Current Trends in Diagnosis and Management of Cardiac Amyloidosis

Tolerability and effectiveness of beta-blockers in patients with cardiac amyloidosis: A systematic review and meta-analysis

OBJECTIVE

This systematic review aimed to assess the tolerability of patients with cardiac amyloidosis (CA) to beta-blockers (BBs) and evaluate its association with adverse outcomes.

METHODS

We performed a comprehensive search from January 1, 2000 to October 20, 2023. Studies examining BB use and tolerance or the relationship between BB use and outcomes in patients with CA were included. Pooled adjusted hazard ratios (aHRs) for all-cause mortality were calculated using random- and fixed-effects models.

RESULTS

Eight observational studies involving 4002 patients with CA (87.5% with transthyretin CA [ATTR-CA] and 12.5% with immunoglobulin light chain CA [AL-CA]) were assessed. BBs were used by 52.5% of the patients. However, 26.3% of the patients discontinued BBs because of hypotension, bradycardia, or fatigue. Regarding the association between BB use and all-cause death, four studies were identified that included 2874 patients with ATTR-CA and 16 patients with AL-CA. The meta-analysis revealed no apparent relationship between BB use and all-cause mortality (pooled aHR = 0.78, 95% confidence interval (CI) = 0.40-1.51). Two studies on patients with ATTR-CA found no impact of BB use on all-cause mortality in the subgroup with left ventricular ejection fraction (LVEF) > 40%, but conflicting results exist for those with LVEF ≤40% (pooled aHR = 0.78, 95% CI = 0.40-1.54).

CONCLUSION

The limited number of observational studies that predominantly enrolled patients with ATTR-CA showed that BBs were used in almost half of the patients with CA, with varying tolerability. However, no significant association was observed between BB use and all-cause mortality.

Cardiac Amyloidosis: A Contemporary Review of Medical and Surgical Therapy

Amyloidosis is a systemic disease initiated by deposition of misfolded proteins in the extracellular space, due to which multiple organs may be affected concomitantly. Cardiac amyloidosis, however, remains a major cause of morbidity and mortality in this population due to infiltrative /restrictive cardiomyopathy. This review attempts to focus on contemporary medical and surgical therapies for the different types of cardiac amyloidosis. Amyloidosis affecting the heart are predominantly of the transthyretin type (acquired in the older or genetic in the younger patients), and the monoclonal immunoglobulin light chain (AL) type which is solely acquired. A rare form of secondary amyloidosis AA type can also affect the heart due to excessive production and accumulation of the acute-phase protein called Serum Amyloid A" (SAA) in the setting of chronic inflammation, cancers or autoinflammatory disease. More commonly AA amyloidosis is seen in the liver and kidney. Other rare types are Apo A1 and Isolated Atrial Amyloidosis (AANF). Medical therapies have made important strides in the clinical management of the two common types of cardiac amyloidosis. Surgical therapies such as mechanical circulatory support and cardiac transplantation should be considered in appropriate patients. Future research using AI driven algorithms for early diagnosis and treatment as well as development of newer genetic engineering technologies will drive improvements in diagnosis, treatment and patient outcomes.

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

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

Physiology, Diagnosis and Treatment of Cardiac Light Chain Amyloidosis

AL (light-chain) amyloidosis is a systemic disease in which amyloid fibers are formed from kappa or lambda immunoglobulin light chains, or fragments thereof, produced by a neoplastic clone of plasmocytes. The produced protein is deposited in tissues and organs in the form of extracellular deposits, which leads to impairment of their functions and, consequently, to death. Despite the development of research on pathogenesis and therapy, the mortality rate of patients with late diagnosed amyloidosis is 30%. The diagnosis is delayed due to the complex clinical picture and the slow progression of the disease. This is the type of amyloidosis that most often contributes to cardiac lesions and causes cardiac amyloidosis (CA). Early diagnosis and correct identification of the type of amyloid plays a crucial role in the planning and effectiveness of therapy. In addition to standard histological studies based on Congo red staining, diagnostics are enriched by tests to determine the degree of cardiac involvement. In this paper, we discuss current diagnostic methods used in cardiac light chain amyloidosis and the latest therapies that contribute to an improved patient prognosis.

Diagnostic challenges in systemic amyloidosis: a case report with clinical and laboratorial pitfalls

Currently, there is growing evidence in the literature warning of misdiagnosis involving amyloidosis and chronic inflammatory demyelinating polyneuropathy (CIDP). Although inducing clinical manifestations outside the peripheral nervous system, light chain and transthyretin amyloidosis may initially present with peripheral neuropathy, which can be indistinguishable from CIDP, leading to a delay in the correct diagnosis. Besides, the precise identification of the amyloid subtype is often challenging. This case report exemplifies clinical and laboratory pitfalls in diagnosing amyloidosis and subtyping amyloid, exposing the patient to potentially harmful procedures.

Amyloidoma: a review and case report

Amyloidoma is a solitary mass of amyloid protein that arises in patients with or without evidence of systemic amyloidosis, and can be found in a variety of different organ systems. Herein, we describe three cases of localized biopsy-positive amyloidomas with no evidence of systemic involvement-primary amyloidoma. Our cases include a patient with a paraspinal soft tissue amyloidoma, a patient with multiple primary amyloidomas involving the thoracic cavity and flank, and a patient with insulin-injection induced amyloidoma of the left shoulder. We present these cases to provide further insights into the clinical presentation of this uncommon clinical entity. We review the pathophysiology of amyloidosis and discuss our cases in the context of previous reports of amyloidoma.

Other types of diffuse liver disease: is there a way to do it?

There are a variety of less common diffuse liver diseases that can be asymptomatic or cause severe liver dysfunction. For the majority of them, the association of clinical, laboratory, and imaging findings are needed to narrow the differential diagnosis. In this article, we will review and describe the rarer diffuse liver diseases including drug-related liver disease, inflammatory and infectious diseases, and deposition disorders such as amyloidosis, glycogen storage disease, Wilson's disease, and alpha-1 antitrypsin deficiency. Abdominal radiologists should be familiar with the imaging features of different types of diffuse liver diseases to help the multidisciplinary team involved in the treatment of these patients. The data related to some of these conditions are scarce and sometimes experimental, but we want to demonstrate to the reader the value of imaging techniques in their analysis and introduce the potential of new imaging methods.

Diagnosis of genetic amyloidosis through the analysis of transthyretin gene mutation using high-resolution melting

Transthyretin amyloidosis can be either the wild-type (ATTR-wt) or the hereditary form (ATTR-m) with autosomal dominant inheritance. ATTR seems to be an underdiagnosed disease, despite now being recognized as one of the most frequent causes of heart failure (HF) with preserved ejection fraction. The confirmation of diagnosis includes a genetic analysis as a critical step to distinguish between ATTR-wt and hereditary amyloidosis. The present study aimed to evaluate the potential application of High-Resolution Melting (HRM) analysis for identifying gene mutations in patients with suspected ATTR-m. We have adapted and validated the use of HRM for TTR mutations. We, therefore, sequenced the TTR gene and used HRM in a group of 134 patients suspected of suffering from amyloidosis. Seven patients were diagnosed with mutations in the TTR gene (p.Glu74Gln, heterozygous p.Val142Ile, and homozygous p.Val142Ile). HRM is capable of clearly detecting these TTR mutations, including the heterozygous and homozygous variants. The results show a 100% correlation between the HRM study and TTR sequencing. These results support future studies of applying HRM analysis as a diagnostic approach for ATTR-m, mainly for epidemiological studies.

A retrospective analysis of treatment outcomes in 45 patients with cardiac light-chain amyloidosis: a single-center experience in Japan

The prognosis of cardiac light-chain (AL) amyloidosis is considered to be very poor. We studied the treatment efficacy and outcomes by retrospectively analyzing the clinical results of 45 patients with cardiac AL amyloidosis treated at our hospital between September 2008 and March 2016. The group of patients analyzed included 29 males and 16 females with a median age of 68 years. Their baseline median NT-proBNP, cTnT, and dFLC were 3167 pg/ml, 0.080 ng/ml, and 286.17 mg/l, respectively. Twenty-eight patients were in Cardiac Stage (CS) III and 17 patients were in Revised Prognostic Stage (RPS) IV. At the median follow-up of 10 months, the median overall survival (OS) was 16 months and 3-year OS was 35.9%. The patients in CS III showed significantly poorer survival rate than those in CS I or II (3-year OS: 12.2% vs. 65.8%, p = 0.0115) and the patients in RPS IV showed significantly poorer survival rate than those in RPS I, II, or III (3-year OS: 11.0% vs. 53.3%, p = 0.000914). Regardless of the therapeutic approaches, patients who achieved hematological CR or cardiac organ response demonstrated significantly improved prognosis. Therefore, achievement of hematological and organ responses is important in the treatment of cardiac AL amyloidosis.

Improving sensitivity of amyloid detection by Congo red stain by using polarizing microscope and avoiding pitfalls

Systemic amyloidosis is a devastating group of disorders for which there is no current cure. The treatment goal is to reduce the burden of amyloidogenic protein precursors. The treatment is only effective if applied early in the disease process before significant and irreversible end organ damage has taken place. Congo red is still the standard stain used in most histopathology laboratories to identify amyloid material in tissues. The identification of Congophilic amyloid material is challenging because of multiple interfering factors. Here we describe improved sensitivity of identifying Congophilic materials in histologic sections using a metallurgical polarized microscope specifically constructed for polarized microscopy. The microscope is equipped with strain-free optics, matching polarizers, dis-integrated compensators, and a circular mobile stage. Compared to a standard clinical microscope, this setup significantly improves sensitivity of identifying amyloid material in Congo red-stained slides. We also describe the deleterious effect of plastic coverslip which can interfere with the ability to examine the slides under polarized light. We present a series of 10 different patients who had cardiac, brain, and salivary gland biopsies that were either equivocal or deemed negative using a standard clinical microscope but were positive using the equipment described above. These samples were confirmed to be positive by other methods including electron microscopy. We conclude that use of the correct equipment is needed before ruling out amyloidosis in tissue sections.

Senile Systemic Amyloidosis: An Underdiagnosed Disease

Senile systemic amyloidosis is caused by a non-mutated form of transthyretin with the heart being the major organ involved. This infiltrative cardiomyopathy usually presents as slowly progressive heart failure.

An 82-year-old female patient was admitted for newly diagnosed heart failure. A year later she presented with decompensated heart failure and syncope. Inpatient work-up showed persistently elevated troponin and N-terminal-pro BNP levels, rapid progression to severe left ventricular concentric hypertrophy, and sinus pauses on the Holter. Cardiac MRI revealed diffuse late gadolinium enhancement in the left ventricle. The demonstration of amyloid protein with the clinical findings and complementary investigations allowed for the diagnosis of senile systemic amyloidosis.

Transthyretin amyloid neuropathy has earlier neural involvement but better prognosis than primary amyloid counterpart: an answer to the paradox?

OBJECTIVE

To systematically compare transthyretin with primary amyloid neuropathy to define their natural history and the underlying mechanisms for differences in phenotype and natural history.

METHODS

All patients with defined amyloid subtype and peripheral neuropathy who completed autonomic testing and electromyography at Mayo Clinic Rochester between 1993 and 2013 were included. Medical records were reviewed for time of onset of defined clinical features. The degree of autonomic impairment was quantified using the composite autonomic severity scale. Comparisons were made between acquired and inherited forms of amyloidosis.

RESULTS

One hundred one cases of amyloidosis with peripheral neuropathy were identified, 60 primary and 41 transthyretin. Twenty transthyretin cases were found to have Val30Met mutations; 21 had other mutations. Compared to primary cases, transthyretin cases had longer survival, longer time to diagnosis, higher composite autonomic severity scale scores, greater reduction of upper limb nerve conduction study amplitudes, more frequent occurrence of weakness, and later non-neuronal systemic involvement. Four systemic markers (cardiac involvement by echocardiogram, weight loss > 10 pounds, orthostatic intolerance, fatigue) in combination were highly predictive of poor survival in both groups.

INTERPRETATION

These findings suggest that transthyretin has earlier and greater predilection for neural involvement and more delayed systemic involvement. The degree and rate of systemic involvement is most closely related to prognosis. Ann Neurol 2016;80:401-411.

Systemic amyloidosis

Tissue deposition of protein fibrils causes a group of rare diseases called systemic amyloidoses. This Seminar focuses on changes in their epidemiology, the current approach to diagnosis, and advances in treatment. Systemic light chain (AL) amyloidosis is the most common of these conditions, but wild-type transthyretin cardiac amyloidosis (ATTRwt) is increasingly being diagnosed. Typing of amyloid fibrils, a critical determinant of therapy, has improved with the wide availability of laser capture and mass spectrometry from fixed histological tissue sections. Specific and accurate evaluation of cardiac amyloidosis is now possible using cardiac magnetic resonance imaging and cardiac repurposing of bone scintigraphy tracers. Survival in AL amyloidosis has improved markedly as novel chemotherapy agents have become available, but challenges remain in advanced disease. Early diagnosis, a key to better outcomes, still remains elusive. Broadening the amyloid-specific therapeutic landscape to include RNA inhibitors, fibril formation stabilisers and inhibitors, and immunotherapeutic targeting of amyloid deposits holds promise to transform outcomes in systemic amyloidoses.

Abnormal stress echocardiography findings in cardiac amyloidosis

BACKGROUND

Cardiac involvement in immunoglobulin light chain (amyloid light chain, AL) amyloidosis is characterized by myocardial interstitial deposition but can also cause obstructive deposits in the coronary microvasculature.

METHODS

We retrospectively identified 20 patients who underwent stress echocardiography within 1 year prior to the histologic diagnosis of AL amyloidosis. Only patients with cardiac amyloidosis and no known obstructive coronary disease were included.

RESULTS

Stress echocardiograms (13 exercise; 7 dobutamine) were performed for evaluation of dyspnea and/or chest pain. Stress-induced wall motion abnormalities (WMAs) occurred in 11 patients (55%), 4 of whom had normal left ventricular wall thickness. Coronary angiogram was performed in 9 of 11 patients and demonstrated no or mild epicardial coronary artery disease. Seven (54%) patients had an abnormal exercise blood pressure which occurred with similar likelihood between those with and without stress-induced WMAs.

CONCLUSIONS

Stress-induced WMAs and abnormal exercise blood pressure may occur in patients with cardiac AL amyloidosis despite the absence of significant epicardial coronary artery disease. This finding should raise the possibility of cardiac amyloidosis even in the absence of significant myocardial thickening.

Clinical and echocardiographic characteristics for differentiating between transthyretin-related and light-chain cardiac amyloidoses

Differential diagnosis between transthyretin (TTR) and immunoglobulin light-chain (AL) cardiac amyloidoses is essential due to significantly different prognoses and therapeutic options. Therefore, clinical characteristics of patients with biopsy-proven cardiac amyloidosis were investigated to differentiate TTR from AL amyloidosis. From September 2006 to May 2014, 46 patients were confirmed to have cardiac amyloidosis (TTR, n = 28; AL, n = 18) in our institute. The median age of patients with TTR amyloidosis was 78 years (range 61-90) with 27 (96 %) males, while that of patients with AL amyloidosis was 66 (range 52-76) with 12 (67 %) males. There were no statistically significant differences in echocardiographic findings regarding left ventricular (LV) systolic function or diastolic dysfunction between the two groups. Interestingly, serum brain natriuretic peptide (BNP) levels in patients with AL amyloidosis were significantly higher than those in TTR amyloidosis patients. In contrast, the LV wall was significantly thicker in patients with TTR amyloidosis than in those with AL amyloidosis. Therefore, the ratio of BNP to LV mass index (LVMI) at presentation in AL amyloidosis patients was significantly higher than that in TTR patients (6.7 vs 2.9, p = 0.0006). A BNP-LVMI ratio of less than 3.5 had a diagnostic sensitivity and specificity for TTR amyloidosis of 71 and 83 %, respectively. One-year overall survival was 88.7 % in the patients with TTR amyloidosis and 23.7 % in the patients with AL amyloidosis. Our analysis indicates that the BNP-LVMI ratio, as well as age and sex, may be useful parameters for distinguishing TTR from AL cardiac amyloidosis.

A Routine PET/CT Protocol with Streamlined Calculations for Assessing Cardiac Amyloidosis Using (18)F-Florbetapir

INTRODUCTION

Cardiac amyloidosis is a rare condition characterized by the deposition of well-structured protein fibrils, proteoglycans, and serum proteins as amyloid. Recent work has shown that it may be possible to use (18)F-Florbetapir to image cardiac amyloidosis. Current methods for assessment include invasive biopsy techniques. This work enhances foundational work by Dorbala et al. by developing a routine imaging and analysis protocol using (18)F-Florbetapir for cardiac amyloid assessment.

METHODS

Eleven patients, three healthy controls and eight myloid positive patients, were imaged using (18)F-Florbetapir to assess cardiac amyloid burden. Four of the patients were also imaged using (82)Rb-Chloride to evaluate possible (18)F-Florbetapir retention because of reduced myocardial blood flow. Quantitative methods using modeling, SUVs and SUV ratios were used to define a new streamlined clinical imaging protocol that could be used routinely and provide patient stratification.

RESULTS

Quantitative analysis of (18)F-Florbetapir cardiac amyloid data were compiled from a 20-min listmode protocol with data histogrammed into two static images at 0-5, 10-15, or 15-20 min. Data analysis indicated the use of SUVs or ratios of SUVs calculated from regions draw in the septal wall were adequate in identification of all healthy controls from amyloid positive patients in this small cohort. Additionally, we found that it may be possible to use this method to differentiate patients suffering from AL vs. TTR amyloid.

CONCLUSION

This work builds on the seminal work by Dorbala et al. by describing a short (18)F-Florbetapir imaging protocol that is suitable for routine clinical use and uses a simple method for quantitative analysis of cardiac amyloid disease.

Imaging mass spectrometry analysis of renal amyloidosis biopsies reveals protein co-localization with amyloid deposits

Amyloidosis is a heterogeneous group of protein misfolding diseases characterized by deposition of amyloid proteins. The kidney is frequently affected, especially by immunoglobulin light chain (AL) and serum amyloid A (SAA) amyloidosis as the most common subgroups. Current diagnosis relies on histopathological examination, Congo red staining, or electron microscopy. Subtyping is done by immunohistochemistry; however, commercially available antibodies lack specificity. The purpose of this study was to identify and map amyloid proteins in formalin-fixed paraffin-embedded tissue sections using matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis in an integrated workflow. Renal amyloidosis and non-amyloidosis biopsies were processed for histological and MS analysis. Mass spectra corresponding to the congophilic areas were directly linked to the histological and MS images for correlation studies. Peptides for SAA and AL were detected by MALDI IMS associated to Congo red-positive areas. Sequence determination of amyloid peptides by LC-MS/MS analysis provided protein distribution and identification. Serum amyloid P component, apolipoprotein E, and vitronectin proteins were identified in both AA and AL amyloidosis, showing a strong correlation with Congo red-positive regions. Our findings highlight the utility of MALDI IMS as a new method to type amyloidosis in histopathological routine material and characterize amyloid-associated proteins that may provide insights into the pathogenetic process of amyloid formation.

Cardiac amyloidosis in a heart transplant patient - A case report and retrospective analysis of amyloidosis evolution

Cardiac amyloidosis is a very rare cause of heart failure in heart transplant recipients but an important differential diagnosis in cases of progressive cardiac failure. We report a 72-year-old male patient with the diagnosis of senile systemic amyloidosis (SSA) in a transplanted heart 15 years after transplantation by the initial diagnosis of the dilated cardiomyopathy. Additionally performed immunohistochemical analysis with anti-transthyretin antibody of the cardiac biopsies of the last 15 years enabled the possibility to show the evolution of this disease with characteristic biphasic pattern.

Hypertension is associated with preamyloid oligomers in human atrium: a missing link in atrial pathophysiology?

Background

Increasing evidence indicates that proteotoxicity plays a pathophysiologic role in experimental and human cardiomyopathy. In organ‐specific amyloidoses, soluble protein oligomers are the primary cytotoxic species in the process of protein aggregation. While isolated atrial amyloidosis can develop with aging, the presence of preamyloid oligomers (PAOs) in atrial tissue has not been previously investigated.

Methods and Results

Atrial samples were collected during elective cardiac surgery in patients without a history of atrial arrhythmias, congestive heart failure, cardiomyopathy, or amyloidosis. Immunohistochemistry was performed for PAOs using a conformation‐specific antibody, as well as for candidate proteins identified previously in isolated atrial amyloidosis. Using a myocardium‐specific marker, the fraction of myocardium colocalizing with PAOs (PAO burden) was quantified (green/red ratio). Atrial samples were obtained from 92 patients, with a mean age of 61.7±13.8 years. Most patients (62%) were male, 23% had diabetes, 72% had hypertension, and 42% had coronary artery disease. A majority (n=62) underwent aortic valve replacement, with fewer undergoing coronary artery bypass grafting (n=34) or mitral valve replacement/repair (n=24). Immunostaining detected intracellular PAOs in a majority of atrial samples, with a heterogeneous distribution throughout the myocardium. Mean green/red ratio value for the samples was 0.11±0.1 (range 0.03 to 0.77), with a value ≥0.05 in 74 patients. Atrial natriuretic peptide colocalized with PAOs in myocardium, whereas transthyretin was located in the interstitium. Adjusting for multiple covariates, PAO burden was independently associated with the presence of hypertension.

Conclusion

PAOs are frequently detected in human atrium, where their presence is associated with clinical hypertension.

Novel drugs targeting transthyretin amyloidosis

Transthyretin amyloidosis (ATTR) is either a hereditary disease related to a mutation in the transthyretin gene that leads to neuropathy and/or cardiomyopathy or an acquired disease of the elderly that leads to restrictive cardiomyopathy. The prevalence of this disease is higher than once thought and awareness is likely to increase amongst physicians and in particular cardiologists. Until recently there have been no treatment options for this disease except to treat the heart failure with diuretics and the neuropathy symptomatically. However, there are several emerging pharmacologic therapies designed to slow or stop the progression of ATTR. This article reviews novel therapeutic drugs that work at different points in the pathogenesis of this disease attempting to change its natural history and improve outcomes.

Osteopontin: a novel predictor of survival in patients with systemic light-chain amyloidosis

BACKGROUND

Troponin-T (cTnT) and NT-proBNP provide prognostic information in light-chain amyloidosis (AL). Thus, these biomarkers are widely used in clinical routine for risk stratification. Recently, plasma level of osteopontin (OPN), a secreted phosphoglycoprotein expressed by a variety of cell types, has been reported as a risk predictor in various cardiovascular diseases.

METHODS

OPN was determined retrospectively in 150 consecutive patients newly diagnosed with AL amyloidosis. All patients were evaluated according to a routine protocol including electrocardiography, echocardiography and laboratory testing.

RESULTS

Mean OPN was 591 ± 37 ng/mL. Cardiac involvement was established in 83 (55.3%). Median OPN plasma level were associated with number of organs involved, renal function, eligibility for high-dose melphalan chemotherapy and autologous stem cell transplantation, and severity of cardiac amyloidosis. Median follow-up was 19.2 months. 1-year all-cause-survival was 83.4%. The cut-offs discriminating 1-year all-cause-mortality for NT-proBNP, troponin T, and OPN were 2544 ng/L, 0.035 µg/L, and 426.8 ng/mL, respectively. Outcome was worse in patients with biomarkers above the individual ROC derived cut-off. A significant improvement of survival was observed in patients with cTNT >0.035 µg/L or NT-proBNP >2544 ng/L and OPN below ROC-derived cut-off of 426.8 ng/mL as compared to patients with OPN above 426.8 ng/L. No further discrimination was achieved by OPN in the cohorts of low troponin T or low NT-proBNP, respectively. Separate multivariate models identified OPN (cut-off 426.8 ng/mL) and troponin T (cut-off 0.035 µg/L) as independent predictors of all-cause-mortality.

CONCLUSIONS

These data demonstrated that OPN appears to be a valuable marker in the clinical routine for evaluation of patients with AL amyloidosis, especially if it is used in combination with cTNT and/or NT-proBNP.

Recent advances in the diagnosis and management of cardiac amyloidosis

The heart is commonly involved in various forms of amyloidosis and cardiomyopathy is a major cause of morbidity and mortality in these patients. Diagnosis of cardiac amyloidosis is often delayed due to nonspecific presenting symptoms and failure to recognize early signs of amyloid heart disease on routine cardiac imaging. Treatment of cardiac amyloidosis depends upon the type of amyloid protein. Systemic chemotherapy with or without stem cell transplantation is used to treat immunoglobulin-related amyloidosis and liver transplantation is used for familial transthyretin amyloidosis in select patients. Clinical trials with siRNA for the treatment of transthyretin amyloid cardiomyopathies and amyloid protein stabilizers are ongoing. Prognosis depends on the type of amyloid protein with poorer outcomes noted in immunoglobulin light-chain amyloidosis. Supportive care forms the cornerstone of management and advancements in cardiac imaging and proteomics are expected to positively impact our ability to diagnose, prognosticate and treat cardiac amyloidosis.

Disease-specific differences of left ventricular rotational mechanics between cardiac amyloidosis and hypertrophic cardiomyopathy

Left ventricular (LV) twist (LVT) and untwisting (LVUT) rate are global and thorough parameters of LV function. The aim of the present study was to investigate the differences in LV rotational mechanics between patients with cardiac amyloidosis (CA) and hypertrophic cardiomyopathy (HCM). Twenty consecutive patients with CA, 20 consecutive patients with HCM, and 20 consecutive subjects without evidence of structural heart disease were included. Cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) imaging was performed to evaluate biventricular function, LV mass index, and presence/extent of LGE. Feature-tracking analysis was applied to LV basal and apical short-axis images to determine peak LVT, time to peak LVT, peak LVUT rate, and time to peak LVUT rate. Peak LVT and peak LVUT rate were significantly impaired in patients with CA compared with controls (P < 0.05 for both). In patients with HCM, peak LVT was increased (P < 0.05) compared with controls, whereas peak LVUT rate was preserved (P > 0.05). Time to peak LVUT rate was significantly prolonged in patients with CA and in patients with HCM compared with controls (ANOVA P < 0.001). At multivariate analysis, age (P = 0.007), LV ejection fraction (P = 0.035) and extent of LGE (P < 0.001) were independently related to peak LVT, and LV mass index (P = 0.015) and extent of LGE (P = 0.004) were independently related to peak LVUT rate, whereas extent of LGE (P < 0.001) was the only variable independently related to time to peak LVUT rate. In conclusion, CA and HCM have specific behavior of LV rotational mechanics. The extent of LGE significantly influences the LV rotational mechanics.

Yield of noncardiac biopsy for the diagnosis of transthyretin cardiac amyloidosis

Transthyretin (ATTR) cardiac amyloidosis may be because of mutant transthyretin causing familial amyloid cardiomyopathy (FAC) or wild-type transthyretin causing systemic senile amyloidosis (SSA). Histologic confirmation is often challenging and may require endomyocardial biopsy (EMB). The purpose of this study was to determine the frequency of amyloid protein deposition in positive noncardiac organ biopsy or fat aspiration in patients with ATTR cardiac amyloidosis. The medical records of 286 patients (mean age 66 ± 11, 85% men) with a diagnosis of ATTR cardiac amyloidosis at our institution who underwent noncardiac biopsy or subcutaneous fat aspiration were reviewed, including 186 patients (65%) with FAC and 100 patients (35%) with SSA. One hundred and thirty-one patients (46%) had EMB, all of which were positive. There were 210 patients (73%) with positive noncardiac tissue sampling, including 175 patients (94%) with FAC and 35 patients (35%) with SSA (p <0.001). There were 141 patients (76%) with FAC and 84 patients (84%) with SSA who underwent fat aspiration, and 67% and 14% were positive, respectively, whereas 100 (54%) and 64 (64%) underwent bone marrow biopsy, and 41% and 30% were positive, respectively. Rectal and sural nerve biopsies were performed in 52 (28%) and 54 (29%) patients with FAC and were positive in 81% and 83%, respectively. Biopsy of other noncardiac sites was performed with relatively lower frequency. In conclusion, although EMB is more commonly required to establish the diagnosis of SSA than FAC, noncardiac biopsy or fat aspiration could be considered as initial testing in patients evaluated for ATTR cardiac amyloidosis with characteristic echocardiography findings.

Quirks of dye nomenclature. 2. Congo red

The history, origin, identity, chemistry and uses of Congo red are described. Originally patented in 1884, Congo red soon found applications in dyeing cotton, as a pH indicator for chemists and as a biological stain. Unlike the majority of the 19th century synthetic dyes, it still is available commercially.