Transthyretin Cardiac Amyloidosis Research Articles

PREVALENCE OF WILD–TYPE TRANSTHYRETIN CARDIAC AMYLOIDOSIS IN ELDERLY SUBJECTS FROM THE GENERAL POPULATION

Abstract 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 dyspnoea 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 has a prevalence of 0.46% in elderly subjects from the general population.

Deep Learning-Enabled Quantification of 99mTc-Pyrophosphate SPECT/CT for Cardiac Amyloidosis.

Transthyretin cardiac amyloidosis (ATTR CA) is increasingly recognized as a cause of heart failure in older patients, with 99mTc-pyrophosphate imaging frequently used to establish the diagnosis. Visual interpretation of SPECT images is the gold standard for interpretation but is inherently subjective. Manual quantitation of SPECT myocardial 99mTc-pyrophosphate activity is time-consuming and not performed clinically. We evaluated a deep learning approach for fully automated volumetric quantitation of 99mTc-pyrophosphate using segmentation of coregistered anatomic structures from CT attenuation maps. Methods: Patients who underwent SPECT/CT 99mTc-pyrophosphate imaging for suspected ATTR CA were included. Diagnosis of ATTR CA was determined using standard criteria. Cardiac chambers and myocardium were segmented from CT attenuation maps using a foundational deep learning model and then applied to attenuation-corrected SPECT images to quantify radiotracer activity. We evaluated the diagnostic accuracy of target-to-background ratio (TBR), cardiac pyrophosphate activity (CPA), and volume of involvement (VOI) using the area under the receiver operating characteristic curve (AUC). We then evaluated associations with the composite outcome of cardiovascular death or heart failure hospitalization. Results: In total, 299 patients were included (median age, 76 y), with ATTR CA diagnosed in 83 (27.8%) patients. CPA (AUC, 0.989; 95% CI, 0.974-1.00) and VOI (AUC, 0.988; 95% CI, 0.973-1.00) had the highest prediction performance for ATTR CA. The next highest AUC was for TBR (AUC, 0.979; 95% CI, 0.964-0.995). The AUC for CPA was significantly higher than that for heart-to-contralateral ratio (AUC, 0.975; 95% CI, 0.952-0.998; P = 0.046). Twenty-three patients with ATTR CA experienced cardiovascular death or heart failure hospitalization. All methods for establishing TBR, CPA, and VOI were associated with an increased risk of events after adjustment for age, with hazard ratios ranging from 1.41 to 1.84 per SD increase. Conclusion: Deep learning segmentation of coregistered CT attenuation maps is not affected by the pattern of radiotracer uptake and allows for fully automatic quantification of hot-spot SPECT imaging such as 99mTc-pyrophosphate. This approach can be used to accurately identify patients with ATTR CA and may play a role in risk prediction.

Changes in the diagnostic trajectory of transthyretin cardiac amyloidosis over six years.

Awareness of transthyretin amyloid cardiomyopathy (ATTR-CM) has increased over the years due to diagnostic and therapeutic developments. Timely initiation of novel disease-modifying treatments improves both morbidity and mortality, which underlines the necessity for a prompt diagnosis. Nevertheless, early diagnosis of ATTR-CM remains challenging. This is a retrospective observational cohort study of patients diagnosed with ATTR-CM. Between 2016 and 2023, 87 patients were diagnosed with cardiac amyloidosis of which 65 (75%) patients with ATTR-CM and 22 (25%) patients with light chain amyloidosis. This study included 65 ATTR-CM patients (mean age 77 ± 7years; 86% male) of whom 59 (91%) with wild-type ATTR-CM (ATTRwt) and six (9%) with variant ATTR-CM. We observed a surge in ATTR-CM diagnoses from 3 patients/year (2016-2020) to 16 patients/year (2021-2023), driven by ATTRwt. Nevertheless, the interval between the onset of heart failure symptoms and ATTR-CM diagnosis has not changed significantly (2016-2020 27.3months [18.6-62.4]; 2021-2023 30.0months [8.6-57.2]; p = 0.546), driven by time to referral. Red flags for ATTR-CM preceded diagnosis by several years: left ventricular hypertrophy (79%, 5.8years [3.3-7.0]) and carpal tunnel syndrome (49%, 6.8years [2.3-12.1]). Despite the presence of typical red flags, symptom-to-diagnosis duration has remained similar driven by time to referral. Improved recognition of red flags for ATTR-CM could reduce the time to diagnosis and improve overall recognition.

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

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). This study aimed to assess the prognostic importance of the 6MWT in patients with ATTR-CA. 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. The median baseline 6MWT distance was 347m (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<350m 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). 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.

Incidental Finding of Transthyretin Cardiac Amyloidosis During Coronary Artery Bypass Grafting

Incidental Finding of Transthyretin Cardiac Amyloidosis During Coronary Artery Bypass Grafting

A case report on Transthyretin Cardiac Amyloidosis

Introduction : Cardiac amyloidosis is due to the extracellular accumulation of insoluble fibrillar proteins which progressively alter the function of the myocardium. The prognosis depends on the severity of the cardiac involvement. Transthyretin cardiac amyloidosis (TTR) is the most common. It can be wild-type (ATTRwt), hereditary (ATTRv) or senile (wild TTR). The diagnosis of cardiac amyloidosis has greatly improved in the last decade and is based on multimodal imaging, mainly echocardiography and bone scintigraphy. Case Report: We report the case of a male patient hospitalized for heart failure due to transthyretin cardiac amyloidosis. Conclusion: Recognition of this pathology is essential because cardiological management is specific and conventional treatments for heart failure can be harmful. Only specific treatments can slow down or stop the infiltration process.

Oxidative damage in immunoglobulin light chain and transthyretin cardiac amyloidosis – a closer look

Heart failure is a progressive disease, representing a growing cause of morbidity, hospitalization, and mortality. An increasingly common type of heart failure with preserved ejection fraction (HFpEF) is an immunoglobulin light chain and transthyretin cardiac amyloidosis, in the pathophysiology of which oxidative damage appears to exert a strong impact. Reactive oxygen and nitrogen species have physiological signaling functions, but their overaccumulation, as in cardiac amyloidosis, leads to cardiomyocyte damage and apoptosis, and to cardiac hypertrophy and fibrosis. Moreover, such pathological processes worsen the redox damage with the perpetuation of an inflammatory state, in a vicious cycle. Here, the role of oxidative damage in the transthyretin and immunoglobulin light chain cardiac amyloidosis, the underlying pathogenic mechanisms, the therapeutic implications, and possible future strategies are reviewed.

Bilateral Multiple Fractures Obstruct Quantitation of 99mTc-Pyrophosphate Imaging for Cardiac Amyloidosis.

A 57-year-old woman who had persistent symptoms of transthyretin cardiac amyloidosis underwent 99mTc-pyrophosphate (99mTc-PYP) scintigraphy. The 99mTc-PYP planar and SPECT/CT fusion image showed diffuse myocardial uptake and multiple fractures of the sternum and ribs. These fractures interfered with semiquantitative scores of 99mTc-PYP uptake, leading to false positive in 99mTc-PYP imaging.

Prognostic Value of Standard Heart Failure Medication in Patients with Cardiac Transthyretin Amyloidosis.

Introduction: Cardiac transthyretin amyloidosis (ATTR) is a progressive, fatal disease leading to heart failure due to accumulation of amyloid fibrils in the interstitial space and may occur as a hereditary (ATTRv) or wild-type (ATTRwt) form. Guidelines recommend the use of ACE inhibitors (ACEis) and beta-blockers (BBs) as heart failure therapy (HFT) in all patients with symptomatic heart failure and reduced ejection fraction, independent of the underlying etiology. However, the prognostic benefit of ACEis and BBs in ATTR has not been elucidated in detail yet. We thus sought to retrospectively investigate the outcome of patients with ATTRwt or ATTRv under HFT. Methods: Medical records of 403 patients with cardiac ATTR (ATTRwt: n = 268, ATTRv: n = 135) were screened for long-term medication as well as clinical, laboratory, electrocardiographic and echocardiographic data. Patients were assessed between 2005 and 2020 at the University Hospital Heidelberg. Kaplan-Meier analysis was used to analyze potential differences in survival among different subgroups. Results: The mean follow-up was 28 months. In total, 43 patients (32%) with ATTRv and 140 patients (52%) with ATTRwt received HFT. Survival was significantly shorter in patients receiving HFT in ATTRv (46 vs. 83 months, p = 0.0007) vs. non-HFT. A significantly better survival was observed in patients with comorbidities (coronary artery disease, arterial hypertension) and HFT among ATTRwt patients (p = 0.004). No significant differences in survival were observed in the other subgroups. Conclusions: Survival analysis revealed a potential benefit of HFT in patients with ATTRwt and cardiac comorbidities such as coronary artery disease and/or arterial hypertension. In contrast, HFT should be used with caution in patients with ATTRv.

Determinants of health status in older patients with transthyretin cardiac amyloidosis: a prospective cohort study.

Whether, and to what extent, frailty and other geriatric domains are linked to health status in patients with transthyretin cardiac amyloidosis (ATTR-CA) is unknown. To determine the association of frailty with health status [defined by the Kansas City Cardiomyopathy Questionnaire (KCCQ)] in patients with ATTR-CA. Consecutive ATTR-CA patients undergoing cardiovascular assessment at a tertiary care clinic from September 2021 to September 2023 were invited to participate. KCCQ, frailty and social environment were recorded. Frailty was assessed using the modified Frailty Index (mFI), mapping 11 variables from the Canadian Study of Health and Aging (frailty ≥0.36). Of 168 screened ATTR-CA patients, 138 [83% men, median age of 79 (75-84) years] were enrolled in the study. Median KCCQ was 66 (50-75). wtATTR-CA was the most prevalent form (N=113, 81.9%). The most frequent cardiac variant was Ile68Leu (17/25 individuals with vATTR-CA). Twenty (14.5%) patients were considered frail, and prevalence of overt disability was 6.5%. At multivariable linear regression analysis, factors associated with worsening KCCQ were age at evaluation, the mFI, NYHA Class, and NAC Score. Gender, ATTR-CA type, phenotype, and LVEF were not associated with health status. In older patients diagnosed with ATTR-CA, frailty, symptoms, and disease severity were associated with KCCQ. Functional status is a determinant of quality of life and health status in older individuals with a main diagnosis of ATTR-CA. Future research may provide more in-depth knowledge on the association of frailty in patients with ATTR-CA with respect to quality of life and prognosis.

A Novel Approach to Cardiac Magnetic Resonance Scar Characterization in Patients Affected by Cardiac Amyloidosis: A Pilot Study.

Background and Objectives: Cardiac magnetic resonance (CMR) imaging has become an essential instrument in the study of cardiomyopathies; it has recently been integrated into the diagnostic workflow for cardiac amyloidosis (CA) with remarkable results. An additional emerging role is the stratification of the arrhythmogenic risk by scar analysis and the possibility of merging these data with electro-anatomical maps. This is made possible by using a software (ADAS 3D, Galgo Medical, Barcelona, Spain) able to provide 3D heart models by detecting fibrosis along the whole thickness of the myocardial walls. Little is known regarding the applications of this software in the wide spectrum of cardiomyopathies and the potential benefits have yet to be discovered. In this study, we tried to apply the ADAS 3D in the context of CA. Materials and Methods: This study was a retrospectively analysis of consecutive CMR imaging of patients affected by CA that were treated in our center (Marche University Hospital). Wherever possible, the data were processed with the ADAS 3D software and analyzed for a correlation between the morphometric parameters and follow-up events. The outcome was a composite of all-cause mortality, unplanned cardiovascular hospitalizations, sustained ventricular arrhythmias (VAs), permanent reduction in left ventricular ejection fraction, and pacemaker implantation. The secondary outcomes were the need for a pacemaker implantation and sustained VAs. Results: A total of 14 patients were deemed eligible for the software analysis: 8 patients with wild type transthyretin CA, 5 with light chain CA, and 1 with transthyretin hereditary CA. The vast majority of imaging features was not related to the composite outcome, but atrial wall thickening displayed a significant association with both the primary (p = 0.003) and the secondary outcome of pacemaker implantation (p = 0.003). The software was able to differentiate between core zones and border zones of scars, with the latter being the most extensively represented in all patients. Interestingly, in a huge percentage of CMR images, the software identified the highest degree of core zone fibrosis among the epicardial layers and, in those patients, we found a higher incidence of the primary outcome, without reaching statistical significance (p = 0.18). Channels were found in the scar zones in a substantial percentage of patients without a clear correlation with follow-up events. Conclusions: CMR imaging plays a pivotal role in cardiovascular diagnostics. Our analysis shows the feasibility and applicability of such instrument for all types of CA. We could not only differentiate between different layers of scars, but we were also able to identify the presence of fibrosis channels among the different scar zones. None of the data derived from the ADAS 3D software seemed to be related to cardiac events in the follow-up, but this might be imputable to the restricted number of patients enrolled in the study.

Multinational experience with next-generation sequencing: opportunity to identify transthyretin cardiac amyloidosis and Fabry disease.

Sarcomeric hypertrophic cardiomyopathy (HCM) must be differentiated from phenotypically similar conditions because clinical management and prognosis may greatly differ. Patients with unexplained left ventricular hypertrophy require an early, confirmed genetic diagnosis through diagnostic or predictive genetic testing. We tested the feasibility and practicality of the application of a 17-gene next-generation sequencing (NGS) panel to detect the most common genetic causes of HCM and HCM phenocopies, including treatable phenocopies, and report detection rates. Identification of transthyretin cardiac amyloidosis (ATTR-CA) and Fabry disease (FD) is essential because of the availability of disease-specific therapy. Early initiation of these treatments may lead to better clinical outcomes. In this international, multicenter, cross-sectional pilot study, peripheral dried blood spot samples from patients of cardiology clinics with an unexplained increased left ventricular wall thickness (LVWT) of ≥13 mm in one or more left ventricular myocardial segments (measured by imaging methods) were analyzed at a central laboratory. NGS included the detection of known splice regions and flanking regions of 17 genes using the Illumina NextSeq 500 and NovaSeq 6000 sequencing systems. Samples for NGS screening were collected between May 2019 and October 2020 at cardiology clinics in Colombia, Brazil, Mexico, Turkey, Israel, and Saudi Arabia. Out of 535 samples, 128 (23.9%) samples tested positive for pathogenic/likely pathogenic genetic variants associated with HCM or HCM phenocopies with double pathogenic/likely pathogenic variants detected in four samples. Among the 132 (24.7%) detected variants, 115 (21.5%) variants were associated with HCM and 17 (3.2%) variants with HCM phenocopies. Variants in MYH7 (n=60, 11.2%) and MYBPC3 (n=41, 7.7%) were the most common HCM variants. The HCM phenocopy variants included variants in the TTR (n=7, 1.3%) and GLA (n=2, 0.4%) genes. The mean (standard deviation) ages of patients with HCM or HCM phenocopy variants, including TTR and GLA variants, were 42.8 (17.9), 54.6 (17.0), and 69.0 (1.4) years, respectively. The overall diagnostic yield of 24.7% indicates that the screening strategy effectively identified the most common forms of HCM and HCM phenocopies among geographically dispersed patients. The results underscore the importance of including ATTR-CA (TTR variants) and FD (GLA variants), which are treatable disorders, in the differential diagnosis of patients with increased LVWT of unknown etiology.

Incidence and causes of hospitalization in patients with transthyretin (ATTR-CA) and light chain (AL-CA) cardiac amyloidosis

Introduction and objetivesCardiac amyloidosis (CA) is a disorder associated with high number of hospital admissions. Given the scarce information available, we propose an analysis of the incidence and causes of hospitalization in this disease. Material and methodsOne hundred and forty-three patients [128 by transthyretin (ATTR-CA) and 15 by light chains (AL-CA)] included in Registro de Amiloidosis Cardiaca de Galicia (AMIGAL) were evaluated, including all hospitalizations. ResultsDuring a median follow-up of 959 days there were 179 unscheduled hospitalizations [incidence rate (IR) 512.6 admissions per 1000 patients-year], most common due to cardiovascular reasons (n = 109, IR 312.2). Most frequent individual cause of hospitalization was heart failure (n = 87, TI 249.2).AL-CA was associated with a higher IR of unscheduled hospitalizations than ATTR-CA (IR 781 vs. 483.2; HR 1.62; p = 0.029) due to non-cardiovascular admissions (IR 376 vs. 181.2; HR 2.07; p = 0.027). Unscheduled admission-free survival at 1 and 3 years in AL-CA was inferior than in ATTR-CA (46.7% and 20.0% vs. 73.4% and 35.2%, respectively; p = 0.021). ConclusionsCA was associated with high incidence of hospitalizations, being heart failure the most frequent individual cause; unscheduled admission-free survival in AL-CA was lower than in ATTR-CA due mostly to non-cardiovascular admissions.

Use of Bone Scintigraphy in The Diagnosis of Cardiac Amyloidosis

Cardiac amyloidosis is a rare and progressive condition caused by the buildup of amyloid in the heart. There are two common forms of cardiac amyloidosis: light-chain amyloidosis (AL) and transthyretin amyloidosis (ATTR). The deposition of amyloid in the extracellular matrix of the myocardium leads to heart failure over time, and if left untreated, it can even be fatal. For this reason, early diagnosis is essential for both prognosis and improving patients' quality of life. Since cardiac amyloidosis is a potentially treatable condition, early diagnosis is key to improving patient survival and quality of life. There is now compelling evidence showing that nuclear imaging plays a fundamental role in the non-invasive diagnosis of transthyretin cardiac amyloidosis. Due to its high sensitivity and specificity, radiotracer compounds that target the bones are considered sufficient for establishing the diagnosis, avoiding the need for endomyocardial biopsy. In this study, we analyzed data obtained from examinations conducted on patients referred to the Cardiology Department of the "San Giovanni di Dio e Ruggi d'Aragona" University Hospital, who presented with suspected cardiac amyloidosis. These patients underwent scintigraphy with 99mTc-HMDP (hydroxymethylenediphosphonate), using a large-field computerized gamma camera with a parallel-hole collimator and SPECT. After performing early whole-body planar acquisitions at 5 minutes and late acquisitions at 3 hours after intravenous administration of approximately 700 MBq of Tc-99m HMDP, myocardial uptake was observed. Subsequently, targeted acquisitions and SPECT tomographic studies were performed on the myocardial uptake areas. All acquired images were subsequently subjected to quantitative and qualitative analysis, allowing us to extract a large number of parameters reflecting morphological and predictive characteristics using radiomics and more or less automated analysis algorithms. This analysis enabled us to obtain quantitative information that is not apparent in a qualitative image analysis. The ability to extract hidden information from digital medical images is of particular interest as it can enhance the predictive capabilities of existing automatic segmentation algorithms. Extracting new information that was previously hidden can be utilized for automatic image segmentation.

Systemic Vascular Resistance and Myocardial Work Analysis in Hypertrophic Cardiomyopathy and Transthyretin Cardiac Amyloidosis with Preserved Left Ventricular Ejection Fraction.

Background: The pathophysiological impact of systemic vascular resistance (SVR) and pressure-strain loop-derived global myocardial work index (GWI) in hypertrophic cardiomyopathy (HCM) and transthyretin cardiac amyloidosis (ATTR) has been randomly investigated. Methods: Both SVR and GWI were assessed in outpatients consecutively referred at two Italian cardiology departments for heart failure with preserved left ventricular ejection fraction (LVEF), affected by either nonobstructive HCM or wild-type ATTR. Based on relevant cross-tabulations, the patients were gathered into 4 functional classes according to cut-off values of 1440 dyne/s/cm-5 for SVR, and 1576 mm Hg% for GWI, as suggested by previous studies. Results: A total of 60 patients, 30 in each group, aged 61 ± 16 years, with 78% males, were studied. HCM patients were younger than those with ATTR and in a better clinical condition (23% HCM vs. 77% ATTR were NYHA class II-III, p < 0.001). Overall, 51 patients (85%) showed a high SVR, 21/30 HCM (70%), and 30 ATTR (100%) (p < 0.005). Both SVR and GWI (expressions of ventricular-arterial coupling) were impaired in 43% of HCM patients (showing greater LV concentric hypertrophy) and 93% of ATTR patients (in advanced NYHA functional class) (p < 0.001). Conclusions: A substantial percentage of present study population showed impaired SVR and/or GWI, despite preserved LVEF. The proposed classification may shed further light on the pathophysiological and clinical characteristics of such hypertrophic phenotypes.

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

Wild-type transthyretin cardiac amyloidosis (ATTRwt-CA) affects older adults and is currently considered as a rare disorder. We investigated for the first time the prevalence of ATTRwt-CA in elderly individuals from the general population. 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. 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). ATTRwt-CA is uncommon in elderly subjects from the general population, but more frequent than expected for a rare disease.

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.

Temporal Outcomes of Patients Diagnosed With Transthyretin Cardiac Amyloidosis

Transthyretin cardiac amyloidosis (ATTR-CA) is increasingly recognized. Clinical outcomes have evolved over time amidst changes in the diagnostic pathway and advances in therapeutics. To evaluate clinical outcomes over time of ATTR-CA patients with access to disease-modifying therapy. This is a retrospective cohort study of 419 patients diagnosed with ATTR-CA during 2001-2021, comparing clinical characteristics across eras. The primary endpoint was composite all-cause mortality or orthotopic heart transplant (OHT). Time-to-event analysis was performed using Cox proportional hazard modeling controlling for differences amongst cohorts. Patients diagnosed in the more recent years had higher median age (2017-2021: 78 years, 2014-2016: 75 years, 2001-2013: 74 years) and more often had ATTRwt (81.9% vs 82.5% vs. 56.4%) but less severe phenotypes as evidenced by more individuals with Columbia stage I disease (47.6% vs 35.9% vs 22.4%), due to lower biomarkers, more NYHA Class I-II patients (68.9% vs 47.6% vs. 43.6%), and lower use of loop diuretics (67.0% vs 78.6% vs 89.1%). Over time, patients were more frequently treated with Tafamidis (74% vs 37% vs 32%). On multivariable analysis, greater Columbia score (HR 1.42, 95% CI 1.30-1.54, p<0.001) was predictive of death or OHT, while Tafamidis (HR 0.31, 95% CI 0.22-0.44, p<0.001) was associated with greater survival and freedom from OHT. Recently diagnosed ATTR-CA patients have earlier stage disease and substantially lower mortality. Tafamidis is associated with significantly improved survival and freedom from OHT.

Gait abnormalities in older adults with transthyretin cardiac amyloidosis

Background Transthyretin cardiac amyloidosis (ATTR cardiac amyloidosis) is caused by variant (ATTRv) or wild type (ATTRwt) transthyretin. While gait abnormalities have been studied in younger patients with ATTRv amyloidosis, research on gait in older adults with ATTR cardiac amyloidosis is lacking. Given ATTR cardiac amyloidosis’ association with neuropathy and orthopedic manifestations, we explore the gait in this population. Methods Twenty-eight older male ATTR cardiac amyloidosis patients and 11 healthy older male controls walked overground with and without a dual cognitive task. Gait parameters: stride width, length, velocity and stance time percentage were measured using an instrumented mat. ATTR amyloidosis patients were further categorized based on clinical and functional assessments. Results We found significant gait differences between ATTR cardiac amyloidosis patients and healthy controls; patients had more variable, slower, narrower and shorter strides, with their feet spending more time in contact with the ground as opposed to in swing. However, the observed gait differences did not correlate with clinical and functional measures of ATTR cardiac amyloidosis severity. Conclusions Our results suggest that gait analysis could be a complementary tool for characterizing ATTR cardiac amyloidosis patients and may inform clinical care as it relates to falls, management of anticoagulation, and functional independence.

Prevalence of transthyretin cardiac amyloidosis in patients with high-degree AV block

ObjectiveTransthyretin amyloid cardiomyopathy (ATTR-CM) is an infiltrative cardiac disorder caused by deposition of wild type or mutated transthyretin. As ATTR-CM is associated with conduction disease, we sought to determine its...