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.

Native myocardial T1 and right ventricular size by CMR predict outcome in systemic sclerosis-associated pulmonary hypertension.

OBJECTIVES: Measures of right heart size and function are prognostic in systemic sclerosis-associated pulmonary hypertension (SSc-PH), but the importance of myocardial tissue characterisation remains unclear. We aimed to investigate the predictive potential and interaction of cardiovascular magnetic resonance (CMR) myocardial tissue characterisation and right heart size and function in SSc-PH. METHODS: A retrospective, single-centre, observational study of 148 SSc-PH patients confirmed by right heart catheterization who underwent clinically-indicated CMR including native myocardial T1 and T2 mapping from 2016 to 2023 was performed. RESULTS: Sixty-six (45%) patients died during follow-up (median 3.5 years, range 0.1-7.3). Patients who died were older (65 vs 60 years, p= 0.035) with more dilated (RVEDVi and RVESVi, p< 0.001), hypertrophied (RVMi, p= 0.013) and impaired (RVEF, p< 0.001) right ventricles, more dilated right atria (RAi, p= 0.043) and higher native myocardial T1 (p< 0.001).After adjustment for age, RVESVi (p = 0.0023) and native T1 (p = 0.0024) were independent predictors of all-cause mortality. Both RVESVi and native T1 remained independently predictive after adjusting for age and PH subtype (RVESVi p < 0.001, T1 p = 0.0056). Optimal prognostic thresholds for RVESVi and native T1 were ≤38 mL/m2 and ≤1119 ms, respectively (p < 0.001). Patients with RVESVi ≤ 38 mL/m2 and native T1 ≤ 1119 ms had significantly better outcomes than all other combinations (p < 0.001). Furthermore, patients with RVESVi > 38mL/m2 and native T1 ≤ 1119 ms had significantly better survival than patients with RVESVi > 38mL/m2 and native T1 > 1119ms (p = 0.017). CONCLUSION: We identified prognostically relevant CMR metrics and thresholds for patients with SSc-PH. Assessing myocardial tissue characterisation alongside RV function confers added value in SSc-PH and may represent an additional treatment target.

Prognostic Value of a 6-Minute Walk Test in Patients With Transthyretin Cardiac Amyloidosis.

BACKGROUND: The 6-minute walk test (6MWT) represents a comprehensive functional assessment that is commonly used in patients with heart failure; however, data are lacking in patients with transthyretin cardiac amyloidosis (ATTR-CA). OBJECTIVES: This study aimed to assess the prognostic importance of the 6MWT in patients with ATTR-CA. METHODS: A retrospective analysis of patients diagnosed with ATTR-CA at the National Amyloidosis Centre who underwent a baseline 6MWT between 2011 and 2023 identified 2,141 patients, of whom 1,118 had follow-up at 1 year. RESULTS: The median baseline 6MWT distance was 347 m (Q1-Q3: 250-428 m) and analysis by quartiles demonstrated an increased death rate with each distance reduction (deaths per 100 person-years: 6.3 vs 9.2 vs 13.6 vs 19.0; log-rank P < 0.001). A 6MWT distance of <350 m was associated with a 2.2-fold higher risk of mortality (HR: 2.15; 95% CI: 1.85-2.50; P < 0.001), with a similar increased risk across National Amyloidosis Centre disease stages (P for interaction = 0.761) and genotypes (P for interaction = 0.172). An absolute (reduction of >35 m) and relative worsening (reduction of >5%) of 6MWT at 1 year was associated with an increased risk of mortality (HR: 1.80; 95% CI: 1.51-2.15; P < 0.001 and HR: 1.89; 95% CI: 1.59-2.24; P < 0.001, respectively), which was similar across the aforementioned subgroups. When combined with established measures of disease progression (N-terminal pro-B-type natriuretic peptide progression and outpatient diuretic intensification), each incremental increase in progression markers was associated with an increased death rate (deaths per 100 person-years: 7.6 vs 13.9 vs 22.4 vs 32.9; log-rank P < 0.001). CONCLUSIONS: The baseline 6MWT distance can refine risk stratification beyond traditional prognosticators. A worsening 6MWT distance can stratify disease progression and, when combined with established markers, identifies patients at the highest risk of mortality.

DEep LearnIng-based QuaNtification of epicardial adipose tissue predicts MACE in patients undergoing stress CMR.

BACKGROUND AND AIMS: This study investigated the additional prognostic value of epicardial adipose tissue (EAT) volume for major adverse cardiovascular events (MACE) in patients undergoing stress cardiac magnetic resonance (CMR) imaging. METHODS: 730 consecutive patients [mean age: 63 ± 10 years; 616 men] who underwent stress CMR for known or suspected coronary artery disease were randomly divided into derivation (n = 365) and validation (n = 365) cohorts. MACE was defined as non-fatal myocardial infarction and cardiac deaths. A deep learning algorithm was developed and trained to quantify EAT volume from CMR. EAT volume was adjusted for height (EAT volume index). A composite CMR-based risk score by Cox analysis of the risk of MACE was created. RESULTS: In the derivation cohort, 32 patients (8.7 %) developed MACE during a follow-up of 2103 days. Left ventricular ejection fraction (LVEF) < 35 % (HR 4.407 [95 % CI 1.903-10.202]; p<0.001), stress perfusion defect (HR 3.550 [95 % CI 1.765-7.138]; p<0.001), late gadolinium enhancement (LGE) (HR 4.428 [95%CI 1.822-10.759]; p = 0.001) and EAT volume index (HR 1.082 [95 % CI 1.045-1.120]; p<0.001) were independent predictors of MACE. In a multivariate Cox regression analysis, adding EAT volume index to a composite risk score including LVEF, stress perfusion defect and LGE provided additional value in MACE prediction, with a net reclassification improvement of 0.683 (95%CI, 0.336-1.03; p<0.001). The combined evaluation of risk score and EAT volume index showed a higher Harrel C statistic as compared to risk score (0.85 vs. 0.76; p<0.001) and EAT volume index alone (0.85 vs.0.74; p<0.001). These findings were confirmed in the validation cohort. CONCLUSIONS: In patients with clinically indicated stress CMR, fully automated EAT volume measured by deep learning can provide additional prognostic information on top of standard clinical and imaging parameters.

Stratifying Disease Progression in Patients With Cardiac ATTR Amyloidosis.

BACKGROUND: Transthyretin cardiac amyloidosis (ATTR-CA) is a progressive cardiomyopathy. The clinical course varies among individuals and there are no established measures to assess disease progression. OBJECTIVES: The goal of this study was to assess the prognostic importance of an increase in N-terminal pro-B-type natriuretic peptide (NT-proBNP) and outpatient diuretic intensification (ODI) as markers of disease progression in a large cohort of patients with ATTR-CA. METHODS: We evaluated landmark survival analysis based on worsening of NT-proBNP and requirement for ODI between time of diagnosis and a 1-year visit, and subsequent mortality in 2,275 patients with ATTR-CA from 7 specialist centers. The variables were developed in the National Amyloidosis Centre (NAC) cohort (n = 1,598) and validated in the external cohort from the remaining centers (n = 677). RESULTS: Between baseline and 1-year visits, 551 (34.5%) NAC patients and 204 (30.1%) patients in the external validation cohort experienced NT-proBNP progression (NT-proBNP increase >700 ng/L and >30%), which was associated with mortality (NAC cohort: HR: 1.82; 95% CI: 1.57-2.10; P < 0.001; validation cohort: HR: 1.75; 95% CI: 1.32-2.33; P < 0.001). At 1 year, 451 (28.2%) NAC patients and 301 (44.5%) patients in the external validation cohort experienced ODI, which was associated with mortality (NAC cohort: HR: 1.88; 95% CI: 1.62-2.18; P < 0.001; validation cohort: HR: 2.05; 95% CI: 1.53-2.74; P < 0.001). When compared with patients with a stable NT-proBNP and stable diuretic dose, a higher risk of mortality was observed in those experiencing either NT-proBNP progression or ODI (NAC cohort: HR: 1.93; 95% CI: 1.65-2.27; P < 0.001; validation cohort: HR: 1.94; 95% CI: 1.36-2.77; P < 0.001), and those experiencing both NT-proBNP progression and ODI (NAC cohort: HR: 2.98; 95% CI: 2.42-3.67; P < 0.001; validation cohort: HR: 3.23; 95% CI: 2.17-4.79; P < 0.001). CONCLUSIONS: NT-proBNP progression and ODI are frequent and consistently associated with an increased risk of mortality. Combining both variables produces a simple, universally applicable model that detects disease progression in ATTR-CA.

Cardiopulmonary Exercise Testing in Evaluating Transthyretin Amyloidosis.

Importance: Cardiopulmonary exercise testing (CPET) has an established role in the assessment of patients with heart failure. However, data are lacking in patients with transthyretin (ATTR) amyloidosis. Objective: To use CPET to characterize the spectrum of functional phenotypes in patients with ATTR amyloidosis and assess their association with the cardiac amyloid burden as well as the association between CPET parameters and prognosis. Design, Setting and Participants: This single-center study evaluated patients diagnosed with ATTR amyloidosis from May 2019 to September 2022 who underwent CPET at the National Amyloidosis Centre. Of 1045 patients approached, 506 were included and completed the study. Patients were excluded if they had an absolute contraindication to CPET or declined participation. The mean (SD) follow-up period was 22.4 (11.6) months. Main Outcomes and Measures: Comparison of CPET parameters across disease phenotypes (ATTR with cardiomyopathy [ATTR-CM], polyneuropathy, or both [ATTR-mixed]), differences in CPET parameters based on degree of amyloid infiltration (as measured by cardiovascular magnetic resonance [CMR] with extracellular volume mapping), and association between CPET parameters and prognosis. Results: Among the 506 patients with ATTR amyloidosis included in this study, the mean (SD) age was 73.5 (10.2) years, and 457 participants (90.3%) were male. Impairment in functional capacity was highly prevalent. Functional impairment in ATTR-CM and ATTR-mixed phenotypes (peak mean [SD] oxygen consumption [VO2], 14.5 [4.3] mL/kg/min and 15.7 [6.2] mL/kg/min, respectively) was observed alongside impairment in the oxygen pulse, with ventilatory efficiency highest in ATTR-CM (mean [SD] ventilatory efficiency/volume of carbon dioxide expired slope, 38.1 [8.6]). Chronotropic incompetence and exercise oscillatory ventilation (EOV) were highly prevalent across all phenotypes, with both the prevalence and severity being higher than in heart failure from different etiologies. Worsening of amyloid burden on CMR was associated with decline in multiple CPET parameters, although chronotropic response and EOV remained abnormal irrespective of amyloid burden. On multivariable Cox regression analysis, peak VO2 and peak systolic blood pressure (SBP) were independently associated with prognosis (peak VO2: hazard ratio, 0.89 [95% CI, 0.81-0.99; P = .03]; peak SBP: hazard ratio, 0.98 [95% CI, 0.97-0.99; P < .001]). Conclusions and Relevance: In this study, ATTR amyloidosis was characterized by distinct patterns of functional impairment between all disease phenotypes. A high prevalence of chronotropic incompetence, EOV, and ventilatory inefficiency were characteristic of this population. CPET parameters were associated with amyloid burden by CMR and with peak VO2, and SBP, which have been shown to be independent predictors of mortality. These findings suggest that CPET may be useful in characterizing distinct patterns of functional impairment across the spectrum of amyloid infiltration and predicting outcomes, and potentially offers a more comprehensive method of evaluating functional capacity for future prospective studies.

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.

Clinical and Prognostic Implications of Right Ventricular Uptake on Bone Scintigraphy in Transthyretin Amyloid Cardiomyopathy.

BACKGROUND: The extent of myocardial bone tracer uptake with technetium pyrophosphate, hydroxymethylene diphosphonate, and 3,3-diphosphono-1,2-propanodicarboxylate in transthyretin amyloid cardiomyopathy (ATTR-CM) might reflect cardiac amyloid burden and be associated with outcome. METHODS: Consecutive patients with ATTR-CM who underwent diagnostic bone tracer scintigraphy with acquisition of whole-body planar and cardiac single-photon emission computed tomography (SPECT) images from the National Amyloidosis Centre and 4 Italian centers were included. Cardiac uptake was defined according to the Perugini classification: 0=absent cardiac uptake; 1=mild uptake less than bone; 2=moderate uptake equal to bone; and 3=high uptake greater than bone. Extent of right ventricular (RV) uptake was defined as focal (basal segment of the RV free wall only) or diffuse (extending beyond basal segment) on the basis of SPECT imaging. The primary outcome was all-cause mortality. RESULTS: Among 1422 patients with ATTR-CM, RV uptake accompanying left ventricular uptake was identified by SPECT imaging in 100% of cases at diagnosis. Median follow-up in the whole cohort was 34 months (interquartile range, 21 to 50 months), and 494 patients died. By Kaplan-Meier analysis, diffuse RV uptake on SPECT imaging (n=936) was associated with higher all-cause mortality compared with focal (n=486) RV uptake (77.9% versus 22.1%; P<0.001), whereas Perugini grade was not associated with survival (P=0.27 in grade 2 versus grade 3). On multivariable analysis, after adjustment for age at diagnosis (hazard ratio [HR], 1.03 [95% CI, 1.02-1.04]; P<0.001), presence of the p.(V142I) TTR variant (HR, 1.42 [95% CI, 1.20-1.81]; P=0.004), National Amyloidosis Centre stage (each category, P<0.001), stroke volume index (HR, 0.99 [95% CI, 0.97-0.99]; P=0.043), E/e' (HR, 1.02 [95% CI, 1.007-1.03]; P=0.004), right atrial area index (HR, 1.05 [95% CI, 1.02-1.08]; P=0.001), and left ventricular global longitudinal strain (HR, 1.06 [95% CI, 1.03-1.09]; P<0.001), diffuse RV uptake on SPECT imaging (HR, 1.60 [95% CI, 1.26-2.04]; P<0.001) remained an independent predictor of all-cause mortality. The prognostic value of diffuse RV uptake was maintained across each National Amyloidosis Centre stage and in both wild-type and hereditary ATTR-CM (P<0.001 and P=0.02, respectively). CONCLUSIONS: Diffuse RV uptake of bone tracer on SPECT imaging is associated with poor outcomes in patients with ATTR-CM and is an independent prognostic marker at diagnosis.

Multiorgan Dysfunction and Associated Prognosis in Transthyretin Cardiac Amyloidosis.

BACKGROUND: Transthyretin cardiac amyloidosis (ATTR-CA) is a progressive and ultimately fatal cardiomyopathy. Biomarkers reflecting multiorgan dysfunction are of increasing importance in patients with heart failure; however, their significance in ATTR-CA remains largely unknown. The aims of this study were to characterize the multifaceted nature of ATTR-CA using blood biomarkers and assess the association between blood biomarkers and prognosis. METHODS AND RESULTS: This is a retrospective cohort study of 2566 consecutive patients diagnosed with ATTR-CA between 2007 and 2023. Anemia (39%), high urea (52%), hyperbilirubinemia (18%), increased alkaline phosphatase (16%), increased CRP (C-reactive protein; 27%), and increased troponin (98.2%) were common findings in the overall population, whereas hyponatremia (6%) and hypoalbuminemia (2%) were less common. These abnormalities were most common in patients with p.(V142I) hereditary ATTR-CA, and became more prevalent as the severity of cardiac disease increased. Multivariable Cox regression analysis demonstrated that anemia (hazard ratio [HR], 1.19 [95% CI, 1.04-1.37]; P=0.01), high urea (HR, 1.23 [95% CI, 1.04-1.45]; P=0.01), hyperbilirubinemia (HR, 1.32 [95% CI, 1.13-1.57; P=0.001), increased alkaline phosphatase (HR, 1.20 [95% CI, 1.01-1.42; P=0.04), hyponatremia (HR, 1.65 [95% CI, 1.28-2.11]; P<0.001), and troponin-T >56 ng/L (HR, 1.72 [95% CI, 1.46-2.03]; P<0.001) were all independently associated with mortality in the overall population. The association between biomarkers and mortality varied across the spectrum of genotypes and left ventricular ejection fraction, with anemia remining independently associated with mortality in p.(V142I) hereditary ATTR-CA (HR, 1.58 [95% CI, 1.17-2.12]; P=0.003) and in a subgroup of the overall population with a left ventricular ejection fraction ≤40% (HR, 1.39 [95% CI, 1.08-1.81]; P=0.01). CONCLUSIONS: Cardiac and noncardiac biomarker abnormalities were common and reflect the complex and multifaceted nature of ATTR-CA, with a wide range of biomarkers remaining independently associated with mortality. Clinical trials are needed to investigate whether biomarker abnormalities represent modifiable risk factors that if specifically targeted could improve outcomes.

Extending the reach of expert amyloidosis care: A feasibility study exploring the staged implementation of a UK amyloidosis network.

There has been an exponential increase in the diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CA). In response, the Midlands Amyloidosis Service was launched with the aim of providing patients with a timely diagnosis, remote expertise from the National Amyloidosis Centre and access to emerging transthyretin (TTR)-directed therapies. This was a descriptive study of a pilot hub-and-spoke model of delivering specialist amyloidosis care. Patients with suspected amyloidosis were referred from the wider Midlands region, and seen in a consultant-led multidisciplinary clinic. The diagnosis of ATTR-CA was established according to either the validated non-biopsy criteria or histological confirmation of ATTR deposits with imaging evidence of amyloid. Study endpoints were the volume of service provision and the time to diagnosis from the receipt of referral. Patients (n=173, age 75±2 years; male 72 %) were referred between 2019 and 2021. Eighty patients (46 %) were found to have cardiac amyloidosis, of whom 68 (85 %) had ATTR-CA. The median time from referral to diagnosis was 43 days. By removing the need for patients to travel to London, an average of 187 patient-miles was saved. Fifteen (9 %) patients with wild-type ATTR-CA received tafamidis under the Early Access to Medicine scheme; 10 (6 %) were enrolled into phase 3 clinical trials of RNA interference or antisense oligonucleotide therapies. Our results suggest that implementing a UK amyloidosis network appears feasible and would enhance equity of access to specialised amyloidosis healthcare for the increasing numbers of older patients found to have ATTR-CA.

Efficacy and Safety of Acoramidis in Transthyretin Amyloid Cardiomyopathy.

BACKGROUND: Transthyretin amyloid cardiomyopathy is characterized by the deposition of misfolded monomeric transthyretin (TTR) in the heart. Acoramidis is a high-affinity TTR stabilizer that acts to inhibit dissociation of tetrameric TTR and leads to more than 90% stabilization across the dosing interval as measured ex vivo. METHODS: In this phase 3, double-blind trial, we randomly assigned patients with transthyretin amyloid cardiomyopathy in a 2:1 ratio to receive acoramidis hydrochloride at a dose of 800 mg twice daily or matching placebo for 30 months. Efficacy was assessed in the patients who had an estimated glomerular filtration rate of at least 30 ml per minute per 1.73 m2 of body-surface area. The four-step primary hierarchical analysis included death from any cause, cardiovascular-related hospitalization, the change from baseline in the N-terminal pro-B-type natriuretic peptide (NT-proBNP) level, and the change from baseline in the 6-minute walk distance. We used the Finkelstein-Schoenfeld method to compare all potential pairs of patients within strata to generate a P value. Key secondary outcomes were death from any cause, the 6-minute walk distance, the score on the Kansas City Cardiomyopathy Questionnaire-Overall Summary, and the serum TTR level. RESULTS: A total of 632 patients underwent randomization. The primary analysis favored acoramidis over placebo (P<0.001); the corresponding win ratio was 1.8 (95% confidence interval [CI], 1.4 to 2.2), with 63.7% of pairwise comparisons favoring acoramidis and 35.9% favoring placebo. Together, death from any cause and cardiovascular-related hospitalization contributed more than half the wins and losses to the win ratio (58% of all pairwise comparisons); NT-proBNP pairwise comparisons yielded the highest ratio of wins to losses (23.3% vs. 7.0%). The overall incidence of adverse events was similar in the acoramidis group and the placebo group (98.1% and 97.6%, respectively); serious adverse events were reported in 54.6% and 64.9% of the patients. CONCLUSIONS: In patients with transthyretin amyloid cardiomyopathy, the receipt of acoramidis resulted in a significantly better four-step primary hierarchical outcome containing components of mortality, morbidity, and function than placebo. Adverse events were similar in the two groups. (Funded by BridgeBio Pharma; ATTRibute-CM ClinicalTrials.gov number, NCT03860935.).

Breakthrough advances enhancing care in ATTR amyloid cardiomyopathy.

Transthyretin amyloid cardiomyopathy (ATTR-CM) has been traditionally considered a rare and inexorably fatal condition. ATTR-CM now is an increasingly recognized cause of heart failure (HF) and mortality worldwide with effective pharmacological treatments. Advances in non-invasive diagnosis, coupled with the development of effective treatments, have transformed the diagnosis of ATTR-CM, which is now possible without recourse to endomyocardial biopsy in ≈70 % of cases. Many patients are now diagnosed at an earlier stage. Echocardiography and cardiac magnetic resonance have enabled identification of patients with possible ATTR-CM and more accurate prognostic stratification. Although radionuclide scintigraphy with 'bone' tracers has an established diagnostic value, the diagnostic performance of the bone tracers validated for non-invasive confirmation of ATTR-CM may not be equal. Characterising the wider clinical phenotype of patients with ATTR-CM has enabled identification of features with potential for earlier diagnosis such as carpal tunnel syndrome. Therapies able to slow or halt ATTR-CM progression and increase survival are now available and there is also evidence that patients may benefit from specific conventional HF medications. Cutting-edge research in the field of antibody-mediated removal of ATTR deposits compellingly suggest that ATTR-CM is a truly reversible disorder, bringing hope for patients even with advanced disease. A wide horizon of possibilities is unfolding and awaits discovery.

Myocardial perfusion in cardiac amyloidosis.

AIMS: Cardiac involvement is the main driver of clinical outcomes in systemic amyloidosis and preliminary studies support the hypothesis that myocardial ischaemia contributes to cellular damage. The aims of this study were to assess the presence and mechanisms of myocardial ischaemia using cardiovascular magnetic resonance (CMR) with multiparametric mapping and histopathological assessment. METHODS AND RESULTS: Ninety-three patients with cardiac amyloidosis (CA) (light-chain amyloidosis n = 42, transthyretin amyloidosis n = 51) and 97 without CA (three-vessel coronary disease [3VD] n = 47, unobstructed coronary arteries n = 26, healthy volunteers [HV] n = 24) underwent quantitative stress perfusion CMR with myocardial blood flow (MBF) mapping. Twenty-four myocardial biopsies and three explanted hearts with CA were analysed histopathologically. Stress MBF was severely reduced in patients with CA with lower values than patients with 3VD, unobstructed coronary arteries and HV (CA: 1.04 ± 0.51 ml/min/g, 3VD: 1.35 ± 0.50 ml/min/g, unobstructed coronary arteries: 2.92 ± 0.52 ml/min/g, HV: 2.91 ± 0.73 ml/min/g; CA vs. 3VD p = 0.011, CA vs. unobstructed coronary arteries p < 0.001, CA vs. HV p < 0.001). Myocardial perfusion abnormalities correlated with amyloid burden, systolic and diastolic function, structural parameters and blood biomarkers (p < 0.05). Biopsies demonstrated abnormal vascular endothelial growth factor staining in cardiomyocytes and endothelial cells, which may be related to hypoxia conditions. Amyloid infiltration in intramural arteries was associated with severe lumen reduction and severe reduction in capillary density. CONCLUSION: Cardiac amyloidosis is associated with severe inducible myocardial ischaemia demonstrable by histology and CMR stress perfusion mapping. Histological evaluation indicates a complex pathophysiology, where in addition to systolic and diastolic dysfunction, amyloid infiltration of the epicardial arteries and disruption and rarefaction of the capillaries play a role in contributing to myocardial ischaemia.

Complete responses in AL amyloidosis are unequal: the impact of free light chain mass spectrometry in AL amyloidosis.

ABSTRACT: Amyloidogenic serum free light chains (sFLCs) drive disease progression in AL amyloidosis. Matrix-assisted laser desorption/ionization time of flight mass spectrometry-based FLC assay (FLC-MS) has greater sensitivity than conventional sFLC assays allowing for the detection of serological residual disease. We report the utility of FLC-MS in a large series of patients with AL amyloidosis assessing the impact of FLC-MS negativity after treatment on overall survival (OS) and organ response rates. Serum samples were analyzed using FLC-MS at diagnosis and at 6 and 12 months after treatment. The impact of FLC-MS negativity over standard hematologic responses on survival and organ response was assessed. A total of 487 patients were included; 290 (59%) and 349 (71.5%) had cardiac and renal involvement, respectively. There was 100% concordance between the light chain (LC) fibril type and LC isotype identified by FLC-MS. At 6 and 12 months, 81 (16.6%) and 101 (20.7%) were FLC-MS negative. Of those achieving a conventional hematologic complete response (CR) at 6 and 12 months, 45 (27.7%) and 64 (39%) were FLC-MS negative. At 12 months, median OS for CR + FLC-MS negative was not reached vs 108 months in CR + FLC-MS positive (P = .024). At 12 months, 70% of patients with FLC-MS negativity (vs 50% FLC-MS positive) achieved a cardiac response (P = .015). In a multivariate analysis, FLC-MS negativity at 12 months was an independent predictor of better outcomes. FLC-MS can detect persistent monoclonal light chains in a significant proportion of patients in a conventional hematologic CR. FLC-MS assessment promises to be a new standard for response assessment in AL amyloidosis.

Deep phenotyping of p.(V142I)-associated variant transthyretin amyloid cardiomyopathy: Distinct from wild-type transthyretin amyloidosis?

AIMS: Transthyretin amyloid cardiomyopathy (ATTR-CM) is an increasingly recognized cause of heart failure. A total of 3-4% of individuals of African descent carry a TTR gene mutation encoding the p.(V142I) variant, a powerful risk factor for development of variant ATTR-CM (ATTRv-CM); this equates to 1.6 million carriers in the United States. We undertook deep phenotyping of p.(V142I)-ATTRv-CM and comparison with wild-type ATTR-CM (ATTRwt-CM). METHODS AND RESULTS: A retrospective study of 413 patients with p.(V142I) ATTRv-CM who attended the UK National Amyloidosis Centre (NAC) was conducted. Patients underwent evaluation at time of diagnosis, including clinical, echocardiography, and biomarker analysis; a subgroup had cardiac magnetic resonance (CMR) imaging. A total of 413 patients with ATTRwt-CM, matched for independent predictors of prognosis (age, NAC Stage, decade of first presentation), were used as a comparator group. At time of diagnosis, patients with ATTRv-CM had significant functional impairment by New York Heart Association classification (NHYA class ≥ III; 38%) and 6-min walk test distance (median 276 m). Median 5-year survival in ATTRv-CM patients was 31 versus 59 months in matched patients with ATTRwt-CM (p < 0.001). Patients with ATTRv-CM had significant impairment of functional parameters by echocardiography including biventricular impairment, high burden of regurgitant valvular disease and low cardiac output. Multivariable analysis revealed the prognostic importance of right ventricular dysfunction. CMR and histological analysis revealed myocyte atrophy and widespread myocardial infiltration in ATTRv-CM. CONCLUSION: p.(V142I)-ATTRv-CM has an aggressive phenotype characterized by myocyte loss and widespread myocardial infiltration which may account for frequent biventricular failure and poor prognosis in this ATTR-CM genotypic subgroup.

Albuminuria in transthyretin cardiac amyloidosis: Prevalence, progression and prognostic importance.

AIMS: Transthyretin cardiac amyloidosis (ATTR-CA) is an infiltrative cardiomyopathy that commonly presents with concomitant chronic kidney disease. Albuminuria is common in heart failure and associated with worse outcomes, but its prevalence and relationship to outcome in ATTR-CA remains unclear. METHODS AND RESULTS: A total of 1181 patients with ATTR-CA were studied (mean age 78.1 ± 7.9 years; 1022 [86.5%] male; median estimated glomerular filtration rate 59 ml/min/1.73m2 [interquartile range: 47-74]). Albuminuria was present in 563 (47.7%) patients (499 [88.6%] with microalbuminuria and 64 [11.4%] with macroalbuminuria). Patients with albuminuria had a more severe cardiac phenotype evidenced by higher serum cardiac biomarkers (median N-terminal pro-B-type natriuretic peptide [NT-proBNP]: 4027 ng/L [2173-6889] vs. 1851 ng/L [997-3209], p < 0.001; median troponin T: 69 ng/L [46-101] vs. 48 ng/L [34-68], p < 0.001) and worse echocardiographic indices of systolic (longitudinal strain: -10.0 ± 3.6% vs. -11.6 ± 3.8%, p < 0.001) and diastolic function (E/e': 17.5 ± 6.4 vs. 16.4 ± 6.7, p < 0.001) than those with a normal urinary albumin to creatinine ratio (UACR). Microalbuminuria and macroalbuminuria were independently associated with mortality in the overall population (hazard ratio [HR] 1.47, 95% confidence interval [CI] 1.13-1.92, p = 0.005 and HR 1.87, 95% CI 1.15-3.05, p = 0.012, respectively). In a subgroup of patients (n = 349) without concomitant hypertension, diabetes mellitus or chronic kidney disease, albuminuria was also associated with mortality (HR 2.98, 95% CI 1.72-5.17, p < 0.001). At 12 months, 330 patients had a repeat UACR measurement; those in whom UACR increased by 30% or more (n = 148, 44.8%) had an increased risk of mortality (HR 1.84, 95% CI 1.06-3.19, p = 0.030). CONCLUSIONS: Albuminuria is common in patients with ATTR-CA, and more prevalent in those with a more severe cardiac phenotype. Albuminuria at diagnosis and a significant increase in UACR during follow-up are associated with mortality.

Standardising Care and Treatment of Transthyretin Amyloid Cardiomyopathy.

Transthyretin cardiac amyloidosis (ATTR-CA) has been traditionally considered a rare and inexorably fatal condition. ATTR-CA now is an increasingly recognised cause of heart failure and mortality worldwide with effective pharmacological treatments. Advances in non-invasive diagnosis, coupled with the development of effective treatments, have transformed the diagnosis of ATTR-CA, which is now possible without recourse to endomyocardial biopsy in around 70% of cases. Many patients are now diagnosed at an earlier stage. Echocardiography and cardiac magnetic resonance have enabled identification of patients with possible ATTR-CA and more accurate prognostic stratification. Therapies able to slow or halt ATTR-CA progression and increase survival are now available and there is also evidence that patients may benefit from specific conventional heart failure medications. A wide horizon of possibilities is unfolding and awaits discovery.

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.).