AL Amyloidosis: Current Chemotherapy and Immune Therapy Treatment Strategies: JACC: CardioOncology State-of-the-Art Review

Screening for Systemic Light-Chain Amyloidosis in Patients Over 60 with λ Monoclonal Gammopathies

Background/Objectives: To reduce the early mortality of light-chain amyloidosis (AL), earlier diagnosis is needed. To pursue this goal, we conducted a multicenter study screening for AL λ-type (NCT04615572) in subjects > 60 years of age with λ smoldering myeloma (SMM) or monoclonal gammopathy of undetermined significance (MGUS), a light-chain differential (dFLC, λ minus κ) > 23 mg/L, and no prior amyloid diagnosis. Methods: Variables included AL-related IGVL gene usage and clonal plasma cell cytogenetic abnormalities, such as t(11;14) or gain 1q, which are present in 75% of AL cases. Here, 9 out of 33 λ IGVL genes, accounting for 90% of AL λ cases, were considered to be AL-related. Bone marrow was obtained, plasma cell cytogenetics and next generation sequencing for IGVL genes were performed, and subjects with AL-related IGVL genes were screened for AL using tissue studies. Results: From 2021 to 2023, we enrolled 30 subjects (19 M/11 F) with a median age of 68.5 years old (IQR 64.3-73), 17 SMM and 13 MGUS, with a median of 6% marrow plasma cells (range, 3.5-40). Here, 11 SMM and 4 MGUS cases had t(11;14) or gain 1q; 10/17 SMM and 12/13 MGUS had AL-related genes, and AL was ultimately confirmed by tissue biopsy in 3 with SMM. SMM, AL-related IGVL genes, and t(11;14) or gain 1q were found in 6 SMM subjects, including the 3 with AL (3/6 vs. 0/16; p < 0.05, Fisher's exact, two-tailed). Conclusions: These results justify a larger study screening for AL in SMM to develop a likelihood algorithm for AL using dFLC, IGVL gene usage, and the presence of t(11;14) or gain 1q.

Cardiac Amyloidosis in Older Adults With a Focus on Frailty: JACC: Advances Expert Consensus

Amyloidosis, which is caused by misfolded proteins that form amyloid fibrils, is predominantly diagnosed in older adults. Although previously considered a rare disease, increased awareness and noninvasive diagnostic methods have resulted in a rise in diagnoses. As a multisystem disease that affects multiple organ systems (cardiac, gastrointestinal, renal, and neurological), there is significant overlap with both geriatric conditions and common conditions in heart failure. Frailty is recognized as a distinct biological syndrome of declines across multiple physiological systems, which prevents maintenance of homeostasis and limits the ability to respond to stressors. Frailty was initially characterized as physical frailty alone; however, it is increasingly recognized that it is multidimensional with components including nutrition, cognitive, psychological, and social. Frailty in cardiovascular disease has become an important risk factor, indicator for disease severity, and can help guide decisions around intervention. In certain patients, frailty may be reversible. Given the lack of consensus definitions, tools, and implementation of frailty in both clinical and research settings in the field of amyloidosis, we convened a group of experts from cardiology, geriatric cardiology, geriatrics, hematology, and allied health to form this state-of-the-art review. There are many points of intersectionality between amyloidosis, aging, and frailty which herald a need for multidisciplinary care. This review document aims to provide guidance in how to understand and address frailty in older patients with a specific focus on cardiac amyloidosis.

Etiological Treatment of Cardiac Amyloidosis: Standard of Care and Future Directions

PURPOSE OF REVIEW

Cardiac amyloidosis (CA) is a condition caused by interstitial infiltration of misfolded proteins structured into amyloid fibrils. Transthyretin (ATTR) and immunoglobulin light chain (AL) amyloidosis represent the most common forms of CA. CA was traditionally perceived as a rare and incurable disease, but diagnostic and therapeutic advances have undermined the conventional paradigm.

RECENT FINDINGS

The standard of care for ATTR-CA include agents capable of selectively stabilizing the precursor protein (e.g., tafamidis), whereas the plasma cell clone is the main target of chemotherapy for AL-CA. For long, tafamidis represented the only drug approved for patients with ATTR-CA. Recent data from ATTRibute-CM led to the approval of acoramidis, whereas patisiran received refusal based on the APOLLO-B trial. Novel CRISPR-Cas9-based drugs (i.e., NTLA-2001) hold great potential in the setting of ATTR-CA. Several hematological regimens are available to treat AL-CA. The main limit of current therapies is their inability to trigger removal of amyloid from tissues. However, the investigation of monoclonal antibodies targeting misfolded ATTR (e.g., PRX004, NI301A) or AL (e.g., birtamimab, anselamimab) has led to encouraging results. Various cutting-edge strategies are being tested for treatment of CA and may change the prognostic landscape of this condition in the next years.

AL Amyloidosis: Current Treatment and Outcomes

Light chain AL amyloidosis is a systemic disorder involving tissue deposition of amyloid fibrils. Often delayed in diagnosis due to nonspecific systemic symptoms, AL amyloidosis must be confirmed on tissue biopsy. Once diagnosis is made, patients can be risk stratified based on the degree of organ involvement and high-risk cytogenetic features. Currently, the only FDA-approved first-line therapy for AL amyloidosis is a combination regimen of daratumumab, cyclophosphamide, bortezomib, and dexamethasone (DaraCyborD) with a goal of achieving a very good partial response (VGPR) after 4-6 cycles of treatment. Autologous stem cell transplant can be considered in selected cases, although there is no robust evidence of superiority over chemotherapy alone. In the relapsed/refractory setting, numerous promising therapies are still under investigation including venetoclax especially for patients with translocation t (11; 14) and chimeric antigen receptor T-cell therapy (CART) targeting B-cell maturation antigen (BCMA). Trial Registration: ClinicalTrials.gov identifier: NCT04270175, NCT05451771, NCT04847453, and NCT05199337.

Cardiac amyloidosis: Innovations in diagnosis and treatment

Cardiac amyloidosis (CA) is a progressive, underdiagnosed condition caused by the deposition of misfolded proteins in the myocardium, forming amyloid fibrils that impair cardiac structure and function. This review highlights recent advances in the diagnosis and treatment of amyloid light-chain (AL) and transthyretin (ATTR) CA, which globally account for most cases of CA. Novel diagnostic tools, including artificial intelligence-enhanced analysis and advanced imaging modalities like positron emission tomography with amyloid-specific tracers, might improve detection rates and diagnostic accuracy to enable non-invasive subtype differentiation. Furthermore, many innovative treatments are being investigated. For AL-CA, anti-fibril therapies are showing promising results, complementing traditional chemotherapy and autologous stem cell transplantation. In ATTR-CA, gene silencing and anti-fibril therapies are being tested in clinical trials and hold promise of halting disease progression and reducing amyloid deposits, respectively.

Light-chain (AL) amyloidosis for nephrologists-treatment standard

Amyloidosis is a group of complex diseases caused by the misfolding and aggregation of proteins into amyloid fibrils. Light-chain (AL) amyloidosis is one of the most prevalent forms of amyloidosis, characterized by the gradual proliferation of light chains from plasma cell clones. A growing body of evidence has contributed to our understanding of its pathogenesis, presentation and clinical course. Increased recognition of its clinical sequelae has increased the prevalence of AL amyloidosis. Renal involvement, seen in up to 70% of cases, is particularly challenging due to its impact on quality of life and access to treatment options. Thus, early recognition of its unique sequelae, appropriate staging and a comprehensive understanding of treatment options balanced by their organ toxicities are crucial to managing this disease. We review the current treatment standards and discuss novel developments in the pathophysiology, diagnosis, outcome prediction and management of AL amyloidosis for the Nephrologist.

Neutrophils enhance the clearance of systemic amyloid deposits in a murine amyloidoma model

Introduction

Amyloid-specific antibodies have been shown to opsonize and enhance amyloid clearance in systemic amyloidosis mouse models. However, the immunological mechanisms by which amyloid is removed have not been clearly defined. Previous reports from preclinical in vivo studies suggest polymorphonuclear cells (i.e., neutrophils) can affect amyloid removal. Therefore, we sought to analyze how neutrophils may contribute to the clearance of human AL amyloid extracts, using a murine amyloidoma model.

Methods

Immunocompromised nude mice injected subcutaneously with patient-derived AL amyloid extract (generating a localized "amyloidoma") were used to circumvent confounding factors contributed by the adaptive immune system and served as the model system. Two representative AL amyloid extracts were used, ALλ(CLA), which is refractory to clearance, and ALκ(TAL), which is readily cleared in mice. Neutrophil recruitment to the amyloid masses, cellular activation, and propensity to engulf amyloid were assessed.

Results

Immunophenotyping of amyloidomas from animals implanted with 2 mg of either ALλ or ALκ revealed that more neutrophils were recruited to ALκ amyloid masses as compared to the ALλ material, which was generally devoid of neutrophils. Ex vivo analyses indicated neutrophils do not efficiently phagocytose amyloid directly. However, histological evaluation of the ALκ amyloidoma revealed the abundant presence of neutrophil extracellular traps, which were absent in the ALλ amyloidomas. Using neutrophil depletion experiments in mice, we determined that mice devoid of neutrophils cleared the human amyloid lesions less efficiently. Moreover, mice devoid of neutrophils also had significantly reduced intra-amyloid expression of inflammatory cytokines.

Discussion

Neutrophils may not directly mediate amyloid clearance through phagocytosis; however, these cells can be stimulated by the amyloid and may function to facilitate phagocytosis and amyloid clearance by professional phagocytes (e.g., macrophages).

A review of recent clinical trials to evaluate disease-modifying therapies in the treatment of cardiac amyloidosis

Cardiac amyloidosis (CA) is a serious condition that results in infiltrative cardiomyopathy and heart failure with preserved ejection fraction (HFpEF) that is caused by the extracellular deposition of amyloid fibrils within heart tissue. While many important features of CA have been known for years, its prevalence in elderly patients with HF is increasingly being recognized. Plasma cells produce monoclonal immunoglobulin light chains which results in the formation and aggregation of amyloid fibrils that are responsible for AL amyloidosis. CA is classified as originating from either transthyretin (ATTR) or light chain (AL) amyloidosis. ATTR CA may result from a genetic mutation in the TTR gene, which is inherited (ATTRv), or from age-related deposition from wild-type ATTR (ATTRwt). Cardiac involvement in AL amyloidosis is attributed to either of two mechanisms: the extracellular deposition of amyloid fibril in the myocardium, or direct cardiotoxicity from the fibril aggregates. Typing of amyloid fibrils, a critical determinant of therapy, has also improved with wider availability of laser capture and mass spectrometry of histologic specimens. Specific and accurate evaluation of CA is now possible using cardiac magnetic resonance imaging and bone scintigraphy tracers. Survival in CA has improved markedly as novel chemotherapy agents have become available, but challenges remain in advanced disease. Broadening the amyloid-specific therapeutic landscape to include RNA inhibitors, fibril formation stabilizers and inhibitors, and immunotherapeutic targeting of amyloid deposits holds promise and may improve outcomes in systemic and cardiac amyloidoses. Treatment strategies for CA has recently undergone transformative changes, leading to some progress in outcomes for certain patients. Here, we discuss the basic features of CA as well as the emergence of novel, disease-modifying strategies that have been recently evaluated in clinical trials for the treatment of CA.

Radionuclide Imaging of Cardiac Amyloidosis: An Update and Future Aspects

Cardiac amyloidosis (CA) is caused by the misfolding, accumulation and aggregation of proteins into large fibrils in the extracellular compartment of the myocardium, leading to restrictive cardiomyopathy, heart failure and death. The major forms are transthyretin (ATTR) CA and light-chain (AL) CA, based on the respective precursor protein. Each of them requires early diagnosis for a timely treatment initiation that will improve patient outcomes. For this, radionuclide imaging is essentially used as single-photon emission computed tomography (SPECT) with bone-avid radiotracers or as positron emission tomography (PET) with amyloid-binding radiotracers. Both offer unprecedented specificity for the diagnostic of CA. SPECT has even revolutionized the diagnosis of ATTR-CA by making it non-invasive. Indeed, SPECT has now entered the standard diagnostic pathway to CA and has led to earlier diagnosis of the disease. SPECT also modified the epidemiology of ATTR-CA, highlighting that the disease is much more frequent than previously believed, and showing that ATTR-CA plays a substantial role in HFpEF and aortic stenosis, particularly among elderly patients. In parallel, amyloid-binding radiotracers for PET have accumulated a substantial amount of evidence, but are not approved for clinical use in CA yet. Further studies are needed to refine acquisition protocols and validate results in broader populations. Unlike bone-avid SPECT radiotracers, PET radiotracers have been specifically created to bind to amyloid fibrils. Thus, PET is the only imaging method that is truly specific for amyloid deposits and very sensitive to any amyloid type. Indeed, PET can not only detect ATTR-CA, but also AL-CA and rare hereditary forms. For both SPECT and PET, advances in quantitation of myocardial uptake have generated more granular and reproducible findings, paving the way for progress in earlier diagnosis, risk stratification and therapeutic response monitoring. Encouraging findings have shown that SPECT and PET are sensitive to early CA when other diagnostic methods are negative. Both radionuclide imaging techniques can predict adverse outcomes, but more evidence is needed to determine how to use them in conjunction with usual prognostic staging scores. Studies on follow-up imaging after therapy suggested that SPECT and PET can capture myocardial changes in CA, but again, more data are needed to meaningfully interpret such changes. Based on all these promising results, radionuclide imaging has the potential to further impact the landscape of CA in diagnosis, prognosis and follow-up, but also to substantially contribute to the assessment of novel therapies that will improve the lives of patients with CA.

Breast calcifications on mammography from systemic amyloidosis: A case report

Calcifications on mammography from systemic disease at times meet diagnostic criteria for histologic sampling to exclude malignancy. We present a case of bilateral groups of new calcifications on mammography that yielded amyloidosis on core biopsy. Awareness of our patient's known diagnosis of systemic light chain amyloidosis (AL) prompted use of Congo red staining to confirm the histologic diagnosis. Knowledge of systemic diseases with possible manifestations on mammography can facilitate cogent and clinically relevant radiology-pathology correlation.

A Case of Solitary Amyloid Lung Nodule Treated With Surgery

Primary or light-chain (AL) (lambda) amyloidosis is a rare systemic disorder that is characterized by the misfolding of autologous proteins and the extracellular deposition of abnormally folded proteins composed of immunoglobulin light chains, often caused by plasma cell dyscrasias. We present a unique case of a 57-year-old female with multiple comorbidities, including extensive smoking history and chronic kidney disease, who was incidentally discovered to have a left upper lobe lung nodule on a chest X-ray prompted by complaints of shortness of breath. The patient underwent biopsy of the lung nodule, and by utilizing the gold standard diagnostic technique of a Congo red stain, positive test results confirmed the diagnosis of AL amyloidosis. However, additional investigations, including bone marrow and fat pad biopsies, were negative for plasma cell dyscrasias. The patient subsequently underwent a wedge resection of the nodule, and a follow-up positron emission tomography-computed tomography (PET-CT) scan showed only post-surgical changes in the left upper lobe of the lung without evidence of disease progression or systemic involvement. Given the asymptomatic and multisystem symptomology of most cases, treatment options for AL amyloidosis are individualized. This case discusses pulmonary nodular AL amyloidosis and highlights the diagnostic and treatment options for this disorder.

The mechanism of action, pharmacological characteristics, and clinical utility of the amyloid depleter birtamimab for the potential treatment of AL amyloidosis

Amyloid light chain (AL) amyloidosis is a progressive plasma cell disorder caused by amyloid deposition resulting in organ damage and failure. Current standard-of-care treatments target clonal plasma cells, the source of misfolded light chains (amyloid precursors), yet only half of patients with advanced disease survive ≥6 months. The amyloid depleter birtamimab is an investigational humanized monoclonal antibody that binds misfolded κ and λ light chains with high specificity and was designed to neutralize soluble toxic light chain aggregates and promote phagocytic clearance of deposited amyloid. Post hoc analyses from the Phase 3 VITAL trial suggested birtamimab plus standard of care confers a survival benefit in patients with advanced (Mayo Stage IV) AL amyloidosis. AFFIRM-AL (NCT04973137), a Phase 3 confirmatory trial of birtamimab plus standard of care in patients with Mayo Stage IV AL amyloidosis, is ongoing. This review summarizes birtamimab's mechanism of action, attributes, and potential clinical utility.

Clonal hematopoiesis of indeterminate potential in patients with immunoglobulin light-chain AL amyloidosis

ABSTRACT

Immunoglobulin light-chain (AL) amyloidosis is characterized by the deposition of misfolded monoclonal free light chains, with cardiac complications accounting for patient mortality. Clonal hematopoiesis of indeterminate potential (CHIP) has been associated with worse cardiovascular outcomes in the general population. Its significance in AL amyloidosis remains unclear. We collected clinical information and outcome data on 76 patients with a diagnosis of AL amyloidosis who underwent deep targeted sequencing for myeloid neoplasia-associated mutations between April 2018 and August 2023. Variant allele frequency was set at 2% to call CHIP-associated mutations. CHIP mutations were present in patients with AL amyloidosis at a higher frequency compared with age-matched control individuals. Sixteen patients (21%) had at least 1 CHIP mutation. DNMT3A was the most frequent mutation (7/16; 44%). Compared with patients without CHIP, patients with CHIP had a higher prevalence of t(11;14) translocation (69% vs 25%, respectively; P = .004). Furthermore, among patients with renal involvement, those with CHIP had a lower Palladini renal stage (P = .001). At a median follow-up of 32.5 months, the presence of CHIP was not associated with worse overall survival or major organ dysfunction progression-free survival. Larger studies and longer follow-up are needed to better define the impact of CHIP in patients with AL amyloidosis.

Cardiac Amyloidosis Mimicking Non-ST-Segment Myocardial Infarction: A Case Report

Cardiac amyloidosis is a rare but increasingly recognized condition characterized by the deposition of amyloid fibrils in cardiac tissue, leading to structural and functional heart impairment. This infiltrative cardiomyopathy often mimics more common cardiac conditions, posing significant diagnostic challenges. Particularly deceptive is its presentation as non-ST-segment elevation myocardial infarction (NSTEMI), where the clinical overlap necessitates considering amyloidosis in differential diagnoses. A 75-year-old male presented with muscle weakness, respiratory infection symptoms, and elevated cardiac enzymes. His history included a recent hospitalization for NSTEMI, with normal coronary angiography. Initial evaluations showed elevated troponin and CRP levels. A comprehensive cardiac assessment revealed a dilated ascending aorta, moderate systolic dysfunction (left ventricular ejection fraction (LV-EF), 47%), and asymmetrical interventricular septal thickening, suggesting hypertrophic cardiomyopathy or amyloidosis. The patient improved and was referred for further specialized care. Cardiac amyloidosis can mimic acute coronary syndrome (ACS), presenting with chest pain and elevated cardiac biomarkers. Differentiation is critical as amyloidosis involves myocardial infiltration by amyloid proteins, leading to restrictive cardiomyopathy. Advanced imaging techniques like cardiac MRI and nuclear scintigraphy are essential for accurate diagnosis and appropriate management, impacting therapeutic strategies and patient outcomes.

Pathophysiology of Cardiac Amyloidosis

Amyloidosis refers to a heterogeneous group of disorders sharing common pathophysiological mechanisms characterized by the extracellular accumulation of fibrillar deposits consisting of the aggregation of misfolded proteins. Cardiac amyloidosis (CA), usually caused by deposition of misfolded transthyretin or immunoglobulin light chains, is an increasingly recognized cause of heart failure burdened by a poor prognosis. CA manifests with a restrictive cardiomyopathy which progressively leads to biventricular thickening, diastolic and then systolic dysfunction, arrhythmias, and valvular disease. The pathophysiology of CA is multifactorial and includes increased oxidative stress, mitochondrial damage, apoptosis, impaired metabolism, and modifications of intracellular calcium balance.

Multi-parametric non-contrast cardiac magnetic resonance for the differentiation between cardiac amyloidosis and hypertrophic cardiomyopathy

AIM

To evaluate the ability of fast strain-encoded (SENC) cardiac magnetic resonance (CMR) derived myocardial strain and native T1 mapping to discriminate between hypertrophic cardiomyopathy (HCM) and cardiac amyloidosis.

METHODS

Ninety nine patients (57 with hypertrophic cardiomyopathy and 42 with cardiac amyloidosis) were systematically analysed. LV-ejection fraction, LV-mass index, septal wall thickness and native T1 mapping values were assessed. In addition, global circumferential and longitudinal strain and segmental circumferential and longitudinal strain in basal, mid-ventricular, and apical segments were calculated. A ratio was built by dividing native T1 values by basal segmental strain (T1-to-basal segmental strain ratio).

RESULTS

Myocardial strain was equally distributed in apical and basal segments in HCM patients, whereas an apical sparing with less impaired apical strain was noticed in cardiac amyloidosis (apical-to-basal-ratio of 1.01 ± 0.23 versus 1.20 ± 0.28, p < 0.001). T1 values were significantly higher in amyloidosis compared to HCM patients (1170.7 ± 66.4 ms versus 1078.3 ± 57.4ms, p < 0.001). The T1-to-basal segmental strain ratio exhibited high accuracy for the differentiation between the two clinical entities (Sensitivity = 85%, Specificity = 77%, AUC = 0.90, 95% CI = 0.81-0.95, p < 0.001). Multivariable analysis showed that age and the T1-to-basal-strain-ratio were the most robust factors for the differentiation between HCM and cardiac amyloidosis.

CONCLUSION

The T1-to-basal-segmental strain ratio, combining information from segmental circumferential and longitudinal strain and native T1 mapping aids the differentiation between HCM and cardiac amyloidosis with high accuracy and within a fast CMR protocol, obviating the need for contrast agent administration.

Towards etiological treatments in cardiomyopathies

This review proposes to look at the evolution of cardiomyopathy treatments in the light of advances in diagnostic techniques, which have enabled to move from a mechanistic to a phenotypic and then etiological approach. The article goes beyond the ejection fraction approach, and look at new therapies that target the pathophysiological pathways of cardiomyopathies, either by targeting the phenotype, or by targeting the etiology. The evolution of HCM treatments is detailed, culminating in the latest etiological treatments such as mavacamten in sarcomeric HCM, tafamidis in transthyretin cardiac amyloidosis and migalastat in Fabry disease. Myosin stimulators are reviewed in the treatment of DCM, before opening perspectives for gene therapy, which proposes direct treatment of the culprit mutation.

Cardiac Toxicity in the Treatment of Light Chain Amyloidosis: Systematic Review of Clinical Studies

BACKGROUND

Light chain amyloidosis (AL) is a progressive and a fatal disease that primarily affects cardiac tissue. Although the current approach to anti-amyloidosis treatments has managed to reduce amyloidosis morbimortality, the dynamics of cardiac adverse events are unknown.

OBJECTIVE

to provide evidence about reported cardiac toxicity during treatment of AL amyloidosis through a systematic review of the literature.

METHODS

A search was performed for registered clinical trials on ClinicalTrials.gov filtered for AL amyloidosis up to December 31, 2022. Studies were filtered by those that reported intervention in patients with AL amyloidosis and that had reported adverse events. The type of study, the intervention performed, and the frequency of reported cardiac adverse events were discriminated from each trial.

RESULTS

25 clinical trials were analyzed, representing a population of 1,542 patients, among whom 576 (38.95%) adverse events were reported, 326 being serious (SAE) and 242 nonserious (nSAE). The most frequent SAEs were cardiac failure, atrial fibrillation, and cardiac arrest, while the most frequent nSAEs were palpitations, atrial fibrillation, and sinus tachycardia.

CONCLUSION

cardiac toxicity during treatment for amyloidosis seems common, and it is important to evaluate the relationship of therapies with its occurrence.

Pulmonary manifestations of amyloidosis

Amyloidosis is caused by abnormal protein deposition in various tissues, including the lungs. Pulmonary manifestations of amyloidosis may be categorized by areas of involvement, such as parenchymal, large airway and pleural involvement. We describe four distinct manifestations of amyloidosis involving the lung and review their clinical, radiological and pathological features and summarize the evidence for treatment in each of these presentations. We describe alveolar-septal amyloidosis, cystic amyloid lung disease, endobronchial amyloidosis and pleural amyloidosis.

Epidemiology and clinical outcomes of light-chain amyloidosis in Sweden: A nationwide population-based study

OBJECTIVES

This study evaluated data from six Swedish national registries to fill current evidence gaps on the epidemiology, clinical burden, and overall survival (OS) associated with light-chain (AL) amyloidosis.

METHODS

Patients newly diagnosed with AL amyloidosis were identified using six linked Swedish nationwide population-based registers. For each case, individuals from the general population were selected and matched with a maximum ratio of 1:5 based on age, sex, calendar year, and county.

RESULTS

846 patients newly diagnosed with AL amyloidosis and 4227 demographically matched individuals were identified. From 2011 to 2019, annual AL amyloidosis incidence increased from 10.5 to 15.1 cases per million. At baseline, patients with AL amyloidosis had a significantly higher disease burden including higher rates of cardiac and renal failure relative to the comparison group. Among patients with AL amyloidosis, 21.5% had incident heart failure and 17.1% had incident renal failure after initial diagnosis. Median OS for patients with AL amyloidosis was 56 months versus not reached in the matched general population comparison group.

CONCLUSION

The incidence of newly diagnosed AL amyloidosis in Sweden increased over time with AL amyloidosis being associated with a higher risk of cardiac/renal failure and all-cause mortality compared with the general population.

Myocardial Characterization for Early Diagnosis, Treatment Response Monitoring, and Risk Assessment in Systemic Light-Chain Amyloidosis

Aims

In systemic light-chain (AL) amyloidosis, cardiac involvement portends poor prognosis. Using myocardial characteristics on magnetic resonance imaging (MRI), this study aimed to detect early myocardial alterations, to analyze temporal changes with plasma cell therapy, and to predict risk of major adverse cardiac events (MACE) in AL amyloidosis.

Methods and Results

Participants with recently diagnosed AL amyloidosis were prospectively enrolled. Presence of AL cardiomyopathy (AL-CMP vs. AL-non-CMP) was determined by abnormal cardiac biomarkers. MRI was performed at baseline and 6 months, with 12-month imaging in AL-CMP cohort. MACE was defined as all-cause death, heart failure hospitalization, or cardiac transplantation. Mayo AL stage was based on troponin T, NT-proBNP, and difference in free light chains. The study cohort included 80 participants (median age 62 years, 58% males). Median left ventricular extracellular volume (ECV) was significantly higher in AL-CMP (53% vs. 30%, p<0.001). ECV was abnormal (>32%) in all AL-CMP and in 47% of AL-non-CMP. ECV tended to increase at 6 months and decreased significantly from 6 to 12 months in AL-CMP (median -3%, p=0.011). ECV was strongly associated with MACE (p<0.001), and improved MACE prediction when added to Mayo AL stage (p=0.002). ECV≤32% identified a cohort without MACE, while ECV>48% identified a cohort with 74% MACE.

Conclusions

In AL amyloidosis, ECV detects subclinical cardiomyopathy. ECV tends to increase from baseline to 6 months and decreases significantly from 6 and 12 months of plasma cell therapy in AL-CMP. ECV provides excellent risk stratification and offers additional prognostic performance over Mayo AL stage.

Prognostic Value of Left Ventricular 18 F-Florbetapir Uptake in Systemic Light-Chain Amyloidosis

Background

Myocardial immunoglobulin light-chain (AL) amyloid deposits trigger heart failure, cardiomyocyte stretch and myocardial injury, leading to adverse cardiac outcomes. Positron emission tomography/computed tomography (PET/CT) with 18 F-florbetapir, a novel amyloid-targeting radiotracer, can quantify left ventricular (LV) amyloid burden, but its prognostic value is not known. Therefore, we aimed to evaluate the prognostic value of LV amyloid burden quantified by 18 F-florbetapir PET/CT and to identify mechanistic pathways mediating its association with outcomes.

Methods

Eighty-one participants with newly-diagnosed systemic AL amyloidosis were prospectively enrolled and underwent 18 F-florbetapir PET/CT. LV amyloid burden was quantified using 18 F-florbetapir LV percent injected dose (%ID). Mayo AL stage was determined using troponin T, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and difference between involved and uninvolved free light chain levels. Major adverse cardiac events (MACE) were defined as all-cause death, heart failure hospitalization, or cardiac transplantation within 12 months.

Results

Among participants (median age 61 years, 57% males), 36% experienced MACE. Incidence of MACE increased across tertiles of LV amyloid burden from 7% to 63% (p<0.001). LV amyloid burden was significantly associated with MACE in univariable analysis (hazard ratio 1.45, 95% confidence interval 1.15-1.82, p=0.002). However, this association became non-significant in multivariable analyses adjusted for Mayo AL stage. Mediation analysis showed that the association between 18 F-florbetapir LV %ID and MACE was primarily mediated by NT-proBNP (p<0.001), a marker of cardiomyocyte stretch and component of Mayo AL stage.

Conclusion

In this first study to link cardiac 18 F-florbetapir uptake to subsequent outcomes, LV amyloid burden estimated by LV %ID predicted MACE in AL amyloidosis. But this effect was not independent of Mayo AL stage. LV amyloid burden was associated with MACE primarily via NT-pro-BNP, a marker of cardiomyocyte stretch and component of Mayo AL stage. These findings provide novel insights into the mechanism through which myocardial AL amyloid leads to MACE.

Clinical Perspective

In systemic light-chain (AL) amyloidosis, cardiac involvement is the key determinant of adverse outcomes. Usually, prognosis is based on the Mayo AL stage, determined by troponin T, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and the difference between involved and uninvolved immunoglobulin free light chain levels (dFLC). Cardiac amyloid burden is not considered in this staging. In the present study, we used the amyloid-specific radiotracer 18 F-florbetapir to quantify left ventricular (LV) amyloid burden in 81 participants with newly-diagnosed AL amyloidosis and evaluated its prognostic value on major adverse outcomes (MACE: all-cause death, heart failure hospitalization, or cardiac transplantation within 12 months). We found that higher LV amyloid burden by 18 F-florbetapir positron emission tomography/computed tomography (PET/CT) was strongly associated with MACE. However, this association became non-significant after adjustment for the Mayo AL stage. Mediation analysis offered novel pathophysiological insights, implying that LV amyloid burden leads to MACE predominantly through cardiomyocyte stretch and light chain toxicity (by NT-proBNP), rather than through myocardial injury (by troponin T), also considering the severity of plasma cell dyscrasia (by dFLC). This mediation by NT-proBNP may explain why the association with outcomes was non-significant with adjustment for Mayo AL stage. Together, these results establish quantitative 18 F-florbetapir PET/CT as a valid method to predict adverse outcomes in AL amyloidosis. These results support the use of 18 F-florbetapir PET/CT to measure the effects of novel fibril-depleting therapies, in addition to plasma cell therapy, to improve outcomes in systemic AL amyloidosis.

Collagen inhibits phagocytosis of amyloid in vitro and in vivo and may act as a 'don't eat me' signal

BACKGROUND

Systemic amyloidosis refers to a group of protein misfolding disorders characterized by the extracellular deposition of amyloid fibrils in organs and tissues. For reasons heretofore unknown, amyloid deposits are not recognized by the immune system, and progressive deposition leads to organ dysfunction.

METHODS

In vitro and in vivo phagocytosis assays were performed to elucidate the impact of collagen and other amyloid associated proteins (eg serum amyloid p component and apolipoprotein E) had on amyloid phagocytosis. Immunohistochemical and histopathological staining regimens were employed to analyze collagen-amyloid interactions and immune responses.

RESULTS

Histological analysis of amyloid-laden tissue indicated that collagen is intimately associated with amyloid deposits. We report that collagen inhibits phagocytosis of amyloid fibrils by macrophages. Treatment of 15 patient-derived amyloid extracts with collagenase significantly enhanced amyloid phagocytosis. Preclinical mouse studies indicated that collagenase treatment of amyloid extracts significantly enhanced clearance as compared to controls, coincident with increased immune cell infiltration of the subcutaneous amyloid lesion.

CONCLUSIONS

These data suggest that amyloid-associated collagen serves as a 'don't eat me' signal, thereby hindering clearance of amyloid. Targeted degradation of amyloid-associated collagen could result in innate immune cell recognition and clearance of pathologic amyloid deposits.

Cardiovascular toxicity from therapies for light chain amyloidosis

Amyloid light-chain (AL) amyloidosis is a hematological disorder characterized by abnormal proliferation of a plasma cell clone producing monoclonal free light chains that misfold and aggregate into insoluble fibrils in various tissues. Cardiac involvement is a common feature leading to restrictive cardiomyopathy and poor prognosis. Current first-line treatments aim at achieving hematological response by targeting the plasma cell clones, and these have been adapted from multiple myeloma therapy. Patients with AL amyloidosis often exhibit multiorgan involvement, making them susceptible to cancer therapy-related cardiovascular toxicity. Managing AL amyloidosis is a complex issue that requires enhanced knowledge of the cardio-oncological implications of hematological treatments. Future research should focus on implementing and validating primary and secondary prevention strategies and understanding the biochemical basis of oncological therapy-related damage to mitigate cardiovascular toxicity.

Cardiovascular Toxicity of Proteasome Inhibitors in Multiple Myeloma Therapy

The treatment for multiple myeloma has advanced significantly over the past few decades. Proteasome inhibitors have become the cornerstone of the treatment of multiple myeloma. However, proteasome inhibitors have shown cardiovascular complications such as hypertension, pulmonary hypertension, heart failure, arrhythmias, ischaemic heart disease and thromboembolism. Detection, monitoring and management of proteasome inhibitor-related cardiovascular toxicity are essential to improve clinical outcomes for patients. Proposed mechanisms of proteasome inhibitor-related cardiovascular toxicity are apoptosis, prolonged inhibition of the ubiquitin-proteasome system, accumulation of improperly folded proteins within cardiomyocytes and higher protein phosphatase 2A activity. To better understand the mechanisms underlying cardiotoxicity, further in vitro and in vivo experiments are required to investigate these hypotheses. Combined use of metformin or angiotensin II receptor blockers with the proteasome inhibitor, carfilzomib, showed an emerging role as a prophylactic therapy because they can preserve heart function in multiple myeloma patients. Metformin is expected to be an effective therapeutic intervention for the management of carfilzomib-induced cardiotoxicity. There has been evidence that three compounds, apremilast, rutin, and dexrazoxane, can reverse carfilzomib-induced cardiotoxicity in rats. The future transition from animal experiments to clinical trials is worth waiting for.

A case report of isolated cardiac light chain amyloidosis without clinically overt heart failure: an under-recognized presentation

Background

Cardiac involvement in amyloid light-chain (AL) amyloidosis usually represents a brick in the wall of a multi-system disease. The presence of cardiac deposition of free light chains (FLCs) is the main determinant of survival. Isolated cardiac AL is an uncommon scenario characterized by a challenging diagnostic and therapeutic workup.

Case summary

A 57-year-old asymptomatic man was presented for an incidental finding of myocardial necrosis at the electrocardiogram (ECG) performed for newly diagnosed arterial hypertension. Alongside signs of previous myocardial infarction, transthoracic echocardiography showed a severely increased left ventricular (LV) wall thickness not consistent with ECG voltages, segmental akinaesia with normal LV systolic function with 'apical sparing' pattern. Laboratory assessment showed an unexpectedly high level of natriuretic peptide and persistently abnormal troponin in the absence of symptoms or signs of heart failure or ongoing ischaemia. Coronary angiogram confirmed the coronary artery disease. Before revascularization, a complete diagnostic workup was carried. Serum electrophoresis detected a monoclonal gammopathy that was further investigated by serum immunofixation, revealing high lambda FLCs concentration. Fat pad, bone marrow, and salivary glands biopsies resulted negative for amyloid deposition. Finally, endomyocardial biopsy was consistent with AL amyloidosis. Urgent percutaneous revascularization was performed, and the patients was timely started on chemotherapy.

Discussion

The diagnosis of isolated cardiac AL amyloidosis is challenging and carries important therapeutic implications. As the short-term prognosis might be severely compromised, an accurate diagnostic flowchart has to be systematically pursued to obtain a precise diagnosis and address the optimal, tailored management.

Evaluation of contemporary echocardiographic and histomorphology parameters in predicting mortality in patients with endomyocardial biopsy-proven cardiac AL amyloidosis

Introduction

This study examined the role of echocardiographic and cardiac histomorphology parameters in predicting mortality in patients with cardiac AL amyloidosis.

Methods

Patients with endomyocardial biopsy-proven cardiac AL amyloidosis treated at MD Anderson Cancer Center between 6/2011 and 6/2020 were identified. Stored echocardiographic images and endomyocardial biopsy samples were processed for myocardial strain analysis and a detailed histomorphology characterization.

Results

Of 43 patients; 44% were women and 63% white. Median age was 65 years; 51% underwent stem cell transplantation (SCT). Thirty patients (70%) died during follow up (median follow up: 4.1 years). Lower LA strain (<13.5%) and absence of SCT as a time-varying covariate were significantly associated with increased risk of death in the multivariate cox regression analysis. Higher LV mass and lower RV tricuspid annular plane systolic excursion were associated with increased odds of having ≥5% interstitial amyloid deposition on biopsy in the multivariate logistic regression analysis.

Conclusion

Lower LA strain independently predicted mortality in our cohort, and its performance in the routine assessment of AL amyloidosis may be beneficial. Furthermore, SCT for cardiac AL amyloidosis was associated with improved OS. These findings need to be confirmed by larger studies in the era of contemporary systemic therapies.

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.

The Clinical Characteristics of Immunoglobulin Light Chain Amyloidosis in the Chinese Population: A Systematic Scoping Review

Immunoglobulin light chain (AL) amyloidosis is the most common type of systemic amyloidosis in China and is associated with increased morbidity and a poor prognosis. However, the clinical characteristics of Chinese patients with AL amyloidosis have not been systematically investigated. This scoping review aimed to summarize the available literature regarding the clinical characteristics of patients with AL amyloidosis and identify potential knowledge gaps. We searched three electronic databases from inception to 7 February 2021. PICOS (Patient, Intervention, Comparison, Outcome and Study) design structure was used to formulate the data extraction. All statistical calculations and analyses were performed with R (version 3.6.0). Sixty-seven articles with 5022 patients were included. Results suggest Chinese patients were younger (57 years) at the time of diagnosis when compared with other patient populations and were predominantly male (61.2%). The time interval from the onset of symptoms to diagnosis was between 6 and 12 months. It was found that 41.1% of Chinese patients with AL amyloidosis were diagnosed with an advanced stage III disease when diagnosed, and 20.2% had a concurrent disease. The most involved organs were the kidneys (84.3%) and the heart (62.5%). In conclusion, our study shows some similarities and differences with other studies on the clinical characteristics of Chinese patients with AL amyloidosis, including the age at diagnosis, Mayo stage, and organ involvement. However, a nationwide epidemiological investigation is still needed to provide a comprehensive overview of this patient population in China.

Beyond Sarcomeric Hypertrophic Cardiomyopathy: How to Diagnose and Manage Phenocopies

PURPOSE OF REVIEW

We describe the most common phenocopies of hypertrophic cardiomyopathy, their pathogenesis, and clinical presentation highlighting similarities and differences. We also suggest a step-by-step diagnostic work-up that can guide in differential diagnosis and management.

RECENT FINDINGS

In the last years, a wider application of genetic testing and the advances in cardiac imaging have significantly changed the diagnostic approach to HCM phenocopies. Different prognosis and management, with an increasing availability of disease-specific therapies, make differential diagnosis mandatory. The HCM phenotype can be the cardiac manifestation of different inherited and acquired disorders presenting different etiology, prognosis, and treatment. Differential diagnosis requires a cardiomyopathic mindset allowing to recognize red flags throughout the diagnostic work-up starting from clinical and family history and ending with advanced imaging and genetic testing. Different prognosis and management, with an increasing availability of disease-specific therapies make differential diagnosis mandatory.

Idiopathic membranous nephropathy with renal amyloidosis: A case report

Background

Immunoglobulin light chain amyloidosis is a clonal, non-proliferative plasma cell disorder, in which fragments of immunoglobulin light chain are deposited in tissues. Clinical features depend on organs involved but can include restrictive cardiomyopathy, nephrotic syndrome, hepatic failure, peripheral/autonomic neuropathy, and atypical multiple myeloma. Membranous nephropathy (MN) is a group of diseases characterized by deposition of immune complexes under the epithelial cells of glomerular basement and diffuse thickening of the basement membrane. Most patients with idiopathic MN (IMN) have been exposed to phospholipase A2 receptor (PLA2R) antigen, and anti-PLA2R antibodies that attack podocytes can be detected in their blood. IMN combined with amyloidosis nephropathy without secondary factors is rare. The present study describes a patient with IMN combined with immunoglobulin light chain amyloidosis nephropathy.

Case report

A 39-year-old man was admitted to our hospital because of weight loss and edema. His clinical manifestation was nephrotic syndrome. Renal pathology revealed MN. A positive Congo red staining and the pathognomonic apple-green birefringence under cross-polarized light were considered to be associated with amyloid nephropathy. Immunofluorescence showed that λ light chain was positive. Heavy chain deposition disease and amyloid-associated protein amyloidosis were excluded by immunofluorescence and immunohistochemistry, respectively. Subsequent examinations showed that his serum was negative for antibodies against the PLA2R, but PLA2R was present in renal tissue. The final diagnosis was IMN with light chain amyloid nephropathy.

Conclusion

Renal amyloidosis accompanied by IMN is uncommon. Attention should be paid to the subtype of the disease and the exclusion of secondary factors. Perfect clinical and pathological examination are helpful for the classification and staging of the disease. Congo red staining, light microscopy, immunofluorescence, immunohistochemistry, electron microscopic examination, pathological tissue staining for PLA2R antigen and testing for anti-PLA2R antibody in serum are helpful.

Axillary Lymphadenopathy as an Initial Presentation of Systemic Amyloidosis: A Case Report and Literature Review

Amyloidosis rarely presents as localized lymphadenopathy. Various studies have elucidated the varied presentation and manifestations of this interesting disease. We reviewed the literature and found 36 cases of primary amyloidosis with lymph node enlargement as a presentation, and 17 of the 36 cases (47%) had systemic involvement on further work up. We describe a patient who presented with an isolated right axillary mass. Clinical examination and radiology were indicative of a lymph node enlargement with no evidence of malignancy in the breasts or lungs. Histopathological examination was indicative of amyloidosis. A further work up including serum, urine biochemistry, cardiac work up, bone marrow examination, and a kidney biopsy revealed systemic amyloidosis. Patient was treated with daratumumab and CyBorD (cyclophosphamide, bortezomib, and dexamethasone) followed by a stem cell transplantation. Patient is in remission for 1 year, at the time of submission of this report. Therefore, we conclude (1) systemic amyloidosis presenting as an isolated lymph node enlargement is rare, (2) a structured systemic work up is imperative for early diagnosis and proper management of amyloidosis, when there is an index of suspicion, and (3) use of novel therapeutic options such as CD38 + antibody (daratumumab) and stem cell transplant have positive impact on disease outcomes.

Impact of cardiac amyloidosis on outcomes of patients hospitalized with heart failure

BACKGROUND

Amyloidosis is a multi-systemic disease potentially leading to failure of affected organs. We aimed to investigate prevalence and prognostic implications of cardiac amyloidosis of any etiology on outcomes of hospitalized patients with heart failure (HF) in Germany.

METHODS

We analyzed data of the German nationwide inpatient sample (2005-2018) of patients hospitalized for HF (including myocarditis with HF and heart transplantation with HF). HF patients with amyloidosis (defined as cardiac amyloidosis [CA]) were compared with those HF patients without amyloidosis and impact of CA on outcomes was assessed.

RESULTS

During this fourteen-year observational period 5,478,835 hospitalizations for HF were analyzed. Amyloidosis was coded in 5,407 HF patients (0.1%). CA prevalence was 1.87 hospitalizations per 100,000 German population. CA patients were younger (75.0[IQR 67.0-80.0]vs.79.0[72.0-85.0]years, p < 0.001), predominantly male (68.9%) and had a higher prevalence of cancer (14.8% vs. 3.6%, p < 0.001). Adverse in-hospital events including necessity of transfusions of blood constituents (7.1% vs. 5.4%, p < 0.001) and cardio-pulmonary resuscitation (CPR, 2.7% vs. 1.4%; p < 0.001) were more frequent in CA. CA was independently associated with acute kidney failure (OR 1.40 [95%CI 1.28-1.52], p < 0.001), CPR (OR 1.58 [95%CI 1.34-1.86], p < 0.001), intracerebral bleeding (OR 3.13 [95%CI 1.68-5.83], p < 0.001) and in-hospital mortality between the 5 and 8th decade of life, but in-hospital mortality was strongly influenced by cancer.

CONCLUSIONS

CA was identified as an independent risk factor for complications and in-hospital mortality in HF patients, whereby it has to be mentioned that amyloidosis subtypes could not differentiated in the present study. Physicians should be aware of this issue concerning treatments and monitoring of CA-patients.

Cardiac amyloidosis-interdisciplinary approach to diagnosis and therapy

The vast majority of cardiac amyloidosis (CA) cases are caused by light chain (AL) or transthyretin (ATTR) amyloidosis. The latter is divided into hereditary (ATTRv) and wild-type forms (ATTRwt). The incidence of ATTRwt amyloidosis has significantly increased, particularly due to the improved diagnosis of cardiac manifestations, with relevant proportions in patient populations with heart failure (HF) and preserved ejection fraction (HFpEF). Cardiac amyloidosis should be suspected in HF with indicative clinical scenarios/"red flags" with typical signs of CA in echocardiography. Further noninvasive imaging (cardiovascular magnetic resonance imaging, scintigraphy) and specific laboratory diagnostics are important for the diagnosis and typing of CA into the underlying main forms of ATTR and AL amyloidosis. The histopathologic analysis of an endomyocardial biopsy is necessary if noninvasive diagnostic methods do not enable reliable typing of CA. This is crucial for initiating specific therapy. Therapy of HF in CA is largely limited to the use of diuretics in the absence of evidence on the benefit of classic HF therapy with neurohormonal modulators. Innovative therapies have been developed for amyloidosis with improvement in organ protection, prognosis, and quality of life. These include specific cytoreductive therapies for monoclonal light-chain disease in AL amyloidosis and pharmacologic stabilization or inhibition of transthyretin expression in ATTR amyloidosis. Since the CA underlying amyloidosis is a systemic disease also affecting other organ systems, close interdisciplinary cooperation is crucial for rapid and effective diagnosis and therapy.

Effect of ligands with different affinity on albumin fibril formation

The effect of binding of several ligands to bovine serum albumin on the kinetics of fibril formation at denaturing conditions is studied. The considered ligands are clinical drugs with different binding constants to albumin: relatively strong binders (naproxen, ibuprofen, warfarin with 10⁵ to 10⁷ binding constant values) and weak binders (isoniazid, ranitidine with 10³ to 10⁴ binding constant values). The data of thioflavin fluorescence binding assay, Congo red binding assay, and circular dichroism spectroscopy indicate ligand concentration-dependent suppression of fibril formation in the presence of strong binders and no effects in the presence of weak binders. Analysis of kinetic curves shows no induction lag associated with fibril nucleation and the first-order kinetics of fibril formation with respect to albumin concentration for all the studied systems. Using DSC method, the fractions of unfolded albumin at incubation temperature were determined for each albumin-ligand system and ligand concentration. Their magnitudes ranging from 0 to 1 correlate with the initial rates of fibril formation and with equilibrium concentrations of fibrils formed in the system after incubation for at least 120 min. The results indicate that fibrils are formed from partially or completely denatured albumin form with the rate proportional to the fraction of this form. Strong albumin binders act as thermodynamic inhibitors of fibrillation shifting the unfolding equilibrium to the side of the native ligand-bound protein.

Opportunities for Earlier Diagnosis and Treatment of Cardiac Amyloidosis

Despite the rapid expansion of noninvasive (nonbiopsy) diagnosis, contemporary patients with cardiac amyloidosis too often present with advanced features of disease, such as diminished quality of life, elevated natriuretic peptides, and advanced heart failure. Therapeutics for transthyretin cardiomyopathy (ATTR-CM) are most effective when administered before significant symptoms of cardiac dysfunction manifest, making early identification of affected individuals of paramount importance. Community engagement and ensuring that a broad range of clinicians have working knowledge of how to screen for ATTR-CM in everyday practice will be an important step in moving disease identification further upstream. However, reliance on the appropriate and timely diagnosis by individual clinicians may continue to underperform. This review highlights how targeted screening of special populations may facilitate earlier diagnosis. Systems of care that operationalize screening of high-risk subpopulations and prospective validation of novel approaches to ATTR-CM identification are needed.

Molecular Mechanisms of Cardiac Amyloidosis

Cardiac involvement has a profound effect on the prognosis of patients with systemic amyloidosis. Therapeutic methods for suppressing the production of causative proteins have been developed for ATTR amyloidosis and AL amyloidosis, which show cardiac involvement, and the prognosis has been improved. However, a method for removing deposited amyloid has not been established. Methods for reducing cytotoxicity caused by amyloid deposition and amyloid precursor protein to protect cardiovascular cells are also needed. In this review, we outline the molecular mechanisms and treatments of cardiac amyloidosis.