Release kinetics of early ischaemic biomarkers in a clinical model of acute myocardial infarction

Soluble Flt-1 in AMI Patients Serum Inhibits Angiogenesis of Endothelial Progenitor Cells by Suppressing Akt and Erk’s Activity

Simple Summary

Acute myocardial infarction (AMI) is the leading cause of mortality in the world. Endothelial progenitor cells (EPCs) exert important roles in the recovery of collateral circulation via angiogenesis. In this study, we studied the characteristics of EPCs isolated from the peripheral blood of AMI patients and healthy subjects. We found that the number of EPCs increased in AMI patients and exhibited faster migration compared to healthy subjects. However, no difference in angiogenic activity was observed in EPCs between AMI patients and healthy subjects. Interestingly, the serum level of sFlt-1 was elevated in AMI patients. Further analysis demonstrated that sFlt-1 inhibited EPCs angiogenesis in vitro by inhibiting the Akt and Erk signaling pathways. In conclusion, our study uncovered that EPCs increased in quantity, but their angiogenesis activity was inhibited by serum sFlt-1 in AMI patients.

Abstract

In acute myocardial infarction (AMI), endothelial progenitor cells (EPCs) are essential for the recovery of collateral circulation via angiogenesis. Clinical research has shown that the poor prognosis of the patients with AMI is closely associated with the cell quantity and function of EPCs. Whether there are differences in the biological features of EPCs from AMI patients and healthy subjects is worth exploring. In this study, EPCs were isolated from human peripheral blood and identified as late-stage EPCs by flow cytometry, immunofluorescence, and blood vessel formation assay. Compared to healthy subjects, AMI patients had more EPCs in the peripheral blood compared to healthy subjects. In addition, EPCs from AMI patients exhibited higher migration ability in the transwell assay compared to EPCs from healthy subjects. However, no difference in the angiogenesis of EPCs was observed between AMI patients and healthy subjects. Further studies revealed that soluble vascular endothelial growth factor receptor 1 (sFlt-1) in the serum of AMI patients was involved in the inhibition of EPCs angiogenesis by suppressing the Akt and Erk pathways. In conclusion, this study demonstrated that elevated serum sFlt-1 inhibits angiogenesis of EPC in AMI patients. Our findings uncover a pathogenic role of sFlt-1 in AMI.

Cardiovascular Biomarkers: Lessons of the Past and Prospects for the Future

Cardiovascular diseases (CVDs) are a major healthcare burden on the population worldwide. Early detection of this disease is important in prevention and treatment to minimise morbidity and mortality. Biomarkers are a critical tool to either diagnose, screen, or provide prognostic information for pathological conditions. This review discusses the historical cardiac biomarkers used to detect these conditions, discussing their application and their limitations. Identification of new biomarkers have since replaced these and are now in use in routine clinical practice, but still do not detect all disease. Future cardiac biomarkers are showing promise in early studies, but further studies are required to show their value in improving detection of CVD above the current biomarkers. Additionally, the analytical platforms that would allow them to be adopted in healthcare are yet to be established. There is also the need to identify whether these biomarkers can be used for diagnostic, prognostic, or screening purposes, which will impact their implementation in routine clinical practice.

Promising Novel Biomarkers in Cardiovascular Diseases

Cardiovascular diseases remain the most common causes of death globally, according to the World Health Organization. In recent years, a great number of biomarkers have been investigated, whereas only some have gained value in the diagnosis, prognosis, and risk stratification of different cardiovascular illnesses. As numerous studies have investigated the diagnostic yield of novel biomarkers in various disease entities every year, this review aims to provide an overview of the current status of four promising representatives. In particular, this manuscript refers to soluble suppression of tumorigenicity 2 (sST2), heart-type fatty acid binding protein (H-FABP), growth differentiation factor (GDF-15) and soluble urokinase-type plasminogen activator receptor (suPAR). These markers are of special interest as they are thought to provide an accurate estimate of cardiovascular risk in certain patient populations, especially those with pre-existing diseases, such as obesity or diabetes mellitus. We sought to give an overview of their function, individual diagnostic and predictive value and determination in the laboratory. A review of the literature regarding the aforementioned cardiovascular biomarkers yielded manifold results with respect to their individual diagnostic and prognostic value. Yet, the clinical relevance of these findings remains unclear, warranting further studies to identify their optimal use in clinical routine.

Association of myocardial hemorrhage and persistent microvascular obstruction with circulating inflammatory biomarkers in STEMI patients

INTRODUCTION

Myocardial hemorrhage (IMH) and persistent microvascular obstruction (MVO) are associated with impaired myocardial recovery and adverse clinical outcomes in STEMI patients. However, their relationship with circulating inflammatory biomarkers is unclear in human patients.

METHODS AND RESULTS

Twenty consecutive patients referred for primary percutaneous coronary intervention of first STEMI were included in a prospective study. Blood sampling was performed at admission, 4, 12, 24, 48 hours, 7 and 30 days after reperfusion for inflammatory biomarker (C reactive protein, fibrinogen, interleukin-6 (IL-6) and neutrophils count) assessment. At seven days, cardiovascular magnetic resonance (CMR) was performed for infarct size, MVO and IMH assessment. Median infarct size was 24.6% Interquartile range (IQR) [12.0-43.5] of LV mass and edema was 13.2% IQR [7.7-36.1] of LV mass. IL-6 reached a peak at H24 (5.6 pg/mL interquartile range (IQR) [2.5-17.5]), CRP at H48 (11.7 mg/L IQR [7.1-69.2]), fibrinogen one week after admission (4.4 g/L IQR [3.8-6.7]) and neutrophils at H12 (9.0 G/L IQR [6.5-12.7]). MVO was present in 11 patients (55% of the study population) and hemorrhage in 7 patients (35%). Patients with IMH had significantly higher IL-6, CRP, fibrinogen, and neutrophils levels compared to patients without IMH. Patients with persistent MVO had significantly higher CRP, fibrinogen and neutrophils level compared to patients without MVO, but identical IL-6 kinetics.

CONCLUSION

In human patients with acute myocardial infarction, intramyocardial hemorrhage appears to have a stronger relationship with inflammatory biomarker release compared to persistent MVO. Attenuating myocardial hemorrhage may be a novel target in future adjunctive STEMI treatments.

[The elderly patient with acute coronary syndrome]

The elderly patient with acute coronary syndrome (ACS) is often not treated on an evidence based basis due to age, previous illnesses and also an increased risk of bleeding. This applies to both drug and interventional therapy. However, valid data clearly show that elderly patients in particular benefit from guideline-adherent therapy, especially interventional revascularisation.

Heart-type fatty acid binding protein predicts cardiovascular events in patients with stable coronary artery disease: a prospective cohort study

Background

Heart-type fatty acid binding protein (H-FABP) has been reported to be a prognostic predictor for cardiovascular outcome in acute coronary syndrome (ACS). However, its prognostic utility in patients with stable coronary artery disease (CAD) has not been well established. The aim of this study was to assess the association between H-FABP with the severity of coronary disease and cardiovascular events (CVEs) in patients with stable CAD.

Methods

A total of 4,370 angiography-proven CAD patients were consecutively enrolled. The severity of CAD was assessed by Gensini Score (GS) and the numbers of diseased vessels. The CVEs included cardiovascular death, myocardial infarction, stroke and coronary revascularization. Cox regression analysis with adjusted hazard ratios (HRs) and Kaplan-Meier analysis were used to evaluate the relation of H-FABP to CVEs in this cohort.

Results

During a median follow-up of 51 months, 353 CVEs occurred. Overall, patients in the highest levels of H-FABP group had increased rate of multi-vessel stenosis and higher GS compared with those in the lowest group (P<0.05, respectively). Moreover, H-FABP levels were significantly higher in patients with events compared to those without (P<0.001). In Cox regression analysis, elevated H-FABP levels were found to be independently associated with a high risk of CVEs [adjusted HRs: 1.453; 95% confidence intervals (CIs): 1.040–2.029, P=0.028], especially with cardiovascular death (adjusted HRs: 2.865; 95% CI: 1.315–6.243, P=0.008).

Conclusions

Our results demonstrated that H-FABP was also a useful predictor for CVEs in patients with stable CAD, which needed to be verified by further studies.

Evaluation of the cardioprotective effects of crystalloid del Nido cardioplegia solution via a rapid and accurate cardiac marker: heart-type fatty acid-binding protein

Background/aim

Our aim in this study was to compare the efficacy and safety of crystalloid del Nido solution and cold blood cardioplegia solution on clinical and laboratory parameters.

Materials and methods

Sixty patients who underwent elective coronary bypass operation between July 2019 and January 2020 were included in our study. Patients were divided into 2 groups of 30 patients using del Nido solution (DNS) and cold blood cardioplegia solution (CBCS), which were given for cardiac arrest. Demographic data, preoperative, postoperative 0th h, 6th h and 4th day creatine kinase myocardial band (CK-MB) and troponin I values were compared with a specific cardiac enzyme heart-type fatty acid-binding protein (H-FABP).

Results

We found that aortic cross clamp duration and cardiopulmonary bypass (CPB) time were shorter in patients using del Nido solution than cold blood cardioplegia solution (57.30 ± 23.57 min, 76.07 ± 27.18 min, P = 0.006) (95.07 ± 23.06 min, 114.13 ± 33.93, P = 0.014). Total cardioplegia solution volume was higher in the cold blood cardioplegia solution group (1426.67 ± 416.00 vs. 1200 ± 310.73 P = 0.02). Preoperative and postoperative levels of cardiac enzymes including CK-MB, troponin I and H-FABP were comparable in del Nido solution and cold blood cardioplegia solution groups.

Conclusion

According to these results, when we compare both demographic data and CK-MB, troponin I and H-FABP levels, both cardioplegia solutions were comparable regarding safety and efficacy in terms of myocardial protection.

Heart-Type Fatty Acid-Binding Protein (H-FABP) and its Role as a Biomarker in Heart Failure: What Do We Know So Far?

BACKGROUND

Heart failure (HF) remains one of the leading causes of death to date despite extensive research funding. Various studies are conducted every year in an attempt to improve diagnostic accuracy and therapy monitoring. The small cytoplasmic heart-type fatty acid-binding protein (H-FABP) has been studied in a variety of disease entities. Here, we provide a review of the available literature on H-FABP and its possible applications in HF. Methods: Literature research using PubMed Central was conducted. To select possible studies for inclusion, the authors screened all available studies by title and, if suitable, by abstract. Relevant manuscripts were read in full text.

RESULTS

In total, 23 studies regarding H-FABP in HF were included in this review.

CONCLUSION

While, algorithms already exist in the area of risk stratification for acute pulmonary embolism, there is still no consensus for the routine use of H-FABP in daily clinical practice in HF. At present, the strongest evidence exists for risk evaluation of adverse cardiac events. Other future applications of H-FABP may include early detection of ischemia, worsening of renal failure, and long-term treatment planning.

Relationship Between Level of Heart Type Fatty Acid Binding Protein (Before and after Procedures) with Acute Renal Failure after PCI in Patients Under PCI

BACKGROUND & OBJECTIVE

Acute renal failure (AKI) is one of the most important complications of PCI. Due to delay in creatinine increase, we need specific factors to detect AKI earlier. The aim of this study is to evaluate the valuable factors by focusing on HFAB-P that can be predictive for AKI after Percutaneous Coronary Intervention (PCI).

METHODS

This prospective study was performed on 95 patients (55 males and 44 females aged between 49-78 years) under PCI in Golestan and Imam Khomeini hospitals in Ahvaz. Patients were divided into three groups based on the development of AKI after the procedure: no AKI, severe AKI (doubling of serum creatinine or needing dialysis) and any type of AKI (increased creatinine ≥ 0/3 mg/dl or a 50% increase in the means of 1/5 times serum creatinine). The demographic and clinical characteristics of the patients, the medical history and the results of the HFABP marker, GFR, and creatinine before and after PCI were evaluated for all patients.

RESULTS

The progenies showed 6 patients with severe AKI, 17 patients with any type of AKI, and 72 patients without AKI. Diabetes (P = 0.003), hypertension (P = 0.027), gender of patients (P = 0.025) and hospital admission days (P <0.001) were significantly different among the groups. Patients' age and positive troponin were significantly higher in patients with AKI. HFABP was the only factor that had significant changes before and after PCI (P <0.001). The cut-off value of HFABP was 4.69 with 95.6% sensitivity and 84.7% specificity. It has a good negative predictive value of 98.39% which suggests it to be a good test for the AKI prediction. Glomerular Filtration Rate (GFR) and creatinine (Cr) were significantly different after PCI (P <0.001).

CONCLUSION

HFABP can be considered as a predictor for AKI after PCI. Moreover, our study suggests that evaluating several parameters such as Cr and GFR before and after PCI can predict the AKI development after PCI.

The prognostic significance of heart-type fatty acid binding protein in patients with stable coronary heart disease

To investigate the prognostic value of heart-type fatty acid binding protein (H-FABP) in patients with stable coronary heart disease (SCHD). A total of 1,071 patients with SCHD were prospectively enrolled in this Taiwan multicenter registry study, followed for 24 months. The cut-off value of H-FABP, 4.143 ng/mL, was determined using receiver operating characteristic curves. The primary cardiovascular (CV) outcome was composite CV events, defined as cardiovascular or cerebrovascular death, myocardial infarction (MI), stroke, angina related-hospitalization, PAOD-related hospitalization and heart failure. Secondary outcomes included CV or cerebrovascular death, nonfatal MI, nonfatal stroke, and acute heart failure-related hospitalization. We found that the high H-FABP group had more than a two-fold higher rate of primary CV outcomes than the low H-FABP group (32.36% vs. 15.78%, p < 0.001). Eleven patients (4.82%) of the high H-FABP group died during the 24 months of follow-up, compared to only one patient (0.12%) in the low H-FABP group. The acute heart failure-related hospitalization rate was also significantly higher in the high H-FABP group (3.5% vs. 0.95%, p < 0.005). The results remained significant after adjusting for baseline covariates. In conclusion, H-FABP was an independent predictor for CV outcomes in the patients with SCHD, mainly in CV death and acute heart failure-related hospitalization.

Early kinetics of serum Interleukine-17A and infarct size in patients with reperfused acute ST-elevated myocardial infarction

BACKGROUND

Recently, it was shown that interleukin-17A (IL-17A) is involved in the pathophysiology of reperfusion injury and associated with infarct size (IS) in experimental models of myocardial infarction. Our aim was to evaluate whether the IL-17A serum level and the IL-17A active fraction was correlated with IS in humans.

METHODS

101 patients presenting with a ST-elevated Myocardial Infarction (STEMI) referred for primary percutaneous coronary intervention (PPCI) and 10 healthy controls were included. For each participant, blood samples at admission (H0) and 4 hours after admission (H4) were collected. IL-17A serum levels were assessed using ELISA and the active fraction was assessed with a functional test. IS was determined by peak troponin and peak CK levels for every patient and by contrast-enhanced cardiac magnetic resonance (ce-CMR) for 20 patients.

RESULTS

The IL-17A serum level was significantly increased in STEMI patients compared to healthy controls, (0.9 pg/mL IQR [0.0-3.2] at H0 and 1.0 pg/mL IQR [0.2-2.8] at H4 versus 0.2 pg/mL IQR [0.0-0.7] for healthy controls; p<0.005). At either time points, IL-17A levels did not correlate with IS as measured by peak troponin, peak CK pr ce-CMR. Also, no correlation was found between the active fraction of IL-17A and IS.

CONCLUSION

Serum IL-17A level is significantly increased in patients at the early phase of acute MI compared to healthy controls. However, the level of IL-17A in the early hours after reperfusion does not correlate with IS.

Heart-type fatty acid-binding protein in cardiovascular disease: A systemic review

Fatty acid-binding proteins, whose clinical applications have been studied, are a family of proteins that reflect tissue injury. Heart-type fatty acid-binding protein (H-FABP) is a marker of ongoing myocardial damage and useful for early diagnosis of acute myocardial infarction (AMI). In the past decade, compared to other cardiac enzymes, H-FABP has shown more promise as an early detection marker for AMI. However, the role of H-FABP is being re-examined due to recent refinement in the search for newer biomarkers, and greater understanding of the role of high-sensitivity troponin. We discuss the current role of H-FABP as an early marker for AMI in the era of high sensitive troponin. H-FABP is highlighted as a prognostic marker for a broad spectrum of fatal diseases, viz., AMI, heart failure, arrhythmia, and pulmonary embolism that could be associated with poor clinical outcomes. Because the cut-off value of what constitutes an abnormal H-FABP potentially differs for each cardiovascular event and depends on the clinical setting, an optimal cut-off value has not been clearly established. Of note, several factors such as age, gender, and cardiovascular risk factors, which affect H-FABP levels need to be considered in this context. In this review, we discuss the clinical applications of H-FABP as a prognostic marker in various clinical settings.

Heart-type fatty acid binding protein is a sensitive biomarker for early AMI detection in troponin negative patients: a pilot study

BACKGROUND

Early detecting AMI in individuals presenting to the ED with chest pain continues to be a challenge. cTn is the gold standard for AMI diagnosis but early presenters (<1 hours from symptom onset) maybe cTn negative on admission. We analysed the diagnostic value of h-FABP and hs-TnI in patients presenting to ED with chest pain and no cTnI elevations.

METHODS

28 AMI and 28 no-AMI individuals both presented to ED within one hour from pain onset were included. Blood donors were analysed for h-FABP cut-off identification. Among AMI patients, 55% were positive for h-FABP and 34.6% were positive for hs-TnI (p = .015), thus 21% were positive only for h-FABP. The diagnostic accuracy was assessed by ROC curve. h-FABP showed a higher sensitivity but lower specificity than hs-TnI.

CONCLUSIONS

In our study, the frequency of h-FABP positivity among AMI patients was higher than that of hs-TnI, which would have missed six of them; however, hs-TnI AUC was superior to that of h-FABP. These preliminary findings might confirm that h-FABP may be a good candidate for AMI rule-in/rule-out within the ED context.

Heart-Type Fatty Acid Binding Protein and Ischemia-Modified Albumin for Detection of Myocardial Infarction After Coronary Artery Bypass Graft Surgery

BACKGROUND

Heart-type fatty acid binding protein (hFABP) and ischemia-modified albumin (IMA) have been put forward as novel biomarkers to detect myocardial injury shortly after onset of ischemia. We compared hFABP and IMA with cardiac troponin I (cTnI) for speed and reliability in the diagnosis of perioperative myocardial infarction (PMI) after coronary artery bypass graft surgery (CABG).

METHODS

In all, 210 consecutive patients undergoing isolated CABG with cardiopulmonary bypass were enrolled in a prospective study. Blood samples were taken perioperatively and throughout the first 72 hours after surgery; clinical data and events were recorded. In cohort A, serum concentrations of hFABP and cTnI were measured using a combined quantitative bedside assay. In cohort B, IMA and cTnI serum concentrations were measured using an albumin cobalt binding test. Perioperative myocardial infarction was defined using a cTnI cutoff of greater than 10.5 ng/mL occurring within 24 hours of CABG or new electrocardiographic changes.

RESULTS

In cohort A, 14 patients were identified with PMI (group 1), whereas 94 had no PMI and served as controls (group 2). Both hFABP and cTnI were increased in group 1 as compared with group 2 (p < 0.001). Although cTnI did not differ before 12 hours, hFABP diverged much earlier, at 1 hour postoperatively (p < 0.001). An hFABP concentration of 20 μg/mL at 1 hour detected PMI with an area under the curve of 77.1%. In cohort B, 18 patients were identified with PMI (group 3), and 84 patients served as controls (group 4). No difference in cTnI values could be observed between the groups until 12 hours postoperatively. Ischemia-modified albumin failed to differentiate at any postoperative time point; the low discriminative power of IMA was confirmed with an area under the curve of 53.3% at 1 hour, 48.5% at 6 hours, and 39.3% at 12 hours postoperatively.

CONCLUSIONS

Heart-type fatty acid binding protein is a sensitive and rapid biomarker that detected PMI reliably at 1 hour after CABG, much earlier than cTnI. The diagnostic value of IMA for detection of PMI appears to be very limited in this setting.

Improved risk stratification of patients with acute coronary syndromes using a combination of hsTnT, NT-proBNP and hsCRP with the GRACE score

Background:

Clinical scores and biomarkers improve risk stratification of patients with acute coronary syndromes. However, little is known about their value in patients referred for coronary angiography.

Methods:

Consecutive patients admitted at four Swiss university hospitals with a diagnosis of acute coronary syndrome were enrolled into the SPUM-ACS Biomarker Cohort between 2009 and 2012. Patients were followed at 30 days and 1 year with assessment of adjudicated events including all-cause mortality and the composite of all-cause mortality or non-fatal recurrent myocardial infarction.

Results:

Events and biomarkers were analysed in 1892 patients (52.4% with ST-segment elevation myocardial infarction, 43.3% with non-ST-segment elevation myocardial infarction and 4.3% with unstable angina). Death at 30 days occurred in 35 patients (1.9%) and at 1 year in 80 patients (4.3%). The choice of troponin assay (conventional versus high sensitivity) to calculate the Global Registry of Acute Coronary Events (GRACE) score did not affect risk prediction. The prognostic accuracy of the GRACE score was improved when combined with three individual biomarkers including high sensitivity troponin T (hsTnT), N-terminal-pro B-type natriuretic peptide (NT-proBNP) and high sensitivity C-reactive protein (hsCRP) to yield a 9% increment (C-statistic 0.73–>0.82) for the discrimination of short-term risk for all-cause mortality. In contrast, the novel biomarkers placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1) and the ratio sFlt-1/PlGF did not improve risk stratification.

Conclusions:

In patients with acute coronary syndrome referred for coronary angiography, combinations of biomarkers including hsTnT, NT-proBNP and hsCRP with the GRACE score enhanced risk discrimination.

Clinical Trials Registration:

NCT01000701

High-sensitivity troponin and novel biomarkers for the early diagnosis of non-ST-segment elevation myocardial infarction in patients with atrial fibrillation

AIMS

To evaluate the diagnostic performance of high-sensitivity troponin I (hsTnI) and other novel biomarkers for diagnosing non-ST-segment elevation myocardial infarction (NSTEMI) in patients with atrial fibrillation.

METHODS

In an acute chest pain cohort (N=1673), mean age 61.4±13.6 (34% female), we measured hsTnI and 13 established and novel biomarkers reflecting ischaemia, necrosis, inflammation, myocardial stress, angiogenesis on admission and after three hours in order to investigate their diagnostic accuracy for NSTEMI.

RESULTS

In atrial fibrillation patients (N=299) hsTnI on admission had the best discriminatory ability for NSTEMI (area under the curve 0.97) with only two novel biomarkers, copeptin and heart-type fatty acid binding protein, having area under the curve >0.70. Measured biomarkers showed comparable discriminatory ability in atrial fibrillation and non-atrial fibrillation patients. The combination of hsTnI on admission with additional biomarkers did not clinically significantly improve diagnostic performance. In atrial fibrillation patients, hsTnI concentrations ⩽21.7 ng/L (99th percentile in a healthy German cohort) on admission gave a negative predictive value of ~100% (95% confidence interval 97-100%). The combination of hsTnI on admission and absolute change of hsTnI concentration after three hours of ⩾40 ng/L resulted in a positive predictive value of 81.2% and sensitivity of 88.6%. Diagnostic accuracy was validated in an independent cohort (N=1076).

CONCLUSION

The diagnostic accuracy of hsTnI in patients with acute chest pain and atrial fibrillation is high and comparable to those without atrial fibrillation. Absolute change in hsTnI concentration enhanced diagnostic performance. No clinically relevant improvement was achieved by adding other biomarkers.

Myocardial injury associated with transcatheter aortic valve implantation (TAVI)

Transcatheter aortic valve implantation (TAVI) has emerged as an important treatment option for elderly patients with symptomatic aortic stenosis whose risk is too high or prohibitive for conventional surgery. Despite notable progress during the past decade, continuous efforts directed at further improvement of procedural safety and performance are required, especially considering expanding indications for interventional treatment options among lower-risk populations. One issue that needs to be addressed is myocardial damage, which can frequently be observed after TAVI and has been linked to worse prognosis. Yet, knowledge concerning the underlying mechanisms and clinical impact remains scarce, and further investigation in this field is warranted. In this review, we provide a contemporary summary of the types of myocardial injury associated with TAVI, including access-related injury, mechanical trauma and ischemia, the role of myocardial biomarkers, and the impact on left ventricular function, with emphasis on potential mechanisms and clinical implications.

Reference Values and Release Kinetics of B-Type Natriuretic Peptide Signal Peptide in Patients with Acute Myocardial Infarction

BACKGROUND

The signal peptide for human B-type natriuretic peptide preprohormone (BNPsp), which is released from cardiomyocytes, is increased in plasma of patients with acute myocardial infarction (AMI); however, its exact release kinetics have not been defined.

METHODS

We measured BNPsp and high-sensitivity cardiac troponin T (hs-cTnT) in a reference group of individuals without structural heart disease (n = 285) and determined the release kinetics of these biomarkers in patients (n = 29) with hypertrophic obstructive cardiomyopathy undergoing transcoronary ablation of septal hypertrophy (TASH), a procedure allowing exact timing of onset of iatrogenic AMI. Blood samples were collected before TASH and at numerous preselected time points after TASH.

RESULTS

The reference median BNPsp concentration was 53.4 pmol/L [interquartile range (IQR) 47.0–61.0; 95th percentile 85.9 pmol/L; 99th percentile 116.3 pmol/L]. Baseline concentrations in patients undergoing TASH were higher than in the reference group [91.9 pmol/L (IQR 62.9–116.4); P &lt; 0.0001]. BNPsp increased significantly, peaking at 15 min after induction of AMI [149.6 pmol/L (109.5–204.9) vs baseline; P = 0.004] and declining slowly thereafter, falling below the preprocedural value after 8 h (P = 0.014). hs-cTnT increased significantly 15 min after induction of AMI [26 ng/L (19–39) vs 18 ng/L (11–29); P = 0.001] and remained high at all later time points.

CONCLUSIONS

BNPsp concentrations increased immediately after AMI induction, providing early evidence of myocardial injury. The release kinetics of BNPsp differed from those of hs-cTnT. These findings provide information that should help in establishing the diagnostic value of BNPsp in the setting of early AMI.

Perioperative heart-type fatty acid binding protein is associated with acute kidney injury after cardiac surgery

Acute Kidney Injury (AKI) is a common complication after cardiac surgery and is associated with worse outcomes. Since heart fatty acid binding protein (H-FABP) is a myocardial protein that detects cardiac injury, we sought to determine if plasma H-FABP was associated with AKI in the TRIBE-AKI cohort; a multi-center cohort of 1219 patients at high risk for AKI who underwent cardiac surgery. The primary outcomes of interest were any AKI (Acute Kidney Injury Network (AKIN) stage 1 or higher) and severe AKI (AKIN stage 2 or higher). The secondary outcome was long-term mortality after discharge. Patients who developed AKI had higher levels of H-FABP pre- and post-operatively than patients who did not have AKI. In analyses adjusted for known AKI risk factors, first post-operative log(H-FABP) was associated with severe AKI (adjusted OR 5.39 [95% CI, 2.87-10.11] per unit increase), while pre-operative log(H-FABP) was associated with any AKI (2.07 [1.48-2.89]) and mortality (1.67 [1.17-2.37]). These relationships persisted after adjustment for change in serum creatinine (for first postoperative log(H-FABP)) and biomarkers of cardiac and kidney injury, including brain natriuretic peptide, cardiac troponin-I, interleukin-18, liver fatty acid binding protein, kidney injury molecule-1, and neutrophil gelatinase associated lipocalin. Thus, peri-operative plasma H-FABP levels may be used for risk-stratification of AKI and mortality following cardiac surgery.

Incremental value of heart-type fatty acid-binding protein in suspected acute myocardial infarction early after symptom onset

BACKGROUND

The early diagnosis of acute myocardial infarction (AMI) very soon after symptom onset remains a major clinical challenge, even when using high-sensitivity cardiac troponin (hs-cTnT).

METHODS AND RESULTS

We investigated the incremental value of heart-type fatty acid-binding protein (hFABP) in a pre-specified subgroup analysis of patients presenting with suspected AMI within 1 h of symptom onset to the emergency department (ED) in a multicentre study. HFABP was measured in a blinded fashion. Two independent cardiologists using all available clinical information, including hs-cTnT, adjudicated the final diagnosis. Overall, 1411 patients were enrolled, of whom 105 patients presented within 1 h of symptom onset. Of these, 34 patients (32.4%) had AMI. The diagnostic accuracy as quantified by the area under the receiver-operating characteristics curve (AUC) of hFABP was high (0.84 (95% CI 0.74-0.94)). However, the additional use of hFABP only marginally increased the diagnostic accuracy of hs-cTnT (AUC 0.88 (95% CI 0.81-0.94) for hs-cTnT alone to 0.90 (95% CI 0.83-0.98) for the combination; p=ns). After the exclusion of 18 AMI patients with ST-segment elevation, similar results were obtained. Among the 16 AMI patients without ST-segment elevation, six had normal hs-cTnT at presentation. Of these, hFABP was elevated in two (33.3%) patients.

CONCLUSIONS

hFABP does not seem to significantly improve the early diagnostic accuracy of hs-cTnT in the important subgroup of patients with suspected AMI presenting to the ED very early after symptom onset.

Point-of-care heart-type fatty acid binding protein versus high-sensitivity troponin T testing in emergency patients at high risk for acute coronary syndrome

BACKGROUND

High-sensitivity cardiac troponin testing is used to detect myocardial damage in patients with acute chest pain. Heart-type fatty acid binding protein (H-FABP) may be an alternative, available as point-of-care test.

METHODS

Patients (n=203) referred by general practitioners for suspected acute coronary syndrome or presenting with typical chest pain and one major cardiovascular risk factor at the emergency department were prospectively included in a single-centre cohort study. High-sensitivity cardiac troponin T (hs-TnT) and point-of-care H-FABP testing were concomitantly performed at admission and after 6h.

RESULTS

Maximal hs-TnT levels above the 99th percentile were observed in 152 patients (75%) with 127 (63%) fulfilling criteria for myocardial infarction. Upon admission, hs-TnT and H-FABP were associated with an area under the curve (95% CI) of 0.83 (0.77-0.89) and 0.79 (0.73-0.85), respectively, to predict myocardial infarction, which increased to 0.93 (0.90-0.97) and 0.88 (0.84-0.93), respectively, after 6h. The diagnostic accuracy for non-ST-segment elevation myocardial infarction was somewhat lower with an area under the curve (95% CI) of 0.80 (0.72-0.87), 0.90 (0.84-0.96), 0.73 (0.64-0.81) and 0.77 (0.67-0.86), respectively. When assessment was performed within 3h of chest pain onset, diagnostic accuracy of H-FABP versus hs-TnT was similar. Each standard deviation increase in admission H-FABP was associated with a 68% relative risk increase of all-cause mortality (p-value=0.027) during 666 ± 155 days of follow-up.

CONCLUSIONS

Point-of-care H-FABP testing has lower diagnostic accuracy compared with hs-TnT assessment in patients with high pre-test acute coronary syndrome probability, but might be of interest when assessment is possible early after chest pain onset.