AL Amyloidosis for the Cardiologist and Oncologist: Epidemiology, Diagnosis, and Management

The mechanism of action, pharmacological characteristics, and clinical utility of the amyloid depleter birtamimab for the potential treatment of AL amyloidosis

Amyloid light chain (AL) amyloidosis is a progressive plasma cell disorder caused by amyloid deposition resulting in organ damage and failure. Current standard-of-care treatments target clonal plasma cells, the source of misfolded light chains (amyloid precursors), yet only half of patients with advanced disease survive ≥6 months. The amyloid depleter birtamimab is an investigational humanized monoclonal antibody that binds misfolded κ and λ light chains with high specificity and was designed to neutralize soluble toxic light chain aggregates and promote phagocytic clearance of deposited amyloid. Post hoc analyses from the Phase 3 VITAL trial suggested birtamimab plus standard of care confers a survival benefit in patients with advanced (Mayo Stage IV) AL amyloidosis. AFFIRM-AL (NCT04973137), a Phase 3 confirmatory trial of birtamimab plus standard of care in patients with Mayo Stage IV AL amyloidosis, is ongoing. This review summarizes birtamimab's mechanism of action, attributes, and potential clinical utility.

Anticoagulation in Atrial Fibrillation Associated With Cardiac Amyloidosis: A Narrative Review

Cardiac amyloidosis (CA) involves the abnormal deposition and accumulation of amyloid proteins in the heart muscle. A hallmark of disease progression is declining heart function, which can lead to structural irregularities, arrhythmias, and ultimately heart failure. Atrial fibrillation (AF) is the most common arrhythmia that presents in CA patients, and this arrhythmia is significant because it can moderately increase the risk of patients developing intracardiac thrombi, thereby putting them at risk for thromboembolic events. The management of this complication entails the use of anticoagulants like vitamin K antagonists and direct oral anticoagulants to reduce the risk of thrombus formation. This article seeks to review AF in CA and the use of anticoagulation therapy for the management and reduction of thromboembolic risk. The major conclusions of this review are centered around the need for safe administration of anticoagulant therapy to CA patients, regardless of their CHA2DS2-VASc risk score. This review highlights the importance of taking a multidisciplinary or collaborative approach to CA treatment to ensure that all aspects of this multifaceted disease can be properly managed while minimizing adverse events like bleeding risk and drug-drug interactions.

Moving towards establishing centres of excellence in cardiac amyloidosis: an International Cardio-Oncology Society statement

The prevalence of amyloidosis has been increasing, driven by a combination of improved awareness, evolution of diagnostic pathways, and effective treatment options for both transthyretin and light chain amyloidosis. Due to the complexity of amyloidosis, centralised expert providers with experience in delineating the nuances of confirmatory diagnosis and management may be beneficial. There are many potential benefits of a centre of excellence designation for the treatment of amyloidosis including recognition of institutions that have been leading the way for the optimal treatment of this condition, establishing the expectations for any centre who is engaging in the treatment of amyloidosis and developing cooperative groups to allow more effective research in this disease space. Standardising the expectations and criteria for these centres is essential for ensuring the highest quality of clinical care and community education. In order to define what components are necessary for an effective centre of excellence for the treatment of amyloidosis, we prepared a survey in cooperation with a multidisciplinary panel of amyloidosis experts representing an international consortium. The purpose of this position statement is to identify the essential elements necessary for highly effective clinical care and to develop a general standard with which practices or institutions could be recognised as a centre of excellence.

Cardiac amyloidosis is not a single disease: a multiparametric comparison between the light chain and transthyretin forms

AIMS

Systemic amyloidosis represents a heterogeneous group of diseases resulting from amyloid fibre deposition. The purpose of this study is to establish a differential diagnosis algorithm targeted towards the two most frequent subtypes of CA.

METHODS AND RESULTS

We prospectively included all consecutive patients with ATTR and AL evaluated between 2018 and 2022 in two centres in a score derivation cohort and a different validation sample. All patients had a complete clinical, biomarker, electrocardiographic, and imaging evaluation. Confirmation of the final diagnosis with amyloid typing was performed according to the current international recommendations. The study population included 81 patients divided into two groups: ATTR (group 1, n = 32: 28 variant and 4 wild type) and AL (group 2, n = 49). ATTR patients were younger (50.7 ± 13.9 vs. 60.2 ± 7.3 years, P = 0.0001), and significantly different in terms of NT-proBNP [ATTR: 1472.5 ng/L (97-4218.5) vs. AL 8024 ng/L (3058-14 069) P = 0.001], hs-cTn I [ATTR: 10 ng/L (4-20) vs. AL 78 ng/L (32-240), P = 0.0002], GFR [ATTR 95.4 mL/min (73.8-105.3) vs. AL: 68.4 mL/min (47.8-87.4) P = 0.003]. At similar left ventricular (LV) wall thickness and ejection fraction, the ATTR group had less frequently pericardial effusion (ATTR: 15% vs. AL: 33% P = 0.0027), better LV global longitudinal strain (ATTR: -13.1% ± 3.5 vs. AL: -9.1% ± 4.3 P = 0.04), RV strain (ATTR: -21.9% ± 6.2 vs. AL: -16.8% ± 6 P = 0.03) and better reservoir function of the LA strain (ATTR: 22% ± 12 vs. AL: 13.6% ± 7.8 P = 0.02). Cut-off points were calculated based on the Youden method. We attributed to 2 points for parameters having an AUC > 0.75 (NT-proBNP AUC 0.799; hs-cTnI AUC 0.87) and 1 point for GFR (AUC 0.749) and TTE parameters (GLS AUC 0.666; RV FWS AUC 0.649, LASr AUC 0.643). A score of equal or more than 4 points has been able to differentiate between AL and ATTR (sensitivity 80%, specificity 62%, AUC = 0.798). The differential diagnosis score system was applied to the validation cohort of 52 CA patients showing a sensitivity of 81% with specificity of 77%.

CONCLUSIONS

CA is a complex entity and requires extensive testing for a positive diagnosis. This study highlights a series of non-invasive checkpoints, which can be useful in guiding the decision-making process towards a more accurate and rapid differential diagnosis.

Diagnostic value of left ventricular layer strain and specific regional strain patterns in cardiac amyloidosis and Fabry disease

Aims

Layer-specific left ventricular (LV) strain alterations have been suggested as a specific finding in Fabry disease (FD). Our study aimed to assess the diagnostic value of layer-specific radial strain (RS) indices compared to the established LV regional strain pattern in cardiac amyloidosis (CA) and FD, i.e. apical sparing and posterolateral strain deficiency (PLSD).

Methods and results

We retrospectively analysed the global, subendocardial, subepicardial LV radial strain, the corresponding strain gradient, as well as the regional and global longitudinal strain. The diagnostic accuracy of the diverse LV strain analyses was comparatively assessed using receiver operating characteristic curve and multivariable regression analyses. In 40 FD and 76 CA patients, CA featured more reduced layer strain values [global RS -12.3 (-15.6 to -9.6) in CA vs. -16.7 (-20.0 to -13.6) in FD; P < 0.001; subendocardial RS -22.3 (-27.4 to -15.9) vs. -28.3 (-31.8 to -23.6), P < 0.001; subepicardial RS -6.6 (-8.6 to -4.7) in CA vs. -8.9 (-11.7 to - 6.5) in FD; P < 0.001]. Global radial and longitudinal strain held an area under the curve (AUC) of 0.75 (0.66-0.84) and AUC 0.73 (0.63-0.83). While the apical sparing and PLSD strain pattern showed the highest accuracy as single parameters [AUC 0.87 (0.79-0.95) and 0.81 (0.72-0.89), P < 0.001], the combination of subendocardial RS and the apical sparing pattern featured the highest diagnostic accuracy [AUC 0.92 (0.87-0.97)].

Conclusion

Combining radial strain-derived parameters to the established strain pattern apical sparing and PLSD improve the diagnostic accuracy in the echocardiographic assessment in suspected storage disease.

Appraisal of amyloidosis imaging practices in the Middle East/North Africa (PYP-MENA)

Aims

Whereas recommendations to optimize performance and yield of cardiac scintigraphy studies with bone-seeking tracers have been published, little is known about real-world adherence to these best practices, especially outside North America and Europe. Accordingly, we described imaging practices with this modality in a sample of nuclear laboratories in the Middle East/North Africa (MENA) region.

Methods and results

Laboratories performing radionuclide imaging for cardiac amyloidosis in the MENA region were invited to participate in this study to describe installed camera systems, type and dose of bone-avid tracers used, imaging protocols, and criteria used for study interpretation. Out of 19 invited sites, 10 completed the survey (70% government-run; 90% accredited), sites have been involved with amyloid imaging for a median of 49 months (interquartile range 24-60). The median injected dose was 20 mCi (range 10-25), and PYP was used by 90% of sites in this sample. Planar imaging with single photon emission computed tomography (SPECT) reconstruction was performed at all sites, including seven sites that performed SPECT/CT reconstruction. Lastly, only 50% of sites relied on evidence of myocardial uptake by SPECT to confirm the diagnosis of ATTR cardiomyopathy, while the rest relied on visual assessment and heart/contralateral ratio.

Conclusion

This study is the first to describe variation in imaging practices across sites in the MENA region, especially in acquisition protocols and interpretation standards. Eliminating heterogeneities identified by this study will harmonize image interpretation and reporting and will facilitate successful conduct of regional multi-centre studies.

Light-chain cardiac amyloidosis for the non-expert: pearls and pitfalls

Cardiac amyloidosis (CA) is an uncommon, progressive, and fatal disease; the two main forms that can affect the heart are transthyretin CA and light chain CA (AL-CA). AL-CA is a medical urgency for which a diagnostic delay can be catastrophic for patients' outcome. In this manuscript, we focus on the pearls and pitfalls that are relevant to achieve a correct diagnosis and to avoid diagnostic and therapeutical delays. Through the aid of three unfortunate clinical cases, some fundamental diagnostic aspects are addressed, including the following: first, a negative bone scintigraphy does not exclude CA, with patients with AL-CA frequently showing no or mild cardiac uptake, and its execution should not delay hematological tests; second, fat pad biopsy does not have a 100% sensitivity for AL amyloidosis and, if negative, further investigations should be performed, particularly if the pre-test probability is high. Third, Congo Red staining is not sufficient to reach a definitive diagnosis and amyloid fibrils typing with mass spectrometry, immunohistochemistry, or immunoelectron microscopy is crucial. To achieve a timely and correct diagnosis, all the necessary investigations must be performed, always considering the yield and diagnostic accuracy of each examination.

Prognosis of light chain amyloidosis: a multivariable analysis for survival prediction in patients with cardiac involvement proven by endomyocardial biopsy

BACKGROUND

Cardiac involvement is a main determinant of mortality in light chain (AL) amyloidosis but data on survival of patients with cardiac AL amyloidosis proven by endomyocardial biopsy (EMB) are sparse.

METHODS

This study analysed clinical, laboratory, electrocardiography and echocardiographic parameters for their prognostic value in the assessment of patients with AL amyloidosis and cardiac involvement. Patients with AL amyloidosis who had their first visit to the amyloidosis centre at the University Hospital Heidelberg between 2006 and 2017 (n=1628) were filtered for cardiac involvement proven by EMB. In the final cohort, mortality-associated markers were analysed by univariate and multivariable Cox regression. Cut-off values for each parameter were calculated using the survival time.

RESULTS

One-hundred and seventy-four patients could be identified. Median overall survival time was 1.5 years and median follow-up time was 5.2 years. At the end of the investigation period, 115 patients had died. In multivariable analysis, New York Heart Association-functional class >II (HR 1.65; 95% CI 1.09 to 2.50; p=0.019), left ventricular global longitudinal strain (HR 1.12; 95% CI 1.03 to 1.22; p=0.007), left ventricular end-systolic volume (HR 1.02; 95% CI 1.01 to 1.03; p=0.001), systolic pulmonary artery pressure (HR 0.98; 95% CI 0.96 to 0.99; p=0.027), N-terminal pro-B-type natriuretic peptide (HR 1.57; 95% CI 1.17 to 2.11; p=0.003) and difference in free light chains (HR 1.30; 95% CI 1.05 to 1.62; p=0.017) were independently predictive.

CONCLUSION

Among all patients with AL amyloidosis those with cardiac involvement represent a high-risk population with limited therapy options. Therefore, accurate risk stratification is necessary to identify cardiac amyloidosis patients with favourable prognosis. Incorporation of modern imaging techniques into existing or newly developed scoring systems is a promising option that might enable the implementation of risk-adapted therapeutic strategies.

A Review of Current and Evolving Imaging Techniques in Cardiac Amyloidosis

Purpose of review

Establishing an early, efficient diagnosis for cardiac amyloid (CA) is critical to avoiding adverse outcomes. We review current imaging tools that can aid early diagnosis, offer prognostic information, and possibly track treatment response in CA.

Recent findings

There are several current conventional imaging modalities that aid in the diagnosis of CA including electrocardiography, echocardiography, bone scintigraphy, cardiac computed tomography (CT), and cardiac magnetic resonance (CMR) imaging. Advanced imaging techniques including left atrial and right ventricular strain, and CMR T1 and T2 mapping as well as ECV quantification may provide alternative non-invasive means for diagnosis, more granular prognostication, and the ability to track treatment response.

Summary

Leveraging a multimodal imaging toolbox is integral to the early diagnosis of CA; however, it is important to understand the unique role and limitations posed by each modality. Ongoing studies are needed to help identify imaging markers that will lead to an enhanced ability to diagnose, subtype and manage this condition.

Evaluation of contemporary echocardiographic and histomorphology parameters in predicting mortality in patients with endomyocardial biopsy-proven cardiac AL amyloidosis

Introduction

This study examined the role of echocardiographic and cardiac histomorphology parameters in predicting mortality in patients with cardiac AL amyloidosis.

Methods

Patients with endomyocardial biopsy-proven cardiac AL amyloidosis treated at MD Anderson Cancer Center between 6/2011 and 6/2020 were identified. Stored echocardiographic images and endomyocardial biopsy samples were processed for myocardial strain analysis and a detailed histomorphology characterization.

Results

Of 43 patients; 44% were women and 63% white. Median age was 65 years; 51% underwent stem cell transplantation (SCT). Thirty patients (70%) died during follow up (median follow up: 4.1 years). Lower LA strain (<13.5%) and absence of SCT as a time-varying covariate were significantly associated with increased risk of death in the multivariate cox regression analysis. Higher LV mass and lower RV tricuspid annular plane systolic excursion were associated with increased odds of having ≥5% interstitial amyloid deposition on biopsy in the multivariate logistic regression analysis.

Conclusion

Lower LA strain independently predicted mortality in our cohort, and its performance in the routine assessment of AL amyloidosis may be beneficial. Furthermore, SCT for cardiac AL amyloidosis was associated with improved OS. These findings need to be confirmed by larger studies in the era of contemporary systemic therapies.

Microcalcification and 99mTc-Pyrophosphate Uptake without Increased Bone Metabolism in Cardiac Tissue from Patients with Transthyretin Cardiac Amyloidosis

Transthyretin cardiac amyloidosis (ATTR-CA) is characterized by high ^99mTc-labeled bone tracer uptake in the heart. However, the mechanism of bone tracer uptake into the heart remains controversial. Since bone tracer uptake into metastatic bone tumors is thought to be associated with increased bone metabolism, we examined ^99mTc-pyrophosphate (PYP) scintigraphy findings, endomyocardial biopsy (EMB) tissue findings, and the expression of bone metabolism-related genes in the EMB tissues in patients with ATTR-CA, amyloid light-chain cardiac amyloidosis (AL-CA), and noncardiac amyloidosis (non-CA) in this study. The uptake of ^99mTc-PYP in the heart was significantly higher in the ATTR-CA patients than in the AL-CA and non-CA patients. A higher percentage of ATTR-CA EMB tissue showed von Kossa-positive microparticles: ATTR-CA, 62%; AL-CA, 33%; and non-CA, 0%. Calcified microparticles were identified using transmission electron microscopy. However, none of the osteogenic marker genes, osteoclastic marker genes, or phosphate/pyrophosphate-related genes were upregulated in the EMB samples from ATTR-CA patients compared to those from AL-CA and non-CA patients. These results suggest that active calcification-promoting mechanisms are not involved in the microcalcification observed in the heart in ATTR-CA. The mechanisms explaining bone tracer uptake in the heart, which is stronger than that in the ribs, require further investigation.

Cardiac Amyloidosis: A Rare TTR Mutation Found in an Asian Female

BACKGROUND

Transthyretin cardiac amyloidosis (ATTR) is a life-threatening, debilitating disease caused by abnormal formation and deposit of transthyretin (TTR) protein in multiple tissues, including myocardial extracellular matrix. It can be challenging to diagnose due to the myriad of presenting signs and symptoms. Additionally, numerous TTR mutations exist in certain ethnicities. Interestingly, our patient was discovered to have a very rare Gly67Ala TTR mutation typically not found in individuals of Asian descent. Recent advances in cardiovascular imaging techniques have allowed for earlier recognition and, therefore, management of this disease. Although incurable, there are now new, emerging treatments that are available for symptom control of cardiac amyloidosis, making early diagnosis vital for these patients, specifically their quality of life.

CASE SUMMARY

We outline a case of a 50-year-old Asian female who was initially hospitalized for nausea and vomiting and persistent orthostatic hypotension. She underwent a multitude of laboratory and imaging tests, resulting in a diagnosis of cardiac amyloidosis, which was confirmed to be due to a rare TTR mutation via genetic testing.

CONCLUSIONS

Our objective is to describe various TTR mutations, existing diagnostic imaging modalities, and available treatments, as well as highlight the importance of early screening and awareness of cardiac amyloidosis, allowing for quicker diagnosis and treatment of this disease.

Prevalence and Risk Factors of Cardiac Amyloidosis in Heart Failure: A Systematic Review and Meta-Analysis

AIMS

Heart failure (HF) is one of the leading causes of mortality worldwide. Heart failure is also one of the most common presentations of cardiac amyloidosis (CA). Contemporary epidemiological data of CA in HF patients is lacking. Hence, this systematic review and meta-analysis was conducted to determine the prevalence of amyloidosis in HF patients, and to clarify the risk factors of concomitant CA and HF.

METHODS

A systematic review and meta-analysis was performed. Studies were retrieved from Medline, EMBASE, Scopus and Cochrane library. The search was not restricted in time, type or language of publication. The prevalence of CA in HF grouped according to diagnostic techniques and risk factors of CA with HF was analysed.

RESULTS

Eleven (11) studies were included, involving 3,303 patients. The pooled prevalence of CA in HF was 13.7%. The overall prevalence of CA in HF with preserved ejection fraction was 15.1%, and that of HF with reduced ejection fraction was 11.3%. The main factors associated with the diagnosis of CA in HF included older age, males, raised NT pro-BNP, increased interventricular septal thickness in diastole, apical sparing, and reduced left ventricular systolic function.

CONCLUSION

A high index of clinical suspicion is required to identify HF patients with CA. Supportive investigations may be helpful when clinically correlated. A considerable proportion of HF patients have CA and certain risk factors may be helpful in increasing suspicions of CA in HF.

Removal of cardiac AL amyloid with positive remodelling of cardiomyocytes and of restrictive cardiomyopathy

Herein, we describe histological mobilization of light chain cardiac amyloid documented by sequential left ventricular endomyocardial biopsies. These findings were associated with positive remodelling of cardiomyocytes and of restrictive cardiomyopathy resulting from 14 courses of chemotherapy over 17 years of time. Histological and ultrastructural findings of light chain cardiac amyloid removal led to increase in cardiomyocyte dimension and electrocardiogram voltages, reduction of biventricular wall thickness with improvement of left ventricular diastolic function, and NYHA class shifting from III to I.

Supportive Care and Symptom Management for Patients With Immunoglobulin Light Chain (AL) Amyloidosis

Immunoglobulin light chain (AL) amyloidosis is a disorder of clonal plasma cells characterized by deposition of amyloid fibrils in a variety of tissues, leading to end-organ injury. Renal or cardiac involvement is most common, though any organ outside the central nervous system can develop amyloid deposition, and symptomatic presentations may consequently vary. The variability and subtlety of initial clinical presentations may contribute to delayed diagnoses, and organ involvement is often quite advanced and symptomatic by the time a diagnosis is established. Additionally, while organ function can improve with plasma-cell-directed therapy, such improvement lags behind hematologic response. Consequently, highly effective supportive care, including symptom management, is essential to improve quality of life and to maximize both tolerance of therapy and likelihood of survival. Considering the systemic nature of the disease, close collaboration between clinicians is essential for effective management.

Prognostic Implications of Right Ventricular Systolic Dysfunction in Cardiac Amyloidosis

Left ventricular (LV) systolic dysfunction in cardiac amyloidosis (CA) is associated with poor prognosis. This study aimed to investigate the prognostic implications of right ventricular (RV) systolic dysfunction in CA. A total of 93 patients diagnosed with CA who underwent standard and speckle-tracking echocardiography were included. During a median follow-up of 17 (5 to 38) months, 42 patients (45%) died. Nonsurvivors were more likely to present with immunoglobulin light-chain amyloidosis and New York Heart Association class III to IV heart failure symptoms. Regarding the echocardiographic characteristics, nonsurvivors had a higher LV apical ratio, worse LV diastolic function, and worse RV systolic function (evaluated with both tricuspid annular plane systolic excursion and RV free wall strain). RV free wall strain was independently associated with all-cause mortality in several multivariable Cox regression models and had incremental prognostic value over conventional parameters of RV function when added to a basal model (including heart failure symptoms, amyloidosis phenotype, and LV global longitudinal strain). Based on spline curve analysis and Youden index, a value of 16% for RV free wall strain was identified as the optimal cutoff to predict outcome and patients with RV free wall strain <16% had a significantly worse short- and long-term survival during follow-up (1- and 3-year cumulative survival: 81% vs 31% and 67% vs 20%, respectively, p <0.001). In conclusion, RV systolic dysfunction is independently associated with poor outcome in patients with CA and the use of advanced echocardiographic parameters, such as RV free wall strain, may be of aid for better risk stratification.

[Cardiac amyloidosis: a case report]

Amyloidosis is a multisystem disease caused by infiltration of misfolded proteins; cardiac involvement determines its prognosis. There are several types of precursor proteins capable of causing the disease; however, only two affect the heart, clonal immunoglobulin light chains (AL) and tetrameric transthyretin (TTR) protein. It is an underdiagnosed disease and, in late stages, it has a poor prognosis. We present the case of an older adult patient with progressive cardiac and extracardiac manifestations, as well as laboratory and echocardiographic criteria that brought us closer to the diagnosis of cardiac amyloidosis and also allowed us to assess the prognosis. The patient had a torpid evolution with a fatal outcome. The pathological anatomy studies allowed us to confirm our diagnostic presumption.

Utilization and tolerance of beta-blockers among patients with AL amyloidosis

BACKGROUND

The utilization and clinical impact of beta-blockers (BBs) in cardiac amyloidosis (CA) is largely unexplored.

METHODS

We conducted a retrospective, single-center analysis of indications, timing of initiation, types and doses of BB used, reasons to discontinue BB and association between BB tolerance and outcomes in a cohort of patients with immunoglobulin light chain amyloidosis (AL).

RESULTS

We reviewed 236 patients with AL CA and identified 53 patients taking BB (22.5%). Most patients presented in New York Heart Association Class (NYHA) II or III (74.5%) and 24% presented in Mayo stage IIIB. The most frequent indications for BB initiation were atrial fibrillation (AF) and coronary artery disease (CAD). In most cases (59%) BB was started before the diagnosis of CA. The median duration of BB treatment was 9 months (interquartile range [IQR] 3-24 months). Among patients receiving BB, 28 tolerated BB during follow-up whereas 25 patients discontinued BB. The main causes of BB discontinuation were hypotension and heart failure (HF) exacerbation. Patients intolerant to BB presented with more advanced NYHA class, worse performance status and lower median left ventricular ejection fraction (LVEF) at baseline. At median follow-up duration of 17.7 months, patients who did not tolerate BB had a poor survival.

CONCLUSIONS

Although some patients with CA may have indications for treatment with BB, their use is uncommon and those with more advanced disease tolerate BB poorly. Intolerance to BB in patients with cardiac AL is an indicator of poorer outcome.

Slip-Ups in the Diagnosis of Cardiac Amyloidosis: A Case Fatality in Point

This case report illustrates a tragic example of a "missed diagnosis" of amyloid light-chain (AL) amyloidosis with cardiac involvement that led to progressive heart failure and the ultimate death of the patient. It had a rather atypical presentation in terms of cardiac imaging, although there were certain highly suspicious clinical features, cardiac and otherwise. It also illustrates the importance of selecting the most appropriate assays to establish (or rule out) the presence of monoclonal immunoglobulin consistent with AL amyloidosis, which has a poor clinical prognosis, as unfortunately demonstrated in this case.

Molecular Mechanisms of Cardiac Amyloidosis

Cardiac involvement has a profound effect on the prognosis of patients with systemic amyloidosis. Therapeutic methods for suppressing the production of causative proteins have been developed for ATTR amyloidosis and AL amyloidosis, which show cardiac involvement, and the prognosis has been improved. However, a method for removing deposited amyloid has not been established. Methods for reducing cytotoxicity caused by amyloid deposition and amyloid precursor protein to protect cardiovascular cells are also needed. In this review, we outline the molecular mechanisms and treatments of cardiac amyloidosis.

Global and Regional Variations in Transthyretin Cardiac Amyloidosis: A Comparison of Longitudinal Strain and 99mTechnetium Pyrophosphate Imaging

Background: There is limited data on the head-to-head comparison of ^99mTc-pyrophosphate (PYP) and echocardiographic strain imaging in the assessment of transthyretin (TTR) cardiac amyloidosis. Methods: At Mayo Clinic Arizona, patients that had undergone both a ^99mTc-PYP scan and transthoracic echocardiogram (TTE) within a 90-day period were retrospectively identified for chart review and strain imaging analysis. Patients were divided into two groups according to their ^99mTc-PYP results (PYP+ and PYP -) for the comparison. A standard 17-segment model was used for segmental, regional and global longitudinal strain comparison. A p-value of <0.05 was deemed as significant. Results: A total of 64 patients were included, the mean age was 75.1 ± 13.0 years and 57(89.1%) were male. Comparing the PYP+ to the PYP- group, the left ventricular global longitudinal strain was significantly worse (PYP+ vs. PYP-: -10.5 ± 2.6 vs. -13.1 ± 4.1, P = 0.003). PYP+ patients also had worse regional basal strain (-4.6 ± 2.6 vs. -8.8±4.0, p<0.001) and a trend of worse mid-ventricular strain (-9.6 ± 4.0 vs. -11.7± 4.4, P = 0.07), however, no statistical difference in apical region (-17.6 ± 4.73 vs. -19.0 ± 6.46, P = 0.35). This is consistent with an apical sparing pattern shown by the relative apical longitudinal strain index (1.3 ±0.5 vs. 1.0 ± 0.3, P = 0.008). Segment to segment analysis demonstrated significant difference in strain between PYP+ and PYP- segments in 4 segments: basal inferior (P = 0.006), basal anterolateral (P = 0.01), apical septal (P = 0.002) and apical inferior (P = 0.001). Left ventricular diastolic dysfunction was significantly different with 17 (77.3%) patients in group PYP+ versus 15 (36.6%) in PYP- participants (P = 0.002). Conclusion: Our study suggested that PYP uptake is related to overall worse LV segmental, regional and global longitudinal strain function, as well as diastolic function compared to patients without PYP uptake. This provides important data for clinicians to know the echocardiographic function features related to ^99mTc-PYP uptake and can serve as a hypothesis-generating study for future investigators.

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

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

Cardio-oncology: rationale, aims and future directions

PURPOSE OF REVIEW

Cardiovascular comorbidity among cancer patients is a growing clinical problem with the dramatic improvements in cancer survival. Cardio-oncology has developed as a new medical field dedicated to addressing the complex issues faced by patients who have both cancer and cardiovascular disease. This article explains to the reader what cardio-oncology services provide and the nature of cardiovascular problems caused by the growing array of modern cancer therapies.

RECENT FINDINGS

The list of potentially cardiotoxic cancer therapeutic agents is ever growing and dedicated cardio-oncology experts are required to tackle cardiovascular complications with minimal delay to necessary cancer therapy. Cardio-oncology services originated in academic centres but are now being set up around the world in all hospitals and clinics that provide care to cancer patients. Cardio-oncology plays an increasingly active role at every stage of cancer therapy including baseline risk assessment pretreatment, surveillance and prevention during treatment, response to acute complications and assessment in survivors post cardiotoxic treatments. New treatment strategies exist to optimize cancer treatment so it can be completed safely.

SUMMARY

In the present review, we explore the rationale, aims and roles of cardio-oncology, as well as future directions, which will certainly require multidisciplinary international collaboration.

Multimodality imaging for the diagnosis of infiltrative cardiomyopathies

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

Arrhythmic Sudden Cardiac Death and the Role of Implantable Cardioverter-Defibrillator in Patients with Cardiac Amyloidosis-A Narrative Literature Review

Cardiac amyloidosis (CA) is considered to be associated with an increased risk of sudden cardiac death (SCD) due to ventricular tachyarrhythmias and electromechanical dissociation. However, current arrhythmic risk stratification and the role of an implantable cardioverter-defibrillator (ICD) for primary prevention of SCD remains unclear. This article provides a narrative review of the literature on electrophysiological abnormalities in the context of ventricular arrhythmias in patients with CA and the role of ICD in terms of survival benefit in this group of patients.

The State of the Heart Biopsy: A Clinical Review

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

Cardiac Care of Patients with Cardiac Amyloidosis

Cardiac amyloidosis, the majority of cases of which are due to immunoglobulin light chain amyloidosis (AL) and transthyretin amyloidosis (ATTR), affects different aspects of the heart and cardiovascular system. Amyloid-induced cardiomyopathy, clinically manifesting with heart failure and electrophysiological abnormalities, has distinct characteristics compared to non-amyloid cardiomyopathies. Accordingly, specific management strategies are required. This paper will review the cardiovascular manifestations of patients with cardiac amyloidosis and their suggested treatment strategies, emphasizing the importance of multidisciplinary care.