Value of cardiac biomarker measurement in the differential diagnosis of infiltrative cardiomyopathy patients with preserved left ventricular systolic function

Serum alpha 1 antitrypsin potent act as an early diagnostic biomarker for cardiac amyloidosis

Cardiac amyloidosis is a refractory cardiomyopathy with a poor prognosis and lacks effective treatments. N-terminal pro-brain natriuretic peptide (NT-proBNP) and troponin T are poor prognostic factors for myocardial amyloidosis. However, NT-proBNP and troponin also serve as markers of heart failure and myocardial infarction, lacking specificity. Whether abnormal elevation of alpha-1 antitrypsin in myocardial amyloidosis also predicts the poor prognosis of patients remains unknown. We conducted a retrospective single-center case-control study to analyze the serological and physical examination data of 83 cardiac amyloidosis patients and 68 healthy controls matched by gender and age. We aimed to explore the onset and prognostic factors of cardiac amyloidosis. The serum alpha-1 antitrypsin level (169.78 ± 39.59 mg/dl) in patients with cardiac amyloidosis was significantly higher than that in the normal control (125.92 ± 18.26 mg/dl). Logistic regression results showed that alpha-1 antitrypsin, free sialic acid, high-density lipoprotein cholesterol, apolipoprotein A/B ratio, and homocysteine were predictors of cardiac amyloidosis. Multivariable logistic regression showed that only alpha 1 antitrypsin was an independent risk factor for cardiac amyloidosis. Receiver operating characteristic curve analysis based on the Mayo stage and troponin level showed the cut-off value of 140.55 mg/dl for alpha-1 antitrypsin in predicting cardiac amyloidosis with 81.7% sensitivity and 83.9% specificity. Elevated alpha-1 antitrypsin levels may be an early diagnostic biomarker for cardiac amyloidosis.

Cardiac Troponin in Patients With Light Chain and Transthyretin Cardiac Amyloidosis: JACC: CardioOncology State-of-the-Art Review

Cardiac amyloidosis (CA) is an infiltrative disease caused by amyloid fibril deposition in the myocardium; the 2 forms that most frequently involve the heart are amyloid light chain (AL) and amyloid transthyretin (ATTR) amyloidosis. Cardiac troponin (cTn) is the biomarker of choice for the detection of myocardial injury and is frequently found to be elevated in patients with CA, particularly with high-sensitivity assays. Multiple mechanisms of myocardial injury in CA have been proposed, including cytotoxic effect of amyloid precursors, interstitial amyloid fibril infiltration, coronary microvascular dysfunction, amyloid- and non-amyloid-related coronary artery disease, diastolic dysfunction, and heart failure. Regardless of the mechanisms, cTn values have relevant prognostic (and potentially diagnostic) implications in both AL and ATTR amyloidosis. In this review, the authors discuss the significant aspects of cTn biology and measurement methods, potential mechanisms of myocardial injury in CA, and the clinical application of cTn in the management of both AL and ATTR amyloidosis.

Layer-specific strain in patients with cardiac amyloidosis using tissue tracking MR

Background

Cardiac infiltration is the major predictor of poor prognosis in patients with systemic amyloidosis, thus it becomes of great importance to evaluate cardiac involvement.

Purpose

We aimed to evaluate left ventricular myocardial deformation alteration in patients with cardiac amyloidosis (CA) using layer-specific tissue tracking MR.

Material and Methods

Thirty-nine patients with CA were enrolled. Thirty-nine normal controls were also recruited. Layer-specific tissue tracking analysis was done based on cine MR images.

Results

Compared with the control group, a significant reduction in LV whole layer strain values (GLS, GCS, and GRS) and layer-specific strain values was found in patients with CA (all P < 0.01). In addition, GRS and GLS, as well as subendocardial and subepicardial GLS, GRS, and GCS, were all diminished in patients with CA and reduced LVEF, when compared to those with preserved or mid-range LVEF (all P < 0.05). GCS showed the largest AUC (0.9952, P = 0.0001) with a sensitivity of 93.1% and specificity of 90% to predict reduced LVEF (<40%). Moreover, GCS was the only independent predictor of LV systolic dysfunction (Odds Ratio: 3.30, 95% CI:1.341-8.12, and P = 0.009).

Conclusion

Layer-specific tissue tracking MR could be a useful method to assess left ventricular myocardial deformation in patients with CA.

Invasive and Non-Invasive Diagnostic Pathways in the Diagnosis of Cardiac Amyloidosis

The appropriate diagnosis and subtyping of cardiac amyloidosis (CA) is frequently missed or delayed due to its vague presentation, clinical overlapping, and diagnostic pitfalls. Recent developments in both invasive and non-invasive diagnostic techniques have significantly changed the diagnostic approach of CA. With the present review, we aim to summarize the current diagnostic approach of CA and to underline the indications of tissue biopsy, either surrogate site or myocardial. The most important factor for timely diagnosis is increased clinical suspicion, especially in certain clinical scenarios. Appropriate imaging with echocardiography or cardiac magnetic resonance (CMR) can provide significant evidence for the diagnosis of CA. Importantly, all patients should undergo monoclonal proteins assessment, with these results significantly determining the steps to follow. A negative monoclonal protein assessment will lead to a non-invasive algorithm which, in combination with positive cardiac scintigraphy, can establish the diagnosis of ATTR-CA. The latter is the only clinical scenario in which the diagnosis can be established without the need of biopsy. However, if the imaging results are negative but the clinical suspicion remains high, a myocardial biopsy should be performed. In the case of the presence of monoclonal protein, an invasive algorithm follows, first by surrogate site sampling and then by myocardial biopsy if the results are inconclusive or prompt diagnosis is needed. The role of endomyocardial biopsy, even though limited by current advances in other techniques, is highly valuable in selected patients and is the only method to reliably establish a diagnosis in challenging cases.

Use of biomarkers to diagnose and manage cardiac amyloidosis

Amyloidoses are characterized by the tissue accumulation of misfolded proteins into insoluble fibrils. The two most common types of systemic amyloidosis result from the deposition of immunoglobulin light chains (AL) and wild-type or variant transthyretin (ATTRwt/ATTRv). Cardiac involvement is the main determinant of outcome in both AL and ATTR, and cardiac amyloidosis (CA) is increasingly recognized as a cause of heart failure. In CA, circulating biomarkers are important diagnostic tools, allow to refine risk stratification at baseline and during follow-up, help to tailor the therapeutic strategy and monitor the response to treatment. Among amyloid precursors, free light chains are established biomarkers in AL amyloidosis, while the plasma transthyretin assay is currently being investigated as a tool for supporting the diagnosis of ATTRv amyloidosis, predicting outcome and monitor response to novel tetramer stabilizers or small interfering RNA drugs in ATTR CA. Natriuretic peptides (NPs) and troponins are consistently elevated in patients with AL and ATTR CA. Plasma NPs, troponins and free light chains hold prognostic significance in AL amyloidosis, and are evaluated for therapy decision-making and follow-up, while the value of NPs and troponins in ATTR is less well established. Biomarkers can be usefully integrated with clinical and imaging variables at all levels of the clinical algorithm of systemic amyloidosis, from screening to diagnosis and prognosis, and treatment tailoring.

Keys to early diagnosis of cardiac amyloidosis: red flags from clinical, laboratory and imaging findings

Cardiac involvement in systemic amyloidosis, due either to immunoglobulin light-chain or transthyretin amyloidosis, influences clinical presentation and is a strong predictor of unfavourable outcome. Until recently considered as a rare, incurable disease, cardiac amyloidosis, is still mis/underdiagnosed, although treatments effective in improving patient survival are now available for both subtypes, including chemotherapy regimens for immunoglobulin light-chain amyloidosis and tetramer stabiliser for transthyretin amyloidosis. Achieving a timely diagnosis allows initiating life-saving therapies and requires the early recognition of clinical, laboratory and imaging signs of cardiac involvement, some of them may be apparent well before the disease becomes clinically manifest. Given the systemic nature of amyloidosis, a close interaction among experts in multiple specialties is also required, including cardiologists, nephrologists, haematologists, neurologists, radiologists, nuclear medicine specialists and internists. As an increased awareness about disease presentation is required to ameliorate diagnostic performance, we aim to provide the clinician with a guide to the screening and early diagnosis of cardiac amyloidosis, and to review the clinical, biohumoral and instrumental ‘red flags’ that should raise the suspicion of cardiac amyloidosis.

A Proteomics-Based Analysis Reveals Predictive Biological Patterns in Fabry Disease

Background: Fabry disease (FD) is an X-linked progressive lysosomal disease (LD) due to glycosphingolipid metabolism impairment. Currently, plasmatic globotriaosylsphingosine (LysoGb3) is used for disease diagnosis and monitoring. However, this biomarker is inconstantly increased in mild forms and in some female patients. Materials and Methods: We applied a targeted proteomic approach to explore disease-related biological patterns that might explain the disease pathophysiology. Forty proteins, involved mainly in inflammatory and angiogenesis processes, were assessed in 69 plasma samples retrieved from the French Fabry cohort (FFABRY) and from 83 healthy subjects. For predictive performance assessment, we also included other LD samples (Gaucher, Pompe and Niemann Pick C). Results: The study yielded four discriminant proteins that include three angiogenesis proteins (fibroblast growth factor 2 (FGF2), vascular endothelial growth factor A (VEGFA), vascular endothelial growth factor C (VEGFC)) and one cytokine interleukin 7 (IL-7). A clear elevation of FGF2 and IL-7 concentrations was observed in FD compared to other LD samples. No correlation was observed between these proteins and globotriaosylsphingosine (LysoGb3). A significant correlation exists between IL-7 and residual enzyme activity in a non-classical phenotype. This highlights the orthogonal biological information yielded by these proteins that might help in stratifying Fabry patients. Conclusion: This work highlights the potential of using proteomics approaches in exploring FD and enhancing FD diagnosis and therapeutic monitoring performances.