Cardiac Amyloidosis: Evolving Diagnosis and Management: A Scientific Statement From the American Heart Association

Aortic Valve Stenosis and Cardiac Amyloidosis: A Misleading Association

The association between aortic stenosis (AS) and cardiac amyloidosis (CA) is more frequent than expected. Albeit rare, CA, particularly the transthyretin (ATTR) form, is commonly found in elderly people. ATTR-CA is also the most prevalent form in patients with AS. These conditions share pathophysiological, clinical and imaging findings, making the diagnostic process very challenging. To date, a multiparametric evaluation is suggested in order to detect patients with both AS and CA and choose the best therapeutic option. Given the accuracy of modern non-invasive techniques (i.e., bone scintigraphy), early diagnosis of CA is possible. Flow-charts with the main CA findings which may help clinicians in the diagnostic process have been proposed. The prognostic impact of the combination of AS and CA is not fully known; however, new available specific treatments of ATTR-CA have changed the natural history of the disease and have some impact on the decision-making process for the management of AS. Hence the relevance of detecting these two conditions when simultaneously present. The specific features helping the detection of AS-CA association are discussed in this review, focusing on the shared pathophysiological characteristics and the common clinical and imaging hallmarks.

Transthyretin cardiac amyloidosis

Transthyretin amyloid cardiomyopathy (ATTR-CM) may be an under recognized cause of heart failure (HF). TTR amyloidosis can be inherited, caused by variants in the TTR gene (ATTRv) or by deposition of wild-type TTR protein (ATTRwt), leading to high mortality if untreated. We report the case of a patient with hereditary TTR amyloidosis and mixed phenotype (both cardiac and neurological involvement). We highlight the importance of multimodal imaging in the evaluation of these patients, as early diagnosis and treatment might lead to better outcome.

Age-related amyloidosis outside the brain: A state-of-the-art review

Inside and outside the brain, accumulation of amyloid fibrils plays key roles in the pathogenesis of fatal age-related diseases such as Alzheimer's and Parkinson's diseases and wild-type transthyretin amyloidosis. Although the incidence of all amyloidoses increases with age, for some types of amyloidosis aging is known as the main direct risk factor, and these types are typically diseases of elderly people. More than 10 different precursor proteins are known to cause age-associated amyloidosis; these proteins include amyloid β protein, α-synuclein, transthyretin, islet amyloid polypeptide, atrial natriuretic factor, and the newly discovered epidermal growth factor-containing fibulin-like extracellular matrix protein 1. Except for intracerebral amyloidoses, most age-related amyloidoses have been little studied. Indeed, in view of the increasing life expectancy in our societies, understanding how aging is involved in the process of amyloid fibril accumulation and the effects of amyloid deposits on the aging body is extremely important. In this review, we summarize current knowledge about the nature of amyloid precursor proteins, the prevalence, clinical manifestations, and pathogenesis of amyloidosis, and recent advances in our understanding of age-related amyloidoses outside the brain.

The Cooperative Relationship Between ASNC and JSNC

The Japanese Society of Nuclear Cardiology (JSNC) and the American Society of Nuclear Cardiology (ASNC) has a cooperative relationship through a memorandum of understanding (MOU), based on which we hold a joint symposium in the JSNC annual meeting in early summer. In addition to the joint symposium this year, a joint webinar was held in early June. The theme of the joint symposium and webinar was cardiac amyloidosis. We consider the success of this collaborative work to be the fruit of the close friendship between JSNC and ASNC. The cooperative relationship between JSNC and ASNC will continue to grow.

Echocardiographic assessment of cardiac amyloidosis

Cardiac amyloidosis, a form of infiltrative cardiomyopathy, is associated with poor prognosis in untreated patients. Early diagnosis is important for timely initiation of effective therapies. Despite advances in diagnostic modalities, it remains a challenging diagnosis, requiring high index of clinical suspicion. Echocardiography represents the first-line cardiac imaging modality for evaluation of heart failure and suspected cardiac amyloidosis. In this review, we discuss echocardiographic findings in cardiac amyloidosis.

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.

Differences in the characteristics and contemporary cardiac outcomes of patients with light-chain versus transthyretin cardiac amyloidosis

AIMS

To compare the baseline cardiovascular characteristics of immunoglobulin light-chain (AL) and amyloid transthyretin (ATTR) cardiac amyloidosis (CA) and to investigate patients' contemporary cardiac outcomes.

METHODS

Single-center analysis of clinical, laboratory, echocardiographic and cardiac magnetic resonance imaging (CMRi) characteristics of AL and ATTR-CA patients' cohort (years 2013-2020).

RESULTS

Included were 67 CA patients of whom 31 (46%) had AL-CA and 36 (54%) had ATTR-CA. Patients with ATTR-CA versus AL-CA were older (80 (IQR 70, 85) years versus 65 (IQR 60, 71) years, respectively, p<0.001) with male predominance (p = 0.038). Co-morbidities in ATTR-CA patients more frequently included diabetes mellitus (19% versus 3.0%, respectively, p = 0.060) and coronary artery disease (39% versus 10%, respectively, p = 0.010). By echocardiography, patients with ATTR-CA versus AL-CA had a trend to worse left ventricular (LV) ejection function (50 (IQR 40, 55)% versus 60 (IQR 45, 60)%, respectively, p = 0.051), yet comparable LV diastolic function. By CMRi, left atrial area (31 (IQR 27, 36)cm2 vs. 27 (IQR 23, 30)cm2, respectively, p = 0.015) and LV mass index (109 (IQR 96, 130)grams/m2 vs. 82 (IQR 72, 98)grams/m2, respectively, p = 0.011) were increased in patients with ATTR-CA versus AL-CA. Nevertheless, during follow-up (median 20 (IQR 10, 38) months), patients with AL-CA were more frequently admitted with heart failure exacerbations (HR 2.87 (95% CI 1.42, 5.81), p = 0.003) and demonstrated increased mortality (HR 2.51 (95%CI 1.19, 5.28), p = 0.015).

CONCLUSION

Despite the various similarities of AL-CA and ATTR-CA, these diseases have distinct baseline cardiovascular profiles and different heart failure course, thus merit tailored-cardiac management.

Amyloidosis: Multisystem Spectrum of Disease with Pathologic Correlation

Amyloidosis is a group of conditions defined by extracellular deposition of insoluble proteins that can lead to multiorgan dysfunction and failure. The systemic form of the disease is often associated with a plasma cell dyscrasia but may also occur in the setting of chronic inflammation, long-term dialysis, malignancy, or multiple hereditary conditions. Localized forms of the disease most often involve the skin, tracheobronchial tree, and urinary tract and typically require tissue sampling for diagnosis, as they may mimic many conditions including malignancy at imaging alone. Advancements in MRI and nuclear medicine have provided greater specificity for the diagnosis of amyloidosis involving the central nervous system and heart, potentially obviating the need for biopsy of the affected organ in certain circumstances. Specifically, a combination of characteristic findings at noninvasive cardiac MRI and skeletal scintigraphy in patients without an underlying plasma cell dyscrasia is diagnostic for cardiac transthyretin amyloidosis. Histologically, the presence of amyloid is denoted by staining with Congo red and a characteristic apple green birefringence under polarized light microscopy. The imaging features of amyloid vary across each organ system but share some common patterns, such as soft-tissue infiltration and calcification, that may suggest the diagnosis in the appropriate clinical context. The availability of novel therapeutics that target amyloid protein fibrils such as transthyretin highlights the importance of early diagnosis. Online supplemental material is available for this article. ^©RSNA, 2021.

Progress and challenges in the treatment of cardiac amyloidosis: a review of the literature

Cardiac amyloidosis is a restrictive cardiomyopathy determined by the accumulation of amyloid, which is represented by misfolded protein fragments in the cardiac extracellular space. The main classification of systemic amyloidosis is determined by the amyloid precursor proteins causing a very heterogeneous disease spectrum, but the main types of amyloidosis involving the heart are light chain (AL) and transthyretin amyloidosis (ATTR). AL, in which the amyloid precursor is represented by misfolded immunoglobulin light chains, can involve almost any system carrying the worst prognosis among amyloidosis patients. This has however dramatically improved in the last few years with the increased usage of the novel therapies such as proteasome inhibitors and haematopoietic cell transplantation, in the case of timely diagnosis and initiation of treatment. The treatment for AL is directed by the haematologist working closely with the cardiologist when there is a significant cardiac involvement. Transthyretin (TTR) is a protein that is produced by the liver and is involved in the transportation of thyroid hormones, especially thyroxine and retinol binding protein. ATTR results from the accumulation of transthyretin amyloid in the extracellular space of different organs and systems, especially the heart and the nervous system. Specific therapies for ATTR act at various levels of TTR, from synthesis to deposition: TTR tetramer stabilization, oligomer aggregation inhibition, genetic therapy, amyloid fibre degradation, antiserum amyloid P antibodies, and antiserum TTR antibodies. Treatment of systemic amyloidosis has dramatically evolved over the last few years in both AL and ATTR, improving disease prognosis. Moreover, recent studies revealed that timely treatment can lead to an improvement in clinical status and in a regression of amyloid myocardial infiltration showed by imaging, especially by cardiac magnetic resonance, in both AL and ATTR. However, treating cardiac amyloidosis is a complex task due to the frequent association between systemic congestion and low blood pressure, thrombo-embolic and haemorrhagic risk balance, patient frailty, and generally poor prognosis. The aim of this review is to describe the current state of knowledge regarding cardiac amyloidosis therapy in this constantly evolving field, classified as treatment of the cardiac complications of amyloidosis (heart failure, rhythm and conduction disturbances, and thrombo-embolic risk) and the disease-modifying therapy.

Improving contemporary outcomes following heart transplantation for cardiac amyloidosis

BACKGROUND

The incidence of systemic amyloidosis is rising, and there is a concomitant rise in heart transplant for an indication of cardiac amyloidosis.

METHODS

We utilized the Organ Procurement and Transplantation Network (OPTN) database to retrospectively assess survival and outcomes in adult patients undergoing heart transplant for cardiac amyloidosis from 1999 to 2019. We also compared survival among four distinct time periods: 1999-2001, 2002-2008, 2008-2015, 2016-2019.

RESULTS

Of 41,103 patients, 425 (1.03%) were transplanted for an indication of restrictive cardiomyopathy due to cardiac amyloidosis (RCM-Amyloidosis). The percent of all transplants occurring for RCM-Amyloidosis increased from 0.25% in the 1999-2001 era to 1.74% in the 2015-2019 era (p < .001). Across eras, Kaplan-Meier survival functions were comparable between RCM-Amyloidosis and non-RCM patients at 1 year (88% vs. 89%, p = .56) and at 5 years (72% vs. 77%, p = .092), but worse for RCM-Amyloidosis patients at 10 years (44% vs. 59%, p = .002). With adjustment for other clinical variables in multivariable Cox regression model, RCM-Amyloidosis was not associated with increased risk of death at 1 year (hazard ratio [HR] = 1.11, p = .56) or at 5 years (HR = 1.20, p = .18), but it was associated with increased risk of death at 10 years (HR = 1.35, p = .01). Cardiac amyloidosis was not associated with any morbidity outcomes following transplant, including graft failure, acute rejection, or hospitalization for infection or rejection.

CONCLUSIONS

Our data suggest a trend of improving survival among RCM-Amyloidosis patients compared with non-RCM patients across transplant eras, with current similarities in 1- and 5-year survival but a persistent, increased risk of mortality at 10 years.

Wild-type TTR amyloidosis among patients with unexplained heart failure and systolic LV dysfunction

AIM

Transthyretin cardiac amyloidosis (ATTR-CA) is an increasingly recognized cause of heart failure (HF) with preserved left ventricular ejection fraction (LVEF), typically presenting as restrictive cardiomyopathy. The potential co-existence of ATTR-CA with systolic heart failure has not been studied. The aim of this study is to describe the prevalence of ATTR-CA and its clinical characteristics in HF patients with reduced LVEF.

METHODS

Patients with an unexplained cause of LV systolic dysfunction were screened for ATTR-CA by a 99mTc-PYP planar scintigraphy. Patients in whom presence of ≥ 2 uptake was confirmed by SPECT imaging were included. Their clinical, laboratory and echocardiographic data were collected.

RESULTS

Out of 75 patients (mean age 65±12 years, LVEF 35.8±7.9%) included in this study, 7 (9.3%) patients (mean age 75±6 years, LVEF 32.0±8.3%) had ATTR-CA. Patients with ATTR-CA were more symptomatic at diagnosis (NYHA FC 3-4 (86% vs 35% (p = 0.03)) and had a more severe clinical course evident by recurrent hospitalizations for HF, and a need for intravenous diuretic treatment (p = 0.04 and p<0.01, respectively) at follow-up, compared with patients with no ATTR-CA. Patients with ATTR-CA had similar LVEF but a clear trend for larger LV mass index (157.1±60.6 g/m2 vs. 121.0±39.5 g/m2, p = 0.07) and a larger proportions of ATTR-CA patients had IVS thickness >13 mm (57.1% vs 13.1%, p = 0.02) as compared to HF patients with no ATTR-CA.

CONCLUSION

In our study, a meaningful percentage of patients with unexplained LV dysfunction had a co-existing ATTR-CA indicating that the clinical heterogeneity of ATTR-CA is much broader than previously thought.

From Clinical Clues to Final Diagnosis: The Return of Detective Work to Clinical Medicine in Cardiac Amyloidosis

Cardiac amyloidosis is frequently misdiagnosed, denying patients the opportunity for timely and appropriate management of the disease. The purpose of this review and case studies is to raise awareness of the diagnostic "red flags" associated with cardiac amyloidosis and the currently available non-invasive strategies for diagnosis. The review focuses on the identification of one of the two main types of cardiac amyloidosis, transthyretin amyloid cardiomyopathy, and non-invasive tools to distinguish this from light-chain amyloidosis. A diagnostic algorithm centered around the use of non-invasive imaging and laboratory analysis is presented. The algorithm generates four differential diagnoses for patients presenting with signs and symptoms consistent with cardiac amyloidosis. Case examples are presented, representing the four potential outcomes of diagnosis using the algorithm. The review provides a guide on how to recognize the often-overlooked presentations of this disease in clinical practice. Non-invasive imaging techniques and diagnostic tools that do not require the involvement of a specialty center have allowed for the improved diagnosis of cardiac amyloidosis. Timely diagnosis of this life-threatening disease is essential for optimal management and it is imperative that clinicians have a high index of suspicion for patients presenting with "red flag" symptoms.

Effects of sporadic transthyretin amyloidosis frequently on the gallbladder and the correlation between amyloid deposition in the gallbladder and heart: A forensic autopsy-based histopathological evaluation

The aim of the study is to evaluate the clinicopathological features of cholecystic ATTR deposition in patients with cardiac involvement, investigate the correlation of amyloid deposition severity in the gallbladder and the heart, and compare its prevalence in the gallbladder and other organs. Fifty patients with sporadic ATTR amyloidosis were identified. Of these, we evaluated 15 patients who underwent gallbladder sampling accurately. Among 10 patients (67%) with cholecystic deposition, six exhibited detectable deposition in the hematoxylin and eosin-stained specimens, and all of them displayed obstructive vascular deposition (VD). The severity of gall bladder VD was statistically correlated with that of cardiac VD and atrial interstitial deposition (ID). Additionally, all patients exhibiting cholecystic ID displayed severe ventricular and atrial IDs. In visceral organs excluding the heart, amyloid deposition was commonly observed in the lungs (93%), followed by the gastrointestinal tract (47%-80%), liver (60%) and periosteal tissues (53%). The involvement of the gallbladder was prevalent and comparable to that of the gastrointestinal tract. Moreover, the severity of cholecystic deposition was correlated with that of cardiac deposition. Therefore, pathologists should be aware that sporadic ATTR amyloidosis is a common condition and should not be overlooked.

Cardiac Amyloidosis: Multimodal Imaging of Disease Activity and Response to Treatment

Cardiac amyloidosis (CA) is a disease characterized by the deposition of misfolded protein deposits in the myocardial interstitium. Although advanced CA confers significant morbidity and mortality, the magnitude of deposition and ensuing clinical manifestations vary greatly. Thus, an improved understanding of disease pathogenesis at both cellular and functional levels would afford critical insights that may improve outcomes. This review will summarize contemporary therapies for the 2 major types of CA, transthyretin and light chain amyloidosis, and outline the capacity of imaging modalities to both diagnose CA, inform prognosis, and follow response to available therapies. We explore the current landscape of echocardiography, cardiac magnetic resonance, and bone scintigraphy in the assessment of functional and cellular parameters of dysfunction in CA throughout disease pathogenesis. Finally, we examine the impact of concurrent advances in both therapeutics and imaging on future research questions that improve our understanding of underlying disease mechanisms. Multimodal imaging in CA affords an indispensable tool to offer individualized treatment plans and improve outcomes in patients with CA.

Multidisciplinary Approaches for Transthyretin Amyloidosis

Amyloidosis caused by systemic deposition of transthyretin (TTR) is called ATTR amyloidosis and mainly includes hereditary ATTR (ATTRv) amyloidosis and wild-type ATTR (ATTRwt) amyloidosis. Until recently, ATTRv amyloidosis had been considered a disease in the field of neurology because neuropathic symptoms predominated in patients described in early reports, whereas advances in diagnostic techniques and increased recognition of this disease revealed the presence of patients with cardiomyopathy as a predominant feature. In contrast, ATTRwt amyloidosis has been considered a disease in the field of cardiology. However, recent studies have suggested that some of the patients with ATTRwt amyloidosis present tenosynovial tissue complications, particularly carpal tunnel syndrome, as an initial manifestation of amyloidosis, necessitating an awareness of this disease among neurologists and orthopedists. Although histopathological confirmation of amyloid deposits has traditionally been considered mandatory for the diagnosis of ATTR amyloidosis, the development of noninvasive imaging techniques in the field of cardiology, such as echocardiography, magnetic resonance imaging, and nuclear imaging, enabled nonbiopsy diagnosis of this disease. The mechanisms underlying characteristic cardiac imaging findings have been deciphered by histopathological studies. Novel disease-modifying therapies for ATTR amyloidosis, such as TTR stabilizers, short interfering RNA, and antisense oligonucleotides, were initially approved for ATTRv amyloidosis patients with polyneuropathy. However, the indications for the use of these disease-modifying therapies gradually widened to include ATTRv and ATTRwt amyloidosis patients with cardiomyopathy. Since the coronavirus disease 2019 (COVID-19) pandemic, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, occurred, the minimization of hospital visits and telemedicine have become increasingly important. As older age and cardiovascular disease are major factors associated with increased disease severity and mortality of COVID-19, many ATTR amyloidosis patients are at increased risk of disease aggravation when they are infected with SARS-CoV-2. From this viewpoint, close interspecialty communication to determine the optimal interval of evaluation is needed for the management of patients with ATTR amyloidosis.

Association of the transthyretin variant V122I with polyneuropathy among individuals of African ancestry

Hereditary transthyretin-mediated (hATTR) amyloidosis is an underdiagnosed, progressively debilitating disease caused by mutations in the transthyretin (TTR) gene. V122I, a common pathogenic TTR mutation, is found in 3-4% of individuals of African ancestry in the United States and has been associated with cardiomyopathy and heart failure. To better understand the phenotypic consequences of carrying V122I, we conducted a phenome-wide association study scanning 427 ICD diagnosis codes in UK Biobank participants of African ancestry (n = 6062). Significant associations were tested for replication in the Penn Medicine Biobank (n = 5737) and the Million Veteran Program (n = 82,382). V122I was significantly associated with polyneuropathy in the UK Biobank (odds ratio [OR] = 6.4, 95% confidence interval [CI] 2.6-15.6, p = 4.2 × 10-5), which was replicated in the Penn Medicine Biobank (OR = 1.6, 95% CI 1.2-2.4, p = 6.0 × 10-3) and Million Veteran Program (OR = 1.5, 95% CI 1.2-1.8, p = 1.8 × 10-4). Polyneuropathy prevalence among V122I carriers was 2.1%, 9.0%, and 4.8% in the UK Biobank, Penn Medicine Biobank, and Million Veteran Program, respectively. The cumulative incidence of common hATTR amyloidosis manifestations (carpal tunnel syndrome, polyneuropathy, cardiomyopathy, heart failure) was significantly enriched in V122I carriers compared with non-carriers (HR = 2.8, 95% CI 1.7-4.5, p = 2.6 × 10-5) in the UK Biobank, with 37.4% of V122I carriers having at least one of these manifestations by age 75. Our findings show that V122I carriers are at increased risk of polyneuropathy. These results also emphasize the underdiagnosis of disease in V122I carriers with a significant proportion of subjects showing phenotypic changes consistent with hATTR amyloidosis. Greater understanding of the manifestations associated with V122I is critical for earlier diagnosis and treatment.

Initial experience with percutaneous mitral valve repair in patients with cardiac amyloidosis

BACKGROUND

Percutaneous mitral valve repair (PMVR) is a therapeutic option for severe mitral regurgitation (MR) in patients with heart failure due to differential aetiologies. However, only little is known about the safety and efficacy of this procedure in patients with amyloid cardiomyopathy.

METHODS

Five patients with cardiac amyloidosis and moderate to severe or severe MR undergoing PMVR were analysed retrospectively and compared to seven patients with cardiac amyloidosis and severe MR without intervention. Clinical and functional data, renal function and cardiac biomarkers as well as established risk scores for cardiac amyloidosis were assessed. Primary endpoint was the reduction in MR one year after PMVR. Secondary endpoints were safety, overall mortality after 12 months compared with the control group, as well as changes in clinical and functional parameters.

RESULTS

Amyloidosis risk assessment documented amyloid cardiomyopathy at an advanced stage in all patients. Procedural, technical and device success of PMVR were all 100% and residual MR remained mild to moderate at 12 months follow-up (P = .038 vs before PMVR). Differences in survival compared with the control (no PMVR) group pointed to a possible survival benefit in the PMVR group (P = .02).

CONCLUSION

PMVR is a feasible and safe procedure in patients with cardiac amyloidosis and might carry a possible survival benefit in this patient group.

Multimodality imaging for the diagnosis of infiltrative cardiomyopathies

Infiltrative cardiomyopathies result from the deposition or anomalous storage of specific substances in the heart, leading to impaired cardiac function and heart failure. In this review, we describe the utility of a variety of imaging modalities for the diagnosis of infiltrative cardiomyopathies and provide algorithms for clinicians to use to evaluate patients with these disorders. We have divided infiltrative cardiomyopathies into two different categories: (1) infiltrative cardiomyopathies characterised by increased wall thickness (eg, cardiac amyloidosis and Anderson-Fabry disease (AFD)) and (2) infiltrative cardiomyopathies that can mimic ischaemic or dilated cardiomyopathies (eg, cardiac sarcoidosis (CS) and iron overload cardiomyopathy). Echocardiography is the first modality of choice for the evaluation of cardiomyopathies in either category, and the differential can be narrowed using cardiac magnetic resonance (CMR) and nuclear imaging techniques. The diagnosis of cardiac amyloidosis is supported with key findings seen on echocardiography, CMR and nuclear imaging, whereas AFD can be suggested by unique features on CMR. CMR and nuclear imaging are also important modalities for the diagnosis of CS, while iron overload cardiomyopathy is mostly diagnosed using tissue characterisation on CMR. Overall, multimodality imaging is necessary for the accurate non-invasive diagnosis of infiltrative cardiomyopathies, which is important to ensure appropriate treatment and prognostication.

AL type cardiac amyloidosis: a devastating fatal disease

Introduction

Cardiac amyloidosis is a rare entity with a grave prognosis. Due to the low index of suspicion secondary to non-specific symptoms, it is often diagnosed at an advanced stage with multi-organ involvement.

Methods

We report a case of systemic AL amyloidosis with predominant cardiac and renal involvement associated with multiple myeloma.

Case Summary

A 60-year-old male presented with progressive anasarca, orthopnea and weight gain over 8 months. On clinical examination, 3+ pitting edema was found in bilateral extremities and scrotum. Serum N-type proBNP and troponin T were elevated, and EKG showed diffuse low voltage QRS, right axis deviation, and 1^st degree AV block. Echocardiography revealed granular myocardium, biventricular hypertrophy, bi-atrial dilation and apical sparing pattern on global longitudinal strain which was suggestive of cardiac amyloidosis. Light chain assessment showed elevated kappa and lambda chains with kappa to lambda ratio of 16.2. Endomyocardial biopsy revealed AL type cardiac amyloidosis, and bone marrow biopsy confirmed the diagnosis of multiple myeloma. He received six cycles of bortezomib, cyclophosphamide, and dexamethasone but continued to deteriorate. He experienced an episode of cardiac arrest following which he had a return of spontaneous circulation but due to poor prognosis, the family opted for pursuing comfort measures only.

Conclusions

Cardiac involvement in AL type amyloidosis imparts significant morbidity and mortality. The management of cardiac amyloidosis entails a multidisciplinary approach with an emphasis on cardiology and oncology. Despite the novel diagnostic modalities and treatment regimens, the outcome for AL-type cardiac amyloidosis remains poor.

Current Challenges of Cardiac Amyloidosis Awareness among Romanian Cardiologists

Cardiac amyloidosis (CA) is a restrictive cardiomyopathy characterized by deposition of amyloid in the myocardium and recent studies revealed it is more frequently seen than we thought. Advances in diagnosis and treatment have been made over the last few years that make it desirable to diagnose CA without delay, and that may require extra education. An online survey was conducted among cardiologists from Romania, representing the first assessment of the knowledge of CA among them, with 195 cardiologists answering the questionnaire. There was a wide variation in their knowledge regarding CA. Our participants had limited experience with CA and reported a significant delay between first cardiac symptoms and diagnosis. We address the gaps in knowledge that were identified as educational opportunities in the main identified areas: prevalence and treatment of wild type transthyretin amyloidosis (ATTRwt), prevalence of variant transthyretin amyloidosis (ATTRv) in Romania, diagnosis of CA, the delay in CA diagnosis and available treatment options. Awareness among cardiologists is the most important challenge in diagnosing CA. Romanian cardiologists are partially aware of this topic, but there are still gaps in their knowledge. Educational programs can improve screening of patients with a high suspicion for this progressive condition the prognosis of which has been dramatically changed by the new treatment options.

2021 Advocacy Statements for the Role of 99mTc-Pyrophosphate Scintigraphy in the Diagnosis of Transthyretin Cardiac Amyloidosis: A Report of the Taiwan Society of Cardiology and the Society of Nuclear Medicine of the Republic of China

Transthyretin cardiac amyloidosis (ATTR-CM) is an increasingly recognized cause of heart failure with preserved ejection fraction. Favorable prognosis depends on early diagnosis and correct treatment strategy. Among patients for whom there is a high clinical suspicion of cardiac amyloidosis, 99mTc-labeled bone avid scintigraphy including 99mTc-pyrophosphate (PYP) scintigraphy may be of diagnostic and prognostic importance. Various international guidelines support the non-biopsy diagnosis of ATTR-CM using 99mTc-PYP scintigraphy, yet emphasize the gap in standardization of acquisition and imaging analysis protocols, as well as the appropriateness of its clinical use. Therefore, a joint expert consensus has been reached by the Taiwan Society of Cardiology and the Society of Nuclear Medicine of the Republic of China, to advocate for the application of 99mTc-PYP scintigraphy in the diagnosis of ATTR-CM. This article aims to highlight the recommendations on image acquisition, qualitative and quantitative assessments of cardiac 99mTc-PYP uptake, and diagnostic algorithms. We hope the implementation of these recommendations in Taiwan will facilitate the process and enhance the diagnostic rate of ATTR-CM.

A Review of Novel Agents and Clinical Considerations in Patients With ATTR Cardiac Amyloidosis

ABSTRACT

Transthyretin (ATTR) amyloidosis is a multisystem disease caused by organ deposition of amyloid fibrils derived from the misfolded transthyretin (TTR) protein. The purpose of this article is to provide an overview of current treatment regimens and summarize important considerations for each agent. A literature search was performed with the PubMed database for articles published through October 2020. Search criteria included therapies available on the market and investigational therapies used for ATTR amyloidosis treatment. Both prospective clinical trials and retrospective studies have been included in this review. Available therapies discussed in this review article are tafamidis, diflunisal, patisiran, and inotersen. Tafamidis is FDA approved for treatment of wild-type ATTR (ATTRwt) and hereditary ATTR (ATTRv) cardiomyopathy, and patisiran and inotersen are FDA approved for ATTRv polyneuropathy. Diflunisal does not have an FDA-labeled indication for amyloidosis but has been studied in ATTRv polyneuropathy and ATTRwt cardiomyopathy. Investigational therapies include a TTR stabilizer, AG10; 2 antifibril agents, PRX004 and doxycycline/tauroursodeoxycholic acid; and 2 gene silencers, vutrisiran and AKCEA-TTR-LRx; and clinical trials are ongoing. ATTR amyloidosis treatment selection is based on subtype and presence of cardiac or neurological manifestations. Additional considerations such as side effects, monitoring, and administration are outlined in this review.

Clinical approach to genetic testing in amyloid cardiomyopathy: from mechanism to effective therapies

PURPOSE OF REVIEW

To highlight the evolving understanding of genetic variants, utility of genetic testing, and the selection of novel therapies for cardiac amyloidosis.

RECENT FINDINGS

The last decade has seen considerable progress in cardiac amyloidosis recognition given the advancement in cardiac imaging techniques and widespread availability of genetic testing. A significant shift in the understanding of a genetic basis for amyloidosis has led to the development of disease-modifying therapeutic strategies that improve survival.

SUMMARY

The systemic amyloidoses are disorders caused by extracellular deposition of misfolded amyloid fibrils in various organs. Immunoglobulin light-chain or transthyretin amyloidosis are the most common types associated with cardiac manifestations. Genetic testing plays a central role in the identification of genotypes that are associated with different clinical phenotypes and influence prognosis. Given the emergence of effective therapies, a systematic approach to the diagnosis of cardiac amyloidosis, with the elucidation of genotype when indicated, is essential to select the appropriate treatment.

Wild type transthyretin cardiac amyloidosis in a young individual: A case report

RATIONALE

Senile systemic amyloidosis, a disease of elderly is caused by amyloid deposition of wild-type transthyretin. The symptoms often overlap with other heart diseases. Hence it is either misdiagnosed or considered as a normal aging process in majority of cases.

PATIENT CONCERNS

We present a young patient of wild-type transthyretin amyloidosis, contradicting its only senile presence. The 34-year-old man presented with dyspnoea on exertion. He was suffering from hypertension for consecutive 3 years.

DIAGNOSIS

Echocardiography demonstrated left ventricular hypertrophy with reduced global longitudinal strain and apical sparing. Congo red staining and immuno-histochemical staining of the abdominal fat biopsy confirmed transthyretin amyloid deposition. Genetic analysis revealed absence of any mutant variant/s of transthyretin gene, confirming wild-type transthyretin amyloidosis.

INTERVENTION

A combination of amlodipine 5 mg, telmisartan 40 mg, and chlorthalidone 12.5 mg once daily was given to control the blood pressure of the patient.

OUTCOME

Blood pressure was controlled but he continued to have exertional dyspnoea. The patient expired in December 2019.

LESSONS

A systematic diagnosis for wild type transthyretin amyloid cardiomyopathy (ATTR-CM) shall be considered in young cardiac patients suffering from cardiac distress with unknown etiology.

Through thick and thin: Diagnosis of transthyretin cardiac amyloidosis through non-invasive multimodality imaging

Cardiac amyloidosis is a severely underdiagnosed cause of heart failure with preserved ejection fraction. We report a case of highly probable transthyretin (ATTR) cardiac amyloidosis (ATTR-CA) diagnosed through the assistance of non-invasive multimodality imaging. An 81-year-old man presented with worsening dyspnoea, reduced effort tolerance and limb swelling. Examination and bedside investigations demonstrated congestive cardiac failure. On arrival, N-terminal-pro B-type natriuretic peptide was 2400 ng/L, and high-sensitivity troponin T was 78 mmol/L. Echocardiography showed severe left and right ventricular hypertrophy, and a Doppler study revealed diastolic dysfunction. Cardiac magnetic resonance imaging revealed on non-conventional dark blood sequence an abnormal inversion time for nulling myocardium suggestive of infiltrative disease, including amyloidosis. The patient was referred for nuclear-based studies involving technetium-99m pyrophosphate which demonstrated changes highly diagnostic of ATTR-CA. Early diagnosis of ATTR-CA remains paramount due to the increasing availability of disease-modifying therapies. Current guidelines recognise the role of multimodality imaging in confidently recognising the disease without the need for histological evidence in the appropriate context, providing an alternative means of diagnosis.

The State of the Heart Biopsy: A Clinical Review

Endomyocardial biopsy (EMB) is an invaluable and underused diagnostic tool for myocardial disease. The primary indications are surveillance of cardiac allograft rejection and the diagnosis of inflammatory and infiltrative cardiomyopathies. EMB is typically performed by sampling the right ventricular septum via the right internal jugular vein using fluoroscopic guidance. The diagnostic yield of EMB is improved by sampling both ventricles and with the use of guidance from imaging or electroanatomic mapping. The risk of major cardiac complications is operator dependent and < 1% in experienced centres. EMB is the gold standard and most common form of cardiac allograft rejection surveillance, whereas advanced cardiac imaging and donor-specific antibody quantification provide complementary information. Gene expression profiling is an alternative surveillance strategy to EMB for low-risk patients. EMB is recommended for myocarditis and can guide therapy for giant-cell myocarditis, necrotizing eosinophilic myocarditis, sarcoidosis, and immune checkpoint inhibitor myocarditis. There is growing interest in using EMB to guide therapy for viral myocarditis, although the uptake of this approach is limited to specialized centres. EMB has been replaced as a first-line test for infiltrative cardiomyopathy by nonbiopsy diagnostic techniques, but is still useful to clarify the diagnosis or disease subtype. The miniaturization of bioptomes and advances in laboratory techniques such as microarrays promises to improve the safety and yield of EMB. We review the contemporary use of EMB for cardiac allograft rejection, inflammatory cardiomyopathy, and infiltrative cardiomyopathy.

Dysautonomia: A Forgotten Condition - Part 1

Dysautonomia covers a range of clinical conditions with different characteristics and prognoses. They are classified as Reflex Syndromes, Postural Orthostatic Tachycardia Syndrome (POTS), Chronic Fatigue Syndrome, Neurogenic Orthostatic Hypotension (nOH) and Carotid Sinus Hypersensitivity Syndrome. Reflex (vasovagal) syndromes will not be discussed in this article. Reflex (vasovagal) syndromes are mostly benign and usually occur in patients without an intrinsic autonomic nervous system (ANS) or heart disease. Therefore, they are usually studied separately. Cardiovascular Autonomic Neuropathy (CAN) is the term most currently used to define dysautonomia with impairment of the sympathetic and/or parasympathetic cardiovascular autonomic nervous system. It can be idiopathic, such as multisystemic atrophy or pure autonomic failure, or secondary to systemic pathologies such as diabetes mellitus, neurodegenerative diseases, Parkinson's disease, dementia syndromes, chronic renal failure, amyloidosis and it may also occur in the elderly. The presence of Cardiovascular Autonomic Neuropathy (CAN) implies greater severity and worse prognosis in various clinical situations. Detection of Orthostatic Hypotension (OH) is a late sign and means greater severity in the context of dysautonomia, defined as Neurogenic Orthostatic Hypotension (nOH). It must be differentiated from hypotension due to hypovolemia or medications, called non-neurogenic orthostatic hypotension (nnOH). OH can result from benign causes, such as acute, chronic hypovolemia or use of various drugs. However, these drugs may only reveal subclinical pictures of Dysautonomia. All drugs of patients with dysautonomic conditions should be reevaluated. Precise diagnosis of CAN and the investigation of the involvement of other organs or systems is extremely important in the clinical suspicion of pandysautonomia. In diabetics, in addition to age and time of disease, other factors are associated with a higher incidence of CAN, such poor glycemic control, hypertension, dyslipidemia and obesity. Among diabetic patients, 38-44% can develop Dysautonomia, with prognostic implications and higher cardiovascular mortality. In the initial stages of DM, autonomic dysfunction involves the parasympathetic system, then the sympathetic system and, later on, it presents as orthostatic hypotension. Valsalva, Respiratory and Orthostatic tests (30:15) are the gold standard methods for the diagnosis of CAN. They can be associated with RR Variability tests in the time domain, and mainly in the frequency domain, to increase the sensitivity (protocol of the 7 tests). These tests can detect initial or subclinical abnormalities and assess severity and prognosis. The Tilt Test should not be the test of choice for investigating CAN at an early stage, as it detects cases at more advanced stages. Tilt response with a dysautonomic pattern (gradual drop in blood pressure without increasing heart rate) may suggest CAN. Treatment of patients at moderate to advanced stages of dysautonomia is quite complex and often refractory, requiring specialized and multidisciplinary evaluation. There is no cure for most types of Dysautonomia at a late stage. NOH patients can progress with supine hypertension in more than 50% of the cases, representing a major therapeutic challenge. The immediate risk and consequences of OH should take precedence over the later risks of supine hypertension and values greater than 160/90 mmHg are tolerable. Sleeping with the head elevated (20-30 cm), not getting up at night, taking short-acting antihypertensive drugs for more severe cases, such as losartan, captopril, clonidine or nitrate patches, may be necessary and effective in some cases. Preventive measures such as postural care; good hydration; higher salt intake; use of compression stockings and abdominal straps; portioned meals; supervised physical activity, mainly sitting, lying down or exercising in the water are important treatment steps. Various drugs can be used for symptomatic nOH, especially fludrocortisone, midodrine and droxidopa, the latter not available in Brazil. The risk of exacerbation or triggering supine hypertension should be considered. Chronic Fatigue Syndrome represents a form of Dysautonomia and has been renamed as a systemic disease of exercise intolerance, with new diagnostic criteria: 1 - Unexplained fatigue, leading to occupational disability for more than 6 months; 2 - Feeling ill after exercising; 3 - Non-restorative sleep; 4 - One of the following findings: cognitive impairment or orthostatic intolerance. Several pathologies today have evolved with chronic fatigue, being called chronic diseases associated with chronic fatigue. Postural orthostatic tachycardia syndrome (POTS), another form of presentation of dysautonomic syndromes, is characterized by sustained elevation of heart rate (HR) ≥30 bpm (≥40 bpm if <20 years) or HR ≥120 bpm, in the first 10 minutes in an orthostatic position or during the tilt test, without classical orthostatic hypotension associated. A slight decrease in blood pressure may occur. Symptoms appear or get worse in an orthostatic position, with dizziness, weakness, pre-syncope, palpitations, and other systemic symptoms being common.

Cardiac Amyloidosis Presenting as Biventricular Systolic Heart Failure

A previously healthy octogenarian presented with new onset heart failure symptoms. Comprehensive multimodality imaging including complete echocardiography with longitudinal strain analysis, cardiac magnetic resonance imaging (cMRI), nuclear medicine pyrophosphate (99-mcTcPYP) scan along with biomarker, monoclonal protein analysis, and fat pad biopsy confirmed diagnosis of transthyretin cardiac amyloidosis.

Updates in Cardiac Amyloidosis Diagnosis and Treatment

PURPOSE OF REVIEW

Cardiac amyloidosis is an underrecognized cause of heart failure. We review clinical clues to the diagnoses, a rational approach to testing, and current and emerging therapies.

RECENT FINDINGS

Advances in the diagnosis of amyloid cardiomyopathy include (1) use of ^99mtechnetium (^99mTc) bone-avid compounds which allow accurate noninvasive diagnosis of transthyretin cardiac amyloidosis (ATTR-CM) in the context of a negative monoclonal light chain screen; and (2) the use of serum and urine immunofixation electrophoresis with serum free light chains as an accurate first diagnostic step for light chain cardiac amyloidosis (AL-CM). Advances in treatment include tafamidis for ATTR-CM and immunologic therapies for AL-CM. With the advent of accurate noninvasive diagnostic modalities and effective therapies, early recognition of cardiac amyloidosis is paramount to implement a diagnostic algorithm and expeditiously institute effective therapies to minimize morbidity and mortality.

Cardiac amyloidosis-A review of current literature for the practicing physician

The amyloidoses are a family of diseases in which misfolded precursor proteins aggregate to form amyloid and deposit in body tissues. A very serious yet underrecognized form of this disease is cardiac amyloidosis, in which amyloid deposits into the extracellular space of the myocardium, resulting in thickening and stiffening of ventricular walls with resultant heart failure and conductive dysfunction. This review provides a discussion of the pathogenesis and clinical presentation of cardiac amyloidosis subtypes, as well as an up-to-date approach to diagnosis and treatment. Significant progress has been made in recent years regarding diagnosis and treatment of this condition, but prognosis remains heavily reliant on early detection of the disease. Two types of precursor protein are responsible for most cardiac amyloidosis cases: transthyretin amyloid, and immunoglobulin-derived light chain amyloid. An early diagnosis of cardiac amyloidosis can allow for novel treatment modalities to be initiated with the potential to improve prognosis.

The Importance of Multimodality Imaging in the Diagnosis and Management of Patients with Infiltrative Cardiomyopathies: An Update

Infiltrative cardiomyopathies (ICMs) comprise a broad spectrum of inherited and acquired conditions (mainly amyloidosis, sarcoidosis, and hemochromatosis), where the progressive buildup of abnormal substances within the myocardium results in left ventricular hypertrophy and manifests as restrictive physiology. Noninvasive multimodality imaging has gradually eliminated endomyocardial biopsy from the diagnostic workup of infiltrative cardiac deposition diseases. However, even with modern imaging techniques’ widespread availability, these pathologies persist in being largely under- or misdiagnosed. Considering the advent of novel, revolutionary pharmacotherapies for cardiac amyloidosis, the archetypal example of ICM, a standardized diagnostic approach is warranted. Therefore, this review aims to emphasize the importance of contemporary cardiac imaging in identifying specific ICM and improving outcomes via the prompt initiation of a targeted treatment.

Diagnosis and treatment of cardiac amyloidosis: position statement of the German Cardiac Society (DGK)

Systemic forms of amyloidosis affecting the heart are mostly light-chain (AL) and transthyretin (ATTR) amyloidoses. The latter is caused by deposition of misfolded transthyretin, either in wild-type (ATTRwt) or mutant (ATTRv) conformation. For diagnostics, specific serum biomarkers and modern non-invasive imaging techniques, such as cardiovascular magnetic resonance imaging (CMR) and scintigraphic methods, are available today. These imaging techniques do not only complement conventional echocardiography, but also allow for accurate assessment of the extent of cardiac involvement, in addition to diagnosing cardiac amyloidosis. Endomyocardial biopsy still plays a major role in the histopathological diagnosis and subtyping of cardiac amyloidosis. The main objective of the diagnostic algorithm outlined in this position statement is to detect cardiac amyloidosis as reliably and early as possible, to accurately determine its extent, and to reliably identify the underlying subtype of amyloidosis, thereby enabling subsequent targeted treatment.

Nuclear Imaging for Cardiac Amyloidosis: Bone Scan, SPECT/CT, and Amyloid-Targeting PET

Cardiac amyloidosis (CA) is a type of systemic amyloidosis, in which abnormal amyloid fibril is deposited in extracellular space of myocardium. Most common subtypes of CA are amyloidosis of immunoglobulin light chain (AL) and amyloidosis of transthyretin (ATTR). With increase in incidence of CA and development of new drugs, the needs of early and accurate diagnosis of CA are increasing. In CA, bone scan and SPECT/CT have long been used for diagnosis. Currently, bone scan is included in almost all practice guidelines as one of key diagnostic examinations for ATTR CA. In some specific scenarios, bone scan can be used as even a substitute for endomyocardial biopsy. Recently, amyloid-targeting PET that is used for Alzheimer dementia has also been attempted as an imaging method for CA. Although the study results are still insufficient, amyloid-targeting has shown promising potential as an imaging method for CA, particularly in AL. Here, imaging method and clinical application and implication of bone scan, SPECT/CT, and amyloid-targeting PET/CT in CA are reviewed.

Diagnosis of amyloid beyond Congo red

PURPOSE OF REVIEW

Amyloidoses are a group of rare and heterogeneous diseases in which abnormally folded proteins deposit in tissues and lead to organ damage. A brief review of advances in the diagnosis of extracerebral systemic amyloidoses in the context of recent advances in their clinical management is provided.

RECENT FINDINGS

Although steady progress in the treatment of AL and AA has evolved over many years, significant advances in the treatment of ATTR, transthyretin-derived amyloidosis, have been achieved only recently. This coincides with the emergence of nontissue diagnosis of cardiac ATTR in both the hereditary and wild-type settings. The latter is emerging as possibly the most prevalent type of systemic amyloidosis.Available treatments are amyloid protein type dependent and, hence, following amyloid detection, amyloid protein typing is necessary. Although mass spectrometry has emerged as the preferred method of amyloid typing, careful application of immune methods is still clinically useful but caution and experience, as well as awareness of the limitations of each method, are necessary in their interpretation.

SUMMARY

Despite significant advances in the treatment of the systemic amyloidoses, outcomes remain poor, primarily due to delays in diagnosis. Precise diagnosis of the amyloid protein type is critical for treatment selection.

Building a Heart Failure Clinic: A Practical Guide from the Heart Failure Society of America

Heart failure (HF) remains a leading cause of mortality and morbidity and a primary driver of health care resource use in the United States. As such, there continues to be much interest in the development and refinement of HF clinics that manage patients with HF in a guideline-directed, technology-enabled, and coordinated approach. Optimization of resource use and maintenance of collaboration with other providers are also important themes when considering implementation of HF clinics. Through this document, the Heart Failure Society of America aims to provide a contemporary, practical guide to creating and sustaining a HF clinic. The guide discusses (1) patient care considerations for delivering guideline-directed and patient-centered care, and (2) operational considerations including development of a HF clinic business plan, setting goals, leadership support, triggers for patient referral and patient follow-up, patient population served, optimal clinic staffing models, relationships with subspecialists, and continuous quality improvement. This document was developed to empower providers and clinicians who wish to build and sustain community-based, successful HF clinics.

Ventricular Arrhythmias in Cardiac Amyloidosis: A Review of Current Literature

Cardiac Amyloidosis is an infiltrative cardiomyopathy which occurs secondary to deposition of mis-folded protein in the myocardium, with the two most common subtypes being AL amyloidosis and TTR amyloidosis. The pathogenesis of the disease is multifaceted and involves a variety of mechanisms including an inflammatory response cascade, oxidative stress and subsequent separation of myocyte fibrils. Cardiac Amyloidosis frequently results in congestive cardiac failure and arrhythmias, from a disruption in cardiac substrate with subsequent electro-mechanical remodelling. Disease progression is usually demonstrated by development of progressive pump failure, which may be seen with a high arrhythmic burden, usually portending a poor prognosis. There is a paucity of literature on the clinical implications of ventricular arrhythmias in the context of cardiac amyloidosis. The important diagnostic investigations for these patients include transthoracic echocardiography, cardiac magnetic resonance imaging and an electrophysiology study. Whilst there are no robust management guidelines, studies have indicated benefits from contemporary pharmacological therapy and case-by-case catheter ablation. There are novel directed therapies available for TTR amyloidosis that have shown to improve overall survival. The role of ICD therapy in cardiac amyloidosis is controversial, with benefits seen predominantly in early phases of the disease process. The only definitive surgical therapy includes heart transplantation, but is largely indicated for progressive decompensated heart failure (Figure 1). Further large-scale studies are required to better outline management paradigms for treating ventricular arrhythmias in cardiac amyloidosis.

Epidemiology of the inherited cardiomyopathies

In the absence of contemporary, population-based epidemiological studies, estimates of the incidence and prevalence of the inherited cardiomyopathies have been derived from screening studies, most often of young adult populations, to assess cardiovascular risk or to detect the presence of disease in athletes or military recruits. The global estimates for hypertrophic cardiomyopathy (1/500 individuals), dilated cardiomyopathy (1/250) and arrhythmogenic right ventricular cardiomyopathy (1/5,000) are probably conservative given that only individuals who fulfil diagnostic criteria would have been included. This caveat is highly relevant because a substantial minority or even a majority of individuals who carry disease-causing genetic variants and are at risk of disease complications have incomplete and/or late-onset disease expression. The genetic literature on cardiomyopathy, which is often focused on the identification of genetic variants, has been biased in favour of pedigrees with higher penetrance. In clinical practice, an abnormal electrocardiogram with normal or non-diagnostic imaging results is a common finding for the sarcomere variants that cause hypertrophic cardiomyopathy, the titin and sarcomere variants that cause dilated cardiomyopathy and the desmosomal variants that cause either arrhythmogenic right ventricular cardiomyopathy or dilated cardiomyopathy. Therefore, defining the genetic epidemiology is also challenging given the overlapping phenotypes, incomplete and age-related expression, and highly variable penetrance even within individual families carrying the same genetic variant.

Sex Differences in the Phenotype of Transthyretin Cardiac Amyloidosis Due to Val122Ile Mutation: Insights from Noninvasive Pressure-Volume Analysis

BACKGROUND

Transthyretin cardiac amyloidosis (ATTR-CA) is an under-recognized cause of heart failure with preserved ejection fraction. In the United States, the valine-to-isoleucine substitution (Val122Ile) is the most common inherited variant. Data on sex differences in presentation and outcomes of Val122Ile associated ATTR-CA are lacking.

METHODS AND RESULTS

In a retrospective, single-center study of 73 patients diagnosed with Val122Ile associated ATTR-CA between 2001 and 2018, sex differences in clinical and echocardiographic data at the time of diagnosis were evaluated. Pressure-volume analysis using noninvasive single beat techniques was used to compare chamber performance. Compared with men (n = 46), women (n = 27) were significantly older at diagnosis, 76 years vs 69 years; P < .001. The end-systolic pressure-volume relationship, 5.1 mm Hg*m²/mL vs 4.3 mm Hg*m²/mL; P = .27, arterial elastance, 5.5 mm Hg*m²/mL vs 5.7 mm Hg*m²/mL; P = .62, and left ventricular capacitance were similar between sexes as was pressure-volume areas indexed to a left ventricular end-diastolic pressure of 30 mm Hg, a measure of overall pump function. The 3-year mortality rates were also similar, 34% vs 43%; P = .64.

CONCLUSIONS

Despite being significantly older at time of diagnosis with Val122Ile associated ATTR-CA, women have similar overall cardiac chamber function and rates of mortality to men, suggesting a less aggressive disease trajectory. These findings should be confirmed with longitudinal studies.

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.