Genotype and Phenotype of Transthyretin Cardiac Amyloidosis: THAOS (Transthyretin Amyloid Outcome Survey)

Clinical and genetic profiles of patients with hereditary and wild-type transthyretin amyloidosis: the Transthyretin Cardiac Amyloidosis Registry in the state of São Paulo, Brazil (REACT-SP)

BACKGROUND

Transthyretin amyloidosis (ATTR) is a multisystem disease caused by the deposition of fibrillar protein in organs and tissues. ATTR genotypes and phenotypes are highly heterogeneous. We present data on physical signs and symptoms, cardiac and neurological assessments and genetic profile of patients enrolled in the Transthyretin Cardiac Amyloidosis Registry of the State of São Paulo, Brazil.

RESULTS

Six hundred-forty-four patients were enrolled, 505 with the variant form (ATTRv) and 139 with wild-type (ATTRwt). Eleven different mutations were detected, the most common being Val50Met (47.5%) and V142Ile (39.2%). Overall, more than half of the patients presented cardiac involvement, and the difference in this proportion between the ATTRv and ATTRwt groups was significant (43.9 vs. 89.9%; p < 0.001). The prevalence of the neurological phenotype also differed between ATTRv and ATTRwt (56.8 vs. 31.7%; p < 0.001). The mixed phenotype was found in 25.6% of the population, without a significant difference between ATTRv and ATTRwt groups. A group of patients remained asymptomatic (10.4%), with a lower proportion of asymptomatic ATTRwt patients.

CONCLUSIONS

This study details the clinical and genetic spectrum of patients with ATTR in São Paulo, Brazil. This preliminary analysis highlights the considerable phenotypic heterogeneity of neurological and cardiac manifestations in patients with variant and wild-type ATTR.

Salivary Gland Amyloidosis: Proteomic Identification and Clinicopathologic Characterization of 57 cases

Salivary gland amyloidosis is an uncommon diagnosis. Most studies have focused on minor salivary gland biopsies as a surrogate site for diagnosing systemic amyloidosis, while only few studies have investigated major salivary gland amyloidosis. We retrospectively identified 57 major and minor salivary gland amyloidosis cases typed using a proteomics-based method between 2010 and 2022. Frequency of amyloid types, clinicopathologic features, and distribution patterns of amyloid deposits were assessed. The indication for salivary gland biopsy/resection (known in 34 cases) included suspected amyloidosis (N=14; 41.2%), lesion/mass (N=12; 35.3%), swelling/enlargement (N=5; 14.7%), and rule out Sjogren syndrome (N=3; 8.8%). Concurrent pathology was reported in 16 cases, and included chronic sialadenitis (N=11), extranodal marginal zone lymphoma (N=3), plasma cell neoplasm (N=1), and pleomorphic adenoma (N=1). We identified 3 types of amyloidosis: immunoglobulin light chain/AL (N=47; 82.5%); immunoglobulin heavy chain/AH (N=1; 1.8%), and transthyretin/ATTR (N=9; 15.8%). The patterns of amyloid deposits (assessed in 35 cases) included: 1) Perivascular and/or periductal distribution (N=18; 51.4%); 2) Mass formation (N=9; 25.7%); 3) Stromal micronodule formation (N=7; 20.0%); and 4) Diffuse interstitial involvement (N=1; 2.9%). We also identified one case of AL amyloidosis localized to the major salivary gland, where only 6 other cases with adequate staging workup to exclude systemic amyloidosis were previously reported. In conclusion, salivary gland amyloidosis is an uncommon diagnosis but may be underrecognized due to low index of suspicion. Most cases of salivary gland amyloidosis are AL type, but a minority are ATTR. Therefore, proteomics-based typing remains essential for treatment and prognosis.

Carpal Tunnel Syndrome and Transthyretin Amyloidosis in the All of Us Research Program

OBJECTIVE

To evaluate the association of carpal tunnel syndrome (CTS) with incident heart failure and incident amyloidosis and to assess the risk of CTS in pathogenic TTR genetic variant carriers.

METHODS

This prospective cohort study included multiethnic US adults 18 years of age and older without prevalent heart failure and amyloidosis with available genotypic data from the All of Us Research Program. The primary outcomes were incident heart failure and incident amyloidosis. The association of incident heart failure and incident amyloidosis with CTS was assessed using multivariable adjusted Cox models accounting for age, sex, race and ethnicity, obesity, hypertension, diabetes, statin use, and smoking status.

RESULTS

Of the 166,987 individuals included, the median age was 54 (38 to 66) years; 105,279 (63.0%) were female, and 92,780 (55.6%) were non-Hispanic White individuals; CTS was identified in 12,407 (7.4%) individuals. Compared with individuals without CTS, the adjusted hazard ratio for incident heart failure was 1.13 (95% CI, 1.02 to 1.26) in individuals with CTS. The risk of amyloidosis was ∼3-fold higher (adjusted hazard ratio, 2.86; 95% CI, 1.71 to 4.77) in individuals with CTS compared with those without CTS. Individuals carrying a pathogenic TTR variant had an approximately 40% higher risk (adjusted hazard ratio, 1.38; 95% CI, 1.16 to 1.65) for development of CTS compared with noncarriers.

CONCLUSION

Cardiac amyloidosis screening programs may use CTS as a sentinel event and use genetic testing to identify individuals at a higher risk of TTR amyloidosis.

Hereditary transthyretin amyloidosis: a myriad of factors that influence phenotypic variability

Hereditary transthyretin-related amyloidosis (ATTRv amyloidosis) is a rare and progressively debilitating disease characterized by the deposition of transthyretin (TTR) amyloid fibrils in various organs and tissues, most commonly in the heart and peripheral nerves. This pathological deposition can lead to significant organ dysfunction and, ultimately, organ failure. ATTRv amyloidosis exhibits a broad range of clinical presentations, from purely neurological symptoms to purely cardiac manifestations, as well as mixed phenotypes which result from both neurological and cardiac implications. This wide phenotypical spectrum realistically challenges disease diagnosis and prognosis, especially in individuals without or with an unknown family history. Multiple factors are thought to contribute to this variability, including genetic, epigenetic, and even environmental influences. Understanding these factors is crucial, as they can significantly affect disease expression and progression. This review aims to summarize each of these contributing factors, to help elucidate the current knowledge on the phenotypical variability of ATTRv amyloidosis.

Cardiovascular Burden of the V142I Transthyretin Variant

Importance

Individual cohort studies concur that the amyloidogenic V142I variant of the transthyretin (TTR) gene, present in 3% to 4% of US Black individuals, increases heart failure (HF) and mortality risk. Precisely defining carrier risk across relevant clinical outcomes and estimating population burden of disease are important given established and emerging targeted treatments.

Objectives

To better define the natural history of disease in carriers across mid to late life, assess variant modifiers, and estimate cardiovascular burden to the US population.

Design, Setting, and Participants

A total of 23 338 self-reported Black participants initially free from HF were included in 4 large observational studies across the US (mean [SD], 15.5 [8.2] years of follow-up). Data analysis was performed between May 2023 and February 2024.

Exposure

V142I carrier status (n = 754, 3.2%).

Main Outcomes and Measures

Hospitalizations for HF (including subtypes of reduced and preserved ejection fraction) and all-cause mortality. Outcomes were analyzed by generating 10-year hazard ratios for each age between 50 and 90 years. Using actuarial methods, mean survival by carrier status was estimated and applied to the 2022 US population using US Census data.

Results

Among the 23 338 participants, the mean (SD) age at baseline was 62 (9) years and 76.7% were women. Ten-year carrier risk increased for HF hospitalization by age 63 years, predominantly driven by HF with reduced ejection fraction, and 10-year all-cause mortality risk increased by age 72 years. Only age (but not sex or other select variables) modified risk with the variant, with estimated reductions in longevity ranging from 1.9 years (95% CI, 0.6-3.1) at age 50 to 2.8 years (95% CI, 2.0-3.6) at age 81. Based on these data, 435 851 estimated US Black carriers between ages 50 and 95 years are projected to cumulatively lose 957 505 years of life (95% CI, 534 475-1 380 535) due to the variant.

Conclusions and Relevance

Among self-reported Black individuals, male and female V142I carriers faced similar and substantial risk for HF hospitalization, predominantly with reduced ejection fraction, and death, with steep age-dependent penetrance. Delineating the individual contributions of, and complex interplay among, the V142I variant, ancestry, the social construct of race, and biological or social determinants of health to cardiovascular disease merits further investigation.

Race and Socioeconomic Status Impact Diagnosis and Clinical Outcomes in Transthyretin Cardiac Amyloidosis

Background

Transthyretin amyloid cardiomyopathy (ATTR-CM) is associated with significant mortality. The Val122Ile variant, highly prevalent in Black patients, portends poorer survival compared with other ATTR-CM subtypes. Although Val122Ile is biologically more aggressive, the contribution of race and socioeconomic status (SES) to disease outcomes in patients with ATTR-CM is undefined.

Objectives

The aim of this study was to evaluate the impact of race and SES on clinical outcomes in patients with ATTR-CM.

Methods

Patients with ATTR-CM who received care at Johns Hopkins Hospital between 2006 and 2022 were included. SES was assessed using area deprivation index (ADI). Associations of race and ADI with heart failure (HF) hospitalization and/or death were measured using multivariable logistic or Cox proportional hazards models.

Results

Of 282 patients, 225 (80%) were men, and 129 (46%) were Black. Black vs White patients disproportionately constituted the highest ADI (most deprived) category (66% vs 28%; P = 0.004), and Black patients were more likely to have HF hospitalization or death over 5 years compared with White patients (log-rank P < 0.001). Among those with ADI >25, Black patients had a significantly greater hazard of HF hospitalization or death compared with White patients, independent of disease stage at diagnosis (HR: 2.77; 95% CI: 1.45-5.32; P = 0.002).

Conclusions

Black patients with low SES may be at greater risk for underdiagnosis and adverse outcomes compared with White patients. Ongoing efforts are needed to improve outcomes in this subset of patients with ATTR-CM.

Hereditary transthyretin cardiac amyloidosis proven by endomyocardial biopsy: a single-centre retrospective study and literature review

BACKGROUND

This study aimed to report the genotypes and phenotypes of hereditary transthyretin cardiac amyloidosis (hATTR-CA) in a Western Chinese cohort and review the genetic profiles of this disorder in the Chinese population.

METHODS

Transthyretin (TTR) gene sequencing of probands diagnosed with TTR cardiac amyloidosis and their relatives was performed at West China Hospital of Sichuan University from January 2018 to December 2021. All patients underwent endomyocardial biopsy for light and electron microscopy examinations. Clinical and essential examination materials were retrospectively collected and analysed.

RESULTS

TTR gene alteration was demonstrated in five probands and their two relatives. Three TTR variants were identified, namely, Ser23Asn, Glu54Leu and Thr60Ala. This study is the first to report Glu54Leu as pathogenic mutations in Chinese hATTR-CA patients. The Ser23Asn mutation was the most common mutation in this cohort. Five probands, including two males and three females, were all ethnic Han-Chinese. The median age at diagnosis and delay in diagnosis (interval from onset to diagnosis) was 56 years (range, 54-69 years) and 8 years (range, from 1 to 30 years), respectively. Three cases showed a defined family history of amyloidosis. Endomyocardial biopsies and TTR immunohistochemistry showed positive results in all patients. Two probands died 17.0 months and 21.0 months after diagnosis.

CONCLUSIONS

We identified one novel TTR variants causing hATTR-CA in the West Han Chinese population. To avoid misdiagnosis or delayed diagnosis of hATTR-CA, TTR genotypic screening and endomyocardial biopsy should be performed as soon as possible in cases with heightened clinical suspicion.

Circulating transthyretin and retinol binding protein 4 levels among middle-age V122I TTR carriers in the general population

BACKGROUND

Hereditary transthyretin cardiac amyloidosis (ATTRv-CA) has a long latency phase before clinical onset, creating a need to identify subclinical disease. We hypothesized circulating transthyretin (TTR) and retinol binding protein 4 (RBP4) levels would be associated with TTR carrier status and correlated with possible evidence of subclinical ATTRv-CA.

METHODS

TTR and RBP4 were measured in blood samples from V122I TTR carriers and age-, sex- and race-matched non-carrier controls (1:2 matching) among Dallas Heart Study participants (phases 1 (DHS-1) and 2 (DHS-2)). Multivariable linear regression models determined factors associated with TTR and RBP4.

RESULTS

There were 40 V122I TTR carriers in DHS-1 and 54 V122I TTR carriers in DHS-2. In DHS-1 and DHS-2, TTR was lower in V122I TTR carriers (p < .001 for both), and RBP4 in DHS-2 was lower in V122I TTR carriers than non-carriers (p = .002). Among V122I TTR carriers, TTR was negatively correlated with markers of kidney function, and limb lead voltage (p < .05 for both) and TTR and RBP4 were correlated with atrial volume in DHS-2 (p < .05).

CONCLUSIONS

V122I TTR carrier status is independently associated with lower TTR and RBP4 in comparison with non-carriers. These findings support the hypothesis that TTR and RBP4 may correlate with evidence of subclinical ATTRv-CA.

Real-World Effectiveness of High-Dose Tafamidis on Neurologic Disease Progression in Mixed-Phenotype Variant Transthyretin Amyloid Cardiomyopathy

INTRODUCTION

Transthyretin amyloidosis (ATTR) is a progressive, heterogeneous rare disease manifesting as ATTR polyneuropathy (ATTR-PN), ATTR cardiomyopathy (ATTR-CM), or a mixed phenotype. Tafamidis meglumine (20 mg po qd) is approved in some markets to delay neurologic progression in ATTR-PN, while high-dose tafamidis (80/61 mg po qd) is approved worldwide to reduce cardiovascular mortality and cardiovascular-related hospitalization in ATTR-CM. The objective of this study was to assess the real-world benefit of high-dose tafamidis for delaying neurologic progression in patients with mixed-phenotype variant ATTR-CM (ATTRv-CM).

METHODS

This exploratory, retrospective, observational cohort study evaluated anonymized electronic medical records and included adult patients with mixed-phenotype ATTRv-CM treated with high-dose tafamidis for at least 6 months. Neurologic assessments included the Medical Research Council (MRC) Scale for Muscle Strength, Neuropathy Impairment Score (NIS) muscle weakness subscale, and Polyneuropathy Disability (PND) instrument. Modified body mass index (mBMI) was also assessed.

RESULTS

Patients (N = 10) started tafamidis treatment an average of 3.8 months after diagnosis, with an average treatment duration of 20.8 months. Seven of 10 patients demonstrated normal muscle strength on the MRC scale throughout the study, and 9 of 10 patients had no decline in muscle strength during the post-treatment period. The NIS muscle weakness subscale score was ≤ 60 for all patients in the study at all time points, suggesting normal function to mild impairment. Six of 10 patients had no change in walking capacity as measured by the PND instrument at pre- and post-assessments, while one-third of patients had a decrease in PND stage (signaling improvement) from pre- to post-assessment. mBMI remained relatively stable throughout the study.

CONCLUSION

This is the first real-world study to demonstrate the potential value of high-dose tafamidis for delaying neurologic disease progression in patients with mixed-phenotype ATTRv-CM. The findings underscore the importance of multidisciplinary assessment for patients with ATTR amyloidosis.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT05139680.

Management of Arrhythmias and Conduction Disorders in Amyloid Cardiomyopathy

Cardiac amyloidosis, a condition characterized by abnormal protein deposition in the heart, leads to restrictive cardiomyopathy and is notably associated with an increased risk of arrhythmias and conduction disorders. This article reviews the current understanding and management strategies for these cardiac complications, with a focus on recent advancements and clinical challenges. The prevalence and impact of atrial arrhythmias, particularly atrial fibrillation, are examined, along with considerations for stroke risk and anticoagulation therapy. The article also addresses the complexities of managing rate and rhythm control, outlining the utility and limitations of pharmacological agents and interventions such as catheter ablation. Furthermore, it reviews the challenges in the treatment of ventricular arrhythmias, including the contentious use of implantable cardioverter-defibrillators for primary and secondary prevention. Individualized approaches, considering the unique characteristics of cardiac amyloidosis, are paramount. Continuous research and clinical exploration are essential to refine treatment strategies and improve outcomes in this challenging patient population.

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

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

Diagnostic Pitfall and Clinical Characteristics of Variant Versus Wild-Type Transthyretin Amyloid Cardiomyopathy in Asian Population: The Korean Nationwide Cohort Study

BACKGROUND

Transthyretin amyloidosis cardiomyopathy (ATTR-CM) is an under-recognized cause of heart failure (HF) with clinical phenotypes that vary across regions and genotypes. We sought to characterize the clinical characteristics of ATTR-CM in Asia.

METHODS

Data from a nationwide cohort of patients with ATTR-CM from six major tertiary centres in South Korea were analysed between 2010 and 2021. All patients underwent clinical evaluation, biochemical laboratory tests, echocardiography, and transthyretin (TTR) genotyping at the time of diagnosis. The study population comprised 105 Asian ATTR-CM patients (mean age: 69 years; male: 65.7%, wild-type ATTR-CM: 41.9%).

RESULTS

Among our cohort, 18% of the patients had a mean left ventricular (LV) wall thickness < 12 mm. The diagnosis of ATTR-CM increased notably during the study period (8 [7.6%] during 2010-2013 vs. 22 [21.0%] during 2014-2017 vs. 75 [71.4%] during 2018-2021). Although the duration between symptom onset and diagnosis did not differ, the proportion of patients with HF presenting mild symptoms increased during the study period (25% NYHA class I/II between 2010-2013 to 77% between 2018-2021). In contrast to other international registry data, male predominance was less prominent in wild-type ATTR-CM (68.2%). The distribution of TTR variants was also different from Western countries and from Japan. Asp38Ala was the most common mutation.

CONCLUSION

A nationwide cohort of ATTR-CM exhibited less male predominance, a proportion of patients without increased LV wall thickness, and distinct characteristics of genetic mutations, compared to cohorts in other parts of the world. Our results highlight the ethnic variation in ATTR-CM and may contribute to improving the screening process for ATTR-CM in the Asian population.

Cardiac amyloidosis is not a single disease: a multiparametric comparison between the light chain and transthyretin forms

AIMS

Systemic amyloidosis represents a heterogeneous group of diseases resulting from amyloid fibre deposition. The purpose of this study is to establish a differential diagnosis algorithm targeted towards the two most frequent subtypes of CA.

METHODS AND RESULTS

We prospectively included all consecutive patients with ATTR and AL evaluated between 2018 and 2022 in two centres in a score derivation cohort and a different validation sample. All patients had a complete clinical, biomarker, electrocardiographic, and imaging evaluation. Confirmation of the final diagnosis with amyloid typing was performed according to the current international recommendations. The study population included 81 patients divided into two groups: ATTR (group 1, n = 32: 28 variant and 4 wild type) and AL (group 2, n = 49). ATTR patients were younger (50.7 ± 13.9 vs. 60.2 ± 7.3 years, P = 0.0001), and significantly different in terms of NT-proBNP [ATTR: 1472.5 ng/L (97-4218.5) vs. AL 8024 ng/L (3058-14 069) P = 0.001], hs-cTn I [ATTR: 10 ng/L (4-20) vs. AL 78 ng/L (32-240), P = 0.0002], GFR [ATTR 95.4 mL/min (73.8-105.3) vs. AL: 68.4 mL/min (47.8-87.4) P = 0.003]. At similar left ventricular (LV) wall thickness and ejection fraction, the ATTR group had less frequently pericardial effusion (ATTR: 15% vs. AL: 33% P = 0.0027), better LV global longitudinal strain (ATTR: -13.1% ± 3.5 vs. AL: -9.1% ± 4.3 P = 0.04), RV strain (ATTR: -21.9% ± 6.2 vs. AL: -16.8% ± 6 P = 0.03) and better reservoir function of the LA strain (ATTR: 22% ± 12 vs. AL: 13.6% ± 7.8 P = 0.02). Cut-off points were calculated based on the Youden method. We attributed to 2 points for parameters having an AUC > 0.75 (NT-proBNP AUC 0.799; hs-cTnI AUC 0.87) and 1 point for GFR (AUC 0.749) and TTE parameters (GLS AUC 0.666; RV FWS AUC 0.649, LASr AUC 0.643). A score of equal or more than 4 points has been able to differentiate between AL and ATTR (sensitivity 80%, specificity 62%, AUC = 0.798). The differential diagnosis score system was applied to the validation cohort of 52 CA patients showing a sensitivity of 81% with specificity of 77%.

CONCLUSIONS

CA is a complex entity and requires extensive testing for a positive diagnosis. This study highlights a series of non-invasive checkpoints, which can be useful in guiding the decision-making process towards a more accurate and rapid differential diagnosis.

Characterization and natural history of different phenotypes in hereditary transthyretin amyloidosis: 40-year experience at a single Italian referral centre

AIMS

Hereditary transthyretin amyloidosis (ATTRv) is one of the leading aetiologies of systemic amyloidosis with more than 135 mutations described and a broad spectrum of clinical manifestations. We aimed to provide a systematic description of a population of individuals carrying pathogenic mutations of transthyretin (TTR) gene and to investigate the major clinical events during follow-up.

METHODS AND RESULTS

This was an observational, retrospective, cohort study including consecutive patients with mutations of TTR gene, admitted to a tertiary referral centre in Bologna, Italy, between 1984 and 2022. Three hundred twenty-five patients were included: 106 asymptomatic carriers, 49 cardiac phenotype, 49 neurological phenotype, and 121 mixed phenotype. Twenty-two different mutations were found, with Ile68Leu (41.8%), Val30Met (19%), and Glu89Gln (10%) being the most common. After a median follow-up of 51 months, 111 patients (38.3%) died and 9 (11.5%) of the 78 asymptomatic carriers developed ATTRv. Carriers had a prognosis comparable with healthy population, while no significant differences were seen among the three phenotypes adjusted by age. Age at diagnosis, New York Heart Association class III, left ventricular ejection fraction, modified polyneuropathy disability score IV, and disease-modifying therapy were independently associated with survival.

CONCLUSION

This study offers a wide and comprehensive overview of ATTRv from the point of view of a tertiary referral centre in Italy. Three main phenotypes can be identified (cardiac, neurological, and mixed) with specific clinical and instrumental features. Family screening programmes are essential to identify paucisymptomatic affected patients or unaffected carriers of the mutation, to be followed through the years. Lastly, disease-modifying therapy represents an evolving cornerstone of the management of ATTRv, with a great impact on mortality.

Treatment characteristics of patients with hereditary transthyretin amyloidosis: a cohort study

BACKGROUND

There are novel medications approved for the treatment of hereditary transthyretin amyloidosis (ATTRv), classified as transthyretin (TTR) stabilizers or gene silencers. While many patients may be on both classes of medications, there is no data available on the safety and efficacy of combination therapy.

OBJECTIVES

To describe ATTRv patient and TTR-targeted therapy characteristics in a US cohort, and compare outcomes with combination therapy versus monotherapy.

METHODS

We performed a retrospective cohort study with electronic health record data of patients with ATTRv seen at a single institution between January 2018 and December 2022. We collected data on symptomatology, gene mutation, disease severity, ATTRv treatment, hospitalizations, and mortality.

RESULTS

One hundred sixty-two patients with ATTRv were identified. The average age at diagnosis was 65 years. 86 patients (53%) had the V122I variant. 119 patients were symptomatic, of whom 103 were started on ATTRv-specific treatment. 41 patients (40%) had cardiomyopathy only, and 53 (51%) had a mixed phenotype of cardiomyopathy and neuropathy. 38 patients (37%) received therapy with both a gene silencer and protein stabilizer. 9 patients (15%) in the monotherapy group had two or more cardiac hospitalizations after starting treatment, compared to 3 patients (9%) on combination therapy (p=0.26). The adjusted hazard ratio of all-cause mortality for the patients on combination therapy compared to monotherapy was 0.37 (0.08-1.8, p=0.21).

CONCLUSIONS

While the efficacy is unproven, over one-third of patients with ATTRv are on both a stabilizer and a silencer. There were no safety issues for combination therapy. There was a trend towards improved hospitalizations and survival in patients in the combination group but this was not statistically significant. Larger studies with longer follow-up are necessary to determine benefit of combination therapy.

Disease features and management of cardiomyopathies in women

Over the last years, there has been a growing interest in the clinical manifestations and outcomes of cardiomyopathies in women. Peripartum cardiomyopathy is the only women-specific cardiomyopathy. In cardiomyopathies with X-linked transmission, women are not simply healthy carriers of the disorder, but can show a wide spectrum of clinical manifestations ranging from mild to severe manifestations because of heterogeneous patterns of X-chromosome inactivation. In mitochondrial disorders with a matrilinear transmission, cardiomyopathy is part of a systemic disorder affecting both men and women. Even some inherited cardiomyopathies with autosomal transmission display phenotypic and prognostic differences between men and women. Notably, female hormones seem to exert a protective role in hypertrophic cardiomyopathy (HCM) and variant transthyretin amyloidosis until the menopausal period. Women with cardiomyopathies holding high-risk features should be referred to a third-level center and evaluated on an individual basis. Cardiomyopathies can have a detrimental impact on pregnancy and childbirth because of the associated hemodynamic derangements. Genetic counselling and a tailored cardiological evaluation are essential to evaluate the likelihood of transmitting the disease to the children and the possibility of a prenatal or early post-natal diagnosis, as well as to estimate the risk associated with pregnancy and delivery, and the optimal management strategies.

The Cardiac Amyloidosis Registry Study (CARS): Rationale, Design and Methodology

BACKGROUND

CARS (Cardiac Amyloidosis Registry Study) is a multicenter registry established in 2019 that includes patients with transthyretin (ATTR, wild-type and variant) and light chain (AL) cardiac amyloidosis (CA) evaluated at major amyloidosis centers between 1997 and 2025. CARS aims to describe the natural history of CA with attention to clinical and diagnostic variables at the time of diagnosis, real-world treatment patterns, and associated outcomes of patients in a diverse cohort that is more representative of the at-risk population than that described in CA clinical trials.

METHODS AND RESULTS

This article describes the design and methodology of CARS, including procedures for data collection and preliminary results. As of February 2023, 20 centers in the United States enrolled 1415 patients, including 1155 (82%) with ATTR and 260 (18%) with AL CA. Among those with ATTR, wild-type is the most common ATTR (71%), and most of the 305 patients with variant ATTR have the p.V142I mutation (68%). A quarter of the total population identifies as Black. More individuals with AL are female (39%) compared to those with ATTR (13%).

CONCLUSIONS

CARS will answer crucial clinical questions about CA natural history and permit comparison of different therapeutics not possible through current clinical trials. Future international collaboration will further strengthen the validity of observations of this increasingly recognized condition.

The Diagnostic and Therapeutic Implications of Phenocopies and Mimics of Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a common myocardial disease defined by increased left ventricular wall thickness unexplained by loading conditions. HCM frequently is caused by pathogenic variants in sarcomeric protein genes, but several other syndromic, metabolic, infiltrative, and neuromuscular diseases can result in HCM phenocopies. This review summarizes the current understanding of these HCM mimics, highlighting their importance across the life course. The central role of a comprehensive, multiparametric diagnostic approach and the potential of precision medicine in tailoring treatment strategies are emphasized.

How Artificial Intelligence Can Enhance the Diagnosis of Cardiac Amyloidosis: A Review of Recent Advances and Challenges

Cardiac amyloidosis (CA) is an underdiagnosed form of infiltrative cardiomyopathy caused by abnormal amyloid fibrils deposited extracellularly in the myocardium and cardiac structures. There can be high variability in its clinical manifestations, and diagnosing CA requires expertise and often thorough evaluation; as such, the diagnosis of CA can be challenging and is often delayed. The application of artificial intelligence (AI) to different diagnostic modalities is rapidly expanding and transforming cardiovascular medicine. Advanced AI methods such as deep-learning convolutional neural networks (CNNs) may enhance the diagnostic process for CA by identifying patients at higher risk and potentially expediting the diagnosis of CA. In this review, we summarize the current state of AI applications to different diagnostic modalities used for the evaluation of CA, including their diagnostic and prognostic potential, and current challenges and limitations.

The association between prealbumin concentration at admission and mortality in elderly patients with hip fractures: a cohort study

Malnutrition is associated with complications and mortality in patients of hip fracture. Prealbumin may be more suitable than albumin to accurately predict the prognosis of hip fracture in elderly patients. We found that prealbumin concentration was nonlinearly associated with mortality in elderly patients with hip fracture, and an inflection point effect was observed.

OBJECTIVE

To evaluate the association between prealbumin concentration at admission and mortality in elderly patients with hip fractures.

METHODS

Elderly patients with hip fractures were screened between Jan 2015 and Sep 2019. Demographic and clinical characteristics of the patients were collected. Linear and nonlinear multivariate Cox regression models were used to identify the association between prealbumin concentration at admission and mortality. All analyses were performed using EmpowerStats and the R software.

RESULTS

This cohort study included 2387 patients who met the study criteria. The mean follow-up was 37.64 months. The prealbumin concentration was 162.67 ± 43.2 mg/L. Multivariate Cox regression showed that prealbumin concentration was associated with mortality in geriatric patients with hip fracture (hazard ratio [HR] = 0.95, 95% confidence intervals [CI]: 0.93-0.97, P < 0.0001). In addition, an inflection point effect was observed in the nonlinear association. The inflection point was 162.2 mg/L. If it is less than this inflection point, then every 10 mg/L increase in prealbumin was associated with a 7% reduction in the risk of death (HR = 0.93, 95%CI: 0.90-0.96, P < 0.0001). When greater than the inflection point, there was no difference in the risk of death (HR = 0.99, 95%CI: 0.95-1.03, P = 0.5127).

CONCLUSION

The prealbumin concentrations at admission were nonlinearly associated with long-term mortality in geriatric hip fractures, and 162.2 mg/L could be considered a prognostic factor of mortality risk.

Chest pain in a patient with transthyretin cardiac amyloidosis: A case report

Key Clinical Message

Patients with transthyretin cardiac amyloidosis (ATTR-CM) commonly present with dyspnea, fatigue, and edema. In our case, the main presentation was exertional angina, which was atypical in patients with ATTR-CM and should be paid more attention to.

Abstract

A 54-year-old woman was admitted with a complaint of exertional chest pain, and she had a history of hypertension. The results of the electrocardiogram and echocardiography revealed the clues of cardiac amyloidosis, and the patient was finally diagnosed with transthyretin cardiac amyloidosis, then she received tafamidis, and the symptoms improved significantly.

Race, Genotype, and Prognosis in Black Patients With Transthyretin Cardiac Amyloidosis

Previous studies suggest worse outcomes in patients with variant transthyretin cardiac amyloidosis (ATTR-CA) because of valine-to-isoleucine substitution at Position 122 (V122I) (ATTRv-CA) compared with patients with wild-type (WT) disease (ATTRwt-CA). Given V122I is almost exclusively found in Black patients, it is unclear if this is attributable to the biology of genotype or racial differences. Patients with ATTR-CA diagnosed between January 2001 and August 2021 were characterized into 3 categories: (1) White with ATTRwt-CA (White-WT); (2) Black with V122I ATTRv-CA (Black-V122I), and (3) Black with ATTRwt-CA (Black-WT). Event-free survival (composite of death, left ventricular assist device, or cardiac transplant) was evaluated using univariable and multivariable analyses over a median follow-up of 1.6 (0.7 to 2.90) years. Of 694 ATTR-CA patients, 502 (72%) were White-WT, 139 Black-V122I (20%), and 53 Black-WT (8%). Notably, 28% of Black patients with ATTR-CA had WT disease and not the V122I variant. Using multivariable modeling to adjust for several prognostic features, Black-V122I had higher risk of the composite adverse outcome compared with a grouped cohort of patients with WT disease (White-WT and Black-WT) (hazard ratio [HR] 1.82, confidence interval [CI] 1.30-2.56, p < 0.001). Furthermore, the Black cohort as a whole (Black-V122I and Black-WT) demonstrated greater risk of adverse outcomes compared with White-WT (HR 1.63, CI 1.19-2.24, p = 0.002). Black-V122I had greater risk of the primary end point compared with White-WT (HR 1.80, CI 1.27-2.56, p = 0.001). Black patients with ATTR-CA have worse event-free survival than White-WT despite risk adjustment. However, it remains unclear whether this is driven by differences in race or genotype given the smaller number of Black-WT patients. Approximately one-quarter of Black patients had WT, of which a greater proportion were female compared with White-WT.

Musculoskeletal co-morbidities in patients with transthyretin amyloid cardiomyopathy: a systematic review

The prevalence of transthyretin-associated amyloidosis cardiomyopathy (ATTR-CM) has grown because of newer non-invasive diagnosis tools. Detecting the presence of extra-cardiac ATTR manifestations such as musculoskeletal pathologies considered 'red flags', when there is minimal or non-cardiac clinical involvement is primordial to carry out an early diagnosis. The aim of this systematic review is to examine the prevalence of musculoskeletal, ATTR-deposition-related co-morbidities in patients already diagnosed with ATTR-CM, specifically carpal tunnel syndrome, ruptured biceps tendon, spinal stenosis, and trigger finger. We performed a systematic review using PRISMA guidelines. Inclusion criteria were all studies in English and Spanish language and participants had to be patients diagnosed with ATTR-CM, by any diagnostic method, with the musculoskeletal co-morbidities subject of this review. The quality of the studies was based on the Risk of Bias Tool. This systematic review included 22 studies for final analysis. Carpal tunnel syndrome is reported in 21 studies, brachial biceps tendon rupture is reported in three, and spinal stenosis in eight studies. No articles that accomplished all the inclusion criteria for trigger finger were found. Regarding to the quality of the studies, all of them were categorized as being of high and moderate quality. The frequent association between ATTR-CM and carpal tunnel syndrome, ruptured biceps tendon, and lumbar spinal is confirmed, and the onset of these co-morbidities usually precedes the diagnosis of by years. This association defines them as red flags that should be search proactively due to the current treatment possibilities and the severity of the presentation of cardiac amyloidosis.

Cardiac Amyloidosis Due to Transthyretin Protein: A Review

Importance

Systemic amyloidosis from transthyretin (ATTR) protein is the most common type of amyloidosis that causes cardiomyopathy.

Observations

Transthyretin (TTR) protein transports thyroxine (thyroid hormone) and retinol (vitamin A) and is synthesized predominantly by the liver. When the TTR protein misfolds, it can form amyloid fibrils that deposit in the heart causing heart failure, heart conduction block, or arrhythmia such as atrial fibrillation. The biological processes by which amyloid fibrils form are incompletely understood but are associated with aging and, in some patients, affected by inherited variants in the TTR genetic sequence. ATTR amyloidosis results from misfolded TTR protein deposition. ATTR can occur in association with normal TTR genetic sequence (wild-type ATTR) or with abnormal TTR genetic sequence (variant ATTR). Wild-type ATTR primarily manifests as cardiomyopathy while ATTR due to a genetic variant manifests as cardiomyopathy and/or polyneuropathy. Approximately 50 000 to 150 000 people in the US have heart failure due to ATTR amyloidosis. Without treatment, heart failure due to ATTR amyloidosis is associated with a median survival of approximately 5 years. More than 130 different inherited genetic variants in TTR exist. The most common genetic variant is Val122Ile (pV142I), an allele with an origin in West African countries, that is present in 3.4% of African American individuals in the US or approximately 1.5 million persons. The diagnosis can be made using serum free light chain assay and immunofixation electrophoresis to exclude light chain amyloidosis combined with cardiac nuclear scintigraphy to detect radiotracer uptake in a pattern consistent with amyloidosis. Loop diuretics, such as furosemide, torsemide, and bumetanide, are the primary treatment for fluid overload and symptomatic relief of patients with ATTR heart failure. An ATTR-directed therapy that inhibited misfolding of the TTR protein (tafamidis, a protein stabilizer), compared with placebo, reduced mortality from 42.9% to 29.5%, reduced hospitalizations from 0.7/year to 0.48/year, and was most effective when administered early in disease course.

Conclusions and Relevance

ATTR amyloidosis causes cardiomyopathy in up to approximately 150 000 people in the US and tafamidis is the only currently approved therapy. Tafamidis slowed progression of ATTR amyloidosis and improved survival and prevented hospitalization, compared with placebo, in people with ATTR-associated cardiomyopathy.

Patient-reported outcome measures for transthyretin cardiac amyloidosis: the ITALY study

BACKGROUND

Transthyretin cardiac amyloidosis (ATTR-CA) has a deep impact on the quality of life (QoL), yet no specific patient-reported outcome measures (PROMs) for ATTR-CA exist.

METHODS

The ITALY study involved 5 Italian referral centres (Pisa, Pavia, Ferrara, Florence, Messina) enrolling consecutive outpatients with ATTR-CA.

RESULTS

Two 30-item questionnaires were created for wild-type (wt) and variant (v) ATTR-CA. Scores ranged from 100 (best condition) to 0 (worst condition). Out of 140 patients enrolled (77% with ATTRwt-CA), 115 repeated the re-evaluation at 6 months. At baseline, only 30% of patients needed help to fill out the questionnaires. Among baseline variables, all KCCQ and SF-36 domains were univariate predictors of ITALY scores in ATTRwt-CA patients, with the KCCQ Symptom Summary score (beta coefficient 0.759), Social Limitations (0.781), and Overall summary score (0.786) being the strongest predictors. The SF-36 Emotional well-being score (0.608), the KCCQ Overall summary score (0.656), and the SF-36 Energy/fatigue score (0.669) were the strongest univariate predictors of ITALY scores in ATTRv-CA. Similar results were found at 6 months.

CONCLUSIONS

The ITALY questionnaires are the first specific PROMs for ATTRwt- and ATTRv-CA. Questionnaire completion is feasible. ITALY scores display close relationships with non-ATTR-specific measures of QoL.

Diagnosis and treatment of hereditary transthyretin amyloidosis with polyneuropathy in the United States: Recommendations from a panel of experts

Hereditary transthyretin (ATTRv; v for variant) amyloidosis is a rare, multisystem, progressive, and fatal disease in which polyneuropathy is a cardinal manifestation. Due to a lack of United States (US)-specific guidance on ATTRv amyloidosis with polyneuropathy, a panel of US-based expert clinicians convened to address identification, monitoring, and treatment of this disease. ATTRv amyloidosis with polyneuropathy should be suspected in unexplained progressive neuropathy, especially if associated with systemic symptoms or family history. The diagnosis is confirmed through genetic testing, biopsy, or cardiac technetium-based scintigraphy. Treatment should be initiated as soon as possible after diagnosis, with gene-silencing therapeutics recommended as a first-line option. Consensus is lacking on what represents "disease progression" during treatment; however, the aggressive natural history of this disease should be considered when evaluating the effectiveness of any therapy.

Clinical and Genotype Characteristics and Symptom Migration in Patients With Mixed Phenotype Transthyretin Amyloidosis from the Transthyretin Amyloidosis Outcomes Survey

INTRODUCTION

Transthyretin amyloidosis (ATTR amyloidosis) is primarily associated with a cardiac or neurologic phenotype, but a mixed phenotype is increasingly described.

METHODS

This study describes the mixed phenotype cohort in the Transthyretin Amyloidosis Outcomes Survey (THAOS). THAOS is an ongoing, longitudinal, observational survey of patients with ATTR amyloidosis, including both hereditary (ATTRv) and wild-type disease, and asymptomatic carriers of pathogenic transthyretin variants. Baseline characteristics of patients with a mixed phenotype (at enrollment or reclassified during follow-up) are described (data cutoff: January 4, 2022).

RESULTS

Approximately one-third of symptomatic patients (n = 1185/3542; 33.5%) were classified at enrollment or follow-up as mixed phenotype (median age, 66.5 years). Of those, 344 (29.0%) were reclassified to mixed phenotype within a median 1-2 years of follow-up. Most patients with mixed phenotype had ATTRv amyloidosis (75.7%). The most frequent genotypes were V30M (38.9%) and wild type (24.3%).

CONCLUSIONS

These THAOS data represent the largest analysis of a real-world mixed phenotype ATTR amyloidosis population to date and suggest that a mixed phenotype may be more prevalent than previously thought. Patients may also migrate from a primarily neurologic or cardiologic presentation to a mixed phenotype over time. These data reinforce the need for multidisciplinary evaluation at initial assessment and follow-up of all patients with ATTR amyloidosis.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00628745.

Outcomes of Octogenarian Patients Treated with Tafamidis for Transthyretin Amyloid Cardiomyopathy

Patients with transthyretin amyloid cardiomyopathy (ATTR-CM) benefit from disease-modifying agents such as tafamidis. However, the survival benefit of tafamidis in elderly patients (age ≥80 years) is not reported. This study aimed to assess the survival of patients with ATTR-CM aged 80 years and older who were treated with tafamidis compared with patients aged <80 years. We conducted a retrospective analysis of patients with ATTR-CM who underwent tafamidis treatment, aged 45 to 97 years at the time of diagnosis between January 1, 2008, and May 31, 2021. A total of 484 patients were included, with 208 in the ≥80 years group and 276 in the <80 years group. The cohort was followed up for mortality outcomes, and hazard ratios with 95% confidence intervals were calculated. After a median follow-up of 18.5 months, 72 deaths were recorded in the entire cohort. Kaplan-Meier curves showed no differences in survival probability between the 2 groups at 30 months (p for log-rank test = 0.76). The survival rates for patients aged ≥80 years who underwent treatment at 1, 2, 3, 4, and 5 years were 94.7%, 86.0%, 77.0%, 77.0%, and 38.5%, respectively. The corresponding rates for patients aged <80 years who underwent treatment were 93.2, 84.8, 74.4, 68.2, and 64.6%, respectively. In the multivariable analysis, the hazard ratio (95% confidence interval) of the mortality comparing treatment patients aged ≥80 years with those aged <80 years was 0.81 (0.41 to 1.61). In conclusion, tafamidis treatment is associated with similar reductions in mortality in older and younger patients with ATTR-CM.

Biochemical and biophysical properties of a rare TTRA81V mutation causing mild transthyretin amyloid cardiomyopathy

AIMS

We conducted a presentation on an 84-year-old male patient who has been diagnosed with TTRA81V (p. TTRA101V) hereditary transthyretin cardiac amyloidosis (hATTR-CM). In order to establish its pathogenicity, we extensively investigated the biochemical and biophysical properties of the condition.

METHODS AND RESULTS

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an increasingly acknowledged progressive infiltrative cardiomyopathy that leads to heart failure and potentially fatal arrhythmias. Gaining a comprehensive understanding of the biochemical and biophysical characteristics of genetically mutated TTR proteins serves as the fundamental cornerstone for delivering precise medical care to individuals affected by ATTR. Laboratory assessments indicated a brain natriuretic peptide of 200.12 ng/L (normal range: 0-100 ng/L) and high-sensitivity cardiac troponin I of 0.189 μg/L (normal range: 0-0.1 μg/L). Echocardiography identified left atrial enlargement, symmetrical left ventricular hypertrophy (16 mm septal and 16 mm posterior wall), and a left ventricular ejection fraction of 56%. Cardiac-enhanced magnetic resonance imaging revealed subendocardial late gadolinium enhancement. Tc-99m-PYP nuclear scintigraphy confirmed grade 3 myocardial uptake, showing an increased heart-to-contralateral ratio (H/CL = 2.33). Genetic testing revealed a heterozygous missense mutation in the TTR gene (c.302C>T), resulting in an alanine-to-valine residue change (p. Ala81Val, following the first 20 residues of signal sequence nomenclature). Biochemical analysis of this variant displayed compromised kinetic stability in both the TTRA81V:WT (wild-type) heterozygote protein (half-life, t1/2  = 21 h) and the TTRA81V homozygote protein (t1/2  = 17.5 h). The kinetic stability fell between that of the TTRWT (t1/2  = 42 h) and the early-onset TTRL55P mutation (t1/2  = 4.4 h), indicating the patient's late-onset condition. Kinetic stabilizers (Tafamidis, Diflunisal, and AG10) all exhibited the capacity to inhibit TTRA81V acid- and mechanical force-induced fibril formation, albeit less effectively than with TTRWT. Chromatographic assessment of the patient's serum TTR tetramers indicated a slightly lower concentration (3.0 μM) before oral administration of Tafamidis compared with the normal range (3.6-7.2 μM).

CONCLUSIONS

We identified a patient with hATTR-CM who possesses a rare TTRA81V mutation solely associated with cardiac complications. The slightly reduced kinetic stability of this mutation indicates its late-onset nature and contributes to the gradual progression of the disease.

Detection of TTR Amyloid in the Conjunctiva Using a Novel Fluorescent Ocular Tracer

Background

Transthyretin amyloidosis (ATTR) is a significant cause of cardiomyopathy and other morbidities in the elderly and Black Americans. ATTR can be treated with new disease-modifying therapies, but large shortfalls exist in its diagnosis. The objective of this study was to test whether TTR amyloid can be detected and imaged in the conjunctiva using a novel small-molecule fluorescent ocular tracer, with the implication that ATTR might be diagnosable by a simple eye examination.

Methods

Three approaches were used in this study. First, AMDX-9101 was incubated with in vitro aggregated TTR protein, and changes in its excitation and emission spectra were quantified. Second, a cadaver eye from a patient with familial amyloid polyneuropathy type II TTR mutation and a vitrectomy sample from an hATTR patient were incubated with AMDX-9101 and counterstained with Congo Red and antibodies to TTR to determine whether AMDX-9101 labels disease-related TTR amyloid deposits in human conjunctiva and eye. Last, imaging of in vitro aggregated TTR amyloid labeled with AMDX-9101 was tested in a porcine ex vivo model, using a widely available clinical ophthalmic imaging device.

Results

AMDX-9101 hyper-fluoresced in the presence of TTR amyloid in vitro, labeled TTR amyloid deposits in postmortem human conjunctiva and other ocular tissues and could be detected under the conjunctiva of a porcine eye using commercially available ophthalmic imaging equipment.

Conclusions

AMDX-9101 enabled detection of TTR amyloid in the conjunctiva, and the fluorescent binding signal can be visualized using commercially available ophthalmic imaging equipment.

Translational Relevance

AMDX-9101 detection of TTR amyloid may provide a potential new and noninvasive test for ATTR that could lead to earlier ATTR diagnosis, as well as facilitate development of new therapeutics.

Advances in the diagnosis and treatment of transthyretin amyloid cardiomyopathy

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underrecognized cause of heart failure (HF). ATTR-CM can lead to a number of cardiovascular manifestations including HF, rhythm disturbances, and valvular disease that ultimately limit quality of life and prognosis. Due to advances in diagnostic modalities and therapeutic options, the prevalence of ATTR-CM is rising. There are several classes of medications under active investigation, though most therapies are most efficacious if instituted early on in the disease course. As such, early clinical recognition and prompt diagnosis are crucial to improving disease related outcomes. In this review, we highlight clinical manifestations of ATTR-CM as well as contemporary diagnostic and treatment approaches to the disease.

Carpal tunnel syndrome

Median neuropathy at the wrist, commonly referred to as carpal tunnel syndrome (CTS), is the most common entrapment neuropathy. It is caused by chronic compression of the median nerve at the wrist within the space-limited carpal tunnel. Risk factors that contribute to the etiology of compression include female gender, obesity, work-related factors, and underlying medical conditions, such as hypothyroidism, pregnancy, and amyloidosis. The diagnosis is made on clinical grounds, although these can be confounded by anatomical variations. Electrodiagnostic studies, which are specific and sensitive in diagnosing CTS, support the diagnosis; however, a subgroup may present with normal results. The advent of imaging techniques, including ultrasound and MRI, further assists the diagnostic process. The management of CTS is divided into the nonsurgical approaches that include hand therapy, splinting and corticosteroid injection, and surgical decompression of the carpal tunnel. Although several surgical techniques have been developed, no one method is more effective than the other. Each of these management approaches are effective at providing symptom relief and are utilized at different severities of the condition. There is, however, a lack of consensus on standardized diagnostic criteria, as well as when and to whom to refer patients for surgery.

First Norwegian case of hereditary ATTR amyloidosis with a novel transthyretin variant

An earlier healthy 64-year-old man with previous surgery for bilateral carpal tunnel syndrome (CTS) in his 50s, presented with dyspnoea on exertion. Cardiac amyloidosis was suspected due to "red flag" signs and symptoms. Further investigations with scintigraphy and genetic testing confirmed the diagnosis of hereditary ATTR variant (ATTRv) amyloidosis. This is the first case report of ATTRv amyloidosis in a patient of Norwegian origin and is caused by the mutation E54A (p.E74A) in the transthyretin (TTR) gene. This mutation is previously not reported in international databases. Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underdiagnosed disease with a poor prognosis. Early recognition remains essential to afford the best treatment efficacy.

Recent Progress in the Development and Clinical Application of New Drugs for Transthyretin Cardiac Amyloidosis

ABSTRACT

Transthyretincardiac amyloidosis is a rare disease that has gained significant attention in recent years because of misfolding of transthyretin fibrils produced by the liver, leading to their deposition in the myocardium. The disease has an insidious onset, nonspecific clinical manifestations, and historically lacked effective drugs, making early diagnosis and treatment challenging. The survival time of patients largely depends on the extent of heart involvement at the time of diagnosis, and conventional treatments for cardiovascular disease do not provide significant benefits. Effective management of the disease requires treatment of its underlying cause. Orthotopic liver transplantation and combined hepato-heart transplantation have been clinically effective means of treating transthyretin cardiac amyloidosis mutants for many years. However, transplantation has many limitations in clinical practice. In recent years, the development of new drugs has brought new hope to patients. This review presents the latest advances in drug development and clinical application to provide a reference for clinicians managing transthyretin cardiac amyloidosis.

Comparison of cardiac involvement, extracardiac manifestations and outcomes between homozygote and heterozygote transthyretin p.Val142Ile (V122I) variant in patients with hereditary transthyretin amyloidosis: a cohort study

BACKGROUND

Hereditary transthyretin (ATTRv) p.Val142Ile (V122I) mutation is the most common inherited cause of cardiac amyloidosis and little is known about the phenotype and outcome of the rare homozygotic genotype. This study aimed to compare phenotypic characteristics and outcomes between heterozygous and homozygous patients with ATTRv V122I amyloidosis.

MATERIAL AND METHODS

This monocentric, observational, retrospective study conducted at the French National Referral Centre for Cardiac Amyloidosis (Henri Mondor Hospital, Créteil), described clinical, electrocardiographic, cardiac imaging features and prognostic data for patients with ATTRv V122I amyloidosis.

RESULTS

Among 185 ATTRv V122I patients identified, 161 were heterozygous and 24 were homozygous. The homozygous frequency was 13%. Onset occured significantly earlier in the homozygotes compared to heterozygotes with earlier median age at diagnosis (67[63-71] years vs 76[70-79] years, p < .001), age at first cardiac symptom (66[61-71] years vs 74[68-78] years, p < .001) and age at first extracardiac symptom (59[52-70] years vs 69[62-75] years, p = .003). Homozygous ATTRv V122I was also associated with greater disease burden with earlier events (death, transplant or hospitalisation for acute heart failure) compared with heterozygotes (71[67-74] vs 78[76-79] years, p = .018).

CONCLUSION

This rare, homozygous V122I cohort confirmed the earlier age of onset, death and cardiac events in this population.

A 15-year consolidated overview of data in over 6000 patients from the Transthyretin Amyloidosis Outcomes Survey (THAOS)

BACKGROUND

Transthyretin amyloidosis (ATTR amyloidosis) is a progressive, multisystemic, life-threatening disease resulting from the deposition of variant or wild-type (ATTRwt amyloidosis) transthyretin amyloid fibrils in various tissues and organs.

METHODS

Established in 2007, the Transthyretin Amyloidosis Outcomes Survey (THAOS) is the largest ongoing, global, longitudinal, observational study of patients with ATTR amyloidosis, including both hereditary and wild-type disease, and asymptomatic carriers of pathogenic TTR mutations. This analysis describes the baseline characteristics of symptomatic patients and asymptomatic gene carriers enrolled in THAOS since its inception in 2007 (data cutoff: August 1, 2022), providing a consolidated overview of 15-year data from the THAOS registry.

RESULTS

This analysis included 4428 symptomatic patients and 1707 asymptomatic gene carriers. The majority of symptomatic patients were male (70.8%) with a mean (standard deviation [SD]) age at symptom onset of 56.6 (17.9) years. Compared with the 14-year analysis, V30M remained the most prevalent genotype in Europe (62.2%), South America (78.6%), and Japan (74.2%) and ATTRwt remained most common in North America (56.2%). Relative to the 14-year analysis, there was an increase of mixed phenotype (from 16.6 to 24.5%) and a reduction of predominantly cardiac phenotype (from 40.7 to 31.9%). The proportion of patients with predominantly neurologic phenotype remained stable (from 40.1 to 38.7%). Asymptomatic gene carriers were 58.5% female with a mean age at enrollment of 41.9 years (SD 15.5).

CONCLUSIONS

This overview of > 6000 patients enrolled over 15 years in THAOS represents the largest registry analysis of ATTR amyloidosis to date and continues to emphasize the genotypic and phenotypic heterogeneity of the disease. Nearly a quarter of the symptomatic population within THAOS was mixed phenotype, underscoring the need for multidisciplinary management of ATTR amyloidosis.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00628745.

A simple ATTR-CM score to identify transthyretin amyloid cardiomyopathy burden in HFpEF patients

BACKGROUND

Transthyretin amyloid cardiomyopathy (ATTR-CM) is often found in patients with heart failure with preserved ejection fraction (HFpEF). However, the evidence regarding ATTR-CM and prognosis in HFpEF remains scarce. This study sought to determine whether the ATTR-CM burden was associated with clinical outcomes in HFpEF patients.

METHODS

We evaluated the associations of baseline ATTR-CM score with adverse outcomes in HFpEF patients from the TOPCAT trial using the Cox proportional hazards model or the competing risk regression model. The discriminatory ability of the ATTR-CM score was assessed using the area under the time-dependent receiver operating characteristic curve (AUC).

RESULTS

We included 870 HFpEF patients, 18.9% of which had an ATTR-CM score ≥6. Per 1 increment in the ATTR-CM score was significantly associated with an increased risk of the primary outcome (adjusted hazard ratio [HR] 1.19, 95% confidence interval [CI] 1.12-1.27) with an AUC of 0.652 (0.594-0.711), whereas patients with ATTR-CM score ≥6 presented higher risks of the primary outcome (adjusted HR 2.20, 95% CI 1.65-2.95). Similar results were observed toward the secondary outcomes.

CONCLUSIONS

The simple ATTR-CM score identified an 18.9% ATTR-CM burden in HFpEF patients, and a higher ATTR-CM burden might predict adverse outcomes with moderate discriminatory abilities in HFpEF.

Case Report: Transthyretin Glu54Leu-a rare mutation with predominant cardiac phenotype

We report two unrelated Bulgarian families with hereditary transthyretin (ATTR) amyloidosis due to a rare p.Glu74Leu (Glu54Leu) pathogenic variant found in seven individuals-three of them symptomatic. Only one family with the same variant and with a Swedish origin has been clinically described so far. Our patients are characterized by predominant cardiac involvement, very much similar to the Swedish patients. Although the initial complaint was bilateral carpal tunnel syndrome, advanced amyloid cardiomyopathy was found in two symptomatic carriers at diagnosis with heart failure manifestations. The neurological involvement was considered as mild, with mainly sensory signs and symptoms being present. We followed a non-biopsy algorithm to confirm the diagnosis. Tafamidis 61 mg has been initiated as the only approved disease modifying treatment for ATTR cardiomyopathy. Clinical stability in the absence of adverse events has been observed at follow up.

Detecting transthyretin amyloid cardiomyopathy (ATTR-CM) using machine learning: an evaluation of the performance of an algorithm in a UK setting

OBJECTIVE

The aim of this study was to evaluate the potential real-world application of a machine learning (ML) algorithm, developed and trained on heart failure (HF) cohorts in the USA, to detect patients with undiagnosed wild type cardiac amyloidosis (ATTRwt) in the UK.

DESIGN

In this retrospective observational study, anonymised, linked primary and secondary care data (Clinical Practice Research Datalink GOLD and Hospital Episode Statistics, respectively, were used to identify patients diagnosed with HF between 2009 and 2018 in the UK. International Classification of Diseases (ICD)-10 clinical modification codes were matched to equivalent Read (primary care) and ICD-10 WHO (secondary care) diagnosis codes used in the UK. In the absence of specific Read or ICD-10 WHO codes for ATTRwt, two proxy case definitions (definitive and possible cases) based on the degree of confidence that the contributing codes defined true ATTRwt cases were created using ML.

PRIMARY OUTCOME MEASURE

Algorithm performance was evaluated primarily using the area under the receiver operating curve (AUROC) by comparing the actual versus algorithm predicted case definitions at varying sensitivities and specificities.

RESULTS

The algorithm demonstrated strongest predictive ability when a combination of primary care and secondary care data were used (AUROC: 0.84 in definitive cohort and 0.86 in possible cohort). For primary care or secondary care data alone, performance ranged from 0.68 to 0.78.

CONCLUSION

The ML algorithm, despite being developed in a US population, was effective at identifying patients that may have ATTRwt in a UK setting. Its potential use in research and clinical care to aid identification of patients with undiagnosed ATTRwt, possibly enabling earlier diagnosis in the disease pathway, should be investigated.

Patisiran Treatment in Patients with Transthyretin Cardiac Amyloidosis

BACKGROUND

Transthyretin amyloidosis, also called ATTR amyloidosis, is associated with accumulation of ATTR amyloid deposits in the heart and commonly manifests as progressive cardiomyopathy. Patisiran, an RNA interference therapeutic agent, inhibits the production of hepatic transthyretin.

METHODS

In this phase 3, double-blind, randomized trial, we assigned patients with hereditary, also known as variant, or wild-type ATTR cardiac amyloidosis, in a 1:1 ratio, to receive patisiran (0.3 mg per kilogram of body weight) or placebo once every 3 weeks for 12 months. A hierarchical procedure was used to test the primary and three secondary end points. The primary end point was the change from baseline in the distance covered on the 6-minute walk test at 12 months. The first secondary end point was the change from baseline to month 12 in the Kansas City Cardiomyopathy Questionnaire-Overall Summary (KCCQ-OS) score (with higher scores indicating better health status). The second secondary end point was a composite of death from any cause, cardiovascular events, and change from baseline in the 6-minute walk test distance over 12 months. The third secondary end point was a composite of death from any cause, hospitalizations for any cause, and urgent heart failure visits over 12 months.

RESULTS

A total of 360 patients were randomly assigned to receive patisiran (181 patients) or placebo (179 patients). At month 12, the decline in the 6-minute walk distance was lower in the patisiran group than in the placebo group (Hodges-Lehmann estimate of median difference, 14.69 m; 95% confidence interval [CI], 0.69 to 28.69; P = 0.02); the KCCQ-OS score increased in the patisiran group and declined in the placebo group (least-squares mean difference, 3.7 points; 95% CI, 0.2 to 7.2; P = 0.04). Significant benefits were not observed for the second secondary end point. Infusion-related reactions, arthralgia, and muscle spasms occurred more often among patients in the patisiran group than among those in the placebo group.

CONCLUSIONS

In this trial, administration of patisiran over a period of 12 months resulted in preserved functional capacity in patients with ATTR cardiac amyloidosis. (Funded by Alnylam Pharmaceuticals; APOLLO-B ClinicalTrials.gov number, NCT03997383.).

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

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

Transthyretin amyloidosis cardiomyopathy in Greece: Clinical insights from the National Referral Center

BACKGROUND

Clinical characteristics and outcomes of patients with transthyretin amyloidosis cardiomyopathy (ATTR-CM) vary by region, necessitating the acquisition of country-specific evidence for proper management.

METHODS

This is an observational study including sequential patients presenting in the Amyloidosis Reference Center of Greece, from 01/2014 to 12/2022. ATTR-CM was diagnosed by positive scintigraphy and exclusion of light-chain amyloidosis or positive biopsy typing. Genetic testing was performed in all cases.

RESULTS

In total, 109 ATTR-CM patients were included (median age, 81 years) of which 15 carried TTR mutations (27% Val30Met). Most patients (82%) presented with heart failure and 59% with atrial fibrillation, while 10% had aortic stenosis. Importantly, 78 (71.6%) had clinically significant extracardiac manifestations (45% musculoskeletal disorder, 40% peripheral neuropathy, and 33% gastrointestinal symptoms). Sixty-five (60%) received disease-specific treatment with tafamidis. Estimated median survival was 48 months; advanced NYHA class, National Amyloidosis Center stage, eGFR<45 ml/kg/1.73 m2, NT-pro-BNP>5000 pg/mL were associated with worse survival, while tafamidis treatment was associated with improved survival in patients with IVS≥ 12 mm.

DISCUSSION

These are the first data describing the characteristics, management, and outcomes of patients with ATTR-CM in Greece, which could influence local guidelines.

Changes in amyloidosis phenotype over 11 years in a cardiac amyloidosis referral centre cohort in France

BACKGROUND

Early cardiac amyloidosis (CA) diagnosis enables patients to access effective treatments for better long-term outcomes, yet it remains under-recognised, misdiagnosed and inadequately managed.

AIM

To reduce diagnostic delays, we aimed to describe the epidemiological and clinical characteristics and changes over an 11-year period.

METHODS

This was a retrospective, observational cohort study of all patients referred to the Henri-Mondor Hospital for suspected CA.

RESULTS

Overall, 3194 patients were identified and 3022 were included and analysed. Our patients came from varied ethnic backgrounds, and more than half (55.2%) had confirmed CA. Over 11 years, referrals increased 4.4-fold, mostly from cardiologists. Notably, wild-type transthyretin amyloidosis (ATTRwt) became the predominant diagnosis, with referrals increasing 15-fold from 20 in 2010-2012 to 308 in 2019-2020. The number of amyloid light chain (AL) diagnoses increased, whilst variant transthyretin amyloidosis (ATTRv) numbers remained relatively stable. Concerning disease severity, AL patients presented more frequently with severe cardiac involvement whereas an increasing number of ATTRwt patients presented with National Amyloid Centre stage I (22.0% in 2013-2014 to 45.9% in 2019-2020). Lastly, among patients diagnosed with ATTRv in 2019-2020, 83.9% had ATTR Val122Ile cardiac phenotype.

CONCLUSIONS

This study shows that increasing cardiologist awareness and referrals have increased CA diagnoses. With improved awareness and non-invasive diagnostic techniques, more patients with ATTRwt with milder disease and more ATTRv Val122Ile mutations are being referred and diagnosed. Although more AL cases are being recognised, patients are diagnosed with severe cardiac involvement.

The patient pathway in ATTR-CM in Greece and how to improve it: A multidisciplinary perspective

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underdiagnosed disease associated with high mortality rates and the patient journey is characterized by increased complexities. Accurate and timely diagnosis and prompt initiation of disease-modifying treatment constitute the contemporary unmet need in ATTR-CM. ATTR-CM diagnosis is characterized by considerable delays and high rates of misdiagnosis. The majority of patients present themselves to primary care physicians, internists, and cardiologists, and many have undergone repeated medical evaluations before an accurate diagnosis has been made. The disease is diagnosed mainly after the development of heart failure symptoms, reflecting a long course of missed opportunities before diagnosis and disease-modifying treatment initiation. Early referral to experienced centers ensures prompt diagnosis and therapy. Early diagnosis, better care coordination, acceleration of digital transformation and reference networks, encouragement of patient engagement, and implementation of rare disease registries are the key pillars to improve the ATTR-CM patient pathway and achieve important benefits in ATTR-CM outcomes.