¿Qué hay de nuevo en el diagnóstico de amiloidosis? / What is new in diagnosis of amyloidosis?

La amiloidosis siempre ha representado un desafío diagnóstico. En el año 2020, el Grupo de Estudio de Amiloidosis (GEA), confeccionó la Guía de Práctica Clínica para el Diagnóstico de Amiloidosis. Nuevas líneas de investigación se han desarrollado posteriormente. Esta revisión narrativa tiene como intención explorar el estado del arte en el diagnóstico de la amiloidosis. En pacientes con amiloidosis se recomienda la tipificación de la proteína mediante espectrometría de masa, técnica de difícil ejecución por requerir de microdisectores láser para la preparación de la muestra. Algunas publicaciones recientes proponen otros métodos para obtener la muestra de amiloide que se va a analizar, permitiendo prescindir de la microdisección. Por otra parte, en pacientes con Amiloidosis ATTR confirmada, la recomendación de secuenciar el gen amiloidogénico se encontraba destinada a los casos sospechosos de ATTR hereditaria (ATTRv,), pero actualmente esta se ha extendido a todos los pacientes sin importar la edad. En lo que respecta a los estudios complementarios orientados al diagnóstico de compromiso cardíaco, se ha propuesto el uso de la inteligencia artificial para su interpretación, permitiendo la detección temprana de la enfermedad y el correcto diagnóstico diferencial. Para el diagnóstico de neuropatía, las últimas publicaciones proponen el uso de la cadena ligera de neurofilamento sérica, que también podría resultar un indicador útil para seguimiento. Finalmente, con referencia a la amiloidosis AL, la comunidad científica se encuentra interesada en definir qué características determinan el carácter amiloidogénico de las cadenas livianas. La N-glicosilación de dichas proteínas impresiona ser uno de los determinantes en cuestión. (AU)

Amyloidosis has always represented a diagnostic challenge. In 2020, the Amyloidosis Study Group (ASG) developed the "Clinical Practice Guideline for the Diagnosis of Amyloidosis". New lines of research have subsequently emerged. This narrative review aims to explore the state of the art in the diagnosis of amyloidosis diagnosis. In patients with amyloidosis, protein typing by mass spectrometry is recommended, a technique hard to perform because it requires laser microdissection for sample preparation. Recent publications propose other methods to obtain the amyloid sample to be analyzed, making it possible to dispense with microdissection. On the other hand, in patients with confirmed TTR amyloidosis (aTTR), the recommendation to sequence the amyloidogenic gene was intended for suspected cases of hereditary aTTR but has now been extended to all patients regardless of age. (AU)

Manejo ambulatorio de pacientes con amiloidosis cardiaca por cadenas livianas / Outpatient management of patients with cardiac light chain amyloidosis

Resumen La amiloidosis primaria o de cadenas livianas (AL) es la forma más común de amiloidosis y se caracteriza por presentar una población clonal de células plasmáticas que producen una cadena ligera monoclonal de tipo lambda o kappa. En algunos sujetos, dicha cadena se deposita en forma de amiloide en los órganos y tejidos, dando lugar a manifestaciones clínicas, como proteinuria o síndrome nefrótico, miocardiopatía restrictiva y hepatomegalia. Aunque se considera una enfermedad rara, datos recientes sugieren que la amiloidosis cardíaca se subestima como una causa de enfermedades o síndromes cardíacos comunes. En la amiloidosis AL, tanto la respuesta hematológica como la de los órganos después del tratamiento son importantes para mejorar el resultado clínico, especialmente, si mejora la función cardíaca que es uno de los aspectos clave en el pronóstico de la amiloidosis AL. Se presenta el caso y la revisión de un paciente de sexo femenino, de 67 años de edad, que en la pesquisa diagnóstica de anemia e insuficiencia cardiaca (IC) se concluye en el diagnóstico de mieloma múltiple y amiloidosis cardiaca (AC) por depósito de cadenas livianas.

Abstract Primary or light chain (AL) amyloidosis is the most common form of amyloidosis and is characterized by a clonal population of plasma cells that produce a monoclonal lambda or kappa-type light chain, which in some subjects this chain is deposited as amyloid in the organs and tissues, giving rise to clinical manifestations such as proteinuria or nephrotic syndrome, restrictive cardiomyopathy and hepatomegaly. Although considered a rare disease, recent data suggest cardiac amyloidosis is underestimated as cause of common heart diseases or syndromes. In AL amyloidosis, both the hematologic and organ response after treatment, are important to improve clinical outcome. Especially if it improves cardiac function is one of the key aspects in the prognosis of AL amyloidosis. We present the case and review of a 67-year-old female patient, who in the investigation diagnoses anemia and heart failure concludes in the diagnosis of multiple myeloma and cardiac amyloidosis due to light chain deposition.

Cardiac magnetic resonance-feature tracking technique can assess cardiac function and prognosis in patients with myocardial amyloidosis / 南方医科大学学报

OBJECTIVE@#To quantitatively assess cardiac functions in patients with cardiac amyloidosis (CA) and hypertrophic cardiomyopathy (HCM) using cardiac magnetic resonance-feature tracking (CMR-FT) technique and evaluate the prognostic value of CMR-FT in patients with CA.@*METHODS@#We retrospectively collected the data from 31 CA patients with systemic amyloidosis confirmed by Congo red staining and serum immunohistochemistry after extracardiac tissue biopsy undergoing CMR at our hospital from March, 2013 to June, 2021.Thirty-one age and gender matched patients with asymmetric left ventricular wall hypertrophy and 31 healthy individuals without organic or functional heart disease served as the controls.Radial, circumferential and longitudinal strains and strain rates of the left ventricle at the global level and in each myocardial segment (basal, middle and apical) were obtained with CMR-FT technique and compared among the 3 groups.The predictive value of myocardial strains and strain rates for all-cause mortality in CA patients was analyzed using a stepwise COX regression model.@*RESULTS@#The left ventricular volume, myocardial mass, ejection fraction and cardiac output differed significantly among the groups (P < 0.05).Except for apical longitudinal strain, the global and segmental strains were all significantly lower in CA group than in HCM group (P < 0.05).The global and segmental strains were all significantly lower in CA group than in the healthy individuals (P < 0.05).The basal strain rates in the 3 directions were significantly lower in CA group than in the healthy individuals (P < 0.05), but the difference in apical strain rates was not statistically significant between the two groups.Multivariate stepwise COX analysis showed that troponin T (HR=1.05, 95%CI: 1.01-1.10, P=0.017) and middle peak diastolic circumferential strain rate (HR=6.87, 95%CI: 1.52-31.06, P=0.012) were strong predictors of death in CA patients.@*CONCLUSION@#Strain and strain rate parameters derived from CMR-FT based on cine sequences are new noninvasive imaging markers for assessing cardiac impairment in CA and cardiac function changes in HCM, and provide independent predictive information for all-cause mortality in CA patients.

Critical Management Strategies for Cardiovascular Involvementin Light Chain Amyloidosis / 罕见病研究

Light chain amyloidosis (AL) is a kind of rare disease. The misfolding of the light chain of monoclonal immunoglobulin forms amyloid substances and deposit in different tissues and organs, resulting in organ dysfunction. The heart involvement is represented as light chain cardiac amyloidosis (AL-CA), leading to heart failure, arrhythmia, myocardial infarction, valvular and pericardial diseases. Cardiac involvement is crucial for the risk stratification and prognosis prediction of patients with AL. The median survival time of AL-CA patients is 24 months and only 6 months for the heart failure patients. In recent years, the prognosis of patients with AL-CA has been significantly improved, thanks to the advancement in diagnosis & treatment strategies of cardiac amyloidosis, the milestone in the breakthroughs in targeted therapy of AL, and the improvement of coordinated multidisciplinary treatment. This paper focuses on the cardiovascular involvement of AL and briefly illustrates the pathogenesis, clinical manifestations, and the diagnosis and treatment of AL-CA.

Progress in New Therapies Targeting the Pathogenesis of Cardiomyopathywith Hypertrophic Phenotype / 罕见病研究

Hypertrophic cardiomyopathy (HCM) is cardiomyopathy with a clinical phenotype of cardiac hypertrophy. The etiology includes genetically defective encoding sarcomeres, congenital metabolic diseases such as lysosomal storage diseases, systemic amyloidosis such as transthyretin amyloidosis(ATTR), and Fabry disease. Previous therapies did not target the etiology and pathogenesis and therefore were less effective. In recent years, treatments targeting different mechanisms of myocardial hypertrophy have achieved good results. Mavacamten can reduce myocardial contractility by inhibiting ATP activity, thereby significantly improving left ventricular outflow tract(LVOT) obstruction, cardiac contractility, ventricular tension, and limitting myocardial damage. By inhibiting the dissociation of transthyretin(TTR) and subsequent formation and deposition of the amyloid fibril, tafamidis can reduce the mortality and morbidity of patients with transthyretin cardiac amyloidosis(ATTR-CA). Gene silencing and gene editing technology can reduce abnormal TTR levels. Synthesis of α-galactosidase A by gene recombination technology in vitro can effectively reduce left ventricular mass index(LVMi), improve cardiac function, reduce angina attacks and decrease mortality of Fabry disease.

Preliminary Study on Quantitative Evaluation of Myocardial Fibrosis by CardiacMagnetic Resonance in Patients with Light Chain Cardiac Amyloidosis / 罕见病研究

  Objective  Myocardial fibrosis is a potential mechanism of light-chain myocardial amyloidosis(AL-CA). This research aimed at exploring the correlation between multiparameter cardiac magnetic resonance (CMR) and myocardial fibrosis by relating the CMR myocardial tissue characteristics, the morphological and the functional parameters with gallium-68-labeledfibroblast activation protein inhibitor 04 positron emission tomography (68Ga-FAPI PET).  Methods  We gave the patients diagnosed with AL-CA in Peking Union Medical College Hospital from August to December 2021 the examinations of CMR and 68Ga-FAPI PET/CT. We recorded and analyzed the information on clinical manifestations and examinations of the patients.  Results  A total of 23 patients with AL-CA were included, 15 (65.2%)of which were male and the mean age was 58.3±6.5 years. Patients with high 68Ga-FAPI-04 uptake had shown growth in myocardial extracellular volume (ECV), significantly higher than those in the negative group (P=0.047). In addition, patients' myocardial ECV was positively correlated with myocardial FAPI uptake (r=0.628, P=0.001;r=0.727, P < 0.001;r=0.661, P=0.001). Patients in the positive group showd reduced left ventricular (LV) ejection fraction (EF)(P < 0.001).LVEF (r=-0.798, P < 0.001;r=-0.794, P < 0.001; r=-0.795, P < 0.001) and right ventricular (RV)EF (r=-0.735, P < 0.001;r=-0.739, P < 0.001;r=- 0.684, P < 0.001) showd negatively correlated with myocardial FAPI uptake, LV circumferential strain (r=0.668, P < 0.001;r=0.708, P < 0.001;r=0.705, P < 0.001), LV longitudinal strain (r=0.629, P=0.001;r=0.635, P=0.001; r=0.597, P=0.003), and RV longitudinal strain (r=0.575, P=0.004; r=0.792, P < 0.001;r=0.673, P < 0.001) were negatively correlated with myocardial FAPI uptake.  Conclusions  FAPI-related fibroblast activation is concurrent with CMR-related abnormal myocardial interstitial characteristics that leads to the decreased function of the myocardial movement. Patients with increased FAPI uptake present with increased ECV, decreased EF, and decreased strain with morphological abnormalities.

The Interpretation and Update of the Diagnosis Pathway of Chinese Expert Consensus on the Diagnosis and Treatment of Transthyretin Cardiac Amyoidosis / 罕见病研究

Transthyretin cardiac amyloidosis (ATTR-CA) is caused by the deposition of transthyretin(TTR) in the myocardial interstitium. Its clinical manifestations are mainly heart failure and arrhythmia, leading to poor life quality and low survival rate. Diagnosis is often delayed or missed due to the lack of disease awareness, the non-specific clinical symptom presentation of the disease, and inadequacy of non-invasive diagnostic methods and medications in the past. The recent availability of effective treatments makes the early recognition and diagnosis especially critical, because treatment is likely more effective earlier in the disease course. Therefore, it is crucial to establish a diagnosis and treatment strategy to facilitate the rapid and accurate identification of the disease. Based on the advances in research and experiences gained ATTR-CA, our team has developed a consensus on diagnosis and treatment for the disease. In this article, we interpret the key points and present the update of diagnostic process, providing clinicians with an overview of key aspects of ATTR-CA in China.

Value of nuclide scintigraphy in the diagnosis and prognosis of cardiac amyloidosis / 中南大学学报(医学版)

Amyloidosis is a local or systemic disease caused by the deposition of misfolded proteins outside the cell,with rapid progression,and dire prognosis.Common types of cardiac amyloidosis are monoclonal immunoglobulin light chain amyloidosis(AL-CA)and transthyretin cardiac amyloidosis(ATTR-CA).Nuclear medicine examinations can be accurate,rapid,and non-invasive to help diagnose diseases and can effectively predict the prognosis of patients with CA.Technetium(99Tcm)-labeled bisphosphonate imaging has been included in the consensus of experts and has become the first-line imaging method for the diagnosis of ATTR-CA.123I-metaiodoenzylguanidine(MIBG)as a norepinephrine analogue can effectively assess cardiac sympathetic innervation in patients with CA.Aβ-amyloid imaging agents such as 11C-pittsburgh compound B and 18F-flubetaben are expected to be new techniques for diagnosing AL-CA and incorporating them into cardiac staging systems for AL-CA patients in the future.New imaging agents such as 18F-NaF has been widely used in the diagnosis,treatment response monitoring,and prognosis assessment of CA.Summarizing the research value of nuclide imaging in CA may provide new ideas for clinical realization of early detection of CA and accurate assessment of disease prognosis.

Advancements in pharmacological therapy for transthyretin cardiac amyloidosis and its comorbidities / 中国药房

Transthyretin cardiac amyloidosis myocardiopathy （ATTR-CM） is an infiltrative cardiomyopathy characterized by the deposition of amyloidogenic material in the myocardial interstitium due to the misfolding of monomers following the dissociation of unstable transthyretin （TTR） tetramers. Previous treatments for ATTR-CM lacked specificity，primarily targeting symptomatic management of heart failure and arrhythmias. In recent years，researchers have developed two major classes of drugs addressing the pathogenesis of ATTR-CM. The first class stabilizes TTR tetramer structure （such as tafamidis and acoramidis）， while the second class interferes with TTR synthesis （such as patisiran）. Among these，tafamidis has been confirmed as the only currently effective treatment for ATTR-CM，while other drugs are still in clinical trial stages with limited clinical evidence. Concerning the management of comorbidities in ATTR-CM，treatment mainly focuses on common cardiac comorbidities （such as heart failure and arrhythmias）. Traditional drugs used to improve heart failure prognosis （such as β-blockers and renin-angiotensin- receptor blocker），have not demonstrated prognosis improvement in ATTR-CM patients and may even lead to adverse reactions. For ATTR-CM patients with concurrent atrial fibrillation，anticoagulation therapy is recommended to prevent thrombus formation，and amiodarone can be used for rhythm control. Despite significant advancements in pharmaceutical treatments for ATTR-CM，the overall prognosis remains poor，necessitating further research into the pathogenesis and target development to enhance the prognosis of ATTR-CM patients.

Left Ventricle Longitudinal Strain Parameters Are Effective for Differentiating Cardiac Amyloidosis from Primary Hypertensive Left Ventricular Hypertrophy / 中山大学学报(医学科学版)

ObjectiveTo clarify the value of the left ventricular longitudinal strain（LVLS）parameters in patients with cardiac amyloidosis （CA） and primary hypertension with left ventricular hypertrophy （HLVH）. MethodsForty-one patients confirmed with CA were selected and assigned to CA with hypertension group （n =14） and pure CA group （n=27） based on the initial diagnosis with or without hypertension. Twenty patients with primary hypertension-induced left ventricular hypertrophy （HLVH group） and twenty healthy controls were also selected， matching for gender， age， and body surface area. Clinical data， conventional echocardiography parameters were collected and LVLS parameters were measured. Within-group variations were compared among the four groups， and pairwise comparisons were conducted between groups. The sensitivity and specificity of each parameter in predicting CA were judged by the receiver operator characteristic （ROC） curvy in CA and HLVH patients with left ventricular ejection fraction （LVEF） preserved. ResultsAmong the conventional echocardiography parameters， LVEF and left ventricular end-diastolic diameter （LVEDD） were lower in the CA with hypertension group and pure CA group compared with the higher values in the HLVH group and control group. Whereas， left ventricular posterior wall thickness （LVPWT）， relative wall thickness （RWT）， and average E/e' were higher in the two CA groups compared with the HLVH group （all P＜0.05）.Among the LVLS parameters， Global longitudinal strain （GLS） was the worst in the CA with hypertension group so as pure CA group， modest in the HLVH group， and highest in the control group. On the contrary， relative longitudinal strain and ejection fraction strain ratio （EFSR） were the highest in the CA with hypertension group so as to pure CA group， modest in the HLVH group， and lowest in the control group （all P＜0.05）. ROC analysis showed that when LVEF was preserved， the absolute value of GLS less than 14.35% and EFSR higher than 4.28 could effectively distinguish CA from HLVH （all AUCs＞0.9，all P＜0.05）； meanwhile GLS showed high sensitivity（100%） and EFSR showed great specificity（95%）. There were not statistically significance in any parameter between CA with hypertension group and pure CA group（all P＞0.05）. ConclusionWhether CA was complicated with hypertension or not， there were statistically significance among routine echocardiography and LVLS parameters compared with HLVH. In particular， GLS and EFSR are accurate in predicting CA in patients with myocardial hypertrophy and preserved LVEF.