Diagnosis of wild-type transthyretin amyloid cardiomyopathy in Japan: red-flag symptom clusters and diagnostic algorithm

Descriptive study of the clinical and myocardial status of a population with anatomopathological aortic valve amyloidosis

BACKGROUND

Aortic stenosis (AS) and transthyretin (ATTR) cardiac amyloidosis (CA) share the same clinical profiles and cardiac phenotype. Amyloid deposits have been frequently reported in aortic valves of patients with severe AS referred for surgical aortic valve replacement (SAVR). The aim of this study was to determine the clinical and myocardial status of patients with aortic valve amyloidosis after aortic valve surgery.

METHODS AND RESULTS

We performed a retrospective descriptive study of 46 patients who underwent SAVR for severe AS with amyloid deposits upon histological analysis. All patients were screened for cardiac involvement. Amyloid deposits typing was successful in 35 (76%) patients and 28 (80%) were ATTR. Two (4%) had positive bone scintigraphy and among the 5 myocardial biopsies performed during surgery, 80% were positive for ATTR deposits.

CONCLUSION

ATTR is the predominant type in the presence of amyloid deposits on the aortic valve after surgery for severe AS but is only rarely accompanied by cardiac uptake on bone scintigraphy. Early stages of myocardial involvement are frequent and myocardial biopsy is more sensitive for detection of mild amyloid deposits than bone scintigraphy. underdiagnosed by bone scintigraphy.

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.

Inverse correlation between age of onset and myocardial amyloid deposition quantified by 99mTc-PYP scintigraphy in patients with wild-type transthyretin amyloid cardiomyopathy

OBJECTIVE

Wild-type transthyretin amyloidosis cardiomyopathy (ATTRwt-CM) is increasingly recognized as a contributing factor to cardiac insufficiency in the elderly population. We aimed to identify the factors affecting age of onset of ATTRwt-CM, encompassing the assessment of amyloid deposition in myocardial tissue through the use of 99mTc-pyrophosphate (PYP) and clinical parameters.

METHODS

A retrospective investigation involving a consecutive cohort of 107 cases, each having been diagnosed with ATTRwt-CM confirmed through histopathological and genetic analysis, was performed. All patients underwent PYP scintigraphy, and the heart-to-contralateral (H/CL) ratio was calculated to measure amyloid deposition in the myocardium. Univariate and multivariate analyses were performed to identify independent predictors of the age of onset of ATTRwt-CM, considering the H/CL ratio and various clinical risk factors for heart failure.

RESULTS

Gender (p = 0.03), Creatinine (Cr) (r = 0.32, p < 0.01), hemoglobin (Hb) (r =  - 0.44, p < 0.01), albumin (Alb) (r =  - 0.32, p < 0.01), brain natriuretic peptide (BNP) (r = 0.21, p = 0.03), low-density lipoprotein-cholesterol (LDL-C) (r =  - 0.27, p < 0.01), and H/CL ratio (r =  - 0.44, p < 0.01) were all significantly associated with the onset age. In multiple regression analysis, the independent predictive factors for the onset age of ATTRwt-CM were identified as the H/CL ratio (p < 0.01), Hb (p < 0.01), and Cr (p < 0.01).

CONCLUSION

The H/CL ratio, Hb, and Cr independently affect age of onset in patients with ATTRwt-CM. The H/CL ratio is inversely correlated with age of onset, and may be the sole factor in the development of heart failure in early onset patients, while it may have a synergistic effect on heart failure with anemia and renal dysfunction in late-onset patients.

Deep vein thrombosis in a patient with wild-type transthyretin cardiac amyloidosis

Wild-type transthyretin cardiac amyloidosis (ATTRwt-CA) is a progressive myocardial disease characterized by an increased ventricular wall thickness. ATTRwt-CA is often accompanied by monoclonal gammopathy of undetermined significance (MGUS), as indicated by an abnormal serum-free light chain ratio or detection of monoclonal protein (M-protein) on serum immunofixation electrophoresis. Increasing evidence has emerged regarding the risk of venous thromboembolic disease in patients with MGUS. Herein, we report a case of ATTRwt-CA with M-protein, where the patient developed deep vein thrombosis (DVT). A 72-year-old man presented with gradual progressive swelling of the right lower extremity. He had undergone surgical treatment for bilateral carpal syndrome and lumbar spinal canal stenosis. He was diagnosed with DVT and severe left ventricular (LV) hypertrophy, and was treated with a direct factor Xa inhibitor. Given severe LV hypertrophy, the patient underwent further cardiac examinations. 99mTc-labelled pyrophosphate scintigraphy revealed grade 3 myocardial uptake. Serum immunofixation electrophoresis detected IgA-κ M-protein. An endomyocardial biopsy revealed amyloid deposits. Based on immunohistochemical staining and genetic testing, the patient was diagnosed as having ATTRwt-CA with IgA-κ M-protein. Therefore, clinicians should be aware that ATTRwt-CA is often associated with M-protein. Under these conditions, attention should be paid to both pathological issues.

Learning objective

Wild-type transthyretin cardiac amyloidosis (ATTRwt-CA) is often accompanied by monoclonal gammopathy of undetermined significance (MGUS), as indicated by an abnormal serum-free light chain ratio or detection of monoclonal protein (M-protein). Meanwhile, increasing evidence has emerged about the risk of deep vein thrombosis (DVT) in patients with MGUS. We report a case of ATTRwt-CA with M-protein, in which DVT developed. Under these conditions, paying attention to both pathological aspects is warranted.

Prevalence and Treatment of Arrhythmias in Patients With Transthyretin and Light-Chain Cardiac Amyloidosis

Background: Various types of arrhythmia are observed in patients with cardiac amyloidosis, but the prevalence of arrhythmia has not been fully investigated. This study investigated the prevalence and treatment of arrhythmias in patients with cardiac amyloidosis before the introduction of new agents for amyloidosis, such as tafamidis. Methods and Results: Of 53 patients who were histologically diagnosed with cardiac amyloidosis at 10 centers in western Japan between 2009 and 2021, 43 who were diagnosed on the basis of immunohistochemical staining were evaluated in this study. Of these 43 patients, 13 had immunoglobulin light-chain (AL) amyloidosis and 30 had transthyretin (ATTR) amyloidosis; further, 27 had atrial tachyarrhythmia, 13 had ventricular tachyarrhythmia, and 17 had bradyarrhythmia. Atrial fibrillation (AF) was the most common arrhythmia in patients with cardiac amyloidosis (n=24; 55.8%), especially among those with ATTR amyloidosis (70.0% of ATTR vs. 23.1% of AL). Eleven (25.6%) patients were treated with a cardiac implantable device. All 3 patients with pacemakers were alive at the last follow-up (median 76.7 months; interquartile range [IQR] 4.8-146.4 months). Of the 8 patients who underwent AF ablation, there was no recurrence in 6 (75%) after a median of 39.3 months (IQR 19.8-59.3 months). Conclusions: The prevalence of various arrhythmias was high in patients with cardiac amyloidosis. AF occurred most frequently in patients with cardiac amyloidosis, especially among patients with ATTR.

Echocardiographic score for the screening of cardiac amyloidosis with positive 99m technetium pyrophosphate scintigraphy result

INTRODUCTION

Speckle-tracking-derived strains in cardiac chambers may provide better solutions for transthyretin amyloid cardiomyopathy (ATTR-CM) screening. This study aimed to evaluate the efficacy of biventricular strain measurements using speckle tracking for screening ^99m Tc-pyrophosphate (^99m Tc-PYP) scintigraphy-positive cardiomyopathy, which is nearly equivalent to ATTR-CM.

METHODS

We performed a retrospective analysis of transthoracic echocardiographic studies using vendor-independent speckle tracking analysis in older patients (≥65 years) who underwent ^99m Tc-PYP scintigraphy to evaluate the etiology of suspected ATTR-CM in our institute between January 2019 and December 2022.

RESULTS

The entire cohort (n = 89) was divided into two subgroups positive ^99m Tc-PYP scan results (n = 34) and negative ^99m Tc-PYP scan results (n = 55). In the multivariate analysis, posterior wall thickness (p = .003, odds ratio [OR]:1.48, 95% confidence interval [CI]:1.14 -1.92), left ventricular longitudinal strain apical/basal ratio (LVLSapi/bas) (p = .015, OR: 2.78, 95% CI: 1.23-6.32, and right ventricular longitudinal strain (RVLS) (p = .003, OR: 1.15, 95% CI: 1.05 -1.26) were selected to be the most representative echocardiographic findings in ^99m Tc-PYP positive cardiomyopathy. The receiver operating characteristic analysis indicated that posterior wall thickness (p < .0001, area under the curve [AUC]: .821, cut-off value: 14.0 mm), LVLSapi/bas (p < .001, AUC: .802, cut-off value: 2,16), and RVLS (p < .001, AUC: .791, cut-off value: -18.7%) could significantly detect ^99m Tc-PYP positive results with an excellent credibility. Echocardiographic score points calculated using the summary of these three parameters in each patient revealed that a 2-point score had a fair sensitivity (85%) and an excellent specificity (93%), while a 1-point score had an excellent sensitivity (91%) and a modest specificity (53%).

CONCLUSION

Our proposed echocardiographic screening tool for ^99m Tc-PYP scintigraphy-positive cardiomyopathy may help clinicians manage patients with suspected ATTR-CM.

Epidemiology, Pathophysiology, Diagnosis, and Therapy of Heart Failure With Preserved Ejection Fraction in Japan

Heart failure (HF) with preserved ejection fraction (HFpEF) is a global health care problem, with diagnostic difficulty, limited treatment options and high morbidity and mortality rates. The prevalence of HFpEF is increasing because of the aging population and the increasing burden of cardiac and metabolic comorbidities, such as systemic hypertension, diabetes, chronic kidney disease, and obesity. The knowledge base is derived primarily from the United States and Europe, and data from Asian countries, including Japan, remain limited. Given that phenotypic differences may exist between Japanese and Western patients with HFpEF, careful characterization may hold promise to deliver new therapy specific to the Japanese population. In this review, we summarize the current knowledge regarding the epidemiology, pathophysiology and diagnosis of and the potential therapies for HFpEF in Japan.

Suspicion, screening, and diagnosis of wild-type transthyretin amyloid cardiomyopathy: a systematic literature review

Wild-type transthyretin amyloid cardiomyopathy (ATTRwt CM) is a more common disease than previously thought. Awareness of ATTRwt CM and its diagnosis has been challenged by its unspecific and widely distributed clinical manifestations and traditionally invasive diagnostic tools. Recent advances in echocardiography and cardiac magnetic resonance (CMR), non-invasive diagnosis by bone scintigraphy, and the development of disease-modifying treatments have resulted in an increased interest, reflected in multiple publications especially during the last decade. To get an overview of the scientific knowledge and gaps related to patient entry, suspicion, diagnosis, and systematic screening of ATTRwt CM, we developed a framework to systematically map the available evidence of (i) when to suspect ATTRwt CM in a patient, (ii) how to diagnose the disease, and (iii) which at-risk populations to screen for ATTRwt CM. Articles published between 2010 and August 2021 containing part of or a full diagnostic pathway for ATTRwt CM were included. From these articles, data for patient entry, suspicion, diagnosis, and screening were extracted, as were key study design and results from the original studies referred to. A total of 50 articles met the inclusion criteria. Of these, five were position statements from academic societies, while one was a clinical guideline. Three articles discussed the importance of primary care providers in terms of patient entry, while the remaining articles had the cardiovascular setting as point of departure. The most frequently mentioned suspicion criteria were ventricular wall thickening (44/50), carpal tunnel syndrome (42/50), and late gadolinium enhancement on CMR (43/50). Diagnostic pathways varied slightly, but most included bone scintigraphy, exclusion of light-chain amyloidosis, and the possibility of doing a biopsy. Systematic screening was mentioned in 16 articles, 10 of which suggested specific at-risk populations for screening. The European Society of Cardiology recommends to screen patients with a wall thickness ≥12 mm and heart failure, aortic stenosis, or red flag symptoms, especially if they are >65 years. The underlying evidence was generally good for diagnosis, while significant gaps were identified for the relevance and mutual ranking of the different suspicion criteria and for systematic screening. Conclusively, patient entry was neglected in the reviewed literature. While multiple red flags were described, high-quality prospective studies designed to evaluate their suitability as suspicion criteria were lacking. An upcoming task lies in defining and evaluating at-risk populations for screening. All are steps needed to promote early detection and diagnosis of ATTRwt CM, a prerequisite for timely treatment.

Diagnosis of wild-type transthyretin amyloid cardiomyopathy in Japan: red-flag symptom clusters and diagnostic algorithm

Wild‐type transthyretin amyloid cardiomyopathy (ATTRwt‐CM) is caused by the deposition of wild‐type transthyretin (TTR) amyloid fibrils in the heart. The age at diagnosis of ATTRwt‐CM is reported to be approximately 70–80 years, and patients commonly present with non‐disease‐specific cardiac abnormalities, such as heart failure with preserved ejection fraction and diastolic dysfunction. The disease can be fatal if left untreated, with an approximate survival of 3–5 years from diagnosis. An oral TTR stabilizer, tafamidis, has enabled early intervention for the treatment of ATTRwt‐CM. However, awareness of ATTRwt‐CM remains low, and misdiagnosis and a delay in diagnosis are common. This review discusses the epidemiology, characteristics, treatment strategy, and red‐flag symptoms and signs of ATTRwt‐CM based on the published literature, as well as recent advances in diagnostic modalities that enable early and accurate diagnosis of the disease. We also discuss an algorithm for early and accurate diagnosis of ATTRwt‐CM in daily clinical practice. In our diagnostic algorithm, a suspected diagnosis of ATTRwt‐CM should be triggered by unexplained left ventricular hypertrophy (LVH), which is LVH that cannot be explained by an increased afterload due to hypertension or valvular disease. In addition, heart failure symptoms, laboratory test results (N‐terminal pro‐B‐type natriuretic peptide, high‐sensitivity troponin T, or high‐sensitivity troponin I), electrocardiogram and imaging (echocardiogram or cardiac magnetic resonance) data, age (≥60 years), and medical history suggestive of ATTRwt‐CM (e.g. carpal tunnel syndrome) should be examined. Detailed examinations using bone scintigraphy and monoclonal protein detection tests followed by tissue biopsy, amyloid typing, and TTR genetic testing are warranted for a definite diagnosis of ATTRwt‐CM.