hs-cTn. We aimed at reviewing published studies with respect to underlying causes and clinical implications.

CONTENT

We summarized current evidence on release and clearance mechanisms of cTnT and I, and on preanalytical and assay-related issues potentially portending to differences in measured concentrations. We also performed a systematic review of outcome studies comparing both hs-cTn in the general population, patients with congestive heart failure, stable coronary artery disease and atrial fibrillation.

SUMMARY AND OUTLOOK

For the interpretation of concentrations of hs-cTnT, stronger association with renal dysfunction compared to hs-cTnI should be considered. Hs-cTnT also appears to be a stronger indicator of general cardiovascular morbidity and all-cause mortality. Hs-cTnI concentrations tend to be more sensitive to coronary artery disease and ischemic outcomes. These findings apparently reflect variations in the mechanisms of cardiac affections resulting in cTn release. Whether these differences are of clinically relevance remains to be elucidated. However, having the option of choosing between either hs-cTn might represent an option for framing individualized cardiac assessment in the future.

Inflammatory pathways in heart failure with preserved left ventricular ejection fraction: implications for future interventions

Many patients with symptoms and signs of heart failure have a left ventricular ejection fraction ≥50%, termed heart failure with preserved ejection fraction (HFpEF). HFpEF is a heterogeneous syndrome mainly affecting older people who have many other cardiac and non-cardiac conditions that often cast doubt on the origin of symptoms, such as breathlessness, or signs, such as peripheral oedema, rendering them neither sensitive nor specific to the diagnosis of HFpEF. Currently, management of HFpEF is mainly directed at controlling symptoms and treating comorbid conditions such as hypertension, atrial fibrillation, anaemia, and coronary artery disease. HFpEF is also characterized by a persistent increase in inflammatory biomarkers. Inflammation may be a key driver of the development and progression of HFpEF and many of its associated comorbidities. Detailed characterization of specific inflammatory pathways may provide insights into the pathophysiology of HFpEF and guide its future management. There is growing interest in novel therapies specifically designed to target deregulated inflammation in many therapeutic areas, including cardiovascular disease. However, large-scale clinical trials investigating the effectiveness of anti-inflammatory treatments in HFpEF are still lacking. In this manuscript, we review the role of inflammation in HFpEF and the possible implications for future trials.

Preoperative cardiac troponin I as a predictor of postoperative cardiac events in patients with end stage renal disease undergoing non-cardiac surgery

We investigated if elevated cardiac troponin I (cTnI) serum levels before non-cardiac surgery were predictors of postoperative cardiac events in patients with end stage renal disease (ESRD) undergoing dialysis. In total, 703 consecutive patients with ESRD undergoing dialysis who underwent non-cardiac surgery were enrolled. Preoperative cTnI serum levels were measured at least once in all patients. The primary endpoint was defined as a composite of cardiac death, myocardial infarction (MI), and pulmonary edema during hospitalization or within 30 days after surgery in patients with a hospitalization longer than 30 days after surgery. Postoperative cardiac events occurred in 48 (6.8%) out of 703 patients (cardiac death 1, MI 18, and pulmonary edema 33). Diabetes mellitus (DM), previous ischemic heart disease, and congestive heart failure were more common in patients with postoperative cardiac events. Peak cTnI serum levels were higher in patients with postoperative cardiac event (180 ± 420 ng/L vs. 80 ± 190 ng/L, p = 0.008), and also elevated peak cTnI levels > 45 ng/L were more common in patients with postoperative cardiac events (66.8% vs. 30.5%, p < 0.001). Multivariate logistic regression analysis showed that DM (odds ratio [OR]  2.509, 95% confidence interval [CI] 1.178-5.345, p = 0.017) and serum peak cTnI levels ≥ 45 ng/L (OR 3.167, 95% CI 1.557-6.444, p = 0.001) were independent predictors for the primary outcome of cardiac death/MI/pulmonary edema. Moreover, cTnI levels ≥ 45 ng/L had an incremental prognostic value to the revised cardiac risk index (RCRI) (Chi-square = 23, p < 0.001), and to the combined RCRI and left ventricular ejection fraction (Chi-square = 12, p = 0.001). Elevated preoperative cTnI levels are predictors of postoperative cardiac events including cardiac death, MI, and pulmonary edema in patients with ESRD undergoing non-cardiac surgery.

Association of Time to Surgery After COVID-19 Infection With Risk of Postoperative Cardiovascular Morbidity

IMPORTANCE

The time interval between COVID-19 infection and surgery is a potentially modifiable but understudied risk factor for postoperative complications.

OBJECTIVE

To examine the association between time to surgery after COVID-19 diagnosis and the risk of a composite of major postoperative cardiovascular morbidity events within 30 days of surgery.

DESIGN, SETTING, AND PARTICIPANTS

This single-center, retrospective cohort study was conducted among 3997 adult patients (aged ≥18 years) with a previous diagnosis of COVID-19, as documented by a positive polymerase chain reaction test result, who were undergoing surgery from January 1, 2020, to December 6, 2021. Data were obtained through Structured Query Language access of an existing perioperative data warehouse. Statistical analysis was performed March 29, 2022.

EXPOSURE

The time interval between COVID-19 diagnosis and surgery.

MAIN OUTCOMES AND MEASURES

The primary outcome was the composite occurrence of major cardiovascular comorbidity, defined as deep vein thrombosis, pulmonary embolism, cerebrovascular accident, myocardial injury, acute kidney injury, and death within 30 days after surgery, using multivariable logistic regression.

RESULTS

A total of 3997 patients (2223 [55.6%]; median age, 51.3 years [IQR, 35.1-64.4 years]; 667 [16.7%] African American or Black; 2990 [74.8%] White; and 340 [8.5%] other race) were included in the study. The median time from COVID-19 diagnosis to surgery was 98 days (IQR, 30-225 days). Major postoperative adverse cardiovascular events were identified in 485 patients (12.1%). Increased time from COVID-19 diagnosis to surgery was associated with a decreased rate of the composite outcome (adjusted odds ratio, 0.99 [per 10 days]; 95% CI, 0.98-1.00; P = .006). This trend persisted for the 1552 patients who had received at least 1 dose of COVID-19 vaccine (adjusted odds ratio, 0.98 [per 10 days]; 95% CI, 0.97-1.00; P = .04).

CONCLUSIONS AND RELEVANCE

This study suggests that increased time from COVID-19 diagnosis to surgery was associated with a decreased odds of experiencing major postoperative cardiovascular morbidity. This information should be used to better inform risk-benefit discussions concerning optimal surgical timing and perioperative outcomes for patients with a history of COVID-19 infection.

Left ventricular dysfunction with preserved ejection fraction: the most common left ventricular disorder in chronic kidney disease patients

Chronic kidney disease (CKD) is a risk factor for premature cardiovascular disease. As kidney function declines, the presence of left ventricular abnormalities increases such that by the time kidney replacement therapy is required with dialysis or kidney transplantation, more than two-thirds of patients have left ventricular hypertrophy. Historically, much research in nephrology has focussed on the structural and functional aspects of cardiac disease in CKD, particularly using echocardiography to describe these abnormalities. There is a need to translate knowledge around these imaging findings to clinical outcomes such as unplanned hospital admission with heart failure and premature cardiovascular death. Left ventricular hypertrophy and cardiac fibrosis, which are common in CKD, predispose to the clinical syndrome of heart failure with preserved left ventricular ejection fraction (HFpEF). There is a bidirectional relationship between CKD and HFpEF, whereby CKD is a risk factor for HFpEF and CKD impacts outcomes for patients with HFpEF. There have been major improvements in outcomes for patients with heart failure and reduced left ventricular ejection fraction as a result of several large randomized controlled trials. Finding therapy for HFpEF has been more elusive, although recent data suggest that sodium-glucose cotransporter 2 inhibition offers a novel evidence-based class of therapy that improves outcomes in HFpEF. These observations have emerged as this class of drugs has also become the standard of care for many patients with proteinuric CKD, suggesting that there is now hope for addressing the combination of HFpEF and CKD in parallel. In this review we summarize the epidemiology, pathophysiology, diagnostic strategies and treatment of HFpEF with a focus on patients with CKD.

A review of cardiac troponin I detection by surface enhanced Raman spectroscopy: Under the spotlight of point-of-care testing

Cardiac troponin I (cTnI) is a biomarker widely related to acute myocardial infarction (AMI), one of the leading causes of death around the world. Point-of-care testing (POCT) of cTnI not only demands a short turnaround time for its detection but the highest accuracy levels to set expeditious and adequate clinical decisions. The analytical technique Surface-enhanced Raman spectroscopy (SERS) possesses several properties that tailor to the POCT format, such as its flexibility to couple with rapid assay platforms like microfluidics and paper-based immunoassays. Here, we analyze the strategies used for the detection of cTnI by SERS considering POCT requirements. From the detection ranges reported in the reviewed literature, we suggest the diseases other than AMI that could be diagnosed with this technique. For this, a section with information about cardiac and non-cardiac diseases with cTnI release, including their release kinetics or cut-off values are presented. Likewise, POCT features, the use of SERS as a POCT technique, and the biochemistry of cTnI are discussed. The information provided in this review allowed the identification of strengths and lacks of the available SERS-based point-of-care tests for cTnI and the disclosing of requirements for future assays design.

High-sensitivity cardiac troponin and the diagnosis of myocardial infarction in patients with kidney impairment

The benefit and utility of high-sensitivity cardiac troponin (hs-cTn) in the diagnosis of myocardial infarction in patients with kidney impairment is unclear. Here, we describe implementation of hs-cTnI testing on the diagnosis, management, and outcomes of myocardial infarction in patients with and without kidney impairment. Consecutive patients with suspected acute coronary syndrome enrolled in a stepped-wedge, cluster-randomized controlled trial were included in this pre-specified secondary analysis. Kidney impairment was defined as an eGFR under 60mL/min/1.73m2. The index diagnosis and primary outcome of type 1 and type 4b myocardial infarction or cardiovascular death at one year were compared in patients with and without kidney impairment following implementation of hs-cTnI assay with 99th centile sex-specific diagnostic thresholds. Serum creatinine concentrations were available in 46,927 patients (mean age 61 years; 47% women), of whom 9,080 (19%) had kidney impairment. hs-cTnIs were over 99th centile in 46% and 16% of patients with and without kidney impairment. Implementation increased the diagnosis of type 1 infarction from 12.4% to 17.8%, and from 7.5% to 9.4% in patients with and without kidney impairment (both significant). Patients with kidney impairment and type 1 myocardial infarction were less likely to undergo coronary revascularization (26% versus 53%) or receive dual anti-platelets (40% versus 68%) than those without kidney impairment, and this did not change post-implementation. In patients with hs-cTnI above the 99th centile, the primary outcome occurred twice as often in those with kidney impairment compared to those without (24% versus 12%, hazard ratio 1.53, 95% confidence interval 1.31 to 1.78). Thus, hs-cTnI testing increased the identification of myocardial injury and infarction but failed to address disparities in management and outcomes between those with and without kidney impairment.

Chronic Renal Failure and Cardiovascular Disease: A Comprehensive Appraisal

Coronary artery disease is highly prevalent in patients with chronic kidney disease. The concomitant renal disease often poses a major challenge in decision making as symptoms, cardiac biomarkers and noninvasive studies for evaluation of myocardial ischemia have different sensitivity and specificity thresholds in this specific population. Moreover, the effectiveness and safety of intervention and medical treatment in those patients is of great doubt as most clinical studies exclude patients with advance CKD. In the present paper, we discuss and review the literature in the diagnosis, treatment and prevention of CAD in the acute and chronic setting, in patients with CKD.

Prognostic Value of β1 Adrenergic Receptor Autoantibody and Soluble Suppression of Tumorigenicity-2 in Patients With Acutely Decompensated Heart Failure

Background

Both β1 adrenergic receptor autoantibody (β1-AA) and soluble suppression of tumorigenicity-2 (sST2) take a role in the pathological remodeling of heart failure. However, limited studies investigated the correlation between the expression of β1-AA and sST2 in patients with acutely decompensated heart failure (ADHF).

Objective

To explore the correlation between β1-AA and sST2, and evaluate their prognostic value in patients with ADHF.

Methods

Patients who were admitted for ADHF were included. The N-terminal pro-brain natriuretic peptide (NT-proBNP), sST2, and β1-AA in blood samples were tested at hospital admission and then followed up for assessing the outcomes. Pearson correlation analysis was used to explore the correlation between β1-AA and sST2. The effects of β1-AA, sST2, or the combination of them on the all-cause mortality of patients with ADHF were assessed by Multivariate Cox regression analysis.

Results

There were 96 patients with ADHF and 96 control populations enrolled. The β1-AA was significantly higher in ADHF than in the control group (0.321 ± 0.06 vs. 0.229 ± 0.04, P = 0.000). Pearson correlation analysis showed that β1-AA was positively correlated with sST2 (r = 0.593), NT-proBNP (r = 0.557), Procalcitonin (r = 0.176), and left ventricular end-diastolic diameter (r = 0.315), but negatively correlated with triglycerides (r = −0.323), and left ventricular ejection fraction (r = −0.430) (all P < 0.05) in ADHF. Patients with ADHF, complicated with both high β1-AA and sST2, showed the highest all-cause mortality during an average of 25.5 months of follow-up. Multivariate Cox regression showed the combination of both high β1-AA and sST2 independently correlated with the all-cause mortality after adjustment for other risk factors (hazard ratio 3.348, 95% CI 1.440 to 7.784, P = 0.005). After adding with β1-AA and sST2, the area under the curves for the prognostic all-cause mortality could increase from 0.642 to 0.748 (P = 0.011).

Conclusion

The β1-AA is positively correlated with sST2 in patients with ADHF. Elevated plasma β1-AA and sST2 level in patients with ADHF are associated with poorer prognoses.

Chronic kidney disease and risk of atrial fibrillation and heart failure in general population-based cohorts: the BiomarCaRE project

AIMS

Chronic kidney disease (CKD) has a complicated relationship with the heart, leading to many adverse outcomes. The aim of this study was to evaluate the relationship between CKD and the incidence of atrial fibrillation (AF) and heart failure (HF) along with mortality as a competing risk in general population cohorts. We also included an assessment of baseline biomarkers of inflammation, myocardial injury, and left ventricular dysfunction with risk of AF and HF, respectively, to shed light on the potential underlying pathophysiology.

METHODS AND RESULTS

This study was conducted within the BiomarCaRE project using harmonized data from 12 European population-based cohorts (n = 48 518 participants). Renal function was assessed by glomerular filtration rate estimated using the combined Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation with standardized serum creatinine (Cr) and non-standardized serum cystatin C (CysC). Incidence of AF and HF respectively, during a median follow-up of 8 years was recorded. Cox proportional hazards models were used to determine hazard ratios (HRs) for the incidence of AF and HF in CKD and the competing risk of mortality after adjustment for covariates. The mean age at baseline was 51.4 (standard deviation 12.1) years, 49% were men. Overall, 4.3% of subjects had CKD at baseline. The rate for AF was 3.8 per 1000 person-years during follow-up. The HR for AF in patients with CKD compared with patients without CKD was 1.28 (95% confidence interval 1.07-1.54) after adjustment for covariates. The rate for incident HF was 4.1 per 1000 person-years and the HR of CKD for HF was 1.71 (95% confidence interval 1.45-2.01. In subjects with CKD, N-terminal-pro-brain natriuretic peptide (NT-proBNP) showed an association with AF, whereas NT-proBNP and C-reactive protein were associated with HF.

CONCLUSIONS

Chronic kidney disease is an independent risk factor for subsequent AF and is even more closely associated with HF. In these relatively young participants with CKD, NT-proBNP was strongly associated with subsequent risk of AF. For HF, in addition, elevated levels of hs-C-reactive protein at baseline were related to incident events.

Routinely measured cardiac troponin I and N-terminal pro-B-type natriuretic peptide as predictors of mortality in haemodialysis patients

Aims

Cardiac troponin (cTn) and B‐type natriuretic peptide (BNP) are elevated in haemodialysis (HD) patients, and this elevation is associated with HD‐induced myocardial stunning/myocardial strain. However, studies using data from the international Dialysis Outcomes and Practice Patterns Study (DOPPS) have shown that these cardiac biomarkers are measured in <2% of HD patients in real‐world practice. This study aimed to examine whether routinely measured N‐terminal pro‐BNP (NT‐proBNP) and cTnI (contemporary assay) are more appropriate than clinical models for reclassifying the risk of HD patients who have the highest risk of death.

Methods and results

Pre‐dialysis levels of cTnI and NT‐proBNP at study enrolment were measured in 1152 HD patients (Japan DOPPS Phase 5). The patients were prospectively followed for 3 years. Cox regression was used to test the associations of cardiac biomarkers with all‐cause mortality, adjusting for potential confounders. Subgroup analyses were performed to assess potential effect modification of clinical characteristics, such as age, systolic blood pressure, HD vintage, diabetes mellitus, coronary artery disease, and a history of congestive heart failure. At baseline, 337 (29%) patients had elevated cTnI (99th percentile of a healthy population: >0.04 ng/mL) with a median (inter‐quartile range) level of 0.020 (0.005–0.041) ng/mL, and 1140 (99%) patients had elevated NT‐proBNP (cut‐off for heart failure: >125 pg/mL) with a median level of 3658 (1689–9356) pg/mL. There were 167 deaths during a median follow‐up of 2.8 (2.2–2.8) years. Higher levels of both cardiac biomarkers were incrementally associated with mortality after adjustment for potential confounders. Even after adjustment for alternative cardiac biomarkers, the overall P value for the association was <0.01 for both biomarkers. However, the prognostic significance of NT‐proBNP was moderately diminished when cTnI was added to the model. The hazard ratios of mortality for cTnI > 0.04 ng/mL (vs. cTnI < 0.006 ng/mL) and NT‐proBNP > 8000 pg/mL (vs. NT‐proBNP < 2000 pg/mL) were 2.56 (95% confidence interval: 1.37–4.81) and 1.90 (95% confidence interval: 0.95–3.79), respectively. Subgroup analyses showed that the associations of both cardiac biomarkers with mortality were generally consistent between stratified groups.

Conclusions

Routinely measured NT‐proBNP and cTnI levels are strongly associated with mortality among prevalent HD patients. These associations remain robust, even after adjustment for alternative biomarkers, suggesting that cTnI and NT‐proBNP have identical prognostic significance and may reflect different pathological aspects of cardiac abnormalities.

Elderly patients with non-cardiac admissions and elevated high-sensitivity troponin: the prognostic value of renal function

BACKGROUND

High-sensitivity cardiac troponin (hs-cTn) levels are frequently elevated in elderly patients presenting to the emergency department for non-cardiac events. However, most studies on the role of elevated hs-cTn in elderly populations have investigated the prognostic value of hs-cTn in patients with a specific diagnosis or have assessed the relationship between hs-cTn and comorbidities.

AIM

To investigate the in-hospital prognosis of consecutive elderly patients admitted to the Internal Medicine Department with acute non-cardiac events and increased hs-cTnI levels.

METHODS

In this retrospective study, we selected patients who were aged ≥ 65 years and admitted to the Internal Medicine Department of our hospital between January 2019 and December 2019 for non-cardiac reasons. Eligible patients were those who had hs-cTnI concentrations ≥ 100 ng/L. We investigated the independent predictors of in-hospital mortality by multivariable logistic regression analysis.

RESULTS

One hundred and forty-six patients (59% female) were selected with an age range from 65 to 100 (mean ± SD: 85.4 ± 7.61) years. The median hs-cTnI value was 284.2 ng/L. For 72 (49%) patients the diagnosis of hospitalization was an infectious disease. The overall in-hospital mortality was 32% (47 patients). Individuals who died did not have higher hs-cTnI levels compared with those who were discharged alive (median: 314.8 vs 282.5 ng/L; P = 0.565). There was no difference in mortality in patients with infectious vs non-infectious disease (29% vs 35%). Multivariable analysis showed that age (OR 1.062 per 1 year increase, 95%CI: 1.000-1.127; P = 0.048) and creatinine levels (OR 2.065 per 1 mg/dL increase, 95%CI: 1.383-3.085; P < 0.001) were the only independent predictors of death. Mortality was 49% in patients with eGFR < 30 mL/min/1.73 m².

CONCLUSION

Myocardial injury is a malignant condition in elderly patients admitted to the hospital for non-cardiac reasons. The presence of severe renal impairment is a marker of extremely high in-hospital mortality.

The Main Causes and Mechanisms of Increase in Cardiac Troponin Concentrations Other Than Acute Myocardial Infarction (Part 1): Physical Exertion, Inflammatory Heart Disease, Pulmonary Embolism, Renal Failure, Sepsis

The causes and mechanisms of increased cardiac troponin T and I (cTnT and cTnI) concentrations are numerous and are not limited to acute myocardial infarction (AMI) (ischemic necrosis of cardiac myocytes). Any type of reversible or irreversible cardiomyocyte injury can result in elevated serum cTnT and cTnI levels. Researchers and practitioners involved in the diagnosis and treatment of cardiovascular disease, including AMI, should know the key causes and mechanisms of elevated serum cTnT and cTnI levels. This will allow to reduce or completely avoid diagnostic errors and help to choose the most correct tactics for further patient management. The purpose of this article is to discuss the main causes and mechanisms of increase in cardiac troponins concentrations in frequently occurring physiological (physical exertion, psycho-emotional stress) and pathological conditions (inflammatory heart disease, pulmonary embolism, chronic renal failure and sepsis (systemic inflammatory response)) not related to myocardial infarction.

High-Sensitivity Cardiac Troponin T in Patients with Severe Chronic Kidney Disease and Suspected Acute Coronary Syndrome

(1) Background: Patients with severe chronic kidney disease (CKD G4-G5) often have chronically elevated high-sensitivity cardiac troponin T (hs-cTnT) values above the 99th percentile of the upper reference limit. In these patients, optimal cutoff levels for diagnosing non-ST-elevation acute coronary syndrome (NSTE-ACS) requiring revascularization remain undefined. (2) Methods: Of 11,912 patients undergoing coronary angiography from 2012 to 2017 for suspected NSTE-ACS, 325 (3%) had severe CKD. Of these, 290 with available serial hs-cTnT measurements were included, and 300 matched patients with normal renal function were selected as a control cohort. (3) Results: In the CKD cohort, 222 patients (76%) had NSTE-ACS with indication for coronary revascularization. Diagnostic performance was high at presentation and similar to that of the control population (AUC, 95% CI: 0.81, 0.75-0.87 versus 0.85, 0.80-0.89, p = 0.68), and the ROC-derived cutoff value was 4 times higher compared to the conventional 99th percentile. Combining the ROC-derived cutoff levels for hs-cTnT at presentation and absolute 3 h changes, sensitivity increased to 98%, and PPV and NPV improved up to 93% and 86%, respectively. (4) Conclusions: In patients with severe CKD and suspected ACS, the diagnostic accuracy of hs-cTnT for the diagnosis of NSTE-ACS requiring revascularization is improved by using higher assay-specific cutoff levels combined with early absolute changes.

Elevation Mechanisms and Diagnostic Consideration of Cardiac Troponins under Conditions Not Associated with Myocardial Infarction. Part 1

Although cardiac troponins are considered the most specific biomarkers for the diagnosis of acute myocardial infarction (AMI), their diagnostic consideration goes far beyond the detection of this dangerous disease. The mechanisms of cardiac troponin elevation are extremely numerous and not limited to ischemic necrosis of cardiac myocytes. Practitioners should be well aware of the underlying pathological and physiological conditions that can lead to elevated serum levels of cardiac troponins to avoid differential diagnostic errors, which will be greatly increased if clinicians rely on laboratory data alone. This article presents a classification of the main causes of an elevation in cardiac troponins and discusses in detail the mechanisms of such elevation and the diagnostic consideration of cardiac troponins in some conditions not associated with AMI, such as physical exertion, inflammatory heart diseases (myocarditis and endocarditis), pulmonary embolism (PE), renal failure, and systemic inflammation (sepsis).

The cardiovascular-dialysis nexus: the transition to dialysis is a treacherous time for the heart

Chronic kidney disease (CKD) patients require dialysis to manage the progressive complications of uraemia. Yet, many physicians and patients do not recognize that dialysis initiation, although often necessary, subjects patients to substantial risk for cardiovascular (CV) death. While most recognize CV mortality risk approximately doubles with CKD the new data presented here show that this risk spikes to >20 times higher than the US population average at the initiation of chronic renal replacement therapy, and this elevated CV risk continues through the first 4 months of dialysis. Moreover, this peak reflects how dialysis itself changes the pathophysiology of CV disease and transforms its presentation, progression, and prognosis. This article reviews how dialysis initiation modifies the interpretation of circulating biomarkers, alters the accuracy of CV imaging, and worsens prognosis. We advocate a multidisciplinary approach and outline the issues practitioners should consider to optimize CV care for this unique and vulnerable population during a perilous passage.

Relationships between renal function variations and relative changes in cardiac troponin T concentrations based on quantile generalized additive models (qgam)

OBJECTIVES

The relationship between high-sensitive cardiac troponin T concentration (hs-cTnT) and renal markers levels is known. However, the extent to which their variations are associated remains to be explored. Objective: model the relationship between relative changes in hs-cTnT (Δhs-cTnT) and variations in creatinine (Δcre) or estimated glomerular filtration rate (ΔeGFR), using a quantile generalized additive model (qgam).

METHODS

Concomitant plasma Δhs-cTnT and Δcre from patients aged 18-100 years, selected with a time variation (Δtime) of 3 h-7 days, were collected over a 5.8-year period. Relationships between Δhs-cTnT and covariates Δcre (A) or ΔeGFR (B), including age, Δtime, hour of blood sampling (HSB) and covariates interactions were fitted using qgam.

RESULTS

On the whole (n=106567), Δhs-cTnT was mainly associated with Δcre, in a positive and nonlinear way (-21, -6, +5, +20, +55% for -50, -20, +20, +50, +100%, respectively), but to a lesser extent with age (min -9%, max +2%), Δtime (min -4%, max +8%), and HSB (min -5%, max +7%). Δhs-cTnT was negatively associated with ΔeGFR (+46, +7, -5, -11, -20% for -50, -20, +20, +50, +100%, respectively). Classifying Δhs-cTnT as consistent or not with myocardial injury based on recommendations, an interpretation of Δhs-cTnT adjusted for model A or B led to statistically significant but small diagnostic discrepancies (<2%), as compared to an interpretation based on Δhs-cTnT only.

CONCLUSIONS

From a laboratory and statistical standpoint, considering renal function variations when interpreting relative changes in cardiac troponin T has a minor impact on the diagnosis rate of myocardial injury.

Value of the high-sensitivity troponin T assay for diagnosis of acute myocardial infarction in patients with and without renal insufficiency

BACKGROUND

Cardiac troponins are important markers for diagnosis of acute myocardial infarction (AMI) in general population; however, chronically-elevated troponins levels are often seen in patients with renal insufficiency, which reduce their diagnostic accuracy. The aim of our study was to access the diagnostic values of initial high-sensitive cardiac troponin T (hs-cTnT) and relative change of hs-cTnT for AMI in patients with and without renal insufficiency.

METHODS

Cardiac care unit patients with elevated hs-cTnT levels in 2017-2018 were enrolled. Receiver operating characteristic (ROC) curves were used to evaluate initial hs-cTnT levels and relative changes after 3 h of enrollment for diagnosis of AMI in patients with estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² (low), and eGFR ≥ 60 mL/min/1.73 m² (normal).

RESULTS

Of 359 patients, 240 patients had low eGFR, and 119 patients had normal eGFR. The area under the ROC curve (AUC) for the initial hs-cTnT levels was 0.58 (95% CI, 0.5-0.65, p = 0.053) among patients with low eGFR and 0.54 (95% CI, 0.4-0.67, p = 0.612) among patients with normal eGFR. AUCs for relative changes of hs-cTnT were 0.82 (95% CI, 0.76-0.88, p < 0.001) in patients with low eGFR and 0.82 (95% CI, 0.71-0.91, p < 0.001) in patients with normal eGFR. Optimal cutoff values for the relative changes in hs-cTnT were 16% and 12% in patients with low eGFR and normal eGFR, respectively.

CONCLUSIONS

Relative changes in hs-cTnT levels had better diagnostic accuracy than initial hs-cTnT levels.

BNP and NT-proBNP Interpretation in the Neprilysin Inhibitor Era

PURPOSE OF REVIEW

Describe the mechanisms that may influence change in measured natriuretic peptide levels when using the neprilysin inhibitor sacubitril to treat a patient with heart failure.

RECENT FINDINGS

Prior to the introduction of the neprilysin inhibitor sacubitril as part of a chemical combination with the angiotensin receptor blocker valsartan shown to reduce mortality and heart failure hospitalizations in patients with heart failure with reduced ejection fraction, the natriuretic peptide assays for B-type natriuretic peptide (BNP) and the amino-terminal proBNP (NT-proBNP) assays were shown to have similar diagnostic accuracy to differentiate heart failure from other etiologies of shortness of breath. Sacubitril/valsartan use has been shown to result in a modest and chronic elevation of BNP while reducing levels of NT-prBNP. This review explores the potential impact of these findings on interpreting natriuretic peptide results for diagnosis and prognosis, as well as explore the challenges associated with the heterogeneity of this finding, highlighting the impact of inhibiting neprilysin, a non-specific endopeptidase with multiple target sites within BNP and other proteins. With increased uptake of sacubitril/valsartan expected in patients with heart failure, interpretation of natriuretic peptide assays becomes somewhat more complex, particularly for BNP. However, knowing a baseline steady-state concentration and using the same assay can assist with BNP interpretation for diagnosis and prognosis.

Do Natriuretic Peptide Measurements Provide Insights into Management of End-Stage Renal Disease Patients Undergoing Dialysis?

PURPOSE OF REVIEW

Impaired renal function may affect natriuretic peptide levels through a variety of factors and mechanisms, such as high prevalence of concomitant vascular and myocardial diseases, reduced clearance, increased risk of volume overload, and different types and solute removal techniques in the setting of dialysis. Nevertheless, accumulating evidence suggests that natriuretic peptide testing may provide insights into management of patients with chronic kidney disease (CKD) and end-stage kidney disease (ESRD) on dialysis, as they have been shown to be independently associated with morbidity and mortality.

RECENT FINDINGS

Rising natriuretic peptide levels over time may identify CKD patients more likely to approach ESRD and requiring dialysis initiation. Moreover, serial natriuretic peptide measurements may also be helpful in guiding fluid management in ESRD patients on dialysis. However, since patients with CKD usually have significantly higher and more variable baseline levels of natriuretic peptides than those without CKD, traditional cut-off values may not be applicable, and individualized trajectories should be applied and interpreted in the clinical context. Routine clinical use natriuretic peptide testing in the CKD and ESRD settings still needs to be refined and individualized, yet their diagnostic and prognostic values can provide valuable insights into clinical trajectories and potential treatment responses.

Clinical risk assessment of biotin interference with a high-sensitivity cardiac troponin T assay

Objectives

Biotin >20.0 ng/mL (81.8 nmol/L) can reduce Elecsys® Troponin T Gen 5 (TnT Gen 5; Roche Diagnostics) assay recovery, potentially leading to false-negative results in patients with suspected acute myocardial infarction (AMI). We aimed to determine the prevalence of elevated biotin and AMI misclassification risk from biotin interference with the TnT Gen 5 assay.

Methods

Biotin was measured using an Elecsys assay in two cohorts: (i) 797 0-h and 646 3-h samples from 850 US emergency department patients with suspected acute coronary syndrome (ACS); (ii) 2023 random samples from a US laboratory network, in which biotin distributions were extrapolated for higher values using pharmacokinetic modeling. Biotin >20.0 ng/mL (81.8 nmol/L) prevalence and biotin 99th percentile values were calculated. AMI misclassification risk due to biotin interference with the TnT Gen 5 assay was modeled using different assay cutoffs and test timepoints.

Results

ACS cohort: 1/797 (0.13%) 0-h and 1/646 (0.15%) 3-h samples had biotin >20.0 ng/mL (81.8 nmol/L); 99th percentile biotin was 2.62 ng/mL (10.7 nmol/L; 0-h) and 2.38 ng/mL (9.74 nmol/L; 3-h). Using conservative assumptions, the likelihood of false-negative AMI prediction due to biotin interference was 0.026% (0-h result; 19 ng/L TnT Gen 5 assay cutoff). US laboratory cohort: 15/2023 (0.74%) samples had biotin >20.0 ng/mL (81.8 nmol/L); 99th percentile biotin was 16.6 ng/mL (68.0 nmol/L). Misclassification risk due to biotin interference (19 ng/L TnT Gen 5 assay cutoff) was 0.025% (0-h), 0.0064% (1-h), 0.00048% (3-h), and <0.00001% (6-h).

Conclusions

Biotin interference has minimal impact on the TnT Gen 5 assay’s clinical utility, and the likelihood of false-negative AMI prediction is extremely low.

Impact of Kidney Function on the Blood Proteome and on Protein Cardiovascular Risk Biomarkers in Patients With Stable Coronary Heart Disease

Background

Chronic kidney disease (CKD) confers increased cardiovascular risk, not fully explained by traditional factors. Proteins regulate biological processes and inform the risk of diseases. Thus, in 938 patients with stable coronary heart disease from the Heart and Soul cohort, we quantified 1054 plasma proteins using modified aptamers (SOMAscan) to: (1) discern how reduced glomerular filtration influences the circulating proteome, (2) learn of the importance of kidney function to the prognostic information contained in recently identified protein cardiovascular risk biomarkers, and (3) identify novel and even unique cardiovascular risk biomarkers among individuals with CKD.

Methods and Results

Plasma protein levels were correlated to estimated glomerular filtration rate (eGFR) using Spearman‐rank correlation coefficients. Cox proportional hazard models were used to estimate the association between individual protein levels and the risk of the cardiovascular outcome (first among myocardial infarction, stroke, heart failure hospitalization, or mortality). Seven hundred and nine (67.3%) plasma proteins correlated with eGFR at P<0.05 (ρ 0.06–0.74); 218 (20.7%) proteins correlated with eGFR moderately or strongly (ρ 0.2–0.74). Among the previously identified 196 protein cardiovascular biomarkers, just 87 remained prognostic after correction for eGFR. Among patients with CKD (eGFR <60 mL/min per 1.73 m²), we identified 21 protein cardiovascular risk biomarkers of which 8 are unique to CKD.

Conclusions

CKD broadly alters the composition of the circulating proteome. We describe protein biomarkers capable of predicting cardiovascular risk independently of glomerular filtration, and those that are prognostic of cardiovascular risk specifically in patients with CKD and even unique to patients with CKD.

Impact of comorbidities on peak troponin levels and mortality in acute myocardial infarction

OBJECTIVES

To characterise peak cardiac troponin levels, in patients presenting with acute myocardial infarction (AMI), according to their comorbid condition and determine the influence of peak cardiac troponin (cTn) levels on mortality.

METHODS

We included patients with the first admission for AMI in the UK. We used linear regression to estimate the association between eight common comorbidities (diabetes mellitus, previous angina, peripheral arterial disease, previous myocardial infarction (MI), chronic kidney disease (CKD), cerebrovascular disease, chronic heart failure (CHF) and chronic obstructive pulmonary disease (COPD)) and peak cTn. Peak cTn levels were adjusted for age, sex, smoking status and comorbidities. Logistic regression and restricted cubic spline models were employed to investigate the association between peak cTn and 180-day mortality for each comorbidity.

RESULTS

330 367 patients with ST elevation myocardial infarction and non-ST elevation myocardial infarction were identified. Adjusted peak cTn levels were significantly higher in patients with CKD (adjusted % difference in peak cTnT for CKD=42%, 95% CI 13.1 to 78.4) and significantly lower for patients with COPD, previous angina, previous MI and CHF when compared with patients without the respective comorbidities (reference group) (cTnI; COPD=-21.7%, 95% CI -29.1 to -13.4; previous angina=-24.2%, 95% CI -29.6 to -8.3; previous MI=-13.5%, 95% CI -20.6 to -5.9; CHF=-28%, 95% CI -37.2 to -17.6). Risk of 180-day mortality in most of the comorbidities did not change substantially after adjusting for peak cTn. In general, cTnI had a stronger association with mortality than cTnT.

CONCLUSIONS

In this nationwide analysis of patients presenting with AMI, comorbidities substantially influenced systemic concentrations of peak cTn. Comorbid illness is a significant predictor of mortality regardless of peak cTn levels and should be taken into consideration while interpreting cTn both as a diagnostic and prognostic biomarker.

Evaluation of the Relationship between Early Troponin Clearance and Short-Term Mortality in Patients with Chronic Renal Failure

Objective

In patients with CKD, cTn concentrations may be elevated in the absence of AMI, which is a predicted finding caused by chronic structural heart disease rather than acute injury. The increase in troponin level observed in noncardiac conditions provides conflicting results when predicting mortality. Low lactate clearance was associated with increased mortality. Lactate clearance is calculated as follows: (early lactate - late lactate/early lactate) ∗ 100. We aimed to investigate whether troponin clearance calculated according to this formula had an effect on short-term mortality.

Methods

The study included 300 patients with chronic renal failure who had a sepsis-related organ failure assessment (SOFA) score ≥3. By taking the baseline troponin at the time of emergency presentation as reference and comparing them with the fourth-hour troponin values, troponin clearance was investigated in the evaluation of mortality among hospitalized patients with CKD within the first month after discharge. The data obtained were analyzed using the SPSS data analysis software version 20.0. Student's t-test was used for the parametric data, and the Chi-squared test for the nonparametric data.

Results

Of the 300 patients evaluated, 189 patients survived (mean age 66.20 ± 14.597 years), and 111 died (mean age 74.81 ± 12.916 years). Troponin clearance was detected in 40 of the 111 patients in the mortality group and 119 of the 189 patients in the survival group. Troponin clearance was significantly more frequent in surviving patients (P=0.0000083).

Conclusion

Troponin clearance can be considered as a valuable leading indicator of survival, but higher levels of troponin clearance did not lead to higher survival rates.

Preliminary investigation of serum cardiac troponin I in dogs with acute ischaemic stroke

OBJECTIVES

To describe the incidence of elevated serum cardiac troponin I in dogs with acute ischaemic strokes, to evaluate its prognostic value in these patients and characterise a possible relationship between cardiac troponin I elevation in dogs with ischaemic strokes and underlying cardiac dysfunction.

MATERIALS AND METHODS

Prospective study of 18 dogs with acute ischaemic stroke diagnosed by MRI of the brain. Serum cardiac troponin I concentration, trans-thoracic echocardiography and six-lead electrocardiography were performed and findings were compared between dogs with good and poor outcome.

RESULTS

Serum cardiac troponin I was increased in 17 dogs (median 0.95 ng/mL; range 0.146 to 153). Focal hyperechoic regions of myocardium were visible in two dogs using trans-thoracic echocardiography and presumed to represent acute infarcts. A significant association was found between cardiac troponin I and creatinine concentrations. No difference in cardiac troponin I concentrations was detected between dogs that experienced good and poor outcomes. Clinically important cardiac dysfunction was identified in two dogs.

CLINICAL SIGNIFICANCE

Cardiac troponin I is commonly elevated in patients diagnosed with acute ischaemic stroke but, in this small study population, did not have prognostic value. Larger studies (recruiting a study population of 98 dogs for a power of 0.8 and a 0.05 alpha/critical value) would aid in further investigation of these preliminary results.

Circulating Long Noncoding RNA LIPCAR Predicts Heart Failure Outcomes in Patients Without Chronic Kidney Disease

The plasma levels of long noncoding RNA LIPCAR are elevated in heart failure (HF) patients with reduced ejection fraction and associated with left ventricular remodeling and poor outcomes. We studied whether the presence of chronic kidney disease (CKD), as defined by an estimated glomerular filtration rate value <60mL/(min·1.73m2) modified the associations of plasma LIPCAR with left ventricular remodeling and outcomes in HF patients. Two hundred and thirty-four patients (mean age 74 [9.14] years, 50% male) were enrolled and followed for 4.73 (0.24-7.25) years. Plasma LIPCAR was detected by real-time quantitative polymerase chain reaction. LIPCAR was increased ( P=0.005) in patients compared with 17 age- and sex-matched controls, directly correlated with age ( P=0.001) and with the maximal early transmitral flow velocity to the mean peak early diastolic velocity of the mitral annulus displacement ratio ( P=0.001) and inversely correlated with estimated glomerular filtration rate ( P<0.001). LIPCAR was associated with hospitalization for HF, cardiovascular death, and a composite of hospitalization for HF or cardiovascular death ( P≤0.010), these associations being dependent of estimated glomerular filtration rate. The interactions between estimated glomerular filtration rate and LIPCAR with respect to these outcomes were statistically significant or of borderline significance ( P≤0.060). LIPCAR was increased in CKD patients compared with non-CKD patients ( P=0.021). LIPCAR was independently associated with hospitalization for HF ( P≤0.039) only in non-CKD patients, but its addition to traditional risk factors did not improve risk prediction in these patients. In conclusion, plasma LIPCAR prognosticates outcomes in elderly HF patients without CKD. Thus, there is an effect modification of CKD on the association of circulating LIPCAR with outcomes in HF patients.

Educational Recommendations on Selected Analytical and Clinical Aspects of Natriuretic Peptides with a Focus on Heart Failure: A Report from the IFCC Committee on Clinical Applications of Cardiac Bio-Markers

The IFCC Committee on Clinical Applications of Cardiac Bio-Markers (C-CB) has directives and initiatives focused on providing evidence-based educational resources to aid and improve understanding around key analytical and clinical aspects of cardiac biomarkers used in clinical practice and the research setting. As a task force, we have previously published position statements and recommendations focused on use and analytical aspects of high-sensitivity cardiac troponin assays. The current educational document is the first from the C-CB highlighting important biochemical, analytical, and clinical aspects as they relate to the natriuretic peptides (NPs), including B-type natriuretic peptide (BNP) and N-terminal pro–B-type natriuretic peptide (NT-proBNP), with a focus on heart failure.

The Confounding Effects of Non-cardiac Pathologies on the Interpretation of Cardiac Biomarkers

PURPOSE OF REVIEW

Cardiac biomarkers play important roles in routine evaluation of cardiac patients. But while these biomarkers can be extremely valuable, none of them should ever be used by themselves-without adding the clinical context. This paper explores the non-cardiac pathologies that can be seen with the cardiac biomarkers most commonly used.

RECENT FINDINGS

High-sensitivity troponin assay gained FDA approval for use in the USA, and studies demonstrated its diagnostic utility can be extended to patients with renal impairment. Gender-specific cut points may be utilized for high-sensitivity troponin assays. In the realm of the natriuretic peptides, studies demonstrated states of natriuretic peptide deficiency in obesity and in subjects of African-American race. Regardless, BNP and NT-proBNP both retained prognostic utilities across a variety of comorbid conditions. We are rapidly gaining clinical evidence with use of soluble ST2 and procalcitonin levels in management of cardiac disease states. In order to get the most utility from their measurement, one must be aware of non-cardiac pathologies that may affect the levels of biomarkers as although many of these are actually true values, they may not represent the disease we are trying to delineate. A few take-home points are as follows: 1. A biomarker value should never be used without clinical context 2. Serial sampling of biomarkers is often helpful 3. Panels of biomarkers may be valuable.

Performance analysis of AL amyloidosis cardiac biomarker staging systems with special focus on renal failure and atrial arrhythmia

Systemic light chain amyloidosis is a rare and life-threatening disorder, for which accurate risk stratification is crucial. Current cardiac staging systems (MAYO2004, MAYO3b, and MAYO2012) are mainly based on biomarkers, which have uncertain reliability in the context of atrial fibrillation, arrhythmia or pacemaker stimulation as well as renal insufficiency. We compared the performance of the established staging systems with particular regard to these comorbidities in 1,224 patients with systemic light chain amyloidosis diagnosed at our center from July 2002 until March 2017. We first characterized the subsets with an estimated glomerular filtration rate <50 mL/min/1.73 m² (415 patients) and any kind of atrial arrhythmia (183 patients) as unique high-risk subgroups with similarly increased cardiac biomarkers (χ²-test, all P<0.001). This resulted in a shift towards higher risk stages and reduced median overall survival compared to those of patients with better kidney function or without atrial arrhythmia in univariate analyses (13 vs. 46 months and 17 vs. 53 months, respectively; both P<0.001). Performance analysis revealed that predictions in the entire cohort were least precise with the MAYO2004 staging system and most precise with the MAYO3b system. This performance pattern was almost preserved for patients with an estimated glomerular filtration rate <50 mL/min/1.73 m², but less so for those with atrial arrhythmias. The MAYO3b staging system was most robust. Importantly, atrial arrhythmia retained its prognostic value in multivariable analysis including age, difference between involved and uninvolved free light chains, and any staging system, while estimated glomerular filtration rate <50 mL/min/1.73 m² was not statistically significant in multivariable analysis with the MAYO3b staging system. In conclusion, our results favor the MAYO3b staging system due to its consistently best performance and retained applicability in the subgroups with atrial arrhythmia and estimated glomerular filtration rate <50 mL/min/1.73 m².

Cardiac Troponin - diagnostic problems and impact on cardiovascular disease

The definition of a high-sensitivity cardiac Troponin (cTn) assay describes the ability to quantify a cardiac biomarker level in at least 50% of healthy individuals. This advance in analytic sensitivity has come with a perceived loss of specificity in the most classic application - chest pain triage and the diagnosis of acute myocardial infarction (AMI). As cardiac Troponin can no longer be used as a dichotomous test, the medical field is increasingly moving towards a more granular interpretation. However, rapid rule-out/rule-in algorithms for AMI still rely on concrete thresholds for efficient triage, irrespective of the patient's comorbidities. Owing to a slightly elevated cTn value, evermore patients appear to fall into an indeterminate risk zone of diagnostic uncertainty. The reasons are manifold, spanning biological variation, analytical issues, increased plasma membrane permeability and the potential cytosolic release of cTn. This review provides a contemporary overview of the literature concerning the use of cardiac Troponin in chronic and acute cardiovascular care. Key messages High-sensitivity cardiac Troponin assays have transformed the assessment of cardiovascular disease. Rapid rule-out algorithms for chest pain triage have become increasingly complicated, but enable safe rule-out. Cardiac Troponin tracks mid- to long-term risk in patients with hyperlipidaemia, heart failure and renal dysfunction.

Oxidative Stress and Cardiovascular Complications in Chronic Kidney Disease, the Impact of Anaemia

Patients with chronic kidney disease (CKD) have significant cardiovascular morbidity and mortality as a result of risk factors such as left ventricular hypertrophy (LVH), oxidative stress, and inflammation. The presence of anaemia in CKD further increases the risk of LVH and oxidative stress, thereby magnifying the deleterious consequence in uraemic cardiomyopathy (UCM), and aggravating progression to failure and increasing the risk of sudden cardiac death. This short review highlights the specific cardio-renal oxidative stress in CKD and provides an understanding of the pathophysiology and impact of uraemic toxins, inflammation, and anaemia on oxidative stress.

The impact of renal function on the prognostic value of N-terminal pro-B-type natriuretic peptide in patients with coronary artery disease

BACKGROUND

The impact of renal function on the prognostic value of N-terminal pro-B-type natriuretic peptide (NT-proBNP) remains unclear in coronary artery disease (CAD). This study sought to investigate the value of using NT-proBNP level to predict prognoses of CAD patients with different estimated glomerular filtration rates (eGFRs).

METHODS

A retrospective analysis was conducted from a single registered database. 2087 consecutive patients with CAD confirmed by coronary angiography were enrolled. The primary endpoint was allcause mortality.

RESULTS

The mean follow-up time was 26.4 ± 11.9 months and death events occurred in 197 cases. The NT-proBNP levels increased with the deterioration of renal function, as well as the optimal cutoff values based on eGFR stratification to predict endpoint outcome (179.4 pg/mL, 1443.0 pg/mL, 3478.0 pg/mL, for eGFR ≥ 90, 60-90 and < 60 mL/min/1.73 m2, respectively). Compared with the routine cut-off value or overall optimal one, stratified optimal ones had superior predictive ability for endpoint in each eGFR group (all with the highest Youden's J statistics). And the prognostic value became weaker as eGFR level decreased (eGFR ≥ 90 vs. 60-90 vs. < 60 mL/min/1.73 m2, odds ratio [OR] 7.7; 95% confidence interval [CI] 1.7-33.9 vs. OR 4.8; 95% CI 2.7-8.5 vs. OR 3.0; 95% CI 1.5-6.2).

CONCLUSIONS

This study demonstrated that NT-proBNP exhibits different predictive values for prognosis for CAD patients with different levels of renal function. Among the assessed values, the NT-proBNP cut-off value determined using renal function improve the accuracy of the prognosis prediction of CAD. Moreover, lower eGFR is associated with a higher NT-proBNP cut-off value for prognostic prediction.