Obstructive intramural coronary amyloidosis and myocardial ischemia are common in primary amyloidosis

Cardiac Amyloidosis: A Comprehensive Review of Imaging Findings

Cardiac amyloidosis is an infiltrative cardiomyopathy caused by the deposition of insoluble amyloid fibrils in the myocardium, leading to abnormal cardiac function and heart failure. Diagnosis is often challenging due to its diverse symptoms and related comorbidities. Although endomyocardial biopsy is the gold standard for diagnosis, a complete diagnostic approach often includes non-invasive methods such as Cardiac Magnetic Resonance (CMR) and nuclear medicine techniques. Nuclear medicine bone-seeking agents are useful for diagnosing the transthyretin (ATTR) amyloidosis subtype. CMR is especially useful when echocardiography results are inconclusive or for differentiating cardiac amyloidosis from other conditions like hypertrophic cardiomyopathy. CMR provides a comprehensive evaluation of morphological and functional abnormalities, inversion time, late gadolinium enhancement, and can include advanced techniques such as T1 mapping and extracellular volume quantification for diagnostic and prognostic purposes. This review outlines how CMR and nuclear medicine are integral to the diagnostic process for cardiac amyloidosis, emphasizing their crucial roles and the synergy between various diagnostic techniques in assessing suspected cases. ESSENTIALS: REQUIRED SUMMARY STATEMENT: Nuclear medicine PYP scans and CMR play a pivotal role in the non-invasive diagnosis of cardiac amyloidosis, alongside other essential diagnostic modalities.

Identification of fibrinogen Aα-chain as an amyloid precursor protein in a case of canine coronary artery amyloidosis

Spontaneous amyloid deposition occurs in the coronary arteries in older dogs, but the pathogenesis, including the precursor protein, is not known. We conducted proteome analysis using liquid chromatography-tandem mass spectrometry to identify the amyloid precursor protein in a 13-y-old male mixed-breed dog with amyloid deposition in intramural coronary arteries, and identified fibrinogen Aα-chain. This form of amyloidosis is characterized by the deposition of amyloid derived from fibrinogen Aα-chains, which has been reported previously only in humans and Japanese squirrels. Within amyloid deposits in the intramural coronary arteries of our canine case, the αC connector region was identified in abundance, whereas in humans and Japanese squirrels, the amyloid arises from the αC domain. Thus, even if amyloid is formed by the same protein, the amyloid-forming peptide and the anatomic site of deposition in our case differed from that in humans and Japanese squirrels.

Chest pain and coronary artery disease in cardiac amyloidosis: Prevalence, mechanisms, and clinical implications

Amyloidosis is a systemic disease affecting multiple organs, and often presents with cardiac involvement, with 2 primary underlying pathologies: amyloid light chain- and transthyretin cardiac amyloidosis. Chest pain can occur in both types with variable clinical presentations. This narrative review describes the relationship between cardiac amyloidosis (CA) and chest pain. A PubMed search (June 03. 2024) identified 393 articles related to chest pain in CA. Twenty-eight studies, in English and with full text, were selected. Articles included were case reports, reviews, perfusion- and autopsy studies. In CA patients 10%-20% report chest pain as the initial symptom preceding the diagnosis, and the overall prevalence of chest pain is 38% of patients with CA and it is related to an increased risk of heart failure hospitalization. The mechanisms leading to chest pain in CA patients include increased left ventricular diastolic pressure, infiltration of amyloid fibrils inside and around coronary arteries, and amyloid compression of the microvasculature. The mechanisms commonly lead to elevations of plasma troponin levels, which are higher in amyloid patients with chest pain compared to amyloid patients without chest pain. Symptomatic treatment of chest pain can be challenging due to the low tolerability of medical therapy and poor outcomes of coronary interventions in alleviating the pain and with a higher rate of complications. Our review underscores the importance of recognizing chest pain as a CA symptom, particularly in the elderly. Persistent troponin elevation without coronary artery disease could indicate CA. Screening-based and longitudinal studies are crucial for understanding the relationship between chest pain and CA. Acknowledging the significance of chest pain in CA may facilitate early intervention and improve patient outcomes.

Regional variation in technetium pyrophosphate (PYP) uptake in transthyretin cardiac amyloidosis (ATTR-CA) and concomitant myocardial infarction: A case series

- Diffuse and patchy myocardial uptake of Tc-99m PYP is well established in cases of ATTR-CA. - Chronic myocardial infarction leads to regional myocardial thinning and lack of vascular supply can present as regional sparing 'cold spot' on Tc-99m PYP imaging. - The absence of Tc-99m PYP uptake in vascular regions should raise the possibility of underlying scar.

Chest pain in a patient with transthyretin cardiac amyloidosis: A case report

Key Clinical Message

Patients with transthyretin cardiac amyloidosis (ATTR-CM) commonly present with dyspnea, fatigue, and edema. In our case, the main presentation was exertional angina, which was atypical in patients with ATTR-CM and should be paid more attention to.

Abstract

A 54-year-old woman was admitted with a complaint of exertional chest pain, and she had a history of hypertension. The results of the electrocardiogram and echocardiography revealed the clues of cardiac amyloidosis, and the patient was finally diagnosed with transthyretin cardiac amyloidosis, then she received tafamidis, and the symptoms improved significantly.

Clinical Interpretation of Serum Troponin in the Era of High-Sensitivity Testing

Cardiac troponin (Tn) plays a central role in the evaluation of patients with angina presenting with acute coronary syndrome. The advent of high-sensitivity assays has improved the analytic sensitivity and precision of serum Tn measurement, but this advancement has come at the cost of poorer specificity. The role of clinical judgment is of heightened importance because, more so than ever, the interpretation of serum Tn elevation hinges on the careful integration of findings from electrocardiographic, echocardiographic, physical exam, interview, and other imaging and laboratory data to formulate a weighted differential diagnosis. A thorough understanding of the epidemiology, mechanisms, and prognostic implications of Tn elevations in each cardiac and non-cardiac etiology allows the clinician to better distinguish between presentations of myocardial ischemia and myocardial injury-an important discernment to make, as the treatment of acute coronary syndrome is vastly different from the workup and management of myocardial injury and should be directed at the underlying cause.

Cardiac Troponin in Patients With Light Chain and Transthyretin Cardiac Amyloidosis: JACC: CardioOncology State-of-the-Art Review

Cardiac amyloidosis (CA) is an infiltrative disease caused by amyloid fibril deposition in the myocardium; the 2 forms that most frequently involve the heart are amyloid light chain (AL) and amyloid transthyretin (ATTR) amyloidosis. Cardiac troponin (cTn) is the biomarker of choice for the detection of myocardial injury and is frequently found to be elevated in patients with CA, particularly with high-sensitivity assays. Multiple mechanisms of myocardial injury in CA have been proposed, including cytotoxic effect of amyloid precursors, interstitial amyloid fibril infiltration, coronary microvascular dysfunction, amyloid- and non-amyloid-related coronary artery disease, diastolic dysfunction, and heart failure. Regardless of the mechanisms, cTn values have relevant prognostic (and potentially diagnostic) implications in both AL and ATTR amyloidosis. In this review, the authors discuss the significant aspects of cTn biology and measurement methods, potential mechanisms of myocardial injury in CA, and the clinical application of cTn in the management of both AL and ATTR amyloidosis.

Trends in incidence and clinical outcome of non-ST elevation myocardial infarction in patients with amyloidosis in the United States, 2010-2020

Study objective

To assess temporal changes in clinical profile and in-hospital outcome of patients with amyloidosis presenting with non-ST elevation myocardial infarction, NSTEMI.

Design/setting

We conducted a retrospective observational study using the National Inpatient Sample (NIS) database from January 1, 2010, to December 31, 2020.

Main outcomes

Primary outcome of interest was trend in adjusted in-hospital mortality in patients with amyloidosis presenting with NSTEMI from 2010 to 2020. Our secondary outcomes were trend in rate of coronary revascularization, and trend in duration of hospitalization.

Results

We identified 272,896 hospitalizations for amyloidosis. There was a temporal increase in incidence of NSTEMI among patients aged 18-44 years from 15.5 % to 28.0 %, a reverse trend was observed in 45-64 years: 22.1 % to 17.7 %, p = 0.043. There was no statistically significant difference in rate of coronary revascularization from 2010 to 2020; 16.3 % to 14.2 %, p = 0.86. We observed an increased odds of all-cause in-hospital mortality in patients with NSTEMI compared to those without NSTEMI (aOR = 2.2, 95 % CI: 1.9-2.6, p < 0.001) but there was a decrease trend in mortality from 21.5 % to 11.3 %, p = 0.013 for trend. Hospitalization duration was also observed to decreased from 14.1 days to 10.9 days during the study period (p = 0.055 for trend).

Conclusion

In patients with amyloidosis presenting with NSTEMI, there was increased incidence of NSTEMI among young adults, a steady trend in coronary revascularization, and a decreasing trend of adjusted all-cause in-hospital mortality and length of hospitalization from 2010 to 2020 in the United States.

Chest pain in cardiac amyloidosis: occurrence, causes and prognostic significance

BACKGROUND

Chest pain is experienced by patients with cardiac amyloidosis (CA), but a systematic investigation of its frequency, underlying etiologies and clinical significance is lacking.

METHODS

Clinical, echocardiographic, laboratory characteristics, available coronary arteries imaging and endomyocardial biopsy (EMB) findings of 174 patients with CA (n = 104 with transthyretin, ATTR; n = 70 with light chains, AL) were analyzed.

RESULTS

Chest pain was reported in 66 (38%) CA patients. Compared to those without, patients with chest pain had more frequently a history of coronary artery disease (CAD) (27% vs 15%, p = 0.048) and heart failure (HF) symptoms (62% vs 43%, p = 0.015), higher high sensitivity troponin I (hs-cTnI, 101 vs 65 ng/L, p = 0.032) and higher brain natriuretic peptide (597 vs 407 ng/L, p = 0.024). Among CA patients with chest pain undergoing coronary arteries imaging (n = 37), obstructive CAD was detected in 14 (38%), 13 of whom with ATTR-CA. Of these 37 patients, EMB was available in 10 and vascular/perivascular amyloid deposition was detected in 4/5 (80%) of AL-CA patients and 1/5 ATTR-CA. Among patients with suspected acute coronary syndrome (n = 22), obstructive CAD was detected in 9/17 (53%) ATTR-CA and 0/5 AL-CA; hs-cTnI levels were similar between those with and without obstructive CAD. During a follow-up of 17 (8-34) months, chest pain was a significant predictor of HF hospitalization (HR1.86, 95% CI 1.02-3.39, p = 0.042), even after adjustment for CA subtype and CAD.

CONCLUSION

Chest pain is a common symptom in patients with CA, reflects a more advanced cardiac impairment and predicts future HF hospitalization. The etiology of chest pain seems to differ, with obstructive CAD more frequent in ATTR-CA whilst amyloid vascular/perivascular involvement more common in AL-CA.

Coronary artery bypass grafting for triple vessel disease in cardiac amyloidosis

Cardiac amyloidosis is a rare condition with an estimated incidence of 18-55 per 100 000 person-years. It is associated with either immunoglobulin light chain (AL) or transthyretin amyloid (ATTR), both of which result in a restrictive cardiomyopathy complicated initially by diastolic dysfunction and subsequently followed by biventricular systolic heart failure. Untreated cardiac amyloidosis carries an extremely poor prognosis with an estimated median survival time of less than 1 year in AL and 4 years in ATTR amyloidosis. This is the sixth described report of coronary artery bypass grafting in patients with underlying cardiac amyloidosis.

Prevalence, incidence and clinical outcomes of epicardial coronary artery disease among transthyretin amyloidosis cardiomyopathy patients

BACKGROUND

Transthyretin amyloidosis cardiomyopathy (ATTR-CM) patients are often older and may be at risk for obstructive epicardial coronary artery disease (oeCAD). While ATTR-CM may cause small vessel coronary disease, the prevalence and clinical significance of oeCAD is not well described.

METHODS AND RESULTS

The prevalence and incidence of oeCAD and its association with all-cause mortality and hospitalization among 133 ATTR-CM patients with ≥ 1-year follow-up was evaluated. The mean age was 78 ± 9 years, 119 (89%) were male, 116 (87%) had wild-type and 17 (13%) had hereditary subtypes. Seventy-two (54%) patients underwent oeCAD investigations, with 30 (42%) receiving a positive diagnosis. Among patients with a positive oeCAD diagnosis, 23 (77%) were diagnosed prior to ATTR-CM diagnosis, 6 (20%) at the time of ATTR-CM diagnosis, and 1 (3%) after ATTR-CM diagnosis. Baseline characteristics between patients with and without oeCAD were similar. Among patients with oeCAD, only 2 (7%) required additional investigations, intervention or hospitalization after ATTR-CM diagnosis. After a median follow-up of 27 months there were 37 (28%) deaths in the study population, including 5 patients with oeCAD (17%). Fifty-six (42%) patients in the study population required hospitalization, including 10 patients with oeCAD (33%). There was no significant difference in the rates of death or hospitalization among ATTR-CM patients with and without oeCAD, and oeCAD was not significantly associated with either outcome by univariable regression analysis.

CONCLUSIONS

While oeCAD is prevalent in ATTR-CM patients, this diagnosis is frequently known at time of ATTR-CM diagnosis and characteristics are similar to patients without oeCAD.

The major factor of left ventricular systolic dysfunction in patients with cardiac amyloidosis: Amyloid overload or microcirculation impairment?

Purpose

Amyloid overload and microcirculation impairment are both detrimental to left ventricular (LV) systolic function, while it is not clear which factor dominates LV functional remodeling in patients with cardiac amyloidosis (CA). The purpose of this study was to investigate the major factor of LV systolic dysfunction using cardiac magnetic resonance imaging.

Materials and methods

Forty CA patients and 20 healthy controls were included in this study. The CA group was divided into two subgroups by the left ventricular ejection fraction (LVEF): patients with reduced LVEF (LVEF < 50%, rLVEF), and patients with preserved LVEF (LVEF ≥ 50%, pLVEF). The scanning sequences included cine, native and post-contrast T1 mapping, rest first-pass perfusion and late gadolinium enhancement. Perfusion and mapping parameters were compared among the three groups. Correlation analysis was performed to evaluate the relationship between LVEF and mapping parameters, as well as the relationship between LVEF and perfusion parameters.

Results

Remarkably higher native T1 value was observed in the rLVEF patients than the pLVEF patients (1442.2 ± 85.8 ms vs. 1407.0 ± 93.9 ms, adjusted p = 0.001). The pLVEF patients showed significantly lower slope dividing baseline signal intensity (slope%BL; rLVEF vs. pLVEF, 55.1 ± 31.0 vs. 46.2 ± 22.3, adjusted p = 0.001) and a lower maximal signal intensity subtracting baseline signal intensity (MaxSI-BL; rLVEF vs. pLVEF, 43.5 ± 23.9 vs. 37.0 ± 18.6, adjusted p = 0.003) compared to the rLVEF patients. CA patients required more time to reach the maximal signal intensity than the controls did (all adjusted p < 0.01). There was no significant correlation between LVEF and first-pass perfusion parameters, while significant negative correlation was observed between LVEF and native T1 (r = -0.434, p = 0.005) in CA patients.

Conclusion

Amyloid overload in the myocardial interstitium may be the major factor of LV systolic dysfunction in CA patients, other than microcirculation impairment.

Capillaries as a Therapeutic Target for Heart Failure

Prognosis of heart failure remains poor, and it is urgent to find new therapies for this critical condition. Oxygen and metabolites are delivered through capillaries; therefore, they have critical roles in the maintenance of cardiac function. With aging or age-related disorders, capillary density is reduced in the heart, and the mechanisms involved in these processes were reported to suppress capillarization in this organ. Studies with rodents showed capillary rarefaction has causal roles for promoting pathologies in failing hearts. Drugs used as first-line therapies for heart failure were also shown to enhance the capillary network in the heart. Recently, the approach with senolysis is attracting enthusiasm in aging research. Genetic or pharmacological approaches concluded that the specific depletion of senescent cells, senolysis, led to reverse aging phenotype. Reagents mediating senolysis are described to be senolytics, and these compounds were shown to ameliorate cardiac dysfunction together with enhancement of capillarization in heart failure models. Studies indicate maintenance of the capillary network as critical for inhibition of pathologies in heart failure.

New Advanced Imaging Parameters and Biomarkers-A Step Forward in the Diagnosis and Prognosis of TTR Cardiomyopathy

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an infiltrative disorder characterized by extracellular myocardial deposits of amyloid fibrils, with poor outcome, leading to heart failure and death, with significant treatment expenditure. In the era of a novel therapeutic arsenal of disease-modifying agents that target a myriad of pathophysiological mechanisms, timely and accurate diagnosis of ATTR-CM is crucial. Recent advances in therapeutic strategies shown to be most beneficial in the early stages of the disease have determined a paradigm shift in the screening, diagnostic algorithm, and risk classification of patients with ATTR-CM. The aim of this review is to explore the utility of novel specific non-invasive imaging parameters and biomarkers from screening to diagnosis, prognosis, risk stratification, and monitoring of the response to therapy. We will summarize the knowledge of the most recent advances in diagnostic, prognostic, and treatment tailoring parameters for early recognition, prediction of outcome, and better selection of therapeutic candidates in ATTR-CM. Moreover, we will provide input from different potential pathways involved in the pathophysiology of ATTR-CM, on top of the amyloid deposition, such as inflammation, endothelial dysfunction, reduced nitric oxide bioavailability, oxidative stress, and myocardial fibrosis, and their diagnostic, prognostic, and therapeutic implications.

The Cardiac Dysfunction Caused by Metabolic Alterations in Alzheimer's Disease

A progressive defect in the energy generation pathway is implicated in multiple aging-related diseases, including cardiovascular conditions and Alzheimer's Disease (AD). However, evidence of the pathogenesis of cardiac dysfunction in AD and the associations between the two organ diseases need further elucidation. This study aims to characterize cellular defects resulting in decreased cardiac function in AD-model. 5XFAD mice, a strain expressing five mutations in human APP and PS1 that shows robust Aβ production with visible plaques at 2 months and were used in this study as a model of AD. 5XFAD mice and wild-type (WT) counterparts were subjected to echocardiography at 2-, 4-, and 6-month, and 5XFAD had a significant reduction in cardiac fractional shortening and ejection fraction compared to WT. Additionally, 5XFAD mice had decreased observed electrical signals demonstrated as decreased R, P, T wave amplitudes. In isolated cardiomyocytes, 5XFAD mice showed decreased fraction shortening, rate of shortening, as well as the degree of transient calcium influx. To reveal the mechanism by which AD leads to cardiac systolic dysfunction, the immunoblotting analysis showed increased activation of AMP-activated protein kinase (AMPK) in 5XFAD left ventricular and brain tissue, indicating altered energy metabolism. Mito Stress Assays examining mitochondrial function revealed decreased basal and maximal oxygen consumption rate, as well as defective pyruvate dehydrogenase activity in the 5XFAD heart and brain. Cellular inflammation was provoked in the 5XFAD heart and brain marked by the increase of reactive oxygen species accumulation and upregulation of inflammatory mediator activities. Finally, AD pathological phenotype with increased deposition of Aβ and defective cognitive function was observed in 6-month 5XFAD mice. In addition, elevated fibrosis was observed in the 6-month 5XFAD heart. The results implicated that AD led to defective mitochondrial function, and increased inflammation which caused the decrease in contractility of the heart.

Multisystem Amyloidosis in a Coal Miner with Silicosis: Is Exposure to Silica Dust a Cause of Amyloid Deposition?

The over-secretion of monoclonal immunoglobulin light chains by clonal B cells followed by the aggregation and extracellular deposition of fibrillar deposits are responsible forthe clinical course AL amyloidosis. It is well documented that silica significantly increases the number of immunoglobulin-secreting cells. In the present paper, we report on a coal miner with silicosis and fast progressing primary amyloidosis with predominantly heart, kidney, and lung manifestations. Severeheart failure due to myocardial hypertrophy resulted in the patient’s death. We conclude that long-term environmental silica exposure and silica deposition may contribute to the development of monoclonal gammopathy and amyloidosis due to chronic stimulus and the dysregulation of the immune system.

A case report-facing blues in cardiac amyloidosis: no more a zebra

Background

Cardiac amyloidosis presentation in an affected individual can be varied. We describe a patient who had the entire spectrum of involvement in his life time. Initially presented as an ischaemic heart disease and later developed complete heart block (CHB) and frank cardiomyopathy. Increased load of amyloid caused lead-tissue interface disruption resulting in high pacing thresholds with difficulty in capture during permanent pacemaker implantation requiring a novel strategy of management.

Case summary

A 65-year-old male presented with two episodes of syncope with a history of gradually progressive dyspnoea of 6 months duration along with lower limb swelling for last 1–2 months. He had a history of drug-eluting stent implantation for stable ischaemic heart disease 4 years back. Now he presented with a CHB and a transthoracic echocardiogram hinted towards a restrictive physiology and an infiltrative disease. Cardiac magnetic resonance imaging could not be done in view of the incompatible temporary pacemaker on which the patient was dependent. Abdominal fat pad biopsy was positive for amyloid. He was taken up for permanent pacemaker implantation; however, multiple attempts could not achieve desired threshold and capture amplitudes in the right ventricular apex, septum, or outflow region. The lead was placed in the coronary sinus and a stent was placed proximally to trap the lead behind the deployed stent. Threshold and impedance were satisfactory. Cardiac biopsy subsequently confirmed aTTR amyloidosis.

Discussion

The patient had an ischaemic heart disease, conduction disease, and cardiomyopathy as the manifestation of cardiac amyloidosis. While two-dimensional echo is the screening tool of choice, cardiac biopsy remains the gold standard of diagnosis for amyloidosis. Cardiac pacing comes with its own unique set of challenges in patients with advanced amyloid cardiomyopathy and have to be overcome for symptomatic benefit of the patient. Coronary sinus may be utilized in such patients for single-site ventricular pacing and placing a stent may help to anchor the lead when placed within it.

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.

Cardiac amyloidosis mimicking acute coronary syndrome: a case report and literature review

BACKGROUND

Cardiac amyloidosis, a progressive cardiac disease, results from the accumulation of undegraded proteinaceous substrates in the extracellular matrix of the heart. It may present as acute coronary syndrome (ACS); therefore, a clear distinction remains challenging in clinical practice. We describe a case of cardiac amyloidosis mimicking ACS.

CASE SUMMARY

A 72-year-old man experienced chest discomfort for 2 days. He gradually developed dyspnoea during the preceding month. Electrocardiogram (ECG) showed sinus rhythm with right bundle branch block and low voltage. Echocardiography revealed concentric left ventricular thickening, biatrial dilation, and preserved ejection fraction with predominantly left ventricular basal hypokinesis. Serial testing of the cardiac biomarkers showed persistently increased high-sensitive cardiac troponin T levels and normal serum creatine kinase myocardial band levels. He was diagnosed with ACS with haemodynamic stability. However, coronary angiography demonstrated non-obstructive coronary arteries. Furthermore, significant macroglossia and periorbital purpura were noticed. Laboratory investigations revealed elevated serum immunoglobulin free light chain (FLC) kappa and lambda levels with an increased FLC ratio. Histological analysis of the biopsied abdominal skin confirmed amyloidosis.

DISCUSSION

Cardiac amyloidosis often presents as restrictive cardiomyopathy. The usual symptoms include dyspnoea and peripheral oedema. Chest pain may manifest rarely, leading to misdiagnosis as coronary artery disease. Some findings suggestive of cardiac amyloidosis include clinical signs such as amyloid deposits, dyspnoea, low ECG voltage, and basal-predominant hypokinesis with relative apical sparing in echocardiography. Serum FLC test and abdominal skin biopsy can confirm the diagnosis of amyloidosis when a myocardial biopsy is not feasible.

Negative bone scintigraphy in wild-type transthyretin cardiac amyloidosis

BACKGROUND

Amyloidosis is a rare systemic disease due to the extracellular tissue deposition of a fibrillar-shaped misfolded protein, called amyloid. Only two types of proteins commonly affect the heart leading to an infiltrative cardiomyopathy: immunoglobulin light chain and transthyretin (TTR) cardiac amyloidosis (CA). Despite the promising role of emerging imaging modalities, such as strain echocardiography, cardiac magnetic resonance and bone scintigraphy, its diagnosis is still often missed or delayed due to their inherent limitations and to a nonspecific clinical scenario with frequent concomitance of cardiac comorbidities. The gold standard for a definite diagnosis still remains endomyocardial biopsy, but in rare cases Congo Red staining could provide false negative results, as in our case, requiring immunoelectron microscopy.

CASE PRESENTATION

A middle-aged male adult presented to the emergency department for relapse of heart failure. Echocardiography and cardiac magnetic resonance, along with the history of bilateral carpal tunnel syndrome, were suspicious for TTR-CA. The diagnosis, however, was hampered by concomitant cardiac comorbidities and conflicting results of imaging modalities. In fact bone scintigraphy was negative, as well as Congo Red Staining on myocardial tissue samples obtained by endomyocardial biopsy. Given the high clinical suspicion, immunoelectron microscopy was performed, showing TTR amyloid fibrils deposits, that confirmed the diagnosis. A genetic analysis excluded and hereditary form. The patient was then referred to a specialist center for specific treatment.

CONCLUSIONS

This is a rare case of a TTR-CA with a negative Bone Scintigraphy and Congo red staining, which demonstrated that CA is frequently misdiagnosed because of the low specific clinical manifestations and the results of imaging modalities that sometimes could be misleading, with subsequent delayed diagnosis and correct treatment.

Cardiovascular magnetic resonance in myocardial infarction with non-obstructive coronary arteries patients: A review

The diagnosis of myocardial infarction with non-obstructive coronary arteries (MINOCA) necessitates documentation of an acute myocardial infarction (AMI), non-obstructive coronary arteries, using invasive coronary angiography or coronary computed tomography angiography and no clinically overt cause for AMI. Historically patients with MINOCA represent a clinical dilemma with subsequent uncertain clinical management. Differential diagnosis is crucial to choose the best therapeutic option for ischemic and non-ischemic MINOCA patients. Cardiovascular magnetic resonance (CMR) is able to analyze cardiac structure and function simultaneously and provides tissue characterization. Moreover, CMR could identify the cause of MINOCA in nearly two-third of patients providing valuable information for clinical decision making. Finally, it allows stratification of patients with worse outcomes which resulted in therapeutic changes in almost half of the patients. In this review we discuss the features of CMR in MINOCA; from exam protocols to imaging findings.

Diagnostic value of the novel CMR parameter "myocardial transit-time" (MyoTT) for the assessment of microvascular changes in cardiac amyloidosis and hypertrophic cardiomyopathy

BACKGROUND

Coronary microvascular dysfunction (CMD) is present in various non-ischemic cardiomyopathies and in particular in those with left-ventricular hypertrophy. This study evaluated the diagnostic value of the novel cardiovascular magnetic resonance (CMR) parameter "myocardial transit-time" (MyoTT) in distinguishing cardiac amyloidosis from other hypertrophic cardiomyopathies.

METHODS

N = 20 patients with biopsy-proven cardiac amyloidosis (CA), N = 20 patients with known hypertrophic cardiomyopathy (HCM), and N = 20 control patients without relevant cardiac disease underwent dedicated CMR studies on a 1.5-T MR scanner. The CMR protocol comprised cine and late-gadolinium-enhancement (LGE) imaging as well as first-pass perfusion acquisitions at rest for MyoTT measurement. MyoTT was defined as the blood circulation time from the orifice of the coronary arteries to the pooling in the coronary sinus (CS) reflecting the transit-time of gadolinium in the myocardial microvasculature.

RESULTS

MyoTT was significantly prolonged in patients with CA compared to both groups: 14.8 ± 4.1 s in CA vs. 12.2 ± 2.5 s in HCM (p = 0.043) vs. 7.2 ± 2.6 s in controls (p < 0.001). Native T1 and extracellular volume (ECV) were significantly higher in CA compared to HCM and controls (p < 0.001). Both parameters were associated with a higher diagnostic accuracy in predicting the presence of CA compared to MyoTT: area under the curve (AUC) for native T1 = 0.93 (95% confidence interval (CI) = 0.83-1.00; p < 0.001) and AUC for ECV = 0.95 (95% CI = 0.88-1.00; p < 0.001)-compared to the AUC for MyoTT = 0.76 (95% CI = 0.60-0.92; p = 0.008). In contrast, MyoTT performed better than all other CMR parameters in differentiating HCM from controls (AUC for MyoTT = 0.93; 95% CI = 0.81-1.00; p = 0.003 vs. AUC for native T1 = 0.69; 95% CI = 0.44-0.93; p = 0.20 vs. AUC for ECV = 0.85; 95% CI = 0.66-1.00; p = 0.017).

CONCLUSION

The relative severity of CMD (measured by MyoTT) in relationship to extracellular changes (measured by native T1 and/or ECV) is more pronounced in HCM compared to CA-in spite of a higher absolute MyoTT value in CA patients. Hence, MyoTT may improve our understanding of the interplay between extracellular/intracellular and intravasal changes that occur in the myocardium during the disease course of different cardiomyopathies.

Transthyretin cardiac amyloidosis: an update on diagnosis and treatment

Transthyretin cardiac amyloidosis (ATTR‐CA) demonstrates progressive, potentially fatal, and infiltrative cardiomyopathy caused by extracellular deposition of transthyretin‐derived insoluble amyloid fibrils in the myocardium. Two distinct types of transthyretin (wild type or variant) become unstable, and misfolding forms aggregate, resulting in amyloid fibrils. ATTR‐CA, which has previously been underrecognized and considered to be rare, has been increasingly recognized as a cause of heart failure with preserved ejection fraction among elderly persons. With the advanced technology, the diagnostic tools have been improving for cardiac amyloidosis. Recently, the efficacy of several disease‐modifying agents focusing on the amyloidogenic process has been demonstrated. ATTR‐CA has been changing from incurable to treatable. Nevertheless, there are still no prognostic improvements due to diagnostic delay or misdiagnosis because of phenotypic heterogeneity and co‐morbidities. Thus, it is crucial for clinicians to be aware of this clinical entity for early diagnosis and proper treatment. In this mini‐review, we focus on recent advances in diagnosis and treatment of ATTR‐CA.

Microvascular dysfunction in infiltrative cardiomyopathies

Infiltrative heart diseases are characterized by myocardial tissue alterations leading to mechanical dysfunction which in turn develops into bi-ventricular congestive heart failure. Also the coronary microvasculature undergoes significant remodeling and dysfunction. The effects of the unbalance of the mechanical cross-talk between cardiac muscle and vessels and of the impairment of vasodilatory function can be measured non-invasively by means of positron emission tomography and cardiac magnetic resonance.

Coronary arterial vasculature in the pathophysiology of hypertrophic cardiomyopathy

Alterations in the coronary vascular system are likely associated with a mismatch between energy demand and energy supply and critical in triggering the cascade of events that leads to symptomatic hypertrophic cardiomyopathy. Targeting the early events, particularly vascular remodeling, may be a key approach to developing effective treatments. Improvement in our understanding of hypertrophic cardiomyopathy began with the results of early biophysical studies, proceeded to genetic analyses pinpointing the mutational origin, and now pertains to imaging of the metabolic and flow-related consequences of such mutations. Microvascular dysfunction has been an ongoing hot topic in the imaging of genetic cardiomyopathies marked by its histologically significant remodeling and has proven to be a powerful asset in determining prognosis for these patients as well as enlightening scientists on a potential pathophysiological cascade that may begin early during the developmental process. Here, we discuss questions that continue to remain on the mechanistic processes leading to microvascular dysfunction, its correlation to the morphological changes in the vessels, and its contribution to disease progression.

Recent advances in the noninvasive strategies of cardiac amyloidosis

The heart, like any organ in the body, is susceptible to amyloid deposition. Although more than 30 types of protein can cause amyloidosis, only two types commonly deposit in the ventricular myocardium: amyloid light chain and amyloid transthyretin. Amyloid cardiomyopathy is usually a major determinant of patient outcomes, and the diagnosis of heart involvement can be often relatively under-diagnosed, owing to nonspecific presenting symptoms and signs at a subclinical stage. The diagnosis of cardiac amyloidosis is usually performed by endomyocardial biopsy; however, the invasive nature and related high-risk complications restrict its wide use in clinical settings. Recently, with the advent of innovative techniques used for evaluating cardiac amyloidosis, noninvasive methods become increasingly important, especially in earlier diagnosis, distinguishing typing, risk prediction and response to treatment. Here, we will review recent developments in the noninvasive methods used in the assessment of cardiac amyloidosis, focused on the laboratory biomarkers and imaging modalities.

Abnormal Coronary Flow Velocity Reserve and Decreased Myocardial Contractile Reserve Are Main Factors in Relation to Physical Exercise Capacity in Cardiac Amyloidosis

BACKGROUND

The aim of the present study was to evaluate the clinical importance of echocardiographic coronary flow velocity reserve (CFVR), resting and exercise left ventricular global longitudinal strain (LVGLS), and myocardial work efficiency (MWE) in patients with cardiac amyloidosis (CA).

METHODS

The study population comprised 69 subjects: group A, 27 patients with CA confirmed by endomyocardial biopsy (CA positive); group B, 42 healthy control subjects. The amyloid phenotype in group A was as follows: patients with wild-type transthyretin-related amyloidosis (n = 10), carriers of the Danish familial transthyretin amyloidosis mutation with cardiac involvement (n = 5), and patients with amyloid light chain amyloidosis with cardiac involvement (n = 12). All subjects underwent comprehensive echocardiographic evaluation during rest and during symptom-limited, semisupine exercise testing. Furthermore, CFVR was assessed using Doppler echocardiography.

RESULTS

Patients with CA had significantly lower CFVR (1.7 ± 0.6 vs 3.9 ± 0.8, P < .0001), MWE (1.9 ± 1.0 vs 3.0 ± 0.7, P < .0001), and LVGLS magnitude (11% [10%-14%] vs 20% [18%-21%], P < .0001) than control subjects. Patients with CA showed severely reduced deformation and efficiency reserve compared with control subjects (ΔLVGLS 0.9 ± 2.8% vs 5.6 ± 2.3%, P < .0001; ΔMWE 2.5 ± 2.8 vs 8.8 ± 2.6, P < .0001). In patients with CA, a strong relation was seen between physical capacity by the metabolic equivalent of tasks test and CFVR (r = 0.55, P < .01), peak exercise LVGLS (r = 0.64, P < .0001), and peak exercise MWE (r = 0.60, P < .01).

CONCLUSIONS

Patients with CA had a profound lack of CFVR and longitudinal myocardial deformation reserve compared with healthy control subjects. Both parameters were significantly associated with exercise capacity and may prove useful for evaluating cardiac performance in patients with CA.

Transthyretin Cardiac Amyloidosis

PURPOSE OF REVIEW

Transthyretin (TTR)-related cardiac amyloidosis is a progressive infiltrative cardiomyopathy that mimics hypertensive, hypertrophic heart disease and may go undiagnosed. Transthyretin-derived amyloidosis accounts for 18% of all cases of cardiac amyloidosis. Thus, the study's purpose is to provide a comprehensive review of transthyretin cardiac amyloidosis.

RECENT FINDINGS

Wild-type transthyretin (ATTRwt) protein causes cardiac amyloidosis sporadically, with 25 to 36% of the population older than 80 years of age are at risk to develop a slowly progressive, infiltrative amyloid cardiomyopathy secondary to ATTRwt. In contrast, hereditary amyloidosis (ATTRm) is an autosomal dominant inherited disease associated with more than 100 point mutations in the transthyretin gene and has a tendency to affect the heart and nervous system. Up to 4% of African-Americans carry the Val122Ile mutation in the transthyretin gene, the most prevalent cause of hereditary cardiac amyloidosis in the USA. Identifying transthyretin cardiac amyloidosis requires increased awareness of the prevalence, signs and symptoms, and diagnostic tools available for discrimination of this progressive form of cardiomyopathy associated with left ventricular hypertrophy. While there are no FDA-approved medical treatments, investigation is underway on agents to reduce circulating mutated transthyretin.

Contribution of human smooth muscle cells to amyloid angiopathy in AL (light-chain) amyloidosis

OBJECTIVE

Amyloid light-chain (AL) amyloidosis is a disease process that often compromises the peripheral vascular system and leads to systemic end-organ dysfunction. Although amyloid formation in vessel walls is a multifaceted process, the assembly of the native light chains (LCs) into amyloid fibrils is central to its pathogenesis. Recent evidence suggests that endocytosis and endolysosomal processing of immunoglobin LCs by host cells is essential to the formation of amyloid fibrils that are deposited in at least some tissues. The aim of this study was to elucidate the role of vascular smooth muscle in amyloid angiopathy.

METHODS

Human coronary artery smooth muscle cells (SMCs) were grown on coverslips, four chamber glass slides, and growth factor-reduced Matrigel matrix in the presence of 10 µg/ml of ALs (λ and κ isotypes), nonamyloidogenic LCs, and culture medium (negative control) for 48 and 72 hours. Thereafter, a detailed light microscopic, immunohistochemical, and ultrastructural evaluation was conducted to verify amyloid deposition and characterize the role of SMCs in the formation of amyloid deposits in the various experimental conditions.

RESULTS

Amyloid deposits were detected extracellulary as early as 48 hours after exposure of vascular smooth muscle cells (VSMCs) to AL-LCs (amyloidogenic light chains) as confirmed by affinity to Congo red dye, thioflavin T fluorescence, and transmission electron microscopy. No amyloid was present in the cultures of SMCs treated with medium alone or nonamyloidogenic LCs. SMCs associated with amyloid deposits exhibited CD68, lysosome-associated membrane protein 1-1, and intracellular lambda light chain expression and only focal smooth muscle actin and muscle-specific actin positivity. Electron microscopy revealed these cells to have an expanded mature lysosomal compartment closely associated with deposits of newly formed amyloid fibrils.

CONCLUSIONS

The interaction of amyloidogenic LCs with VSMCs is necessary for the formation of amyloid fibrils that are deposited in peripheral vessels. VSMCs participate in the formation of amyloid by the intracellular processing of AL-LCs, which is possible due to their transformation from a smooth muscle to a macrophage phenotype. The formation of amyloid fibrils occurs in the mature lysosomal compartment of transformed cells. The amyloid that is formed is then extruded into the extracellular matrix.

Role of PET to evaluate coronary microvascular dysfunction in non-ischemic cardiomyopathies

Coronary microvascular dysfunction (CMD) can result from structural and functional abnormalities at the intramural and small coronary vessel level affecting coronary blood flow autoregulation and consequently leading to impaired coronary flow reserve. CMD often co-exists with epicardial coronary artery disease but is also commonly seen in patients with various forms of heart disease, including dilated, hypertrophic, and infiltrative cardiomyopathies. CMD can go unnoticed without any symptoms, or manifest as angina, and/or dyspnea, and contribute to the development of heart failure, and even sudden death especially when co-existing with myocardial fibrosis. However, whether CMD in non-ischemic cardiomyopathy is a cause or an effect of the underlying cardiomyopathic process, or whether it can be potentially modifiable with specific therapies, remains incompletely understood.

Radiologic-Pathologic Correlation of Primary and Secondary Cardiomyopathies: MR Imaging and Histopathologic Findings in Hearts from Autopsy and Transplantation

RSNA, 2017.

Monosialoganglioside-Containing Nanoliposomes Restore Endothelial Function Impaired by AL Amyloidosis Light Chain Proteins

BACKGROUND

Light chain amyloidosis (AL) is associated with high mortality, especially in patients with advanced cardiovascular involvement. It is caused by toxicity of misfolded light chain proteins (LC) in vascular, cardiac, and other tissues. There is no treatment to reverse LC tissue toxicity. We tested the hypothesis that nanoliposomes composed of monosialoganglioside, phosphatidylcholine, and cholesterol (GM1 ganglioside-containing nanoliposomes [NLGM1]) can protect against LC-induced human microvascular dysfunction and assess mechanisms behind the protective effect.

METHODS AND RESULTS

The dilator responses of ex vivo abdominal adipose arterioles from human participants without AL to acetylcholine and papaverine were measured before and after exposure to LC (20 μg/mL) with or without NLGM1 (1:10 ratio for LC:NLGM1 mass). Human umbilical vein endothelial cells were exposed for 18 to 20 hours to vehicle, LC with or without NLGM1, or NLGM1 and compared for oxidative and nitrative stress response and cellular viability. LC impaired arteriole dilator response to acetylcholine, which was restored by co-treatment with NLGM1. LC decreased endothelial cell nitric oxide production and cell viability while increasing superoxide and peroxynitrite; these adverse effects were reversed by NLGM1. NLGM1 increased endothelial cell protein expression of antioxidant enzymes heme oxygenase 1 and NAD(P)H quinone dehydrogenase 1 and increased nuclear factor, erythroid 2 like 2 (Nrf-2) protein. Nrf-2 gene knockdown reduced antioxidant stress response and reversed the protective effects of NLGM1.

CONCLUSIONS

NLGM1 protects against LC-induced human microvascular endothelial dysfunction through increased nitric oxide bioavailability and reduced oxidative and nitrative stress mediated by Nrf-2-dependent antioxidant stress response. These findings point to a potential novel therapeutic approach for light chain amyloidosis.

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.

Abnormal Myocardial Blood Flow Reserve Observed in Cardiac Amyloidosis

We performed real-time myocardial contrast echocardiography on a patient with cardiac amyloidosis and previous normal coronary angiography presenting with atypical chest pain to assess myocardial blood flow reserve (MBFR). Myocardial contrast echocardiography was performed and flash microbubble destruction and replenishment analysis was used to calculate myocardial blood flow. Dipyridamole was used to achieve hyperemia. MBFR was derived from the ratio of peak myocardial blood flow at hyperemia and rest. The results show a marked reduction in MBFR in our patient. Previous reports of luminal obstruction of intramyocardial rather than epicardial vessels by amyloid deposition may be causing microvascular dysfunction.

Cardiac amyloidosis presenting as recurrent acute coronary syndrome with unobstructed coronary arteries: Case report

Amyloidosis is a systemic disorder characterized by the deposition of mis-folded protein molecules within various organs. Cardiac involvement may be the presenting feature of this condition or may be identified incidentally during investigation for amyloidosis affecting other organs. The presence and severity of cardiac involvement varies with the type of amyloidosis. Irrespective of the subtype, patients with cardiac amyloidosis usually present with symptoms of heart failure with echocardiography showing features of restrictive cardiomyopathy. The usual cardiac symptoms noted in patients with amyloidosis include dyspnea, peripheral edema, and palpitations secondary to arrhythmias.(1) Chest pain secondary to myocardial ischemia is an unusual presentation of cardiac amyloidosis, and is attributed to the deposition of protein molecules in the coronary microvasculature. We describe the case of a patient who presented with recurrent cardiac ischemia secondary to amyloidosis.

Infiltrative Cardiomyopathies

Infiltrative cardiomyopathies can result from a wide spectrum of both inherited and acquired conditions with varying systemic manifestations. They portend an adverse prognosis, with only a few exceptions (ie, glycogen storage disease), where early diagnosis can result in potentially curative treatment. The extent of cardiac abnormalities varies based on the degree of infiltration and results in increased ventricular wall thickness, chamber dilatation, and disruption of the conduction system. These changes often lead to the development of heart failure, atrioventricular (AV) block, and ventricular arrhythmia. Because these diseases are relatively rare, a high degree of clinical suspicion is important for diagnosis. Electrocardiography and echocardiography are helpful, but advanced techniques including cardiac magnetic resonance (CMR) and nuclear imaging are increasingly preferred. Treatment is dependent on the etiology and extent of the disease and involves medications, device therapy, and, in some cases, organ transplantation. Cardiac amyloid is the archetype of the infiltrative cardiomyopathies and is discussed in great detail in this review.

Late gadolinium enhancement in cardiac amyloidosis: attributable both to interstitial amyloid deposition and subendocardial fibrosis caused by ischemia

Gadolinium contrast agents used for late gadolinium enhancement (LGE) distribute in the extracellular space. Global diffuse myocardial LGE pronounced in the subendocardial layers is common in cardiac amyloidosis. However, the pathophysiological basis of these findings has not been sufficiently explained. A 64-year-old man was admitted to our hospital with leg edema and nocturnal dyspnea. Bence Jones protein was positive in the urine, and an endomyocardial and skin biopsy showed light-chain (AL) amyloidosis. He died of ventricular fibrillation 3 months later. 9 days before death, the patient was examined by cardiac magnetic resonance (CMR) imaging on a 3-T system. We acquired LGE data at 2, 5, 10, and 20 min after the injection of gadolinium contrast agents, with a fixed inversion time of 350 ms. Myocardial LGE developed sequentially. The myocardium was diffusely enhanced at 2 min, except for the subendocardium, but LGE had extended to almost the entire left ventricle at 5 min and predominantly localized to the subendocardial region at 10 and 20 min. An autopsy revealed massive and diffused amyloid deposits in perimyocytes throughout the myocardium. Old and recent ischemic findings, such as replacement fibrosis and coagulative myocyte necrosis, were evident in the subendocardium. In the intramural coronary arteries, mild amyloid deposits were present within the subepicardial to the mid layer of the left ventricle, but no stenotic lesions were evident. However, capillaries were obstructed by amyloid deposits in the subendocardium. In conclusion, the late phase of dynamic LGE (at 10 and 20 min) visualized in the subendocardium corresponded to the interstitial amyloid deposition and subendocardial fibrosis caused by ischemia in our patient.

Left ventricular amyloid deposition in patients with heart failure and preserved ejection fraction

OBJECTIVES

This study sought to determine the frequency of left ventricular amyloid in heart failure with preserved ejection fraction (HFpEF).

BACKGROUND

Left ventricular amyloid deposition can cause diastolic dysfunction and HFpEF.

METHODS

Autopsy of left ventricular specimens from patients with antemortem diagnosis of HFpEF without clinically apparent amyloid (n = 109) and from control subjects (n = 131) were screened with sulfated Alcian blue and subsequent Congo red staining with microdissection for mass spectrometry-based proteomics to determine amyloid type. Fibrosis was assessed with quantitative whole-field digital microscopy.

RESULTS

The presence of wild-type transthyretin (wtTTR) amyloid was associated with age at death and male sex, but the age- and sex-adjusted prevalence of wtTTR amyloid was higher in HFpEF patients than in control subjects (odds ratio: 3.8, 95% confidence interval: 1.5 to 11.3; p = 0.03). Among HFpEF patients, moderate or severe interstitial wtTTR deposition, consistent with senile systemic amyloidosis as the primary etiology of HFpEF, was present in 5 (5%) patients (80% men), with mild interstitial and/or variable severity of intramural coronary vascular deposition in 13 (12%) patients. While, wtTTR deposition was often mild, adjusting for age and presence of HFpEF, wtTTR amyloid was associated with more fibrosis (p = 0.005) and lower age, sex, and body size-adjusted heart weight (p = 0.04).

CONCLUSIONS

Given the age- and sex-independent association of HFpEF and wtTTR deposition and an emerging understanding of the pathophysiology of the amyloidoses, the current findings support further investigation of the role of wtTTR in the pathophysiology of HFpEF.

Cardiac magnetic resonance imaging of systemic amyloidosis patients with normal left ventricular ejection fraction: An initial study

Objective: The purpose of this study was to find whether Cardiac Magnetic Resonance (CMR) could assess the myocardial interstitium in patients suffering from systemic amyloidosis with normal left ventricular ejection fraction.

Methods: Twenty Six patients in whom systemic amyloidosis was confirmed by kidney biopsy were investigated. Five patients with normal left ventricular ejection fraction were selected. The heart function of the patients was diagnosed by two-dimensional transthoracic echocardiography. The main MR sequences include an inversion recovery prepared echo planar imaging perfusion sequence, inversion recovery TrueFISP sequence (delayed enhancement) and TrueFISP cine sequence for heart function measurement (including ejection fraction (EF), end diastolic volume (EDV), end systolic volume (ESV), stroke volume (SV) and cardiac output (CO)).

Results: Perfusion defects were seen in three patients. In these patients, myocardial enhancement was visible on late gadolinium enhancement images. The enhancement pattern was diffuse in three patients and focal in two patients. Heart dysfunction was mild, as follows: EF normal (range, 56-75%; mean, 69.4%), ESV normal (range, 15.7-30.0; mean, 23.0), EDV decreased (range, 42.1-96.6; mean, 72.7), SV decreased (range, 23.7-68.6; mean, 49.6) and CO normal (range, 2.6-5.9; mean, 3.9). Hematoxylin and eosin stain and Congo red stain demonstrated typical amyloid deposits. Amyloidosis was classified as amyloid light chain by kappa and lambda stain.

Conclusions: Cardiac Magnetic Resonance could detect abnormal myocardial interstitium in systemic amyloidosis patients with normal left ventricular ejection fraction.

Amyloid formation in light chain amyloidosis

Light chain amyloidosis is one of the unique examples within amyloid diseases where the amyloidogenic precursor is a protein that escapes the quality control machinery and is secreted from the cells to be circulated in the bloodstream. The immunoglobulin light chains are produced by an abnormally proliferative monoclonal population of plasma cells that under normal conditions produce immunoglobulin molecules such as IgG, IgM or IgA. Once the light chains are in circulation, the proteins misfold and deposit as amyloid fibrils in numerous tissues and organs, causing organ failure and death. While there is a correlation between the thermodynamic stability of the protein and the kinetics of amyloid formation, we have recently found that this correlation applies within a thermodynamic range, and it is only a helpful correlation when comparing mutants from the same protein. Light chain amyloidosis poses unique challenges because each patient has a unique protein sequence as a result of the selection of a germline gene and the incorporation of somatic mutations. The exact location of the misfolding process is unknown as well as the full characterization of all of the toxic species populated during the amyloid formation process in light chain amyloidosis.

Cardiac injury after 10 gy total body irradiation: indirect role of effects on abdominal organs

The objective of this study was to determine whether radiation-induced injury to the heart after 10 Gy total body irradiation (TBI) is direct or indirect. Young male WAG/RijCmcr rats received a 10 Gy single dose using TBI, upper hemi-body (UHB) irradiation, lower hemi-body (LHB) irradiation, TBI with the kidneys shielded or LHB irradiation with the intestines shielded. Age-matched, sham-irradiated rats served as controls. The lipid profile, kidney injury, heart and liver morphology and cardiac function were determined up to 120 days after irradiation. LHB, but not UHB irradiation, increased the risk factors for cardiac disease as well as the occurrence of cardiac and kidney injury in a way that was quantitatively and qualitatively similar to that observed after TBI. Shielding of the kidneys prevented the increases in risk factors for cardiac disease. Shielding of the intestines did not prevent the increases in risk factors for cardiac disease. There was no histological evidence of liver injury 120 days after irradiation. Injury to the heart from irradiation appears to be indirect, supporting the notion that injury to abdominal organs, principally the kidneys, is responsible for the increased risk factors for and the occurrence of cardiac disease after TBI and LHB irradiation.