Multidisciplinary Approaches for Transthyretin Amyloidosis

Epidemiology, diagnosis, and management of cardiac amyloidosis

Cardiac amyloidosis (CA) is an infiltrative restrictive cardiomyopathy caused by the deposition of amyloid fibrils in the myocardium. It manifests in two primary subtypes: transthyretin cardiac amyloidosis (ATTR) and immunoglobulin light chain cardiac amyloidosis (AL). ATTR is further classified into wild-type and hereditary based on transthyretin gene mutation. Advances in diagnostics and therapeutics have transformed CA from a rare and untreatable condition to a more prevalent and manageable disease. Noninvasive diagnostic tools such as electrocardiography, echocardiography, and cardiac magnetic resonance can raise suspicion for CA; bone scintigraphy can non-invasively confirm ATTR, while AL necessitates histological confirmation. The severity of ATTR and AL can be assessed through serum biomarker-based staging. Treatment approaches differ, ranging from silencing or stabilizing transthyretin and degrading amyloid fibrils in ATTR to employing anti-plasma cell therapies and autologous stem cell transplantation in AL.

Preliminary efficacy and safety analysis of tafamidis in post-liver transplant patients with hereditary transthyretin cardiac amyloidosis

Hereditary transthyretin cardiac amyloidosis (ATTRv-CA) after liver transplantation remains challenging to treat due to residual amyloid deposits in extrahepatic organs, including the heart. Tafamidis, a transthyretin tetramer stabilizer, has shown promise in the treatment of ATTRv-CA; however, its efficacy and safety after liver transplantation are uncertain. In this preliminary retrospective review, we assessed the efficacy and safety of tafamidis (80 mg) in three ATTRv-CA cases after liver transplantation. Following one year of treatment, all patients experienced improvement in dyspnea, New York Heart Association functional class, brain natriuretic peptide levels, and cardiac troponin T levels. No significant changes in echocardiographic parameters were observed. Notably, no cardiovascular or drug-related adverse events occurred during treatment. Our findings suggest that tafamidis may benefit post-liver transplant patients with ATTRv-CA and warrant further investigation through randomized controlled trials with larger cohorts. This study highlights a potential therapeutic avenue for the management of cardiovascular involvement in this challenging patient population.

Clinical clues for suspecting wild-type transthyretin cardiac amyloidosis in patients with monoclonal gammopathy of undetermined significance: a case report

BACKGROUND

Myeloproliferative disorders, including monoclonal gammopathy of undetermined significance (MGUS), are often associated with amyloid light-chain (AL)-type cardiac amyloidosis (CA) but occasionally with wild-type transthyretin (ATTR) CA. In recent years, ATTR amyloidosis has attracted necessity for its reliable diagnosis with the addition of new treatments. Usually, both wild-type ATTR CA and AL-type CA present with marked cardiac hypertrophy, but renal dysfunction is milder in wild-type ATTR amyloidosis than in AL-type amyloidosis. Peripheral neurologic and autonomic symptoms such as numbness and dysesthesia are moderately present in AL-type amyloidosis, but less so in wild-type ATTR amyloidosis. Furthermore, the prognosis of ATTR-type amyloidosis is better than that of AL-type amyloidosis.

CASE PRESENTATION

A 72-year-old man with cardiac hypertrophy presented with New York Heart Association functional class III dyspnea and leg edema. He had no history of carpal tunnel syndrome. An electrocardiogram showed atrial fibrillation and low voltage. The N-terminal pro-B-type natriuretic peptide level was 3310 pg/mL, and troponin T was elevated to 0.073 ng/mL. However, the glomerular filtration rate was only slightly decreased at 69.0 mL/min/1.73 m2. The serum free light-chain assay revealed a significant increase in the kappa chain, with positive results in Bence Jones proteins and serum immunoelectrophoresis. Bone marrow examination confirmed the diagnosis of monoclonal gammopathy of undetermined significance (MGUS). AL-type amyloidosis associated with a myeloproliferative disorder was suspected, and the prognosis was initially predicted to be poor, classified as Mayo stage IV. Contrary to this prognosis, the patient showed a slow progression of heart failure. Further imaging modalities and cardiac tissue findings confirmed the diagnosis as transthyretin type amyloidosis, and a favorable prognosis was established with the use of tafamidis.

CONCLUSIONS

MGUS occasionally coexists with wild-type ATTR CA. Scant autonomic symptoms, mild renal dysfunction, and slow progression of heart failure might be clues that the CA associated with the myeloproliferative disease is wild-type ATTR amyloidosis.

Identification and management of gastrointestinal manifestations of hereditary transthyretin amyloidosis: Recommendations from an Italian group of experts

Gastrointestinal manifestations are common across all hereditary transthyretin amyloidosis (ATTRv) genotypes. However, they are poorly specific, and their recognition as part of ATTRv is difficult, resulting in misdiagnosis with more common conditions. Moreover, delays in diagnosis occur because of fragmented knowledge, a shortage of centers of excellence and specialists dedicated to ATTRv management, and the scarce involvement of gastroenterologists in multidisciplinary teams. A group of Italian gastroenterologists with experience in the management of ATTRv took part in a project aimed at assessing the awareness of ATTRv among the community of Italian gastroenterologists through an online survey and providing education about practical aspects of ATTRv management. Survey results reported low participation, and very few patients with ATTRv were cared for by gastroenterologists. This highlights the need for greater attention to rare diseases in gastroenterology and emphasizes increasing awareness of ATTRv and diagnostic suspicion. Based on the experts' recommendations, a diagnosis of ATTRv should be suspected when at least one of the 'red flags' is detected. Subsequently, it is suggested to promptly ask for genetic testing and exclude a serum and urinary monoclonal protein, even before the detection of amyloid in biopsy samples, particularly in non-endemic areas.

Case Report: A rare transthyretin mutation p.D58Y in a Chinese case of transthyretin amyloid cardiomyopathy

Hereditary transthyretin amyloid (ATTRv) cardiomyopathy (CM) is caused by mutations in the TTR gene. TTR mutations contribute to TTR tetramer destabilization and dissociation, leading to excessive deposition of insoluble amyloid fibrils in the myocardium and finally resulting in cardiac dysfunction. In this article, we report a case of a Chinese patient with transthyretin mutation p.D58Y and provide detailed information on cardiac amyloidosis, including transthoracic echocardiography, cardiac magnetic resonance, and SPECT imaging for the first time. Our report aims to provide a better understanding of ATTR genotypes and phenotypes.

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.

Serum Biomarkers and Their Association with Myocardial Function and Exercise Capacity in Cardiac Transthyretin Amyloidosis

BACKGROUND

Transthyretin cardiac amyloidosis (ATTR amyloidosis) is a frequent etiology of heart failure. Inflammation and mineral metabolism are associated with myocardial dysfunction and clinical performance. Cardiac global longitudinal strain (GLS) allows function assessment and is associated with prognosis. Our aim was to describe possible correlations between GLS, biomarker levels and clinical performance in ATTR amyloidosis.

METHODS

Thirteen patients with ATTR amyloidosis were included. Clinical characteristics; echocardiographic features, including strain assessment and 6 min walk test (6MWT); and baseline inflammatory, mineral metabolism and cardiovascular biomarker levels were assessed.

RESULTS

Of the 13 patients, 46.2% were women, and the mean age was 79 years. TAPSE correlated with NT-ProBNP (r -0.65, p < 0.05) and galectin-3 (r 0.76, p < 0.05); E/E' ratio correlated with hsCRP (r 0.58, p < 0.05). Left ventricular GLS was associated with NT-ProBNP (r 0.61, p < 0.05) (patients have a better prognosis if the strain value is more negative) and left atrial GLS with NT-ProBNP (r -0.73, p < 0.05) and MCP1 (r 0.55, p < 0.05). Right ventricular GLS was correlated with hsTnI (r 0.62, p < 0.05) and IL6 (r 0.881, p < 0.05). Klotho levels were correlated with 6MWT (r 0.57, p < 0.05).

CONCLUSIONS

While inflammatory biomarkers were correlated with cardiac function, klotho levels were associated with clinical performance in the population with TTR-CA.

Prevalence of transthyretin amyloid cardiomyopathy in patients admitted for acute heart failure

INTRODUCTION

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underdiagnosed cause of AHF that benefits from a specific approach. The aim was to determine the prevalence of ATTR-CM among patients hospitalized for AHF.

METHODS

A prospective study was conducted on consecutive patients aged 60 or older admitted for acute AHF without cardiogenic shock.

RESULTS

The study included 103 patients, a total of 16 patients (15.5 %) were compatible with ATTR-CM. The ATTR-CM group showed a higher septal wall thickness (18.1 mm vs. 11.8 mm; P = 0.001), lower systolic excursion of the tricuspid annular plane (15 mm vs. 18.3 mm, P = 0.014), and S wave of the right ventricle (8 cm/s vs. 9.2 cm/s P=0.032).

CONCLUSION

ATTR-CM is an underdiagnosed condition, there are some variables associated with its diagnosis. The coexistence with other comorbidities causing AHF, highlights the importance of considering screening for this cardiomyopathy in adults hospitalized for AHF.

Isolated Valve Amyloid Deposition in Aortic Stenosis: Potential Clinical and Pathophysiological Relevance

Amyloid deposition within stenotic aortic valves (AVs) also appears frequent in the absence of cardiac amyloidosis, but its clinical and pathophysiological relevance has not been investigated. We will elucidate the rate of isolated AV amyloid deposition and its potential clinical and pathophysiological significance in aortic stenosis (AS). In 130 patients without systemic and/or cardiac amyloidosis, we collected the explanted AVs during cardiac surgery: 57 patients with calcific AS and 73 patients with AV insufficiency (41 with AV sclerosis and 32 without, who were used as controls). Amyloid deposition was found in 21 AS valves (37%), 4 sclerotic AVs (10%), and none of the controls. Patients with and without isolated AV amyloid deposition had similar clinical and echocardiographic characteristics and survival rates. Isolated AV amyloid deposition was associated with higher degrees of AV fibrosis (p = 0.0082) and calcification (p < 0.0001). Immunohistochemistry analysis suggested serum amyloid A1 (SAA1), in addition to transthyretin (TTR), as the protein possibly involved in AV amyloid deposition. Circulating SAA1 levels were within the normal range in all groups, and no difference was observed in AS patients with and without AV amyloid deposition. In vitro, AV interstitial cells (VICs) were stimulated with interleukin (IL)-1β which induced increased SAA1-mRNA both in the control VICs (+6.4 ± 0.5, p = 0.02) and the AS VICs (+7.6 ± 0.5, p = 0.008). In conclusion, isolated AV amyloid deposition is frequent in the context of AS, but it does not appear to have potential clinical relevance. Conversely, amyloid deposition within AV leaflets, probably promoted by local inflammation, could play a role in AS pathophysiology.

Cardiac Amyloidosis: A Contemporary Review of Medical and Surgical Therapy

Amyloidosis is a systemic disease initiated by deposition of misfolded proteins in the extracellular space, due to which multiple organs may be affected concomitantly. Cardiac amyloidosis, however, remains a major cause of morbidity and mortality in this population due to infiltrative /restrictive cardiomyopathy. This review attempts to focus on contemporary medical and surgical therapies for the different types of cardiac amyloidosis. Amyloidosis affecting the heart are predominantly of the transthyretin type (acquired in the older or genetic in the younger patients), and the monoclonal immunoglobulin light chain (AL) type which is solely acquired. A rare form of secondary amyloidosis AA type can also affect the heart due to excessive production and accumulation of the acute-phase protein called Serum Amyloid A" (SAA) in the setting of chronic inflammation, cancers or autoinflammatory disease. More commonly AA amyloidosis is seen in the liver and kidney. Other rare types are Apo A1 and Isolated Atrial Amyloidosis (AANF). Medical therapies have made important strides in the clinical management of the two common types of cardiac amyloidosis. Surgical therapies such as mechanical circulatory support and cardiac transplantation should be considered in appropriate patients. Future research using AI driven algorithms for early diagnosis and treatment as well as development of newer genetic engineering technologies will drive improvements in diagnosis, treatment and patient outcomes.

Interdisciplinary Multidimensional Assessment of Transthyretin Amyloidosis before and after Tafamidis

BACKGROUND

Clinically, there is considerable heterogeneity in the presentation of transthyretin amyloidosis (ATTR), which ranges from primarily cardiac and primarily neurologic to mixed disease, among other manifestations. Because of this complex presentation, the diagnosis and management of patients with ATTR are often challenging and should be performed in interdisciplinary centers specialized in amyloidosis. Here, we aimed to increase awareness of ATTR detection and pathophysiology through a multidimensional multiorgan approach.

CASE REPORT

We reported on a 60-year-old man with wild-type ATTR who underwent a number of both basic and advanced cardiological and neurological investigations at baseline and after a treatment period with the TTR tetramer stabilizer, tafamidis. Several findings are provided here, some of which might be considered instrumental correlates of the patient's clinical improvement after therapy.

CONCLUSIONS

Adequate awareness and prompt recognition of ATTR support early diagnosis and faster access to therapies, thereby slowing the progression and improving the prognosis. The need for a multidisciplinary alliance between specialists and the opportunity to perform, at least in selected cases, a set of specific examinations for a detailed assessment of ATTR patients can also provide valuable insights into the physiopathology and response to therapy of a disease as complex and intriguing as ATTR.

World Heart Federation Consensus on Transthyretin Amyloidosis Cardiomyopathy (ATTR-CM)

Transthyretin amyloid cardiomyopathy (ATTR-CM) is a progressive and fatal condition that requires early diagnosis, management, and specific treatment. The availability of new disease-modifying therapies has made successful treatment a reality. Transthyretin amyloid cardiomyopathy can be either age-related (wild-type form) or caused by mutations in the TTR gene (genetic, hereditary forms). It is a systemic disease, and while the genetic forms may exhibit a variety of symptoms, a predominant cardiac phenotype is often present. This document aims to provide an overview of ATTR-CM amyloidosis focusing on cardiac involvement, which is the most critical factor for prognosis. It will discuss the available tools for early diagnosis and patient management, given that specific treatments are more effective in the early stages of the disease, and will highlight the importance of a multidisciplinary approach and of specialized amyloidosis centres. To accomplish these goals, the World Heart Federation assembled a panel of 18 expert clinicians specialized in TTR amyloidosis from 13 countries, along with a representative from the Amyloidosis Alliance, a patient advocacy group. This document is based on a review of published literature, expert opinions, registries data, patients' perspectives, treatment options, and ongoing developments, as well as the progress made possible via the existence of centres of excellence. From the patients' perspective, increasing disease awareness is crucial to achieving an early and accurate diagnosis. Patients also seek to receive care at specialized amyloidosis centres and be fully informed about their treatment and prognosis.

Patisiran for the Treatment of Transthyretin-mediated Amyloidosis with Cardiomyopathy

Transthyretin (TTR) is a tetrameric protein, synthesized primarily by the liver, that acts as a physiological transport protein for retinol and thyroxine. TTR can misfold into pathogenic amyloid fibrils that deposit in the heart and nerves, causing a life-threatening transthyretin amyloidosis cardiomyopathy (ATTR-CM), and a progressive and debilitating polyneuropathy (ATTR-PN). Recent therapeutic advances have resulted in the development of drugs that reduce TTR production. Patisiran is a small interfering RNA that disrupts the complimentary mRNA and inhibits TTR synthesis, and is the first gene-silencing medication licensed for the treatment of ATTR amyloidosis. After encouraging results following the use of patisiran for the treatment of patients with ATTR-PN, there has been increasing interest in the use of patisiran for the treatment of ATTR-CM. Various studies have demonstrated improvements across a wide range of cardiac biomarkers following treatment with patisiran, and have changed the perception of ATTR-CM from being thought of as a terminal disease process, to now being regarded as a treatable disease. These successes represent a huge milestone and have the potential to revolutionize the landscape of treatment for ATTR-CM. However, the long-term safety of patisiran and how best to monitor cardiac response to treatment remain to be determined.

Clinical characteristics and health care resource use of patients at risk for wild-type transthyretin amyloid cardiomyopathy identified by machine learning model

BACKGROUND: Transthyretin amyloid cardiomyopathy (ATTR-CM) is a progressive, life-threatening systemic disorder that is an underrecognized cause of heart failure (HF). When the diagnosis of wild-type ATTR-CM (ATTRwt-CM) is delayed, patients often undergo additional assessments, deferring appropriate management as symptoms potentially worsen. Prompt recognition of patients at risk for ATTRwt-CM is essential to facilitate earlier diagnosis and disease-modifying treatment. A previously developed machine learning model performed well in identifying ATTRwt-CM in patients with HF vs controls with nonamyloid HF using medical claims/electronic health records, providing a systematic framework to raise disease suspicion. OBJECTIVE: To further evaluate this model's performance in identifying ATTRwt-CM using a large claims database of older adults with HF and confirmed ATTRwt-CM or nonamyloid HF; and to explore the characteristics and health care resource utilization (HCRU) of patients with confirmed and suspected ATTRwt-CM. METHODS: In this retrospective study, the prior model was applied using Humana administrative claims for patients diagnosed with ATTRwt-CM (cases) and nonamyloid HF (controls [1:1]). Patients were aged 65-89 years, had at least 2 claims for HF diagnosis (2015-2020), and were continuously enrolled in a Medicare Advantage prescription drug plan for at least 12 months before and at least 6 months after HF diagnosis. For the assessment of characteristics and HCRU, the suspected risk level was categorized based on the predicted probability (PP) from model output (high, moderate, and low risk: PP≥0.70; ≥0.50 and < 0.70; and < 0.50, respectively). RESULTS: Of 267,025 eligible patients, 119 (0.04%) had confirmed ATTRwt-CM; of 266,906 patients with nonamyloid HF, 10,997 (4.1%), 68,174 (25.5%), and 187,735 (70.3%) were categorized as high, moderate, and low risk for ATTRwt-CM, respectively. The model demonstrated sensitivity/specificity/accuracy/receiver operating characteristic area under the concentration-time curve of 88%/65%/77%/0.89, respectively, in differentiating ATTRwt-CM from nonamyloid HF. In patients with confirmed ATTRwt-CM, the mean (SD) time between HF and ATTRwt-CM diagnoses was 751 (528) days; 65% and 48% were hospitalized before and after ATTRwt-CM diagnosis, respectively. Atrial fibrillation was more common in patients with confirmed ATTRwt-CM and high risk (39% and 55%) vs low risk (27%). Hospitalization and emergency department visits after HF diagnosis were reported in 57% and 46% of patients with high ATTRwt-CM risk, respectively. CONCLUSIONS: The ATTRwt-CM predictive model performed well in identifying disease risk in the Humana Research Database. Patients at high risk for ATTRwt-CM had high HCRU and may benefit from the earlier suspicion of ATTRwt-CM. The model may be used as a tool to identify patients with a suspected high risk for the disease to facilitate earlier detection and treatment. DISCLOSURES: This study was sponsored by Pfizer. Medical writing support was provided by Donna McGuire of Engage Scientific Solutions and funded by Pfizer. Drs Bruno and Schepart and Mr Casey are currently employees of Pfizer and equity holders in this publicly traded company. Dr Reed was an employee of Pfizer at the time that this analysis was planned and conducted. Mr Sheer and Dr Simmons are currently employees of Humana, which received research funding from Pfizer. Dr Nair was an employee of Humana at the time that this analysis was planned and conducted.

Cardiac amyloidosis presenting as pulmonary arterial hypertension: A case report

BACKGROUND

Pulmonary hypertension is a rare cardiopulmonary disease, with an insidious onset that usually worsens rapidly. Amyloid light chain (AL) amyloidosis is a rare systemic disease caused by extracellular deposition of pathologic, insoluble, and proteinaceous fibrils in organs and tissues; however, it is difficult to diagnose given its varied and nonspecific symptoms. To date, rare cases of amyloidosis with pulmonary hypertension have been reported. Of note, the optimal treatments for cardiac amyloidosis complicated with pulmonary hypertension remain unclear.

CASE SUMMARY

We report a case of a 51-year-old woman who presented with progressively worsening dyspnea. Transthoracic echocardiography indicated severe pulmonary hypertension. Twenty-seven months after first admission, the patient returned with symptoms of progressive heart failure. A myocardial tissue sample stained with Congo red was positive, and the patient was ultimately diagnosed with AL amyloidosis with cardiac involvement.

CONCLUSION

Although pulmonary hypertension may be idiopathic, it is frequently associated with other conditions. In rare cases, pulmonary hypertension can be a complication of AL amyloidosis, which should be seriously considered in any adult presenting with nonspecific signs or symptoms of cardiac distress.

Treatment of acquired transthyretin amyloidosis in domino liver transplantation

BACKGROUND

Domino liver transplantation (DLT) has been commonly used during the last two decades to partly meet the high need for liver transplants. However, the recipients of grafts from patients with noncirrhotic inherited metabolic disorders may ultimately develop metabolic syndrome, and management is usually intricate, being complicated by the underlying initial disorder, other comorbidities, and post-transplantation conditions.

CASE

We report here the management and the outcome in a patient with acquired transthyretin amyloidosis after DLT and significant comorbidities. Final treatment with a transthyretin gene silencing agent, patisiran, was well tolerated and resulted in remission of the aggravating neurological deficits in a follow-up period of 2 years.

CONCLUSIONS

The case presented here supports the concept that patisiran can target the hepatocytes producing the mutated transthyretin in acquired transthyretin amyloidosis, as efficiently as in hereditary transthyretin amyloidosis (hATTR), and can be used to treat patients with transthyretin amyloidosis after DLT.

A review of recent advances in the diagnosis of cardiac amyloidosis, treatment of its cardiac complications, and disease-modifying therapies

Cardiac amyloidosis (CA), a significant condition resulting in infiltrative cardiomyopathy and heart failure with preserved ejection fraction (HFpEF), is caused by extracellular deposition of amyloid fibrils in the heart. Even though this has been known for an extended period, its prevalence in elderly patients with heart failure is increasingly being recognized. Recent advances in diagnosis with non-invasive methods like technetium pyrophosphate-labeled cardiac scintigraphy (i.e., Tc-PYP scan) and treatment options with tafamidis have played a pivotal role in awareness of the burden of this disease. Management of cardiac complications like heart failure, atrial arrhythmias, conduction block, ventricular arrhythmias, coronary artery disease, and aortic stenosis is now more critical than ever. We aim to review and outline the recent advances in diagnoses of CA. We also review management strategies for cardiac complications of CA with a brief summary of disease-modifying therapies.

Recent Advances in Cardiovascular Diseases Research Using Animal Models and PET Radioisotope Tracers

Cardiovascular diseases (CVD) is a collective term describing a range of conditions that affect the heart and blood vessels. Due to the varied nature of the disorders, distinguishing between their causes and monitoring their progress is crucial for finding an effective treatment. Molecular imaging enables non-invasive visualisation and quantification of biological pathways, even at the molecular and subcellular levels, what is essential for understanding the causes and development of CVD. Positron emission tomography imaging is so far recognized as the best method for in vivo studies of the CVD related phenomena. The imaging is based on the use of radioisotope-labelled markers, which have been successfully used in both pre-clinical research and clinical studies. Current research on CVD with the use of such radioconjugates constantly increases our knowledge and understanding of the causes, and brings us closer to effective monitoring and treatment. This review outlines recent advances in the use of the so-far available radioisotope markers in the research on cardiovascular diseases in rodent models, points out the problems and provides a perspective for future applications of PET imaging in CVD studies.

Changing paradigm in the treatment of amyloidosis: From disease-modifying drugs to anti-fibril therapy

Cardiac amyloidosis is a rare, debilitating, and usually fatal disease increasingly recognized in clinical practice despite patients presenting with non-specific symptoms of cardiomyopathy. The current standard of care (SoC) focuses on preventing further amyloid formation and deposition, either with anti-plasma cell dyscrasia (anti-PCD) therapies in light-chain (AL) amyloidosis or stabilizers of transthyretin (TTR) in transthyretin amyloidosis (ATTR). The SoC is supplemented by therapies to treat the complications arising from organ dysfunction; for example, heart failure, arrhythmia, and proteinuria. Advancements in treatments have improved patient survival, especially for those whose disease is detected and for whom treatment is initiated at an early stage. However, there still are many unmet medical needs, particularly for patients with severe disease for whom morbidity and mortality remain high. There currently are no approved treatments to reverse amyloid infiltration and deplete the amyloid fibrils already deposited in organs, which can continue to cause progressive dysfunction. Anti-fibril therapies aimed at removing the deposited fibrils are being investigated for safety and efficacy in improving outcomes for patients with severe disease. However, there is no clinical evidence yet that removing deposited amyloid fibrils will improve organ function, thereby improving quality of life or extending life. Nevertheless, anti-fibril therapies are actively being investigated in clinical trials to evaluate their ability to complement and synergize with current SoC.

Multimodality assessments of wild‐type transthyretin cardiac amyloidosis with no ventricular hypertrophy

While patients with transthyretin cardiac amyloidosis (ATTR-CA) typically present with concentric or asymmetric hypertrophy, a small percentage of ATTR-CA is known to present with 'atypical' cardiac morphologies such as eccentric hypertrophy or even no hypertrophy. However, detailed report of multimodality assessments of ATTR-CA with no ventricular hypertrophy is lacking. Herein, we report detailed multimodality assessments of an 81-year-old Japanese woman with heart failure and history of carpal tunnel syndrome and lumbar canal stenosis, presenting no ventricular hypertrophy and negative ^99m technetium-pyrophosphate scintigraphy, who was eventually diagnosed as having wild-type ATTR-CA. Our case highlights the role of multimodality assessments for early diagnosis of ATTR-CA in patients with atypical cardiac morphologies and also emphasizes the limitations of bone scintigraphy and the importance of considering ATTR-CA in patients with non-cardiac manifestations of ATTR amyloidosis.

Cardiomyopathy correlates to nerve damage in p.A117S late-onset transthyretin amyloid polyneuropathy

Objective

Late‐onset hereditary transthyretin amyloidosis with polyneuropathy (ATTRv‐PN) is often associated with heart involvement. Recent advances in cardiac imaging allow the detection of cardiac amyloidosis. This study aimed to explore cardiomyopathy by cardiac imaging and its clinical correlates with polyneuropathy in late‐onset ATTRv‐PN.

Methods

Polyneuropathy was assessed by intraepidermal nerve fiber (IENF) density, nerve conduction study (NCS), autonomic function tests, quantitative sensory testing, and clinical questionnaires. Cardiomyopathy was evaluated by echocardiography, ^99mTc‐pyrophosphate (PYP) single‐photon emission computed tomography (SPECT) imaging, cardiac magnetic resonance imaging (CMR), and serum Pro‐B‐type natriuretic peptide. Healthy controls and patients with Brugada syndrome were enrolled for comparison of CMR.

Results

Fifty late‐onset ATTRv‐PN patients (38 men, 46 with p. A117S mutation), aged 63.7 ± 5.5 years, of polyneuropathy disability stage 1–4 were enrolled. All patients presented polyneuropathy in NCS, and 74.5% of patients had reduced IENF density in distal legs. All patients showed significant radiotracer uptake in the heart on ^99mTc‐PYP SPECT imaging, and 87.8% of patients had abnormally increased left ventricular (LV) septum thickness on echocardiography. CMR showed longer myocardial native T1, larger extracellular volume, greater LV mass index, and higher LV mass to end‐diastolic volume ratio in ATTRv‐PN patients than healthy controls and patients with Brugada syndrome. These CMR parameters were associated with skin denervation, absent sympathetic skin responses, elevated thermal thresholds, worsened NCS profiles, and functional deficits of polyneuropathy.

Interpretation

Late‐onset ATTRv‐PN coexisted with cardiomyopathy regardless of the clinical severity of polyneuropathy. The cardiac amyloid burden revealed by CMR was correlated with pathophysiology and clinical disability of nerve degeneration.

Clinical Profile and Prognosis of Hereditary Transthyretin Amyloid Cardiomyopathy: A Single-Center Study in South China

Background

Hereditary transthyretin amyloid cardiomyopathy (ATTR-CM) is a genotypically heterogeneous disorder with a poor prognosis. There is limited literature describing the variants responsible for ATTRv in areas outside the United State, the United Kingdom and Europe. This study was performed to describe the clinical characteristics and genotypic profiles of this disease in South China.

Methods

This was a single-center retrospective study that evaluated 29 patients with a confirmed diagnosis of hereditary transthyretin amyloid cardiomyopathy enrolled from January 2016 to November 2021.

Results

93.1% patients were male and the median age of symptom onset was 53 (46, 62.5) years old. The initial manifestations of ATTR-CM were cardiovascular symptoms (55.2%), neuropathy (41.4%) and vitreous opacity (3.4%). Phenotypes at diagnosis were mixed (82.8%), predominant cardiac (6.9%), neurological (6.9%) and ophthalmic (3.4%). Poor R-wave progression (41%), pseudo-infarct (31%) and low-voltage (31%) patterns were common findings on electrocardiogram. Unexplained increased wall thickness was observed in all 29 patients, with mean septal and posterior wall thicknesses of 14.25 ± 6.26 mm and 15.34 ± 2.84 mm, respectively. Diastolic dysfunction was also seen in all 29 patients, and 17 (58%) had a restrictive fill pattern at diagnosis. Nine different missense mutations of the TTR gene were found in 29 patients from 23 families, with c.349G>T (p.Ala117Ser) the most common mutation. The median survival time after diagnosis was 47.6 (95% CI 37.9-57.4) months, with 1, 3 and 5-year survival rates of 91.2%, 74% and 38% respectively. Patients with advanced heart failure (National Amyloidosis Staging stage II/III) had worse survival than stage I [Breslow (Generalized Wilcoxon), χ2 = 4.693, P = 0.03)].

Conclusions

ATTR amyloidosis genotypes and phenotypes are highly heterogeneous. Advanced heart failure predicts a poor prognosis. Understanding the different clinical profiles of ATTR cardiac amyloidosis with different genotype is important to its early recognition.

Re-Definition of the Epidemiology of Cardiac Amyloidosis

The epidemiology of cardiac amyloidosis (CA), traditionally considered a rare and incurable disease, has changed drastically over the last ten years, particularly due to the advances in diagnostic methods and therapeutic options in the field of transthyretin CA (ATTR-CA). On the one hand, the possibility of employing cardiac scintigraphy with bone tracers to diagnose ATTR-CA without a biopsy has unveiled the real prevalence of the disease; on the other, the emergence of effective treatments, such as tafamidis, has rendered an early and accurate diagnosis critical. Interestingly, the following subgroups of patients have been found to have a higher prevalence of CA: elderly subjects > 75 years, patients with cardiac hypertrophy hospitalized for heart failure with preserved ejection fraction, subjects operated on for bilateral carpal tunnel syndrome, patients with cardiac hypertrophy not explained by concomitant factors and individuals with aortic valve stenosis. Many studies investigating the prevalence of CA in these particular populations have contributed to rewriting the epidemiology of the disease, increasing the awareness of the medical community for a previously underappreciated condition. In this review, we summarized the latest evidence on the epidemiology of CA according to the different clinical settings typically associated with the disease.

Clinical and genetic profile of patients enrolled in the Transthyretin Amyloidosis Outcomes Survey (THAOS): 14-year update

BACKGROUND

Transthyretin amyloidosis (ATTR amyloidosis) is a rare, life-threatening disease caused by the accumulation of variant or wild-type (ATTRwt amyloidosis) transthyretin amyloid fibrils in the heart, peripheral nerves, and other tissues and organs.

METHODS

Established in 2007, the Transthyretin Amyloidosis Outcomes Survey (THAOS) is the largest ongoing, global, longitudinal observational study of patients with ATTR amyloidosis, including both inherited and wild-type disease, and asymptomatic carriers of pathogenic TTR mutations. This descriptive analysis examines baseline characteristics of symptomatic patients and asymptomatic gene carriers enrolled in THAOS since its inception in 2007 (data cutoff: August 1, 2021).

RESULTS

This analysis included 3779 symptomatic patients and 1830 asymptomatic gene carriers. Symptomatic patients were predominantly male (71.4%) and had a mean (standard deviation [SD]) age of symptom onset of 56.3 (17.8) years. Val30Met was the most common genotype in symptomatic patients in South America (80.9%), Europe (55.4%), and Asia (50.5%), and more patients had early- versus late-onset disease in these regions. The majority of symptomatic patients in North America (58.8%) had ATTRwt amyloidosis. The overall distribution of phenotypes in symptomatic patients was predominantly cardiac (40.7%), predominantly neurologic (40.1%), mixed (16.6%), and no phenotype (2.5%). In asymptomatic gene carriers, mean (SD) age at enrollment was 42.4 (15.7) years, 42.4% were male, and 73.2% carried the Val30Met mutation.

CONCLUSIONS

This 14-year global overview of THAOS in over 5000 patients represents the largest analysis of ATTR amyloidosis to date and highlights the genotypic and phenotypic heterogeneity of the disease.

CLINICALTRIALS

gov Identifier: NCT00628745.

Italian Real-Life Experience of Patients with Hereditary Transthyretin Amyloidosis Treated with Patisiran

Hereditary transthyretin amyloidosis (ATTRv) is a multisystemic, rare, inherited, progressive and adult-onset disease, affecting the sensorimotor nerves, heart, autonomic function and other organs. The actual scenario of pharmaceutical approaches for ATTRv amyloidosis includes five main groups: TTR stabilizers, TTR mRNA silencers, TTR fibril disruptors, inhibitor of TTR fibril seeding and gene therapy. Patisiran is a small, double-stranded interfering RNA encapsulated in a lipid nanoparticle, able to penetrate into hepatocytes, where it selectively targets TTR mRNA, reducing TTR production. We report and discuss 9 cases of different patients with ATTRv amyloidosis successfully managed with patisiran in the real clinical practice. Literature data, as well as the above presented case reports, show that this drug is effective and safe in improving both neurological and cardiovascular symptoms of ATTRv amyloidosis, and to maintain a good QoL, independently form the stage of the disease and the involved mutation. Recent studies correlated improved functional and biochemical outcomes with a regression of amyloid burden, especially at the cardiac level. Today, patisiran can be considered a valid therapeutic option for the management of patients with ATTRv amyloidosis and polyneuropathy and cardiovascular symptoms.

Healthcare resource use associated with the diagnosis of transthyretin amyloidosis cardiomyopathy

OBJECTIVES

Our primary aim was to evaluate the healthcare resource use associated with the diagnosis of transthyretin amyloidosis cardiomyopathy. Second, we aim to assess the effect of the number of diagnostic tests and clinical contact points on the total time and costs between symptom onset and diagnosis defining a quantitative hypothetical optimized diagnostic pathway.

SETTING

Clinical and cost data were collected from patients presenting between 2010 and 2018 in a tertiary referral institution in South London involving two participating hospitals.

PARTICIPANTS

Thirty-eight adult patients with a definite diagnosis of transthyretin amyloidosis cardiomyopathy were included, mostly male (n = 28, 74%) and of African-Caribbean descent (n = 23, 64%). We excluded patients without a confirmed transthyretin amyloidosis cardiomyopathy or those on inotersen, patisiran, or diflunisal at point of referral.

PRIMARY AND SECONDARY OUTCOME MEASURES

The average time between first presentation and final diagnosis, and the cost per patient per month. By comparing to a more optimal clinical pathway towards diagnosis, we considered what could be the theoretical gain in terms of time to diagnosis and financial savings.

RESULTS

The average time between first presentation and final diagnosis was 2.74 years. The average cost per patient per month was higher with progressive heart failure symptoms. A hypothetical optimal pathway reduces time to diagnosis of 1.65 to 1.74 years per patient. The potential financial savings are estimated within the range of £3000 to £4800 per patient.

CONCLUSIONS

Patients diagnosed with transthyretin amyloidosis cardiomyopathy have substantial healthcare resource utilization and costs starting from symptom onset. Higher costs were observed with progression in symptoms and appear linked to a delayed diagnosis. The number of additional diagnostic tests and clinical contact points may contribute to this and could represent a path to explore further for important health and cost savings, with more efficient pathways for these patients to be managed.

Applying diagnosis support systems in electronic health records to identify wild-type transthyretin amyloid cardiomyopathy risk

Aim: Wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM) is frequently misdiagnosed, and delayed diagnosis is associated with substantial morbidity and mortality. At three large academic medical centers, combinations of phenotypic features were implemented in electronic health record (EHR) systems to identify patients with heart failure at risk for ATTRwt-CM. Methods: Phenotypes/phenotype combinations were selected based on strength of correlation with ATTRwt-CM versus non-amyloid heart failure; different clinical decision support and reporting approaches and data sources were evaluated on Cerner and Epic EHR platforms. Results: Multiple approaches/sources showed potential usefulness for incorporating predictive analytics into the EHR to identify at-risk patients. Conclusion: These preliminary findings may guide other medical centers in building and implementing similar systems to improve recognition of ATTRwt-CM in patients with heart failure.

Elderly patients with suspected Charcot-Marie-Tooth disease should be tested for the TTR gene for effective treatments

BACKGROUND AND AIMS

Some hereditary transthyretin (ATTRv) amyloidosis patients are misdiagnosed as Charcot-Marie-Tooth disease (CMT) at onset. We assess the findings to identify ATTRv amyloidosis among patients with suspected CMT to screen transthyretin gene variants for treatments.

METHODS

We assessed clinical, cerebrospinal fluid, and electrophysiological findings by comparing ATTRv amyloidosis patients with suspected CMT (n = 10) and CMT patients (n = 489).

RESULTS

The median (interquartile range) age at onset of neurological symptoms was 69 (64.2-70) years in the ATTRv amyloidosis vs 12 (5-37.2) years in CMT group (Mann-Whitney U, p < 0.01). The proportion of patients with initial sensory symptoms was 70% in the ATTRv amyloidosis group vs 7.1% in CMT group (Fisher's exact, p < 0.01). The proportion of patients with histories of suspected chronic inflammatory demyelinating polyneuropathy (CIDP) were 50% in the ATTRv amyloidosis group vs 8.7% in CMT group (Fisher's exact, p < .01). Other measures and outcomes were not different between the two groups. Five of the six patients with ATTRv amyloidosis received treatment and survived.

INTERPRETATION

For effective treatments, the transthyretin gene should be screened in patients with suspected CMT with old age at onset of neurological symptoms, initial sensory symptoms, and histories of suspected CIDP.

Antibody-Based Affinity Capture Combined with LC-MS Analysis for Identification of COVID-19 Disease Serum Biomarkers

Blood serum or plasma proteins are potentially useful in COVID-19 research as biomarkers for risk prediction, diagnosis, stratification, and treatment monitoring. However, serum protein-based biomarker identification and validation is complicated due to the wide concentration range of these proteins, which spans more than ten orders of magnitude. Here we present a combined affinity purification-liquid chromatography mass spectrometry approach which allows identification and quantitation of the most abundant serum proteins along with the nonspecifically bound and interaction proteins. This led to the reproducible identification of more than 100 proteins that were not specifically targeted by the affinity column. Many of these have already been implicated in COVID-19 disease.

Enhancing knowledge and awareness of transthyretin cardiac amyloidosis and shared decision-making among cardiology team members in Colorado, USA via an online educational initiative

OBJECTIVES

Our project aimed to increase knowledge of noninvasive diagnostic modalities (including bone radiotracer scintigraphy), raise suspicion of transthyretin cardiac amyloidosis (ATTR-CA), and improve cardiology team member's awareness and knowledge of shared decision-making (SDM), as well as the quality of SDM communication between cardiology team members and patients.

METHODS

An online educational module and survey was developed and cardiology team members in Colorado, USA, were invited to participate. This online educational module included various important topics related to ATTR-CA (e.g., the cause of ATTR-CA, endomyocardial biopsy, and noninvasive methods to diagnose ATTR-CA) and SDM (e.g., benefits of SDM, the role of SDM in the diagnosis of ATTR-CA, implementation of SDM in cardiology practice, and the 3-talk model).

RESULTS

There were 34 survey respondents, over one-third of whom were cardiologists. Most respondents agreed on the importance of diagnosing ATTR-CA at an early stage, and about three-quarters of the survey takers agreed that bone scintigraphy can reliably diagnose ATTR-CA without the need for endomyocardial biopsy. Concern over increased time commitment was the leading barrier to the implementation of SDM in respondents' clinical practice. The majority of respondents identified the correct answer regarding ATTR-CA and SDM after reading the online educational module. This improvement in scores after exposure to the online educational module was statistically significant.

CONCLUSION

Baseline knowledge and awareness of various issues related to ATTR-CA was relatively low among cardiology team members. Participants' knowledge was enhanced through our effective online educational program. Prospective educational projects focused on various methods of detecting ATTR-CA as well as other amyloid conditions in diverse clinical settings will remain important.

Significance of Oligomeric and Fibrillar Species in Amyloidosis: Insights into Pathophysiology and Treatment

Amyloidosis is a term referring to a group of various protein-misfolding diseases wherein normally soluble proteins form aggregates as insoluble amyloid fibrils. How, or whether, amyloid fibrils contribute to tissue damage in amyloidosis has been the topic of debate. In vitro studies have demonstrated the appearance of small globular oligomeric species during the incubation of amyloid beta peptide (Aβ). Nerve biopsy specimens from patients with systemic amyloidosis have suggested that globular structures similar to Aβ oligomers were generated from amorphous electron-dense materials and later developed into mature amyloid fibrils. Schwann cells adjacent to amyloid fibrils become atrophic and degenerative, suggesting that the direct tissue damage induced by amyloid fibrils plays an important role in systemic amyloidosis. In contrast, there is increasing evidence that oligomers, rather than amyloid fibrils, are responsible for cell death in neurodegenerative diseases, particularly Alzheimer’s disease. Disease-modifying therapies based on the pathophysiology of amyloidosis have now become available. Aducanumab, a human monoclonal antibody against the aggregated form of Aβ, was recently approved for Alzheimer’s disease, and other monoclonal antibodies, including gantenerumab, solanezumab, and lecanemab, could also be up for approval. As many other agents for amyloidosis will be developed in the future, studies to develop sensitive clinical scales for identifying improvement and markers that can act as surrogates for clinical scales should be conducted.

The Ultrastructure of Tissue Damage by Amyloid Fibrils

Amyloidosis is a group of diseases that includes Alzheimer’s disease, prion diseases, transthyretin (ATTR) amyloidosis, and immunoglobulin light chain (AL) amyloidosis. The mechanism of organ dysfunction resulting from amyloidosis has been a topic of debate. This review focuses on the ultrastructure of tissue damage resulting from amyloid deposition and therapeutic insights based on the pathophysiology of amyloidosis. Studies of nerve biopsy or cardiac autopsy specimens from patients with ATTR and AL amyloidoses show atrophy of cells near amyloid fibril aggregates. In addition to the stress or toxicity attributable to amyloid fibrils themselves, the toxicity of non-fibrillar states of amyloidogenic proteins, particularly oligomers, may also participate in the mechanisms of tissue damage. The obscuration of the basement and cytoplasmic membranes of cells near amyloid fibrils attributable to an affinity of components constituting these membranes to those of amyloid fibrils may also play an important role in tissue damage. Possible major therapeutic strategies based on pathophysiology of amyloidosis consist of the following: (1) reducing or preventing the production of causative proteins; (2) preventing the causative proteins from participating in the process of amyloid fibril formation; and/or (3) eliminating already-deposited amyloid fibrils. As the development of novel disease-modifying therapies such as short interfering RNA, antisense oligonucleotide, and monoclonal antibodies is remarkable, early diagnosis and appropriate selection of treatment is becoming more and more important for patients with amyloidosis.