The Role of Scintigraphy with Bone Radiotracers in Cardiac Amyloidosis.

Cardiac amyloidosis (CA) is caused by the myocardial deposition of misfolded proteins, either amyloid transthyretin (ATTR) or immunoglobulin light chains (AL). The paradigm of this condition has transformed, since CA is increasingly recognized as a relatively prevalent cause of heart failure. Cardiac scintigraphy with bone tracers is the unique noninvasive technique able to confirm CA without performing tissue biopsy or advanced imaging tests. A moderate-to-intense myocardial uptake (Perugini grade ≥2) associated with the absence of a monoclonal component is greater than 99% specific for ATTR-CA, while AL-CA confirmation requires tissue biopsy.

Pathophysiology of Cardiac Amyloidosis.

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

Effects of sacubitril-valsartan on remodelling, fibrosis and mitochondria in a murine model of isoproterenol-induced left ventricular dysfunction.

BACKGROUND: Sacubitril/valsartan has been demonstrated to promote left ventricular (LV) reverse remodelling and improve outcomes in patients with heart failure (HF) with reduced ejection fraction (EF). Its molecular and tissue effects have not been fully elucidated yet, due to the paucity of preclinical studies, mostly based on ischaemic models. We aimed to evaluate the effects of sacubitril/valsartan on LV remodelling, myocardial fibrosis and mitochondrial biology in a murine model of non-ischaemic LV dysfunction. METHODS: Adult transgenic male mice with cardiac-specific hyperaldosteronism (AS mice) received subcutaneous isoproterenol injections to induce LV systolic dysfunction. After 7 days, mice were randomized to a 2-week treatment with saline (ISO-AS n = 15), valsartan (ISO + V n = 12) or sacubitril/valsartan (ISO + S/V n = 12). Echocardiography was performed at baseline, at day 7, and after each of the 2 weeks of treatment. After sacrifice at day 21, histological and immunochemical assays were performed. A control group of AS mice was also obtained (Ctrl-AS n = 8). RESULTS: Treatment with sacubitril/valsartan, but not with valsartan, induced a significant improvement in LVEF (p = 0.009 vs ISO-AS) and fractional shortening (p = 0.032 vs ISO-AS) after 2- week treatment. In both ISO + V and ISO + S/V groups, a trend toward reduction of the cardiac collagen 1/3 expression ratio was detected. ISO + V and ISO + S/V groups showed a significant recovery of mitochondrial morphology and inner membrane function meant for oxidative phosphorylation. CONCLUSION: In a murine model of non-ischaemic HF, sacubitril/valsartan proved to have beneficial effects on LV systolic function, and on cardiac energetics, by improving mitochondrial activity.

Wild-Type Transthyretin Cardiac Amyloidosis is Not Rare in Elderly Subjects: the CATCH Screening Study.

BACKGROUND: Wild-type transthyretin cardiac amyloidosis (ATTRwt-CA) affects older adults and is currently considered as a rare disorder. OBJECTIVE: We investigated for the first time the prevalence of ATTRwt-CA in elderly individuals from the general population. METHODS: General practitioners from Pisa, Italy, proposed a screening for ATTRwt-CA to all their patients aged 65-90 years, until 1,000 accepted. The following red flags were searched: interventricular septal thickness ≥12 mm, any echocardiographic, ECG or clinical hallmark of CA, or high sensitivity-troponin T ≥14 ng/L. Individuals with at least one red flag (n=346) were asked to undergo the search for a monoclonal protein and bone scintigraphy, and 216 accepted. RESULTS: Four patients received a non-invasive diagnosis of ATTRwt-CA. All complained of dyspnea on moderate effort. A woman and a man aged 79 and 85 years, respectively, showed an intense cardiac tracer uptake (grade 3), left ventricular (LV) wall thickening, grade 2 to 3 diastolic dysfunction, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) >1,000 ng/L. Two other patients (a man aged 74 years and a woman aged 83 years) showed a grade 2 uptake, an increased LV septal thickness, but preserved diastolic function, and NT-proBNP <300 ng/L. The prevalence of ATTR-CA in subjects ≥65 years was calculated as 0.46% (i.e., 4 out of the 870 subjects completing the screening, namely 654 not meeting the criteria for Step 2 and 216 progressing to Step 2). CONCLUSIONS: ATTRwt-CA is uncommon in elderly subjects from the general population, but more frequent than expected for a rare disease.

Wild-type transthyretin cardiac amyloidosis (ATTRwt-CA) is a heart condition mostly found in older adults. ATTRwt-CA is considered a rare disease, although no systematic screening have been performed yet. The study aimed to understand how common this disease is among the general population aged 65 to 90 years in Pisa, Italy. To do this, general practitioners offered screening for ATTRwt-CA to their patients within this age group. The initial step of the screening involved checking for certain warning signs (red flags), like abnormal thickness in a part of the heart called the interventricular septum, unusual heart function observed through various tests, or elevated levels of a specific heart protein. Out of 1,000 individuals who began the screening process, 346 showed at least one of these red flags and were further examined using bone scintigraphy (a type of imaging test) and tests for a specific protein related to this condition. Of these, 216 agreed to proceed with these additional tests. The results showed that four of these patients actually had ATTRwt-CA. Their conditions varied in severity, with some showing more intense signs of the disease on the heart scans, thicker heart walls, and higher levels of heart stress proteins. All four patients experienced mild difficulty in breathing during physical activity. Based on these findings, the study concluded that about 0.46% of elderly individuals in the general population might have ATTRwt-CA, indicating that the disease is somewhat more common in this age group than previously thought.

Case Report: Role of numerical simulations in the management of acute aortic syndromes.

Penetrating aortic ulcer (PAU) represents a subset of acute aortic syndromes characterized by high rupture risk and management challenges, particularly in elderly patients with significant comorbidities. This case report showcases a 75-year-old patient with a history of coronary artery bypass graft (CABG) and with multiple PAUs involving the aortic arch, deemed unfit for conventional open surgery. A branched aortic endograft with a pre-cannulated side component for the left subclavian artery (LSA) was employed to preserve the patency of the previous CABG. Two computational fluid dynamics (CFD) simulations and a morphological analysis were performed on the pre- and post-intervention aortic configurations to evaluate changes in flow rate and pressure drop at LSA level and differences in the lumen size. The results revealed a decrease in the flow rate equal to 2.38% after the intervention and an increase in pressure drop of 4.48 mmHg, while the maximum differences in LSA cross-sectional areas and diameters were 1.49 cm2 and 0.64 cm, respectively. Minimal alteration in LSA blood flow due to the chosen intervention approach confirmed the effectiveness of the selected unibody design endograft with LSA preservation, ensuring myocardial perfusion. Therefore, CFD simulations demonstrate to be a powerful tool to evaluate the hemodynamic consequences of interventions by accurately estimating the main fluid dynamic parameters.

Prevalence and clinical outcomes of isolated or combined moderate to severe mitral and tricuspid regurgitation in patients with cardiac amyloidosis.

AIMS: Evidence on the epidemiology and prognostic significance of mitral regurgitation (MR) and tricuspid regurgitation (TR) in patients with cardiac amyloidosis (CA) is scarce. METHODS AND RESULTS: Overall, 538 patients with either transthyretin (ATTR, n = 359) or immunoglobulin light-chain (AL, n = 179) CA were included at three Italian referral centres. Patients were stratified according to isolated or combined moderate/severe MR and TR. Overall, 240 patients (44.6%) had no significant MR/TR, 112 (20.8%) isolated MR, 66 (12.3%) isolated TR, and 120 (22.3%) combined MR/TR. The most common aetiologies were atrial functional MR, followed by primary infiltrative MR, and secondary TR due to right ventricular (RV) overload followed by atrial functional TR. Patients with isolated or combined MR/TR had a more frequent history of heart failure (HF) hospitalization and atrial fibrillation, worse symptoms, and higher levels of NT-proBNP as compared to those without MR/TR. They also presented more severe atrial enlargement, atrial peak longitudinal strain impairment, left ventricular (LV) and RV systolic dysfunction, and higher pulmonary artery systolic pressures. TR carried the most advanced features. After adjustment for age, sex, CA subtypes, laboratory, and echocardiographic markers of CA severity, isolated TR and combined MR/TR were independently associated with an increased risk of all-cause death or worsening HF events, compared to no significant MR/TR [adjusted HR 2.75 (1.78-4.24) and 2.31 (1.44-3.70), respectively]. CONCLUSION: In a large cohort of patients with CA, MR, and TR were common. Isolated TR and combined MR/TR were associated with worse prognosis regardless of CA aetiology, LV, and RV function, with TR carrying the highest risk.

Safety and efficacy of levosimendan in patients with cardiac amyloidosis.

BACKGROUND: Patients with cardiac amyloidosis (CA) often experience heart failure (HF) episodes. No evidence is available on inotropic therapy. This study aims to fill this gap by examining the safety and efficacy of levosimendan. METHODS: We retrieved all HF patients receiving ≥1 levosimendan infusion from 2013 to 2023. CA patients were matched with HF patients without CA (controls) based on sex, age, and left ventricular ejection fraction (LVEF). The response to levosimendan was measured as changes in daily urinary output, body weight, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and estimated glomerular filtration rate (eGFR). RESULTS: CA patients (median age 77 years, 73% men, 59% with ATTR-CA) and controls were compared. Levosimendan infusion was stopped because of hypotension in 2 cases with CA and (in 1 case) worsening renal function, and in 2 controls because of ventricular tachycardia episodes and (in 1 case) hypotension. CA patients showed a trend toward increased daily urinary output (p = 0.078) and a significant decrease in body weight (p < 0.001), without significant changes in NT-proBNP (p = 0.497) and eGFR (p = 0.732). Both CA patients and controls displayed similar changes in urinary output, weight, and eGFR, but NT-proBNP decreased more significantly among controls (p < 0.001). No differences were noted in rehospitalization rates, but CA patients experienced higher mortality at 6 and 12 months (p = 0.003 and p = 0.001, respectively). CONCLUSIONS: Levosimendan appears safe for CA patients needing inotropic support. The diuretic response and weight decrease during hospitalization were comparable between CA patients and matched HF patients, despite the greater mortality of CA patients after discharge.

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.

Characterization of Phenotypic Variability in Becker Muscular Dystrophy for Clinical Practice and Towards Trial Readiness: A Two-Years Follow up Study.

Background: Becker muscular dystrophy (BMD) is a dystrophinopathy due to in-frame mutations in the dystrophin gene (DMD) which determines a reduction of dystrophin at muscle level. BMD has a wide spectrum of clinical variability with different degrees of disability. Studies of natural history are needed also in view of up-coming clinical trials. Objectives: From an initial cohort of 32 BMD adult subjects, we present a detailed phenotypic characterization of 28 patients, then providing a description of their clinical natural history over the course of 12 months for 18 and 24 months for 13 of them. Methods: Each patient has been genetically characterized. Baseline, and 1-year and 2 years assessments included North Star Ambulatory Assessment (NSAA), timed function tests (time to climb and descend four stairs), 6-minute walk test (6MWT), Walton and Gardner-Medwin Scale and Medical Research Council (MRC) scale. Muscle magnetic resonance imaging (MRI) was acquired at baseline and in a subgroup of 9 patients after 24 months. Data on cardiac function (electrocardiogram, echocardiogram, and cardiac MRI) were also collected. Results and conclusions: Among the clinical heterogeneity, a more severe involvement is often observed in patients with 45-X del, with a disease progression over two years. The 6MWT appears sensitive to detect modification from baseline during follow up while no variation was observed by MRC testing. Muscle MRI of the lower limbs correlates with clinical parameters.Our study further highlights how the phenotypic variability of BMD adult patients makes it difficult to describe an uniform course and substantiates the need to identify predictive parameters and biomarkers to stratify patients.

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.

Sex differences in transthyretin cardiac amyloidosis.

Transthyretin cardiac amyloidosis (ATTR-CA) is a progressive disease characterized by the deposition of abnormal transthyretin protein fibrils in the heart, leading to cardiac dysfunction. Recent evidence suggests that sex differences may play a significant role in various steps of ATTR-CA, including clinical presentation, diagnostic challenges, disease progression, and treatment outcomes. ATTR-CA predominantly affects men, whereas women are older at presentation. Women generally present with a history of heart failure with preserved ejection fraction and/or carpal tunnel syndrome. When indexed, left ventricular (LV) wall thickness is equal, or even increased, than men. Women also have smaller LV cavities, more preserved ejection fractions, and apparently a slightly worse right ventricular and diastolic function. Given the under-representation on women in clinical trials, no data regarding sex influence on the treatment response are currently available. Finally, it seems there are no differences in overall prognosis, even if premenopausal women may have a certain level of myocardial protection. Genetic variations, environmental factors, and hormonal changes are considered as potential contributors to observed disparities. Understanding sex differences in ATTR-CA is vital for accurate diagnosis and management. By considering these differences, clinicians can improve diagnostic accuracy, tailor treatments, and optimize outcomes for both sexes with ATTR-CA.

Valvular heart disease in patients with cardiac amyloidosis.

Cardiac amyloidosis (CA) is an underdiagnosed condition caused by the deposition of misfolded proteins, namely immunoglobulin light chains and transthyretin, in the extracellular spaces of the heart. Any cardiovascular structure can be affected by amyloid infiltration, including the valves. Amyloid accumulation within the cardiac valves may lead to their structural and functional impairment, with a profound impact on patients' prognosis and quality of life. The most common forms of valvular disease in CA are aortic stenosis (AS), mitral regurgitation (MR), and tricuspid regurgitation (TR). CA and AS share similar risk factors, disease mechanisms, and remodeling patterns, which make their diagnosis particularly challenging. Patients with both CA and AS experience worse outcomes than CA or AS alone, and transcatheter aortic valve replacement may represent a useful therapeutic strategy in this population. Data on MR and TR are quite limited and mainly coming from case reports or small series. This review paper will summarize our current understanding on the epidemiology, disease mechanisms, echocardiographic features, clinical implications, and therapeutic options of AS, MR, and TR in patients with CA.

[Obstructive sleep apneas and cardiovascular diseases]. / Apnee ostruttive del sonno e malattie cardiovascolari.

Obstructive sleep apneas (OSA) are a breathing disorder characterized by recurrent apneas and hypopneas associated with complete or partial obstruction of the upper airways during sleep, resulting in disturbed sleep architecture, repeated hypoxemia and awakenings, and daytime sleepiness. OSA syndrome affects up to 34% of men and 17% of women in Western countries. Abnormalities in upper airway anatomy (frequently due to obesity), muscle tone, or neural control of breathing are the main causes. OSA is associated with impaired cognitive function and favors the onset of hypertension, being a major determinant of resistant hypertension, and may favor cardiovascular diseases (e.g., coronary artery disease and heart failure), thereby increasing mortality. Polysomnography and (cardio)-respiratory portable systems are used to diagnose and determine the severity of OSA. Management of OSA includes lifestyle modifications, such as weight loss and avoidance of supine sleep position, and continuous positive airway pressure. Mandibular advancement devices and upper airway surgery may also be appropriate for some patients. Hypoglossal nerve stimulation and pharmacological interventions are currently investigated to improve symptoms and outcomes.

Different Continuous Training Intensities Improve Echocardiographic Parameters, Quality of Life, and Functional Capacity in Heart Failure Patients with Reduced Ejection Fraction.

Background: Multiple comorbidities and physiological changes play a role in a range of heart failure conditions and influence the most effective approach to exercise-based rehabilitation. This research aimed to examine and compare the outcomes of continuous training at three different intensities, focusing on left ventricular (LV) remodeling, functional capacity, and quality of life among patients with heart failure with reduced ejection fraction (HFrEF). Methods: In this randomized control trial, a total of 60 male patients (average age: 54.33 ±2.35 years) with HFrEF were randomly allocated into three groups: 1) High-intensity continuous training group (HICT), 2) Moderate-intensity continuous training group (MICT), and 3) Low-intensity continuous training group (LICT). All the training was performed on a bicycle ergometer 3 times/week for 12 weeks. Echocardiographic parameters (left ventricular ejection fraction, left ventricular end-diastolic dimension, left ventricular end-systolic dimension, N-terminal pro-B-type natriuretic peptide (NT-proBNP), quality of life (Minnesota Living with Heart Failure Questionnaire), and functional capacity (6-minute walking test) were assessed before and the end of the study. Results: The HICT group demonstrated the greatest improvements in all measured variables when compared to the other two groups (P < 0.05). These findings were consistent across all measured outcomes. Conclusion: It was determined that HICT appears to yield the most favorable outcomes in enhancing echocardiographic measures, NT-proBNP levels, quality of life, and functional capacity among HFrEF patients.

Intact fibroblast growth factor 23 in heart failure with reduced and mildly reduced ejection fraction.

BACKGROUND: Fibroblast growth factor-23 (FGF23) has been associated to left ventricular (LV) hypertrophy and heart failure (HF) severity. We aimed to investigate the clinical correlates and prognostic value of intact FGF23 (iFGF23) in HF patients. METHODS: Patients with stable HF and left ventricular ejection fraction (LVEF) < 50% were prospectively enrolled, managed according to current recommendations and followed over time. iFGF23 was measured at baseline with a fully automated immuno-chemiluminescent assay. RESULTS: We enrolled 150 patients (82% males; median age 65 years). First, second, and third iFGF23 tertiles were < 35.2 pg/mL, 35.2-50.9 pg/mL, and > 50.9 pg/mL. LVEF decreased from the first iFGF23 tertile to the third tertile (p = 0.014). N-terminal pro-B-type natriuretic peptide (NT-proBNP) increased from the first to the third tertile (p = 0.001), while peak oxygen consumption decreased (p < 0.001). Thirty-five patients (23%) experienced the primary endpoint (all-cause death or HF hospitalization at 5 years), and 26 (17%) the secondary endpoint (all-cause death at 5 years). On multivariable analysis, iFGF23 independently predicted the primary endpoint on top of age, gender and LVEF (HR 4.6 [95% CI 2.1-10.3], p < 0.001), age, gender and eGFR (HR 4.1 [95% CI 1.6-10.3], p = 0.003), as well as age, gender and NT-proBNP (HR 3.6 [95% CI 1.6-8.2], p = 0.002). iFGF23 even reclassified patient risk on top of all the 3 models, with NRI values of 0.65 (95% CI 0.30-1.01), 0.55 (95% CI 0.25-0.88), and 0.60 (95% CI 0.24-0.96), respectively (both p < 0.001). CONCLUSIONS: Circulating iFGF23 is associated with disease severity and outcome in HF patients with reduced and mildly reduced ejection fraction.

[Critical reading of cardiovascular trials with neutral or negative findings]. / Approccio critico all'interpretazione dei trial cardiovascolari con risultati neutri o negativi.

Randomized controlled trials showing a significant benefit are met with enthusiasm because they may change the standard of care for patients who share the clinical and pathophysiologic characteristics of trial participants. Nonetheless, a well-designed and fully executed trial with neutral or negative findings also represents a critically important investigation deserving careful scientific scrutiny. In this paper we propose a 10-step approach to the interpretation of neutral or negative trials to exclude important methodological issues before concluding that the treatment really does not work. We will discuss this approach using the most classic trials of the past and some notable examples among superiority trials (mostly phase 3 trials) published over the last years.

[Central apneas and cardiovascular diseases]. / Apnee centrali e malattie cardiovascolari.

Central apneas (CA) and periodic breathing (PB) are the most common related breathing disorders in heart failure, being observed in up to 50% of patients. Once considered only a sleep-related phenomenon, actually CA/PB occur across the whole 24 h period and their presence in the awake patient even in the upright position and during physical effort has been associated with a worse clinical profile and a greater mortality. Chemoreflex activation, circulatory time delay and altered plant gain are the pathophysiological determinants. While the use of guideline-recommended medical and device treatment represents the first step in the management of CA in heart failure patients, no specific therapy has been demonstrated to reduce CA-related impact on mortality. In particular, the use of non-invasive ventilation has yielded contradictory results in the context of large-scale randomized clinical trials. The design and testing of therapies targeting the pathophysiological triggers of CA, such as chemoreflex sensitivity, may prove valuable in the next future.

Prognostic value of soluble ST2 in AL and TTR cardiac amyloidosis: a multicenter study.

Background: Both light-chain (AL) amyloidosis and transthyretin (ATTR) amyloidosis are types of cardiac amyloidosis (CA) that require accurate prognostic stratification to plan therapeutic strategies and follow-ups. Cardiac biomarkers, e.g., N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (Hs-cTnT), remain the cornerstone of the prognostic assessment. An increased level of soluble suppression of tumorigenesis-2 (sST2) is predictive of adverse events [all-cause death and heart failure (HF) hospitalizations] in patients with HF. This study aimed to evaluate the prognostic value of circulating sST2 levels in AL-CA and ATTR-CA. Methods: We carried out a multicenter study including 133 patients with AL-CA and 152 patients with ATTR-CA. During an elective outpatient visit for the diagnosis of CA, Mayo Clinic staging [NT-proBNP, Hs-cTnT, differential of free light chains (DFLCs)] and sST2 were assessed for all AL patients. Gillmore staging [including estimated glomerular filtration rate (eGFR), NT-proBNP] and Grogan staging (including NT-proBNP and Hs-cTnT) were assessed for TTR-CA patients. Results: The median age was 73 years [interquartile range (IQR) 61-81], and 53% were men. The endpoint was the composite of all-cause death or first HF-related hospitalization. The median follow-up was 20 months (IQR 3-34) in AL amyloidosis and 33 months (6-45) in TTR amyloidosis. The primary outcome occurred in 70 (53%) and 99 (65%) of AL and TTR patients, respectively. sST2 levels were higher in patients with AL-CA than in patients with ATTR-CA: 39 ng/L (26-80) vs. 32 ng/L (21-46), p < 0.001. In AL-CA, sST2 levels predicted the outcome regardless of the Mayo Clinic score (HR: 2.16, 95% CI: 1.17-3.99, p < 0.001). In TTR-CA, sST2 was not predictive of the outcome in multivariate models, including Gillmore staging and Grogan staging (HR: 1.17, CI: 95% 0.77-1.89, p = 0.55). Conclusion: sST2 level is a relevant predictor of death and HF hospitalization in AL cardiac amyloidosis and adds prognostic stratification on top of NT-proBNP, Hs cTnT, and DFLC.