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

Fatty-Acid-Binding Proteins: From Lipid Transporters to Disease Biomarkers

Fatty-acid-binding proteins (FABPs) serve a crucial role in the metabolism and transport of fatty acids and other hydrophobic ligands as an intracellular protein family. They are also recognized as a critical mediator in the inflammatory and ischemic pathways. FABPs are found in a wide range of tissues and organs, allowing them to contribute to various disease/injury developments that have not been widely discussed. We have collected and analyzed research journals that have investigated the role of FABPs in various diseases. Through this review, we discuss the findings on the potential of FABPs as biomarkers for various diseases in different tissues and organs, looking at their expression levels and their roles in related diseases according to available literature data. FABPs have been reported to show significantly increased expression levels in various tissues and organs associated with metabolic and inflammatory diseases. Therefore, FABPs are a promising novel biomarker that needs further development to optimize disease diagnosis and prognosis methods along with previously discovered markers.

Evaluation of Dual Marker Approach Using Heart-Type Fatty Acid Binding Protein and High Sensitivity Troponin-I as an Alternative to Serial Sampling for Diagnosis of Acute Myocardial Infarction

Objective

An early rule in (high specificity and high PPV) and early rule out (high sensitivity and high NPV) is essential for diagnosing acute myocardial infarction (AMI) to provide better utilization of resources, cost-effectiveness, and to reduce mortality.

Methods

Consecutive chest pain patients (n=80) with symptoms indicative of coronary artery disease reported to the emergency room within 6 hours after onset of symptoms. An alternate Dual Marker Approach (DMA; both Heart-type Fatty Acid Binding Protein (H-FABP) and High sensitive Troponin-I (hsTnI) at 0 h) was compared to the Double Sampling approach (DSA; hsTnI at 0 h and 3 h (ESC guidelines)).

Results

If both biomarkers were increased (n=17; 77.5%: 11 STEMI and 6 NSTEMI) above their respective cut-off value (HFABP 6.3 ng/mL and hsTnI 20.24 ng/L) at presentation, AMI ensued (100% PPV). Also, if both the markers were below their respective cut-offs at presentation, AMI was safely ruled out (n=41; with only 1 false negative). However, among the patients with either of these markers above their respective cut-off at presentation (n=22), DSA was required to find remaining AMI cases (n=4). Overall, DMA stands best for rule out (sensitivity 95.5%, NPV 97.6%) while DSA is superior for rule in (98.2% specificity, 95.2% PPV).

Conclusion

With the use of the proposed DMA, 58/80 (72.5%) patients with acute chest pain were reliably ruled in/ruled out for AMI at the presentation itself, while the remaining patients still required serial monitoring (DSA) for confirmation.

High-sensitivity troponin assays for early rule-out of acute myocardial infarction in people with acute chest pain: a systematic review and economic evaluation

BACKGROUND

Early diagnosis of acute myocardial infarction is important, but only 20% of emergency admissions for chest pain will actually have an acute myocardial infarction. High-sensitivity cardiac troponin assays may allow rapid rule out of myocardial infarction and avoid unnecessary hospital admissions.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of high-sensitivity cardiac troponin assays for the management of adults presenting with acute chest pain, in particular for the early rule-out of acute myocardial infarction.

METHODS

Sixteen databases were searched up to September 2019. Review methods followed published guidelines. Studies were assessed for quality using appropriate risk-of-bias tools. The bivariate model was used to estimate summary sensitivity and specificity for meta-analyses involving four or more studies; otherwise, random-effects logistic regression was used. The health economic analysis considered the long-term costs and quality-adjusted life-years associated with different troponin testing methods. The de novo model consisted of a decision tree and a state-transition cohort model. A lifetime time horizon (of 60 years) was used.

RESULTS

Thirty-seven studies (123 publications) were included in the review. The high-sensitivity cardiac troponin test strategies evaluated are defined by the combination of four factors (i.e. assay, number and timing of tests, and threshold concentration), resulting in a large number of possible combinations. Clinical opinion indicated a minimum clinically acceptable sensitivity of 97%. When considering single test strategies, only those using a threshold at or near to the limit of detection for the assay, in a sample taken at presentation, met the minimum clinically acceptable sensitivity criterion. The majority of the multiple test strategies that met this criterion comprised an initial rule-out step, based on high-sensitivity cardiac troponin levels in a sample taken on presentation and a minimum symptom duration, and a second stage for patients not meeting the initial rule-out criteria, based on presentation levels of high-sensitivity cardiac troponin and absolute change after 1, 2 or 3 hours. Two large cluster randomised controlled trials found that implementation of an early rule-out pathway for myocardial infarction reduced length of stay and rate of hospital admission without increasing cardiac events. In the base-case analysis, standard troponin testing was both the most effective and the most costly. Other testing strategies with a sensitivity of 100% (subject to uncertainty) were almost equally effective, resulting in the same life-year and quality-adjusted life-year gain at up to four decimal places. Comparisons based on the next best alternative showed that for willingness-to-pay values below £8455 per quality-adjusted life-year, the Access High Sensitivity Troponin I (Beckman Coulter, Brea, CA, USA) [(symptoms > 3 hours AND < 4 ng/l at 0 hours) OR (< 5 ng/l AND Δ < 5 ng/l at 0 to 2 hours)] would be cost-effective. For thresholds between £8455 and £20,190 per quality-adjusted life-year, the Elecsys® Troponin-T high sensitive (Roche, Basel, Switzerland) (< 12 ng/l at 0 hours AND Δ < 3 ng/l at 0 to 1 hours) would be cost-effective. For a threshold > £20,190 per quality-adjusted life-year, the Dimension Vista® High-Sensitivity Troponin I (Siemens Healthcare, Erlangen, Germany) (< 5 ng/l at 0 hours AND Δ < 2 ng/l at 0 to 1 hours) would be cost-effective.

CONCLUSIONS

High-sensitivity cardiac troponin testing may be cost-effective compared with standard troponin testing.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42019154716.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Evidence Synthesis programme and will be published in full in Health Technology Assessment; Vol. 25, No. 33. See the NIHR Journals Library website for further project information.