Do troponin and B-natriuretic peptide detect cardiomyopathy in transthyretin amyloidosis?

High-Sensitivity Cardiac Troponin T to Exclude Cardiac Involvement in TTR Variant Carriers and ATTRv Amyloidosis Patients

(1) Background: Individuals carrying a pathogenic transthyretin gene variant (TTRv) are at high risk for developing hereditary transthyretin (ATTRv) amyloidosis and are routinely screened for the development of cardiomyopathy (ATTRv-CM). This study aims to evaluate whether the cardiac biomarkers N-terminal pro B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) can be used to rule out ATTRv-CM. (2) Methods: In this retrospective case-control study, data from 46 ATTRv-CM patients and 101 TTRv carriers and ATTRv amyloidosis patients without cardiomyopathy were included. Binary logistic regression models were used to assess the ability of NT-proBNP and hs-cTnT to predict the diagnosis of ATTRv-CM. An optimal cutoff for the relevant biomarker(s) was determined based on a sensitivity of ≥99% and the highest possible percentage of additional tests avoided (%ATA) in the index dataset. (3) Results: Hs-cTnT demonstrated the highest predictive capabilities for ATTRv-CM. The addition of NT-proBNP did not improve the predictive model. A hs-cTnT cutoff of <6 ng/L resulted in a 97% sensitivity and a negative predictive value of 95% with a %ATA of 30% in the validation dataset. (4) Conclusion: In conclusion, hs-cTnT is a useful biomarker for excluding cardiac involvement in TTRv carriers and ATTRv amyloidosis patients and it has the potential to prevent unnecessary diagnostic procedures.

Cardiac amyloidosis: a review of the literature

Cardiac amyloidosis is a rare disease associated with severe morbidity and mortality. There are three main types of amyloidosis associated with cardiac involvement: light chain (AL), familial or senile (ATTR) and secondary amyloidosis (AA). Cardiac amyloidosis often results in heart failure with preserved left ventricular ejection fraction, may display echocardiographic features of restrictive cardiomyopathy associated with left ventricular hypertrophy or mimic hypertrophic obstructive cardiomyopathy. However, left ventricular systolic dysfunction and normal wall thickness can sometimes be encountered. Imaging studies (echocardiography, bone scintigraphy, cardiac magnetic resonance) and blood and urine analysis are usually the main tools for the diagnosis. Sometimes, a tissue biopsy may be necessary. Treatment, which is constantly improving, will be carried out on two fronts: treatment of the symptoms and complications that the disease already caused and prevention of additional amyloid deposits while managing the concomitant complications. The purpose of this article is to review the management of cardiac amyloidosis.

A Systematic Review of Tafamidis in Patients With Transthyretin Amyloid Cardiomyopathy

Transthyretin amyloid cardiomyopathy disease burden is increasing daily due to advancements in diagnostic and imaging modalities in the modern world. Tafamidis is one of many therapeutic options. The main objective of this review is to study the role of Tafamidis in slowing the progression of transthyretin cardiomyopathy (TTR-CM) by analyzing randomized controlled trials (RCTs) and non-RCTs of Tafamidis. We searched for published papers of Tafamidis in the English language in electronic databases like Google Scholar, PubMed, Cochrane Library, and PubMed Central. We imported the resulting articles from our search to Mendeley software. Four reviewers removed the duplicates and performed title and abstract screening of the articles. The same reviewers obtained the full-text of relevant articles and did full-text screening based on eligibility criteria. Finally, five reviewers performed a quality assessment of RCTs using the Cochrane risk of bias assessment and of non-RCTs by a checklist prepared by Downs and Black. Any disagreements about any process were resolved by a discussion with other authors. One RCT and five non-RCTs of Tafamidis were included in this systematic review. From the non-RCTs, stability was observed in different parameters like echocardiographic findings, cardiac biomarkers, and ECG in patients with transthyretin cardiomyopathy during the study duration with Tafamidis. ATTR-ACT (Tafamidis in Transthyretin Cardiomyopathy Clinical Trial) trial demonstrated reduction of cardiovascular events and all-cause mortality in the Tafamidis group in comparison to placebo. In both RCT and non-RCTs, Tafamidis was established as a safe and tolerable drug for patients with TTR-CM. Our study proved the role of Tafamidis in reducing cardiovascular events, all-cause mortality, and the progression of cardiac disease in TTR-CM patients. In addition to five non-RCTs, current evidence is based on the findings of only one RCT of Tafamidis. Hence, evidence from additional RCTs is required to strongly support the stability of parameters like echocardiographic findings, cardiac biomarkers, and ECG with Tafamidis use.

Use of biomarkers to diagnose and manage cardiac amyloidosis

Amyloidoses are characterized by the tissue accumulation of misfolded proteins into insoluble fibrils. The two most common types of systemic amyloidosis result from the deposition of immunoglobulin light chains (AL) and wild-type or variant transthyretin (ATTRwt/ATTRv). Cardiac involvement is the main determinant of outcome in both AL and ATTR, and cardiac amyloidosis (CA) is increasingly recognized as a cause of heart failure. In CA, circulating biomarkers are important diagnostic tools, allow to refine risk stratification at baseline and during follow-up, help to tailor the therapeutic strategy and monitor the response to treatment. Among amyloid precursors, free light chains are established biomarkers in AL amyloidosis, while the plasma transthyretin assay is currently being investigated as a tool for supporting the diagnosis of ATTRv amyloidosis, predicting outcome and monitor response to novel tetramer stabilizers or small interfering RNA drugs in ATTR CA. Natriuretic peptides (NPs) and troponins are consistently elevated in patients with AL and ATTR CA. Plasma NPs, troponins and free light chains hold prognostic significance in AL amyloidosis, and are evaluated for therapy decision-making and follow-up, while the value of NPs and troponins in ATTR is less well established. Biomarkers can be usefully integrated with clinical and imaging variables at all levels of the clinical algorithm of systemic amyloidosis, from screening to diagnosis and prognosis, and treatment tailoring.

Radionuclide Imaging of Cardiac Amyloidosis

This article provides a review of the latest radiotracers for planar/single-photon emission computed tomography (SPECT) and positron emission tomography (PET)/computed tomography (CT) imaging of cardiac amyloidosis, detailing their affinity, specificity, and sensitivity for cardiac amyloidosis. There are several tracers available that have differing affinities for transthyretin (ATTR) and immunoglobulin light chain (AL), and new developments in technology have allowed for disease burden quantification. Bone scintigraphy is an excellent option for visualizing ATTR cardiac amyloidosis. Negative testing does not exclude the possibility of AL cardiac amyloidosis and absolute quantitation of amyloid burden is limited.

Imaging cardiac innervation in hereditary transthyretin (ATTRm) amyloidosis: A marker for neuropathy or cardiomyopathy in case of heart failure?

BACKGROUND

Nuclear imaging modalities using 123Iodine-metaiodobenzylguanidine (123I-MIBG) and bone seeking tracers identify early cardiac involvement in ATTRm amyloidosis patients. However, little is known whether results from 123I-MIBG scintigraphy actually correlate to markers for either cardiac autonomic neuropathy or cardiomyopathy.

METHODS

All TTR mutation carriers and ATTRm patients who underwent both 123I-MIBG and 99mTechnetium-hydroxymethylene diphosphonate (99mTc-HDP) scintigraphy were included. Cardiomyopathy was defined as NT-proBNP > 365 ng/L, and cardiac autonomic neuropathy as abnormal cardiovascular reflexes at autonomic function tests. Late 123I-MIBG heart-to-mediastinum ratio (HMR) < 2.0 or wash-out > 20%, and any cardiac 99mTc-HDP uptake were considered as abnormal.

RESULTS

39 patients (13 carriers and 26 ATTRm patients) were included in this study. Patients with cardiomyopathy, with or without cardiac autonomic neuropathy, had lower late HMR than similar patients without cardiomyopathy [median 1.1 (range 1.0-1.5) and 1.5(1.2-2.6) vs 2.4 (1.4-3.8) and 2.5 (1.5-3.7), respectively, P < 0.001]. Late HMR and wash-out (inversely) correlated with NT-proBNP r = - 0.652 (P < 0.001) and r = 0.756 (P < 0.001), respectively. Furthermore, late HMR and wash-out (inversely) correlated with cardiac 99mTc-HDP uptake r = - 0.663 (P < 0.001) and r = 0.617 (P < 0.001), respectively.

CONCLUSION

In case of heart failure, 123I-MIBG scintigraphy reflects cardiomyopathy rather than cardiac autonomic neuropathy in ATTRm patients and TTR mutation carriers. 123I-MIBG scintigraphy may already be abnormal before any cardiac bone tracer uptake is visible.

Transthyretin cardiac amyloidosis: A treatable form of heart failure with a preserved ejection fraction

Cardiac amyloidosis (CA) is considered a rare disease with poor prognosis and limited therapeutic options. However, non-biopsy diagnostic modalities as well as emerging therapies are challenging this long-held belief. Radionuclide bone scintigraphy is increasingly being used in the diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CA). As such, it is expected that the number of patients diagnosed with ATTR-CA will continue to rise. Emerging therapies decrease the progressive morbidity and mortality associated with ATTR-CA. The importance of early recognition of ATTR-CA is imperative as prompt initiation of these novel agents is essential to maximize their therapeutic potential. Herein, we outline the current approach to diagnosis of ATTR-CA and review the therapeutic management of the disease.

Frequency of and Prognostic Significance of Cardiac Involvement at Presentation in Hereditary Transthyretin-Derived Amyloidosis and the Value of N-Terminal Pro-B-Type Natriuretic Peptide

The aim of this study is to assess the prevalence of cardiac involvement in hereditary transthyretin-derived (ATTRm) amyloidosis at the time of diagnosis and to determine the diagnostic and clinical value of N-terminal pro-B-type natriuretic peptide (NT-proBNP). The University Medical Center Groningen is the national center of expertise for amyloidosis. All consecutive patients between 1994 and 2016 with ATTRm amyloidosis were followed prospectively. Baseline was set at the time of the first positive biopsy. All patients underwent a standard cardiac and neurologic work-up. Cardiac involvement was defined by otherwise unexplained left and/or right ventricular wall hypertrophy on cardiac ultrasound and/or advanced conduction disturbances. Seventy-seven patients had ATTRm amyloidosis and were included in the study. The TTR V30M mutation was present in 30 patients (39%). In both the V30M and the non-V30M groups, the neurologic presentation dominated (77% vs 51%), whereas cardiac presentation was infrequent (7% vs 15%). Clinical work-up showed that cardiac involvement was present at baseline in 51% of all patients irrespective of genotype and was associated with increased overall mortality (hazard ratio 5.95, 95% confidence interval 2.12 to 16.7), independent from clinical confounders. At a cutoff level of 125 ng/L, NT-proBNP had a sensitivity of 92% for establishing cardiac involvement. In conclusion, irrespective of the frequent noncardiac presentation of ATTRm amyloidosis, cardiac involvement is already present at diagnosis in half of the patients and is associated with increased mortality. NT-proBNP is a useful marker to determine cardiac involvement in this disease.

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.

Cardiac amyloidosis: pathogenesis, clinical context, diagnosis and management options

Amyloidosis covers a group of disorders that can manifest in virtually any organ system in the body and is thought to be secondary to misfolding of extracellular proteins with subsequent deposition in tissues. The precursor protein that is produced in excess defines the specific amyloid type. This requires histopathological confirmation using Congo-red dye with its characteristic demonstration of green birefringence under cross-polarized light. There are three main types of amyloidosis associated with cardiac involvement: light-chain (AL), familial or senile (ATTR), and secondary (AA) amyloidosis. The frequency of cardiac involvement and prognosis varies among each type. Amyloid cardiomyopathy commonly manifests as heart failure and the presenting features are usually dyspnoea, oedema, angina, pre-syncope and syncope. The diagnosis of cardiac amyloidosis is very hard and can easily be misdiagnosed. Although the imaging studies (such as echocardiography and cardiovascular magnetic resonance) may guide the diagnosis, tissue biopsy is needed for confirmation. Management of cardiac amyloidosis initially is to treat the underlying heart failure. Pacemaker implantation is usually required in patients with any conduction abnormalities. Transplantation is the next step with worsening heart failure. However, the aim of any treatment in amyloidosis, irrespective of type, is to prevent further deposition of amyloid while managing concurrent symptoms. In this manuscript, we will discuss the pathogenesis of cardiac amyloidosis, diagnostic methods and management options.

Transthyretin Cardiac Amyloidosis in Black Americans

Transthyretin-related cardiac amyloidosis is a progressive infiltrative cardiomyopathy that mimics hypertensive and hypertrophic heart disease and often goes undiagnosed. In the United States, the hereditary form disproportionately afflicts black Americans, who when compared with whites with wild-type transthyretin amyloidosis, a phenotypically similar condition, present with more advanced disease despite having a noninvasive method for early identification (genetic testing). Although reasons for this are unclear, this begs to consider the inadequate access to care, societal factors, or a biological basis. In an effort to improve awareness and explore unique characteristics, we review the pathophysiology, epidemiology, and therapeutic strategies for transthyretin amyloidosis and highlight diagnostic pitfalls and clinical pearls for identifying patients with amyloid heart disease.

Impact of genotype and phenotype on cardiac biomarkers in patients with transthyretin amyloidosis - Report from the Transthyretin Amyloidosis Outcome Survey (THAOS)

Aim

Cardiac troponins and natriuretic peptides are established for risk stratification in light-chain amyloidosis. Data on cardiac biomarkers in transthyretin amyloidosis (ATTR) are lacking.

Methods and results

Patients (n = 1617) with any of the following cardiac biomarkers, BNP (n = 1079), NT-proBNP (n = 550), troponin T (n = 274), and troponin I (n = 108), available at baseline in the Transthyretin Amyloidosis Outcomes Survey (THAOS) were analyzed for differences between genotypes and phenotypes and their association with survival. Median level of BNP was 68.0 pg/mL (IQR 30.5–194.9), NT-proBNP 337.9 pg/mL (IQR 73.0–2584.0), troponin T 0.03 μg/L (IQR 0.01–0.05), and troponin I 0.08 μg/L (IQR 0.04–0.13). NT-proBNP and BNP were higher in wild-type than mutant-type ATTR, troponin T and I did not differ, respectively. Non-Val30Met patients had higher BNP, NT-proBNP and troponin T levels than Val30Met patients, but not troponin I. Late-onset Val30Met was associated with higher levels of troponin I and troponin T compared with early-onset. 115 patients died during a median follow-up of 1.2 years. Mortality increased with increasing quartiles (BNP/NT-proBNP Q1 = 1.7%, Q2 = 5.2%, Q3 = 21.7%, Q4 = 71.3%; troponin T/I Q1 = 6.5%, Q2 = 14.5%, Q3 = 33.9%, Q4 = 45.2%). Three-year overall-survival estimates for BNP/NT-proBNP and troponin T/I quartiles differed significantly (p<0.001). Stepwise risk stratification was achieved by combining NT-proBNP/BNP and troponin T/I. From Cox proportional hazards model, age, modified body mass index, mutation (Val30Met vs. Non-Val30Met) and BNP/NT-proBNP (Q1–Q3 pooled vs. Q4) were identified as independent predictors of survival in patients with mutant-type ATTR.

Conclusions

In this ATTR patient cohort, cardiac biomarkers were abnormal in a substantial percentage of patients irrespective of genotype. Along with age, mBMI, and mutation (Val30Met vs. Non-Val30Met), cardiac biomarkers were associated with surrogates of disease severity with BNP/NT-proBNP identified as an independent predictor of survival in ATTR.

Trial registration

ClinicalTrials.gov NCT00628745

Diagnosis, Prognosis, and Therapy of Transthyretin Amyloidosis

Transthyretin amyloidosis is a fatal disorder that is characterized primarily by progressive neuropathy and cardiomyopathy. It occurs in both a mutant form (with autosomal dominant inheritance) and a wild-type form (with predominant cardiac involvement). This article guides clinicians as to when the disease should be suspected, describes the appropriate diagnostic evaluation for those with known or suspected amyloidosis, and reviews the interventions currently available for affected patients.

Frequency of Cardiovascular Involvement in Familial Amyloidotic Polyneuropathy in Brazilian Patients

Background

Familial amyloidotic polyneuropathy (FAP) is a rare disease diagnosed in Brazil and worldwide. The frequency of cardiovascular involvement in Brazilian FAP patients is unknown.

Objective

Detect the frequency of cardiovascular involvement and correlate the cardiovascular findings with the modified polyneuropathy disability (PND) score.

Methods

In a national reference center, 51 patients were evaluated with clinical examination, electrocardiography (ECG), echocardiography (ECHO), and 24-hour Holter. Patients were classified according to the modified PND score and divided into groups: PND 0, PND I, PND II, and PND > II (which included PND IIIa, IIIb, and IV). We chose the classification tree as the statistical method to analyze the association between findings in cardiac tests with the neurological classification (PND).

Results

ECG abnormalities were present in almost 2/3 of the FAP patients, whereas ECHO abnormalities occurred in around 1/3 of them. All patients with abnormal ECHO also had abnormal ECG, but the opposite did not apply. The classification tree identified ECG and ECHO as relevant variables (p < 0.001 and p = 0.08, respectively). The probability of a patient to be allocated to the PND 0 group when having a normal ECG was over 80%. When both ECG and ECHO were abnormal, this probability was null.

Conclusions

Brazilian patients with FAP have frequent ECG abnormalities. ECG is an appropriate test to discriminate asymptomatic carriers of the mutation from those who develop the disease, whereas ECHO contributes to this discrimination.

Improving strategies for the diagnosis of cardiac amyloidosis

Amyloidosis refers to a group of rare but potentially fatal, protein misfolding diseases. The heart is frequently involved in the most common types, that is, immunoglobulin light chain and transthyretin amyloidosis and is the single most important predictor of patient outcomes. A major limitation in improving patient outcomes, in addition to developing novel therapeutics, is the late diagnosis of the disease. Once suspected, an organ for biopsy should be targeted and the amyloid type should be identified by mass spectrometry. An endomyocardial biopsy should be offered if cardiac involvement is in doubt. Echocardiography, MRI and nuclear imaging can provide valuable diagnostic and prognostic information and can secure the diagnosis if amyloid has been identified in an extracardiac tissue.

Cardiac findings and events observed in an open-label clinical trial of tafamidis in patients with non-Val30Met and non-Val122Ile hereditary transthyretin amyloidosis

A phase 2, open-label study in 21 patients with non-Val30Met and non-Val122Ile hereditary transthyretin amyloidosis showed that tafamidis (20 mg daily for 12 months) stabilized these transthyretin variants. We assessed cardiac amyloid infiltration and cardiac abnormalities in this same study population. At baseline, median age was 64.3 years, 11 patients were in NYHA class II, 13 had conduction abnormalities, 14 N-terminal pro-hormone brain natriuretic peptide concentrations >300 pg/ml, and 17 interventricular septal thickness >12 mm. Mean (SD) left ventricular ejection fraction was 60.3 % (9.96). Patients with normal heart rate variability increased from 4/19 at baseline to 8/19 at month 12 (p < 0.05). Cardiac biomarkers remained stable. Although four patients had increases in interventricular septal thickness ≥2 mm, the remainder had stable septal wall thickness. There were no clinically relevant changes in mean echocardiographic/electrocardiographic variables and no safety concerns.

Biomarkers in cardiology--part 1--in heart failure and specific cardiomyopathies

Cardiovascular diseases are the leading causes of mortality and morbidity in Brazil. The primary and secondary preventions of those diseases are a priority for the health system and require multiple approaches to increase their effectiveness. Biomarkers are tools used to more accurately identify high-risk individuals, to speed the diagnosis, and to aid in treatment and prognosis determination. This review aims to highlight the importance of biomarkers in clinical cardiology practice, and to raise relevant points of their use and the promises for the coming years. This document was divided into two parts, and this first one discusses the use of biomarkers in specific cardiomyopathies and heart failure.

Noninvasive risk stratification of patients with transthyretin amyloidosis

OBJECTIVES

We sought to evaluate noninvasive parameters by electrocardiography, echocardiography, technetium-99m-3,3-diphosphono-1,2-propanodicarboxylic acid ((99m)Tc-DPD) scintigraphy, and cardiac magnetic resonance for the prediction of all-cause mortality in patients with cardiac transthyretin amyloidosis (ATTR).

BACKGROUND

ATTR may present with highly variable symptoms, including polyneuropathy and cardiomyopathy, the latter being associated with a poor outcome. However, data on noninvasive risk stratification of ATTR are limited.

METHODS

A total of 70 patients with ATTR were evaluated by echocardiography, cardiac biomarkers, and (99m)Tc-DPD scintigraphy. Cardiac magnetic resonance was performed in 30 patients. Echocardiographic findings and plasma levels of biomarkers were correlated with results of quantitative analysis of scintigraphy using a region-of-interest technique (whole-body as well as heart tracer retention). Receiver-operating characteristic (ROC) analysis was performed to calculate a cutoff value of (99m)Tc-DPD scintigraphy for heart retention for the diagnosis of cardiac amyloid involvement with the highest sensitivity and specificity. Univariate and multivariate analyses were performed in patients with cardiac involvement (n = 60) to determine noninvasive predictors of all-cause mortality.

RESULTS

Scintigraphy findings correlated with morphological (interventricular septum thickness, left ventricular hypertrophy index) as well as functional (mitral annular systolic velocity, mitral/tricuspid annular plane systolic excursion) findings, cardiac biomarkers, renal function, and late gadolinium enhancement. The ROC-derived cutoff for the detection of cardiac amyloidosis by scintigraphic heart tracer retention was 4.8%. Univariate Cox regression revealed N-terminal pro-B-type natriuretic peptide, troponin T, mitral annular plane systolic excursion, and left ventricular hypertrophy index as predictors of all-cause mortality. However, on multivariate analysis, troponin T remained the only independent predictor of survival. The ROC-derived cutoff value of troponin T predicting all-cause mortality with the highest sensitivity (80.0%) and specificity (68.7%) was 0.0375 ng/l.

CONCLUSIONS

Quantitative analysis of tracer retention is capable of characterizing the severity of cardiac involvement in ATTR. By multivariate analysis, troponin T remained the only independent predictor of survival.

Usefulness of plasma B-type natriuretic peptide as a prognostic marker of cardiac function in senile systemic amyloidosis and in familial amyloidotic polyneuropathy

OBJECTIVE

In senile systemic amyloidosis (SSA), a common age-related amyloidosis, wild-type transthyretin accumulates in tissues, with a primary result being cardiac dysfunction. Here, we aimed to clarify the usefulness of B-type natriuretic peptide (BNP) as a prognostic marker of cardiac function in SSA and in familial amyloidotic polyneuropathy (FAP).

METHODS AND RESULTS

We studied 13 patients with severe SSA and 14 patients with FAP. SSA patients, but not FAP patients, demonstrated a significant correlation of log BNP with the echocardiographic diastolic marker E/e' ratio (r = 0.78, p < 0.01). SSA patients also showed significant correlations between log BNP and log C-reactive protein or log high-sensitive troponin T (r = 0.70, p < 0.01; r = 0.64, p < 0.05). FAP patients, however, had significant correlations between log BNP and left ventricular wall thickness (intraventricular septum thickness diastole and posterior wall thickness diastole) (r = 0.73, p < 0.01; r = 0.77, p < 0.01). The mean log BNP level in the follow-up period was significantly higher than that in the diagnostic period in SSA patients (2.65 ± 0.45 versus 2.36 ± 0.40, p < 0.01) but not in FAP patients (1.91 ± 0.56 versus 1.93 ± 0.45, p = 0.87). An especially notable phenomenon was the high plasma BNP level (≥180 pg/ml) in SSA patients.

CONCLUSION

Plasma BNP levels may be a useful prognostic marker of cardiac function in SSA.

Role of natriuretic peptide to predict cardiac abnormalities in patients with hereditary transthyretin amyloidosis

BACKGROUND

Familial amyloid polyneuropathy (FAP) mainly targets the peripheral nervous system and heart. Early noninvasive detection of cardiac impairment is critical for therapeutic management.

AIM

To assess if amino-terminal pro-brain natriuretic peptide (NT-proBNP) or troponin T (cTnT) can predict echocardiographic left-ventricle (LV) impairment in FAP.

METHODS

Thirty-six asymptomatic carriers and patients with FAP had echocardiographic measurement of left-ventricular (LV) systolic function, hypertrophy (LVH) and estimation of filling pressure (FP).

RESULTS

Overall, median age, NT-proBNP, and LV ejection fraction were, respectively, 59 years (41-74), 323 pg/ml (58-1960), and 60% (51-66). Twelve patients had increased cTnT. Prevalence of ATTR gene mutations was 53% for Val30Met. Four individuals were asymptomatic, 6 patients had isolated neurological clinical signs, and 26 had echo-LV abnormalities. The ROC curve identified NT-proBNP patients with echo-LV abnormalities (area: 0.92; (0.83-0.99), p = 0.001) at a threshold >82 pg/ml with a sensitivity of 92%, and a specificity of 90%. Increased in NT-proBNP occurred in patients with SD and/or LVH with or without increase in FP. Elevated cTnT (>0.01 ng/ml) was only observed in patients with LVH and systolic dysfunction, with or without FP.

CONCLUSION

In FAP, NT-proBNP was associated with cardiac impairment suggesting that NT-proBNP could be used in carriers or in FAP patients with only neurologic symptoms for identifying the appropriate time to start cardiac echocardiographic assessment and follow-up. cTnT identified patients with severe cardiac disease.

Severe heart disease in an unusual case of familial amyloid polyneuropathy type I

Familial amyloid polyneuropathy type I (FAP type I) is a rare hereditary systemic amyloidosis caused by the Val30Met mutation in the transthyretin (TTR) gene. The clinical onset and spectrum are variable and depend on phenotypic heterogeneity. Cardiac complications (dysrhythmias and conduction disturbances, cardiomyopathy and dysautonomia) indicate a poor prognosis, even after liver transplantation. We report an atypical case of FAP type I, highlighting the severe cardiac involvement and its complications. Early diagnosis of amyloid heart disease is increasingly important in the context of several clinical trials of promising new and experimental drugs.

Senile systemic amyloidosis: clinical features at presentation and outcome

BACKGROUND

Cardiac amyloidosis is a fatal disease whose prognosis and treatment rely on identification of the amyloid type. In our aging population transthyretin amyloidosis (ATTRwt) is common and must be differentiated from other amyloid types. We report the clinical presentation, natural history, and prognostic features of ATTRwt compared with cardiac-isolated AL amyloidosis and calculate the probability of disease diagnosis of ATTRwt from baseline factors.

METHODS AND RESULTS

All patients with biopsy-proven ATTRwt (102 cases) and isolated cardiac AL (36 cases) seen from 2002 to 2011 at the UK National Amyloidosis Center were included. Median survival from the onset of symptoms was 6.07 years in the ATTRwt group and 1.7 years in the AL group. Positive troponin, a pacemaker, and increasing New York Heart Association (NYHA) class were associated with worse survival in ATTRwt patients on univariate analysis. All patients with isolated cardiac AL and 24.1% of patients with ATTRwt had evidence of a plasma cell dyscrasia. Older age and lower N-terminal pro-B-type natriuretic peptide (NT pro-BNP) were factors significantly associated with ATTRwt. Patients aged 70 years and younger with an NT pro-BNP <183 pmol/L were more likely to have ATTRwt, as were patients older than 70 years with an NT pro-BNP <1420 pmol/L.

CONCLUSIONS

Factors at baseline associated with a worse outcome in ATTRwt are positive troponin T, a pacemaker, and NYHA class IV symptoms. The age of the patient at diagnosis and NT pro-BNP level can aid in distinguishing ATTRwt from AL amyloidosis.

Transthyretin familial amyloid polyneuropathy

TTR FAP is characterized by phenotypic and genotypic heterogeneity. The severity of polyneuropathy along with autonomic dysfunction and heart involvement makes it a life-threatening disease. This protein is mainly produced by the liver. Molecular genetic testing is essential in the diagnostic strategy. TTR-Val30Met is the most frequent substitution, resulting in a guanine to cytosine mutation in exon 2 of the gene. It is virtually the only variant detected in Portugal, Brazil, and Sweden. By contrast, as many as 30 different TTR variants are reported in Japan and in other European countries. A less severe phenotype with late onset has been reported. Diagnosis should be performed as early as possible since upcoming pharmacological therapeutic approaches are now available, in addition to liver transplantation.

New insights into the clinical evaluation of hereditary transthyretin amyloidosis patients: a single center's experience

Over the last decade, new medical treatment modalities have emerged based on increased insights into amyloid formation. With the increased possibilities for treatment of amyloidosis caused by transthyretin (TTR) amyloid deposits comes the need for diagnostic procedures for early diagnosis and better tools to follow disease progression. This is of particular importance in clinical trials evaluating the efficacy of new treatments. Until recently, the treatment of TTR amyloidosis (ATTR) was based solely on liver transplantation, a procedure that has halted disease progression in many patients. Liver transplantation has been especially effective in patients under the age of 50 years carrying the TTR V30M mutation, whereas the outcome of the procedure has been variable for others, particularly elderly male patients and those carrying a non-V30M mutation. This review concentrates on new insights derived from our center's experience with liver transplantation, how to implement this experience in evaluation of new treatment modalities for ATTR, and how to facilitate early diagnosis of neuropathy with easily available diagnostic tools. Attention has focused on manifestations of the disease that involve the heart and the peripheral nervous system; change in peripheral nerve function has been the primary endpoint in two controlled clinical trials, one finished and one ongoing. New insights into the amyloid formation process and the lessons learned from liver transplantation give the opportunity to design potentially effective treatment modalities for ATTR. It appears reasonable to suspect that a combination of different treatment modalities may be required to treat the disease, and that different treatment regimes will be designed according to the phenotype of the disease. For the patients and their relatives there is now a solid foundation for optimism, with prospects of several effective medical treatment possibilities within the coming decade.

Cardiac phenotype and clinical outcome of familial amyloid polyneuropathy associated with transthyretin alanine 60 variant

AIMS

Familial amyloid polyneuropathy (FAP) is a dominantly inherited multi-system disease associated with transthyretin (TTR) mutations. Previous series have predominantly described patients with the TTR variant Val30Met (V30M), which is the most prevalent cause of FAP worldwide. Here, we report the dominant cardiac phenotype and outcome of FAP associated with TTR Thr60Ala (T60A), the most common UK variant.

METHODS AND RESULTS

Sixty consecutive patients with FAP associated with TTR T60A (FAP T60A) were prospectively evaluated in two centres between 1992 and 2009. Median (range) age of symptom development was 63 (45-78) years. A family history of amyloidosis was present in only 37%. Autonomic and peripheral neuropathy were present in 44 and 32 patients, respectively, at diagnosis. Cardiac involvement was evident on echocardiography at diagnosis in 56 patients, but was associated with reduced QRS voltages on electrocardiography in only 16% evaluable cases. Seventeen patients received implantable anti-arrhythmic devices. Median survival was 6.6 years following onset of symptoms and 3.4 years from diagnosis, and correlated with serum N-terminal prohormone brain natriuretic peptide (NT-proBNP) concentration and certain echocardiographic parameters at the latter. Orthotopic liver transplantation (OLT), performed to eliminate the predominant hepatic source of variant TTR T60A protein, was performed in eight patients including one who received a concomitant cardiac transplant. Cardiac amyloidosis progressed in all lone OLT recipients, of whom four died within 5 years.

CONCLUSION

Cardiac amyloidosis is almost always present at diagnosis in FAP T60A, and is a major determinant of its poor prognosis. Outcome of liver transplantation in FAP T60A has been discouraging.

Heart complications in familial transthyretin amyloidosis: impact of age and gender

Heart arrhythmia is common in Swedish patients with familial amyloidotic polyneuropathy (FAP), as well as cardiomyopathy. We investigated the relationship between Holter ECG and echocardiographic findings in 108 FAP patients, with particular focus on age and gender differences. Female patients were younger than male patients at symptom onset (p < 0.01). Only 4 of 39 patients with septal hypertrophy were females. Regression analysis showed that age of onset, gender and duration of disease were significantly related with intraventricular septum (IVS) thickness. Sixty-five patients (25 females) presented with abnormal 24-h ECG recordings. IVS thickness was not significantly related to conduction disturbances or the presence of ventricular arrhythmia (VA). However, IVS thickness and atrial dimension were both related to increased rate of supraventricular arrhythmia (SVA). Male gender was clearly associated with more pronounced septal thickness of the heart. Conduction disturbances were not related to IVS thickness, indicating that the distribution and extent of infiltration of the heart by amyloid are heterogeneous and related to gender and age of onset. These findings highlight the necessity of 24-h ECGs to detect conduction disturbances, due to their occurrence in the absence of echocardiographic evidence of amyloid deposition in the myocardium.

Amyloid load in fat tissue reflects disease severity and predicts survival in amyloidosis

OBJECTIVE

The severity of systemic amyloidosis is thought to be related to the extent of amyloid deposition. We studied whether amyloid load in fat tissue reflects disease severity and predicts survival.

METHODS

We studied all consecutive patients with systemic amyloidosis seen between January 1994 and January 2007 in our tertiary referral center. Congo red-stained abdominal fat smears were graded by 2 observers using a validated semiquantitative scoring system. Disease severity was measured by the total number of major organs involved and the extravascular retention of the serum amyloid P component (EVR(24)). The association of amyloid load in fat tissue with disease severity and overall survival was studied using multiple regression analysis.

RESULTS

Two hundred twenty patients were included in the study (120 with AL amyloidosis, 66 with AA amyloidosis, and 34 with ATTR amyloidosis). Amyloid grade in fat tissue was associated with the number of major organs involved and EVR(24). Female sex turned out to be associated with a higher grade of amyloid in fat tissue than male sex. Amyloid grade in fat tissue was an independent predictor of decreased survival, as were heart involvement, the number of organs involved, AA or AL type of amyloid, and age.

CONCLUSION

The amount of amyloid in subcutaneous fat tissue in systemic amyloidosis reflects disease severity, as measured by the number of organs involved and EVR(24), and predicts decreased survival independent of other well-known factors.

Transthyretin-related amyloidoses and the heart: a clinical overview

A nonhereditary form of systemic amyloidosis associated with wild-type transthyretin causes heart involvement predominantly in elderly men (systemic senile amyloidosis, or SSA). However, hereditary transthyretin-related amyloidosis (ATTR) is the most frequent form of familial systemic amyloidosis, a group of severe diseases with variable neurological and organ involvement. ATTR remains a challenging and widely underdiagnosed condition, owing to its extreme phenotypic variability: the clinical spectrum of the disease ranges from an almost exclusive neurologic involvement to a strictly cardiac presentation. Such heterogeneity principally results from differential effects of the various reported transthyretin mutations, the geographic region the patient is from and, in the case of the most common mutation, Val30Met, whether or not large foci of cases occur (endemic versus nonendemic aggregation). Genetic or environmental factors (such as age, sex, and amyloid fibril composition) also contribute to the heterogeneity of ATTR, albeit to a lesser extent. The existence of exclusively or predominantly cardiac phenotypes should lead clinicians to consider the possibility of ATTR in all patients who present with an unexplained increase in left ventricular wall thickness at echocardiography. Assessment of such patients should include an active search for possible red flags that can point to the correct final diagnosis.

Serum levels of NT-proBNP as surrogate for cardiac amyloid burden: new evidence from gadolinium-enhanced cardiac magnetic resonance imaging in patients with amyloidosis

BACKGROUND

The prognostic value of NT-proBNP has been recognized in patients with amyloidosis complicated by cardiac involvement. We aimed to use contrast enhanced cardiac magnetic resonance imaging (CMR) to identify functional and structural alterations related to levels of NT-proBNP better to understand the mechanisms of its release in cardiac amyloidosis.

METHODS AND RESULTS

CMR was performed on a 1.5-T scanner in 34 patients with biopsy proven amyloid light chain (AL; n = 27) or hereditary transthyretin related (TTR; n = 7) amyloidosis. NT-proBNP was higher in patients with (n = 25) compared to patients without cardiac involvement (n = 9) (2931 (IQR: 972-8629; min-max: 25-27,277) pg/ml vs. 177 (IQR: 71-1431; min-max: 22-7935) pg/ml, p = 0.008). ROC analysis identified a NT-proBNP of <2426.5 pg/ml as optimal discriminator for event free survival (682 +/- 65 days). NT-proBNP did not correlate with LV- ejection fraction, end-diastolic and end-systolic volumes or stroke volume. There was a moderate correlation between NT-proBNP and LV-mass (R = 0.52, p = 0.003) and extent of late gadolinium enhancement (LGE; R = 0.41, p = 0.04).

CONCLUSIONS

This study confirms the prognostic value of NT-proBNP in patients with AL and TTR amyloidosis and provides the novel finding that NT-proBNP correlates with surrogates of myocardial amyloid burden such as LV-mass and LGE, supporting the concept of NT-proBNP as a biomarker reflecting the severity of cardiac amyloid infiltration.

Systemic cardiac amyloidoses: disease profiles and clinical courses of the 3 main types

BACKGROUND

Most studies of amyloidotic cardiomyopathy consider as a single entity the 3 main systemic cardiac amyloidoses: acquired monoclonal immunoglobulin light-chain (AL); hereditary, mutated transthyretin-related (ATTRm); and wild-type transthyretin-related (ATTRwt). In this study, we compared the diagnostic/clinical profiles of these 3 types of systemic cardiac amyloidosis.

METHODS AND RESULTS

We conducted a longitudinal study of 233 patients with clear-cut diagnosis by type of cardiac amyloidosis (AL, n=157; ATTRm, n=61; ATTRwt, n=15) at 2 large Italian centers providing coordinated amyloidosis diagnosis/management facilities since 1990. Average age at diagnosis was higher in AL than in ATTRm patients; all ATTRwt patients except 1 were elderly men. At diagnosis, mean left ventricular wall thickness was higher in ATTRwt than in ATTRm and AL. Left ventricular ejection fraction was moderately depressed in ATTRwt but not in AL or ATTRm. ATTRm patients less often displayed low QRS voltage (25% versus 60% in AL; P<0.0001) or low voltage-to-mass ratio (1.1+/-0.5 versus 0.9+/-0.5; P<0.0001). AL patients appeared to have greater hemodynamic impairment. On multivariate analysis, ATTRm was a strongly favorable predictor of survival, and ATTRwt predicted freedom from major cardiac events.

CONCLUSIONS

AL, ATTRm, and ATTRwt should be considered 3 different cardiac diseases, probably characterized by different pathophysiological substrates and courses. Awareness of the diversity underlying the cardiac amyloidosis label is important on several levels, ranging from disease classification to diagnosis and clinical management.

Tissue Doppler and strain imaging: a new tool for early detection of cardiac amyloidosis

Using traditional echocardiography, the diagnosis of cardiac amyloidosis (CA) is often only possible in advanced stage when recommended therapies may have adverse effects. The aim of our study was to evaluate whether additional information can be derived from Tissue and strain Doppler imaging (TDI and SDI). Forty patients with systemic amyloidosis and 24 healthy subjects underwent traditional, tissue and strain Doppler echocardiography. Patients were classified having CA if mean wall thickness (mT), was half of the sum septum and posterior wall thickness, was > or =12 mm. The following parameters were evaluated: peak early diastolic velocity (Em) as index of ventricular relaxation, mitral E-wave to Em ratio (E/Em) as index of left ventricular (LV) filling pressure and mean LV strain peak curves (mSt) as global long-axis contraction index. In non cardiac amyloidosis (NCA), both Em and mSt were lower than in age matched controls (p < 0.01, p < 0.05, respectively) and higher than in CA (p < 0.01 and p < 0.01, respectively). Both Em and mSt were related to mT (p < 0.001). A significant (p < 0.01) nonlinear relation was observed between plasma terminal of pro B-natriuretic peptide and mT, Em, E/Em and mSt. TDI and SDI are able to detect amyloid myocardial involvement in such an early stage that cannot be evidenced by using traditional echocardiography.

Evaluation of myocardial changes in familial amyloid polyneuropathy after liver transplantation

OBJECTIVE

The progression of cardiac amyloidosis is a prognostic factor after liver transplantation (LT) in familial amyloid polyneuropathy (FAP). The aim of this study was to assess myocardial changes in FAP amyloidgenic transthyretin (ATTR) Val30Met after LT.

PATIENTS AND METHODS

Twelve Japanese FAP ATTR Val30Met patients who underwent LT and were followed for more than 2 years, were examined with serial echocardiography after LT. Serum BNP levels were measured in 9 patients.

RESULTS

A significant increase in mean left atrial diameter and interventricular septal thickness was observed after LT. The increase in left atrial diameter was correlated with the presence of granular sparkling echo (GSE) at preoperative examination. Serum brain natriuretic peptide (BNP) levels in patients with left atrial diameter dilation (152.0+/-157.6 pg/mL) were higher than in those without left atrial diameter dilation (32.0+/-30.0 pg/mL).

CONCLUSION

LAD and IVS were significantly increased after LT compared with preoperative examinations in Japanese FAP ATTR Val30Met patients. BNP is an important biochemical indicator of myocardiac dysfunction in FAP patients. GSE is a useful echocardiographic marker to predict cardiac amyloidosis after LT.