A Changing Landscape of Mortality for Systemic Light Chain Amyloidosis

Development and validation of an early prediction model for cardiac death risk in patients with light chain amyloidosis: a multicenter study

BACKGROUND

Cardiac involvement is the primary driver of death in systemic light chain (AL) amyloidosis. However, the early prediction of cardiac death risk in AL amyloidosis remains insufficient.

OBJECTIVES

We aimed to develop a novel prediction model and prognostic scoring system that enables early identification of these high-risk individuals.

METHODS

This study enrolled 235 patients with confirmed AL cardiac amyloidosis from three hospitals. Patients from the first hospital were randomly assigned to the training and internal validation sets in an 8:2 ratio, while the external validation set comprised patients from the other two hospitals. Participants were categorized into a cardiac death group and a non-cardiac death group (including survivors and those who died from other causes). Five different machine learning models were used to train model, and model performance was evaluated using receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis.

RESULTS

All five models showed excellent performance on the training and internal validation sets. In external validation, both the Logistic Regression (LR) and Random Forest models achieved an area under the ROC curve of 0.873 and 0.877, respectively, and exhibited superior calibration and decision curve analysis. Considering the comprehensive performance and clinical applicability, the LR model was selected as the final prediction model. The visualization results are ultimately presented in a nomogram. Further analyses were performed on the newly identified predictors.

CONCLUSIONS

This prediction model enables early identification and risk assessment of cardiac death in patients with AL amyloidosis, exhibiting considerable predictive ability.

A model for predicting day-100 stem cell transplant-related mortality in AL amyloidosis

Autologous stem cell Transplant (ASCT)-related mortality (TRM) in AL amyloidosis remains elevated. AL amyloidosis patients (n = 1718) from 9 centers, transplanted 2003-2020 were included. Pre-ASCT variables of interest were assessed for association with day-100 all-cause mortality. A random forest (RF) classifier with 10-fold cross-validation assisted in variable selection. The final model was fitted using logistic regression. The median age at ASCT was 58 years. Day-100 TRM occurred in 75 patients (4.4%) with the predominant causes being shock, high-grade arrhythmia, and organ failure. Ten factors were associated with day-100 TRM on univariate analysis. RF classifier using these variables generated a model with an area under the curve (AUC) of 0.72 ± 0.12. To refine the model selection using importance hierarchy function, a 4-variable model [NT-proBNP/BNP, serum albumin, ECOG performance status (PS), and systolic blood pressure] was built with an AUC of 0.70 ± 0.12. Based on logistic regression coefficients, ECOG PS 2/3 was assigned two points while other adverse predictors 1-point each. The model score range was 0-5, with a day-100 TRM of 0.46%, 3.2%, 5.8%, and 14.5% for 0, 1, 2, and ≥3 points, respectively. This model to predict day-100 TRM in AL amyloidosis allows better-informed decision-making in this heterogeneous disease.

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.

Metabolomics and machine learning approaches for diagnostic biomarkers screening in systemic light chain amyloidosis

Delayed diagnosis of systemic light chain (AL) amyloidosis is common and associated with worse survival and early mortality. Current diagnosis still relies on invasive tissue biopsies, highlighting the need for sensitive, noninvasive biomarkers for early diagnosis. This study aims to identify promising biomarkers for the early diagnosis of AL amyloidosis. Peripheral venous blood samples from 70 newly diagnosed systemic AL amyloidosis patients, 48 newly diagnosed multiple myeloma (MM) patients, and 29 healthy controls (HCs) were analyzed using high-performance liquid chromatography-mass spectrometry. Metabolomic profiling revealed distinct metabolic differences between the AL group and the controls (HCs and MM). Machine learning further identified that phytosphingosine and asymmetric dimethylarginine were significantly up-regulated in the AL group compared with HCs group, with area under curve (AUC) values of 0.990 and 0.904, sensitivity and specificity of (97%, 100%) and (88%, 93%), respectively. Compared with MM group, phytosphingosine was also significantly up-regulated in the AL group, with an AUC value of 0.779, sensitivity and specificity of (62%, 88%). Pathway analysis showed significant changes in starch and sucrose metabolism pathway, as well as pentose and glucuronate interconversions pathway between the AL and the controls. Metabolomics combined with machine learning identified phytosphingosine as a promising biomarker for early diagnosis of AL amyloidosis. Two metabolic pathways (starch and sucrose metabolism, pentose and glucuronate interconversions) may reflect the key pathological processes involved in the development and progression of AL amyloidosis. Further confirmation studies are warranted to validate its value in this field.

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

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

Antibody Aggregation: A Problem Within the Biopharmaceutical Industry and Its Role in AL Amyloidosis Disease

Due to the large size and rapid growth of the global therapeutic antibody market, there is major interest in understanding the aggregation of protein products as it can compromise efficacy, concentration, and safety. Various production and storage conditions have been identified as capable of inducing aggregation of polyclonal and monoclonal antibody (mAb) therapies such as low pH, freezing, light exposure, lyophilisation and increased ionic strength. The addition of stabilising excipients to these therapeutics helps to combat the formation of aggregates with future aggregation inhibition mechanisms involving the introduction of point mutations and glycoengineering within aggregation prone regions (APRs). Antibody aggregation also plays an integral role in the pathogenesis of a condition known as amyloid light chain (AL) amyloidosis which is characterised by the production of improperly folded and amyloidogenic immunoglobulin light chains (LCs). Current diagnostic tools rely heavily on histological staining with their future moving towards amyloid component identification and proteomic analysis. For many years, treatment options designed for multiple myeloma (MM) have been applied to AL amyloidosis patients by depleting plasma cell numbers. More recently, treatment strategies more specific to this condition have been developed with many designed to recognize amyloid fibrils and trigger their degradation without causing systemic plasma cell cytotoxicity. Amyloid fibrils in AL disease and aggregates in antibody therapeutics are both formed through the oligomerisation of misfolded / modified proteins attempting to reach a thermodynamically stable, free energy minimum that is lower than the respective monomers themselves. Although the final morphologies are different, by understanding the principles underlying such aggregation, we expect to find common insights that may contribute to the development of new and effective methods of antibody aggregation and/or amyloidosis management. We envision that this area of research will continue to be very relevant in both industry and clinical settings.

Multifaceted pulmonary manifestations of amyloidosis: state-of-the-art update

INTRODUCTION

Amyloidosis, a polymeric deposition disease classified according to protein subtype, may have varied pulmonary manifestations. Its anatomic-radiologic phenotypes include nodular, cystic, alveolar-septal, and tracheobronchial forms. Clinical presentation may range from asymptomatic parenchymal nodules to respiratory failure from diffuse parenchymal infiltration or diaphragmatic deposition.

AREAS COVERED

In this review, we systematically describe the molecular subtypes of amyloidosis and their clinical and radiologic findings in the lungs as well as key extrapulmonary organ systems. We detail novel treatment approaches to systemic amyloidosis. We also discuss prognostic elements for each subtype. We identify key clinical scenarios where reaching a precise diagnosis can be complicated, and we offer insights on the varied presentations of pulmonary amyloidosis.

EXPERT OPINION

Pulmonary amyloidosis is often difficult to diagnose as it may mimic other conditions, including fibrotic interstitial lung diseases and neoplasms, or can co-exist with certain connective tissue diseases. Despite some early artificial intelligence screening tools, improved familiarity among clinicians can aid in the more accurate and timely diagnosis of this multidimensional clinical entity. We additionally believe that multidisciplinary clinical pathwaysto diagnose and/or treat pulmonary amyloidosis have the potential to improve awareness, decrease diagnostic delay, and further elucidate knowledge on this multifaceted disease.

First report of the clinical characteristics and outcomes of cardiac amyloidosis in Saudi Arabia

AIMS

Cardiac amyloidosis (CA) is a potentially fatal multisystemic disease that remains significantly underdiagnosed, particularly in the Middle East. This study aims to evaluate the prevalence and clinical characteristics of CA in a high-risk population at a tertiary centre in Saudi Arabia.

METHODS

This cross-sectional, retrospective, single-centre study was conducted at a tertiary hospital in Riyadh, Saudi Arabia. We reviewed the medical records of heart failure patients seen between August 2018 and July 2022 who exhibited red flags for CA and subsequently underwent CA screening. Red flags that prompted the workup included at least two of the following factors: the presence of unilateral or bilateral carpal tunnel syndrome, a family history of transthyretin amyloid (ATTR) amyloidosis and specific electrocardiographic features (relative/absolute low QRS voltage, pseudoinfarct pattern and atrioventricular/interventricular conduction abnormalities). Echocardiographic red flags included mainly increased wall thickness (≥12 mm), significant diastolic dysfunction, reduced left ventricular (LV) longitudinal function, right ventricular (RV) dysfunction and elevated right atrial (RA)/pulmonary artery (PA) pressure. Cardiac magnetic resonance (CMR) red flags included aspects similar to those in an echocardiogram as well as a subendocardial or transmural late gadolinium enhancement (LGE) pattern. These patients were assessed for CA through technetium-99m pyrophosphate ([99mTc]Tc-PYP) bone scintigraphy, serum and urine protein electrophoresis with immunofixation and a serum-free light chain assay.

RESULTS

A total of 177 patients were screened, of which 21.0 (11.9%) patients were diagnosed with transthyretin amyloid CA (ATTR-CA) and 13 (7.3%) patients were diagnosed with light chain CA (AL-CA). Compared with patients with negative/equivocal [99mTc]Tc-PYP scans (grades 0-1), patients with positive [99mTc]Tc-PYP scans (grades 2-3) were older (78.0 vs. 68.0 years, P < 0.001), had higher levels of troponin (P = 0.003) and N-terminal pro-brain natriuretic peptide (NT-proBNP) (P < 0.001), had a higher LV mass index (P < 0.001), displayed a more depressed global longitudinal strain (GLS) (P < 0.001) with a greater prevalence of a relative apical sparing pattern (P < 0.001) and demonstrated a higher incidence of first-degree atrioventricular block (P = 0.008) and low voltage patterns on electrocardiography (P < 0.001). Patients with ATTR-CA and AL-CA were more likely to have a subendocardial or transmural LGE pattern on CMR (P < 0.001) and had a significantly lower overall survival (P < 0.001) when compared with other heart failure aetiologies.

CONCLUSIONS

This is the first study to describe the clinical characteristics and outcomes of CA in the Middle East and Saudi Arabia. The prevalence of CA among screened heart failure patients here aligns with major international studies, suggesting significant underdiagnosis in the region. Therefore, larger multicentric studies and regional screening programmes are urgently needed to accurately characterize the epidemiology and outcomes of CA in the Middle East.

Impact of the Noninvasive Diagnostic Algorithm on Clinical Presentation and Prognosis in Cardiac Amyloidosis

Background

The introduction of a noninvasive diagnostic algorithm in 2016 led to increased awareness and recognition of cardiac amyloidosis (CA).

Objectives

The purpose of this study was to analyze the impact of the introduction of the noninvasive diagnostic algorithm on diagnosis and prognosis in a multicenter Italian CA cohort.

Methods

This was a retrospective analysis of 887 CA patients from 5 Italian Cardiomyopathies Referral Centers: 311 light-chain CA, 87 variant transthyretin (TTR)-related CA, 489 wild-type TTR-related CA. Clinical characteristics and outcomes (all-cause mortality and heart failure [HF] hospitalizations) were compared overall and for each CA subtype between patients diagnosed before versus after 2016. Outcomes were further compared by propensity score weighted Kaplan-Meier analysis and Cox regression analysis.

Results

CA diagnoses increased after 2016, in particular for wild-type TTR-related CA. Patients diagnosed after versus before 2016 were older, had less frequently a history of HF prior to diagnosis, and NYHA functional class III-IV at diagnosis. Over a median follow-up of 18 months, 172 (86%) patients diagnosed before 2016 died or had an HF hospitalization, versus 300 (44%) diagnosed after 2016. Propensity score weighted Kaplan-Meier analysis showed worse outcomes (P < 0.001) for patients diagnosed before 2016. At Cox regression analysis, CA diagnosis after 2016 was an independent protective factor for the composite outcome (HR: 0.69; P = 0.001), with interaction by CA subtype (significant in TTR-related CA and null in light-chain).

Conclusions

CA patients diagnosed after 2016 showed a less severe phenotype and a better prognosis. The impact of the noninvasive diagnostic algorithm on outcomes was particularly relevant in TTR-related CA.

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.

Preservation of Circumferential and Radial Left Ventricular Function as a Mitigating Mechanism for Impaired Longitudinal Strain in Early Cardiac Amyloidosis

BACKGROUND

In patients with cardiac amyloidosis (CA), left ventricular ejection fraction (LVEF) is frequently preserved, despite commonly reduced global longitudinal strain (GLS). We hypothesized that nonlongitudinal contraction may initially serve as a mitigating mechanism to maintain cardiac output and studied the relationship between global circumferential (GCS) and radial (GRS) strain with LVEF and extracellular volume (ECV), a marker of amyloid burden.

METHODS

Patients with CA who underwent cardiac magnetic resonance (CMR; n = 140, 70.7 ± 11.5 years, 66% male) or echocardiography (n = 67, 71 ± 13 years, 66% male) and normal controls (CMR, n = 20; echocardiography, n = 45) were retrospectively identified, and GCS, GLS, and GRS were quantified using feature-tracking CMR or speckle-tracking echocardiography and compared between CA patients with preserved and reduced LVEF (CAHFpEF, CAHFrEF) and controls. The prevalence of impaired strain (magnitudes <2.5th percentile of the controls) was compared between CAHFpEF and CAHFrEF and between ECV quartiles.

RESULTS

While echocardiography-derived GLS was impaired in both CAHFpEF (-13.4% ± 3.1%, P < .003) and CAHFrEF (-9.1% ± 3.2%, P < .003), compared with controls (-20.8% ± 2.4%), GCS was more impaired in CAHFrEF compared with both controls (-15.6% ± 5.0% vs -32.3% ± 3.3%, P < .003) and CAHFpEF (-30.4% ± 5.7%, P < .003) and did not differ between CAHFpEF and controls (P = .24). The prevalence of abnormal CMR-derived GCS (P < .0001) and GRS (P < .0001) but not GLS (P = .054) varied significantly across ECV quartiles.

CONCLUSIONS

Among CA patients with preserved LVEF, preserved GCS and GRS, despite near-universally impaired GLS, may be explained by an initial predominantly subendocardial involvement, where mostly longitudinal fibers are located. If confirmed in future studies, these findings may facilitate identification of patients with early stages of CA, when treatments may be most effective.

Cardiac amyloidosis and aortic stenosis: a state-of-the-art review

Cardiac amyloidosis is caused by the extracellular deposition of amyloid fibrils in the heart, involving not only the myocardium but also any cardiovascular structure. Indeed, this progressive infiltrative disease also involves the cardiac valves and, specifically, shows a high prevalence with aortic stenosis. Misfolded protein infiltration in the aortic valve leads to tissue damage resulting in the onset or worsening of valve stenosis. Transthyretin cardiac amyloidosis and aortic stenosis coexist in patients > 65 years in about 4-16% of cases, especially in those undergoing transcatheter aortic valve replacement. Diagnostic workup for cardiac amyloidosis in patients with aortic stenosis is based on a multi-parametric approach considering clinical assessment, electrocardiogram, haematologic tests, basic and advanced echocardiography, cardiac magnetic resonance, and technetium labelled cardiac scintigraphy like technetium-99 m (99mTc)-pyrophosphate, 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid, and 99mTc-hydroxymethylene diphosphonate. However, a biopsy is the traditional gold standard for diagnosis. The prognosis of patients with coexisting cardiac amyloidosis and aortic stenosis is still under evaluation. The combination of these two pathologies worsens the prognosis. Regarding treatment, mortality is reduced in patients with cardiac amyloidosis and severe aortic stenosis after undergoing transcatheter aortic valve replacement. Further studies are needed to confirm these findings and to understand whether the diagnosis of cardiac amyloidosis could affect therapeutic strategies. The aim of this review is to critically expose the current state-of-art regarding the association of cardiac amyloidosis with aortic stenosis, from pathophysiology to treatment.

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.

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.

In-hospital mortality in amyloid light chain amyloidosis: analysis of the Premier Healthcare Database

Aim: Describe the clinical and economic burden of hospitalizations for amyloid light chain (AL) amyloidosis. Materials & methods: This retrospective analysis used nationally representative hospital discharge data (2017-2020) to report discharge status, resource use and costs for hospitalizations among patients with AL amyloidosis. Results: Of 1341 patients identified, 92% were discharged alive and 8% experienced in-hospital death. Compared with the average US hospital stay during 2017-2019 (4.7 days, mean costs of $13,046 and mean charges of $54,496), hospital stays for AL amyloidosis were longer and costlier (9.7 days, $27,098.61, $111,233.91), especially in patients with in-hospital death (12.2 days, $44,966, $182,338.18). Conclusion: AL amyloidosis is associated with significant clinical and economic burden.

Implications of Extra-cardiac Disease in Patient Selection for Heart Transplantation: Considerations in Cardiac Amyloidosis

Disease-modifying therapies in both light chain and transthyretin amyloidosis have improved patient functional status and survival. Conceivably, as heart failure may progress despite amyloid therapies, more patients may be considered for heart transplantation. In earlier eras, extra-cardiac amyloid deposits significantly reduced post-heart transplant patient survival and functional status compared to the non-amyloid population. In the modern era, transplant centres have reported improved outcomes in amyloidosis as patient selection has grown more stringent. Importantly, systematic candidate evaluation should assess the degree of extra-cardiac involvement, the effectiveness of disease-modifying therapies and downstream effects on patients' nutrition and frailty. This review outlines such an overall approach while also considering that organ-specific selection criteria may vary between individual transplant centres. A methodical approach to patient evaluation will promote better understanding of the prevalence and severity of extra-cardiac disease in amyloidosis patients referred for heart transplantation and of any disparities in decision outcomes in this population.

Non-invasive diagnosis of transthyretin cardiac amyloidosis utilizing typical late gadolinium enhancement pattern on cardiac magnetic resonance and light chains

AIMS

While cardiac magnetic resonance (CMR) is often obtained early in the evaluation of suspected cardiac amyloidosis (CA), it currently cannot be utilized to differentiate immunoglobulin (AL) and transthyretin (ATTR) CA. We aimed to determine whether a novel CMR and light-chain biomarker-based algorithm could accurately diagnose ATTR-CA.

METHODS AND RESULTS

Patients with confirmed AL or ATTR-CA with typical late gadolinium enhancement (LGE) and Look-Locker pattern for CA on CMR were retrospectively identified at three academic medical centres. Comprehensive light-chain analysis including free light chains, serum, and urine electrophoresis/immunofixation was performed. The diagnostic accuracy of the typical CMR pattern for CA in combination with negative light chains for the diagnosis of ATTR-CA was determined both in the entire cohort and in the subset of patients with invasive tissue biopsy as the gold standard. A total of 147 patients (age 70 ± 11, 76% male, 51% black) were identified: 89 ATTR-CA and 58 AL-CA. Light-chain biomarkers were abnormal in 81 (55%) patients. Within the entire cohort, the sensitivity and specificity of a typical LGE and Look-Locker CMR pattern and negative light chains for ATTR-CA was 73 and 98%, respectively. Within the subset with biopsy-confirmed subtype, the CMR and light-chain algorithm were 69% sensitive and 98% specific.

CONCLUSION

The combination of a typical LGE and Look-Locker pattern on CMR with negative light chains is highly specific for ATTR-CA. The successful non-invasive diagnosis of ATTR-CA using CMR has the potential to reduce diagnostic and therapeutic delays and healthcare costs for many patients.

Immunoglobulin Light Chain Amyloidosis: Diagnosis and Risk Assessment

Immunoglobulin light chain (AL) amyloidosis is a clonal plasma cell disorder with multiple clinical presentations. The diagnosis of AL amyloidosis requires a high index of suspicion, making a delay in diagnosis common, which contributes to the high early mortality seen in this disease. Establishing the diagnosis of AL amyloidosis requires the demonstration of tissue deposition of amyloid fibrils. A bone marrow biopsy and fat pad aspirate performed concurrently have a high sensitivity for the diagnosis of AL amyloidosis and negate the need for organ biopsies in most patients. An accurate diagnosis requires amyloid typing via additional testing, including tissue mass spectrometry. Prognostication for AL amyloidosis is largely driven by the organs impacted. Cardiac involvement represents the single most important prognostic marker, and the existing staging systems are driven by cardiac biomarkers. Apart from organ involvement, plasma cell percentage on the bone marrow biopsy, specific fluorescence in situ hybridization findings, age at diagnosis, and performance status are important prognostic markers. This review elaborates on the diagnostic testing and prognostication for patients with newly diagnosed AL amyloidosis.

Current Understanding of Systemic Amyloidosis and Underlying Disease Mechanisms

Amyloidosis is a group of diverse disorders caused by misfolded proteins that aggregate into insoluble fibrils and ultimately cause organ damage. In medical practice, amyloidosis classification is based on the amyloid precursor protein type, of which amyloid immunoglobulin light chain, amyloid transthyretin, amyloid leukocyte chemotactic factor 2, and amyloid derived from serum amyloid A protein are the most common. Distinct mechanisms appear to be predominantly operational in the pathogenesis of particular types of amyloidosis, including increased protein precursor synthesis, somatic or germ line mutations, and inherent instability in the precursor protein in its wild form. An increased supply of misfolded proteins and/or a decreased capacity of the protein quality control systems can result in an imbalance that leads to increased circulation of misfolded proteins. Although the detection of mature fibrils is the basis for diagnosis of amyloidosis, a growing body of evidence has implicated the prefibrillar species as proteotoxic and key contributors to the development of the disease.

Noncardiac Manifestations of Hereditary Amyloidosis

The most common forms of cardiac amyloidosis are progressive, life threatening, and underrecognized. Symptoms affect a variety of organs and overlap with those of more common conditions, complicating and postponing diagnosis. Cardiac disease generally determines mortality, but noncardiac manifestations typically surface before cardiac symptoms, often several years before diagnosis. Familiarity with noncardiac manifestations may lead to early diagnosis, enabling treatment and improving prognosis.

Treatment patterns and outcomes in light chain amyloidosis: An institutional registry of amyloidosis report in Argentina

Light chain (AL) amyloidosis is a form of systemic amyloidosis, causing organ dysfunction, mainly affecting the heart and kidney. Patient-tailored and risk-adapted decision making is critical in AL amyloidosis management. There is limited real-world evidence data from Argentina and Latin America regarding the treatment approaches for AL amyloidosis. This retrospective cohort study aimed to describe the treatment patterns and outcomes in adult patients (>18 years) diagnosed with AL amyloidosis at the Hospital Italiano in Buenos Aires, Argentina, using a 10-yearfollow-up data (June 1, 2010 to May 31, 2019) from the institutional registry of amyloidosis (IRA). The study population had a mean age of 63 years and 54.4% weremale. Heart and kidney were the most frequently affected organs. Of the 90 eligible patients included in the study, 70underwent treatment. Bortezomib-based regimen was the preferred first-line treatment (75.7% patients). Overall,54.4% of the patients presented a deep response (complete or very good partial response). Median overall survival (OS) was 5years, the 1-year OS and progression free survival rates were 80% (95% confidence interval [CI]: 68–87) and 80% (95%CI 68–87)), respectively. This study provides vital real-world evidence for the long-term treatment patterns and survival in a large cohort of AL amyloidosis patients in Argentina.

Real-world treatment patterns, costs, and outcomes in patients with AL amyloidosis: analysis of the Optum EHR and commercial claims databases

BACKGROUND

This study characterised real-world treatment patterns, clinical outcomes, and cost-of-illness in patients with light-chain (AL) amyloidosis.

METHODS

Data were extracted from the US-based Optum® EHR and Clinformatics® Data Mart (claims) databases (2008-2019) for patients newly diagnosed with AL amyloidosis and who initiated anti-plasma cell therapies. Healthcare resource utilisation (HCRU) and related costs were compared across lines of therapy (LOT). Incidences of cardiac and renal failure were evaluated using the Kaplan-Meier method.

RESULTS

About 1347 patients (EHR, n = 776; claims, n = 571) were included. Median age was 68 years; 56.8% were male. At initial diagnosis, 33.1% and 15.1% of patients had cardiac and renal failure, respectively. Most patients received bortezomib-containing treatment in LOT1 (69%); bortezomib-cyclophosphamide-dexamethasone was most common (26%). HCRU was similar across LOTs. Mean per-patient-per-month and per-patient-per-LOT costs were $19,343 and $105,944 for LOT1, $19,183 and $95,793 for LOT2, and $16,611 and $128,446 for LOT3, respectively. Costs were primarily driven by anti-plasma cell therapies, outpatient visits, and hospitalisations. The 5-year cardiac and renal failure rates following initial diagnosis were 64.5% and 39.0%, respectively.

CONCLUSION

AL amyloidosis is associated with substantial costs and suboptimal outcomes, highlighting the need for new therapeutic approaches to prevent organ deterioration, and reduce disease burden.

Global epidemiology of amyloid light-chain amyloidosis

Background

Amyloid light-chain (AL) amyloidosis is an ultra-rare disease associated with significant morbidity and mortality. Few studies have examined the global epidemiology of this condition.

Methods

This study estimated the diagnosed incidence and 1-year, 5-year, 10-year, and 20-year period prevalence of AL amyloidosis in 2018 for countries in and near Europe, and in the United States (US), Canada, Brazil, Japan, South Korea, Taiwan, and Russia. A systematic literature review (SLR) was conducted to identify country-specific, age- and gender-specific diagnosed incidence of AL amyloidosis and observed survival data-point inputs for an incidence-to-prevalence model. Extrapolations were used to estimate incidence and prevalence for countries without registry or published epidemiological data.

Results

Of 171 publications identified in the SLR, 10 records met the criteria for data extraction, and two records were included in the final incidence-to-prevalence model. In 2018, an estimated 74,000 AL amyloidosis cases worldwide were diagnosed during the preceding 20 years. The estimated incidence and 20-year prevalence rates were 10 and 51 cases per million population, respectively.

Conclusions

Orphan medicinal product designation criteria of the European Medicines Agency or Electronic Code of Federal Regulations indicate that a disease must not affect > 5 in 10,000 people across the European Union or affect < 200,000 people in the US. This study provides up-to-date epidemiological patterns of AL amyloidosis, which is vital for understanding the burden of the disease, increasing awareness, and to further research and treatment options.

Coexistent transthyretin amyloid cardiomyopathy and monoclonal gammopathy: Diagnostic challenges and prognostic implications

Establishing an accurate diagnosis of amyloid subtype in patients with coexistent cardiac amyloidosis and monoclonal gammopathy is crucial due to treatment and prognostic implications. Here, we discuss a case of coexistent diagnoses of transthyretin amyloid cardiomyopathy and smoldering multiple myeloma, highlighting the challenges associated with the possibility of several disease combinations and the limitations of diagnostic testing. In addition, the importance of clinical clues such as disease course and progression, patient preference, and multidisciplinary collaboration should not be discounted in the diagnostic and management approach of these patients.

Two Decades of Cardiac Amyloidosis: A Danish Nationwide Study

Background

Cardiac amyloidosis (CA) has been associated with poor outcomes. Screening studies suggest that CA is overlooked-especially in the elderly. Recent advances in treatment have brought attention to the disease, but data on temporal changes in CA epidemiology are sparse.

Objectives

The aim of this work was to describe all patients with CA in Denmark, examining changes in patient characteristics from 1998 to 2017.

Methods

All patients with any form of amyloidosis diagnosed from 1998 to 2017, as well as their comorbidities and pharmacotherapy, were identified in Danish nationwide registries. CA was defined as any diagnosis code for amyloidosis combined with a diagnosis code for heart failure, cardiomyopathy, or atrial fibrillation or a procedural code for pacemaker implantation, regardless of the order. The index date was defined as the date of meeting those criteria. Patients were divided into 5-year periods by index date. For comparison, we also included control subjects (1:4 ratio) from the general population.

Results

CA criteria were met by 619 patients. Comparing 1998-2002 vs 2013-2017, the median age at baseline increased from 67.4 years (interquartile range [IQR]: 53.9-75.2 years) to 72.3 years (IQR: 66.0-79.3 years). The frequency of male patients increased from 62.1% to 66.2%. The incidence of CA rose from 0.88 to 3.56 per 100,000 person-years in the Danish population aged ≥65 years, and the 2-year mortality decreased from 82.6% (IQR: 69.9%-90.5%) to 50.2% (IQR: 43.1%-56.9%). Compared with control subjects, the mortality among CA patients was significantly higher (log-rank test: P < 0.0001).

Conclusions

CA, as defined in this study, was increasingly diagnosed on a national scale. The increasing frequency of male patients and median age suggest that wild-type transthyretin amyloidosis is driving this increase. Greater recognition of earlier, less advanced cases might explain decreasing mortality.

Recent advances in the diagnosis and management of amyloid cardiomyopathy

Amyloidosis is a disorder characterized by misfolded precursor proteins that form depositions of fibrillar aggregates with an abnormal cross-beta-sheet conformation, known as amyloid, in the extracellular space of several tissues. Although there are more than 30 known amyloidogenic proteins, both hereditary and non-hereditary, cardiac amyloidosis (CA) typically arises from either misfolded transthyretin (ATTR amyloidosis) or immunoglobulin light-chain aggregation (AL amyloidosis). Its prevalence is more common than previously thought, especially among patients with heart failure and preserved ejection fraction (HFpEF) and aortic stenosis. If there is a clinical suspicion of CA, focused echocardiography, laboratory screening for the presence of a monoclonal protein (serum and urinary electrophoresis with immunofixation and serum free light-chain ratio), and cardiac scintigraphy with 99mtechnetium-labeled bone-tracers are sensitive and specific initial diagnostic tests. In some cases, more advanced/invasive techniques are necessary and, in the last several years, treatment options for both AL CA and ATTR CA have rapidly expanded. It is important to note that the aims of therapy are different. Systemic AL amyloidosis requires treatment targeted against the abnormal plasma cell clone, whereas therapy for ATTR CA must be targeted to the production and stabilization of the TTR molecule. It is likely that a multistep treatment approach will be optimal for both AL CA and ATTR CA. Additionally, treatment of CA includes the management of restrictive cardiomyopathy with preserved or reduced ejection fraction in addition to treating the amyloid deposition. Future studies are necessary to define optimal management strategies for AL CA and ATTR CA and confirm cardiac response to therapy.

Use of biomarkers to diagnose and manage cardiac amyloidosis

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

Heart failure from ATTRwt amyloid cardiomyopathy is associated with poor prognosis

Aims

Amyloid cardiomyopathy is an underappreciated cause of morbidity and mortality. Recent evidence suggests that ATTR wild‐type cardiomyopathy (ATTRwt‐CM) is probably much more common than widely appreciated. So far, no data are available on comparison of mortality from ATTRwt‐CM and other heart failure aetiologies.

Methods and results

This was a retrospective, observational, cohort study of 2251 patients and their data collected prospectively from May 2000 to June 2018. Long‐term mortality was the main outcome measure. Underlying cardiomyopathies were classified as amyloid CM (6.1%) [ATTRwt 3.0%; light‐chain amyloidosis (AL) 3.1%], dilated CM (dCMP) (46.4%), ischaemic heart disease (IHD) (24.4%), hypertensive heart disease (HHD) (14.6%), hypertrophic CM (HCM) (5.1%), and valvular heart disease (VHD) (3.4%). Median duration of follow‐up was 7.1 years (interquartile range 3.4–11.3). Five‐year overall survival in the whole cohort was 80.1%. In multivariate analysis, individuals with amyloid CM were 3.74 times [95% confidence interval (CI) 2.72–5.14; P < 0.001] more likely to die of any reason than were individuals with dCMP. Mortality was higher in AL‐CM compared with ATTRwt‐CM [hazard ratio (HR) 2.88; 95% CI 1.48–5.58; P = 0.002]. Mortality rates in patients with ATTRwt‐CM were higher than in patients with dCMP (HR 1.96; 95% CI 1.24–3.22; P = 0.007), HCM (HR 2.94; 95% CI 1.28–6.67; P = 0.011), HHD (HR 2.08; 95% CI 1.27–3.45; P = 0.004), VHD (HR 2.38; 95% CI 1.30–4.35; P = 0.005), or left ventricular ejection fraction ≥ 40% (HR 1.99; 95% CI 1.12–3.52; P = 0.018).

Conclusions

Our study demonstrates that amyloid CM is independently associated with poor survival among patients with various causes of heart failure. ATTRwt‐CM had a better long‐term prognosis than did AL‐CM, but was associated with higher mortality than were dCMP, HCM, HHD, VHD, and heart failure with preserved or mid‐range ejection fraction.

Endomyocardial Biopsy Characterization of Heart Failure With Preserved Ejection Fraction and Prevalence of Cardiac Amyloidosis

OBJECTIVES

This study prospectively evaluated endomyocardial biopsies in patients with heart failure with preserved ejection fraction (HFpEF) to identify histopathologic phenotypes and their association with clinical characteristics.

BACKGROUND

Myocardial tissue analysis from a prospectively defined HFpEF cohort reflecting contemporary comorbidities is lacking.

METHODS

Patients with HFpEF (EF ≥50%) referred to the Johns Hopkins HFpEF Clinic between August 2014 and September 2018 were enrolled for right heart catheterization and endomyocardial biopsy. Clinical features, echocardiography, hemodynamics, and tissue histology were determined and compared with controls (unused donor hearts) and HF with reduced EF (HFrEF).

RESULTS

Of the 108 patients enrolled, median age was 66 years (25th to 75th percentile: 57 to 74 years), 61% were women, 57% were African American, 62% had a previous HF hospitalization, median systolic blood pressure was 141 mm Hg (25th to 75th percentile: 125 to 162 mm Hg), body mass index (BMI) was 37 kg/m² (25th to 75th percentile: 32 to 45 kg/m²), and 97% were on a loop diuretic. Myocardial fibrosis and myocyte hypertrophy were often present (93% and 88%, respectively); however, mild in 71% with fibrosis and in 52% with hypertrophy. Monocyte infiltration (CD68+ cells/mm²) was greater in patients with HFpEF versus controls (60.4 cells/mm² [25th to 75th percentile: 36.8 to 97.8] vs. 32.1 cells/mm² [25th to 75th percentile: 22.3 to 59.2]; p = 0.02) and correlated with age and renal disease. Cardiac amyloidosis (CA) was diagnosed in 15 (14%) patients (HFpEF-CA: 7 patients with wild-type transthyretin amyloidosis [ATTR], 4 patients with hereditary ATTR, 3 patients with light-chain amyloidosis, and 1 patient with AA (secondary) amyloidosis), of which 7 cases were unsuspected. Patients with HFpEF-CA were older, with lower BMI, higher left ventricular mass index, and higher N-terminal pro-B-type natriuretic peptide and troponin I levels.

CONCLUSIONS

In this large, prospective myocardial tissue analysis of HFpEF, myocardial fibrosis and hypertrophy were common, CD68+ inflammation was increased, and CA prevalence was 14%. Tissue analysis in HFpEF might improve precision therapies by identifying relevant myocardial mechanisms.

Insight from an autopsy in a patient with rapidly worsening heart failure due to amyloid light-chain cardiac amyloidosis: A case report

Amyloid light-chain (AL) amyloidosis is a systemic disease characterized by the deposition of misfolded immunoglobulin light chain, causing organ failure, and in particular cardiac involvement is a leading cause of morbidity and mortality. We report the case of a 47-year-old man without prior cardiovascular events who presented with shortness of breath. He was diagnosed with primary AL cardiac amyloidosis (CA) from the laboratory test, the endomyocardial biopsy, the bone marrow examination, and the cardiovascular imaging. Only a week after discharge of the first heart failure (HF) admission, he was readmitted for the exacerbation of HF. Finally, he died 2 weeks after the second admission, that is 3 months after the onset of HF. Autopsy, which was performed to investigate the causes of rapid worsening HF, implied the impairment of ventricular function and coronary microcirculation dysfunction. We could diagnose CA immediately by using diagnostic tools, however, we recognized that there was the fulminant type in CA, and considered the insight from autopsy. 〈Learning objective: This case demonstrates a young patient with cardiac amyloidosis (CA) developed rapid worsening heart failure (RWHF), and then he died 1 month after diagnosis, that is 3 months after the onset of heart failure. This case deems to be a fulminant type in amyloid light-chain CA, and autopsy suggested the mechanisms of RWHF, which are the impairment of ventricular function and coronary microcirculation dysfunction.〉.

Hemodynamic Profiles and Their Prognostic Relevance in Cardiac Amyloidosis

This study sought to characterize cardiac amyloidosis (CA) patients with respect to hemodynamic parameters and asses their prognostic impact in different CA cohorts. Intracardiac and pulmonary arterial pressures (PAPs) are among the strongest predictors of outcomes in patients with heart failure (HF). Despite that, the hemodynamic profiles of patients with CA and their relation to prognosis have rarely been investigated. Invasive hemodynamic, clinical, and laboratory assessment, as well as cardiac magnetic resonance imaging were performed in our CA cohort. A total of 61 patients, 35 (57.4%) with wild-type transthyretin amyloidosis (ATTRwt) and 26 (42.6%) with light-chain amyloidosis (AL) were enrolled. ATTRwt patients had lower N-terminal prohormone of brain natriuretic peptide values and were less frequently in New York Heart Association class ≥ III. Intracardiac and PAPs were elevated, but hemodynamic parameters did not differ between CA groups. Whereas in ATTRwt, the median mean PAP (hazard ratio (HR): 1.130, p = 0.040) and pulmonary vascular resistance (HR: 1.010, p = 0.046) were independent predictors of outcome, no hemodynamic parameter was associated with outcome in the AL group. Cardiac ATTRwt and AL patients feature elevated intracardiac and PAPs and show similar hemodynamic profiles. However, hemodynamic parameters are of greater prognostic relevance in ATTRwt, potentially providing a new therapeutic target.