A Case of Early Hereditary Transthyretin Amyloid Cardiomyopathy Recognition With Genetic Screening: A Case Report

Background: Transthyretin amyloid cardiomyopathy (ATTR-CM) is one of the most common types of cardiac amyloidosis. Amyloid cardiomyopathy more commonly affects men, elderly, and 3% to 4% of the African-American population. ATTR-CM suspicion and diagnosis is challenging; however, awareness of the disease is increasing, and best practices to identify it are being proposed. The approach to suspected cases of ATTR-CM relies on the presence of heart failure, red flag signs and symptoms, and age >65 or >70 for men and women respectively. Little is known about cases when it presents in early ages. Case: We report a 62-year-old African American male with past medical history of hyperlipidemia, prostate cancer, hypertension, bilateral carpal tunnel surgery that had debuted with a cardiac arrhythmia at age 55 and was diagnosed with heart failure several years later. Restrictive cardiomyopathy was suspected, and genetic screening was sent for ATTRm which confirmed a pathogenic trasnthyretin gene mutation. Endomyocardial biopsy was performed which confirmed cardiac amyloid deposition. Discussion: ATTR-CM is a rare disease with an increasing prevalence. Cases with out of proportion signs and symptoms of heart failure with preserved ejection fractions should raise the suspicion of ATTR-CM despite age.

Machine learning of native T1 mapping radiomics for classification of hypertrophic cardiomyopathy phenotypes

We explored whether radiomic features from T1 maps by cardiac magnetic resonance (CMR) could enhance the diagnostic value of T1 mapping in distinguishing health from disease and classifying cardiac disease phenotypes. A total of 149 patients (n = 30 with no heart disease, n = 30 with LVH, n = 61 with hypertrophic cardiomyopathy (HCM) and n = 28 with cardiac amyloidosis) undergoing a CMR scan were included in this study. We extracted a total of 850 radiomic features and explored their value in disease classification. We applied principal component analysis and unsupervised clustering in exploratory analysis, and then machine learning for feature selection of the best radiomic features that maximized the diagnostic value for cardiac disease classification. The first three principal components of the T1 radiomics were distinctively correlated with cardiac disease type. Unsupervised hierarchical clustering of the population by myocardial T1 radiomics was significantly associated with myocardial disease type (chi2 = 55.98, p < 0.0001). After feature selection, internal validation and external testing, a model of T1 radiomics had good diagnostic performance (AUC 0.753) for multinomial classification of disease phenotype (normal vs. LVH vs. HCM vs. cardiac amyloid). A subset of six radiomic features outperformed mean native T1 values for classification between myocardial health vs. disease and HCM phenocopies (AUC of T1 vs. radiomics model, for normal: 0.549 vs. 0.888; for LVH: 0.645 vs. 0.790; for HCM 0.541 vs. 0.638; and for cardiac amyloid 0.769 vs. 0.840). We show that myocardial texture assessed by native T1 maps is linked to features of cardiac disease. Myocardial radiomic phenotyping could enhance the diagnostic yield of T1 mapping for myocardial disease detection and classification.

325 Dealing with cardiac amyloidosis diagnosis: keep calm and use the magnifying glasses!

Methods and results Case report— male, 71 years old. Past medical history—arterial hypertension, dyslipidemia, tobacco abuse. COPD on nocturnal CPAP therapy. Rheumatic polymyalgia on steroid therapy. Previous unprovoked deep vein thrombosis on anticoagulation with rivaroxaban. Bilateral carpal tunnel surgeries 8 years ago. Spontaneous left biceps tendon rupture 4 year ago. IgA kappa monoclonal gammopathy of undetermined significance (MGUS). Mild interventricular septum (IVS) hypertrophy on echocardiography since 2018. In 2019 IVS was 18 mm with granular sparkling appearance. In February 2020 he was hospitalized for initial heart failure and COPD exacerbation. In 2021 he developed worsening dyspnoea. He underwent cardiological evaluation in a spoke hospital and a cardiac magnetic resonance (CMR) suggested infiltrative cardiomyopathy. Bone scintigraphy showed moderate cardiac uptake (Perugini Score 2). Following haematological evaluation, fat pad biopsy was performed, and amyloid was detected on Congo red staining. Classification of the amyloid fibril protein was not performed. Bone marrow biopsy, even though of suboptimal quality, was negative for amyloid and for plasma cellular infiltration. Bone marrow aspirate showed 11% of plasma cells and multiple myeloma was therefore hypothesized. Recent medical history—he was evaluated in our Cardiac Amyloid Outpatient Clinic in May 2021. He was symptomatic for dyspnoea (NYHA class III) and exercise intolerance, diffuse osteo-muscolar pain, and extremities paresthesia. His blood pressure was on the low side of normality with necessity of anti-hypertensive therapy downgrading. Signs and symptoms of hematological disease were not present. We required to analyse the fat pad specimen in order to perform amyloid fibril protein typing; with immunoelectron microscopy, transthyretin (TTR) was identified as the amyloid fibrils precursor (no light chains could be identified). We considered performing endomyocardial biopsy to exclude the coexistence of ATTR amyloidosis and light chains (AL) amyloidosis in the heart but, given the history, clinical picture, and fat pad biopsy results, we felt that cardiac ATTR was the most probable diagnosis and we decided to proceed with a close cardiological and haematological follow-up. TTR genetic testing is ongoing. Conclusions ATTR cardiac amyloidosis is an emerging cause of heart failure, especially with preserved ejection fraction, in the older population. However, these patients frequently present with dysproteinemias and bone marrow abnormalities, up to multiple myeloma, raising the issue of differential diagnosis between ATTR and AL amyloidosis. According to the latest European Consensus Document, in the presence of cardiac uptake at bone scintigraphy (Grades 1–3) and positive haematologic tests, histological confirmation (usually cardiac) is necessary to subtype amyloid infiltration. In our case, the patient had positive Congo Red-stained fat pad biopsy, but the typing of the amyloid deposition was not performed. After referral to a Center with a Cardiac Amyloid Outpatient Clinic with a specialized Pathology Unit, we could further proceed with diagnostic workup and identify the amyloid deposition as ATTR; of note, fat pad biopsy is positive in just 15–25% of ATTR amyloidosis. Moreover, close collaboration with Hematology was necessary to assess the risk of AL amyloidosis and to provide a close and targeted follow-up. Endomyocardial biopsy was not performed after consideration of the various elements suggestive for ATTR cardiac amyloidosis, but the patient will be evaluated periodically and closely to potentially reassess this decision.

Abstract 17083: Hunting For Clot: Strokes In Patients With Cardiac Amyloid

Case Presentation: A 76-year-old female with history of amyloid light chain (AL) cardiac amyloidosis and prior stroke presented with acute bilateral leg weakness. MRI of the brain revealed subacute infarcts in the right basal ganglia and precentral gyrus as well as chronic left cerebellar infarctions. CT angiogram of the head and neck did not show any significant intracranial or carotid artery disease. All current and previous admission ECGs and telemetry showed sinus rhythm with no atrial arrhythmias. Transthoracic echocardiogram with bubble study noted LV ejection fraction of 62%, normal left atrial size and no evidence of an intracardiac shunt. Despite the lack of traditional indicators, a cardioembolic source was feared given the high risk of intracardiac thrombi in AL amyloid patients. A TEE was performed and confirmed a large left atrial appendage (LAA) thrombus with severely reduced velocities and spontaneous echo contrast (Figure 1). The patient was started on apixaban for secondary stroke prevention. Discussion: Amyloid proteins deposit throughout heart tissue, distorting mechanical function and electric conduction resulting in reduced blood flow and a high risk of intracardiac thrombi that is 10 times that of nonamyloid patients. Patients with cardiac amyloidosis have a high prevalence of atrial arrhythmias, particularly atrial fibrillation, but remain at significant risk of thrombi even in the absence of these arrhythmias, ranging from 3-20%. Risk factors for clot include AL type amyloid and features of worsened hemodynamics such as LV systolic and diastolic dysfunction, elevated heart rates and lower systolic blood pressure. This case demonstrates the importance of aggressively “hunting” for intracardiac thrombi in amyloid patients presenting with stroke even without perceived risk factors, especially given the protective effect of starting anticoagulation.

Genome silencer therapy leading to “regression” of cardiac amyloid load on cardiovascular magnetic resonance—a case report

Background Hereditary or variant transthyretin amyloidosis (ATTRv) is a progressive disease manifesting with neuropathy and/or cardiomyopathy. An early and accurate diagnosis of cardiac amyloidosis is a prerequisite for timely and appropriate patient management, including anti-amyloid therapies, as it is associated with heart failure, conduction disease and arrhythmias, leading to reduced quality of life and early death. Case Summary We present the case of an ATTRv male patient presenting with a mixed amyloidosis phenotype (neuropathy and cardiomyopathy). Cardiac disease manifestation comprised tachyarrhythmias (atrial fibrillation) and conduction abnormalities (AV-block) in addition to segmental left ventricular (LV) hypertrophy (septal wall) due to regionally pronounced amyloid deposits in the basal LV myocardium. Interestingly, by means of serial CMR studies, we were able to demonstrate an impressive and unexpected improvement of cardiomyopathy findings within a relatively short period-of-time after implementation of genome-silencer therapies. Discussion This is our second case report that showed ATTRv cardiomyopathy reversal under anti-amyloid therapy—documented by multiparametric CMR. Our findings support the hypothesis that amyloid infiltration leading to cardiomyopathy is not an irreversible pathological process—but rather a dynamic one, that cannot only be stopped but even reversed (to a certain degree) by currently emerging anti-amyloid therapies. Moreover, the role of serial multi-parametric CMR imaging for surveillance of cardiomyopathy dynamics under these therapies is nicely illustrated.

Diagnostic performance of CMR, SPECT, and PET imaging for the detection of cardiac amyloidosis: a meta-analysis

Background Noninvasive myocardial imaging modalities, such as cardiac magnetic resonance (CMR), single photon emission computed tomography (SPECT), and Positron emission tomography (PET), are well-established and extensively used to detect cardiac amyloid (CA). The purpose of this study is to directly compare CMR, SPECT, and PET scans in the diagnosis of CA, and to provide evidence for further scientific research and clinical decision-making. Methods PubMed, Embase, and Cochrane Library were searched. Studies used CMR, SPECT and/or PET for the diagnosis of CA were included. Pooled sensitivity, specificity, positive and negative likelihood ratio (LR), diagnostic odds ratio (DOR), their respective 95% confidence intervals (CIs) and the area under the summary receiver operating characteristic (SROC) curve (AUC) were calculated. Quality assessment of included studies was conducted. Results A total of 31 articles were identified for inclusion in this meta-analysis. The pooled sensitivities of CMR, SPECT and PET were 0.84, 0.98 and 0.78, respectively. Their respective overall specificities were 0.87, 0.92 and 0.95. Subgroup analysis demonstrated that 99mTc-HMDP manifested the highest sensitivity (0.99). 99mTc-PYP had the highest specificity (0.95). The AUC values of 99mTc-DPD, 99mTc-PYP, 99mTc-HMDP were 0.89, 0.99, and 0.99, respectively. PET scan with 11C-PIB demonstrated a pooled sensitivity of 0.91 and specificity of 0.97 with an AUC value of 0.98. Conclusion Our meta-analysis reveals that SEPCT scans present better diagnostic performance for the identification of CA as compared with other two modalities.