Cardiac amyloidosis: the need for early diagnosis

Cardiac Amyloidosis: A Narrative Review of Diagnostic Advances and Emerging Therapies

Background/Objectives: Cardiac amyloidosis (CA) is an underdiagnosed and potentially life-threatening infiltrative cardiomyopathy characterized by the extracellular deposition of misfolded amyloid fibrils in cardiac tissue. It is most commonly associated with light-chain (AL) amyloidosis and transthyretin (ATTR) amyloidosis, either hereditary or wild-type. The disease often presents with non-specific symptoms, leading to delayed diagnosis and treatment. This study aims to provide a comprehensive overview of the pathophysiology, diagnostic strategies, and current therapeutic approaches for cardiac amyloidosis, with a focus on improving early detection and clinical outcomes. Methods: A narrative review was conducted using databases such as PubMed and Scopus, covering the period from September 2016 to March 2025. Keywords such as "cardiac amyloidosis", "cardiac amyloidosis from transthyretin", "cardiomyopathy", "transthyretin", "immunoglobulin light-chain amyloidosis", and "familial amyloidosis" were used. Relevant clinical trials and guideline-based management recommendations were also included. Results: This review highlights that non-invasive imaging modalities and serum biomarker analyses are key to reducing diagnostic delays. New therapeutic developments, including gene-editing technologies and RNA-based therapies, show promise in early trials. Multidisciplinary management and increased awareness are crucial for timely diagnosis and treatment optimization. Conclusions: The early recognition of cardiac amyloidosis remains a major clinical challenge. Advances in non-invasive diagnostics and emerging disease-modifying therapies are transforming the prognosis of affected patients. Continued research and heightened clinical suspicion are essential to improve outcomes in this complex and heterogeneous disease.

Myocardium From Patients With ATTR Amyloidosis Produces Less Force Secondary to Increased Fibrosis

Amyloid transthyretin cardiac amyloidosis is one of the most common infiltrative cardiomyopathies. Contractile, biochemical, and histological assays were performed on myocardium from patients with and without amyloid transthyretin amyloidosis. Force was reduced in amyloidosis, but calcium sensitivity was increased. The change in calcium sensitivity may reflect dephosphorylation of troponin I. The proportion of stiffness attributable to the extracellular matrix was larger in amyloidosis. Septal fibrosis and amyloid burden correlated with measurements from LV samples. Technetium pyrophosphate scans may detect increased microcalcifications in amyloidosis myocardium. Replacement of myocytes with extracellular matrix is the most important factor depressing contractile force in amyloidosis myocardium.

Long-Term Clinical Outcomes in Patients With Transthyretin Cardiac Amyloidosis Versus Non-Ischemic Cardiomyopathy

Background

We sought to compare the long-term outcomes in patients with transthyretin cardiac amyloidosis (CA) compared to those with non-ischemic cardiomyopathy (NICM) from a large healthcare system database.

Methods

Patients with CA or NICM were identified from SSM Healthcare System's data warehouse using ICD codes. Inclusion criteria included at least 6 months of follow-up. Outcomes studied were heart failure hospitalization (HFH), ventricular tachyarrhythmias (VTA), implantable cardiac defibrillator (ICD) and pacemaker (PM) placement. Multivariate logistic analysis and Kaplan-Meier survival curves were constructed.

Results

We identified 231 patients with CA and 462 with NICM, matched for age, race, and gender. CA patients had higher incidence of peripheral vascular disease (48.5% vs. 35.5%) and coronary artery disease (10.4% vs. 6.1%). Mean follow-up was 48.1 ± 33.1 months. CA patients had a higher rate of HFH (57.6% vs. 46.1%) and a lower rate of ICD (1.7% vs. 5.9%). In the multivariate model, CA patients had significantly higher odds for HFH (odds ratio: 1.86; 95% confidence interval: 1.29 - 2.68). Kaplan-Meier survival curves showed a trend toward earlier HFH and later PM or ICD implantation in CA patients.

Conclusions

In this retrospective study from a large healthcare system database, compared to NICM, transthyretin CA patients had significantly higher rates of HFH, similar odds of VTA, and a lower likelihood of receiving an intracardiac device.

Advances and challenges in echocardiographic diagnosis and management of cardiac amyloidosis

Cardiac amyloidosis is an infiltrative cardiomyopathy characterized by the abnormal accumulation of amyloid proteins within the heart muscle. It is recognized as a rare yet significant cardiac disease that is often overlooked as a potential cause of heart failure and cardiac arrhythmias, particularly in older individuals with rates escalating from 8 to 17 cases per 100,000 individuals. Cardiac amyloidosis primarily manifests as two predominant subtypes: light-chain and transthyretin amyloidosis, collectively accounting for over 95% of clinical cases. Early diagnosis of these conditions is often hindered by overlapping symptoms with other cardiac pathologies, resulting in diagnostic delays and suboptimal patient outcomes. Echocardiography, a non-invasive imaging technique, has become indispensable for diagnosing cardiac amyloidosis, uncovering crucial echocardiographic signs such as thickening of the left ventricular wall, diastolic dysfunction, and a granular appearance of the myocardium. Recent advancements in echocardiography have significantly enhanced the diagnostic accuracy of cardiac amyloidosis and improved patient management. Advanced echocardiographic techniques, including strain imaging, 3D echocardiography, and contrast echocardiography, have significantly enhanced diagnostic accuracy and prognostication. Future directions in echocardiography encompass the integration of artificial intelligence, the development of novel contrast agents, and the refinement of 4D echocardiography to further optimize patient care. This study explores the pivotal role of echocardiography in both diagnosing and managing cardiac amyloidosis, delving into the disease's underlying mechanisms, distinctive imaging characteristics, the significance of regular echocardiographic assessments, and discusses the challenges associated with differentiating between various types of amyloidosis without supplemental imaging or biopsy methods.

Demographic and regional trends in systemic and cardiovascular amyloidosis-related mortality among older adults in the United States from 1999 to 2020

Despite therapy advancements, amyloidosis mortality rates for older adults (aged ≥ 65) are rising. This study analyzes trends in amyloidosis-related mortality among older adults in the U.S. We conducted a cross-sectional analysis of death certificates from the CDC WONDER database for amyloidosis-related deaths from 1999 to 2020. Age-adjusted mortality rates (AAMRs) per 100,000 persons and annual percent change (APC) were calculated by age, race/ethnicity, urban-rural classification, and region. From 1999 to 2020, AAMR for amyloidosis in older adults (aged ≥ 65) in the U.S. increased from 2.7 to 5.6. Men consistently had higher AAMRs than women (men: 3.7 vs. women: 2.2 in 1999; men: 8.5 vs. women: 3.5 in 2020). In 2020, Non-Hispanic Blacks had the highest AAMR at 11.8, with an APC of 19.8 (95% CI 10.5-25.5). Regional differences were notable, with AAMRs highest in the Northeast (6.9) and lowest in the South (4.2). Large metropolitan areas had a higher AAMR (6.3) than non-metropolitan areas (4.6). Cardiac amyloidosis accounted for 68.8% of deaths, with AAMR rising from 1.7 to 4.2. There has been a significant increase in AAMRs for amyloidosis in the U.S. from 1999 to 2020, particularly among males, Non-Hispanic Blacks, and those in large metropolitan and Northeast areas. These findings stress the need for enhanced prevention and treatment strategies for older adults.

Diagnostic Utility of Relative Apical Sparing Index in Cardiac Amyloidosis Subtypes: A Comparative Study of Immunoglobulin Light Chain and Transthyretin Amyloid Cardiomyopathy

BACKGROUND

Speckles tracking echocardiography imaging enables clinicians to detect subtle systolic dysfunction. The aim of the present study was to elucidate the differences in speckle tracking echocardiographic findings between immunoglobulin light chain amyloid cardiomyopathy (AL-CM) and transthyretin amyloid cardiomyopathy (TTR-CM).

METHODS

The patients with a confirmed diagnosis of cardiac amyloidosis through cardiac biopsy from March 2013 to October 2022 were included. The relative apical sparing index (RASI) was calculated using speckle tracking echocardiography by the following equation; average apical strain/(average basal strain + mid strain).

RESULTS

The final study population consisted of 35 patients with cardiac amyloidosis (AL-CM: 10 patients, TTR-CM: 25 patients). The mean age was 74 ± 12 years. Although both subgroups had a gradual change of strain values from basal to apical segments, RASI was significantly lower in AL-CM compared to TTR-CM (0.92 ± 0.29 vs. 1.46 ± 0.53, p = 0.001). A RASI cutoff value of <1.0 proved useful in differentiating the diagnosis of AL-CM from TTR-CM (sensitivity: 81%, specificity: 70%, AUC: 0.82). A significant positive correlation with left ventricular mass index and RASI was found in AL-CM, but not in TTR-CM.

CONCLUSION

The apical sparing phenomenon was more remarkable in TTR-CM compared with AL-CM. RASI might be useful for the discrimination of cardiac amyloidosis subtypes. There was a difference in the relationship of RASI with left ventricular wall thickness between the cardiac amyloidosis subtypes.

Role of biomarkers in early diagnosis and prognosis of cardiac amyloidosis: A systematic review and meta-analysis

BACKGROUND

Cardiac amyloidosis is characterized by amyloid fibril deposition in the heart, leading to restrictive cardiomyopathy and heart failure. Early diagnosis and monitoring are crucial for effective management. This systematic review and meta-analysis evaluates the utility of various biomarkers in the early detection, disease progression, and prognosis of cardiac amyloidosis.

METHODS

We conducted a comprehensive search of PubMed, Scopus, and Web of Science databases for studies published between 2000 and 2024 that assessed the diagnostic and prognostic value of biomarkers in cardiac amyloidosis. Data were extracted and analyzed to determine the sensitivity, specificity, and prognostic significance of each biomarker. The correlation between biomarker levels and imaging findings was also explored.

RESULTS

A total of 45 studies were included in the meta-analysis. NT-proBNP and troponins had high sensitivity and specificity for early diagnosis of cardiac amyloidosis. Novel biomarkers, such as serum amyloid P component and light-chain assays, showed promise in distinguishing between amyloidosis subtypes and predicting disease progression. However, significant variability existed in the correlation between biomarkers and imaging findings.

CONCLUSIONS

Biomarkers are crucial for early diagnosis and prognosis of cardiac amyloidosis. NT-proBNP and troponins are well-established markers, while novel biomarkers offer additional insights into disease progression and subtype differentiation.

Detection of cardiac amyloidosis using machine learning on routine echocardiographic measurements

BACKGROUND

Cardiac amyloidosis (CA) is an underdiagnosed, progressive and lethal disease. Machine learning applied to common measurements derived from routine echocardiogram studies can inform suspicion of CA.

OBJECTIVES

Our objectives were to test a random forest (RF) model in detecting CA.

METHODS

We used 3603 echocardiogram studies from 636 patients at Cedars-Sinai Medical Center to train an RF model to predict CA from echocardiographic parameters. 231 patients with CA were compared with 405 control patients with negative pyrophosphate scans or clinical diagnosis of hypertrophic cardiomyopathy. 19 common echocardiographic measurements from echocardiogram reports were used as input into the RF model. Data was split by patient into a training data set of 2882 studies from 486 patients and a test data set of 721 studies from 150 patients. The performance of the model was evaluated by area under the receiver operative curve (AUC), sensitivity, specificity and positive predictive value (PPV) on the test data set.

RESULTS

The RF model identified CA with an AUC of 0.84, sensitivity of 0.82, specificity of 0.73 and PPV of 0.76. Some echocardiographic measurements had high missingness, suggesting gaps in measurement in routine clinical practice. Features that were large contributors to the model included mitral A-wave velocity, global longitudinal strain (GLS), left ventricle posterior wall diameter end diastolic (LVPWd) and left atrial area.

CONCLUSION

Machine learning on echocardiographic parameters can detect patients with CA with accuracy. Our model identified several features that were major contributors towards identifying CA including GLS, mitral A peak velocity and LVPWd. Further study is needed to evaluate its external validity and application in clinical settings.

Diversity of heart failure phenotypes in transthyretin amyloid cardiomyopathy. More than just heart failure with preserved ejection fraction

INTRODUCTION

Current guidelines recommend suspecting transthyretin amyloid cardiomyopathy (ATTR-CM) in patients over 65 years of age with unexplained left ventricular (LV) hypertrophy in a non-dilated LV, heart failure (HF) and preserved ejection fraction (HFpEF), hypertrophic cardiomyopathy or severe aortic stenosis. However, there is evidence indicating a high prevalence of ATTR-CM in other HF phenotypes. As such, this study aimed to characterize the diversity of HF phenotypes of ATTR-CM by examining the LV ejection fraction and LV dilatation using echocardiography.

METHODS

This multicentre, retrospective observational study included patients diagnosed with ATTR-CM between 2015-2023. The diagnosis was based on a positive cardiac biopsy or positive bone scintigraphy without monoclonal gammopathy. Echocardiographic measurements were categorized according to LV ejection fraction (LVEF) into HFpEF (LVEF ≥50%), HF with mildly reduced EF (HFmrEF, LVEF 40-49%), and HF with reduced EF (HFrEF, LVEF <40%). LV cavity size was categorized by LV end-diastolic diameter (LVEDD) and volume index (LVEDVi) as normal, moderately increased and severe dilatation.

RESULTS

The study included 135 patients with ATTR-CM (mean age, 78 years; 89% male; 89% wild-type ATTR-CM). Most patients were screened for ATTR-CM because of unexplained HF and increased LV wall thickness (57%). Echocardiography showed LVEF <50% in 60% of the patients, with a significant portion presenting with HFrEF. Patients with LVEF <50% had higher NYHA class and elevated N-terminal pro-B-type natriuretic peptide levels than HFpEF patients. LV dilatation was observed in 43% of the patients, with 10% presenting with both LVEF <50% and severe LV dilatation.

CONCLUSION

This study revealed significant variability in HF phenotypes among patients with ATTR-CM, from HFpEF without LV dilatation to HFrEF with severe LV dilatation. Relying solely on HFpEF for screening may lead to under-diagnosis. These findings suggest the need for more comprehensive diagnostic criteria beyond echocardiographic measures to improve ATTR-CM detection and management.

Changes in the diagnostic trajectory of transthyretin cardiac amyloidosis over six years

Awareness of transthyretin amyloid cardiomyopathy (ATTR-CM) has increased over the years due to diagnostic and therapeutic developments. Timely initiation of novel disease-modifying treatments improves both morbidity and mortality, which underlines the necessity for a prompt diagnosis. Nevertheless, early diagnosis of ATTR-CM remains challenging. This is a retrospective observational cohort study of patients diagnosed with ATTR-CM. Between 2016 and 2023, 87 patients were diagnosed with cardiac amyloidosis of which 65 (75%) patients with ATTR-CM and 22 (25%) patients with light chain amyloidosis. This study included 65 ATTR-CM patients (mean age 77 ± 7 years; 86% male) of whom 59 (91%) with wild-type ATTR-CM (ATTRwt) and six (9%) with variant ATTR-CM. We observed a surge in ATTR-CM diagnoses from 3 patients/year (2016-2020) to 16 patients/year (2021-2023), driven by ATTRwt. Nevertheless, the interval between the onset of heart failure symptoms and ATTR-CM diagnosis has not changed significantly (2016-2020 27.3 months [18.6-62.4]; 2021-2023 30.0 months [8.6-57.2]; p = 0.546), driven by time to referral. Red flags for ATTR-CM preceded diagnosis by several years: left ventricular hypertrophy (79%, 5.8 years [3.3-7.0]) and carpal tunnel syndrome (49%, 6.8 years [2.3-12.1]). Despite the presence of typical red flags, symptom-to-diagnosis duration has remained similar driven by time to referral. Improved recognition of red flags for ATTR-CM could reduce the time to diagnosis and improve overall recognition.

Tafamidis therapy in transthyretin amyloid cardiomyopathy: a narrative review from clinical trials and real-world evidence

BACKGROUND

Amyloidosis is a heterogeneous group of disorders caused by the extracellular deposition of insoluble misfolded proteins, leading to end-organ damage. Transthyretin amyloid cardiomyopathy (ATTR-CM) is a subtype in which a protein known as transthyretin accumulates within the heart tissue, progressively resulting in restrictive cardiomyopathy and heart failure. Due to the progressive nature of ATTR-CM, clinical management requires efficacious regimens to manage the debilitating condition and Tafamidis shows promising results in this regard.

MAIN BODY

ATTR-CM poses a significant challenge due to its nature and limited therapeutic options. Tafamidis is a novel therapy designed to stabilize the transthyretin tetramers, inhibiting the formation of amyloid fibrils. It has emerged as a promising treatment and the only FDA-approved drug for ATTR-CM. Tafamidis' role in slowing disease progression and improving outcomes in patients with ATTR-CM has been demonstrated in the major randomized control trial ATTR-ACT with promising open-label extension studies, some still ongoing. Additionally, real-world evidence supports its use in clinical practice, showing its role in reducing morbidity and mortality associated with this condition. Clinical evidence shows its efficacy in improving symptoms and cardiac function in patients. Case studies also reveal significant benefits to patients like reducing myocardial damage, reversal of atrial fibrillation, and resolution of heart failure symptoms. Real-world outcomes and clinical trials show a consistent reduction in amyloid deposition, cardiovascular-related hospitalizations, and all-cause mortality with Tafamidis therapy.

CONCLUSION

Tafamidis is an essential component of the treatment of ATTR-CM and this narrative review synthesizes the current evidence regarding safety, efficacy, and utilization in real practice. While it shows promising effects, its effectiveness may also vary and high cost precludes real-world large-scale studies. Overall, Tafamidis emerges as a valuable therapeutic option for managing ATTR-CM.

Diagnostic value of late gadolinium enhancement at cardiovascular magnetic resonance to distinguish arrhythmogenic right ventricular cardiomyopathy from differentials

BACKGROUND

While late gadolinium enhancement (LGE) is proposed as a diagnostic criterion for arrhythmogenic right ventricular cardiomyopathy (ARVC), the potential of LGE to distinguish ARVC from differentials remains unknown. We aimed to assess the diagnostic value of LGE for ARVC diagnosis.

METHODS

We included 132 subjects (60% male, 47 ± 11 years) who had undergone cardiac magnetic resonance imaging with LGE assessment for ARVC or ARVC differentials. ARVC was diagnosed as per 2010 Task Force Criteria (n = 55). ARVC differentials consisted of familial/genetic dilated cardiomyopathy (n = 25), myocarditis (n = 13), sarcoidosis (n = 20), and amyloidosis (n = 19). The diagnosis of all differentials was based on the most current standard of reference. The presence of LGE was evaluated using a 7-segment right ventricle (RV) and 17-segment left ventricle (LV) model. Subsequently, we assessed LGE patterns for every patient individually for fulfilling LV- and/or RV-LGE per Padua criteria, independent of their clinical diagnosis (i.e. phenotype). Diagnostic values were analyzed using sensitivity and specificity for any RV-LGE, any LV-LGE, RV-LGE per Padua criteria, and prevalence graphs for LV-LGE per Padua criteria. The optimal integration of LGE for ARVC diagnosis was determined using classification and regression tree analysis.

RESULTS

One-third (38%) of ARVC patients had RV-LGE, while half (51%) had LV-LGE. RV-LGE was less frequently observed in ARVC vs non-ARVC patients (38% vs 58%, p = 0.034) leading to a poor discriminatory potential (any RV-LGE: sensitivity 38%, specificity 42%; RV-LGE per Padua criteria: sensitivity 36%, specificity 44%). Compared to ARVC patients, non-ARVC patients more often had LV-LGE (91% vs 51%, p < 0.001) which was also more globally distributed (median 9 [interquartile range (IQR): 3-13] vs 0 [IQR: 0-3] segments, p < 0.001). The absence of anteroseptal and absence of extensive (≥5 segments) mid-myocardial LV-LGE, and absence of moderate (≥2 segments) mid-myocardial LV-LGE predicted ARVC with good diagnostic performance (sensitivity 93%, specificity 78%).

CONCLUSION

LGE is often present in ARVC differentials and may lead to false positive diagnoses when used without knowledge of LGE patterns. Moderate RV-LGE without anteroseptal and mid-myocardial LV-LGE is typically observed in ARVC.

Detection of cardiac amyloidosis on routine bone scintigraphy: an important gatekeeper role for the nuclear medicine physician

Cardiac amyloidosis (CA)-mostly transthyretin-related (ATTR-CA)-has recently gained interest in cardiology. Bone scintigraphy (BS) is one of the main screening tools for ATTR-CA but also used for various other reasons. The objective was to evaluate whether all CA cases are detected and what happens during follow-up. All routine BS performed at the Maastricht University Medical Center (May 2012-August 2020) were screened for the presence of CA. Scans performed for suspected CA were excluded. A Perugini stage ≥1 was classified as positive necessitating further examination. The electronic medical record system was evaluated for any contact with cardiology or other specialists until 2021. Of the 2738 BS evaluated, 40 scans (1.46%; median age 73.5 [IQR: 65.8-79.5], 82.5% male) were positive (Perugini grade 1: 31/77.5%, grade 2: 6/15%, grade 3: 3/7.5%); the potential diagnosis ATTR-CA was not seen in 38 patients (95%) by the nuclear medicine specialist. During follow-up, 19 out of those 40 patients (47.5%) underwent cardiac evaluation without diagnosing CA. Available echocardiograms of patients with a positive BS showed left ventricular hypertrophy, a preserved ejection fraction, and diastolic dysfunction ≥2 in 9/47%, 10/53%, and 4/21% of patients, respectively. Additionally, 20 (50%) patients presented to at least one specialty with symptoms indicative of cardiac amyloidosis. The prevalence of a positive BS indicating potential CA in an unselected population is low but substantial. The majority was not detected which asks for better awareness for CA of all involved specialists to ensure appropriate treatment and follow-up.

Cardiac amyloidosis at a glance

Amyloidosis can affect any organ in the body by deposition of amyloid fibrils. When these aggregate in the heart, it leads to cardiac amyloidosis a life-threatening and progressive disease. Although considered a rare condition, advances in imaging techniques and raised awareness have shown that it might be more frequent than has been historically estimated. Cardiac amyloidosis can be hereditary or occur as a consequence of the ageing process but, regardless of type, patients experience a heavy symptomatic burden. This article provides an overview of its pathophysiology, signs and symptoms and how any nurse can look for the main red flags in clinical practice. Early referral for specialist care can have a significant impact on disease progression and patient quality of life.

Clinical Outcomes of Percutaneous Coronary Intervention in Amyloidosis, Sarcoidosis, and Hemochromatosis

Background

Infiltrative diseases (IDs), including amyloidosis, sarcoidosis, and hemochromatosis, are characterized by abnormal cellular infiltration in multiple organs, including the heart. The prognosis of percutaneous coronary intervention (PCI) patients with underlying IDs has not been well-studied. We evaluated the prevalence of IDs in patients undergoing PCI and their association with post-PCI outcomes.

Methods

The National Inpatient Sample (NIS) 2016-2020 database was used to identify PCI patients with ICD-10 codes for a retrospective analysis. PCI patients were then divided into those with and without underlying IDs, which included amyloidosis, sarcoidosis, and hemochromatosis. Multivariable logistic regression was performed for composite post-PCI outcomes analyses.

Results

Among 2,360,860 patients admitted to undergo PCI, 7855 patients had underlying IDs. The highest prevalence was observed for sarcoidosis (0.2%) followed by hemochromatosis (0.07%) and amyloidosis (0.04%). Underlying amyloidosis was associated with worse composite post-PCI outcomes (odds ratio [OR], 1.6; 95% CI, 1.1-2.44; P = .02), including higher in-hospital mortality (OR, 1.9; 95% CI, 1.1-3.4; P = .04), higher risk of intra/post-PCI stroke (OR, 4.0; 95% CI, 1.1-16.0; P = .04), but not major bleeding (OR, 2.2; 95% CI, 0.97-5.03; P = .058). In contrast, underlying sarcoidosis (OR, 1.1; 95% CI, 0.87-1.41; P = .4), and hemochromatosis (OR, 1.18; 95% CI, 0.77-1.8; P = .44) were not associated with composite post-PCI outcomes. Amyloidosis patients undergoing PCI also had higher hospitalization charges ($212,123 vs $141,137; P = .03) and longer length of stay (8.2 vs 3.9 days; P < .001).

Conclusions

Underlying amyloidosis was associated with worse post-PCI outcomes including higher in-hospital mortality, intra/post-PCI stroke, and socioeconomic burden. A multidisciplinary approach and future studies are needed to investigate the screening and treatment strategies in these patients.

A wolf in sheep's clothing-aortic stenosis and cardiac amyloidosis: "RAISE"ing awareness in clinical practice

Aesop's fable of the wolf in sheep's clothing encourages us to look beneath the exterior appearance of a situation and evaluate the truth that lies beneath. This concept should be applied when managing older patients with severe aortic stenosis. This population of patients is increasingly being identified as having concomitant cardiac amyloidosis, which is an underrecognized cause of common cardiac conditions. The presence of cardiac amyloidosis negatively affects the outcome of patients with aortic stenosis, these patients undergo transcatheter aortic valve replacement (TAVR) with increasing frequency and have a significantly higher overall mortality rate than patients with aortic stenosis alone. Although left ventricular wall hypertrophy is expected in patients with aortic stenosis, it should not be assumed that this is caused only by aortic stenosis. A suspicion of cardiac amyloidosis should be raised in patients in whom the degree of hypertrophy is disproportionate to the degree of aortic stenosis severity. The remodeling, age, injury, systemic, and electrical (RAISE) score was developed to predict the presence of cardiac amyloidosis in patients with severe aortic stenosis. This article highlights the value of increased clinical suspicion, demonstrates the use of the multiparameter RAISE score in daily clinical practice, and illustrates the scoring system with case studies. In elderly patients being considered for TAVR, systematic testing for cardiac amyloidosis should be considered as part of the preoperative workup.

Transthyretin Cardiac Amyloidosis Disguised as Light Chain Amyloidosis or Multiple Myeloma?

We describe 2 challenging cases of cardiac transthyretin amyloidosis initially treated as cardiac amyloidosis light chain in the setting of active myeloma. Endomyocardial biopsy with mass spectrometry was essential to confirm the appropriate diagnosis to direct the treatment.

Examining the Difficulties in Identifying and Handling Cardiac Amyloidosis; Acquiring Important Knowledge and Robust Treatment Methods

Systemic amyloidosis is a rare protein misfolding and deposition condition that causes slow organ failure. Each of the more than 15 exclusive sorts of systemic amyloidosis, which encourage amyloid production and tissue deposition, is introduced by a unique precursor protein. Amyloidosis can affect various organs, including the heart, kidneys, liver, nerves, gastrointestinal tract, lungs, muscles, skin, and soft tissues. It can either be acquired or hereditary. Insidious and doubtful signs often cause a put-off in diagnosis. In the closing decade, noteworthy progressions have been made in the identity, prediction, and handling of amyloidosis. Shotgun proteomics based on mass spectrometry has revolutionized amyloid typing and enabled the identification of novel amyloid forms. It is critical to correctly identify the precursor protein implicated in amyloidosis because the kind of protein influences the proper treatment strategy. Cardiac amyloidosis is a disorder characterized by the systemic accumulation of amyloid protein in the myocardium's extracellular space, which causes a variety of symptoms. The buildup of amyloid aggregates precipitates myocardial thickening and stiffening, culminating in diastolic dysfunction and, in due course, heart failure. We examine every kind of systemic amyloidosis in this text to offer practitioners beneficial equipment for diagnosing and treating those unusual diseases. This review presents a comprehensive analysis of cardiac amyloidosis and consolidates current methods for screening, diagnosis, evaluation, and treatment alternatives.

Patient Journey Toward a Diagnosis of Light Chain Amyloidosis in a National Sample: Cross-Sectional Web-Based Study

BACKGROUND

Systemic light chain (AL) amyloidosis is a rare and multisystem disease associated with increased morbidity and a poor prognosis. Delayed diagnoses are common due to the heterogeneity of the symptoms. However, real-world insights from Chinese patients with AL amyloidosis have not been investigated.

OBJECTIVE

This study aimed to describe the journey to an AL amyloidosis diagnosis and to build an in-depth understanding of the diagnostic process from the perspective of both clinicians and patients to obtain a correct and timely diagnosis.

METHODS

Publicly available disease-related content from social media platforms between January 2008 and April 2021 was searched. After performing data collection steps with a machine model, a series of disease-related posts were extracted. Natural language processing was used to identify the relevance of variables, followed by further manual evaluation and analysis.

RESULTS

A total of 2204 valid posts related to AL amyloidosis were included in this study, of which 1968 were posted on haodf.com. Of these posts, 1284 were posted by men (median age 57, IQR 46-67 years); 1459 posts mentioned renal-related symptoms, followed by heart (n=833), liver (n=491), and stomach (n=368) symptoms. Furthermore, 1502 posts mentioned symptoms related to 2 or more organs. Symptoms for AL amyloidosis most frequently mentioned by suspected patients were nonspecific weakness (n=252), edema (n=196), hypertrophy (n=168), and swelling (n=140). Multiple physician visits were common, and nephrologists (n=265) and hematologists (n=214) were the most frequently visited specialists by suspected patients for initial consultation. Additionally, interhospital referrals were also commonly seen, centralizing in tertiary hospitals.

CONCLUSIONS

Chinese patients with AL amyloidosis experienced referrals during their journey toward accurate diagnosis. Increasing awareness of the disease and early referral to a specialized center with expertise may reduce delayed diagnosis and improve patient management.

Uneven burden of cardiac amyloidosis in people of African descent - global imbalance in resources and access

Transthyretin cardiac amyloidosis (TTR-CA) is now increasingly becoming recognized as an important cause of heart failure, and some studies have shown that as much as a third of diastolic heart failure could be attributed to TTR-CA. Black populations are particularly at risk for TTR-CA as the most common form of the disease (hereditary TTR-CA) has a genetic basis and the gene responsible is most prevalent among people with West African ancestry. This perspective piece explores the challenges that individuals of African and Caribbean populations face when confronted with the burden of TTR-CA. Key issues include the absence of rigorous disease registries, deficits in human resources, a lack of infrastructure for testing and treatment, poor awareness and health literacy, financial limitations including an inadequate public health budget, and the absence of social safety nets. To address these challenges, proactive strategies are needed to build infrastructure and local capacity which will provide the framework for an effective response. Interventions should include healthcare financing mechanisms to protect and care for vulnerable and at-risk populations with a long-term strategy of increasing the financial remuneration for health workers in developing countries to prevent the brain drain. Additionally, pharmaceutical companies need to play an active role in promoting inclusive access and global health equity in the access to the new treatments for TTR-CA which predominantly affects Black populations. Collaborative ventures with international centers of excellence can help improve access in these communities, leveraging their expertise and resources.

Diagnosis and referral of patients with AL amyloidosis in Portugal: results from a Delphi panel

Light chain amyloidosis (AL) is a complex disorder defined by the extracellular deposition of insoluble amyloid fibrils formed by intact or fragmented immunoglobulin light chains, leading to cell dysfunction, rapid organ deterioration, and, ultimately, death. Although the clinical presentation of AL is directly connected to organ involvement, signs and symptoms of AL are frequently nonspecific, misinterpreted, and late recognized. Thus, an early diagnosis combined with effective therapies to cease disease progression and rescue organ function is essential. The aim of this study was to assess the knowledge and characterize the current clinical practice regarding AL diagnosis and referral among Portuguese physicians. A Delphi-like panel (one round only) with a group of national experts from different medical specialties (cardiology, hematology, internal medicine, nephrology, and neurology) was carried out online, in which 30 statements were classified using a 4-point Likert scale. For each statement, the consensus level was set at 70% for "fully agree/disagree" and the majority level was defined as >70% in agreement or disagreement. Although the results suggest the existence of adequate general knowledge of AL amyloidosis, they also disclosed the necessity to raise awareness for this disease. Overall, this Delphi panel revealed a high lack of consensus regarding the diagnosis and early management of patients with AL among different specialties despite the qualified majority obtained in 26 statements. An optimized strategy for AL early diagnosis, transversal to several medical fields, is urgently needed. Moreover, referral centers with access to diagnostic technology and a network of diverse specialties should be established to foster an early diagnosis and better disease approach to boost the possibility of a better outcome for patients with AL.

A review of the impact, pathophysiology, and management of atrial fibrillation in patients with heart failure with preserved ejection fraction

Patients with heart failure with preserved ejection fraction (HFpEF) and atrial fibrillation (AF) have increased mortality and increased risk of stroke. Due to the heterogeneous nature of both disease processes, it is difficult to ascertain whether the diagnosis and progression of AF is the cause of deterioration or if it is a symptom of worsening heart failure. This presents physicians with a clinical conundrum of whether optimizing their heart failure will decrease the overall AF burden or if restoration of sinus rhythm is necessary to optimize patients with HFpEF. In this paper, we will review the impact of AF in patients with HFpEF, the pathophysiology and heterogeneity of HFpEF and AF, and the management of these patients. As HFpEF and AF become more prevalent, managing these disease processes needs standardization to improve outcomes. Further research is needed to understand the complex interplay between AF and HFpEF to help determine the best management strategy.

Cardiac amyloidosis: evolving pathogenesis, multimodal diagnostics, and principles of treatment

Amyloidosis is a protein deposition disorder in which insoluble fibril structures accumulate in the bodily tissues damaging the organ function. Cardiac amyloidosis is a severe but under-reported medical condition characterized by the accumulation of amyloid in the extracellular area of the myocardium, which results in thickening and stiffening of ventricular walls. Cardiac amyloidosis has recently gained much attention with its slowly surging incidence. With this study, we seek to comprehensively compile the pathophysiology and clinical picture of cardiac amyloidosis subtypes, extending a clinically oriented, up-to-date clinical approach to diagnosis and therapy. Cardiac amyloidosis can be caused by rare genetic mutations which may be inherited or acquired. The growing incidence can be attributed to advancements in imaging methods and other diagnostic modalities. Most occurrences of cardiac amyloidosis result from two forms of precursor protein: transthyretin [TTR] amyloid and immunoglobulin-derived light-chain amyloid. Prompt identification of cardiac amyloidosis can facilitate the implementation of evolving therapeutic interventions to enhance the outcomes. The modalities for the management of CA have evolved significantly in the last ten years. Apart from therapies for modifying disease and heart failure, a myriad of novel therapeutic approaches that target specific aspects of the disease, including gene therapies, are being researched. These aim at impeding its progression and improving clinical outcomes. See also Figure 1(Fig. 1).

Quantitative SPECT/CT Parameters in the Assessment of Transthyretin Cardiac Amyloidosis-A New Dimension of Molecular Imaging

AIMS

Cardiac transthyretin amyloidosis (ATTR) represents the accumulation of misfolded transthyretin in the heart interstitium. Planar scintigraphy with bone-seeking tracers has long been established as one of the three main steps in the non-invasive diagnosis of ATTR, but lately, single-photon emission computed tomography (SPECT) has gained wide recognition for its abilities to exclude false positive results and offer a possibility for amyloid burden quantitation. We performed a systematic review of the existing literature to provide an overview of the available SPECT-based parameters and their diagnostic performances in the assessment of cardiac ATTR. Methods and Methods: Among the 43 papers initially identified, 27 articles were screened for eligibility and 10 met the inclusion criteria. We summarised the available literature based on radiotracer, SPECT acquisition protocol, analysed parameters and their correlation to planar semi-quantitative indices.

RESULTS

Ten articles provided accurate details about SPECT-derived parameters in cardiac ATTR and their diagnostic potential. Five studies performed phantom studies for accurate calibration of the gamma cameras. All papers described good correlation of quantitative parameters to the Perugini grading system.

CONCLUSIONS

Despite little published literature on quantitative SPECT in the assessment of cardiac ATTR, this method offers good prospects in the appraisal of cardiac amyloid burden and treatment monitoring.

Semi-Quantification of Myocardial Uptake of Bone-Seeking Agents in Suspected Cardiac Amyloidosis

INTRODUCTION

Bone scintigraphy has emerged as a key tool for non-invasive etiologic diagnosis of transthyretin (ATTR) cardiac amyloidosis (CA). We focused on a new semi-quantification method (on planar imaging) that could complement the qualitative/visual Perugini scoring system, especially when SPET/CT is not available.

MATERIAL AND METHODS

We retrospectively/qualitatively evaluated 8674 consecutive, planar 99mTc-biphosphonate scintigraphies (performed for non-cardiac reasons), identifying 68 (0.78%) individuals (mean age 79 ± 7 years, range 62-100 years; female/male ratio 16/52) presenting myocardial uptake. Due to the retrospective nature of the study, no SPET/CT, pathologic or genetic confirmation was obtained. The Perugini scoring system was determined (in patients presenting cardiac uptake) and compared with three newly proposed semi-quantitative indices. We took 349 consecutive bone scintigraphies, qualitatively absent of any cardiac/pulmonary uptake, as "healthy controls" (HC).

RESULTS

The heart-to-thigh ratio (RHT) and lung-to-thigh ratio (RLT) indices were significantly higher in patients than in HCs (p ≤ 0.0001). There were statistically significant differences for RHT in HCs vs. patients with qualitative Perugini scores of 1 or >1 (with p ranging from ≤0.001 to ≤0.0001). ROC curves showed that RHT outperformed the other indices and was more accurate in both male and female groups. Furthermore, in the male population, RHT accurately distinguished HCs and patients with scores of 1 (less likely affected by ATTR) from patients with qualitative scores >1 (more likely affected by ATTR) with an AUC of 99% (sensitivity: 95%; specificity: 97%).

CONCLUSION

The proposed semi-quantitative RHT index can accurately/semi-quantitatively distinguish between HCs and subjects probably affected by CA (Perugini scores from 1 to 3), and could be particularly useful when no SPET/CT data are available (such as in retrospective studies and data mining). Furthermore, RHT can semi-quantitatively predict, with very high accuracy, subjects in the male population more likely to be affected by ATTR. The present study, although using a very large sample, is however retrospective, monocentric, and therefore the generalizability of the results should be proved by an accurate external validation.

ADVANCES IN KNOWLEDGE

The proposed heart-to-thigh ratio (RHT) can distinguish healthy controls and subjects that are probably affected by cardiac amyloidosis in a simple and more reproducible way, as compared to standard qualitative/visual evaluation.

Diagnostic and Prognostic Value of Non-late Gadolinium Enhancement Cardiac Magnetic Resonance Parameters in Cardiac Amyloidosis

Early diagnosis is crucial for the improvement of outcomes of patients with cardiac amyloidosis (CA). Emerging non-late gadolinium enhancement (LGE) based cardiac magnetic resonance (CMR) parameters may facilitate early identification of CA. We sought to investigate the diagnostic and prognostic value of T1, T2 mapping and extracellular volume (ECV) in CA. This single-center prospective analysis included 88 patients with CA, 33 patients with aortic stenosis (AS) and left ventricular hypertrophy (LVH), and 15 healthy controls who completed 3T cardiac MRI at the time of their diagnosis and were assessed with T1, T2 (modified Look-Locker inversion recovery), and ECV mapping of the heart and spleen. Echocardiographic, and biochemical parameters and clinical characteristics and outcomes were collected and analyzed. Of the patients with CA, 71 had light-chain (AL) and 17 had transthyretin (ATTR) amyloidosis. Native T1, native T2 and ECV were significantly higher in patients with CA compared to both patients with LVH-AS (P<0.001) and healthy controls (P<0.001). Good diagnostic accuracy was also demonstrated by measuring the area under the curve (AUC) of the receiver operating characteristic (ROC) curves for native T1 in the region of interest (ROI) (AUC=0.90), native T2 ROI (AUC=0.88), and ECV (AUC=0.90). Furthermore, native T1 ROI, native T2 ROI and ECV, correlated with both NT-proBNP levels and Mayo stage of patients (with AL). Spleen ECV was significantly increased in patients with AL versus ATTR amyloidosis (38.5 vs 30.5; P=0.004) and demonstrated good diagnostic accuracy in differentiating between the two types (AUC=0.79). Native T2 ROI was prognostic of mortality in AL CAwith a HR of 1.97 per 5 ms increase (P=0.001) and remained prognostic after adjustment for age, and Mayo stage. Non-LGE based CMR techniques correlated with established markers of disease and demonstrated good diagnostic accuracy, while native T2 ROI was also prognostic of mortality, thus reinforcing their use in the diagnosis and prognosis of CA.

Machine Learning Approaches in Diagnosis, Prognosis and Treatment Selection of Cardiac Amyloidosis

Cardiac amyloidosis is an uncommon restrictive cardiomyopathy featuring an unregulated amyloid protein deposition that impairs organic function. Early cardiac amyloidosis diagnosis is generally delayed by indistinguishable clinical findings of more frequent hypertrophic diseases. Furthermore, amyloidosis is divided into various groups, according to a generally accepted taxonomy, based on the proteins that make up the amyloid deposits; a careful differentiation between the various forms of amyloidosis is necessary to undertake an adequate therapeutic treatment. Thus, cardiac amyloidosis is thought to be underdiagnosed, which delays necessary therapeutic procedures, diminishing quality of life and impairing clinical prognosis. The diagnostic work-up for cardiac amyloidosis begins with the identification of clinical features, electrocardiographic and imaging findings suggestive or compatible with cardiac amyloidosis, and often requires the histological demonstration of amyloid deposition. One approach to overcome the difficulty of an early diagnosis is the use of automated diagnostic algorithms. Machine learning enables the automatic extraction of salient information from “raw data” without the need for pre-processing methods based on the a priori knowledge of the human operator. This review attempts to assess the various diagnostic approaches and artificial intelligence computational techniques in the detection of cardiac amyloidosis.

Detection and Diagnosis of Cardiac Amyloidosis in Egypt

Cardiac amyloidosis is a life-threatening disease that occurs when amyloid proteins, most commonly immunoglobulin light chain or transthyretin, mutate or become unstable, misfold, deposit as amyloid fibrils, and accumulate in the myocardium. Early diagnosis of cardiac amyloidosis is hindered by insufficient awareness, specifically regarding clinical red flags and diagnostic pathways. Cardiac amyloidosis diagnosis comprises two important phases, clinical suspicion (phase one) followed by definitive diagnosis (phase two). Each phase is associated with specific clinical techniques. For example, clinical features, electrocardiography, echocardiography, and cardiac magnetic resonance imaging serve to raise suspicion of cardiac amyloidosis and facilitate early diagnosis, whereas laboratory tests (i.e., blood or urine electrophoresis with immunofixation), biopsy, scintigraphy-based nuclear imaging, and genetic testing provide a definitive diagnosis of cardiac amyloidosis. In Egypt, both the lack of cardiac amyloidosis awareness amongst healthcare providers and the unavailability of clinical expertise for the use of diagnostic techniques must be overcome to improve the prognosis of cardiac amyloidosis in the region. Previously published diagnostic algorithms for cardiac amyloidosis have amalgamated techniques that can raise clinical suspicions of cardiac amyloidosis with those that definitively diagnose cardiac amyloidosis. Though such algorithms have been successful in developed countries, diagnostic tools like echocardiography, scintigraphy, and cardiac magnetic resonance imaging are not ubiquitously available across Egyptian facilities. This review presents the current state of knowledge regarding cardiac amyloidosis in Egypt and outlines a new diagnostic algorithm which leverages regional nuclear imaging expertise. Importantly, the proposed diagnostic algorithm guides accurate amyloid-typing to mitigate misdiagnosis and erroneous treatment selection and improve the cardiac amyloidosis diagnostic accuracy in Egypt.

Impaired Extracellular Proteostasis in Patients with Heart Failure

BACKGROUND

Proteostasis impairment and the consequent increase of amyloid burden in the myocardium have been associated with heart failure (HF) development and poor prognosis. A better knowledge of the protein aggregation process in biofluids could assist the development and monitoring of tailored interventions.

AIM

To compare the proteostasis status and protein's secondary structures in plasma samples of patients with HF with preserved ejection fraction (HFpEF), patients with HF with reduced ejection fraction (HFrEF), and age-matched individuals.

METHODS

A total of 42 participants were enrolled in 3 groups: 14 patients with HFpEF, 14 patients with HFrEF, and 14 age-matched individuals. Proteostasis-related markers were analyzed by immunoblotting techniques. Fourier Transform Infrared (FTIR) Spectroscopy in Attenuated Total Reflectance (ATR) was applied to assess changes in the protein's conformational profile.

RESULTS

Patients with HFrEF showed an elevated concentration of oligomeric proteic species and reduced clusterin levels. ATR-FTIR spectroscopy coupled with multivariate analysis allowed the discrimination of HF patients from age-matched individuals in the protein amide I absorption region (1700-1600 cm^-1), reflecting changes in protein conformation, with a sensitivity of 73 and a specificity of 81%. Further analysis of FTIR spectra showed significantly reduced random coils levels in both HF phenotypes. Also, compared to the age-matched group, the levels of structures related to fibril formation were significantly increased in patients with HFrEF, whereas the β-turns were significantly increased in patients with HFpEF.

CONCLUSION

Both HF phenotypes showed a compromised extracellular proteostasis and different protein conformational changes, suggesting a less efficient protein quality control system.

Cardiac Amyloidosis: A Rare TTR Mutation Found in an Asian Female

BACKGROUND

Transthyretin cardiac amyloidosis (ATTR) is a life-threatening, debilitating disease caused by abnormal formation and deposit of transthyretin (TTR) protein in multiple tissues, including myocardial extracellular matrix. It can be challenging to diagnose due to the myriad of presenting signs and symptoms. Additionally, numerous TTR mutations exist in certain ethnicities. Interestingly, our patient was discovered to have a very rare Gly67Ala TTR mutation typically not found in individuals of Asian descent. Recent advances in cardiovascular imaging techniques have allowed for earlier recognition and, therefore, management of this disease. Although incurable, there are now new, emerging treatments that are available for symptom control of cardiac amyloidosis, making early diagnosis vital for these patients, specifically their quality of life.

CASE SUMMARY

We outline a case of a 50-year-old Asian female who was initially hospitalized for nausea and vomiting and persistent orthostatic hypotension. She underwent a multitude of laboratory and imaging tests, resulting in a diagnosis of cardiac amyloidosis, which was confirmed to be due to a rare TTR mutation via genetic testing.

CONCLUSIONS

Our objective is to describe various TTR mutations, existing diagnostic imaging modalities, and available treatments, as well as highlight the importance of early screening and awareness of cardiac amyloidosis, allowing for quicker diagnosis and treatment of this disease.

Role of Diphosphonates Bone Scintigraphy in Correlation with Biomarkers for a Personalized Approach to ATTR Cardiac Amyloidosis in North-Eastern Romania

Transthyretin cardiac amyloidosis (ATTR) is a rare cardiac protein deposition disease characterized by progressive thickening of both ventricles, the inter-atrial-ventricular septum and the atrioventricular valves. The gold standard method for diagnosing this rare pathology is endomyocardial biopsy. If this method cannot be used, the alternative is a mixture of clinical and paraclinical tests. Over the course of five years, we examined 58 patients suspected of cardiac amyloidosis based on electrocardiography and ultrasonography criteria, who had been sent for bone scintigraphy in order to determine the presence of ATTR cardiac amyloidosis. However, the final diagnosis was set by correlating the bone scan with genetic testing, free light chain dosage or soft tissue biopsy. Based on the final diagnosis we analyzed the patients' predominant biomarkers in order to determine a possible correlation between them. This analysis is designed to help the general practitioner set a possible cardiac amyloidosis diagnosis.

A Review of Cardiac Amyloidosis: Presentation, Diagnosis, and Treatment

Amyloidosis is a group of disorders that can affect almost any organ due to the misfolding of proteins with their subsequent deposition in various tissues, leading to various disease manifestations based on the location. When the heart is involved, amyloidosis can manifest with a multitude of presentations such as heart failure, arrhythmias, orthostatic hypotension, syncope, and pre-syncope. Diagnosis of cardiac amyloidosis can be difficult due to the non-specific nature of symptoms and the relative rarity of the disease. Amyloidosis can remain undiagnosed for years, leading to its high morbidity and mortality due to this delay in diagnosis. Newer imaging modalities, such as cardiac magnetic resonance imaging, advanced echocardiography, and biomarkers, make a timely cardiac amyloidosis diagnosis more feasible. Many treatment options are available, which have provided new hope for this patient population. This manuscript will review the pathology, diagnosis, and treatment options available for cardiac amyloidosis and provide a comprehensive overview of this complicated disease process.

Noninvasive Diagnostics of Renal Amyloidosis: Current State and Perspectives

Amyloidoses is a group of diseases characterized by the accumulation of abnormal proteins (called amyloids) in different organs and tissues. For systemic amyloidoses, the disease is related to increased levels and/or abnormal synthesis of certain proteins in the organism due to pathological processes, e.g., monoclonal gammopathy and chronic inflammation in rheumatic arthritis. Treatment of amyloidoses is focused on reducing amyloidogenic protein production and inhibition of its aggregation. Therapeutic approaches critically depend on the type of amyloidosis, which underlines the importance of early differential diagnostics. In fact, the most accurate diagnostics of amyloidosis and its type requires analysis of a biopsy specimen from the disease-affected organ. However, absence of specific symptoms of amyloidosis and the invasive nature of biomaterial sampling causes the late diagnostics of these diseases, which leads to a delayed treatment, and significantly reduces its efficacy and patient survival. The establishment of noninvasive diagnostic methods and discovery of specific amyloidosis markers are essential for disease detection and identification of its type at earlier stages, which enables timely and targeted treatment. This review focuses on current approaches to the diagnostics of amyloidoses, primarily with renal involvement, and research perspectives in order to design new specific tests for early diagnosis.

An echo score raises the suspicion of cardiac amyloidosis in Chinese with heart failure with preserved ejection fraction

AIMS

Transthyretin cardiac amyloidosis (ATTR-CA) has been realized as an important cause of heart failure with preserved ejection fraction (HFpEF). We aim to provide insights into its prevalence in Chinese HFpEF patients, which is not known to date, using increased wall thickness (IWT) score by echocardiography.

METHODS

Consecutive patients with HFpEF (EF ≥ 40%) and IWT (≥12 mm) were prospectively screened. Echocardiography was performed, and the IWT score incorporated relative wall thickness, E/e' ratio, longitudinal strains, and tricuspid annular plane systolic excursion, and septal apical-to-base ratio was calculated. ATTR-CA was defined as score ≥8 in the absence of serum and urine free light chain.

RESULTS

Six hundred twenty-four HFpEF patients from January 2019 to December 2021 were enrolled, of which 65.2% were males and the median (interquartile range [IQR]) age was 66 (IQR 57, 73) years. Thirty-three patients (5.3%, 95% CI 3.5-7.0%) were with score ≥8, and 33.3% were females. They were younger (58 vs. 69 years, P < 0.001), had higher NT-proBNP (6525.0 vs. 1741.5 pg/mL, P < 0.001) and troponin I (105.2 vs. 27.7 pg/mL, P = 0.001) level, and lower LVEF (47% vs. 57%, P < 0.001) compared with the patients with score <5. In the internal cohort (82 patients) who had undergone scintigraphy, the IWT score ≥8 was shown to have a sensitivity of 85.7% (95% CI 56.2-97.5%) and a specificity of 92.6% (95% CI 83.0-97.3%) for diagnosing CA, and the IWT score <5 had great accuracy in excluding CA with the negative predictive value of 100%, supporting the clinical usefulness of the IWT score to guide further dedicated testing for ATTR-CA.

CONCLUSIONS

The IWT score by echocardiography was an excellent tool for screening ATTR-CA in HFpEF. In Chinese HFpEF patients associated with a hypertrophic phenotype, the proportion of highly suspected ATTR-CA as detected by IWT score ≥8 was 5.3%, lower than the reported prevalence of ATTR-CA in non-Asian patients with the disease.

Prevalence and Risk Factors of Cardiac Amyloidosis in Heart Failure: A Systematic Review and Meta-Analysis

AIMS

Heart failure (HF) is one of the leading causes of mortality worldwide. Heart failure is also one of the most common presentations of cardiac amyloidosis (CA). Contemporary epidemiological data of CA in HF patients is lacking. Hence, this systematic review and meta-analysis was conducted to determine the prevalence of amyloidosis in HF patients, and to clarify the risk factors of concomitant CA and HF.

METHODS

A systematic review and meta-analysis was performed. Studies were retrieved from Medline, EMBASE, Scopus and Cochrane library. The search was not restricted in time, type or language of publication. The prevalence of CA in HF grouped according to diagnostic techniques and risk factors of CA with HF was analysed.

RESULTS

Eleven (11) studies were included, involving 3,303 patients. The pooled prevalence of CA in HF was 13.7%. The overall prevalence of CA in HF with preserved ejection fraction was 15.1%, and that of HF with reduced ejection fraction was 11.3%. The main factors associated with the diagnosis of CA in HF included older age, males, raised NT pro-BNP, increased interventricular septal thickness in diastole, apical sparing, and reduced left ventricular systolic function.

CONCLUSION

A high index of clinical suspicion is required to identify HF patients with CA. Supportive investigations may be helpful when clinically correlated. A considerable proportion of HF patients have CA and certain risk factors may be helpful in increasing suspicions of CA in HF.

Cardiopulmonary Exercise Physiology in AL Amyloidosis Patients with Cardiac Involvement and Its Association with Cardiac Imaging Parameters

Background: Cardiopulmonary exercise testing (CPET) has been widely used for the functional evaluation of patients with heart failure. Patients with amyloidosis and cardiac involvement typically present with heart failure with preserved or mildly reduced ejection fraction. We sought to evaluate the use of CPET parameters in patients with AL amyloidosis for the assessment of disease severity and prognosis and their association with cardiac imaging findings. Methods: A single-center prospective analysis was conducted, which included 23 consecutive ambulatory patients with AL amyloidosis with cardiac involvement, not requiring hospitalization or intravenous diuretics. Patient evaluation included CPET, laboratory testing, echocardiography and cardiac MRI. The cohort was divided according to the presence of high-risk CPET characteristics (below median peak VO2 and above median VE/VCO2). Results: Patients with AL amyloidosis and cardiac involvement (median age was 60 years (56.5% males) had median peak relative VO2 (VO2/kg) of 17.8 mL/kg/min, VE/VCO2 slope of 39.4 and circulatory power of 2362.5 mmHg⋅mL/kg/min. Peak relative VO2 gradually declined across Mayo stages (p = 0.046) and exhibited a significant inverse correlation with NT-proBNP levels (r = −0.52, p = 0.01). Among imaging parameters, peak VO2 positively correlated with global work efficiency (r = 0.61, p < 0.001), and global work index (r = 0.45, p = 0.04). The group of patients with high-risk CPET findings showed evidence of more advanced disease, such as higher NT-proBNP levels (p = 0.007), increased septal and posterior left ventricular wall thickness (p = 0.043 and p = 0.033 respectively) and decreased global work efficiency (p = 0.027) without substantial differences in cardiac MRI parameters. In this group of patients, peak VO2 and VE/VCO2 were not associated significantly with overall survival and cardiac response at one year. Conclusion: In patients with AL amyloidosis, evaluation of exercise capacity with CPET identified a group of patients with more advanced cardiac involvement. The potential of CPET as a risk stratification tool in AL amyloidosis with cardiac involvement warrants further research.

Recovery from AA amyloidosis-cardiomyopathy complexed with unicentric Castleman disease

We report a case of cardiac amyloid A (AA) amyloidosis due to unicentric Castleman disease (UCD) in a patient whose cardiac function was restored 15 years after surgical resection of the mesenteric lymph node lesion. A man in his 40s had recurrent palpitations and fainting spells. ECG revealed torsades de pointes Increased C-reactive protein, interleukin-6 and serum AA levels, and marked concentric thickening of the left ventricular (LV) wall with diastolic restrictive filling pattern were observed. Duodenal biopsy revealed AA amyloid deposits. He had a mesenteric tumour, comprising many plasma cells. He was diagnosed with plasma cell-type UCD associated with secondary AA amyloidosis. C-reactive protein, interleukin-6 and serum AA levels were normalised 2 months postresection. Episodes of lethal ventricular arrhythmias decreased. LV wall thickness was gradually reduced. Approximately 15 years postresection, the LV wall thickness nearly normalised and ventricular arrhythmias disappeared. Better outcomes are expected following surgical tumour resection.

Restrictive Atrial Dysfunction in Cardiac Amyloidosis: Differences between Immunoglobulin Light Chain and Transthyretin Cardiac Amyloidosis Patients

Background: In cardiac amyloidosis, the prevalence of thromboembolic events and atrial fibrillation is higher in transthyretin amyloidosis compared to immunoglobulin light chain amyloidosis. Therefore, we hypothesize that transthyretin cardiac amyloidosis patients have worse atrial function. Purpose: To explore the left atrial function by conventional ultrasound and strain analysis in immunoglobulin light chain- and transthyretin cardiac amyloidosis patients. Methods: In cardiac amyloidosis patients in our Amyloidosis Expert Center, echocardiographic strain analysis was performed using speckle tracking. Results: The data of 53 cardiac amyloidosis patients (83% male, mean age 70 years) were analyzed. Transthyretin cardiac amyloidosis patients (n = 24, 45%) were older (75 ± 5.6 vs. 65 ± 7.2 years, p < 0.001) and had more left ventricular (LV) hypertrophy than immunoglobulin light chain cardiac amyloidosis patients (n = 29, 55%). However, LV systolic and diastolic function did not differ, nor did left atrial dimensions (LAVI 56(24) vs. 50(31) mL/m2). Left atrial reservoir strain was markedly lower in transthyretin cardiac amyloidosis (7.4(6.2) vs. 13.6(14.7), p = 0.017). This association was independent of other measurements of the left atrial and ventricular function. Conclusions: Transthyretin cardiac amyloidosis patients had lower left atrial reservoir function compared to immunoglobulin light chain cardiac amyloidosis patients although the left atrial geometry was similar. Interestingly, this association was independent of left atrial- and LV ejection fraction and global longitudinal strain. Further research is warranted to assess the impact of impaired left atrial dysfunction in transthyretin cardiac amyloidosis on atrial fibrillation burden and prognosis.

Clinical manifestation, economic burden, and mortality in patients with transthyretin cardiac amyloidosis

Background

Transthyretin cardiac amyloidosis, also known as transthyretin cardiomyopathy (ATTR-CM) is a poorly-recognized disease with delayed diagnosis and poor prognosis. This nationwide population-based study aimed to identify disease manifestations, economic burden, and mortality of patients with ATTR-CM.

Methods

Data of newly diagnosed patients with ATTR-CM between 2013 and 2018 from the Korean National Health Insurance Service were used, covering the entire population. Patient characteristics included comorbidities, medical procedures, and medication. Healthcare resource utilization and medical costs were observed as measures of the economic burden. The Kaplan–Meier survival curve and years of potential life lost (YPLL) from the general population were estimated for disease burden with ATTR CM.

Results

A total of 175 newly diagnosed patients with ATTR-CM were identified. The most common cardiac manifestation was hypertension (51.3%), while the most common non-cardiac manifestation was musculoskeletal disease (68.0%). Mean medical costs at the post-cohort entry date were significantly higher than those at the pre-cohort entry date ($1,864 vs. $400 per patient per month (PPPM), p < 0.001). Of the total medical costs during the study period, the proportion of inpatients cost was 12.9 times higher than the outpatients cost ($1,730 and $134 PPPM, respectively). The median survival time was 3.53 years from the first diagnosis of ATTR-CM, and the mean (SD) YPLL was 13.0 (7.7).

Conclusions

Patients with ATTR-CM had short survival and high medical costs. To reduce the clinical and economic burdens, carefully examining manifestations of disease in patients can help with early diagnosis and treatment.

Cardiac Amyloidosis: A Diagnostic Dilemma and the Role of a Novel Electrocardiogram Criterion

Cardiac amyloidosis is an infiltrative disease of the myocardium. Nearly all cases of clinical cardiac amyloidosis are caused by transthyretin amyloidosis or light chain amyloidosis. Clinical manifestations are consistent with those of refractory heart failure secondary to irreversible restrictive cardiomyopathy, autonomic abnormalities as well as neuropathy. Delay in diagnosis is a challenge, as symptoms and signs of cardiac amyloidosis are nonspecific. One of the hallmarks of cardiac amyloidosis is the discordance between the increased left ventricular wall thickness and low QRS voltages on the electrocardiogram. Diagnostic delay may lead to deleterious consequences as prompt therapy, if feasible, would be hampered.

We, therefore, present a case of cardiac amyloidosis presenting with syncope and refractory heart failure to highlight the diagnostic dilemma as well as to stress upon the utility of a novel electrocardiogram criterion that may assist in the diagnosis of cardiac amyloidosis.

Circulating biomarkers in diagnosis and management of cardiac amyloidosis: a review for internist

Cardiac amyloidosis (CA) is due to extracellular myocardial deposition of misfolded proteins resulting in severe cardiac dysfunction and death. The precursors of amyloid fibrils, able of determining a relevant cardiac infiltration, are immunoglobulin-free light chains (AL amyloidosis) and transthyretin (TTR) (both wild and mutated types). The diagnosis of amyloidosis represents a challenge for the clinician given its rarity and its protean clinical presentation, thus an early diagnosis remains a cornerstone for the prognosis of these patients, also in light of the growing available treatments. There is great interest in identifying and applying biomarkers to help diagnose, inform prognosis, guide therapy, and serve as surrogate endpoints in these patients. In AL amyloidosis, biomarkers such as free light chains, natriuretic peptides and troponins are the most extensively studied and validated; they have proved useful in risk stratification, guiding treatment choice and monitoring hematological and organ response. A similar biomarker-based prognostic score is also proposed for ATTR amyloidosis, although studies are small and need to be validated for wild-type and mutant forms.

Magnetic-Resonance-Imaging-Based Left Atrial Strain and Left Atrial Strain Rate as Diagnostic Parameters in Cardiac Amyloidosis

Aims: The present study aims to evaluate magnetic-resonance-imaging (MRI)-assessed left atrial strain (LAS) and left atrial strain rate (LASR) as potential parameters for the diagnosis of cardiac amyloidosis (CA), the distinction of clinical subtypes and differentiation from other cardiomyopathies. Methods and results: LAS and LASR were assessed by MRI feature tracking in patients with biopsy-proven CA. LAS and LASR of patients with CA were compared to healthy subjects and patients with hypertrophic cardiomyopathy. LAS and LASR were also analyzed concerning differences between patients with transthyretin (ATTR) and light chain amyloidosis (AL). A total of 44 patients with biopsy-proven CA, 19 patients with hypertrophic cardiomyopathy and 24 healthy subjects were included. In 22 CA patients (50%), histological examination identified ATTR as CA subtype and AL in the remaining patients. No significant difference was observed for reservoir, conduit or booster LAS in patients with AL or ATTR. Reservoir LAS, conduit LAS and booster LAS were significantly reduced in patients with CA and HCM as compared to healthy subjects (p < 0.001). Reservoir LAS and booster LAS were significantly reduced in CA as compared to HCM patients (p < 0.001). A linear correlation was observed between LA global reservoir strain and LA-EF (p < 0.001, r = 0.5), conduit strain and global longitudinal LV strain (p < 0.001, r = 0.5), global booster strain rate and LA-EF (p < 0.001, r = 0.6) and between global booster strain rate and LA area at LVED (p < 0.0001, 0.5). Conclusions: LAS and LASR are severely impaired in patients with CA. The MRI-based assessment of LAS and LASR might allow non-invasive diagnosis and categorization of CA and its distinct differentiation from other hypertrophic phenotypes.

Correlation of Quantitative 99mTc DPD Scintigraphy With Echocardiographic Alterations in Left Atrial Parameters in Transthyretin Amyloidosis

AIM

Cardiac transthyretin amyloidosis (ATTR) patients have high rates of atrial arrhythmias. We evaluated echocardiographic structural and functional left atrial (LA) parameters and correlated these with technetium-99m 3,3-diphosphono-1,2-propanodicarboxylic acid (^99mTc-DPD) bone scintigraphy tracer uptake within the LA in ATTR patients.

METHODS

ATTR patients (wild-type, hereditary and asymptomatic transthyretin [TTR] variant carriers) who had undergone ^99mTc-DPD and transthoracic echocardiogram (TTE) were selected. Quantitative ^99mTc-DPD uptake analysis and echocardiographic evaluation of LA structural and functional parameters was performed.

RESULTS

Forty (40) ATTR patients (wild-type n=17; hereditary ATTR and TTR variant carriers n=23; median age 68.8±22 years) were included. TTE parameters including indexed LA minimum (LAV_min) (r=0.66), and LA maximum volumes (LAV_max) (r=0.64), LA emptying fraction (LAEF) (r=-0.68), LA function index (LAFI) (r=-0.70) and reservoir strain (ƐR) (r=-0.70) (p<0.001 for all) demonstrated good correlation to LA tracer uptake. Normal LA volume (LAV_min and LAV_max) and function (LAEF, LAFI and ƐR) was observed in hereditary ATTR and TTR variant carriers without cardiac tracer uptake. The subgroup of ATTR patients with atrial fibrillation/flutter demonstrated increased LAV_min and LAV_max with further reduction in LA function (LAEF, LAFI and ƐR). Receiver operating characteristic curves demonstrated strong diagnostic accuracies for LA structural (LAV_min and LAV_max; area under the curve [AUC] of 0.83 and 0.84 respectively) and functional (LAEF, LAFI and ƐR; AUC 0.81, 0.88 and 0.85, respectively) parameters.

CONCLUSION

Left atrial structural and functional parameters demonstrated good correlations with quantitative ^99mTc-DPD tracer LA uptake. Echocardiography and ^99mTc-DPD scintigraphy may have significant roles in identification and surveillance of ATTR patients likely to develop atrial arrhythmias.

Transthyretin Amyloid Cardiomyopathy: Impact of Transthyretin Amyloid Deposition in Myocardium on Cardiac Morphology and Function

Background: Transthyretin (TTR) amyloid cardiomyopathy (ATTR-CM) is increasingly being recognized as a cause of left ventricular (LV) hypertrophy (LVH) and progressive heart failure in elderly patients. However, little is known about the cardiac morphology of ATTR-CM and the association between the degree of TTR amyloid deposition and cardiac dysfunction in these patients. Methods: We studied 28 consecutive patients with ATTR-CM and analyzed the relationship between echocardiographic parameters and pathological features using endomyocardial biopsy samples. Results: The cardiac geometries of patients with ATTR-CM were mainly classified as concentric LVH (96.4%). The relative wall thickness, a marker of LVH, tended to be positively correlated with the degree of non-cardiomyocyte area. The extent of TTR deposition was positively correlated with enlargement of the non-cardiomyocyte area, and these were positively correlated with LV diastolic dysfunction. Additionally, the extent of the area containing TTR was positively correlated with the percentage of cardiomyocyte nuclei stained for 8-hydroxy-2′deoxyguanosine, a marker of reactive oxygen species (ROS). ROS accumulation in cardiomyocytes was positively correlated with LV systolic dysfunction. Conclusion: Patients with ATTR-CM mainly displayed concentric LVH geometry. TTR amyloid deposition was associated with cardiac dysfunction via increased non-cardiomyocyte area and ROS accumulation in cardiomyocytes.

Clinical Phenotypes of Heart Failure With Preserved Ejection Fraction to Select Preclinical Animal Models

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To better define HFpEF clinically, patients are nowadays often clustered into phenogroups, based on their comorbidities and symptoms

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Many animal models claim to mimic HFpEF, but phenogroups are not yet regularly used to cluster them

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HFpEF animals models often lack reports of clinical symptoms of HF, therefore mainly presenting as extended models of LVDD, clinically seen as a prestate of HFpEF

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We investigated if clinically relevant phenogroups can guide selection of animal models aiming at better defined animal research

At least one-half of the growing heart failure population consists of heart failure with preserved ejection fraction (HFpEF). The limited therapeutic options, the complexity of the syndrome, and many related comorbidities emphasize the need for adequate experimental animal models to study the etiology of HFpEF, as well as its comorbidities and pathophysiological changes. The strengths and weaknesses of available animal models have been reviewed extensively with the general consensus that a “1-size-fits-all” model does not exist, because no uniform HFpEF patient exists. In fact, HFpEF patients have been categorized into HFpEF phenogroups based on comorbidities and symptoms. In this review, we therefore study which animal model is best suited to study the different phenogroups—to improve model selection and refinement of animal research. Based on the published data, we extrapolated human HFpEF phenogroups into 3 animal phenogroups (containing small and large animals) based on reports and definitions of the authors: animal models with high (cardiac) age (phenogroup aging); animal models focusing on hypertension and kidney dysfunction (phenogroup hypertension/kidney failure); and models with hypertension, obesity, and type 2 diabetes mellitus (phenogroup cardiometabolic syndrome). We subsequently evaluated characteristics of HFpEF, such as left ventricular diastolic dysfunction parameters, systemic inflammation, cardiac fibrosis, and sex-specificity in the different models. Finally, we scored these parameters concluded how to best apply these models. Based on our findings, we propose an easy-to-use classification for future animal research based on clinical phenogroups of interest.

Automatic Identification of Patients With Unexplained Left Ventricular Hypertrophy in Electronic Health Record Data to Improve Targeted Treatment and Family Screening

Background

Unexplained Left Ventricular Hypertrophy (ULVH) may be caused by genetic and non-genetic etiologies (e.g., sarcomere variants, cardiac amyloid, or Anderson-Fabry's disease). Identification of ULVH patients allows for early targeted treatment and family screening.

Aim

To automatically identify patients with ULVH in electronic health record (EHR) data using two computer methods: text-mining and machine learning (ML).

Methods

Adults with echocardiographic measurement of interventricular septum thickness (IVSt) were included. A text-mining algorithm was developed to identify patients with ULVH. An ML algorithm including a variety of clinical, ECG and echocardiographic data was trained and tested in an 80/20% split. Clinical diagnosis of ULVH was considered the gold standard. Misclassifications were reviewed by an experienced cardiologist. Sensitivity, specificity, positive, and negative likelihood ratios (LHR+ and LHR–) of both text-mining and ML were reported.

Results

In total, 26,954 subjects (median age 61 years, 55% male) were included. ULVH was diagnosed in 204/26,954 (0.8%) patients, of which 56 had amyloidosis and two Anderson-Fabry Disease. Text-mining flagged 8,192 patients with possible ULVH, of whom 159 were true positives (sensitivity, specificity, LHR+, and LHR– of 0.78, 0.67, 2.36, and 0.33). Machine learning resulted in a sensitivity, specificity, LHR+, and LHR– of 0.32, 0.99, 32, and 0.68, respectively. Pivotal variables included IVSt, systolic blood pressure, and age.

Conclusions

Automatic identification of patients with ULVH is possible with both Text-mining and ML. Text-mining may be a comprehensive scaffold but can be less specific than machine learning. Deployment of either method depends on existing infrastructures and clinical applications.