Transthyretin Cardiac Amyloidosis Research Articles

Cardiac transthyretin amyloidosis in patients with conduction system disease

Abstract Background/Introduction Cardiac amyloidosis (CA) is characterized by extracellular deposition of misfolded proteins in the heart. The data suggest that cardiac amyloidosis is underappreciated as a cause of common cardiac diseases or syndromes. More than 98% of currently diagnosed cardiac amyloidosis result from fibrils consisting of monoclonal immunoglobulin light chains (AL) or transthyretin (ATTR). The natural history of ATTR cardiomyopathy commonly includes both the conduction system disease and arrhythmias, which may occur years before the onset of heart failure. Conduction abnormalities are commonly encountered among patients with CA and constitute an important cause of morbidity and mortality. Most reports agree that pacemakers are most common in wild type ATTR-CA, followed by hereditary ATTR-CA and, finally, AL-CA. Purpose As unexplained LV wall thickness ≥ 12 mm is a screening sign of possible cardiac ATTR, systematicscreening for CA in patients requiring permanent pacemakers with unexplained LV wall thickness of ≥ 12 mm seems to be rational and could possibly lead to early diagnosis of cardiac ATTR. To the best of our knowledge, the usefulness of such screening has not been investigated before. This project, therefore, aims to determine the prevalence of cardiac ATTR and its subtypes in this preselected group, and to propose the most suitable battery of diagnostic procedures for this purpose. Methods Population to be tested: Consecutive patients ≥50 years referred for permanent pacemaker implantation with unexplained LV wall thickness ≥12 mm determined by echocardiography. The research protocol was that of an open-label prospective study. Biochemistry samples including serum troponin I and NT-proBNP were collected before pacemaker implantation. All patients were screened for ATTR-CA according to the recommendations of the Position statement of the ESC Working group on myocardial and pericardial diseases. Tc-DPD scintigraphy scan served as a gold standard for determining the diagnosis of cardiac ATTR. Results Out of 100 consecutive patients meeting inclusion criteria, 15 % suffered from amyloidosis (12 patients were diagnosed with ATTR and 3 with AL cardiac amyloidosis). Table 1 shows a variety of parameters, many of which differed between patient groups with and without amyloidosis, confirming the wide range of parameters significantly associated with cardiac amyloidosis; our ongoing research in this field could lead to the development of a scoring system for detection of cardiac amyloidosis. Conclusions The prevalence of cardiac amyloidosis in the investigated group was 15 %. Systematic screening for ATTR in patients with unexplained LV wall thickness ≥ 12 mm requiring permanent pacemaker implantation seems to be rational and could possibly lead to an earlier diagnosis of cardiac amyloidosis, especially ATTR.

Prognostic staging system correctly identifies high risk groups in cardiac transthyretin amyloidosis treated with tafamidis

Abstract Background The development of different multiparametric staging systems improved the risk assessment of cardiac transthyretin amyloidosis (ATTR-CA) patients substantially. However, to date, all staging systems were validated in treatment-naive ATTR-CA patients. The introduction of tafamidis led to significant changes in the disease trajectory of ATTR-CA, indicating that it may also have an impact on the prognostic accuracy of these staging systems. Purpose Thus, we sought to assess whether the prognostic value of the National Amyloidosis Centre (NAC) staging system, currently considered as the most accurate, is sustained in ATTR-CA patients treated with tafamidis. Methods This retrospective observational study included ATTR-CA patients treated with tafamidis. Patients were continuously followed from treatment initiation to time of death. NT-proBNP and eGFR data collected at baseline were used to stratify patients into low (stage I), intermediate (stage II) and high-risk (stage III) subgroups according to the NAC staging system. Kaplan-Meier analyses were conducted to illustrate overall survival. Differences in overall survival between subgroups were assessed by log rank tests. P-values <0.05 were considered statistically significant. Results A total of 166 ATTR-CA patients (95.2% wild-type) were enrolled. 81 (48.8%), 51 (30.7%) and 34 (20.5%) patients were stratified into stages I, II and III, respectively. Median follow-up was 539 [323-865] days, during which 20 deaths were recorded. Overall survival of the subgroups over time is demonstrated in figure 1. The probability of overall survival was significantly lower for patients in stage III compared to patients in stages I (log rank; p=0.002) and II (log rank; p=0.031). However, no differences in the probability of overall survival were identified between patients in stage I and II (log rank; p=0.679). Conclusions In this cohort of ATTR-CA patients treated with tafamidis, the NAC staging system effectively identified patients at elevated risk of mortality. However, the distinction in survival rates between low- and intermediate-risk groups was less pronounced, suggesting that tafamidis may have a stronger prognostic impact in these groups.Overall Survival across NAC Stages

CMR-derived pulmonary artery to aorta ratio as a predictor of adverse outcome in patients with cardiac transthyretin amyloidosis

Abstract Introduction Cardiac transthyretin amyloidosis (ATTR) represents a heart failure phenotype often accompanied by pulmonary hypertension. The pulmonary artery to aorta ratio (PA/Ao), as assessed on cardiac computed tomography or cardiac magnetic resonance (CMR), has demonstrated to indicate risk for adverse events in a variety of cardiovascular diseases, particularly in heart failure and pulmonary hypertension. However, its prognostic value in cardiac ATTR remains unknown. Aim We aimed to investigate the prognostic value of the PA/Ao ratio in patients with cardiac ATTR. Methods Data of consecutive patients diagnosed with cardiac ATTR undergoing CMR were prospectively collected. PA/Ao ratios were measured from CMRs using axial images (Figure 1A). Adverse outcome, defined as heart failure related hospitalizations and/or mortality, was recorded during follow-up. Results Among the 190 confirmed cardiac ATTR patients (mean age 76±11 years, 79% males), encompassing hereditary transthyretin (vATTR, n=22) and senile (wtATTR, n=168) types, the median pulmonary artery diameter was 28mm (IQR 25-31) and the median ascending aorta diameter was 35mm (IQR 33-39). Over the median follow-up period of 28 months (IQR 11-50 months), 84 (44%) patients experienced an adverse event. Kaplan Meier curves demonstrated an increased risk for adverse outcome in patients with PA/Ao ratios above the median of ≥0.8 (p<0.001 by log rank test, see Figure 1B). In univariate analysis, a high PA/Ao ratio was associated with adverse outcome (HR=10.3, 95% CI=2.59–41.1, p<0.001). When adjusted for age, sex, body mass index and right ventricular function, the PA/Ao ratio remained significantly related to adverse outcome (adj. HR=10.8, 95% CI=1.76–65.8, p=0.010). Conclusion A PA/Ao ratio ≥0.8 on CMR is associated with heart failure hospitalization and death in patients with cardiac ATTR. This threshold, notably lower than the commonly reported ≥1.0 in other patient populations, holds promise for future risk stratification.

Long-term outcomes in patients with dual pathology aortic stenosis and cardiac amyloidosis referred for valve intervention

Abstract Background The coexistence of aortic stenosis (AS) and cardiac amyloidosis (CA) is common. If treated with transcatheter aortic valve implantation (TAVI), patients with the combined phenotype (AS-CA) have a comparable short term survival to those with lone AS, whereas data on longer term outcomes is currently lacking. Purpose This study aimed to evaluate the clinical outcomes of AS-CA compared to lone AS over a 5-year follow-up. Methods Using a prospective, multicentre, observational, case-control design, we screened consecutive patients with severe AS referred for TAVI for co-existing CA. CA screening included blinded 99mTc-DPD bone scintigraphy (Perugini Grade-0 negative, 1-3 increasingly positive) with additional SPECT/CT and light chain assessment prior to intervention. Transthyretin CA (ATTR) was diagnosed by bone scintigraphy and unremarkable light chain assessment, light-chain CA (AL) by endomyocardial biopsy. Mortality (all-cause and cardiovascular [CV]) and hospitalisation for heart failure (HHF) were captured as clinical endpoints. Results 376 patients (83±7 years, 52% female, EuroSCORE-II 4.9±2.9) were recruited, of which 43 (11.4%) had AS-CA (42 ATTR, 1 AL). Compared to lone AS, patients with AS-CA were older with higher cardiac biomarkers (NT-proBNP, high-sensitive Troponin-T) and a higher prevalence of atrial fibrillation. Heart team decision yielded valve replacement in 320 (85%) and conservative management in 56 (15%) patients, without differences between AS-CA and lone AS. Over a median follow-up of 5.4 (Q1: 4.9; Q3: 5.7) years, 230 (61.1%) patients died and 67 (17.8%) experienced HHF (with a total HHF number of 91). AS-CA was associated with higher all-cause mortality (crude HR 1.64, 95%CI 1.15-2.35; log-rank, p=0.006), which remained significant after multivariate adjustment for clinical confounders (EuroSCORE-II, valve replacement; adjusted HR 1.63, 95%CI 1.15-2.32; p=0.006). AS-CA was not associated with CV mortality (log-rank, p=0.18) or time to first HHF (log-rank, p=0.43), but the rate of HHF was significantly higher in AS-CA compared to lone AS (5.7 versus 3.5 per 1,000 patient years, p=0.022). Conclusions Among elderly patients referred for TAVI, long-term outcomes of AS-CA are characterized by higher mortality and a higher rate of heart failure hospitalisations compared to patients with lone AS. Studies evaluating the role of CA-specific treatments are warranted in this population.

Prevalence and prognostic significance of restriction versus systolic dysfunction in patients with transthyretin and light chain cardiac amyloidosis

Abstract The tenet of cardiac amyloidosis (CA) as a paradigm of heart failure with restrictive ventricular physiology and preserved systolic function has come under scrutiny. Thus, we aimed to evaluate the prevalence and clinical significance of left ventricular (LV) systolic dysfunction versus restriction in a large real-world cohort with CA, assessed at the time of diagnosis. Methods This is a multicenter retrospective analysis including 540 transthyretin (ATTR)-CA and 280 light chain (AL)-CA. Patients were divided into 3 phenotypes: 1) preserved LV function: LV ejection fraction (EF) ≥50% associated with grade 0/I diastolic dysfunction; 2) restriction: LV-EF≥50% associated with grade II/III diastolic dysfunction; 3) systolic dysfunction: LV-EF<50% irrespective of diastolic function. We analysed progression from preserved LV function towards the other two phenotypes and their survival. Results In ATTR-CA, prevalence of preserved LV function was 27%, restriction was 44% and systolic dysfunction was 28%. Among patients with preserved LV function, annual conversion rate to restriction was 24% and to systolic dysfunction was 17%. At 3 years, survival free from all-cause mortality was 88%, 76% and 63% respectively (figure A). In AL-CA, prevalence of preserved LV function was 30%, restriction was 49% and systolic dysfunction was 20%. Among patients with preserved LV function, annual conversion rate to restriction was 28% and to systolic dysfunction was 8%. At 3 years, survival free from all-cause mortality was 56%, 39% and 29% respectively (figure B). Conclusions Restriction was the presenting phenotype in less than half of patients, while systolic dysfunction in approximately one quarter. The annual rate of progression form preserved LV function towards restriction or systolic dysfunction was high. In ATTR systolic dysfunction was associated with worse outcome, compared to restriction; in AL both restriction and systolic dysfunction were associated with equally ominous outcome.

Evolution over time of cardiac biomarkers, electrocardiographic and echocardiographic features in a large cohort of patients with wild-type transthyretin cardiac amyloidosis treated with tafamidis

Abstract Introduction Data on evolution of transthyretin wild-type cardiac amyloidosis (ATTRwt) during treatment with tafamidis is scarce. This hinders the quest for parameters of response and a priori treatment eligibility. Purpose To study the evolution of biomarkers, ECG, and echocardiographic features during early tafamidis treatment. Methods We prospectively collected data after 12-18 months of treatment in a single-centre database. Changes of NT-proBNP and high-sensitivity Troponin I (hs-cTnI) between baseline and follow-up evaluations (at 12 and 18 months) were tested for significance. For ECG and echocardiographic features, we considered baseline and the last available follow-up (median interval 11.1 months). Results We included 253 patients (median age 77[71-82]years; 90% males). Median (IQR) baseline NT-proBNP was 2472(1355-4749)ng/L, hs-cTnI 47(30-82)ng/L. Furosemide was administered in 58% of cases (median dose 25[25-50]mg/day). Compared to baseline, NT-proBNP was 2342(1316-4148)ng/L at 12 (p=0.886), and 2633(1393-6063)ng/L at 18 months (p=0.285), with 4% and 30% of patients showing ≥30% and ≥300ng/L increase at 12 and 18 months, respectively; hs-cTnI was 46(29-70)ng/L at 12 (p=0.947), and 44(25-68)ng/L at 18 months (p=0.866), with 35% and 7% showing a ≥20% increase at 12 and 18 months, respectively, and 21 (11.5% over 183 analyzable) with increase at 12 and reduction at 18 months. Patients on furosemide were 69% and 70% at 12 and 18 months, respectively; the dose increased to 37.5(25-75)mg/day at 18 months (p=0.009). At baseline, 117(47%) patients had history/permanent atrial fibrillation (AF). Forty-one(16%) had an implantable electronic device, 16(6%) underwent subsequent implantation. Median PR interval was 210(185-240)msec, trending toward prolongation (p=0.054). QRS duration increased (100[86-130]vs120[90-140]msec, p=0.004), together with conduction disturbances (left anterior fascicular block 30[21%]vs43[29%], p=0.036; right bundle branch block 14[10%]vs27[18%], p=0.002). AF prevalence raised from 19% to 25%. There were no significant changes in left ventricular (LV) geometry (septum thickness 18[16-20]vs18[16-20]mm, p=0.666; end-diastolic diameter 45±7vs45±8mm, p=0.434), systolic function (ejection fraction 51±10%vs49±11%, p=0.070), filling pressures (E/e’ 17[11-20]vs14.9[13-19], p=0.086) and left atrial size (mean volume 46±15vs48±13ml/m2, p=0.649). Tricuspid annular plane systolic excursion (18±4vs17±4mm) and pulmonary artery systolic pressure (40[33-45]vs36[30-45]mmHg) remained stable. Conclusions We did not observe neither improvement nor worsening of laboratory/instrumental variables within the first 12-18 months of tafamidis. There was a progression of electrical disorders. After initial progression hs-cTnI tended to improve. Extended follow-up and a matched case-control series will help identify possible later changes useful to monitor treatment response and effects of supporting heart failure treatments.

Computed tomography-derived myocardial extracellular volume: a diagnostic marker for cardiac amyloidosis in transcatheter aortic valve implantation patients with biopsy confirmation

Abstract Background Transthyretin cardiac amyloidosis (ATTR-CA) appears to be prevalent in aortic stenosis (AS). The coexistence of ATTR-CA and severe AS is associated with an increased risk of hospitalization for heart failure after transcatheter aortic valve implantation (TAVI). The identification of ATTR-CA is of great clinical importance. In this study, we investigated the diagnostic value of computed tomography-derived myocardial extracellular volume (CT-ECV) for the diagnosis of biopsy-proven ATTR-CA. Methods From December 2022 to January 2024, we enrolled patients who underwent both TAVI and myocardial biopsy. CT-ECV was measured as part of routine CT imaging before TAVI and myocardial biopsy for definitive diagnosis of CA. Results Of 131 TAVI patients, 101 patients underwent myocardial biopsy. Eight patients (7.9%) were diagnosed with ATTR-CA. There were no significant differences in electrocardiographic parameters. On echocardiography, left ventricular ejection fraction (64 ± 16% vs. 65 ± 14%, p = 0.84) was similar between the 2 groups, whereas intraventricular septum and left ventricular posterior wall in diastole were thicker in the ATTR-CA group (15 ± 3mm vs. 13 ± 2mm, p = 0.04 and 14 ± 3mm vs. 12 ± 2mm, p <0.01, respectively). Significantly higher CT-ECV values were found in the ATTR-CA group than in the non-ATTR-CA group (32.6 ± 3.7% vs. 28.1 ± 3.7%, p = 0.001). Conclusions Patients with biopsy-proven ATTR-CA had high CT-ECV values. Routine CT-ECV evaluation before TAVI may be useful for the diagnosis of ATTR-CA.

Patient journey from the appearance of red flags to the diagnosis of transthyretin cardiac amyloidosis (ATTR-CM) in Japan: a nationwide retrospective study using a medical claims database

Abstract Introduction Transthyretin amyloid cardiomyopathy (ATTR-CM) is an under-recognized cause of common cardiovascular conditions in the elderly, with relatively high rates among patients diagnosed with heart failure (HF) with preserved ejection fraction. In addition to cardiac symptoms such as HF, extracardiac symptoms such as carpal tunnel syndrome (CTS) and lumbar spinal stenosis (LSS) are also red flags for ATTR-CM. Tafamidis is currently the only disease-modifying therapy approved for the treatment of patients with ATTR-CM and is likely to be more effective in the earlier stage. Patients with ATTR-CM often undergo a long and difficult diagnostic journey because of the nonspecificity of clinical manifestations, resulting in delays in establishing the correct diagnosis. Purpose To identify the timing of appearance of comorbidities in patients with ATTR-CM during diagnosis. Methods In this retrospective, non-interventional, observational study using a claims database (dataset period: April 1, 2014–August 31, 2021), adult patients with a diagnosis of ATTR-CM or prescription for tafamidis 80 mg were included. The index date was defined as the first date of recording ATTR-CM diagnosis or the prescription of tafamidis 80 mg, whichever was earlier. The baseline period was defined as the period between the index date and 6 months before the index date. The onset date was defined as the first date of recording diagnosis of the first red-flags that was suspicious for ATTR-CM. Results Of 11,101,578 patients in the database, 246 patients with ATTR-CM met the inclusion criteria. A total of 239 patients were included, of whom 139 had received tafamidis 80 mg. The median (range) age at the index date was 79.0 (46.0–95.0) years, and 79.9% (191/239) were male. The most frequently reported comorbidity defined as onset of ATTR-CM was conduction disorders (88.7%) followed by atrial fibrillation/atrial flutter (50.6%), hypertensive heart disease (19.7%), aortic stenosis (15.9%), and hypertrophic cardiomyopathy (11.7%), with the median (interquartile range [IQR]) time to the index date being 15.5 (5.0–24.5), 14.0 (5.0–22.0), 9.0 (2.0–18.0), 5.0 (2.0–16.0), and 12.0 (6.5–21.5) months, respectively (Fig. 1). LSS (23.9%), neuropathy (13.0%), and CTS (7.5%) were frequently observed as extracardiac symptoms at baseline, and the median (IQR) time from appearance to the index date was 19 (9.0–28.0), 5.0 (1.0–16.0), and 18.0 (14.0–25.0) months, respectively (Fig. 2). Conclusions This study elucidated the time lag between the appearance of cardiac and extracardiac complications of ATTR-CM and its diagnosis in real-world clinical settings. These novel findings highlight the potential for earlier detection of ATTR-CM.

Tafamidis for the treatment of transthyretin cardiac amyloidosis (ATTR-CM) - Real-world data from a tertiary center

Abstract Introduction Tafamidis 61mg was shown to be the first treatment to reduce cardiovascular hospitalizations and to improve survival in patients with Transthyretin Amyloid Cardiomyopathy (ATTR-CM). Real-world data on the efficacy of transthyretin (TTR) stabilizers in patients with Heart Failure (HF) due to ATTR-CM is scarce. Purpose We aimed to assess the use of tafamidis in our center, that features a dedicated Cardiomyopathy Clinic. Methods We conducted an all-comers single-centre prospective study of consecutive patients with symptomatic HF due to ATTR-CM followed up to November 2023. As per site protocol, the diagnosis was established according to the ESC algorithm and all patients were assessed at least twice yearly. Disease management plans include HF treatment tailored to ATTR-CM (CHAD-STOP) and treatment with disease-modifying tafamidis 61mg. The latter is considered in patients who meet the local protocol criteria, including key inclusion criteria - NYHA class I-II - and none of the exclusion criteria - e.g. estimated glomerular filtration rate (GFR) <25mL/min. The primary endpoint was time to cardiovascular hospitalization or all-cause death. Results A total 226 ATTR-CM patients were identified, of whom 181 had a follow-up of at least 6 months and were included in the analysis (mean age 84 ± 7 years; 81% males, 16% hATTR-CM). Overall, there were 84 patients treated with tafamidis. Compared to non-treated patients, those receiving tafamidis were younger (mean age 83 vs. 86 years, p=0.007), more often with a lower NYHA functional class (e.g., NYHA I-II: 92 vs. 62%; p<0.001), scored higher on performance scales (e.g., Karnovsky >70: 67 vs 33%; p<0.001), and had less comorbidities (e.g., GFR: 40 vs. 30mL/min; p<0.001). Over a median follow-up of 16 months, 68 (37.6%) patients met the primary endpoint (49.5% vs. 22.6%, respectively; p<0.001). In multivariate analysis, treatment with tafamidis was an independent predictor of the primary endpoint (HR 0.24; 95%CI 0.13-0.43; p<0.001), adjusted for NYHA functional class (HR for NYHA I-II vs. III-IV: 0.54; 95%CI 0.32-0.92; p=0.023), NT-proBNP (HR 1.83; 95%CI 1.09-3.08; p=0.023) and high-sensitivity Troponin T (HR per 10 units: 1.01; 95%CI 1.01-1.02; p=0.024). These findings were consistent in multivariate analysis with any combination of the prior variables with either creatinine, GFR, albumin, or TTR type (wild-type vs. mutated). These results were primarily driven due to association of tafamidis treatment with increased survival. Conclusion The use of tafamidis in a cohort of patients with symptomatic HF and ATTR-CM was shown to be independently associated with reduced cardiovascular hospitalization or all-cause death. The effect had a similar magnitude of effect to that of the ATTR-ACT trial, suggesting that our local protocol based on the key criteria from this trial may allow for appropriate patient selection.

Usefulness of scintigraphy with [99mTc]Tc-DPD for the detection of transthyretin cardiac amyloidosis. Reference centre experience in an endemic area

Abstract Background Cardiac amyloidosis (CA) is an infiltrative disorder caused by protein deposition, being transthyretin amyloidosis (ATTR) and primary amyloidosis (AL) the most common forms of CA. ATTR can occur in a hereditary form (ATTRv) or wild-type (ATTRwt). Our area is endemic for ATTRv due to the Val30Met mutation. Purpose To analyse the usefulness of scintigraphy with [99mTc]Tc-DPD (DPD-CS) in an endemic area and its relationship with the diagnostic of CA. Methods We conduct a retrospective study (04/2013-12/2022) of DPD-CS performed for suspected/screening of CA. Our acquisition protocol consists of performing planar images after 3h p.i.(anterior, left anterior oblique and left lateral) +/- SPECT/CT. The assessment of myocardial uptake was evaluated using the Perugini scale (PS: 0-3), considering 2 and 3 as positive scans. DPD-CS results were classified based on the suspicion of CA, according to the 2021 ESC guidelines (we considered cardiomyopathy if: left ventricle hypertrophy ≥12 mm + ≥3 typical signs/symptoms), as well as according to their final diagnosis: ATTRv, asymptomatic carriers, ATTRwt, AL, AA and other non-amyloid (NA) causes. Clinical findings were correlated with the results of the DPD-CS. Results 509 DPD-CS were performed in 478 patients (median age:73 years [22-95], 62% men). Median follow-up: 4.17 years. 127/478 patients were classified with cardiomyopathy (131/509 DPD-CS) and 351/478 without cardiomyopathy (378/509 DPD-CS). 115/509 positive DPD-CS (PS-2: 17, PS-3: 98): 113 had cardiomyopathy (55 ATTRv, 60 ATTRwt) and 2 without cardiomyopathy (1 ATTRv, 1 asymptomatic carrier). These latter two patients developed cardiomyopathy during the follow-up. 394/509 negative DPD-CS (PS 0: 387, PS 1: 7): 18 with cardiomyopathy (1 ATTRv, 1 carrier, 3 AL and 13 NA) and 376 without cardiomyopathy (30 asymptomatic carriers, 88 ATTRv, 2 AA, 9 AL and 247 NA). One patient with cardiomyopathy and ATTRv had initial negative DPD-CS, but became positive DPD-CS on follow-up. All ATTRv without cardiomyopathy presented polyneuropathy. Final diagnoses (according to DPD-CS number): 143 ATTRv (140 Val30Met, 2 Val122Ile, 1 Glu495Gln), 32 carriers (29 Val30Met, 2 Val122Ile, 1 His51Asn), 61 ATTRwt,12 AL, 2 AA and 259 NA. The analysis obtained after correlating the results of the DPD-CS regarding the presence of cardiomyopathy was: sensitivity 86.25%, specificity 99.47%, PPV 98.26% and NPV 95.43%. Conclusion Our study reaffirms the usefulness of DPD-CS in the non-invasive diagnosis of transthyretin CA. DPD-CS has an additional value in endemic areas for the early detection of CA in asymptomatic patients.

Evaluation of the 2021 ESC recommendations for family screening in hereditary transthyretin cardiac amyloidosis

Abstract Background The 2021 European Society of Cardiology (ESC) screening recommendations for individuals carrying a pathogenic transthyretin amyloidosis (ATTR) variant (ATTRv) are based on expert opinion. We aimed to (1) determine the yield of ATTR cardiomyopathy (ATTR-CM) at baseline; (2) evaluate the performance of the 2021 ESC position statement on initiating screening for ATTRv carriers; (3) establish the value of first-line tests recommended in ATTRv carriers; and (4) examine the yield of serial evaluation. Methods We included 159 relatives (median age 55.6 [interquartile range 43.2-65.9] years, 52% male) at-risk for developing ATTR-CM from 10 centres. ATTR-CM diagnosis was defined as the presence of either 1) cardiac tracer uptake in bone scintigraphy as recommended; or 2) cardiac biopsy proven positive for ATTR. Our secondary endpoint was a composite of heart failure symptoms (NYHA class³II) and conduction disorders necessitating pacemaker implantation. An individual fulfilled screening criteria as proposed by the 2021 ESC position statement if: 1) cardiac screening was performed ~10 years prior to disease onset in the proband (or in other individuals with the same variant if disease onset in the family was unknown); or 2) had extracardiac amyloidosis as diagnosed by a Neurologist or Ophthalmologist. Results At baseline, 40/159 (25%) relatives were diagnosed with ATTR-CM. Of those 40 relatives, 20 (50%) met the secondary endpoint. Relatives diagnosed with ATTR-CM were significantly older (66.5 [61.0-75.2] vs. 49.2 [40.8-58.8] years, p<0.001)(Figure 1A). Figure 1B-C visualizes the yield of screening by screening indications of the 2021 ESC position statement. Both screening for age, extra-cardiac amyloidosis or both age and extra-cardiac amyloidosis as indication to screen had a 31% (n=17/54), 18% (n=2/11) and 68% (n=19/28) yield of ATTR-CM, respectively. Diagnosis of ATTR-CM in relatives without an indication to screen was rare (3%; n=2/66). As a result, indication to screen as proposed by the 2021 ESC position statement yielded an almost excellent negative predictive value (97%). Other independent pre-screening predictors were infrequently identified variants and male sex. Of note, 13% of relatives with ATTR-CM did not show any "red flags" of cardiac amyloidosis on electrocardiogram (ECG), echocardiogram, and laboratory parameters. Excluding those who meet the secondary endpoint (i.e. those who already should have been diagnosed based on symptoms), ATTR-CM diagnosis in the absence of "red flags" increased from 13% to 26%. The yield of repeat bone scintigraphy (n=41 ATTRv carriers; follow-up 3.1 [2.2-5.2] years) at 3-years’ interval was 9.4% (Figure 2). Conclusion The recommendations made by the 2021 ESC position statement are adequate. Clinicians should adhere to the 3-year repeat bone scintigraphy as progressing to ATTR-CM in the absence of "red flags" and symptoms is not uncommon.Cardiac amyloidosis at baselineATTR-CM development during follow-up

Clinical and genetic profiles of patients with hereditary and wild type transthyretin amyloidosis: the transthyretin cardiac amyloidosis registry in the state of Sao Paulo, Brazil REACT-SP

Abstract Introduction Transthyretin amyloidosis (ATTR) is a multisystem disease caused by the deposition of fibrillar protein in organs and tissues. ATTR genotypes and phenotypes are highly heterogeneous. Purpose We designed the Transthyretin Cardiac Amyloidosis Registry in the state of São Paulo (REACT-SP), aiming to describe the demographic, genetic, clinical, and diagnostic test results and treatment of patients with ATTR. Methods We present data on physical signs and symptoms, cardiac and neurological assessments, and genetics in patients enrolled in the Transthyretin Cardiac Amyloidosis Registry in the state of São Paulo, Brazil. Results Six hundred-forty-four patients were enrolled, 505 with the variant form (ATTRv) and 139 with wild-type (ATTRwt). Sixteen different mutations were detected, the most common being Val50Met (48.3%) and V142Ile (40.8%). Overall, more than half of the patients presented cardiological involvement, and the difference in this proportion between the ATTRv and ATTRwt groups was significant (43.9 vs. 89.9%; p<0.001). The neurological phenotype also differed between ATTRv and ATTRwt (56.8 vs. 31.7%; p<0.001). The mixed phenotype was found in 25.6% of the population, without a significant difference between the forms of amyloidosis. A group of patients remained asymptomatic (10.4%), with a lower proportion of asymptomatic ATTRwt patients. The median time between the onset of symptoms and diagnosis was 1,853 (IQR 1277–2997) days, which was longer in ATTRv patients than in ATTRwt patients (p<0.001). Sinus rhythm was reported in 74.2%, atrial fibrillation in 17.0%, low voltage in 28.6%, repolarization abnormalities in 39.8%, and pseudo infarction in 27.4%. Echocardiography showed median Left Ventricular Ejection Fraction (LVEF) was 60%, Interventricular Septum (IVS) 14 mm, Posterior Wall Thickness (PWT) 13 mm, Left Atrium (LA) 41 mm, Left Ventricular Diastolic Diameter (LVDD) 45 mm, Left Ventricular Systolic Diameter (LVSD) 30 mm, basal Right Ventricular Diastolic Diameter (RVDD) 35 mm and Left Ventricle (LV) longitudinal strain 9.1%. There was some degree of LV diastolic dysfunction in 38.4%, apical sparing in 31.3%, and thrombus or masses in 1.0%. Late Gadolinium Enhancement (LGE) was absent in 29% and was subendocardial in 35.5%, transmural in 13.7%, mesocardial in 13.7%, and epicardial in 8.2%. Conclusions This study details the clinical and genetic spectrum of patients with ATTR in São Paulo, Brazil. This preliminary analysis highlights the considerable phenotypic heterogeneity of neurological and cardiac manifestations in patients with variant and wild-type ATTR.

Natural course and effect of tafamidis treatment in real-life octogenarians with wild-type transthyretin cardiac amyloidosis: an international multi-centre analysis

Abstract Background and aims In real-life, wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM) is increasingly diagnosed in elderly patients above 80 years old. Nevertheless, specific data on natural course and outcome under tafamidis treatment in octogenarians are particularly scarce. We aimed to study tafamidis impact on mortality and its determinants in real-life ATTRwt-CM octogenarians. Methods International multi-centric cohort study of 710 consecutive ATTRwt-CM patients, stratified between octogenarians and non-octogenarians at diagnose and tafamidis naive or treatment. Mean follow-up was 2.2±1.8 years to all-cause mortality endpoint. Results The cohort consisted of 58.3% octogenarians (median 84 years, 74.2% male). Before tafamidis availability, natural course in octogenarians (148/257) versus non-octogenarians (109/257) was poor with 41% three-year and 70% five-year mortality versus 19% and 42%, respectively (p<0.001). Since tafamidis availability, 70.1% (253/361) octogenarians were initiated on tafamidis, less than 83.7% (231/276) non-octogenarians (p<0.001). Tafamidis discontinuation was similar (octogenarians 11.4%, non-octogenarians 7.9%, p=0.260). Overall tafamidis treated octogenarians had better survival than untreated octogenarians (p<0.001) and untreated non-octogenarians (p=0.026), with 23% three-year and 51% five-year mortality. Tafamidis treatment related to lower mortality in octogenarians (HR 0.37, 95%CI 0.20-0.67, p=0.001), after correcting for age, NAC stage and NYHA class, the other independent predictors. Propensity-score matching for those variables in 218 subjects confirmed tafamidis mortality benefit in octogenarians (p<0.001). Octogenarians had poorer survival under tafamidis, when initiated at ≥90 years old (p<0.001), NAC stage ≥3 (p=0.001) or NYHA class ≥3 (p=0.055). Conclusions Tafamidis treatment in real-life octogenarians independently improves survival, with better effect of early initiation at lower disease stage and age.Structured graphical abstractDistributions within age category

In-depth morphological and functional analysis of ATTR-CA myocardial cells and niche by electron microscopic 3D reconstruction

Abstract Background Cell-cell interactions and interplay with extracellular matrix are known to be important in the steady state and pathological conditions, including wild-type transthyretin cardiac amyloidosis (wtATTR-CA). However, alterations of the microstructure of cardiomyocytes (CMs) and cardiac niches have not been well analyzed. Normal histological staining is usually limited in resolution, and 2D electron microscopy cannot capture stereoscopic images or the distribution of target particles and organelles in intra- and extracellular 3D space, so novel methods are being attempted. Methods and Results Using Serial Block Face-Scanning Electron Microscopy (SBF-SEM) and a 3D structural reconstruction system, we for the first time investigated the microstructure of human myocardial tissue from control hypertrophied heart (hypertensive heart disease) and wtATTR-CA patients. The microstructure of myocardial niche, cell morphology/numbers, and the distribution of intracellular organelles such as intercalated discs (ICDs) were compared to control endomyocardial biopsy (EMB) samples (2 controls vs 5 wtATTR-CA patients). In all wtATTR-CA samples, amyloid fibers were deposited originating around the capillary structures with various electron densities, compressing myocardial cells not only from the periphery but also dividing them from the center of the cell body, and CMs showed degeneration and dwarfing according to the severity of amyloid fiber deposition (Figure 1). The capillary structures showed degeneration and narrowing with stratified basement membrane, and rarefaction (3378±216.5 vs 1448±116.8/mm2, p<0.0001). Notably, the stromal cells (pericytes, fibroblasts, macrophages) were more likely buried by amyloid fibers than CMs, and their numbers were also reduced, indicating a loss of adjacent and intercellular interaction with capillaries and CMs (Fig. 2, 1892±194.4 vs 1189±107.4 mm2, p=0.0043). This method can also be used to analyze intracellular organelles and microstructures in CMs. In ATTR-CA, morphological abnormalities were observed in ICDs (Figure 3) and mitochondria. Conclusion In the ATTR-CM patients, there was a significant decrease in the number of capillaries in accordance with the deposition of myocardial amyloid fibers, as well as a decrease in stromal cells. These results support the hypothesis that amyloid fibril deposition not only causes chronic myocardial ischemia, but also reduces the number of niche cells, which play a supportive role for CM function and entirely exacerbate the damage. The SBF-SEM is an innovative tool for 3D imaging and quantitative analysis of myocardial ultrastructure and functions.Methods & Figure 1Figure 2 and Figure 3

Prevalence of amyloidosis among patients with mild to severe aortic stenosis. Validation of screening parameters

Abstract Background Cardiac amyloidosis (CA) is an increasingly recognized cause of human heart failure. Up to 16% of patients with severe aortic stenosis (AS) undergoing transcatheter valve replacement have been reported to suffer concomitant transthyretin CA (ATTR). Since the diagnosis of CA implies distinct therapies with prognostic relevance, early diagnosis of CA is crucial. Different parameters have been described to improve screening accuracy for detection of CA, but it is unknown whether these parameters are valid, and the prevalence of CA is stable throughout the spectrum of AS. Purpose To validate screening parameters for the detection of CA in mild, moderate and severe AS. Methods Patient 65 years and above undergoing echocardiography with mild to severe AS, defined as calculated valve orifice area <2 cm2 by velocity-time-integral, and an intraventricular septum thickness > 11mm, fulfilling at least one of two additional criteria (Sokolow-Lyon-Index to left ventricular mass index ratio < 1.5 or stroke volume index < 35 ml/m2) were prospectively included and screened for CA using bone scintigraphy and immunofixation in blood and urine. Results 57 patients were included and completed the diagnostic work-up. Mean age was 83 ± 0.7 years and 71% were male. Overall, 15 (26%) of patients were diagnosed with CA (12 with ATTR and 3 with light-chain CA, Figure1A). 17 patients had mild, 21 had moderate and 19 patients were diagnosed with severe AS. Among patients with mild AS 41% were diagnosed with CA, whereas only 24% of patients with moderate and 16% of patients with severe AS suffered CA (Figure 1B), these results did not show statistically significant differences (p= 0.2, by Chi-Square Quadrat test). Patients with CA were less likely to have NYHA classes I or II (20 vs. 57%, p= 0.03), had higher values of NT-proBNP (4572 [2323; 6044] vs. 817 [589; 2571], p< 0.001) and high-sensitive troponin (66 [47; 103.5] vs. 22.5 [17; 33.6], p< 0.001) and were more likely to have an atrioventricular block of any degree (60 vs. 26%, p=0.04). Conclusion Prevalence of CA among patients fulfilling the criteria of this screening algorithm seems to be high independent of AS severity. Clinicians should not only focus on patients with severe AS to detect CA early. Further research is needed to estimate the prevalence of CA among all patients with AS. Figure 1 A: Among patients with an age >65 years, IVS >11mm, AS and SLI/LVMMI >1.5 or SVI <35 ml/m2 26% (red area) of patients were diagnosed with CA (n= 57). B: In patients with mild AS 41% were diagnosed with CA, whereas in patients with moderate AS only 24% and in patients with severe AS 16% had CA. These differences did not show statistical significance (p= 0.2). IVS: intraventricular septum, AS: aortic stenosis, SLI: Skolow-Lyon-Index, LVMM= left ventricular myocardial mass index, SVI: stroke volume index, CA: cardiac-amyloidosis. (Statistics performed by chi-square test using GraphPad Prism 9.0).

Incidence and clinical characteristics of cardiac amyloidosis in Tuscany and Umbria

Abstract Background Recent advances in imaging and increased disease awareness have led to a significant rise in newly diagnosed cases of cardiac amyloidosis (CA) over the past decade. However, there remains a lack of epidemiological data regarding the true incidence of the disease. Purpose To determine the incidence and clinical characteristics of newly diagnosed cases of CA in a large Italian population. Methods Subjects with suspected CA underwent diagnostic work-up in 20 Centers in Tuscany and Umbria regions within the Cardiac Amyloidosis RegistRY (CARRY), between January 1st 2022 and December 31st 2022. Results A total of 551 subjects were enrolled in the registry, with complete data on the final diagnosis available for 448 individuals. CA was diagnosed in 179 patients (40%), with 28 (16%) classified as light chain CA (AL-CA), 114 (64%) wild-type transthyretin CA (ATTR-CA), 12 (7%) variant ATTR-CA, and 25 (13%) undetermined CA. Considering a reference population in Tuscany and Umbria in 2022 (4,518,388, according to the Italian National Institute of Statistics), this yields an estimated cumulative incidence of 39.6 cases per million inhabitants per year. Alternative diagnoses in the remaining patients mostly included hypertensive heart disease (n=157, 58%), hypertrophic cardiomyopathy (n=25, 9%), moderate-to-severe valvular heart disease (n=11, 4%), or a mixed phenotype (n=72, 27%). The primary referral pathway for the suspicion of CA was cardiological (n=345, 77%), followed by incidental finding during screening visits (n=58, 13%), and haematology referral (n=33, 7%). Patients with confirmed CA were older (81 [75-85] vs. 77 [72-83] years, p<0.001), and more frequently reported musculoskeletal red flags of CA, such as carpal tunnel syndrome (85 [48%] vs. 53 [20%] years, p<0.001), and spontaneous tendon rupture (39 [22%] vs. 18 [7%] years, p<0.001). Median time to diagnosis from clinical suspicion was 73 (37-140) days for CA and 84 (36-156) days for alternative diagnoses (p=0.564). Conclusions The diagnosis of CA is on the rise globally, with an estimated incidence of 39.6 new cases per million inhabitants per year in two large regions of Italy. These findings should inform policymakers in redefining the status of CA as a rare disease, potentially influencing patient care and treatment costs.

Artificial intelligence (AI)-enhanced electrocardiography: a machine-learning model for differential diagnosis between hypertrophic cardiomyopathy, cardiac amyloidosis and Anderson-Fabry disease

Abstract Background The differential diagnosis between Hypertrophic Cardiomyopathy (HCM) and phenocopies is challenging and relies on a comprehensive approach, which includes clinical and instrumental data, as well as laboratory exams and genetic testing. In this setting, 12-lead electrocardiogram (ECG) represents a valuable tool, but although typical patterns have been described, their diagnostic ability to discriminate between different etiologies is limited and requires considerable clinical experience. However, a correct diagnosis is of pivotal importance, allowing the prompt initiation of phenotype-specific therapies and consequently improving patient survival. Purpose Aim of this study was to develop a machine-learning model based on human-based ECG features to support the differential diagnosis between HCM, Cardiac Amyloidosis (CA) and Anderson-Fabry Disease (AFD). Methods We retrospectively examined ECGs of 200 patients, 50 affected by HCM, 100 affected by CA (50 AL CA and 50 transthyretin CA) and 50 with a diagnosis of AFD cardiomyopathy. The patients were then divided in sinus rhythm (SR) subgroup (158 patients) and atrial fibrillation (AF) subgroup (42 patients). For each subgroup, patients were randomly split into a training (80%) and a testing cohort (20%), and a random forest (RF) model was trained on the training cohort, with hyperparameter tuning via 10-fold cross validation. The resulting model was then tested on the testing cohort to assess its predictive accuracy. Results Both RF models (SR and AF) showed good discriminative performance in this multiclass classification task on the testing cohort [SR: accuracy 67%; multiclass area under the curve (AUC) 0.797, 95% confidence interval (CI) 0.472 -0.827; AF: accuracy 75%; multiclass AUC 0.792, 95% CI 0.349 – 0.968]. Figure 1 and figure 2 report for each model the rank of the most important variables for class prediction. Conclusions An AI-based ECG interpretation based on human-derived ECG features can predict the etiology underlying an hypertrophic phenotype, helping to perform a correct diagnosis and consequently to set a specific therapeutic process.

Echocardiographic Phenotype in Severe Aortic Stenosis With and Without Transthyretin Cardiac Amyloidosis: The AMY-TAVI Study.

The relative apical sparing pattern of left ventricular (LV) longitudinal strain (RELAPS]>1) has been described as a typical sign of cardiac amyloidosis (CA). The objective was to validate this pattern in concomitant CA and aortic stenosis (AS) and to identify new echocardiographic variables suggestive of CA in the presence of AS. 324 consecutive patients (age 81.5±5.8 years, 51% women) with AS who underwent transcatheter aortic valve implantation (TAVI) were prospectively included. 2D-Speckle-tracking echocardiography was performed. Following TAVI, 99mTc-DPD-scintigraphy and protein electrophoresis were performed to screen for CA. 38 patients (11.7%) showed cardiac uptake in scintigraphy: 14 patients (4.3%) with grade 1, 13 (4%) with grade 2, and 11 (3.4%) with grade 3. Patients with grades 2 and 3 (AS-CA group) had more LV hypertrophy (LV mass index: 188 vs.172 g/m2, p=0.032), lower transvalvular aortic pressure gradient (p<0.003), and higher prevalence of low-gradient AS (50% vs.19%, p=0.001), as well as greater diastolic and systolic dysfunction. Strain analysis was limited to 243 patients due to poor acoustic window and COVID-19 restrictions (81 lost: 79 in AS alone, 1 each in AS-DPD1 and AS-CA groups). RELAPS>1 was more prevalent in AS-CA group (74% vs.44%, p=0.006). An echocardiographic prediction model (GRAM score) for CA in the presence of AS, that is more sensitive and specific than RELAPS>1 alone, is proposed using the LV mass, maximum aortic gradient, and RELAPS>1, in addition to age (AUC:0.85, 95%CI: 0.77-0.93). RELAPS>1 is more prevalent in AS-CA but can occur in almost half of AS patients without CA, which reduces its value as a screening tool. A more sensitive and specific prediction score for CA in patients with severe AS is proposed.

Microvascular obstruction in cardiac amyloidosis.

Cardiac amyloidosis (CA) is characterized by deposition of amyloid fibrils within the extracellular space, causing disarray of the myocardial structure and capillary architecture. This study aims to characterize the prevalence of microvascular obstruction (MVO) in patients with CA and to assess the association between MVO and prognosis. The study population comprised 800 patients, of which 400 had light-chain CA (AL-CA) and 400 had transthyretin CA (ATTR-CA). MVO was present in 221 (27.6%) patients, and more common in ATTR-CA than AL-CA (124 [56.1%] vs. 97 [43.9%], p = 0.033). Patients with MVO had a more severe cardiac phenotype evidenced by higher N-terminal pro-brain natriuretic peptide (3516 ng/L [1944-6247] vs. 2508 ng/L [1203-5752], p < 0.001), worse global longitudinal strain (-10.5% [-12.6; -7.9] vs. -12.0% [-16.0; -8.9], p < 0.001), and higher extracellular volume (56% [51-61] vs. 50% [45-57], p < 0.001). Patients with AL-CA and MVO had a higher serum troponin (86 ng/L [47-148] vs. 59 ng/L [44-78], p < 0.001), and higher T2 (53 ms [50-56] vs. 50 ms [48-52], p < 0.001), but lower extracellular volume (55% [50-60] vs. 58% [53-61], p = 0.008) and lower indexed myocyte cell volume (48.6 g/m2 [41.1-59.8] vs. 55.7 g/m2 [47.5-68.4], p < 0.001) than patients with ATTR-CA and MVO. MVO was associated with an increased risk of mortality in the overall population (hazard ratio [HR] 1.28, 95% confidence interval [CI] 1.03-1.59, p = 0.025), and the subgroup with AL-CA (HR 1.59, 95% CI 1.17-2.17, p = 0.003) but not ATTR-CA (HR 1.04, 95% CI 0.77-1.40, p = 0.814). Microvascular obstruction is common in CA and is related to markers of amyloid infiltration. MVO is associated with an increased risk of mortality in AL-CA, but not in ATTR-CA. This reflects the intrinsic differences in disease biology between these two forms of CA, with MVO likely related to multiple myocardial processes, amyloid infiltration, oedema and myocyte death.

Transthyretin Cardiac Amyloidosis: Insights into Wild-Type Variants and Familial Amyloid Cardiomyopathy

Transthyretin (TTR) cardiac amyloidosis is a progressive condition characterized by amyloid fibril deposition in the heart, leading to heart failure. This review focuses on insights into wild-type (ATTRwt) and familial (ATTRm) variants of TTR amyloidosis. The pathophysiology involves TTR tetramer destabilization, monomer misfolding, and amyloid fibril formation. Therapeutic advances, including TTR stabilizers like tafamidis and Diflunisal, and gene-silencing agents such as patisiran and inotersen, show promise in managing the disease. Despite these advancements, early diagnosis remains challenging, and side effects of current therapies necessitate the development of safer, more effective treatments. Future research should focus on novel therapies, improved diagnostic methods, and personalized treatment strategies to enhance patient outcomes. This review underscores the importance of continued innovation and collaboration in tackling TTR cardiac amyloidosis.