A review of the criteria for non-invasive diagnosis of cardiac transthyretin amyloidosis

Introduction: Cardiac transthyretin (ATTR) amyloidosis is a progressive and fatal infiltrative cardiomyopathy (ATTR-CM) characterized by congestive cardiac failure, often with preserved left ventricular ejection fraction, and significant risk of conduction disease. Diagnosis is often delayed or missed due to poor specificity of echocardiography and the historical requirement for a histological diagnosis, frequently an endomyocardial biopsy. Areas covered: Following a detailed literature review focusing on peer reviewed articles (Pubmed, Cochrane Library, Google Scholar), from 1995 to 2020, alongside international diagnostic guidelines and expert opinion in the field, this article will explore the current non-invasive diagnostic criteria for ATTR-CM including the role of transthoracic echocardiography, cardiac MRI, bone scintigraphy, and assessment for exclusion of a clonal dyscrasia. Expert opinion: ATTR-CM is an emerging and increasingly diagnosed cause of heart failure, particularly in the elderly. Promising novel therapies make accurate and swift diagnosis of the disease vital. With the increasing use of cardiac MRI to investigate cardiomyopathy and repurposing of technetium-labeledbone scintigraphy, clinicians are now often able to diagnose ATTR-CM without recourse to an endomyocardial biopsy

Patisiran for the Treatment of Transthyretin-mediated Amyloidosis with Cardiomyopathy

Transthyretin (TTR) is a tetrameric protein, synthesized primarily by the liver, that acts as a physiological transport protein for retinol and thyroxine. TTR can misfold into pathogenic amyloid fibrils that deposit in the heart and nerves, causing a life-threatening transthyretin amyloidosis cardiomyopathy (ATTR-CM), and a progressive and debilitating polyneuropathy (ATTR-PN). Recent therapeutic advances have resulted in the development of drugs that reduce TTR production. Patisiran is a small interfering RNA that disrupts the complimentary mRNA and inhibits TTR synthesis, and is the first gene-silencing medication licensed for the treatment of ATTR amyloidosis. After encouraging results following the use of patisiran for the treatment of patients with ATTR-PN, there has been increasing interest in the use of patisiran for the treatment of ATTR-CM. Various studies have demonstrated improvements across a wide range of cardiac biomarkers following treatment with patisiran, and have changed the perception of ATTR-CM from being thought of as a terminal disease process, to now being regarded as a treatable disease. These successes represent a huge milestone and have the potential to revolutionize the landscape of treatment for ATTR-CM. However, the long-term safety of patisiran and how best to monitor cardiac response to treatment remain to be determined

Cardiac Amyloidosis: A Review of Current Imaging Techniques

Systemic amyloidosis is a rare, heterogenous group of diseases characterized by extracellular infiltration and deposition of amyloid fibrils. Cardiac amyloidosis (CA) occurs when these fibrils deposit within the myocardium. Untreated, this inevitably leads to progressive heart failure and fatality. Historically, treatment has remained supportive, however, there are now targeted disease-modifying therapeutics available to patients with CA. Advances in echocardiography, cardiac magnetic resonance (CMR) and repurposed bone scintigraphy have led to a surge in diagnoses of CA and diagnosis at an earlier stage of the disease natural history. CMR has inherent advantages in tissue characterization which has allowed us to better understand the pathological disease process behind CA. Combined with specialist assessment and repurposed bone scintigraphy, diagnosis of CA can be made without the need for invasive histology in a significant proportion of patients. With existing targeted therapeutics, and novel agents being developed, understanding these imaging modalities is crucial to achieving early diagnosis for patients with CA. This will allow for early treatment intervention, accurate monitoring of disease course over time, and thereby improve the length and quality of life of patients with a disease that historically had an extremely poor prognosis. In this review, we discuss key radiological features of CA, focusing on the two most common types; immunoglobulin light chain (AL) and transthyretin (ATTR) CA. We highlight recent advances in imaging techniques particularly in respect of their clinical application and utility in diagnosis of CA as well as for tracking disease change over time

A case report in cardiovascular magnetic resonance: the contrast agent matters in amyloid

BACKGROUND: Cardiac amyloidosis is a progressive but underdiagnosed and underappreciated cause of heart failure. In the last few years, cardiovascular magnetic resonance (CMR) has become the gold standard for non invasive diagnosis of cardiac amyloidosis with the characteristic subendocardial late gadolinium enhancement. CASE PRESENTATION: We describe a case of a patient who, in the process of aligning protocols for a trial between different centers, had a paired study with two different contrast agents, Dotarem® and MultiHance®. MultiHance® surprisingly failed to demonstrate the characteristic imaging pattern, showing only non specific late gadolinium enhancement at the inferior right ventricular insertion point and different myocardial extracellular volume fraction compared to the one obtained with Dotarem®. MultiHance® is used by many centres, because its partial blood protein binding is a strength for MR angiography, but late gadolinium enhancement, particularly non-ischemic, appears to be compromised. CONCLUSIONS: This case report suggests that contrast agents should be selected with caution, especially with new therapies lining up for amyloid and CMR being used as exploratory end point in clinical trials

Extracellular volume quantification by dynamic equilibrium cardiac computed tomography in cardiac amyloidosis.

Cardiac involvement determines outcome in patients with systemic amyloidosis. There is major unmet need for quantification of cardiac amyloid burden, which is currently only met in part through semi-quantitative bone scintigraphy or Cardiovascular Magnetic Resonance (CMR), which measures ECVCMR. Other accessible tests are needed

Repeat doses of antibody to serum amyloid P component clear amyloid deposits in patients with systemic amyloidosis

Systemic amyloidosis is a fatal disorder caused by pathological extracellular deposits of amyloid fibrils that are always coated with the normal plasma protein, serum amyloid P component (SAP). The small-molecule drug, miridesap, [(R)-1-[6-[(R)-2-carboxy-pyrrolidin-1-yl]-6-oxo-hexanoyl]pyrrolidine-2-carboxylic acid (CPHPC)] depletes circulating SAP but leaves some SAP in amyloid deposits. This residual SAP is a specific target for dezamizumab, a fully humanized monoclonal IgG1 anti-SAP antibody that triggers immunotherapeutic clearance of amyloid. We report the safety, pharmacokinetics, and dose-response effects of up to three cycles of miridesap followed by dezamizumab in 23 adult subjects with systemic amyloidosis (ClinicalTrials.gov identifier: NCT01777243). Amyloid load was measured scintigraphically by amyloid-specific radioligand binding of 123I-labeled SAP or of 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid. Organ extracellular volume was measured by equilibrium magnetic resonance imaging and liver stiffness by transient elastography. The treatment was well tolerated with the main adverse event being self-limiting early onset rashes after higher antibody doses related to whole body amyloid load. Progressive dose-related clearance of hepatic amyloid was associated with improved liver function tests. 123I-SAP scintigraphy confirmed amyloid removal from the spleen and kidneys. No adverse cardiac events attributable to the intervention occurred in the six subjects with cardiac amyloidosis. Amyloid load reduction by miridesap treatment followed by dezamizumab has the potential to improve management and outcome in systemic amyloidosis

A 24-year experience of autologous stem cell transplantation for light chain amyloidosis patients in the United Kingdom

Autologous stem cell transplantation (ASCT) is considered to be the best method to achieve deep haematological/organ responses and improve survival in selected patients with AL amyloidosis. This field has been led by US centres and is less utilised in Europe. The introduction of effective chemotherapy agents for AL prompted us to re‐evaluate UK outcomes of ASCT in affected patients. A total of 264 AL amyloidosis patients treated with an ASCT between 1994 and 2018 were identified. Patient baseline characteristics, transplant‐related mortality (TRM) and overall survival (OS) were analysed. The median OS post‐ASCT was 87 months [95% confidence interval (CI): 77–106 months]. The median time from ASCT to next treatment was 48 months (95% CI: 29–55 months). A haematological response was achieved in 94·8% of patients and was a strong predictor of time to next treatment [P < 0·0001, hazard ratio (HR) = 1·75, 95% CI = 1·35–2·28] and OS (P = 0·007, HR = 1·91, 95% CI = 1·19–3·07). Organ response was: cardiac (n = 28, 60·9%), renal (n = 101, 76%) and liver (n = 7, 13·5%). Overall TRM was 8·7%, with a significant reduction over time (1994–2000: 18·8%; 2001–2006: 13·6%; 2007–2012: 6·2%; 2013–2018: 1·1%). In conclusion, ASCT is significantly safer and remains a highly effective treatment with excellent long‐term survival; it should be more widely considered as a treatment option for systemic AL amyloidosis

Detection of Lyman-alpha Emitting Galaxies at Redshift z=4.55

Studies of the formation and early history of galaxies have been hampered by the difficulties inherent in detecting faint galaxy populations at high redshift. As a consequence, observations at the highest redshifts (3.5 < z < 5) have been restricted to objects that are intrinsically bright. These include quasars, radio galaxies, and some Ly alpha-emitting objects that are very close to (within ~10 kpc) -- and appear to be physically associated with -- quasars. But the extremely energetic processes which make these objects easy to detect also make them unrepresentative of normal (field) galaxies. Here we report the discovery using Keck spectroscopic observations of two Ly alpha-emitting galaxies at redshift z = 4.55, which are sufficiently far from the nearest quasar (~700 kpc) that radiation from the quasar is unlikely to provide the excitation source of the Ly alpha emission. Instead, these galaxies appear to be undergoing their first burst of star formation, at a time when the Universe was less than one billion years old.Comment: 8 pages, 1 landscape table, and 3 PostScript figures. Uses aaspp4.sty, flushrt.sty, aj_pt4.sty, overcite.sty (style macros available from xxx.lanl.gov) Figure 1 is bitmapped to 100 dpi. The original PostScript version of Fig. 1 is available via anonymous ftp to ftp://hubble.ifa.hawaii.edu/pub/preprints To appear in Natur