Human heart-type fatty-acid-binding protein as a point-of-care test in the early diagnosis of acute myocardial infarction

Electroanalytical point-of-care detection of gold standard and emerging cardiac biomarkers for stratification and monitoring in intensive care medicine - a review

Determination of specific cardiac biomarkers (CBs) during the diagnosis and management of adverse cardiovascular events such as acute myocardial infarction (AMI) has become commonplace in emergency department (ED), cardiology and many other ward settings. Cardiac troponins (cTnT and cTnI) and natriuretic peptides (BNP and NT-pro-BNP) are the preferred biomarkers in clinical practice for the diagnostic workup of AMI, acute coronary syndrome (ACS) and other types of myocardial ischaemia and heart failure (HF), while the roles and possible clinical applications of several other potential biomarkers continue to be evaluated and are the subject of several comprehensive reviews. The requirement for rapid, repeated testing of a small number of CBs in ED and cardiology patients has led to the development of point-of-care (PoC) technology to circumvent the need for remote and lengthy testing procedures in the hospital pathology laboratories. Electroanalytical sensing platforms have the potential to meet these requirements. This review aims firstly to reflect on the potential benefits of rapid CB testing in critically ill patients, a very distinct cohort of patients with deranged baseline levels of CBs. We summarise their source and clinical relevance and are the first to report the required analytical ranges for such technology to be of value in this patient cohort. Secondly, we review the current electrochemical approaches, including its sub-variants such as photoelectrochemical and electrochemiluminescence, for the determination  of important CBs highlighting the various strategies used, namely the use of micro- and nanomaterials, to maximise the sensitivities and selectivities of such approaches. Finally, we consider the challenges that must be overcome to allow for the commercialisation of this technology and transition into intensive care medicine.

Components and Pharmacodynamical Mechanism of Yinfupian Based on Liquid Chromatography-Mass Spectrometry and Proteomics Analyses

Objective: According to the treatment records of Yang deficiency syndrome (YDS) with characteristic decoction pieces of lateral root of Aconitum carmichaelii—Yinfupian (YF) in traditional Chinese medicine prepare school, known as “Jianchangbang”. The aim of this study was to investigate differences in the composition and therapeutic mechanism of the unprocessed lateral root of Aconitum carmichaelii (ULRA) and its processed product (YF).

Methods: Ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry and orthogonal partial least squares discriminant analysis method were used to determine and screen the main components of ULRA and YF. Changes in the histological structure and morphology of gonads in rats were observed using hematoxylin-eosin. Enzyme-linked immunosorbent assay was used to determine the contents of serum cyclic adenosine monophosphate and cyclic guanosine monophosphate in YDS rats treated with ULRA and YF. Tandem mass tag proteomics analysis was used to identify the differentially expressed proteins in YDS rats treated with ULRA and YF.

Results: Both ULRA and YF exerted certain therapeutic effects on rats with YDS. They improved the gonadal morphology and increased the contents of serum cyclic adenosine monophosphate and cyclic guanosine monophosphate. After processing of ULRA into YF, the content of C19-diester-diterpenoid alkaloids decreased (converted into C19-monoester-diterpenoid alkaloids and C19-alkylol amine-diterpenoid alkaloids), whereas that of C20-diterpene alkaloids increased. Proteomics analysis showed that cytochrome P450 and aldehyde oxidase 3 (AOX3) were downregulated, whereas cathepsin G (CTSG) was upregulated in rats with YDS. Treatment with ULRA mainly downregulated the expression of α-actinin, fast skeletal troponin, creatine kinase, and myosin. Treatment with YF mainly upregulated the expression of mitochondrial ribosomal protein and mitochondrial inner membrane protein.

Conclusion: ULRA and YF exerted good therapeutic effects on YDS; the main difference in components between these preparations was in C19-diterpenoid alkaloids. ULRA mainly acts on the muscle contraction-related proteins and is closely related to inflammation and myocardial injury. YF mainly acts on the mitochondrial proteins and is closely related to adenosine triphosphate energy metabolism.

Post-Myocardial Infarction Ventricular Remodeling Biomarkers-The Key Link between Pathophysiology and Clinic

Studies in recent years have shown increased interest in developing new methods of evaluation, but also in limiting post infarction ventricular remodeling, hoping to improve ventricular function and the further evolution of the patient. This is the point where biomarkers have proven effective in early detection of remodeling phenomena. There are six main processes that promote the remodeling and each of them has specific biomarkers that can be used in predicting the evolution (myocardial necrosis, neurohormonal activation, inflammatory reaction, hypertrophy and fibrosis, apoptosis, mixed processes). Some of the biomarkers such as creatine kinase-myocardial band (CK-MB), troponin, and N-terminal-pro type B natriuretic peptide (NT-proBNP) were so convincing that they immediately found their place in the post infarction patient evaluation protocol. Others that are related to more complex processes such as inflammatory biomarkers, atheroma plaque destabilization biomarkers, and microRNA are still being studied, but the results so far are promising. This article aims to review the markers used so far, but also the existing data on new markers that could be considered, taking into consideration the most important studies that have been conducted so far.

Early Diagnostic Performance of Heart-Type Fatty Acid Binding Protein in Suspected Acute Myocardial Infarction: Evidence From a Meta-Analysis of Contemporary Studies

BACKGROUND

Although cardiac troponin is the cornerstone in diagnosis of acute myocardial infarction (AMI), the accuracy is still suboptimal in the early hours after chest pain onset. Due to its small size, heart-type fatty acid-binding protein (H-FABP) has been reported accurate in diagnosis of AMI, however, this remains undetermined. The aim is to investigate the diagnostic performance of H-FABP alone and in conjunction with high-sensitivity troponin (hs-Tn) within 6 hours of symptom onset. Furthermore, accuracy in 0h/3h algorithm was also assessed.

METHODS

Medline and EMBASE databases were searched; sensitivity, specificity and area under ROC curve (AUC) were used as measures of the diagnostic accuracy. We pooled data on bivariate modelling, threshold effect and publication bias was applied for heterogeneity analysis.

RESULTS

Twenty-two studies with 6602 populations were included, pooled sensitivity, specificity and AUC of H-FABP were 0.75 (0.68-0.81), 0.81 (0.75-0.86) and 0.85 (0.82-0.88) within 6 hours. Similar sensitivity (0.76, 0.69-0.82), specificity (0.80, 0.71-0.87) and AUC (0.85, 0.82-0.88) of H-FABP were observed in 4185 (63%) patients in 0h/3h algorithm. The additional use of H-FABP improved the sensitivity of hs-Tn alone but worsened its specificity (all p<0.001), and resulted in no improvement of AUC (p>0.99). There was no threshold effect (p=0.18) and publication bias (p=0.31) in this study.

CONCLUSIONS

H-FABP has modest accuracy for early diagnosis of AMI within 3 and 6 hours of symptom onset. The incremental value of H-FABP seemed much smaller and was of uncertain clinical significance in addition to hs-Tn in patients with suspected AMI. Routine use of H-FABP in early presentation does not seem warranted.

A Study on the Role of Heart Type Fatty Acid Binding Protein in the Diagnosis of Acute Myocardial Infarction

INTRODUCTION

Heart type Fatty Acid Binding Protein (H-FABP) has been proposed as an early cardiac biomarker for the diagnosis of acute myocardial Infarction (AMI) using animal models and clinical samples.

AIM

The study aimed to evaluate the role of H-FABP in early detection of AMI by comparing its sensitivity, specificity and predictive value with Creatinine Kinase-MB (CK-MB) and Cardiac Troponin I (cTnI).

MATERIALS AND METHODS

This is a cross-sectional descriptive study of 50 patients admitted with the diagnosis of AMI at a tertiary care hospital in South India. The study group was categorised in to those coming to the hospital within four hours of symptom onset and those coming in between 4 to 12 hours. H-FABP was compared with those of troponin T and myoglobin tests.

RESULTS

Among patients presenting within four hours of symptom onset, the sensitivity of H-FABP was 60% and was significantly higher than that of cardiac Troponin I (cTnI, 18.8%) and Creatinine Kinase (CK)-MB (12.5%). But specificity was only 23.53% and was less than that of cTnI (66.67%) and CK-MB (100%). In patients presenting during 4 to 12 hours of symptom onset, the sensitivity of H-FABP was 86.96% which was comparable to that of cTnI (90.9%) and CK-MB (77.3%). The specificity was 60% in the 4-12 hours group which was comparable to that of cTnI (50%) and CK-MB (50%).

CONCLUSION

The H-FABP is a sensitive biomarker for the diagnosis of AMI in the initial hours after symptom onset when the standard biomarkers may not be elevated, but it is less specific. During 4-12 hours of symptom onset it is as sensitive and specific as standard cardiac biomarkers troponin and CK-MB. Due to these factors H-FABP can be considered as a promising cardiac biomarker which can be used along with troponins and CK-MB at present.

Beyond the Limits: Clinical Utility of Novel Cardiac Biomarkers

Preoperative assessment of cardiovascular risk is essential when it comes to extensive noncardiac surgery procedures. Therefore, accurate and timely diagnosis of myocyte damage is vital. In modern medical practice it is believed that the so-called "multimarker" approach is the most appropriate and most accurate, but new research points out that there are novel biomarkers which could be used independently. Studies that evaluate miRNA, H-FABP, and MR-PAMP give encouraging results. When it comes to miRNA clinical studies show high statistical significance, especially in the case of acute myocardial infarction (P = 0.001). Statistical significance of P = 0.007 was found in acute coronary syndrome, when H-FABP was measured. Biochemical marker MR-PAMP showed statistical significance of P < 0.0001 in most clinical studies.

Diagnostic markers of acute myocardial infarction

Acute myocardial infarction (AMI) is a major cause of morbidity and mortality worldwide. The highest risk of fatality occurs within the initial hours of onset of AMI. Thus, early diagnosis of cardiac ischemia is critical for the effective management of patients with AMI. Improper diagnosis of patients with chest pain often leads to inappropriate admission of patients without AMI and vice versa. In addition to clinical history, physical examination, accurate electrocardiogram findings and assessment of cardiac biomarkers have an important role in the early diagnosis of acute ischemia. The present review discusses in detail the various cardiac biomarkers released during the event of an AMI.

Troponin T and Heart Type Fatty Acid Binding Protein (h-Fabp) as Biomarkers in Patients Presenting with Chest Pain

Acute coronary syndrome (ACS) is a term for a range of clinical signs and symptoms suggestive of myocardial ischemia. It results in functional and structural changes and ultimately releasing protein from injured cardiomyocytes. These cardiac markers play a major role in diagnosis and prognosis of ACS. This study aims to assess the efficacy of heart type fatty acid binding protein (h-FABP) as a marker for ACS along with the routinely used hs-TropT. In our observational study, plasma h-FABP (cut-off 6.32 ng/ml) and routinely done hs-Trop T (cutoff 0.1 and 0.014 ng/ml) were estimated by immunometric laboratory assays in 88 patients with acute chest pain. Based on the clinical and laboratory test findings the patients were grouped into ACS (n = 41) and non-ACS (n = 47). The diagnostic sensitivity, specificity, NPV, PPV and ROC curve at 95 % CI were determined. Sensitivity of hs-TropT (0.1 ng/ml), hs-TropT (0.014 ng/ml) and h-FABP were 53, 86 and 78 % respectively and specificity for the same were 98, 73 and 70 % respectively. Sensitivity, specificity and NPV calculated for a cut-off combination of hs-TropT 0.014 ng/ml and h-FABP was 100, 51 and 100 % respectively. These results were substantiated by ROC analysis. Measurement of plasma h-FABP and hs-TropT together on admission appears to be more precise predictor of ACS rather than either hs-Trop T or h-FABP.

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.

Diabetic patients have increased perioperative cardiac risk in heart-type fatty acid-binding protein-based assessment

OBJECTIVE

To test the potential role of heart-type fatty acid-binding protein (H-FABP) in detecting increased perioperative cardiac risk in comparison with cardiac troponin I (cTnI) in the early postoperative period.

SUBJECTS AND METHODS

Sixty-seven patients who had clinical risk factors and underwent elective intermediate - or high-risk noncardiac surgery were included in this study. Serum specimens were analyzed for H-FABP and cTnI levels before and at 8 h after surgery. None of the patients had chest pain; 27 had a history of ischemic heart disease, 3 of heart failure, 5 of cerebrovascular diseases, 40 of diabetes and 46 of hypertension.

RESULTS

The mean duration of the operations was 2.33 ± 1.27 h (range 1-6). In the postoperative period, 27 (40.3%) patients had increased H-FABP levels (≥7.5 ng/ml); the median preoperative serum H-FABP level was 0.13 ng/ml (<0.1-5.9) and the median postoperative H-FABP level was 6.86 ng/ml (<0.1-13.7). Only 1 (1.5%) patient had cTnI >0.1 µg/l during the postoperative period. Correlation analysis revealed that the presence of diabetes was associated with an increased H-FABP level (r = 0.30, p = 0.01). Of the 27 patients with H-FABP ≥7.5 ng/ml, 21 (87%) had diabetes. There was no significant correlation with other clinical risk factors, type or duration of surgery.

CONCLUSION

The H-FABP levels significantly increased in the postoperative period. Most patients with increased postoperative H-FABP levels were diabetic. High H-FABP levels could alert clinicians to increased perioperative cardiovascular risk and could prevent underdiagnosis, especially in diabetic patients.

High-sensitive troponin T assay for the diagnosis of acute myocardial infarction: an economic evaluation

Background

Delayed diagnosis and treatment of Acute Myocardial Infarction (AMI) has a major adverse impact on prognosis in terms of both morbidity and mortality. Since conventional cardiac Troponin assays have a low sensitivity for diagnosing AMI in the first hours after myocardial necrosis, high-sensitive assays have been developed. The aim of this study was to assess the cost effectiveness of a high-sensitive Troponin T assay (hsTnT), alone or combined with the heart-type fatty acid-binding protein (H-FABP) assay in comparison with the conventional cardiac Troponin (cTnT) assay for the diagnosis of AMI in patients presenting to the hospital with chest pain.

Methods

We performed a cost-utility analysis (quality adjusted life years-QALYs) and a cost effectiveness analysis (life years gained-LYGs) based on a decision analytic model, using a health care perspective in the Dutch context and a life time time-horizon. The robustness of model predictions was explored using one-way and probabilistic sensitivity analyses.

Results

For a life time incremental cost of 30.70 Euros, use of hsTnT over conventional cTnT results in gain of 0.006 Life Years and 0.004 QALY. It should be noted here that hsTnT is a diagnostic intervention which costs only 4.39 Euros/test more than the cTnT test. The ICER generated with the use of hsTnT based diagnostic strategy comparing with the use of a cTnT-based strategy, is 4945 Euros per LYG and 7370 Euros per QALY. The hsTnT strategy has the highest probability of being cost effective at thresholds between 8000 and 20000 Euros per QALY. The combination of hsTnT and h-FABP strategy’s probability of being cost effective remains lower than hsTnT at all willingness to pay thresholds.

Conclusion

Our analysis suggests that hsTnT assay is a very cost effective diagnostic tool relative to conventional TnT assay. Combination of hsTnT and H-FABP does not offer any additional economic and health benefit over hsTnT test alone.

Comparative study of high sensitivity troponin T and heart-type fatty acid-binding protein in STEMI patients

AIM AND BACKGROUND

Heart-type fatty acid-binding proteins (H-FABP) which are detected within 2-3 h of acute myocardial infarction are involved in uptake of free fatty acids in the myocardium. Our aim in the present study is to compare window periods of H-FABP to high sensitivity troponin T (hs-Trop T) in acute ST elevation myocardial infarction (STEMI).

METHODS

160 STEMI diagnosed patient's serum samples are analyzed for hs-Trop T and H-FABP. Different window periods of chest pain onset (<3 h, 3-6 h and >6 h) are compared with complications, in-hospital mortality and statistically analyzed.

RESULTS

From 160 patients, 53 (33%) cases are presented in <3 h, 75 (47%) in 3-6, and 32 (20%) after >6 h respectively. Accordingly sensitivity of hs-Trop T was 92%, 94% and 97% while H-FABP was 75%, 88% and 84%, respectively. Overall sensitivity was 94% and 82% respectively. Statistically significant difference between mean hs-Trop T values with respect to window period <3, 3-6 and >6 h was 0.21, 0.35 and 0.80 ng/ml respectively, p value < 0.0001. No significant difference in H-FABP values was observed. Hs-Trop T positively correlated with age (r = 0.153, P = 0.05), window period (r = 0.363, P < 0.0001), TIMI score (r = 0.208, P = 0.008), ejection fraction (r = 0.191, P = 0.008), serum H-FABP (r = 0.229, P = 0.004), and serum hs-CRP (r = 0.326, p < 0.001). There was a statistically significant difference of mean hs-Trop T values with or without in hospital mortality (0.35 vs. 0.85 ng/ml, respectively, p = 0.008). No significant correlation to age, TIMI score, ejection fraction and hs-CRP values for H-FABP was observed.

CONCLUSION

It appears that hs-Trop T is a more sensitive marker than H-FABP in early hours of AMI and higher hs-Trop T predicts increase in-hospital mortality.

A simple score for rapid risk assessment of non-high-risk pulmonary embolism

OBJECTIVE

We tested whether bedside testing for H-FABP is, alone or integrated in combination models, useful for rapid risk stratification of non-high-risk PE.

METHODS

We prospectively studied 136 normotensive patients with confirmed PE. H-FABP was determined using a qualitative bedside-test showing a positive result for plasma concentration >7 ng/ml.

RESULTS

Overall, 11 patients (8.1 %) had an adverse 30-day outcome. Of 58 patients (42.6 %) with a positive H-FABP bedside-test, 9 (15.5 %) had an unfavourable course compared to 2 of 78 patients (2.6 %) with a negative test result (p = 0.009). Logistic regression analysis indicated a sevenfold increased risk for an adverse outcome (95 % CI, 1.45-33.67; p = 0.016) for patients with a positive H-FABP bedside-test. Additive prognostic information were obtained by a novel score including the H-FABP bedside-test (1.5 points), tachycardia (2 points), and syncope (1.5 points) (OR 11.57 [2.38-56.24]; p = 0.002 for ≥3 points). Increasing points were associated with a continuous exponential increase in the rate of an adverse 30-day outcome (0 % for patients with 0 points and 44.4 % for ≥5 points). Notably, this simple score provided similar prognostic value as the combination of the H-FABP bedside-test with echocardiographic signs of right ventricular dysfunction (OR 12.73 [2.51-64.43]; p = 0.002).

CONCLUSIONS

Bedside testing for H-FABP appears a useful tool for immediate risk stratification of non-high-risk patients with acute PE, who may be at increased risk of an adverse outcome, in particular if integrated in a novel score without the need of echocardiographic examination.

Cardiac biomarkers in the intensive care unit

Cardiac biomarkers (CB) were first developed for assisting the diagnosis of cardiac events, especially acute myocardial infarction. The discoveries of other CB, the better understanding of cardiac disease process and the advancement in detection technology has pushed the applications of CB beyond the 'diagnosis' boundary. Not only the measurements of CB are more sensitive, the applications have now covered staging of cardiac disease, timing of cardiac events and prognostication. Further, CB have made their way to the intensive care setting where their uses are not just confined to cardiac related areas. With the better understanding of the CB properties, CB can now help detecting various acute processes such as pulmonary embolism, sepsis-related myocardial depression, acute heart failure, renal failure and acute lung injury. This article discusses the properties and the uses of common CB, with special reference to the intensive care setting. The potential utility of "multimarkers" approach and microRNA as the future CB are also briefly discussed.

Cardiac biomarkers in acute myocardial infarction

Each year, a large number of patients are seen in the Emergency Department with presentations necessitating investigation for possible acute myocardial infarction. Patients can be stratified by symptoms, risk factors and electrocardiogram results but cardiac biomarkers also have a prime role both diagnostically and prognostically. This review summarizes both the history of cardiac biomarkers as well as currently available (established and novel) assays. Cardiac troponin, our current "gold standard" biomarker criterion for the diagnosis of myocardial infarction has high sensitivity and specificity for this diagnosis and therapies instituted in patients with elevated troponin have been shown to influence outcomes. Other markers of myocardial necrosis, inflammation and neurohormonal activity have also been shown to have either diagnostic or prognostic utility, but none have been shown to be superior to troponin. The measurement of multiple biomarkers and the use of point of care markers may accelerate current diagnostic protocols for the assessment of such patients.

Novel biomarkers in diagnosing cardiac ischemia in the emergency department: a systematic review

BACKGROUND

Novel biomarkers of myocardial ischemia and inflammatory processes have the potential to improve diagnostic accuracy of acute coronary syndrome (ACS) within a shorter time interval after symptom onset.

OBJECTIVE

The objective was to review the recent literature and evaluate the evidence for use of novel biomarkers in diagnosing ACS in patients presenting with chest pain or symptoms suggestive of cardiac ischemia to the emergency department or chest pain unit.

METHODS

A literature search was performed in MEDLINE, EMBASE, Cochrane DSR, ACP Journal Club, DARE, CCTR, CMR, HTA, and NHSEED for studies from 2004 to 2010. We used the inclusion criteria: (1) human subjects, (2) peer-reviewed articles, (3) enrolled patients with ACS, acute myocardial infarction or undifferentiated signs and symptoms suggestive of ACS, and (4) English language or translated manuscripts. Two reviewers conducted a hierarchical selection and assessment using a scale developed by the International Liaison Committee on Resuscitation.

RESULTS

Out of a total 3194 citations, 58 articles evaluating 37 novel biomarkers were included for final review. Forty-one studies did not support the use of their respective biomarkers. Seventeen studies supported the use of 5 biomarkers, particularly when combined with cardiac-specific troponin: heart fatty acid-binding protein, ischemia-modified albumin, B-type natriuretic peptide, copeptin, and matrix metalloproteinase-9.

CONCLUSION

In patients presenting to the emergency department with chest pain or symptoms suggestive of cardiac ischemia, there is inadequate evidence to suggest the routine testing of novel biomarkers in isolation. However, several novel biomarkers have the potential to improve the sensitivity of diagnosing ACS when combined with cardiac-specific troponin.

Heart fatty acid-binding protein in combination with the 80-lead body surface potential map improves early detection of acute myocardial infarction in patients who are cardiac troponin T-negative at presentation

Of patients who present with ischemic-type chest pain and a negative cardiac troponin T (cTnT) at first medical contact, there are patients at a very early stage of infarction. The aim of this research was to assess heart fatty acid-binding protein (H-FABP), a novel marker of myocyte necrosis, in combination with the 80-lead body surface potential map (BSPM) in the early diagnosis of acute myocardial infarction (AMI).

METHODS

In this prospective study, consecutive patients presenting with acute ischemic-type chest pain between 2003 and 2006 were enrolled. At first medical contact, blood was sampled for cTnT and H-FABP; in addition, a 12-lead electrocardiogram (ECG) and BSPM were recorded. A second cTnT was sampled 12 hours or more after presentation. Peak cTnT 0.03 μg/L or higher diagnosed AMI. Elevated H-FABP was 5 ng/mL or higher. A cardiologist blinded to both the clinical details and 12-lead ECG interpreted the BSPM.

RESULTS

Enrolled were 407 patients (age 62 ± 13 years; 70% men). Of these 407, 180 had cTnT less than 0.03 μg/L at presentation. Acute myocardial infarction occurred in 52 (29%) of 180 patients. Of these 180 patients, 27 had ST-segment elevation (STE) on ECG, 104 had STE on BSPM (sensitivity, 88%; specificity, 55%), and 95 (53%) had H-FABP elevation. The proportion with elevated H-FABP was higher in the AMI group compared with non-AMI group (P < .001). Body surface potential map STE was significantly associated with H-FABP elevation (P < .001). Of those with initial cTnT less than 0.03 μg/L, the c-statistic for the receiver operating characteristic curve distinguishing AMI from non-AMI using H-FABP alone was 0.644 (95% confidence interval [CI], 0.521-0.771), using BSPM alone was 0.716 (95% CI, 0.638-0.793), and using the combination of BSPM and H-FABP was 0.812 (95% CI, 0.747-0.876; P < .001).

CONCLUSION

In patients with acute ischemic-type chest pain who have a normal cTnT at presentation, the combination of H-FABP and BSPM at first assessment identifies those with early AMI (c-statistic, 0.812; P < .001), thus allowing earlier triage to reperfusion therapy and secondary prevention.

Heart-type fatty acid binding protein as an adjunct to cardiac troponin-I for the diagnosis of myocardial infarction

We hypothesized that when used in combination with cardiac troponins, heart-type fatty acid binding protein (H-FABP) would have greater diagnostic value than conventional markers for the early diagnosis of myocardial infarction (MI). Patients with typical chest pain at a single emergency department were consecutively enrolled. Initial blood samples were drawn for H-FABP, myoglobin, creatine kinase isoenzyme MB (CK-MB), and cardiac troponin-I (cTnI) measurements. MI was defined by serial cTnI measurements. To evaluate the adjunctive role of biochemical markers, we derived and compared logistic regression models predicting MI in terms of their discrimination (area under the receiver operating characteristics curve, AUC) and overall fit (Bayesian information criterion, BIC). Seventy-six of 170 patients were diagnosed as having MI. The AUC of cTnI, H-FABP, myoglobin, and CK-MB were 0.863, 0.827, 0.784, and 0.772, respectively. A logistic regression model using cTnI (P = 0.001) and H-FABP (P < 0.001) had the biggest AUC (0.900) and the best fit determined by BIC. Sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of this model at 30% probability were 81.6%, 80.9%, 4.26, and 0.23, respectively. H-FABP has a better diagnostic value than both myoglobin and CK-MB as an adjunct to cTnI for the early diagnosis of MI.

Heart fatty acid binding protein (H-FABP) as a diagnostic biomarker in patients with acute coronary syndrome

AIMS AND OBJECTIVES

Diagnosis of myocardial ischaemia at an early stage in the emergency department is often difficult. A recently proposed biomarker, heart fatty acid binding protein (H-FABP) has been found to appear in the circulation superior to that of cardiac troponins in the early hours of acute coronary syndrome. We proposed to evaluate the levels of H-FABP and ascertain its utility as an early biomarker for acute coronary syndrome (ACS).

METHODS AND RESULTS

The present study was carried out in 485 subjects, of whom 297 were diagnosed as patients with ACS, 89 were diagnosed as non-cardiac chest pain (NCCP) and 99 people served as healthy controls. H-FABP levels were measured in comparison with standard markers such as troponin I and CK-MB in all subjects enrolled in the study. The levels of H-FABP were significantly raised in patients when compared to controls and NCCP (P<0.001). Receiver Operator Characteristic Curve (ROC) analysis showed H-FABP to be a good discriminator between patients with ischaemic heart disease and patients without ischaemic heart disease. The area under the curve was found to be 0.965 with 95% CI (0.945-0.979). The cut-off value above which H-FABP can be considered positive was found to be 17.7ng/ml.

CONCLUSION

H-FABP is a promising biomarker for the early detection of patients with acute coronary syndrome.

Heart-type fatty acid binding protein is an independent predictor of death and ventricular dysfunction after coronary artery bypass graft surgery

BACKGROUND

Heart-type fatty acid binding protein (hFABP) functions as a myocardial fatty acid transporter and is released into the circulation early after myocardial injury. We hypothesized that hFABP is superior to conventional cardiac biomarkers for predicting early perioperative myocardial injury after coronary artery bypass graft (CABG) surgery.

METHODS

A prospective cohort study of 1298 patients undergoing primary CABG with cardiopulmonary bypass (CPB) was performed at 2 institutions. Four plasma myocardial injury biomarkers (hFABP; cardiac troponin I [cTnI]; creatine kinase, MB [CK-MB] fraction; and myoglobin) were measured at 7 perioperative time points. The association among perioperative cardiac biomarkers and ventricular dysfunction, hospital length of stay (HLOS), and up to 5-year postoperative mortality (median 3.3 years) was assessed using Cox proportional hazard models. We defined in-hospital ventricular dysfunction as a new requirement for 2 or more inotropes, or new placement of an intraaortic balloon pump, or ventricular assist device either during the intraoperative period after the patient separated from CPB or postoperatively in the intensive care unit.

RESULTS

The positive and negative predictive values of mortality for hFABP are 13% (95% confidence interval [CI], 9%-19%) and 95% (95% CI, 94%-96%), respectively, which is higher than for cTnI and CK-MB. After adjusting for clinical predictors, both postoperative day (POD) 1 and peak hFABP levels were independent predictors of ventricular dysfunction (P < 0.0001), HLOS (P < 0.05), and 5-year mortality (P < 0.0001) after CABG surgery. Furthermore, POD1 and peak hFABP levels were significantly superior to other evaluated biomarkers for predicting mortality. In a repeated-measures analysis, hFABP outperformed all other models of fit for HLOS. Patients with POD2 hFABP levels higher than post-CPB hFABP levels had an increased mortality compared with those patients whose POD2 hFABP levels decreased from their post-CPB level (hazard ratio, 10.9; 95% CI, 5.0-23.7; P = 7.2 × 10(-10)). Mortality in the 120 patients (10%) with a later hFABP peak was 18.3%, compared with 4.7% in those who did not peak later. Alternatively, for cTnI or CK-MB, no difference in mortality was detected.

CONCLUSION

Compared with traditional markers of myocardial injury after CABG surgery, hFABP peaks earlier and is a superior independent predictor of postoperative mortality and ventricular dysfunction.

Biomarkers in pulmonary arterial hypertension

Despite recent advances in medical treatment, pulmonary arterial hypertension (PAH) continues to be associated with high morbidity and mortality. While the diagnosis is established via a right heart catheterisation, current non-invasive measures of disease severity and response to treatment used in clinical practice are the 6-min walk distance and the World Health Organization functional class. Although both parameters correlate with disease severity and prognosis, they have significant limitations. A major shortcoming in assessing PAH is lack of standardised, non-invasive, objective parameters that function as biomarkers to help assess the severity and prognosis of disease and to follow patients' response to treatment. In this article, we will review current knowledge on potential biomarkers associated with diagnosis, prognosis and response to treatment of PAH. Most biomarkers are either being evaluated for potential use in clinical practice, or being used as research tools.

Comparison of usefulness of heart-type fatty acid binding protein versus cardiac troponin T for diagnosis of acute myocardial infarction

We aimed to assess the additive diagnostic value of measuring the serum levels of soluble human heart-type fatty acid binding protein (H-FABP) in the early diagnosis of acute myocardial infarction (AMI) in unselected patients with chest pain. A total of 97 consecutive patients with acute ischemic-type chest pain were prospectively enrolled and classified according to the American Heart Association/American College of Cardiology guidelines. The test characteristics of H-FABP and cardiac troponin T serum levels at admission revealed a greater sensitivity of H-FABP in the first 4 hours of symptoms (86% vs 42%, p <0.05). Combining H-FABP and cardiac troponin T also improved the sensitivity in the detection of AMI (97% vs 71%, p <0.05) but demonstrated a greater misclassification rate (25% vs 9%, p <0.05). The specificity of H-FABP was poor (65%, 95% confidence interval 58% to 71%). Receiver operating characteristics revealed a poor performance of H-FABP in patients with non-ST-elevation myocardial infarction. Classification tree analysis demonstrated that an H-FABP-related improvement in the early definite rule-out of AMI (reduction of false-negative rate from 11% to 3%) was at the expense of an increase in the false-positive rate to 5%. In conclusion, measurement of H-FABP, in addition to cardiac troponin T, serum levels within the first 4 hours of symptoms improves the sensitivity and negative predictive value for the detection of AMI at the cost of test accuracy and precision, especially in patients with non-ST-elevation myocardial infarction.

Prognostic value of combination of heart-type fatty acid-binding protein and ischemia-modified albumin in patients with acute coronary syndromes and normal troponin T values

Recent studies have suggested that heart-type fatty acid-binding protein (H-FABP) may detect ongoing myocardial damage involved in the progression of acute coronary syndromes (ACS). This study was prospectively designed to examine whether the combination of H-FABP, a marker for ongoing myocardial damage, and ischemia-modified albumin (IMA), a marker for myocardial ischemia, would effectively diagnose patients with ACS. H-FABP values above 1.5 microg/l can be correctly measured via an ELISA and 6 microg/l is the currently used cut-off value (1-3). We measured serum H-FABP and IMA of 108 patients on admission within 12 hr after onset of chest pain and normal troponin T. serum samples from ACS group (n=82) had decreased capacity of ACB [64 (61-67) U/ml] compared with non-ACS ischemic chest pain group (n=26) samples [75 (71-78) U/ml] (P<0.05). The combination of IMA and H-FABP usually had better sensitivity [96.3% (92.2-100%)] (P<0.05) and accuracy [92.6 (87.7-97.5%)] (P<0.05) than when individually used. Thus, the combination of H-FABP and IMA measurements after initiation of chest pain may be highly effective for risk stratification in patients with ACS and normal cardiac troponin T.

Heart-type fatty acid-binding protein is a useful marker for organ dysfunction and leptin alleviates sepsis-induced organ injuries by restraining its tissue levels

Heart-type fatty acid-binding protein (H-FABP) is widely distributed and has been used to diagnose certain diseases. However, its alteration during infection-evoked organ dysfunction, and the potential association between leptin and it in injury or infection has not been investigated. In the current study, serum H-FABP, leptin, C-reactive protein and interleukin-1beta in the patients with pulmonary infection-induced multiple organ dysfunction were detected. Moreover, a mouse model of sepsis was established, and serum alanine transaminase, uric acid, tissue H-FABP, myeloperoxidase, superoxide dismutase activity and histological alterations in lung and intestine were investigated. Serum H-FABP and leptin increased simultaneously and significantly in the patients, and leptin alleviated pulmonary and intestinal injuries by restraining tissue H-FABP secretions in the mouse model of sepsis. Other investigated variables showed different but independent alterations. In conclusion, H-FABP represents a useful diagnostic marker for organ dysfunction, and its association with leptin will be a novel target for emergency aid.

The role of heart-type fatty acid-binding protein in the diagnosis of acute coronary syndrome

BACKGROUND

Heart-type fatty acid-binding protein (H-FABP) is a membrane-bound protein that facilitates transport of fatty acids from the blood into the heart. It is currently being used outside the United States for the early diagnosis of myocardial infarction (MI). However, previous studies have shown inconsistent correlation of H-FABP with standard cardiac biomarkers.

METHODS

Fifty patients admitted with ST segment elevation MI (n=25), non-ST segment elevation MI (n=15) or unstable angina (n=10) were evaluated. The CardioDetect med cardiac infarction test (rennesens GmbH, Germany) was used to measure both qualitative and quantitative H-FABP.

RESULTS

Of the 40 patients with acute MI, the initial troponin assay was positive in 35 patients (88%), the qualitative H-FABP assay was positive in 23 patients (58%) and the quantitative H-FABP assay was positive in 15 patients (38%) (P=0.001). No patient with MI had a positive H-FABP assay with a negative initial troponin assay.

CONCLUSION

In the present study, the results of both the qualitative and quantitative H-FABP assays neither appeared earlier nor provided increased sensitivity compared with troponin in diagnosing acute MI. Accordingly, the use of H-FABP as a diagnostic tool for MI is limited.

The value of biochemical markers for risk stratification prior to hospital admission in acute chest pain

We describe the use of biochemical markers in the pre-hospital setting with regard to diagnostic accuracy for the detection of an acute myocardial infarction (AMI) and for prognosis in connection with acute chest pain. The sensitivity has been reported to be limited; blood sampling occurs very early and often prior to the release of biochemical markers into the circulation. The specificity was in some studies also limited, but this is more difficult to explain. New biochemical markers like human heart fatty acid binding protein (H-FACB) have shown improved diagnostic accuracy, in the pre-hospital setting, in one small pilot study compared with traditional biochemical markers like troponins, creatine kinase (CK-MB) and myoglobin. However, in a recent small study, the sensitivity for troponin I (when a low decision limit for myocardial damage was used), when analysed prior to hospital admission, was reported to be very high. The latter data need to be confirmed in larger studies and various biochemical markers reflecting various pathophysiological aspects of the disease need to be tested before the analysis of any marker can be recommended for use in the pre-hospital setting of a suspected AMI.

Heart-type Fatty acid-binding protein in Acute Myocardial infarction Evaluation (FAME): background and design of a diagnostic study in primary care

BACKGROUND

Currently used biomarkers for cardiac ischemia are elevated in blood plasma after a delay of several hours and therefore unable to detect acute coronary syndrome (ACS) in a very early stage. General practitioners (GPs), however, are often confronted with patients suspected of ACS within hours after onset of complaints. This ongoing study aims to evaluate the added diagnostic value beyond clinical assessment for a rapid bedside test for heart-type fatty-acid binding protein (H-FABP), a biomarker that is detectable as soon as one hour after onset of ischemia.

METHODS

Participating GPs perform a blinded H-FABP rapid bedside test (Cardiodetect) in patients with symptoms suggestive of ACS such as chest pain or discomfort at rest. All patients, whether referred to hospital or not, undergo electrocardiography (ECG) and venapunction for a plasma troponin test within 12-36 hours after onset of complaints. A final diagnosis will be established by an expert panel consisting of two cardiologists and one general practitioner (blinded to the H-FABP test result), using all available patient information, also including signs and symptoms. The added diagnostic value of the H-FABP test beyond history taking and physical examination will be determined with receiver operating characteristic curves derived from multivariate regression analysis.

CONCLUSION

Reasons for presenting the design of our study include the prevention of publication bias and unacknowledged alterations in the study aim, design or data-analysis. To our knowledge this study is the first to assess the diagnostic value of H-FABP outside a hospital-setting. Several previous hospital-based studies showed the potential value of H-FABP in diagnosing ACS. Up to now however it is unclear whether these results are equally promising when the test is used in primary care. The first results are expected in the end of 2008.