Diagnosis of cardiac amyloidosis based on the myocardial velocity profile in the hypertrophied left ventricular wall

Multiparametric Echocardiography Scores for the Diagnosis of Cardiac Amyloidosis

OBJECTIVES

This study aimed to investigate the accuracy of a broad range of echocardiographic variables to develop multiparametric scores to diagnose CA in patients with proven light chain (AL) amyloidosis or those with increased heart wall thickness who had amyloid was suspected. We also aimed to further characterize the structural and functional changes associated with amyloid infiltration.

BACKGROUND

Cardiac amyloidosis (CA) is a serious but increasingly treatable cause of heart failure. Diagnosis is challenging and frequently unclear at echocardiography, which remains the most often used imaging tool.

METHODS

We studied 1,187 consecutive patients evaluated at 3 referral centers for CA and analyzed morphological, functional, and strain-derived echocardiogram parameters with the aim of developing a score-based diagnostic algorithm. Cardiac amyloid burden was quantified by using extracellular volume measurements at cardiac magnetic resonance.

RESULTS

A total of 332 patients were diagnosed with AL amyloidosis and 339 patients with transthyretin CA. Concentric remodeling and strain-derived parameters displayed the best diagnostic performance. A multivariable logistic regression model incorporating relative wall thickness, E wave/e' wave ratio, longitudinal strain, and tricuspid annular plane systolic excursion had the greatest diagnostic performance in AL amyloidosis (area under the curve: 0.90; 95% confidence interval: 0.87 to 0.92), whereas the addition of septal apical-to-base ratio yielded the best diagnostic accuracy in the increased heart wall thickness group (area under the curve: 0.80; 95% confidence interval: 0.85 to 0.90).

CONCLUSIONS

Specific functional and structural parameters characterize different burdens of CA deposition with different diagnostic performances and enable the definition of 2 scores that are sensitive and specific tools with which diagnose or exclude CA.

The role of echocardiography in the non-invasive diagnosis of cardiac amyloidosis

INTRODUCTION

The diagnosis of cardiac amyloidosis (CA) is usually performed by endomyocardial biopsy; however, possible sampling errors and procedural risks such as cardiac tamponade, malignant arrhythmias and bleeding risk, limit its use. Therefore, a non-invasive diagnostic method appears to be necessary.

MATERIALS AND METHODS

Echocardiography plays an important role in this need. Conventional two-dimensional echocardiography appears able to detect some specific and distinguishing signs of cardiac amyloid infiltration.

RESULTS AND CONCLUSIONS

Of these, thickened right and left ventricular (LV) myocardium, normal or small LV cavity size in contrast to enlarged biatrial cavities, diffuse hyper-refractile 'granular sparkling' appearance and 'mismatch' ECG/ECHO are the most specific findings. The magnitude of cyclic variation recorded with integrated backscatter reflects structural changes in the myocardium. In patients with CA, this magnitude is reduced because myocardial amyloid infiltration is characterized by a reduction of number of "contractile" fibers. Other informations concerning LV dysfunction CA-related can be obtained by Tei index. Finally, new echocardiographic imaging modalities, such as tissue Doppler, Doppler-based strain, speckle tracking imaging and three-dimensional echocardiography, can provide some findings regarding the preclinical stages of LV dysfunction when other echocardiographic measurements are showing normal; however, these are unable to provide a non-invasive diagnosis of cardiac amyloidosis.

Differentiation of infiltrative cardiomyopathy from hypertrophic cardiomyopathy using high-sensitivity cardiac troponin T: a case-control study

Background

Because infiltrative cardiomyopathy and hypertrophic cardiomyopathy (HCM) share clinical and hemodynamic features of left ventricular (LV) hypertrophy and abnormal diastolic function, it is often difficult to distinguish these entities.

Methods

We investigated the potential role of high-sensitivity cardiac troponin T (hs-cTnT) for differentiation of infiltrative cardiomyopathy from HCM.

Results

The study group consisted of 46 consecutive patients with infiltrative cardiomyopathies or HCM in whom sarcomere protein gene mutations were identified at Kochi Medical School Hospital; of these, there were 11 patients with infiltrative cardiomyopathy (cardiac amyloidosis in 8 patients and Fabry disease in 3 patients) and 35 HCM patients. Serum hs-cTnT level was significantly higher in patients who had infiltrative cardiomyopathy than in those who had HCM (0.083 ± 0.057 ng/ml versus 0.027 ± 0.034 ng/ml, p < 0.001), whereas brain natriuretic peptide levels did not differ between the two groups. In two age-matched the 2 cohorts (patients evaluated at > 40 years at age), hs-cTnT level, maximum LV wall thickness, posterior wall thickness, peak early (E) transmitral filling velocity, peak early diastolic (Ea) velocity of tissue Doppler imaging at the lateral corner and E/Ea ratios at both the septal and lateral corners were significantly different between the two groups. As for diagnostic accuracy to differentiate the two groups by using receiver operating characteristic analysis, hs-cTnT was the highest value of area under the curve (0.939) and E/Ea (lateral) was second highest value (0.914).

Conclusions

Serum hs-cTnT is a helpful diagnostic indicator for accurate differentiation between infiltrative cardiomyopathy and HCM.

Echocardiographic assessment of the cardiac amyloidoses

Cardiac amyloidosis is a cardiomyopathy characterized by increased left ventricular (LV) wall thickness and normal or decreased LV cavity size. Congestive heart failure in cardiac amyloidosis is generally considered a predominantly diastolic phenomenon, with systolic dysfunction only occurring in late-stage disease. Echocardiography is a noninvasive, reproducible method of assessing cardiac features and function in cardiac amyloidosis, and some echocardiographic indices are prognostic for the amyloidoses, with M-mode and 2-dimensional echocardiography able to detect increased LV wall thickness. Moreover, Doppler flow measurements can incrementally assess diastolic LV dysfunction, which is characteristic of cardiac amyloidosis, and provide important prognostic information. Additionally, tissue Doppler imaging can detect subtle changes in both systolic and diastolic LV function, which cannot be detected by Doppler flow measurements, and LV longitudinal strain assessed by color tissue Doppler and speckle tracking echocardiography can provide more accurate LV functional and prognostic information than tissue Doppler imaging. This review describes the advances in echocardiography and its crucial role in the diagnosis and management of cardiac amyloidosis.

Systemic amyloidoses: what an internist should know

Systemic amyloidoses are rare, complex diseases caused by misfolding of autologous proteins. Although these diseases are fatal, effective treatments exist that can alter their natural history, provided that they are started before irreversible organ damage has occurred. The cornerstones of the management of systemic amyloidoses are early diagnosis, accurate typing, appropriate risk-adapted therapy, tight follow-up, and effective supportive treatment. Internists play a key role in suspecting the disease, thus allowing early diagnosis, starting the diagnostic workup and selecting patients that should be referred to specialized centers, judiciously titrating supportive measures, and following patients throughout the course of the disease. Here we review the pathogenesis, diagnosis and treatment of the most common forms of systemic amyloidoses.

The challenge of systemic immunoglobulin light-chain amyloidosis (Al)

The cardiac involvement and associated mortality that occur in systemic AL amyloidosis remain among the most challenging aspects of the systemic amyloid-related diseases. Monoclonal immunoglobulin light chains produced by a clone of plasma cells are usually the cause of symptoms and organ dysfunction via both poorly understood toxic effects of misfolded species and accumulation of interstitial amyloid fibrils in key viscera. Treatment is aimed at eliminating the clonal cells in order to eliminate toxic light chain production. Recent advances in therapy have helped many patients with AL achieve complete hematologic responses and significant reversal of organ damage but these benefits do not extend to that 10-15 % who present with advanced cardiac involvement. Even with cardiac transplant followed by effective therapy such as stem cell transplant, outcomes for these patients remain promising at best.

Stiff heart syndrome

Isolated cardiac amyloidosis, or "Stiff Heart Syndrome," is a rare manifestation of amyloidosis. Some degree of cardiac amyloid deposition is common in elderly patients, as reported in prior post-mortem studies; however, isolated cardiac involvement with predominantly cardiac symptoms and no evidence of systemic disease is a rare presentation. Establishing the correct diagnosis, even with the use of extensive testing including amyloid typing, understanding the clinical significance, and management can be challenging in such cases.

Detection of increased left ventricular filling pressure by pulsed tissue Doppler in cardiac amyloidosis

OBJECTIVE

The aim of this study was to evaluate the incremental diagnostic role of tissue Doppler in primary cardiac amyloidosis (CA).

METHODS

Eleven patients with CA at diagnosis and 11 healthy controls, matched for sex and age, underwent standard Doppler echocardiography and pulsed tissue Doppler of the left ventricular (LV) lateral annulus, in the apical four-chamber view. The ratio of early transmitral flow velocity to early diastolic mitral annular velocity (E/E(m) ratio) was derived as an index of LV filling pressure.

RESULTS

The two groups were comparable for body mass index, blood pressure, heart rate and standard Doppler diastolic measurements. Patients with CA had a significantly higher sum of wall thickness (SWT) and LV mass, a lower E(m) peak velocity (P < 0.002) and a higher E/E(m) ratio (P < 0.001) than controls. By dividing CA patients according to the transmitral E/A ratio, patients with an E/A ratio < 1 (abnormal relaxation) (n = 5) and patients with an E/A ratio > 1 (likely pseudonormal/restrictive pattern) (n = 6) did not show any difference in the E/E(m) ratio (14.5 + or - 7.1 vs. 15.1 + or - 6.4, P = NS). In the overall population, the E/E(m) ratio was related to SWT (r = 0.84, P < 0.0001) and LV mass index (r = 0.72, P < 0.0001). After adjusting for age and heart rate by separate multivariate models, SWT (beta = 0.78, P < 0.0001; cumulative r(2) = 0.63, SE = 3.38, P < 0.0001) and LV mass index (beta = 0.71, P < 0.0001; cumulative r(2) = 0.53, SE = 3.80, P < 0.002) were both independently associated with the E/E(m) ratio.

CONCLUSIONS

Pulsed tissue Doppler is able to detect early myocardial diastolic impairment in CA. The E/E(m) ratio is very useful in diagnosing increased LV filling pressure, regardless of the transmitral pattern, and may, therefore, be helpful in the clinical management of these patients.

Cardiac amyloidosis in a patient with multiple myeloma: a case report and review of literature

We report a case of a 52-year-old man with multiple myeloma and rapidly progressive heart failure who died unexpectedly from a probable arrhythmia. Postmortem examination revealed infiltrative amyloid cardiomyopathy, a rare cause of predominantly diastolic myocardial disease. Cardiac amyloidosis should be considered in any patient presenting with congestive heart failure, preserved systolic function, and a discrepancy between a low QRS voltage on electrocardiography and an apparent left ventricular hypertrophy on sonogram. The pattern of left ventricular diastolic dysfunction changes during the course of amyloidosis and the classically described restrictive physiology occurs only in advanced stages of the disease.

Biochemical characterisation of amyloid by endomyocardial biopsy

Cardiomyopathy is a major cause of death in patients with systemic amyloidosis. There are several forms of systemic amyloidosis which cause cardiomyopathy and determination of the exact type of amyloid in each affected patient is essential for treatment and determination of prognosis. In this study, we tested the feasibility of determining the type of amyloidosis by biochemical analysis of endomyocardial biopsies. Right ventricular endomyocardial biopsies were obtained from 10 patients with restrictive cardiomyopathy. Three patients had monoclonal protein demonstrated in serum or urine and all three had bone marrow findings consistent with monoclonal gammopathy. Seven patients had isolated cardiomyopathy without evidence of monoclonal gammopathy. A portion of each myocardial biopsy was submitted for histologic evaluation and all demonstrated amyloid by Congo red staining. Each biopsy was analysed biochemically by isolation of amyloid fibrils and the protein characterised by amino acid sequence analysis. Four amyloid isolates were characterised as immunoglobulin light chain proteins. Two specimens obtained from patients with transthyretin (TTR) DNA mutations contained TTR peptides proving the hereditary nature of the disease. Biopsies from four patients without a TTR mutation contained TTR and were consistent with the diagnosis of senile cardiac amyloidosis (SCA). All endomyocardial biopsy specimens that were analysed had sufficient amyloid fibril subunit protein to allow characterisation by amino acid sequence analysis. This methodology is particularly useful in differentiating SCA with TTR amyloid fibrils from immunoglobulin light chain amyloidosis which also occurs in the elderly age group.

Currently available technology for echocardiographic assessment of left ventricular function

New ultrasound technology is mainly represented by tissue Doppler (TD), which allows the quantitative analysis of myocardial function and includes two modalies: pulsed-wave TD and color TD. Strain rate imaging (SRI) is an implementation of color TD. Pulsed-wave TD, performed and analyzed in real time, instantaneously measures myocardial velocities. Color TD, performed offline on digitally stored images, allows the quantification of mean myocardial velocities. The advantage of color TD compared with pulsed TD is the ability to simultaneously analyze multiple myocardial segments. The limit of both these methodologies consists of the myocardial velocity dependence by the base-apex myocardial gradient. SRI measures the rate and percentage of myocardial wall deformation. From digitally recorded color TD cine loops containing velocity data from the entire myocardium, SRI can be derived from regional Doppler velocity gradients. Strain rate is relatively load dependent, and, therefore, can be considered a strong index of myocardial contractility. Due to these favorable characteristics, SRI may potentially overcome the limitations of color TD, discriminating between active and merely passive wall motion. A novel technique is the implementation of 2D SRI, which is not angle dependent, and therefore potentially more feasible and reliable.

Risk stratification in cardiac amyloidosis: novel approaches

Amyloidosis is a term for diseases with extracellular deposition of insoluble beta-fibrillar proteins in different organs. The heart is primarily involved in more than half of patients with immunoglobulin light-chain amyloidosis or hereditary amyloidosis and associated with poor prognosis. Different traditional diagnostic tools that have been described for risk stratification lack of sufficient sensitivity and specificity for patient survival. Until November 2004 in 50 consecutive patients with light chain amyloidosis and 15 patients with hereditary amyloidosis electrocardiography, echocardiography, Holter monitoring, cardiopulmonary exercise test, lung function testing, tilt-test, and laboratory investigations have been performed at our department. Cardiac amyloidosis was found in 32 patients. Interventricular septum (14.3+/-0.5 mm vs. 12.3+/-0.7 mm, P<0.05), plasma NT-proBNP (7154+/-2122 ng/l vs. 380+/-113 ng/l; P<0.01), cardiac Troponin T (0.105+/-0.030 vs. 0.019+/-0.010 microg/l; P<0.05) were increased in patients with cardiac amyloidosis as compared to patients light chain amyloidosis but no cardiac involvement. Maximal inspiratory (Pimax) and expiratory (Pemax) mouth pressure were decreased with CA compared to controls. Correlation of NT-proBNP and interventricular septum thickness (r=0.53, P=0.029) as well as and Pimax (r=0.72, P<0.01) or Pemax (r=0.69; P<0.01) was noticed. A correlation of grade of arrhythmias in Holter monitoring and syncopes was not observed. Cardiac involvement of amyloid disease carries a poor prognosis and is not well characterized by classic heart failure determinants. Heart transplantation based on novel risk markers including NT-proBNP might be a suitable therapeutic approach for patients with manifest cardiac amyloidosis, but will require alternative patient selection and listing criteria.

Amyloidosis: diagnosis and management

Amyloidosis is a rare plasma cell proliferative disorder. The annual incidence in Olmsted County, Minnesota, is 8 in 1,000,000 patients. This is a difficult disorder to diagnose, because the symptoms at presentation are vague and include dyspnea, paresthesias, edema, weight loss, and fatigue. The clinical syndromes at the time of presentation include nephrotic-range proteinuria with or without renal failure, cardiomyopathy, "atypical multiple myeloma," hepatomegaly, and autonomic or peripheral neuropathy. The serum immunoglobulin free light chain assay has been an important step forward in classifying systemic amyloidosis as an immunoglobulin light chain form and in monitoring therapy. Recently, the importance of serum cardiac biomarkers in assessing outcome has been recognized. New therapies developed over the past 5 years include high-dose chemotherapy with stem cell reconstitution, combinations of alkylating agents with dexamethasone, and, most recently, thalidomide.

Amyloidosis

Amyloidosis is an uncommon plasma-cell dyscrasia with an incidence of eight patients per million per year. It is often difficult to recognize because of the myriad symptoms and vague nature of the clinical presentation. Symptoms include fatigue, dyspnea, edema, paresthesias, and weight loss. Clinical syndromes at presentation include nephrotic-range proteinuria with or without renal insufficiency, cardiomyopathy, hepatomegaly, symptomatic peripheral neuropathy, and autonomic failure. Recent advances have occurred in evaluation of patients by using the free light chain assay and new prognostic assessments with cardiac biomarkers. Newly developed therapeutic strategies, involving high-dose and intermediate-dose chemotherapy, have evolved in the last 3 years. This paper reviews a diagnostic pathway clinicians can use to diagnose the disorder, assess a patient's prognosis, and logically plan a therapeutic strategy.

Detection of early systolic dysfunction with strain rate imaging in a patient with light chain cardiomyopathy

Congestive heart failure (CHF) in cardiac amyloidosis has been attributed to the development of diastolic dysfunction, because severe CHF symptoms have been observed despite a normal or only mildly reduced LV ejection fraction (EF). An early impairment of longitudinal systolic function has been described by means of tissue Doppler-derived myocardial deformation imaging ('strain rate imaging', SRI). Our patient presented with signs of CHF and significantly increased brain-natriuretic peptide (BNP) levels. Conventional measures of systolic contractile function were within the normal range and mitral inflow Doppler showed only moderate diastolic dysfunction. Histopathological examination by endomyocardial biopsy revealed interstitial deposition of amyloid fibers. Quantitative assessment of myocardial velocities (TDI) and deformation properties (Strain) from the apical view demonstrated a significant impairement of systolic longitudinal myocardial function. In patients with isolated diastolic dysfunction detected by conventional Doppler echocardiography, the quantitative assessment of myocardial strain and strain rate can be helpful in the early detection of systolic dysfunction.

Tissue Doppler imaging in the evaluation of patients with cardiac amyloidosis

PURPOSE OF REVIEW

Although two-dimensional, M-mode, and Doppler echocardiography have played a major role in the assessment of amyloid deposition in the heart, diagnosis of cardiac amyloidosis (CA) based on these conventional techniques is often only possible once the disease is in a relatively advanced stage. To optimize survival, early diagnosis and institution of therapy are essential. Recently, tissue Doppler imaging (TDI) and myocardial strain rate (SR) have emerged as important clinical tools in the assessment of CA.

RECENT FINDINGS

Tissue Doppler imaging-derived modalities including TDI velocities, strain, and SR are currently being used in the early diagnosis and evaluation of patients with CA. Although these new indices have been examined in relatively few patients, findings suggest an important and expanding role of TDI in amyloid infiltration of the heart.

SUMMARY

This review summarizes the recent literature addressing the role of TDI velocities, strain, and SR in the diagnosis and assessment of CA.