Cardiac amyloidosis: An update on pathophysiology, diagnosis, and treatment

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.

Percutaneous Mitral Valve Repair in Cardiac Amyloidosis and Severe Mitral Regurgitation

Amyloidosis is an infiltrative disease with severe impact on the cardiac anatomy resulting in structural changes¹. Mitral valve insult from the infiltrative process, although rare, has been known to cause severe mitral regurgitation⁴. Due to underlying comorbidities these patients may not be surgical candidates.^17,18,19,20 The role of percutaneous mitral valve repair in cardiac amyloidosis has been described in a few prior cases.^4,15 We review the epidemiology, diagnosis, and treatment of cardiac amyloidosis. We also highlight prior cases described in the literature of cardiac amyloidosis and severe mitral regurgitation, while discussing the role of percutaneous mitral valve repair in these patients.

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.

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.

A special case of hypertrophic cardiomyopathy with a differential diagnosis of isolated cardiac amyloidosis or junctophilin type 2 associated cardiomyopathy

Differential diagnosis between hypertrophic cardiomyopathy (HCM) and cardiac amyloidosis (CA) is mandatory since the prognosis is very different, but not always possible as both diseases present with increased myocardial thickness and mass. Despite better knowledge of the pathophysiology of both HCM and CA, and new developments in diagnosis, many patients with cardiac involvement in systemic amyloidosis are still only diagnosed in an advanced stage. Improvements in non-invasive diagnostic methods such as ultrasound techniques and cardiac magnetic resonance imaging will eventually obviate the need for invasive studies in order to prove amyloid cardiomyopathy. Nevertheless, today, an endomyocardial biopsy still remains the golden standard. We present an 86-year-old man, diagnosed with hypertrophic cardiomyopathy, in whom echocardiography and cardiac magnetic resonance imaging strongly suggested amyloidosis to be the underlying cause. Interestingly, a new variant of the junctophilin 2 (JPH2) gene, related to hypertrophic cardiomyopathies, was found in our patient.

Recent advances in the diagnosis and management of amyloid cardiomyopathy

Amyloidosis is a disorder characterized by misfolded precursor proteins that form depositions of fibrillar aggregates with an abnormal cross-beta-sheet conformation, known as amyloid, in the extracellular space of several tissues. Although there are more than 30 known amyloidogenic proteins, both hereditary and non-hereditary, cardiac amyloidosis (CA) typically arises from either misfolded transthyretin (ATTR amyloidosis) or immunoglobulin light-chain aggregation (AL amyloidosis). Its prevalence is more common than previously thought, especially among patients with heart failure and preserved ejection fraction (HFpEF) and aortic stenosis. If there is a clinical suspicion of CA, focused echocardiography, laboratory screening for the presence of a monoclonal protein (serum and urinary electrophoresis with immunofixation and serum free light-chain ratio), and cardiac scintigraphy with 99mtechnetium-labeled bone-tracers are sensitive and specific initial diagnostic tests. In some cases, more advanced/invasive techniques are necessary and, in the last several years, treatment options for both AL CA and ATTR CA have rapidly expanded. It is important to note that the aims of therapy are different. Systemic AL amyloidosis requires treatment targeted against the abnormal plasma cell clone, whereas therapy for ATTR CA must be targeted to the production and stabilization of the TTR molecule. It is likely that a multistep treatment approach will be optimal for both AL CA and ATTR CA. Additionally, treatment of CA includes the management of restrictive cardiomyopathy with preserved or reduced ejection fraction in addition to treating the amyloid deposition. Future studies are necessary to define optimal management strategies for AL CA and ATTR CA and confirm cardiac response to therapy.

Influence of Ventricular Wringing on the Preservation of Left Ventricular Ejection Fraction in Cardiac Amyloidosis

BACKGROUND

The purpose of this work was to determine the influence of myocardial wringing on ventricular function in patients with cardiac amyloidosis (CA).

METHODS

Fifteen healthy volunteers (group 1) and 34 patients with CA (17 with left ventricular ejection fractions [LVEFs] ≥ 53% [group 2] and 17 with LVEFs < 53% [group 3]) were evaluated using two-dimensional speckle-tracking echocardiography. A control group of mass-matched patients (n = 20) with left ventricular (LV) hypertrophy and LVEFs ≥ 53% was also included. Longitudinal strain (LS), circumferential strain, and LV twist and torsion were calculated. Deformation index (DefI), a new parameter of wringing, calculated as twist/LS, that takes into account actions that occur simultaneously during LV systole (i.e., longitudinal shortening and twist), was evaluated. Torsional and wringing parameters were calculated according to LVEF.

RESULTS

Lower global values of LS and circumferential strain were observed among patients with CA (LS: group 1, -20.6 ± 2.5%; group 2, -11.6 ± 4.1%; group 3, -9.0 ± 3.1%; circumferential strain: group 1, -22.7 ± 4.9%; group 2, -14.4 ± 8.0%; group 3, -13.6 ± 3.8%; P < .001 for both). Torsion did not vary between group 2 and group 1 (2.5 ± 1.1°/cm vs 2.7 ± 0.8°/cm, P = NS). In contrast, DefI was greater in group 2 than in group 1 (-1.8 ± 0.8°/% vs -1.0 ± 0.3°/%, P < .01). Torsion and DefI were lower in group 3 (1.2 ± 0.7°/cm and -1.1 ± 0.6°/%, respectively, P < .001 for both) than in group 2. DefI was similar in patients with LV hypertrophy (-1.7 ± 0.6°/%, P = NS) and group 2.

CONCLUSIONS

In patients with CA, preservation of LVEF depends on greater ventricular wringing. DefI, a parameter that integrates the twist and the simultaneous longitudinal shortening of the left ventricle, is a more accurate indicator of the efficacy of this mechanism.

Superb microvascular imaging for detecting carpal tunnel syndrome compared with power Doppler ultrasonography: A protocol for systematic review and meta-analysis

BACKGROUND

Sonography enhances diagnostic accuracy by the detection of the epineural or intraneuronal blood flow.[1-4] Power Doppler ultrasonography (PDUS) in carpal tunnel syndrome (CTS) has been previously studied and shown to be valid and reliable for grading the intraneural flow.[3,4] However, superb microvascular imaging (SMI) represents a new era in diagnostic sonography, and this new technology enables accurate visualization of vascular structures with intensive clutter suppression to provide flow signals for large to small vessels, and it presents these data at high frame rates.[5-7] Studies suggested that SMI is more sensitive in demonstrating blood flow in the diagnosis of CTS compared with PDUS.[7] In order to gain clarity, a meta-analysis to systematically review and synthesize relevant data on the evaluating intraneural blood flow of the median nerve (MN) using SMI and PDUS was undertaken.

METHODS

We will search PubMed, Web of Science, Cochrane Library, and Chinese biomedical databases from their inceptions to the December 31, 2020, without language restrictions. Two authors will independently carry out searching literature records, scanning titles and abstracts, full texts, collecting data, and assessing risk of bias. Review Manager 5.2 and Stata 14.0 software will be used for data analysis.

RESULTS

This systematic review will investigate whether superb microvascular imaging is more sensitive to display the blood flow in the MN with CTS than PDUS.

CONCLUSION

Its findings will provide strong evidence for the feasibility of superb microvascular imaging on the detection of the neovascularization of the MN with CTS.

SYSTEMATIC REVIEW REGISTRATION

INPLASY202110018.

Cardiac Amyloidosis Therapy: A Systematic Review

Heart involvement in Cardiac Amyloidosis (CA) results in a worsening of the prognosis in almost all patients with both light-chain (AL) and transthyretin amyloidosis (ATTR). The mainstream CA is a restrictive cardiomyopathy with hypertrophic phenotype at cardiac imaging that clinically leads to heart failure with preserved ejection fraction (HFpEF). An early diagnosis is essential to reduce cardiac damage and to improve the prognosis. Many therapies are available, but most of them have late benefits to cardiac function; for this reason, novel therapies are going to come soon.

Practical recommendations for the diagnosis and management of transthyretin cardiac amyloidosis

Cardiac amyloidosis (CA) is an infiltrative restrictive cardiomyopathy caused by accumulation in the heart interstitium of amyloid fibrils formed by misfolded proteins. Most common CA types are light chain amyloidosis (AL) caused by monoclonal immunoglobulin light chains and transthyretin amyloidosis (ATTR) caused by either mutated or wild-type transthyretin aggregates. Previously considered a rare disease, CA is increasingly recognized among patients who may be misdiagnosed as undifferentiated heart failure with preserved ejection fraction (HFPEF), paradoxical low-flow/low-gradient aortic stenosis, or otherwise unexplained left ventricular hypertrophy. Progress in diagnosis has been due to the refinement of cardiac echocardiographic techniques (speckle tracking imaging) and magnetic resonance (T1 mapping) and mostly due to the advent of bone scintigraphy that has enabled noninvasive diagnosis of ATTR, limiting the need for endomyocardial biopsy. Importantly, proper management of CA starts from early recognition of suspected cases among high prevalence populations, followed by advanced diagnostic evaluation to confirm diagnosis and typing, preferentially in experienced amyloidosis centers. Differentiating ATTR from other types of amyloidosis, especially AL, is critical. Emerging targeted ATTR therapies offer the potential to improve outcomes of these patients previously treated only palliatively.

Expanding Indications for Liver Transplant: Tumor and Patient Factors

During the past few decades, liver transplant has developed from a high-mortality procedure to an almost routine procedure with good survival outcomes. The development of living donor liver transplant has increased the availability of liver grafts, and the scope of indications for liver transplant has been expanding ever since. The aim of this review is to provide an overview of such an expansion of scope. Various criteria have been proposed to expand the eligibility of patients with hepatocellular carcinoma exceeding the Milan criteria for liver transplant. Furthermore, liver transplant is increasingly performed as a treatment modality for cholangiocarcinoma, neuroendocrine liver metastasis and colorectal liver metastasis. The number of elderly patients receiving liver transplant is on the rise. Combined organ transplantation has also been adopted to treat patients with multiple organ failure. Going forward, further development of preoperative noninvasive predictors in tumor, patient and even donor factors is needed to identify patients at risk of poor outcomes and hence optimize patient management.

Musculoskeletal pathology as an early warning sign of systemic amyloidosis: a systematic review of amyloid deposition and orthopedic surgery

BACKGROUND

Transthyretin and immunoglobulin light-chain amyloidoses cause amyloid deposition throughout various organ systems. Recent evidence suggests that soft tissue amyloid deposits may lead to orthopedic conditions before cardiac manifestations occur. Pharmacologic treatments reduce further amyloid deposits in these patients. Thus, early diagnosis improves long term survival.

QUESTIONS/PURPOSES

The primary purpose of this systematic review was to characterize the association between amyloid deposition and musculoskeletal pathology in patients with common orthopedic conditions. A secondary purpose was to determine the relationship between amyloid positive biopsy in musculoskeletal tissue and the eventual diagnosis of systemic amyloidosis.

METHODS

We performed a systematic review using PRISMA guidelines. Inclusion criteria were level I-IV evidence articles that analyzed light-chain or transthyretin amyloid deposits in common orthopedic surgeries. Study methodological quality, risk of bias, and recommendation strength were assessed using MINORS, ROBINS-I, and SORT.

RESULTS

This systematic review included 24 studies for final analysis (3606 subjects). Amyloid deposition was reported in five musculoskeletal pathologies, including carpal tunnel syndrome (transverse carpal ligament and flexor tenosynovium), hip and knee osteoarthritis (synovium and articular cartilage), lumbar spinal stenosis (ligamentum flavum), and rotator cuff tears (tendon). A majority of studies reported a mean age greater than 70 for patients with TTR or AL positive amyloid.

CONCLUSIONS

This systematic review has shown the presence of amyloid deposition detected at the time of common orthopedic surgeries, especially in patients ≥70 years old. Subtyping of the amyloid has been shown to enable diagnosis of systemic light-chain or transthyretin amyloidosis prior to cardiac manifestations.

LEVEL OF EVIDENCE

Level IV.

[Cardiac amyloidosis]

Different types of amyloid deposits involve the heart. Transthyretin and light chain amyloidosis are the most frequent. Diagnostic performance, typing and treatments have improved in the last decade, and prognosis of cardiac amyloidosis is now significantly better thanks to targeted therapies. In this article, we will describe the clinical manifestations of cardiac amyloidosis, the diagnostic approach and detail the characteristics and specific treatments of the most frequent types of cardiac amyloidosis. We will focus on the histopathological aspects, especially on the importance of amyloid typing.

Neurological complications of cardiomyopathies

There is a multifaceted relationship between the cardiomyopathies and a wide spectrum of neurological disorders. Severe acute neurological events, such as a status epilepticus and aneurysmal subarachnoid hemorrhage, may result in an acute cardiomyopathy the likes of Takotsubo cardiomyopathy. Conversely, the cardiomyopathies may result in a wide array of neurological disorders. Diagnosis of a cardiomyopathy may have already been established at the time of the index neurological event, or the neurological event may have prompted subsequent cardiac investigations, which ultimately lead to the diagnosis of a cardiomyopathy. The cardiomyopathies belong to one of the many phenotypes of complex genetic diseases or syndromes, which may also involve the central or peripheral nervous systems. A number of exogenous agents or risk factors such as diphtheria, alcohol, and several viruses may result in secondary cardiomyopathies accompanied by several neurological manifestations. A variety of neuromuscular disorders, such as myotonic dystrophy or amyloidosis, may demonstrate cardiac involvement during their clinical course. Furthermore, a number of genetic cardiomyopathies phenotypically incorporate during their clinical evolution, a gamut of neurological manifestations, usually neuromuscular in nature. Likewise, neurological complications may be the result of diagnostic procedures or medications for the cardiomyopathies and vice versa. Neurological manifestations of the cardiomyopathies are broad and include, among others, transient ischemic attacks, ischemic strokes, intracranial hemorrhages, syncope, muscle weakness and atrophy, myotonia, cramps, ataxia, seizures, intellectual developmental disorder, cognitive impairment, dementia, oculomotor palsies, deafness, retinal involvement, and headaches.

How to Identify Transthyretin Cardiac Amyloidosis at an Early Stage

Cardiac involvement of systemic amyloidosis is preferentially observed in patients with amyloid light chain amyloidosis or transthyretin amyloidosis (ATTR). Owing to the development of diagnostic modalities and changes in recognition by physicians, transthyretin cardiac amyloidosis (ATTR-CA) is now understood to be a more common cause of heart failure than previously thought. Recent progress in disease-modifying therapeutic interventions, such as transthyretin stabilizers, has resulted in ATTR-CA changing from an incurable disease to a curable disease. These interventions are particularly effective in patients with mild symptoms of heart failure, thus indicating that early detection and a precise diagnosis are important for improving the prognosis. In this review article, we summarize the recent reports of early screening of ATTR-CA and describe some important points regarding the making of a precise diagnosis, especially focusing on histological evaluations.

Diagnostic and prognostic value of cardiac imaging in amyloidosis

Amyloidosis is an infiltrative disease caused by extracellular protein deposition that has accumulated a lot of scientific production in recent years. Different types of amyloidosis can affect the heart. Transthyretin amyloidosis and light chain amyloidosis are the two most common types of cardiac amyloidosis. These entities have a poor prognosis, so accurate diagnostic techniques are imperative for determining an early therapeutic approach. Recent advances in cardiac imaging and diagnostic strategies show that these tools are safe and can avoid the use of invasive diagnostic techniques to histological confirmation, such as endomyocardial biopsy. We performed a review on the diagnostic and prognostic implications of different cardiac imaging techniques in cardiac amyloidosis. We mainly focus on reviewing echocardiography, cardiac magnetic resonance, computed tomography and nuclear imaging techniques and the different safety measurements that can be done with each of them.

Can myocardial work indices contribute to the exploration of patients with cardiac amyloidosis?

BACKGROUND

Cardiac amyloidosis (CA) is a life-threatening restrictive cardiomyopathy. Identifying patients with a poor prognosis is essential to ensure appropriate care. The aim of this study was to compare myocardial work (MW) indices with standard echocardiographic parameters in predicting mortality among patients with CA.

METHODS

Clinical, biological and transthoracic echocardiographic parameters were retrospectively compared among 118 patients with CA. Global work index (GWI) was calculated as the area of left ventricular pressure-strain loop. Global work efficiency (GWE) was defined as percentage ratio of constructive work to sum of constructive and wasted works. Sixty-one (52%) patients performed a cardiopulmonary exercise.

RESULTS

GWI, GWE, global longitudinal strain (GLS), left ventricular ejection fraction (LVEF) and myocardial contraction fraction (MCF) were correlated with N-terminal prohormone brain natriuretic peptide (R=-0.518, R=-0.383, R=-0.553, R=-0.382 and R=-0.336, respectively; p<0.001). GWI and GLS were correlated with peak oxygen consumption (R=0.359 and R=0.313, respectively; p<0.05). Twenty-eight (24%) patients died during a median follow-up of 11 (4-19) months. The best cut-off values to predict all-cause mortality for GWI, GWE, GLS, LVEF and MCF were 937 mm Hg/%, 89%, 10%, 52% and 15%, respectively. The area under the receiver operator characteristic curve of GWE, GLS, GWI, LVEF and MCF were 0.689, 0.631, 0.626, 0.511 and 0.504, respectively.

CONCLUSION

In CA population, MW indices are well correlated with known prognosis markers and are better than LVEF and MCF in predicting mortality. However, MW does not perform better than GLS.

Amyloidosis and cardiovascular diseases: A clinical insight

Systemic amyloidosis is caused by the deposition of amyloid proteins in varying organ systems throughout the body, leading to dysfunction within those systems. The development of cardiac amyloidosis is one of the main indicators of poor prognosis in patients. Cardiac amyloidosis is most commonly caused by the immunoglobulin light chain amyloidosis and the transthyretin amyloidosis. Both have poor prognoses when associated with cardiac amyloidosis; however, the patients with the former subtype fair far worse than those with the latter. Despite amyloidosis having a history of being underdiagnosed, recent epidemiological data indicate that the rate of diagnosis has increased, which has coincided with improved in-patient median survival rates. It is of great importance that patients are diagnosed with the correct subtype as the main treatment strategy is to treat the underlying cause of amyloidosis. If a misdiagnosis is made, patients can receive treatment that might be ineffective or even harmful. A great progress has been made in pharmacological treatments for treating the underlying causes; however, many of the proposed treatments still need more evidence to support their use.

DISCOVERY: prevalence of transthyretin (TTR) mutations in a US-centric patient population suspected of having cardiac amyloidosis

BACKGROUND

Hereditary transthyretin-mediated amyloidosis (hATTR amyloidosis) is a multisystem disease that presents with polyneuropathy and/or cardiomyopathy.

METHODS

DISCOVERY, a multicenter screening study, enrolled patients with clinically suspected cardiac amyloidosis to determine the frequency of transthyretin (TTR) mutations and assess disease characteristics.

RESULTS

Of 1007 patients, the majority were from the US (84%), Black/African American (56%), male (63%), and with a mean (standard deviation) age of 65 (13) years. Among 1001 patients with genotyping results, 74 (7%) had a pathogenic TTR mutation (71/836 [8%] from the US). Val122Ile was the most common mutation, found in 11% of Black/African American patients overall; Black/African American ethnicity was an independent predictor of having a pathogenic TTR mutation. Additional independent predictors of such mutations in the total population and Black/African American group were interventricular septum thickness, low electrocardiogram voltage, and age.

CONCLUSIONS

Pathogenic TTR mutations occurred in 8% of US patients with suspected cardiac amyloidosis. Most mutations were Val122Ile, almost exclusively found in Black/African American patients. Disease often remains undetected until advanced and difficult to treat, therefore, clinicians should assess at-risk patients for hATTR amyloidosis as early as possible.

Diagnosis and treatment of cardiac amyloidosis: an interdisciplinary consensus statement

The prevalence and significance of cardiac amyloidosis have been considerably underestimated in the past; however, the number of patients diagnosed with cardiac amyloidosis has increased significantly recently due to growing awareness of the disease, improved diagnostic capabilities and demographic trends. Specific therapies that improve patient prognosis have become available for certain types of cardiac amyloidosis. Thus, the earliest possible referral of patients with suspicion of cardiac amyloidosis to an experienced center is crucial to ensure rapid diagnosis, early initiation of treatment, and structured patient care. This requires intensive collaboration across several disciplines, and between resident physicians and specialized centers. The aim of this consensus statement is to provide guidance for the rapid and efficient diagnosis and treatment of light-chain amyloidosis and transthyretin amyloidosis, which are the most common forms of cardiac amyloidosis.

Role of Echocardiography in the Diagnosis of Light Chain Amyloidosis: A Case Report and Review of Literature

Amyloid light-chain (AL) amyloidosis is a rare disease with a broad clinical presentation that depends on the affected organ. Cardiac amyloidosis, a rare entity, can present as an isolated form of AL amyloidosis. This isolated form is considered a challenging diagnosis due to its broad nonspecific clinical presentation. In this article, we report a case of an adult male who presented with shortness of breath and was found to have many specific features of cardiac amyloidosis on echocardiography. In absence of other organ involvement, the results of the echocardiography directed us toward the diagnosis of AL cardiac amyloidosis. In addition, we highlight the role of echocardiography in the diagnosis of cardiac amyloidosis.

Role of Nuclear Imaging in Cardiac Amyloidosis Management: Clinical Evidence and Review of Literature

Cardiac amyloidosis (CA) is an infiltrative disease characterized by the extracellular deposition of fibrils, amyloid, in the heart. The vast majority of patients with CA has one of two types between transthyretin amyloid (ATTR) and immunoglobulin light chain associated amyloid (AL), that have different prognosis and therapeutic options. CA is often underdiagnosed. The histological analysis of endomyocardial tissue is the gold standard for the diagnosis, although it has its limitations due to its invasive nature. Nuclear medicine now plays a key role in the early and accurate diagnosis of this disease, and in the ability to distinguish between the two forms. Recent several studies support the potential advantage of bone-seeking radionuclides as a screening technique for the most common types of amyloidosis, in particular ATTR form. This review presents noninvasive modalities to diagnose CA and focuses on the radionuclide imaging techniques (bone-seeking agents scintigraphy, cardiac sympathetic innervation and positron emission tomography studies) available to visualize myocardial amyloid involvement. Furthermore, we report the case of an 83-year old male with a history of prostate cancer, carcinoma of the cecum and kidney cancer, submitted to bone scan to detect bone metastasis, that revealed a myocardial uptake of 99mTC-HMPD suggestive of ATTR CA. An accurate and early diagnosis of CA able to distinguish beyween AL and ATTR CA combined to the improving therapies could improve the survival of patients with this disease.

Severe Aortic Stenosis and ATTRwt Amyloidosis - Beware in the Aging: A Case Report and Review of the Literature

Degenerative aortic valve (AV) disease is the most frequent valvular heart disease slowly progressing to severe aortic stenosis (AS) which usually requires aortic valve replacement. Another frequent condition, especially among elderly people, is cardiac amyloidosis (CA), particularly the wild-type transthyretin cardiac amyloidosis (ATTRwt). Since both of these diseases are considered a marker of ageing, there is a significant proportion of elderly patients who associate both severe AS and CA. Recent studies reported a high prevalence of both severe AS and CA (AS-CA) in elderly patients referred for TAVR of 13–16%, carrying a worse prognosis. The present case illustrates the diagnostic algorithm and the management of ATTRwt CA in an elderly patient with severe paradoxical low-flow low-gradient AS, accompanied by a review of the current literature about the red flags which help identifying CA in patients with severe AS, as well as the prognosis and management of these disease association.

Tc-99m-pyrophosphate scintigraphy for the diagnosis of ATTR cardiac amyloidosis: Comparison of quantitative and semi-quantitative approaches

BACKGROUND

ATTR cardiac amyloidosis (CA) can be diagnosed with Tc-99m-PYP scintigraphy. There are two recommended interpretative approaches: the quantitative heart-to-contralateral lung ratio (H/CL) at 1 hour and the semi-quantitative visual system at 3 hours. This study's aim was to compare both approaches and to apply the semi-quantitative method at 1 hour.

METHODS

Tc-99m-PYP scans of 122 consecutive subjects were reviewed using both approaches. On 1 hour planar images, regions of interest were drawn over the heart and contralateral chest to determine H/CL. Myocardial uptake was graded on 1 and 3 hour SPECT images according to the semi-quantitative method. Concordance was examined using kappa statistics.

RESULTS

31, 10, and 81 studies were positive, negative, and equivocal, respectively, for ATTR-CA using the H/CL approach. Using the grading system, 35, 77, and 10 scans were positive, negative, and equivocal, respectively. The quantitative approach led to a significantly higher proportion of equivocal studies compared to the semi-quantitative approach (P < .0001). These approaches yielded discordant results in 2 subjects; biopsy results were concordant with SPECT grade. 1 and 3 hour SPECT grades provided concordant result in 99% of cases.

CONCLUSIONS

The H/CL approach resulted in a high proportion of equivocal studies. Using SPECT imaging, the semi-quantitative approach minimized this proportion and showed high concordance at 1 and 3 hours.

Imaging cardiac innervation in hereditary transthyretin (ATTRm) amyloidosis: A marker for neuropathy or cardiomyopathy in case of heart failure?

BACKGROUND

Nuclear imaging modalities using 123Iodine-metaiodobenzylguanidine (123I-MIBG) and bone seeking tracers identify early cardiac involvement in ATTRm amyloidosis patients. However, little is known whether results from 123I-MIBG scintigraphy actually correlate to markers for either cardiac autonomic neuropathy or cardiomyopathy.

METHODS

All TTR mutation carriers and ATTRm patients who underwent both 123I-MIBG and 99mTechnetium-hydroxymethylene diphosphonate (99mTc-HDP) scintigraphy were included. Cardiomyopathy was defined as NT-proBNP > 365 ng/L, and cardiac autonomic neuropathy as abnormal cardiovascular reflexes at autonomic function tests. Late 123I-MIBG heart-to-mediastinum ratio (HMR) < 2.0 or wash-out > 20%, and any cardiac 99mTc-HDP uptake were considered as abnormal.

RESULTS

39 patients (13 carriers and 26 ATTRm patients) were included in this study. Patients with cardiomyopathy, with or without cardiac autonomic neuropathy, had lower late HMR than similar patients without cardiomyopathy [median 1.1 (range 1.0-1.5) and 1.5(1.2-2.6) vs 2.4 (1.4-3.8) and 2.5 (1.5-3.7), respectively, P < 0.001]. Late HMR and wash-out (inversely) correlated with NT-proBNP r = - 0.652 (P < 0.001) and r = 0.756 (P < 0.001), respectively. Furthermore, late HMR and wash-out (inversely) correlated with cardiac 99mTc-HDP uptake r = - 0.663 (P < 0.001) and r = 0.617 (P < 0.001), respectively.

CONCLUSION

In case of heart failure, 123I-MIBG scintigraphy reflects cardiomyopathy rather than cardiac autonomic neuropathy in ATTRm patients and TTR mutation carriers. 123I-MIBG scintigraphy may already be abnormal before any cardiac bone tracer uptake is visible.

Repurposing Benzbromarone for Familial Amyloid Polyneuropathy: A New Transthyretin Tetramer Stabilizer

Transthyretin (TTR) is a homotetrameric protein involved in human amyloidosis, including familial amyloid polyneuropathy (FAP). Discovering small-molecule stabilizers of the TTR tetramer is a therapeutic strategy for these diseases. Tafamidis, the only approved drug for FAP treatment, is not effective for all patients. Herein, we discovered that benzbromarone (BBM), a uricosuric drug, is an effective TTR stabilizer and inhibitor against TTR amyloid fibril formation. BBM rendered TTR more resistant to urea denaturation, similarly to iododiflunisal (IDIF), a very potent TTR stabilizer. BBM competes with thyroxine for binding in the TTR central channel, with an IC50 similar to IDIF and tafamidis. Results obtained by isothermal titration calorimetry (ITC) demonstrated that BBM binds TTR with an affinity similar to IDIF, tolcapone and tafamidis, confirming BBM as a potent binder of TTR. The crystal structure of the BBM-TTR complex shows two molecules binding deeply in the thyroxine binding channel, forming strong intermonomer hydrogen bonds and increasing the stability of the TTR tetramer. Finally, kinetic analysis of the ability of BBM to inhibit TTR fibrillogenesis at acidic pH and comparison with other stabilizers revealed that benzbromarone is a potent inhibitor of TTR amyloidogenesis, adding a new interesting scaffold for drug design of TTR stabilizers.

CCS/CHFS Heart Failure Guidelines: Clinical Trial Update on Functional Mitral Regurgitation, SGLT2 Inhibitors, ARNI in HFpEF, and Tafamidis in Amyloidosis

In this update, we focus on selected topics of high clinical relevance for health care providers who treat patients with heart failure (HF), on the basis of clinical trials published after 2017. Our objective was to review the evidence, and provide recommendations and practical tips regarding the management of candidates for the following HF therapies: (1) transcatheter mitral valve repair in HF with reduced ejection fraction; (2) a novel treatment for transthyretin amyloidosis or transthyretin cardiac amyloidosis; (3) angiotensin receptor-neprilysin inhibition in patients with HF and preserved ejection fraction (HFpEF); and (4) sodium glucose cotransport inhibitors for the prevention and treatment of HF in patients with and without type 2 diabetes. We emphasize the roles of optimal guideline-directed medical therapy and of multidisciplinary teams when considering transcatheter mitral valve repair, to ensure excellent evaluation and care of those patients. In the presence of suggestive clinical indices, health care providers should consider the possibility of cardiac amyloidosis and proceed with proper investigation. Tafamidis is the first agent shown in a prospective study to alter outcomes in patients with transthyretin cardiac amyloidosis. Patient subgroups with HFpEF might benefit from use of sacubitril/valsartan, however, further data are needed to clarify the effect of this therapy in patients with HFpEF. Sodium glucose cotransport inhibitors reduce the risk of incident HF, HF-related hospitalizations, and cardiovascular death in patients with type 2 diabetes and cardiovascular disease. A large clinical trial recently showed that dapagliflozin provides significant outcome benefits in well treated patients with HF with reduced ejection fraction (left ventricular ejection fraction ≤ 40%), with or without type 2 diabetes.

Heart Failure with Preserved Ejection Fraction-a Concise Review

Purpose of Review

Heart failure with preserved ejection fraction (HFpEF) is a relatively new disease entity used in medical terminology; however, both the number of patients and its clinical significance are growing. HFpEF used to be seen as a mild condition; however, the symptoms and quality of life of the patients are comparable to those with reduced ejection fraction. The disease is much more complex than previously thought. In this article, information surrounding the etiology, diagnosis, prognosis, and possible therapeutic options of HFpEF are reviewed and summarized.

Recent Findings

It has recently been proposed that heart failure (HF) is rather a heterogeneous syndrome with a spectrum of overlapping and distinct characteristics. HFpEF itself can be distilled into different phenotypes based on the underlying biology. The etiological factors of HFpEF are unclear; however, systemic low-grade inflammation and microvascular damage as a consequence of comorbidities associated with endothelial dysfunction, oxidative stress, myocardial remodeling, and fibrosis are considered to play a crucial role in the pathogenesis of a disease. The H₂FPEF score and the HFpEF nomogram are recently validated highly sensitive tools employed for risk assessment of subclinical heart failure.

Summary

Despite numerous studies, there is still no evidence-based pharmacotherapy for HFpEF and the mortality and morbidity associated with HFpEF remain high. A better understanding of the etiological factors, the impact of comorbidities, the phenotypes of the disease, and implementation of machine learning algorithms may play a key role in the development of future therapeutic strategies.

Wild-Type Transthyretin Amyloidosis Occurring in the Ligamentum Flavum of the Cervicothoracic Spine

BACKGROUND

Wild-type transthyretin amyloid (ATTRwt) has been noted to deposit in the ligamentum flavum of the spine. Prior studies have focused on ATTRwt in the lumbar region, but studies discussing its presence in other levels of the spine are lacking. We report on the presentation of patients with confirmed amyloid in the cervicothoracic regions and discuss the literature to date.

METHODS

We retrospectively identified patients at a single institution who underwent surgery for spinal stenosis and had pathologic specimens sent for amyloidosis testing with Congo red staining. ATTRwt was confirmed by the presence of transthyretin amyloid by typing and the absence of mutations in the TTR gene sequence. A final study group of patients with ATTRwt and spinal involvement was established (n = 27).

RESULTS

Of 27 patients with amyloid in the spine, 24 (89%) had amyloid present in the lumbar region, 2 (7%) had amyloid in the cervical region, and 1 (4%) had amyloid in the thoracic region. The median age at which patients in the study underwent surgery was 71 years (interquartile range: 9). Spinal stenosis was the indication for surgery in 26 of 27 (96%) patients. Surgery involved 1 or 2 spinal levels in 24 of 27 (89%) patients.

CONCLUSIONS

ATTRwt amyloid predominantly deposits in the lumbar region, but it can also be present in the cervical and thoracic regions. While the lumbar regions should remain a focus for evaluation of ATTRwt amyloidosis, the cervicothoracic region should not be ignored.

Systemic Amyloidosis Recognition, Prognosis, and Therapy: A Systematic Review

IMPORTANCE

Many patients with systemic amyloidosis are underdiagnosed. Overall, 25% of patients with immunoglobulin light chain (AL) amyloidosis die within 6 months of diagnosis and 25% of patients with amyloid transthyretin (ATTR) amyloidosis die within 24 months of diagnosis. Effective therapy exists but is ineffective if end-organ damage is severe.

OBJECTIVE

To provide evidence-based recommendations that could allow clinicians to diagnose this rare set of diseases earlier and enable accurate staging and counseling about prognosis.

EVIDENCE REVIEW

A comprehensive literature search was conducted by a reference librarian with publication dates from January 1, 2000, to December 31, 2019. Key search terms included amyloid, amyloidosis, nephrotic syndrome, heart failure preserved ejection fraction, and peripheral neuropathy. Exclusion criteria included case reports, non-English-language text, and case series of fewer than 10 patients. The authors independently selected and appraised relevant literature.

FINDINGS

There was a total of 1769 studies in the final data set. Eighty-one articles were included in this review, of which 12 were randomized clinical trials of therapy that included 3074 patients, 9 were case series, and 3 were cohort studies. The incidence of AL amyloidosis is approximately 12 cases per million persons per year and there is an estimated prevalence of 30 000 to 45 000 cases in the US and European Union. The incidence of variant ATTR amyloidosis is estimated to be 0.3 cases per year per million persons with a prevalence estimate of 5.2 cases per million persons. Wild-type ATTR is estimated to have a prevalence of 155 to 191 cases per million persons. Amyloidosis should be considered in the differential diagnosis of adult nondiabetic nephrotic syndrome; heart failure with preserved ejection fraction, particularly if restrictive features are present; unexplained hepatomegaly without imaging abnormalities; peripheral neuropathy with distal sensory symptoms, such as numbness, paresthesia, and dysesthesias (although the autonomic manifestations occasionally may be the presenting feature); and monoclonal gammopathy of undetermined significance with atypical clinical features. Staging can be performed using blood testing only. Therapeutic decision-making for AL amyloidosis involves choosing between high-dose chemotherapy and stem cell transplant or bortezomib-based chemotherapy. There are 3 therapies approved by the US Food and Drug Administration for managing ATTR amyloidosis, depending on clinical phenotype.

CONCLUSIONS AND RELEVANCE

All forms of amyloidosis are underdiagnosed. All forms now have approved therapies that have been demonstrated to improve either survival or disability and quality of life. The diagnosis should be considered in patients that have a multisystem disorder involving the heart, kidney, liver, or nervous system.

Sudden death in lambda light chain AL cardiac amyloidosis: a review of literature and update for clinicians and pathologists

Light chain (AL) amyloidosis is the most common type of systemic amyloidosis, affecting around 10 people per million per year. In Europe, approximately 5000 new diagnosis per year are reported. Deposition of amyloid fibrils derived from antibody light chains are key pathogenic agents in AL amyloidosis. They can be deposited in multiple organs but cardiac involvement carries a major risk of mortality. The prognosis is poor in cases associated with multiple myeloma. The average survival is around 1 year. Up to half of all patients with cardiac amyloidosis die suddenly; 75% ofthose deaths are due to heart failure. Ventricular arrhythmia is also associated with cardiac amyloidosis and unexpected death. It is crucial to make a diagnosis and start treatment at an early stage. Recent data suggest that cardiac amyloidosis has become a treatable and curable condition with a combination of agents targeting multiple steps of the amyloid cascade. ICD implantation may not be as effective for the therapy of light chain (AL) cardiac amyloidosis as supposed earlier. In cases of unexpected and sudden death, autopsy may show unknown conditions and is valuable to assess existing risks for family members. Even after careful autopsy, a proportion of sudden deaths, ranging from 2 to 54%, remain unexplained and this broad range of values is likely due to the heterogeneity of autopsy protocols. Post mortem diagnosis of cardiac amyloidosis still represents a challenge for forensic pathologists. Detailed morphologic study of the heart and a complete histopathologic study are mandatory. Immunohistochemistry is essential for amyloid subclassification. A review of existing literature is performed by the authors and a methodological approach in post mortem diagnosis of light chain AL cardiac amyloidosis is proposed. Both macroscopic and microscopic findings are discussed.

Multi-modality imaging of cardiac amyloidosis: Contemporary update

Cardiac amyloidosis is a heterogeneous and challenging diagnostic disease with poor prognosis that is now being altered by introduction of new therapies. Echocardiography remains the first-line imaging tool, and when disease is suspected on echocardiography, cardiac magnetic resonance imaging and nuclear imaging play critical roles in the non-invasive diagnosis and evaluation of cardiac amyloidosis. Advances in multi-modality cardiac imaging allowing earlier diagnosis and initiation of novel therapies have significantly improved the outcomes in these patients. Cardiac imaging also plays important roles in the risk stratification of patients presenting with cardiac amyloidosis. In the current review, we provide a clinical and imaging focused update, and importantly outline the imaging protocols, diagnostic and prognostic utility of multimodality cardiac imaging in the assessment of cardiac amyloidosis.

Societal costs and burden of hereditary transthyretin amyloidosis polyneuropathy

Background: Hereditary transthyretin amyloidosis polyneuropathy (ATTRv-PN) is a rare life-threatening disease that imposes considerable mortality and morbidity associated with increased costs, high social support and productivity losses. This study aims to estimate the societal costs and burden of ATTRv-PN.Methods: A cost-of-illness (COI) and burden of disease model were specified from a societal perspective, using a prevalence-based approach. Direct and indirect costs were included. Healthcare resource use was retrieved from public databases, previous Portuguese studies and the literature. The burden of disease was expressed in terms of disability-adjusted life years (DALYs), as defined by the World Health Organisation.Results: In 2016, the total annual COI of ATTRv-PN in Portugal was 52,502,796€ and the mean cost per patient was 28,152€ (79% direct; 21% indirect costs). Treatments accounted for 52% of total costs, while 0.18% were devoted to disease prevention. A total of 2056 DALYs were lost, 26% due to disability and 74% due to death.Conclusions: Annual costs and burden of ATTRv-PN were considerable but within the range of other rare diseases. Policies and public interventions to prevent and reduce the burden of disease should be prioritised, since patients experience excess morbidity, mortality and total costs will likely increase in the future.

Identification and typing of cardiac amyloidosis by noninvasive imaging: Two cases for two patterns

Cardiac amyloidosis is a restrictive infiltrative cardiomyopathy burdened by high mortality. The two more common forms are immunoglobulin light-chain amyloidosis and transthyretin-related amyloidosis with different prognoses and treatments. However, distinguishing between them is challenging. Appropriate utilization of the different available imaging techniques in the evaluation of patients with known or suspected cardiac amyloidosis is mandatory. We report two cases with cardiac amyloidosis of different etiology and with distinct imaging patterns. In the first case, the negative 99mTc-diphosphonate imaging was useful to support the diagnosis of cardiac amyloid light-chain; the second case emphasized the utility of whole-body scintigraphy in recognizing transthyretin-related cardiac amyloidosis and the potential role of cadmium-zinc-telluride SPECT imaging for the evaluation of segmental distribution of cardiac disease. Both cases support the growing interest in looking for noninvasive methods to type cardiac amyloidosis in the place of invasive myocardial biopsy highlighting both possibilities and limitations of available imaging techniques in diagnosis and treatment monitoring.

Prediction of Medium-Term Mortality in Japanese Patients With Wild-Type Transthyretin Amyloidosis

Background: The prognostic factors in Japanese patients with wild-type transthyretin amyloidosis (ATTRwt) have not been elucidated. Methods and Results: In this study we retrospectively analyzed the clinical characteristics and outcomes of 47 patients with ATTRwt (mean (±SD) age at diagnosis 80.3±4.6 years; 41 males). Fifteen patients died within 2 years of their diagnosis. Receiver operating characteristic and Kaplan-Meier analyses revealed that the best predictors of 2-year mortality were low serum albumin (≤3.75 g/dL), elevated high-sensitivity cardiac troponin T (hs-cTnT; >0.086 ng/mL), and reduced left ventricular ejection fraction (LVEF; <50%). According to the total number of these 3 risk factors, patients were stratified into 4 subgroups: low risk (no risk factors; n=15), intermediate-low risk (1 risk factor; n=15), intermediate-high risk (2 risk factors; n=7), and high risk (3 risk factors; n=10). The estimated 2-year survival rate of patients classified as low risk, intermediate-low risk, intermediate-high risk, and high risk was 93%, 80%, 83%, and 11%, respectively (P<0.001). Conclusions: Low serum albumin, elevated hs-cTnT, and reduced LVEF are associated with a worse prognosis in Japanese patients with ATTRwt. The combination of these factors may be useful for predicting medium-term mortality in patients with ATTRwt.

Genetic Testing for Diagnosis of Hypertrophic Cardiomyopathy Mimics

Background

Genetic testing is helpful for diagnosis of hypertrophic cardiomyopathy (HCM) mimics. Little data are available regarding the yield of such testing and its clinical impact.

Methods

The HCM genetic database at our center was used for identification of patients who underwent HCM-directed genetic testing including at least 1 gene associated with an HCM mimic ( GLA , TTR , PRKAG2 , LAMP2 , PTPN11 , RAF1 , and DES ). Charts were retrospectively reviewed and genetic and clinical data extracted.

Results

There were 1731 unrelated HCM patients who underwent genetic testing for at least 1 gene related to an HCM mimic. In 1.45% of cases, a pathogenic or likely pathogenic variant in one of these genes was identified. This included a yield of 1% for Fabry disease, 0.3% for familial amyloidosis, 0.15% for PRKAG2 -related cardiomyopathy, and 1 patient with Noonan syndrome. In the majority of patients, diagnosis of the HCM mimic based on clinical findings alone would have been challenging. Accurate diagnosis of an HCM mimic led to change in management (eg, enzyme replacement therapy) or family screening in all cases.

Conclusions

Genetic testing is helpful in the diagnosis of HCM mimics in patients with no or few extracardiac manifestations. Adding these genes to all HCM genetic panels should be considered.

Clinical Analysis of Cardiac Involvement in 53 Patients With Multiple Myeloma Coexistent With Light Chain Amyloidosis

BACKGROUND

We identified 53 patients with multiple myeloma (MM) who had biopsy evidence of light chain amyloidosis (AL), and studied their cardiac involvement and outcomes.

PATIENTS AND METHODS

Our cohort consisted of 53 patients in whom MM and AL were initially diagnosed from July 1, 2006 to June 30, 2016.The diagnosis of MM required > 10% of clonal plasma cells in bone marrow and 1 of the CRAB symptoms, meanwhile, the diagnosis of AL must meet pathologic diagnostic criteria and monoclonal immunoglobulin light chain. Echocardiograms and cardiac biomarker such as N terminal pro B-type natriuretic peptide was used for evaluation of cardiac damage on the baseline and before every cycle of the regimen.

RESULTS

There were 36 men and 17 women with a median age of 59 years; their main organ involvement was kidney (72%) and heart (62%). Of these, 22 patients were treated with a bortezomib-based regimen, and the response rate was more effective than the other 21 patients who received non-bortezomib-based regimens (64% vs. 29%). The median overall survival (OS) for the total cohort was 12 months (P < .05). The median OS of the MM cohort with International Staging System stage I and II together was 34 months, which was longer than that of patients with stage III of 8 months. The median OS in Mayo stages I, II, and III was 38, 8, and 1 months, respectively (P < .05). Cardiac involvement significantly adversely affected survival (6 vs. 40 months), as did systolic blood pressure (< 90 mmHg, 3 vs. 8.5 months).

CONCLUSIONS

Patients coexistent with MM and AL is rare; AL has a negative impact on survival for the total cohort. Especially, cardiovascular dysfunction caused by AL maybe a major determinant of shortening survival.

Cardiac amyloidosis presenting with recurrent ischaemic strokes

A 72-year-old man presented to our service with sudden onset right-sided weakness, aphasia and gaze palsy with diplopia. CT angiogram demonstrated an acute thrombotic occlusion of the distal basilar artery, a basilar infarct and the patient underwent successful thrombectomy. ECG and telemetry demonstrated slow atrial fibrillation (AF). His transthoracic echocardiogram (TTE) showed a reduced ejection fraction of 25% with global hypo-kinesis, a dilated left ventricle (LV) and LV hypertrophy (LVH). Repeat TTE appeared suspicious for an infiltrative cardiomyopathy with LVH and a speckled appearance to the myocardium. Approximately 10 months later, he suffered another ischaemic stroke post-elective cardioversion for AF while on anticoagulation. Cardiac MRI demonstrated areas of delayed gadolinium enhancement consistent with amyloidosis. Fat pad biopsy was positive for amyloidosis. Our patient has made an excellent recovery from the ischaemic strokes and is being managed in our heart failure clinic.

Positive Myocardial Uptake of Bone Scintigraphic Agents Associated with Cardiac Amyloidosis: Frequency of Positive Uptake Data Based on Daily Clinical Practice

Objective: The bone scan plays an important role for detecting number of conditions relating to bones, including: bone cancer or bone metastasis, bone inflammation. Extraosseous uptake, in particular, myocardial uptake, was observed in some patients examined with the bone scans. Positive uptake of ^99mTc-labeled bone radiotracers is associated with cardiac amyloidosis. However, the frequency and cause of positive cardiac ^99mTc-MDP uptake have not been fully studied. In this regard, the aim of this study was to assess the frequency and characteristics of patients with high myocardi-al uptake of bone scintigraphy in daily clinical practice setting. Methods: We retrospectively analyzed 4180 bone scintigraphies performed in daily clinical practice during 7-years period. The intensity of the myocardial uptake was graded based on a visual scale ranging from 0 to 3 points. Score 0 indicates the absence of uptake. Score 1 defined uptake less than that of bone (referred to as the adjacent rib). Uptake similar to that of bone was classified score 2. Score 3 was defined as uptake greater than that of reference bone. Positive myocardial uptake included a visual score 2 or 3. Result: Positive ^99mTc-MDP myocardial uptake occurred in 12 patients among 4180 patients (0.3%). 7 of 12 positive scan patients were consistent with amyloidosis confirmed by biopsy. In these patients, the mean age was 75.6 ± 5.2 years old. Ten cases showed biventricular uptake and 2 showed LV uptake only. Conclusion: Positive cardiac uptake of bone scintigraphic agents was present in 0.3% of bone scintigraphies in a clinical practice setting. This may be a sign of cardiac amyloidosis involvement which may give the presence of extraosseous bone tracer uptake its own importance and a new role.

Hiding in Plain Sight: Cardiac Amyloidosis, an Emerging Epidemic

Amyloidosis is a term used to describe a group of rare heterogeneous diseases that ultimately result in the deposition and accumulation of misfolded proteins. These misfolded proteins, known as amyloids, are associated with a variety of precursor proteins that have amyloidogenic potential. Ultimately, the specific type of amyloidosis is dependent on multiple factors including genetic variability of precursor proteins and the tissue or organ in which the amyloid accumulates. Several types of amyloid have a predilection for the heart and thus contribute to cardiac amyloidosis, a major cause of restrictive cardiomyopathy. Individuals with cardiac amyloidosis present clinically with heart failure with preserved ejection fraction. Although improved diagnostics and increased awareness of cardiac amyloidosis have led to a relative increase in diagnosis, cardiac amyloidosis remains an underrecognized and underdiagnosed cause of heart failure with preserved ejection fraction. It is essential to properly identify cases of cardiac amyloidosis and determine the pathology responsible for the formation of amyloid to appropriately provide management. This review aims to encourage physician awareness of cardiac amyloidosis by focusing on clinical presentation and the distinctions between types. Furthermore, epidemiology is central to understanding the affected demographics and sometimes hereditary nature of the disease. Improved understanding of cardiac amyloidosis will ideally lead to earlier diagnosis and interventions to improve patient outcomes.

Estimating the Prevalence of Transthyretin Amyloid Cardiomyopathy in a Large In-Hospital Database in Japan

INTRODUCTION

Transthyretin amyloid cardiomyopathy (ATTR-CM)-a debilitating, fatal disease resulting from the deposition of transthyretin (TTR) amyloid fibrils-can be hereditary due to mutations in the TTR gene (ATTRm) or wild type (ATTRwt). The global prevalence of ATTR-CM is largely unknown, although likely underestimated, with no formal epidemiological prevalence studies in Japan. This study aimed to estimate the prevalence of ATTR-CM in a large in-hospital database in Japan.

METHODS

This was a retrospective, observational, cross-sectional study which utilized data from all adult patients (aged ≥ 20 years) in the hospital-based Japan Medical Data Vision (MDV) database from January 2010 to September 2018 to estimate the number of currently diagnosed ATTR-CM patients and describe their demographic and clinical characteristics and diagnostic modalities. ATTR-CM patients (ATTRwt and ATTRm) were identified using a range of diagnosis codes that were applied to create broad and narrow definitions of the disease.

RESULTS

Over the 9 years of this study, there were 3255 (155.8 per million adult patients in the MDV database) to 3992 (191.1 per million) diagnoses of ATTRwt and 67 (3.2 per million) to 106 (5.1 per million) diagnoses of ATTRm in the MDV database (based on the narrow and broad definitions, respectively). There were 444 (21.2 per million) diagnoses of amyloid light-chain (AL) amyloidosis. Considering only those patients who were also diagnosed with heart failure, there were 1468 (70.3 per million) to 1798 (86.1 per million) diagnoses of ATTRwt and 50 (2.4 per million) to 61 (2.9 per million) diagnoses of ATTRm. Most ATTRwt patients (~ 90%) did not have a record of endomyocardial or abdominal wall biopsy, or of scintigram.

CONCLUSION

This retrospective study provides an estimate of the number of patients diagnosed with ATTR-CM in a large in-hospital database in Japan over a period of 9 years. Improving awareness of disease prevalence may improve diagnosis and treatment.

FUNDING

Pfizer.