Effect of tafamidis on left atrial function of patients with transthyretin amyloid cardiomyopathy

Transthyretin amyloid cardiomyopathy (ATTR-CM) is characterized by the functional and structural effects of amyloid infiltration, predominantly within the ventricles, causing biventricular wall thickening. Amyloid infiltration can be observed in the left atrium in ATTR-CM patients, but the association of left atrial (LA) myocardial function with cardiovascular events and of changes in LA myocardial function with tafamidis administration have not yet been clarified. Our aim was, therefore, to use speckle-tracking strain for investigating LA myocardial function in patients with ATTR-CM treated with tafamidis. We studied 55 patients with biopsy-proven ATTR-CM who had been treated with tafamidis (age: 76 ± 2 years, male: 93%). For speckle-tracking analysis of LA myocardial function, the systolic LA strain (LA reservoir function) was defined for this study as LA myocardial function from the apical 4-chamber view. The primary endpoint was defined as a composite comprising cardiovascular death and/or heart failure hospitalization after tafamidis administration over a median follow-up period of 28 ± 4 months. Patients with baseline LA strain < 8.6% (median value) experienced significantly more cardiovascular events than those without (log-rank P = 0.002). Moreover, LA strain in 26 patients worsened after tafamidis administration, and multivariate logistic regression analysis showed age, global longitudinal strain and relative apical longitudinal strain index were identified as independent determinants of deterioration of LA strain after tafamidis administration. In conclusion, baseline LA reservoir function is closely associated with cardiovascular events after tafamidis administration, and could be an additional parameter for the management of patients with ATTR-CM.

Prevalence of transthyretin amyloid cardiomyopathy in pacemaker patients

AIMS

Transthyretin amyloid cardiomyopathy (ATTR-CM) is characterized by increased wall thickness, diastolic dysfunction and progressive heart failure symptoms. The disease may infiltrate the conduction system leading to conduction disturbances requiring an implantation of permanent cardiac pacemaker (PM), but the extent is unknown. Here, we report the prevalence of ATTR-CM in patients ≥65 years with PM.

METHODS AND RESULTS

In this prospective, cross-sectional single-centre study patients were recruited from our out-patient pacemaker clinic. Eligibility criteria were age above 65 years, permanent cardiac pacemaker and competent to give informed consent. Patients underwent echocardiography at the pacemaker visit and were referred to 99mTc-DPD-scintigraphy (DPD) and blood samples if septum thickness was ≥12 mm, defined as left ventricular hypertrophy (LVH). Fifty eight of the 128 patients had LVH on echocardiography. Eleven patients had a DPD-scintigraphy based diagnosis of ATTR-CM, which represent 19% of patients with LVH and 9% of the total cohort. Patients diagnosed with ATTR-CM had higher concentrations of cardiac biomarkers (P < 0.001), higher E/E' (P = 0.001), and lower global longitudinal strain (P = 0.003) on echocardiography and more heart failure symptoms (P = 0.001).

CONCLUSIONS

The prevalence of ATTR-CM in elderly patients with PM and LVH on echocardiography was 19%.

Efficacy of Computed Tomography-Based Evaluation of Myocardial Extracellular Volume Combined With Red Flags for Early Screening of Concealed Cardiac Amyloidosis in Patients With Atrial Fibrillation

BACKGROUND

The prevalence of transthyretin amyloid cardiomyopathy (ATTR-CM) in atrial fibrillation (AF) patients remains unclear. We explored the efficacy of computed tomography-based myocardial extracellular volume (CT-ECV) combined with red flags for the early screening of concealed ATTR-CM in AF patients undergoing catheter ablation.Methods and Results: Patients referred for AF ablation at Oita University Hospital were prescreened using the red-flag signs defined by echocardiographic or electrocardiographic findings, medical history, symptoms, and blood biochemical findings. Myocardial CT-ECV was quantified in red flag-positive patients using routine pre-AF ablation planning cardiac CT with the addition of delayed-phase cardiac CT scans. Patients with high (>35%) ECV were evaluated using technetium pyrophosphate (99 mTc-PYP) scintigraphy. A cardiac biopsy was performed during the planned AF ablation procedure if 99 mTc-PYP scintigraphy was positive. Between June 2022 and June 2023, 342 patients were referred for AF ablation. Sixty-seven (19.6%) patients had at least one of the red-flag signs. Myocardial CT-ECV was evaluated in 57 patients because of contraindications to contrast media, revealing that 16 patients had high CT-ECV. Of these, 6 patients showed a positive 99 mTc-PYP study, and 6 patients were subsequently diagnosed with wild-type ATTR-CM via cardiac biopsy and genetic testing.

CONCLUSIONS

CT-ECV combined with red flags could contribute to the systematic early screening of concealed ATTR-CM in AF patients undergoing catheter ablation.

Effect of long-term tafamidis treatment on health-related quality of life in patients with transthyretin amyloid cardiomyopathy

AIMS

To evaluate the effect of long-term tafamidis treatment on health-related quality of life (HRQoL) in patients with transthyretin amyloid cardiomyopathy (ATTR-CM) enrolled in the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT) and long-term extension (LTE) study.

METHODS AND RESULTS

We examined change from baseline in Kansas City Cardiomyopathy Questionnaire overall summary (KCCQ-OS) and clinical summary (KCCQ-CS) scores in patients who received tafamidis meglumine 80 mg for 30 months in ATTR-ACT and tafamidis (meglumine 80 mg or bioequivalent free acid 61 mg) for 30 months in the LTE study, and in patients who received placebo for 30 months in ATTR-ACT and tafamidis for 30 months in the LTE study. In ATTR-ACT, 176 and 177 patients were randomized to tafamidis 80 mg and placebo, respectively. Patients who continuously received tafamidis had a 6- to 7-point reduction in least squares (LS) mean (standard error) KCCQ-OS and KCCQ-CS scores at month 30 (-6.25 [1.53] and -7.48 [1.39]), with little or no further decline over the next 30 months (-5.92 [1.77] and -9.21 [1.88] at month 60). Patients who received placebo in ATTR-ACT had a 20-point reduction in LS mean KCCQ-OS and KCCQ-CS scores at month 30 (-19.60 [1.94] and -19.90 [2.01]), but the decline slowed after initiating tafamidis (-24.70 [3.04] and -25.30 [3.36] at month 60).

CONCLUSION

Tafamidis reduced HRQoL decline in patients with ATTR-CM. Patients continuously treated with tafamidis for 60 months demonstrated stabilized HRQoL. In patients who initially received placebo in ATTR-ACT, tafamidis reduced the decline in HRQoL during the LTE study.

Cost-effectiveness of systematic screening and treatment of transthyretin amyloid cardiomyopathy (ATTR-CM) in patients with heart failure with preserved ejection fraction (HFpEF) in United States

BACKGROUND

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underdiagnosed cause of heart failure in clinical practice. 99mTc-pyrophosphate scintigraphy (PYP-scan) improves the accuracy of ATTR-CM detection, enabling timely initiation of tafamidis, a drug that slows the progression of ATTR-CM and lowers the risk of adverse cardiac events. PYP-scans, serum free light-chain (FLC) test and immunofixation electrophoresis (IFE) are critical components of a systematic screening. We assessed the cost-effectiveness of universal systematic screening (USS) compared to standard-of-care (SoC) selected clinical referrals for the systematic screening in patients aged 60 years or older with heart failure with preserved ejection fraction (HFpEF) and ventricular wall thickness of at least 12 mm.

METHODS

Two screening strategies, USS versus SoC screening for ATTR-CM were compared in a model-based assessment. Treatment decisions were based upon the accuracy of each screening strategy, which was followed by Markov state transitions across New York Heart Association (NYHA) functional classes and death. Model inputs were identified from a literature review. We calculated lifetime cost in 2022 US dollars and quality adjusted life-years (QALYs) of each strategy. The primary outcome was the incremental cost-effectiveness ratio (ICER).

RESULTS

The USS was associated with a significant increase in lifetime costs ($124,380 vs. $70,412) and modest improvement in QALYs (4.42 QALYs vs 4.36 QALYs). The ICER for the USS was $919,509 per QALY gained. ICER was sensitive to the age at the time of ATTR-CM diagnosis, true prevalence rate of ATTR-CM, and daily cost of tafamidis.

CONCLUSIONS

Owing to the high cost of treatment with tafamidis, USS along with PYP scan for ATTR-CM in older HFpEF patients with ventricular wall thickening is unlikely to become a cost-effective strategy at a liberal WTP threshold.

Biochemical and biophysical properties of a rare TTRA81V mutation causing mild transthyretin amyloid cardiomyopathy

AIMS

We conducted a presentation on an 84-year-old male patient who has been diagnosed with TTRA81V (p. TTRA101V) hereditary transthyretin cardiac amyloidosis (hATTR-CM). In order to establish its pathogenicity, we extensively investigated the biochemical and biophysical properties of the condition.

METHODS AND RESULTS

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an increasingly acknowledged progressive infiltrative cardiomyopathy that leads to heart failure and potentially fatal arrhythmias. Gaining a comprehensive understanding of the biochemical and biophysical characteristics of genetically mutated TTR proteins serves as the fundamental cornerstone for delivering precise medical care to individuals affected by ATTR. Laboratory assessments indicated a brain natriuretic peptide of 200.12 ng/L (normal range: 0-100 ng/L) and high-sensitivity cardiac troponin I of 0.189 μg/L (normal range: 0-0.1 μg/L). Echocardiography identified left atrial enlargement, symmetrical left ventricular hypertrophy (16 mm septal and 16 mm posterior wall), and a left ventricular ejection fraction of 56%. Cardiac-enhanced magnetic resonance imaging revealed subendocardial late gadolinium enhancement. Tc-99m-PYP nuclear scintigraphy confirmed grade 3 myocardial uptake, showing an increased heart-to-contralateral ratio (H/CL = 2.33). Genetic testing revealed a heterozygous missense mutation in the TTR gene (c.302C>T), resulting in an alanine-to-valine residue change (p. Ala81Val, following the first 20 residues of signal sequence nomenclature). Biochemical analysis of this variant displayed compromised kinetic stability in both the TTRA81V:WT (wild-type) heterozygote protein (half-life, t1/2  = 21 h) and the TTRA81V homozygote protein (t1/2  = 17.5 h). The kinetic stability fell between that of the TTRWT (t1/2  = 42 h) and the early-onset TTRL55P mutation (t1/2  = 4.4 h), indicating the patient's late-onset condition. Kinetic stabilizers (Tafamidis, Diflunisal, and AG10) all exhibited the capacity to inhibit TTRA81V acid- and mechanical force-induced fibril formation, albeit less effectively than with TTRWT. Chromatographic assessment of the patient's serum TTR tetramers indicated a slightly lower concentration (3.0 μM) before oral administration of Tafamidis compared with the normal range (3.6-7.2 μM).

CONCLUSIONS

We identified a patient with hATTR-CM who possesses a rare TTRA81V mutation solely associated with cardiac complications. The slightly reduced kinetic stability of this mutation indicates its late-onset nature and contributes to the gradual progression of the disease.

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.

Detection of transthyretin amyloid cardiomyopathy by automated data extraction from electronic health records

AIMS

Transthyretin amyloid cardiomyopathy (ATTR-CM), a progressive and fatal cardiomyopathy, is frequently misdiagnosed or entails diagnostic delays, hindering patients from timely treatment. This study aimed to generate a systematic framework based on data from electronic health records (EHRs) to assess patients with ATTR-CM in a real-world population of heart failure (HF) patients. Predictive factors or combinations of predictive factors related to ATTR-CM in a European population were also assessed.

METHODS AND RESULTS

Retrospective unstructured and semi-structured data from EHRs of patients from OLV Hospital Aalst, Belgium (2012-20), were processed using natural language processing (NLP) to generate an Observational Medical Outcomes Partnership Common Data Model database. NLP model performance was assessed on a random subset of EHRs by comparing algorithm outputs to a physician-generated standard (using precision, recall, and their harmonic mean, or F1-score). Of the 3127 HF patients, 103 potentially had ATTR-CM (age 78 ± 9 years; male 55%; ejection fraction of 48% ± 16). The mean diagnostic delay between HF and ATTR-CM diagnosis was 1.8 years. Besides HF and cardiomyopathy-related phenotypes, the strongest cardiac predictor was atrial fibrillation (AF; 72% in ATTR-CM vs. 60% in non-ATTR-CM, P = 0.02), whereas the strongest non-cardiac predictor was carpal tunnel syndrome (21% in ATTR-CM vs. 3% in non-ATTR-CM, P < 0.001). The strongest combination predictor was AF, joint disorders, and HF with preserved ejection fraction (29% in ATTR-CM vs. 18% in non-ATTR-CM: odds ratio = 2.03, 95% confidence interval = 1.28-3.22).

CONCLUSIONS

Not only well-known variables associated with ATTR-CM but also unique combinations of cardiac and non-cardiac phenotypes are able to predict ATTR-CM in a real-world HF population, aiding in early identification of ATTR-CM patients.

A Comprehensive Review on Chemistry and Biology of Tafamidis in Transthyretin Amyloidosis

Transthyretin amyloid cardiomyopathy and Transthyretin amyloid peripheral neuropathy are progressive disease conditions caused by Transthyretin amyloidosis (ATTR) fibril infiltration in the tissue. Transthyretin (TTR) protein misfolding and amyloid fibril deposits are pathological biomarkers of ATTR-related disorders. There are various treatment strategies targeting different stages in pathophysiology. One such strategy is TTR tetramer stabilization. Recently, a new TTR tetramer stabilizer, tafamidis, has been introduced that reduces the protein misfolding and amyloidosis and, consequently, disease progression in ATTR cardiomyopathy and peripheral neuropathy. This review will provide a comprehensive overview of the literature on tafamidis discovery, development, synthetic methods, pharmacokinetics, analytical methods and clinical trials. Overall, 7 synthetic methods, 5 analytical methods and 23 clinical trials have been summarized from the literature.

Tafamidis treatment in patients with transthyretin amyloid cardiomyopathy: a systematic review and meta-analysis

Background

Previous studies have reported that tafamidis treatment was associated with better outcomes in patients with transthyretin amyloid cardiomyopathy (ATTR-CM) compared with those without tafamidis treatment. Therefore, we aimed to systematically assess the association of tafamidis treatment with outcomes in patients with ATTR-CM.

Methods

The protocol for this systematic review and meta-analysis was registered in the PROSPERO (CRD42022381985). Pubmed, Ovid Embase, Scopus, Cochrane Library, and Web of Science were interrogated to identify studies that evaluated the impact of tafamidis on prognosis in ATTR-CM, from January 1, 2000 to June 1, 2023. A random-effects model was used to determine the pooled risk ratio (RR) for the adverse endpoints. In addition, the main outcomes included all-cause death or heart transplantation, the composite endpoints included all-cause death, heart transplantation, cardiac-assist device implantation, heart failure exacerbations, and hospitalization.

Findings

Fifteen studies comprising 2765 patients (mean age 75.9 ± 9.3 years; 83.7% male) with a mean follow-up duration of 18.7 ± 17.1 months were included in the meta-analysis. There was a decrease in left ventricular ejection fraction (LVEF) (standard mean differences (SMD: -0.17; 95% confidence interval (CI), -0.31 to -0.03; P = 0.02) but were no significant differences in intraventricular septum (IVS) thickness or global longitudinal strain (GLS) after tafamidis treatment. However, subgroup analysis showed no significant deterioration in LVEF in the patients with wild-type ATTR after tafamidis treatment (SMD: -0.11; 95% CI, -0.34 to 0.12, P = 0.34). In addition, the group with tafamidis treatment had a decreased risk for all-cause death or heart transplantation compared to patients without treatment (the pooled RR, 0.44; 95% CI, 0.31-0.65; P < 0.01). Subgroup analysis showed that there was no significant difference of tafamidis on the outcomes in patients with wild-type or hereditary ATTR (RR, 0.44; 95% CI, 0.27-0.73 versus 0.21, 95% CI, 0.11-0.40, P = 0.08). Furthermore, tafamidis treatment was associated with a lower risk of the composite endpoint (RR, 0.57; 95% CI, 0.42-0.77; P < 0.01).

Interpretation

Our findings suggested that there was no significant deterioration in LVEF in the patients with wild-type ATTR after tafamidis treatment. In addition, tafamidis treatment was associated with a low risk of all-cause death and adverse cardiovascular events.

Funding

This work was supported by grants from the Natural Science Foundation of Sichuan Province [Grant Number: 23NSFSC4589] and the National Natural Science Foundation of China [Grant Number: 82202248].

British Society of Echocardiography guideline for the transthoracic echocardiographic assessment of cardiac amyloidosis

These guidelines form an update of the BSE guideline protocol for the assessment of restrictive cardiomyopathy (Knight et al. in Echo Res Prac, 2013). Since the original recommendations were conceived in 2013, there has been an exponential rise in the diagnosis of cardiac amyloidosis fuelled by increased clinician awareness, improvements in cardiovascular imaging as well as the availability of new and effective disease modifying therapies. The initial diagnosis of cardiac amyloidosis can be challenging and is often not clear-cut on the basis of echocardiography, which for most patients presenting with heart failure symptoms remains the first-line imaging test. The role of a specialist echocardiographer will be to raise the suspicion of cardiac amyloidosis when appropriate, but the formal diagnosis of amyloid sub-type invariably requires further downstream testing. This document seeks to provide a focused review of the literature on echocardiography in cardiac amyloidosis highlighting its important role in the diagnosis, prognosis and screening of at risk individuals, before concluding with a suggested minimum data set, for use as an aide memoire when reporting.

Usefulness of automatic assessment for longitudinal strain to diagnose wild-type transthyretin amyloid cardiomyopathy

Background

Left ventricular (LV) apical sparing by transthoracic echocardiography (TTE) has not been widely accepted to diagnose transthyretin amyloid cardiomyopathy (ATTR-CM), because it is time consuming and requires a level of expertise. We hypothesized that automatic assessment may be the solution for these problems.

Methods-and-Results

We enrolled 63 patients aged ≥70 years who underwent ^99mTc-labeled pyrophosphate (^99mTc-PYP) scintigraphy on suspicion of ATTR-CM and performed TTE by EPIQ7G, and had enough information for two-dimensional speckle tracking echocardiography at Kumamoto University Hospital from January 2016 to December 2019. LV apical sparing was described as a high relative apical longitudinal strain (LS) index (RapLSI). Measurement of LS was repeated using the same apical images with three different measurement packages as follows: (1) full-automatic assessment, (2) semi-automatic assessment, and (3) manual assessment. The calculation time for full-automatic assessment (14.7 ± 1.4 sec/patient) and semi-automatic assessment (66.7 ± 14.4 sec/patient) were significantly shorter than that for manual assessment (171.2 ± 59.7 sec/patient) (p < 0.01 for both). Receiver operating characteristic curve analysis showed that the area under curve of the RapLSI evaluated by full-automatic assessment for predicting ATTR-CM was 0.70 (best cut-off point; 1.14 [sensitivity 63%, specificity 81%]), by semi-automatic assessment was 0.85 (best cut-off point; 1.00 [sensitivity, 66%; specificity, 100%]) and by manual assessment was 0.83 (best cut-off point; 0.97 [sensitivity, 72%; specificity, 97%]).

Conclusion

There was no significant difference between the diagnostic accuracy of RapLSI estimated by semi-automatic assessment and that estimated by manual assessment. Semi-automatically assessed RapLSI is useful to diagnose ATTR-CM in terms of rapidity and diagnostic accuracy.

Pitfalls for the non-invasive diagnosis of wild-type transthyretin amyloid cardiomyopathy in a young adult: a case report

Background

Using technetium (Tc)-labelled pyrophosphate (PYP) cardiac scintigraphy, a non-invasive diagnosis of transthyretin amyloid (ATTR) cardiomyopathy can be made without histopathological confirmation. In patients suspected of ATTR cardiomyopathy, however, atypical presentations may necessitate further investigation.

Case summary

A 30-year-old man with hypertension and end-stage renal disease on peritoneal dialysis presented with progressive exertional dyspnoea. Left ventricular hypertrophy (LVH) with a maximal end-diastolic wall thickness up to 16 mm was detected on echocardiography. Speckle-tracking analysis revealed a reduced longitudinal strain of left ventricle with a relative apical sparing pattern. Although the absence of monoclonal gammopathy, a grade 3 myocardial uptake in ^99mTc-PYP cardiac scintigraphy, and negative TTR gene mutation inferred the diagnosis of wild-type ATTR, the relative youth of the patient still raised concerns regarding the diagnosis. Under clinical doubt, he underwent further testing. In non-contrast cardiac magnetic resonance (CMR) with native T1 mapping, the native T1 myocardial value was within the normal range. In endomyocardial biopsy (EMB), there was no evidence of amyloid deposition, negative Congo red staining, and no immunohistochemical evidence of transthyretin expression. These results excluded the diagnosis of ATTR cardiomyopathy and prevented subsequent unnecessary treatments.

Discussion

When patients with unexplained LVH meet the non-invasive diagnostic criteria for ATTR cardiomyopathy, an EMB should be considered in selected cases. Patients presenting at an atypical age for wild-type ATTR cardiomyopathy, absence of extracardiac symptoms/signs or classic electrocardiogram features for cardiac amyloidosis should be suspected of another diagnosis and require further CMR or EMB to confirm.

Clinical characteristics, outcome, and therapeutic effect of tafamidis in wild-type transthyretin amyloid cardiomyopathy

AIMS

Tafamidis improves prognosis in patients with transthyretin amyloid cardiomyopathy (ATTR-CM). However, real-world data on the therapeutic effect of tafamidis are lacking. This study aimed to evaluate the clinical course, outcomes, and effectivity monitoring of the therapeutic effect of tafamidis in patients with ATTR-CM.

METHODS AND RESULTS

This is a single-centre, retrospective observational study. We evaluated the clinical characteristics and outcomes in 125 consecutive patients with wild-type ATTR-CM (ATTRwt-CM) treated with tafamidis (treatment group) and 55 untreated patients (treatment-naïve group). We monitored the therapeutic effect of tafamidis for 12 months by evaluating serial cardiac biomarker and imaging findings. The treatment group had significantly more favourable outcome in all-cause mortality and hospitalization due to heart failure than the treatment-naïve group in both the entire cohort (P < 0.01) and the propensity score-matched cohort (P < 0.05). Kaplan-Meier survival curves showed that tafamidis treatment significantly reduced all-cause mortality (P = 0.03, log-rank test), with the curves diverging after approximately 18 months of treatment in the propensity score-matched cohort. On inverse probability of treatment weighting analysis, tafamidis treatment showed a reduced all-cause mortality [hazard ratio (HR), 0.31; 95% confidence interval (CI), 0.11-0.93; P = 0.04]. High-sensitivity cardiac troponin T (hs-cTnT) > 0.05 ng/mL, B-type natriuretic peptide (BNP) > 250 pg/mL, and estimated glomerular filtration rate (eGFR) < 45 mL/min/1.73 m² scored 1 point each. Multivariate logistic regression analysis revealed that a high score (2-3 points) was a significantly poor prognostic factor of composite clinical outcomes, including all-cause death and hospitalization for heart failure (HR, 1.55; 95% CI, 1.22-1.98; P < 0.01) for patients in the treatment group. After 12 months of tafamidis treatment, hs-cTnT levels decreased significantly [0.054 (0.036-0.082) vs. 0.044 (0.033-0.076); P = 0.002], with no significant changes in BNP levels, echocardiographic parameters, native T1 value, and extracellular volume fraction on cardiac magnetic resonance imaging.

CONCLUSIONS

The prognosis of patients with ATTRwt-CM treated with tafamidis was more favourable than that of untreated patients. Patient stratification combined with biomarkers (hs-cTnT, BNP, and eGFR) predicted clinical outcomes. hs-cTnT may be a useful biomarker for evaluating the therapeutic effect of tafamidis.

Impact of Tafamidis on Echocardiographic Cardiac Function of Patients With Transthyretin Cardiac Amyloidosis

BACKGROUND

The efficacy of a therapy for patients with transthyretin amyloid cardiomyopathy (ATTR-CM) has not been proven, but tafamidis has been associated with favorable outcomes. However, echocardiographic details of the association of tafamidis with cardiac morphology remain undetermined. Moreover, whether the efficacy of tafamidis varies with the degree of cardiac involvement remains unknown. Using echocardiography, this study investigated the impact of tafamidis on the cardiac morphology of patients with ATTR-CM.Methods and Results: Of 52 consecutive patients with biopsy-proven ATTR-CM at Kobe University Hospital, we included 41 for whom details of follow-up echocardiographic examinations after the administration of tafamidis were available. All patients underwent standard and speckle-tracking echocardiography before and a mean (±SD) of 16±8 months after the administration of tafamidis. No significant changes were observed in any representative echocardiographic parameters after the administration of tafamidis. Furthermore, there were no significant changes observed in subgroup analyses (e.g., left ventricular [LV] ejection fraction ≥50% vs. <50%; LV mass index <150 vs. ≥150 g/m²; New York Heart Association Class I-II vs. Class III; age ≥80 vs. <80 years).

CONCLUSIONS

Tafamidis may prevent worsening of various representative echocardiographic parameters of patients with ATTR-CM. This effect is also seen in patients with relatively advanced disease and in those who are elderly.

An echo score raises the suspicion of cardiac amyloidosis in Chinese with heart failure with preserved ejection fraction

AIMS

Transthyretin cardiac amyloidosis (ATTR-CA) has been realized as an important cause of heart failure with preserved ejection fraction (HFpEF). We aim to provide insights into its prevalence in Chinese HFpEF patients, which is not known to date, using increased wall thickness (IWT) score by echocardiography.

METHODS

Consecutive patients with HFpEF (EF ≥ 40%) and IWT (≥12 mm) were prospectively screened. Echocardiography was performed, and the IWT score incorporated relative wall thickness, E/e' ratio, longitudinal strains, and tricuspid annular plane systolic excursion, and septal apical-to-base ratio was calculated. ATTR-CA was defined as score ≥8 in the absence of serum and urine free light chain.

RESULTS

Six hundred twenty-four HFpEF patients from January 2019 to December 2021 were enrolled, of which 65.2% were males and the median (interquartile range [IQR]) age was 66 (IQR 57, 73) years. Thirty-three patients (5.3%, 95% CI 3.5-7.0%) were with score ≥8, and 33.3% were females. They were younger (58 vs. 69 years, P < 0.001), had higher NT-proBNP (6525.0 vs. 1741.5 pg/mL, P < 0.001) and troponin I (105.2 vs. 27.7 pg/mL, P = 0.001) level, and lower LVEF (47% vs. 57%, P < 0.001) compared with the patients with score <5. In the internal cohort (82 patients) who had undergone scintigraphy, the IWT score ≥8 was shown to have a sensitivity of 85.7% (95% CI 56.2-97.5%) and a specificity of 92.6% (95% CI 83.0-97.3%) for diagnosing CA, and the IWT score <5 had great accuracy in excluding CA with the negative predictive value of 100%, supporting the clinical usefulness of the IWT score to guide further dedicated testing for ATTR-CA.

CONCLUSIONS

The IWT score by echocardiography was an excellent tool for screening ATTR-CA in HFpEF. In Chinese HFpEF patients associated with a hypertrophic phenotype, the proportion of highly suspected ATTR-CA as detected by IWT score ≥8 was 5.3%, lower than the reported prevalence of ATTR-CA in non-Asian patients with the disease.

Utility of left atrial and ventricular strain for diagnosis of transthyretin amyloid cardiomyopathy in aortic stenosis

Aims

To clarify the usefulness of left atrial (LA) function and left ventricular (LV) function obtained by two‐dimensional (2D) speckle tracking echocardiography to diagnose concomitant transthyretin amyloid cardiomyopathy (ATTR‐CM) in patients with aortic stenosis (AS).

Methods and results

We analysed 72 consecutive patients with moderate to severe AS who underwent ^99mTc‐pyrophosphate (PYP) scintigraphy at Kumamoto University Hospital from January 2012 to September 2020. We divided these 72 patients into 2 groups based on their ^99mTc‐PYP scintigraphy positivity or negativity. Among 72 patients, 16 patients (22%) were positive, and 56 patients (78%) were negative for ^99mTc‐PYP scintigraphy. In clinical baseline characteristics, natural logarithm troponin T was significantly higher in the ^99mTc‐PYP scintigraphy‐positive than scintigraphy‐negative group (−2.9 ± 0.5 vs. −3.5 ± 0.8 ng/mL, P < 0.05). In conventional echocardiography, the severity of AS was not significantly different between these two groups. In 2D speckle tracking echocardiography, the relative apical longitudinal strain (LS) index (RapLSI) [apical LS/ (basal LS + mid LS)] was significantly higher (1.09 ± 0.49 vs. 0.78 ± 0.23, P < 0.05) and the peak longitudinal strain rate (LSR) in LA was significantly lower in the ^99mTc‐PYP scintigraphy‐positive than scintigraphy‐negative group (0.36 ± 0.14 vs. 0.55 ± 0.20 s⁻¹, P < 0.05). Multivariable logistic analysis revealed the peak LSR in LA and RapLSI were significantly associated with ^99mTc‐PYP scintigraphy positivity. Receiver operating characteristic analysis showed that the area under the curve (AUC) of the peak LSR in LA for ^99mTc‐PYP scintigraphy positivity was 0.79 and that the best cut‐off value of the peak LSR in LA was 0.47 s⁻¹ (sensitivity: 78.6% and specificity: 72.3%). The AUC of RapLSI for ^99mTc‐PYP scintigraphy positivity was 0.69, and the cut‐off value of RapLSI was decided as 1.00 (sensitivity: 43.8% and specificity: 87.5%) according to the previous report. The ^99mTc‐PYP scintigraphy positivity in patients with RapLSI ≥ 1.0 and the peak LSR in LA ≤ 0.47 s⁻¹ was 83.3% (5/6), and the ^99mTc‐PYP scintigraphy negativity in patients with RapLSI < 1.0 and the peak LSR in LA > 0.47 s⁻¹ was 96.6% (28/29).

Conclusions

Left atrial and LV strain analysis were significantly associated with ^99mTc‐PYP scintigraphy positivity in ATTR‐CM patients with moderate to severe AS. The combination of the peak LSR in LA and RapLSI might be a useful predictor of the presence of ATTR‐CM in patients with moderate to severe AS.

Preclinical diagnosis of wild-type transthyretin amyloid cardiomyopathy in a patient undergoing carpal tunnel release

Wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM) has received increased attention because of its novel treatment options. Carpal tunnel syndrome (CTS) is known as early symptoms in transthyretin amyloidosis (ATTR) preceding cardiac involvement and one of the "red flags" for ATTR-CM. A 64-year-old man underwent carpal tunnel release for carpal tunnel syndrome at 62 years. He was diagnosed with wild-type ATTR due to deposition of transthyretin (TTR) amyloid in flexor tenosynovium specimens and no TTR gene mutation. Examination for detection of cardiac involvement was performed after the operation, and there were no definitive findings of ATTR-CM; however, an early stage of ATTR-CM remained a possibility. Serial image evaluation and biomarker analysis revealed positive findings for ATTR-CM, and we performed an endomyocardial biopsy, resulting in the detection of amyloid deposition. He was diagnosed with ATTRwt-CM 2 years after the operation, and even then, he had no heart failure symptoms. Early diagnosis and treatment are important for the improvement of clinical outcomes in patients with ATTRwt-CM. TTR deposition in the ligaments or tendons is often observed in patients with CTS and should be considered at high risk of future ATTR-CM. Serial follow-up of these patients may enable the diagnosis of preclinical ATTR-CM. <Learning objective: Bilateral carpal tunnel syndrome (CTS) patients with transthyretin deposition in surgically-excised specimens are considered to be at high risk of future transthyretin amyloid cardiomyopathy (ATTR-CM). Serial evaluation of imaging results and cardiac biomarkers are useful for the diagnosis of preclinical ATTR-CM.>.

Natural history and progression of transthyretin amyloid cardiomyopathy: insights from ATTR-ACT

Aims

Transthyretin amyloid cardiomyopathy (ATTR‐CM) is a progressive, fatal disorder that remains underdiagnosed. The Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR‐ACT) was the first large clinical trial to include both wild‐type (ATTRwt) and hereditary (ATTRv) patients. A description of the natural history of ATTR‐CM, utilizing data from placebo‐treated patients in ATTR‐ACT, will provide a greater understanding of presentation and progression of ATTR‐CM and may aid in disease awareness, earlier diagnosis and treatment monitoring.

Methods and results

Changes in clinical endpoints (mortality, cardiovascular [CV]‐related hospitalizations, 6‐min walk test [6MWT] distance and Kansas City Cardiomyopathy Questionnaire Overall Summary [KCCQ‐OS] score) from baseline to Month 30 in the 177 patients (134 ATTRwt, 43 ATTRv) who received placebo in ATTR‐ACT were assessed. ATTRwt patients tended to have less severe disease at baseline. Over the duration of ATTR‐ACT, there were 76 (42.9%) all‐cause deaths, and 107 (60.5%) patients had a CV‐related hospitalization. There was a lower proportion of all‐cause deaths in ATTRwt (49, 36.6%) than ATTRv (27, 62.8%). There was a similar, steady decline in mean (SD) 6MWT distance from baseline to Month 30 in ATTRwt (93.9 [93.7] m) and ATTRv (89.1 [107.2] m) patients. The decline in mean (SD) KCCQ‐OS score was less severe in ATTRwt (13.8 [20.7]) than ATTRv (21.0 [26.4]) patients.

Conclusions

Patients with ATTR‐CM experience a severe, progressive disease. In ATTR‐ACT, placebo‐treated patients with ATTRv, compared with ATTRwt, had more severe disease at baseline, and their disease progressed more rapidly as shown by mortality, hospitalizations and quality of life over time.

Expert consensus on the monitoring of transthyretin amyloid cardiomyopathy

Transthyretin amyloid cardiomyopathy (ATTR-CM) is a life-threatening condition with a heterogeneous clinical presentation. The recent availability of treatment for ATTR-CM has stimulated increased awareness of the disease and patient identification. Stratification of patients with ATTR-CM is critical for optimal management and treatment; however, monitoring disease progression is challenging and currently lacks best-practice guidance. In this report, experts with experience in treating amyloidosis and ATTR-CM developed consensus recommendations for monitoring the course of patients with ATTR-CM and proposed meaningful thresholds and frequency for specific parameters. A set of 11 measurable features across three separate domains were evaluated: (i) clinical and functional endpoints, (ii) biomarkers and laboratory markers, and (iii) imaging and electrocardiographic parameters. Experts recommended that one marker from each of the three domains provides the minimum requirements for assessing disease progression. Assessment of cardiac disease status should be part of a multiparametric evaluation in which progression, stability or improvement of other involved systems in transthyretin amyloidosis should also be considered. Additional data from placebo arms of clinical trials and future studies assessing ATTR-CM will help to elucidate, refine and define these and other measurements.

Impact of Delayed Diagnosis and Misdiagnosis for Patients with Transthyretin Amyloid Cardiomyopathy (ATTR-CM): A Targeted Literature Review

INTRODUCTION

Transthyretin amyloid cardiomyopathy (ATTR-CM) is a progressive, fatal and under-recognized disease. This targeted literature review assessed the extent and consequences of diagnostic delay and misdiagnosis in ATTR-CM.

METHODS

The Embase database was searched together with proceedings of eight cardiology conferences to identify publications or abstracts on ATTR-CM. Outcomes of interest were time from symptom onset to diagnosis, rates of delayed diagnosis and misdiagnosis, and costs, healthcare resource use or clinical outcomes whilst undiagnosed/misdiagnosed.

RESULTS

Twenty-three articles were included. Weighted means of reported mean and median diagnostic delays were 6.1 and 3.4 years for wild-type (ATTRwt-CM) and 5.7 and 2.6 years for hereditary (ATTRv-CM). Misdiagnosis occurred in 34-57% of patients when reported. Evaluation and misdiagnosis by multiple healthcare providers before receiving an ATTR-CM diagnosis was common, and there was evidence that patients undergo unnecessary or inappropriate evaluations or treatments while misdiagnosed. Diagnostic "red flags" were reported to be underused. Data on the consequences of delay for patients and health systems were sparse, but given the progressive nature of ATTR-CM, delay is likely to have adverse consequences.

CONCLUSION

ATTR-CM patients commonly experience diagnostic delay and misdiagnosis. Efforts are required to provide timely diagnosis so that patients can benefit from earlier access to new disease-modifying therapies.

Efficacy and safety of tafamidis doses in the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT) and long-term extension study

Aims

Tafamidis is an effective treatment for transthyretin amyloid cardiomyopathy (ATTR‐CM) in the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR‐ACT). While ATTR‐ACT was not designed for a dose‐specific assessment, further analysis from ATTR‐ACT and its long‐term extension study (LTE) can guide determination of the optimal dose.

Methods and results

In ATTR‐ACT, patients were randomized (2:1:2) to tafamidis 80 mg, 20 mg, or placebo for 30 months. Patients completing ATTR‐ACT could enrol in the LTE (with placebo‐treated patients randomized to tafamidis 80 or 20 mg; 2:1) and all patients were subsequently switched to high‐dose tafamidis. All‐cause mortality was assessed in ATTR‐ACT combined with the LTE (median follow‐up 51 months). In ATTR‐ACT, the combination of all‐cause mortality and cardiovascular‐related hospitalizations over 30 months was significantly reduced with tafamidis 80 mg (P = 0.0030) and 20 mg (P = 0.0048) vs. placebo. All‐cause mortality vs. placebo was reduced with tafamidis 80 mg [Cox hazards model (95% confidence interval): 0.690 (0.487–0.979), P = 0.0378] and 20 mg [0.715 (0.450–1.137), P = 0.1564]. The mean (standard error) change in N‐terminal pro‐B‐type natriuretic peptide from baseline to Month 30 was −1170.51 (587.31) (P = 0.0468) with tafamidis 80 vs. 20 mg. In ATTR‐ACT combined with the LTE there was a significantly greater survival benefit with tafamidis 80 vs. 20 mg [0.700 (0.501–0.979), P = 0.0374]. Incidence of adverse events in both tafamidis doses were comparable to placebo.

Conclusion

Tafamidis, both 80 and 20 mg, effectively reduced mortality and cardiovascular‐related hospitalizations in patients with ATTR‐CM. The longer‐term survival data and the lack of dose‐related safety concerns support tafamidis 80 mg as the optimal dose.

Clinical Trial Registration: ClinicalTrials.gov NCT01994889; NCT02791230.

Wild-type transthyretin amyloid cardiomyopathy complicated by spinal canal stenosis, carpal tunnel syndrome, and rotator cuff tears: a case report

Background

Wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM) is receiving increasing attention due to the availability of novel treatment options. Carpal tunnel syndrome (CTS) and lumbar spinal canal stenosis are known early symptoms of transthyretin (TTR) amyloidosis preceding the cardiac involvement and are considered as ‘Red Flags’ for transthyretin amyloid cardiomyopathy (ATTR-CM).

Case summary

A 67-year-old man with a history of lumbar spinal canal stenosis for the last 10 years, right rotator cuff tears for the last 4 years, and bilateral CTS for the last 1 year was scheduled for orthopaedic surgery for lumbar spinal canal stenosis. Investigations revealed severe left ventricular hypertrophy and hypertroponinaemia, which were suggestive of cardiac amyloidosis. Cardiac magnetic resonance imaging and ^99mTc-labelled pyrophosphate scintigraphy demonstrated positive findings for ATTR-CM. Transthyretin deposition was found in both the myocardium and the yellow ligamentum excised during surgery. There was no transthyretin mutation on genetic testing. The final diagnosis was ATTRwt-CM.

Discussion

Transthyretin deposition in the ligaments or tendons has been observed in a number of patients with CTS, spinal canal stenosis, and rotator cuff tears. These orthopaedic diseases are predictive for the future occurrence of ATTR-CM. In addition, the coexistence of these multiple diseases might strongly predict ATTR-CM. This knowledge needs to be shared with orthopaedicians and cardiologists for the early diagnosis of ATTR-CM.

Transthyretin amyloid cardiomyopathy in women: frequency, characteristics, and diagnostic challenges

Transthyretin amyloid cardiomyopathy (ATTR-CM) is a progressive, life-threatening disease characterized by deposition of insoluble amyloid fibrils in the myocardium, resulting in cardiac structural and functional abnormalities and ultimately heart failure. Disease frequency is reportedly lower in women than men, but sex-related differences have not been well established. We conducted a systematic literature review (SLR), based on PRISMA-P guidelines and registered with PROSPERO, to assess whether the epidemiology and clinical presentation of ATTR-CM differ between women and men. MEDLINE, Embase, and Cochrane databases and selected conference proceedings were searched (August 16, 2019) to identify observational and clinical studies reporting sex-specific data for patients with wild-type or hereditary ATTR-CM. Of 193 publications satisfying final eligibility criteria, 69 studies were included in our pooled analysis. Among the 4669 patients with ATTR-CM analyzed, 791 (17%) were women, including 174 (9%), 366 (29%), and 251 (18%) in studies of wild-type, hereditary, and undefined ATTR-CM, respectively. Data available on disease characteristics were limited and very heterogeneous, but trends suggested some cardiac structural/functional differences, i.e., lower interventricular septal and posterior wall thickness and left ventricular (LV) end diastolic diameter, and higher LV ejection fractions, in women versus men across ATTR-CM subtypes. Because LV wall thickness > 12 mm is generally the suggested threshold for ATTR-CM diagnosis in both sexes, smaller cardiac anatomy in women with the disease may lead to underdiagnosis. Additional research and studies are needed to elucidate potential disparities between sexes in ATTR-CM frequency, clinical characteristics, and underlying biological mechanisms. This study was registered within the International Prospective Register of Systematic Reviews (PROSPERO) database of the University of York (CRD42019146995).

Review of Transthyretin Silencers, Stabilizers, and Fibril Removal Agents in the Treatment of Transthyretin Cardiac Amyloid

PURPOSE OF REVIEW

To provide a functional review for practicing clinicians on the current and emerging treatment considerations for transthyretin (TTR) cardiac amyloidosis (ATTR-CA).

RECENT FINDINGS

Current treatment considerations are characterized as those silencing TTR translation, stabilizing TTR tetramers, and disrupting amyloid fibril deposition. Historically considered a rare disease state, ATTR-CA is increasingly recognized as an important mediator of heart failure morbidity and mortality. The emergence of widely available therapies for ATTR-CA has developed hope for patients where little was previously present. Thus, it is important that all cardiology clinicians have a functional understanding of the disease state and treatment options. This review will discuss agents within each of the above classes with expanded discussion on tafamidis given its favorable efficacy, safety, and availability. ATTR-CA diagnostic considerations are reviewed with regard to the identification of potential tafamidis candidates, and practical economic considerations are also reviewed.

Diagnostic performance of imaging investigations in detecting and differentiating cardiac amyloidosis: a systematic review and meta-analysis

Aims

The study aims to systematically assess the diagnostic performance of cardiac magnetic resonance (CMR) and nuclear scintigraphy (index tests) for the diagnosis and differentiation of subtypes of cardiac amyloidosis.

Methods and results

MEDLINE and Embase electronic databases were searched for studies evaluating the diagnostic performance of CMR or nuclear scintigraphy in detecting cardiac amyloidosis and subsequently in differentiating transthyretin amyloidosis (ATTR) from immunoglobulin light‐chain (AL) amyloidosis. In this meta‐analysis, histopathological examination of tissue from endomyocardial biopsy (EMB) or extra‐cardiac organs were reference standards. Pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio were calculated, and a random effects meta‐analysis was used to estimate diagnostic odds ratios. Methodological quality was assessed using a validated instrument. Of the 2947 studies identified, 27 met the criteria for inclusion. Sensitivity and specificity of CMR in diagnosing cardiac amyloidosis was 85.7% and 92.0% against EMB reference and 78.9% and 93.9% with any organ histology reference. Corresponding sensitivity and specificity of nuclear scintigraphy was 88.4% and 87.2% against EMB reference and 82.0% and 98.8% with histology from any organ. CMR was unable to reliably differentiate ATTR from AL amyloidosis (sensitivity 28.1–99.0% and specificity 11.0–60.0%). Sensitivity and specificity of nuclear scintigraphy in the differentiation of ATTR from AL amyloidosis ranged from 90.9% to 91.5% and from 88.6% to 97.1%. Pooled negative likelihood ratio and positive likelihood ratio for scintigraphy in this setting were 0.1 and 8, with EMB reference standard. Study quality assessed by QUADAS‐2 was generally poor with evidence of bias.

Conclusions

Cardiac magnetic resonance is a useful test for diagnosing cardiac amyloidosis but is not reliable in further classifying the disease. Nuclear scintigraphy offers strong diagnostic performance in both the detection of cardiac amyloidosis and differentiating ATTR from AL amyloidosis. Our findings support the use of both imaging modalities in a non‐invasive diagnostic algorithm that also tests for the presence of monoclonal protein.