Left ventricular structure and function in transthyretin-related versus light-chain cardiac amyloidosis

Prognosis of Light Chain Amyloidosis With Preserved LVEF: Added Value of 2D Speckle-Tracking Echocardiography to the Current Prognostic Staging System

OBJECTIVES

This study evaluated whether 2-dimensional speckle-tracking echocardiography (2D-STE) has incremental value for prognosis over traditional clinical, echocardiographic, and serological markers-with main focus on the current prognostic staging system-in light-chain (AL) amyloidosis patients with preserved left ventricular ejection fraction.

BACKGROUND

Cardiac amyloidosis (CA) is the major determinant of outcome in AL amyloidosis. The current prognostic staging system is based primarily on serum levels of cardiac troponin T (cTnT), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and free light chain differential (FLC-diff).

METHODS

Consecutive patients with biopsy-proven AL amyloidosis and left ventricular ejection fraction ≥55% were divided into group 1 with CA (n = 63) and group 2 without CA (n = 87). Global longitudinal strain (GLS) by 2D-STE was performed with Vivid E9 (GE Healthcare Co., Milwaukee, Wisconsin) and syngo Velocity Vector Imaging (VVI) software (Siemens Medical Solutions USA, Inc., Malvern, Pennsylvania) (GLS_GE and GLS_VVI, respectively).

RESULTS

Thirty-two deaths (51%) occurred in group 1 and 13 (15%) in group 2 (p ≤ 0.001). Group 1 had thicker walls, lower early diastolic tissue Doppler velocity at septal mitral annulus, and greater left ventricular mass, left atrial volume, glomerular filtration rate, FLC-diff, cTnT, and NT-proBNP (p < 0.001). For the entire cohort, GLS_GE ≥ -14.81, GLS_VVI ≥-15.02, cTnT, NT-proBNP, FLC-diff, age, left ventricular wall thickness, early diastolic tissue Doppler velocity at septal mitral annulus, diastolic dysfunction grade, glomerular filtration rate, deceleration time, and left atrial volume were univariate predictors of death. In a multivariate Cox model, GLS_GE ≥-14.81 (hazard ratio [HR]: 2.68; 95% confidence interval [CI]: 1.07 to 7.13; p = 0.03), FLC-diff, NT-proBNP, and age were independent predictors of survival. There was also a strong trend for GLS_VVI ≥-15.02 (HR: 2.44; 95% CI: 0.98 to 6.33; p = 0.055). Using a nested logistic regression model, GLS_GE (p = 0.03) and GLS_VVI (p = 0.05) provided incremental prognostic value over cTnT, NT-proBNP, and FLC-diff. For survival analysis limited to group 2 (non-CA), GLS_GE and GLS_VVI both predicted all-cause mortality (GLS_GE HR: 1.23; 95% CI: 1.03 to 1.47 [p = 0.02]; GLS_VVI HR: 1.22; 95% CI: 1.01 to 1.49 [p = 0.04], respectively).

CONCLUSIONS

2D-STE predicted outcome and provided incremental prognostic information over the current prognostic staging system, especially in the group without CA.

Cumulative Burden of Myocardial Dysfunction in Cardiac Amyloidosis Assessed Using Four-Chamber Cardiac Strain

BACKGROUND

The aim of this study was to test the hypothesis that prognosis in patients with cardiac amyloidosis is closely coupled with amyloid burden in all four cardiac chambers. The goal was to evaluate longitudinal strain (LS) in each cardiac chamber and to determine whether LS in specific cardiac chambers is preferentially associated with prognosis over conventional two-dimensional echocardiographic parameters in patients with cardiac amyloidosis.

METHODS

Patients with two phenotypes of left ventricular (LV) hypertrophy (cardiac amyloidosis in 55 patients and nonobstructive hypertrophic cardiomyopathy in 40 patients) and 55 healthy subjects were retrospectively enrolled for the simultaneous assessment of LS of all four cardiac chambers in the apical four-chamber view. Patients with cardiac amyloidosis were followed up to record major adverse cardiovascular events, including cardiac death, heart transplantation, nonfatal myocardial infarction, ventricular tachyarrhythmia, and exacerbation of heart failure requiring hospitalization.

RESULTS

LS in each chamber was significantly depressed in patients with both LV hypertrophy phenotypes compared with healthy subjects. Right atrial LS was significantly lower in patients with cardiac amyloidosis than those with nonobstructive hypertrophic cardiomyopathy after adjusting for LV ejection fraction and LV mass index. During a median follow-up period of 10 months, major adverse cardiovascular events developed in 22 patients with cardiac amyloidosis. Four-chamber LS were significantly associated with major adverse cardiovascular events, with incremental value over traditional echocardiographic parameters.

CONCLUSIONS

Cardiac amyloidosis involves all cardiac chambers, and thus, chamber-specific strain analysis may be useful to assess the total cumulative burden of cardiac dysfunction.

Prognostic value of right ventricular systolic function in cardiac amyloidosis

BACKGROUND

Right ventricular (RV) dysfunction is a strong predictor of poor outcomes in heart failure. Its prognostic meaning in cardiac amyloidosis (CA) is under-investigated.

METHODS

Hundred and twenty nine patients with suspected CA and an interventricular septum thickness (IVST) ≥ 12 mm underwent echocardiography with measurement of left ventricular (LV) and RV longitudinal strain (LS), late gadolinium-enhancement (LGE) cardiac MRI, and standard evaluation.

RESULTS

Among 82 confirmed CA, types were immunoglobulin light chain (AL, n = 26), hereditary transthyretin (m-TTR, n = 37) and senile (WT-TTR, n = 19). Compared to those without, CA patients had significantly lower RV fractional shortening (RV-FS), tricuspid annular plane systolic excursion (TAPSE), tissue Doppler systolic velocity, and global RV-LS, without any difference among the CA types. RV-LGE, observed in 62% of CA patients, was associated with lower global and basal RV-FS. Median follow-up was 8(2; 16) months. Using multivariate analysis, NYHA-class and low TAPSE independently predicted major adverse cardiac event (MACE) defined as death, heart transplantation and acute heart failure. Independent determinants of TAPSE < 14 mm, the best cut-off value, were LV ejection fraction (LVEF), estimated filling pressure (E/E'), NT-proBNP and pulmonary artery pressure, but not RV-LGE.

CONCLUSIONS

RV dysfunction is common in CA. Its routine evaluation by a simple TAPSE may be an aid in assessing the prognosis of CA patients.

Cardiac Amyloid Imaging with 18F-Florbetaben PET: A Pilot Study

Our aim was to determine the feasibility of ¹⁸F-florbetaben PET in diagnosing cardiac amyloidosis.

METHODS

¹⁸F-florbetaben PET was performed on 14 patients: 5 amyloid light chain, 5 amyloid transthyretin, and 4 control with hypertensive heart disease. Qualitative and quantitative assessments of ¹⁸F-florbetaben activity were performed using the SUV_mean of the left ventricular myocardium and blood pool and calculation of target-to-background SUV ratio. Myocardial ¹⁸F-forbetaben retention was also calculated as the percentage mean myocardial SUV change between 0 and 5 min and 15 and 20 min after radiotracer injection. Global left ventricular longitudinal and right ventricular free wall longitudinal strain were calculated using 2-dimensional speckle-tracking echocardiography.

RESULTS

Target-to-background SUV ratio and percentage myocardial ¹⁸F-forbetaben retention were higher in amyloid patients than in hypertensive controls. A cutoff of 40% was able to differentiate between cardiac amyloid patients and hypertensive controls. Percentage myocardial ¹⁸F-forbetaben retention was an independent determinant of both global left ventricular longitudinal and right ventricular free wall longitudinal strain via an inverse curve relationship.

CONCLUSION

¹⁸F-florbetaben PET imaging can accurately identify and differentiate between cardiac amyloidosis and hypertensive heart disease. Percentage myocardial ¹⁸F-florbetaben retention was an independent determinant of myocardial dysfunction in cardiac amyloidosis.

Diagnostic accuracy of cardiovascular magnetic resonance for patients with suspected cardiac amyloidosis: a systematic review and meta-analysis

Background

This study is a systematic review and meta-analysis of the diagnostic value of cardiovascular magnetic resonance (CMR) in cardiac amyloidosis (CA).

Methods

A wide variety of electronic databases were searched for studies of CMR that reported the diagnostic accuracy in patients with suspected CA. Research manuscripts were subjected to further systematic review and meta-analysis. Methodological evaluation was performed under the guidance of the Quality Assessment of Diagnostic Accuracy Studies −2 (QUADAS–2). Heterogeneity was assessed, and a random-effects model was used to assess the diagnostic effects of CMR on pooled sensitivity, pooled specificity, and summary receiver operating characteristics (SROC).

Results

Seven studies that reported the performance of CMR for CA were included in the present systematic review, among which five studies (257 patients) that evaluated the diagnostic accuracy of late gadolinium enhancement (LGE) CMR were analyzed in the present meta-analysis. Heterogeneity was observed only in specificity. A summary sensitivity and specificity of 85 % (95 % CI: 77–91 %) and 92 % (95 % CI: 83–97 %) indicated a high diagnostic accuracy of LGE for CA. The AUC of SROC curve was 0.9530, suggesting that LGE is an effective way of diagnosing patients with possible cardiac involvement in amyloidosis.

Conclusions

LGE–CMR seems to have a relatively high diagnostic accuracy for amyloidosis patients with possible cardiac involvement. Combined CMR techniques may provide important information for the selection of suitable therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-016-0311-6) contains supplementary material, which is available to authorized users.

Use of Noninvasive Imaging in Cardiac Amyloidosis

OPINION STATEMENT

Cardiac involvement in amyloidosis is associated with poor outcomes. The standard test for the diagnosis of cardiac amyloidosis is endomyocardial biopsy but given current advances in noninvasive imaging, the diagnosis is frequently obtained or strongly suspected without biopsy. Echocardiography is the most utilized cardiac imaging modality, particularly myocardial strain measures with this modality have been found to be a predictor of clinical outcomes, superior to traditional parameters. Other known imaging modalities with new, useful protocols for this pathology include nuclear imaging and cardiac magnetic resonance (CMR). In particular, CMR has excellent sensitivity and specificity.

Wild-Type Transthyretin Cardiac Amyloidosis: Novel Insights From Advanced Imaging

Amyloidosis is caused by extracellular deposition of abnormal protein fibrils, resulting in destruction of tissue architecture and impairment of organ function. The most common forms of systemic amyloidosis are light-chain and transthyretin-related (ATTR). ATTR can result from an autosomal dominant hereditary transmission of mutated genes in the transthyretin or from a wild-type form of disease (ATTRwt), previously known as senile cardiac amyloidosis. With the aging of the worldwide population, ATTRwt will emerge as the most common type of cardiac amyloidosis that clinicians encounter. Diagnosis of systemic amyloidosis is often delayed, either because of the false assumption that it is a rare disease, or because of misdiagnosis as a result of mistaking it with other conditions. Clinicians must integrate clinical clues from history, physical examination, and common diagnostic tests to raise suspicion for ATTRwt. The historical gold standard for diagnosis of cardiac amyloid is endomyocardial biopsy analysis with pathological distinction of precursor protein type, but this method often results in delayed diagnosis because of the limited availability of expertise to perform and interpret the endomyocardial biopsy specimen. Emerging noninvasive imaging modalities provide easier, accurate screening for ATTRwt. These modalities include advanced echocardiography, using strain imaging and the myocardial contraction fraction; nuclear scintigraphy, which can differentiate between ATTR and light-chain cardiac amyloid; and cardiac magnetic resonance imaging, using extracellular volume measurement, late gadolinium enhancement, and distinct T1 mapping. These novel approaches reveal insights into the prevalence, clinical course, morphological effects, and prognosis of ATTRwt.

Subtype-Specific Interactions and Prognosis in Cardiac Amyloidosis

Background

Light chain (AL) and transthyretin (ATTR) amyloidosis have a similar effect on myocardial function but very different disease trajectories and survival. However, limited data are available evaluating subtype‐specific predictors of outcomes in a large contemporary cohort.

Methods and Results

We retrospectively investigated 360 patients at the time of initial diagnosis of cardiac amyloidosis (191 AL and 169 ATTR) from 2002 to 2014. Clinical, laboratory, electrical, and morphologic covariates were evaluated based upon amyloid subtype. ATTR etiology was associated with older age, more chronic medical conditions, and the use of standard heart failure medical therapy. Left ventricular mass index and electrocardiographic voltage were higher in ATTR, while there was no difference in ejection fraction or markers of diastology between subtypes. A multivariable Cox model was generated using previously identified predictors of negative outcomes in cardiac amyloidosis and analyzed after stratification for subsequent amyloid‐specific treatment. An AL etiology was the most predictive variable (hazard ratio 3.143, P<0.001) of 3‐year all‐cause mortality. The only covariate that showed a significantly greater magnitude of effect on mortality in 1 amyloid subtype versus the other was amyloid‐specific treatment in AL (P=0.015). The magnitude of effect of other variables on mortality did not significantly differ between subtypes.

Conclusions

Clinical, morphological, electrical, and biomarker data do not significantly interact with amyloid subtype in its association with mortality, despite the fact that the prognosis in each subtype differs greatly. This suggests an additional factor or factors (such as light chain toxicity) contributing to poorer outcomes in AL amyloid.

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.

Comparison of the standard and speckle tracking echocardiographic features of wild-type and mutated transthyretin cardiac amyloidoses

AIMS

To compare cardiac function in patients with the two types of transthyretin (TTR)-related amyloidoses [wild-type (wt) and mutated (m) TTR amyloidoses (ATTR)] using standard and speckle tracking echocardiography (STE).

METHODS AND RESULTS

Twenty-one consecutive patients with biopsy-proved ATTRwt were compared with 21 patients with ATTRm from the database, matched by age and left ventricular (LV) wall thickness (n = 135, ATTRm). All patients were examined using 2D echocardiography. Apical four- and two-chamber, and long-axis views and basal, mid, and apical short-axis views were used to examine LV longitudinal, circumferential, and radial strains. LV ejection fraction (EF), LV basal circumferential/radial strain, and mid-radial strain were significantly lower in patients with ATTRwt compared with patients with ATTRm. There was no significant difference between the two groups in the other parameters. In the receiver-operating characteristic curve analysis, LVEF and LV basal mean radial strain were the best parameters for distinguishing between the two groups.

CONCLUSION

Patients with ATTRwt are characterized by lower LVEF, LV basal, and LV mid-radial strains compared with patients with ATTRm. LVEF and LV radial strain are useful in distinguishing between ATTRwt and ATTRm when TTR has been proved in biopsy specimens.

Prognostic implication of relative regional strain ratio in cardiac amyloidosis

OBJECTIVE

Cardiac amyloidosis (CA) is a rapidly progressive disease that portends poor prognosis. Our objective was to evaluate the prognostic impact of relative regional strain ratio (RRSR, a measure of the relative apical sparing of longitudinal strain (LS)) in CA.

METHODS

This is a retrospective study evaluating 97 patients with CA from 2004 to 2013. Patients were included if they met criteria for CA based on endomyocardial biopsy or advanced imaging criteria coupled with either extracardiac biopsy or genetic analysis. Baseline clinical and imaging data were collected and compared between light-chain amyloidosis (AL) (n=59) and transthyretin amyloidosis (ATTR) (n=38) subtypes. RRSR was defined as the average apical LS divided by the sum of the average mid and basal LS values. A Cox proportional hazards model was used to assess the effects of clinical and echocardiographic characteristics, including RRSR, on the outcome of time to death or heart transplantation.

RESULTS

Despite younger age, the AL subtype had a statistically significant association with the composite outcome as compared with ATTR (p=0.022). Log-transformed RRSR was independently associated with the composite outcome at 5 years (HR 2.45 (1.36 to 4.40), p=0.003). Patients with low ejection fraction and high RRSR had the worst prognosis. In multivariable analysis, RRSR remained predictive of the primary outcome (p=0.018). Addition of covariates related to systolic function (global LS and ejection fraction) to the model attenuated this effect.

CONCLUSIONS

High RRSR is adversely prognostic in patients with cardiac amyloid. This novel tool is both diagnostic and prognostic and may have implications in management and suitability for treatment.

Causes and Consequences of Longitudinal LV Dysfunction Assessed by 2D Strain Echocardiography in Cardiac Amyloidosis

OBJECTIVES

The aim of this study was to compare left ventricular longitudinal strain (LS) evaluated by 2-dimensional echocardiography with cardiac magnetic resonance (CMR) in cardiac amyloidosis (CA), establish correlations between histological and imaging findings, and assess the prognostic usefulness of LS measurement and CMR.

BACKGROUND

CA is a condition with a poor prognosis due chiefly to 3 forms of amyloidosis: light-chain amyloidosis (AL), hereditary transthyretin (M-TTR), and wild-type transthyretin (WT-TTR). Two-dimensional echocardiography measurement of LS has been reported to detect early left ventricular systolic dysfunction. The pathophysiological underpinnings, regional distribution, and prognostic significance of LS in CA are unclear.

METHODS

All patients underwent echocardiography, and 53 underwent CMR. The native hearts of the 3 patients who received heart transplants were subjected to histological examination. For each of the 17 left ventricular segments in the American Heart Association model, we evaluated LS, late gadolinium enhancement (LGE) by CMR, and cardiac amyloid deposition. Univariate and multivariate analyses were performed at 6 months to identify variables associated with major adverse cardiac events (MACE).

RESULTS

We studied 79 patients with CA; 26 had AL, 36 M-TTR, and 17 WT-TTR. Mean LS was -10 ± 4%. Both LS and amyloid deposits showed a basal-to-apical gradient. The mean LS and number of segments with LGE were similar across the 3 CA types. LS correlated with LGE and amyloid burden (r = 0.72). LGE was seen in the 6 basal segments in all WT-TTR patients. During the median follow-up of 11 months (range 4 to 17 months), 36 (46%) patients experienced MACE. Independent predictors of MACE were apical LS (cutoff, -14.5%), N-terminal pro-B-type natriuretic peptide (cutoff, 4,000 ng/l), and New York Heart Association functional class III to IV heart failure.

CONCLUSIONS

Basal-to-apical LS abnormalities are similar across CA types and reflect the amyloid burden. Apical LS independently predicts MACE.

Natural history and therapy of TTR-cardiac amyloidosis: emerging disease-modifying therapies from organ transplantation to stabilizer and silencer drugs

Transthyretin-cardiac amyloidoses (ATTR-CA) are an underdiagnosed but increasingly recognized cause of heart failure. Extracellular deposition of fibrillary proteins into tissues due to a variety of inherited transthyretin mutations in ATTRm or due to advanced age in ATTRwt eventually leads to organ failure. In the heart, amyloid deposition causes diastolic dysfunction, restrictive cardiomyopathy with progressive loss of systolic function, arrhythmias, and heart failure. While traditional treatments have consisted of conventional heart failure management and supportive care for systemic symptoms, numerous disease-modifying therapies have emerged over the past decade. From organ transplantation to transthyretin stabilizers (diflunisal, tafamidis, AG-1), TTR silencers (ALN-ATTR02, ISIS-TTR(Rx)), and degraders of amyloid fibrils (doxycycline/TUDCA), the potential for effective transthyretin amyloid therapy is greater now than ever before. In light of these multiple agents under investigation in human clinical trials, clinicians should be familiar with the systemic cardiac amyloidoses, their differing pathophysiology, natural histories, and unique treatment strategies.

Cardiovascular magnetic resonance for amyloidosis

Cardiac involvement drives the prognosis and treatment in systemic amyloid. Echocardiography, the mainstay of current cardiac imaging, defines cardiac structure and function. Echocardiography, in conjunction with clinical phenotype, electrocardiogram and biomarkers (brain natriuretic peptide and troponin), provides an assessment of the likelihood and extent of cardiac involvement. Two tests are transforming our understanding of cardiac amyloidosis, bone tracer scanning and cardiovascular magnetic resonance (CMR). CMR provides a "second opinion" on the heart's structure and systolic function with better accuracy and more precision than echocardiography but is unable to assess diastolic function and is not as widely available. Where CMR adds unique advantages is in evaluating myocardial tissue characterisation. With administration of contrast, the latest type of late gadolinium enhancement imaging (phase-sensitive inversion recovery sequence) is highly sensitive and specific with images virtually pathognomonic for amyloidosis. CMR is also demonstrating that the range of structural and functional changes in cardiac amyloid is broader than traditionally thought. CMR with T1 mapping, a relatively new CMR technique, can measure the amyloid burden and the myocyte response to infiltration (hypertrophy/cell loss) with advantages for tracking change (e.g. the wall thickness can stay the same but the composition can change) over time or during therapy. Such techniques hold great promise for advancing drug development in this arena and providing new prognostic insights. CMR with tissue characterisation is rewriting our understanding of cardiac amyloidosis and may lead to the development of new classification, therapies and prognostic systems.

Noninvasive Identification of ATTRwt Cardiac Amyloid: The Re-emergence of Nuclear Cardiology

More than half of all subjects with chronic heart failure are older adults with preserved ejection fraction (HFpEF). Effective therapy for this condition is yet to be delineated by clinical trials, suggesting that a greater understanding of underlying biologic mechanisms is needed, especially for the purpose of clinical intervention and future clinical trials. Amyloid infiltration of the myocardium is an underappreciated contributing factor to HFpEF that is often caused by misfolded monomers or oligomers of the protein transthyretin. While previously called senile cardiac amyloidosis and traditionally requiring endomyocardial biopsy for diagnosis, advances in our pathophysiologic understanding of this condition, coupled with nuclear imaging techniques using bone isotopes that can diagnose this condition noninvasively and the development of potential therapies, have resulted in a renewed interest in this previously considered "rare" condition. This reviewer focuses on the re-emergence of nuclear cardiology using pyrophosphate agents that hold promise for early, noninvasive identification of affected individuals.

Clinical and echocardiographic characteristics for differentiating between transthyretin-related and light-chain cardiac amyloidoses

Differential diagnosis between transthyretin (TTR) and immunoglobulin light-chain (AL) cardiac amyloidoses is essential due to significantly different prognoses and therapeutic options. Therefore, clinical characteristics of patients with biopsy-proven cardiac amyloidosis were investigated to differentiate TTR from AL amyloidosis. From September 2006 to May 2014, 46 patients were confirmed to have cardiac amyloidosis (TTR, n = 28; AL, n = 18) in our institute. The median age of patients with TTR amyloidosis was 78 years (range 61-90) with 27 (96 %) males, while that of patients with AL amyloidosis was 66 (range 52-76) with 12 (67 %) males. There were no statistically significant differences in echocardiographic findings regarding left ventricular (LV) systolic function or diastolic dysfunction between the two groups. Interestingly, serum brain natriuretic peptide (BNP) levels in patients with AL amyloidosis were significantly higher than those in TTR amyloidosis patients. In contrast, the LV wall was significantly thicker in patients with TTR amyloidosis than in those with AL amyloidosis. Therefore, the ratio of BNP to LV mass index (LVMI) at presentation in AL amyloidosis patients was significantly higher than that in TTR patients (6.7 vs 2.9, p = 0.0006). A BNP-LVMI ratio of less than 3.5 had a diagnostic sensitivity and specificity for TTR amyloidosis of 71 and 83 %, respectively. One-year overall survival was 88.7 % in the patients with TTR amyloidosis and 23.7 % in the patients with AL amyloidosis. Our analysis indicates that the BNP-LVMI ratio, as well as age and sex, may be useful parameters for distinguishing TTR from AL cardiac amyloidosis.

Left ventricular deformation and torsion assessed by speckle-tracking echocardiography in patients with mutated transthyretin-associated cardiac amyloidosis and the effect of diflunisal on myocardial function

Background

Mutated transthyretin-associated (ATTRm) amyloidosis with heart failure is associated with decreased longitudinal left ventricular (LV) myocardial contraction, as measured by strain Doppler echocardiography. We sought to clarify whether speckle-tracking echocardiography (STE) would provide useful information in patients with ATTRm cardiac amyloidosis.

Methods

One hundred twenty-three consecutive patients with ATTRm amyloidosis were divided into 3 groups. Group 1 had no evidence of cardiac involvement (n = 47), group 2 had heart involvement but no congestive heart failure (CHF) and/or serum brain natriuretic peptide (BNP) levels < 100 pg/mL (n = 35), and group 3 had heart involvement and CHF and/or serum BNP levels ≥ 100 pg/mL (n = 41). All patients underwent standard 2-dimensional (2D), Doppler echo, and STE.

Results

By standard 2D and Doppler echo, differences in parameters were only apparent between group 3 and groups 1 and 2. Global circumferential strains by STE at each LV level and LV torsion were different between group 1 and groups 2 and 3, but not between group 2 and group 3. In contrast, global longitudinal LV strain showed significant intergroup differences (− 17.3 ± 2.3%, − 13.3 ± 2.3%, − 9.9 ± 3.3% for groups 1 to 3, respectively, P < 0.0001). Radial strain also showed significant intergroup differences for each basal LV segment. Among 41 patients who could have been followed up after 1 year, 34 patients with diflunisal treatment had shown improvement in apical rotation and torsion without deterioration in multidirectional strains.

Conclusion

ATTRm cardiac amyloidosis is characterized by progressive impairment in longitudinal and basal LV radial function when global circumferential shortening and torsion remain unchanged.

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.

Visual Assessment of Relative Apical Sparing Pattern Is More Useful Than Quantitative Assessment for Diagnosing Cardiac Amyloidosis in Borderline or Mildly Increased Left Ventricular Wall Thickness

BACKGROUND

Relative apical sparing pattern of longitudinal strain (RapSP-LS) was suggested in advanced cardiac amyloidosis (CA). It is unclear whether it is present in less advanced CA.

METHODS AND RESULTS

Patients with presumptive diagnosis of CA and mean left ventricular wall thickness (LVWT) ≤14 mm were recruited. Apart from RapSP-LS visually identified, relative apical longitudinal strain index (RapLSI) was defined as [average apical LS/(average basal LS+average mid-ventricle LS)]. Among 119 patients included, 47 were finally diagnosed with CA. RapLSI was higher in the CA group compared to other causes of increased mean LVWT (P<0.001), but with a significant range of overlap noted. In contrast, RapSP-LS visually assessed was noted in most CA patients (31/47, 66.0%) except in those with preserved LV ejection fraction, normal LVWT, and mildly decreased global LS, suggesting least advanced CA. On multivariate analysis of the added diagnostic role of RapSP-LS or RapLSI on top of clinical, electrocardiographic, and conventional echocardiographic parameters, addition of RapLSI produced only borderline increase in area under the curve of the multivariate model (P=0.05), whereas addition of RapSP-LS significantly increased it (P<0.001).

CONCLUSIONS

Visual identification of RapSP-LS is useful in terms of added diagnostic value compared with quantitative calculation of RapLSI. Its clinical application, however, should be used with caution in patients with less advanced CA.

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.

Prognostic significance of semiautomatic quantification of left ventricular long axis shortening in systemic light-chain amyloidosis

AIMS

To assess left ventricular long axis shortening (LAS) in patients with AL amyloidosis as a potential predictor for outcome.

METHODS AND RESULTS

We performed a de novo echocardiographic analysis of LAS in 120 patients with biopsy-proven AL amyloidosis evaluated at first presentation before specific treatment. Additionally, 47 control subjects were analyzed retrospectivly. LAS was measured using a semiautomatic tissue motion annular displacement software algorithm (TMAD). LAS was significantly better than ejection fraction (EF) (p < 0.0001) and M-mode-derived mitral annular plane systolic excursion (MAPSE) (p < 0.05) discriminating AL patients from control subjects, while being non-inferior compared to tissue Doppler-derived peak systolic mitral annular velocity. One year outcome analysis in patients with AL amyloidosis showed that LAS remained the only significant echocardiographic parameter (HR:0.76; p < 0.005) in a multivariable Cox regression model of echocardiographic values. In a comprehensive clinical model, LAS (HR:0.72, p < 0.0001), cardiac troponin-T (HR:2.86, p < 0.01) and free light chain difference (HR:1.00; p < 0.05) were independently associated with the outcome. Assessment of LAS led to a significant integrated discrimination improvement and offered incremental information compared to EF and biomarkers. The cut-off value for LAS discriminating the endpoint was 5.8%.

CONCLUSION

LAS was an independent predictor of survival within the first year and offers incremental information in patients with AL amyloidosis evaluated prior to specific treatment.

Asp58Ala is the predominant mutation of the TTR gene in Korean patients with hereditary transthyretin-related amyloidosis

Hereditary transthyretin (TTR)-related amyloidosis (ATTR) seems to be a rare autosomal-dominant inherited form of systemic amyloidosis. Studies indicate considerable heterogeneity in the disease's presentation and genotype; however, there is little data from Korea, where the prevalence of hereditary ATTR is very low. In this study, we investigated the phenotypic and genotypic spectra of hereditary ATTR in Korea. Direct sequencing analysis was performed to detect TTR gene mutations in amyloidosis patients whose results of TTR immunohistochemical staining were positive or equivocal. Clinical presentation was categorized as exclusively cardiac, exclusively neurologic, or mixed phenotype. Of 12 genetic tests performed, seven were positive for TTR mutations. D58A (c.173A>C) was the most common mutation in this study (57%, 4/7). The majority of those patients with hereditary ATTR had the mixed phenotype (86%, 6/7). The patients with D58A mutation had older ages of disease onset (median, 61 years vs. 42 years; P = 0.08), and a higher incidence of gastrointestinal involvement (75% vs. 0%; P = 0.03) than those with other identified TTR mutations. A significant male predominance was also noted in this study (P = 0.01).

Echocardiographic and biohumoral characteristics in patients with AL and TTR amyloidosis at diagnosis

BACKGROUND

Few studies have analyzed the clinical and echocardiographic differences between light-chain (AL) and transthyretin (TTR) amyloidosis.

HYPOTHESIS

The aim of the present research was to compare, in a real-world setting, the clinical and echocardiographic profiles of these kinds of amyloidosis, at the time of diagnosis, using new-generation echocardiography.

METHODS

Seventy-nine patients with AL and 48 patients with TTR amyloidosis were studied.

RESULTS

According to the criterion of mean left ventricular (LV) thickness >12 mm, 45 AL (C-AL) and all TTR patients had cardiac amyloidotic involvement, whereas 34 AL patients did not. TTR patients had increased right ventricular (RV) and LV chambers with increased RV and LV wall thickness and reduced LV ejection fraction and fractional shortening. Furthermore, TTR patients showed lower N-terminal pro Brain Natriuretic Peptide concentrations and New York Heart Association functional class when compared with C-AL.

CONCLUSIONS

Our data show that at time of first diagnosis, TTR patients have a more advanced amyloidotic involvement of the heart, despite less severe symptoms and biohumoral signs of heart failure. We can hypothesize that we observed different diseases at different stages. In fact, AL amyloidosis is a multiorgan disease with quick progression rate, that becomes rapidly symptomatic, whereas TTR amyloidosis might have a slow progression rate and might remain poorly symptomatic for a greater amount of time.

Global longitudinal strain and global circumferential strain by speckle-tracking echocardiography and feature-tracking cardiac magnetic resonance imaging: comparison with left ventricular ejection fraction

BACKGROUND

Left ventricular (LV) ejection fraction (EF) is a routine clinical standard to assess cardiac function. Global longitudinal strain (GLS) and global circumferential strain (GCS) have emerged as important LV functional measures. The objective of this study was to determine the relationships of GLS and GCS by speckle-tracking echocardiography and featuring-tracking cardiac magnetic resonance (CMR) to CMR EF as a standard of reference in the same patients.

METHODS

A total of 73 consecutive patients aged 55 ± 15 years clinically referred for both CMR and echocardiography (EF range, 8%-78%) were studied. Routine steady-state free precession CMR images were prospectively analyzed offline using feature-tracking software for LV GLS, GCS, volumes, and EF. GLS was averaged from three standard longitudinal views and GCS from the mid-LV short-axis plane. Echocardiographic speckle-tracking was used from the similar imaging planes for GLS, GCS, LV volumes, and EF.

RESULTS

Feature-tracking CMR strain was closely correlated with speckle-tracking strain in the same patients: GLS, r = -0.87; GCS, r = -0.92 (P < .0001). End-diastolic and end-systolic volumes and EF by feature-tracking CMR were significantly correlated with standard manual tracing of multiple CMR short-axis images (r = 0.97, r = 0.98, and r = 0.97, P < .0001 for all). GLS and GCS by echocardiography and CMR feature-tracking were closely correlated with standard CMR EF: r = -0.85 and r = -0.95, respectively (P < .001). Global strain measures (in absolute values) were correlated with EF using the formula EF = 3(GLS) + 8% or EF = 2.5(GCS) + 8%.

CONCLUSIONS

GLS and GCS by feature-tracking CMR analysis was a rapid means to obtain myocardial strain similar to speckle-tracking echocardiography. GLS and GCS were closely correlated with CMR EF in this patient series and may play a role in the clinical assessment of LV function.

Cardiac Amyloid - An Update

Cardiac amyloidosis is a condition characterised by rapidly progressive heart failure and poor prognosis. The two main subtypes, immunoglobulin light chains (AL) and transthyretin (ATTR), have been investigated extensively in recent years. Cardiac imaging has advanced with the widespread use of cardiac MRI with late gadolinium enhancement imaging and newer techniques including T1 mapping to quantify amyloid burden. Nuclear imaging has developed as a highly accurate method to confirm cardiac amyloid deposits non-invasively with very high sensitivity in ATTR amyloidosis. Despite advances in imaging, cardiac biopsy remains the gold standard diagnostic test to confirm and type amyloidosis. Hereditary ATTR amyloidosis of V122I type has been the focus of important studies in the past year, due to the high prevalence of the amyloidogenic allele in patients of African descent. Recent research concluded a significant number of Afro-Caribbean heart failure patients are likely to have undiagnosed cardiac amyloidosis. Misdiagnosis may lead to inappropriate treatment with potentially harmful 'standard' heart failure medications with no evidence base in amyloidosis. Treatment options have, until recently, been limited but cardiac amyloidosis is the focus of novel therapeutic regimes. New insights into the pathophysiological mechanisms resulting in disease have suggested exciting targets for drug therapy.

Noninvasive detection of cardiac involvement in patients with hereditary transthyretin associated amyloidosis using cardiac magnetic resonance imaging: a prospective study

BACKGROUND

Most of the studies that described cardiac amyloidosis using cardiac magnetic resonance (CMR) imaging refer to patients with primary light chain (AL) amyloidosis. The goal of this study was to evaluate cardiac involvement in patients with hereditary transthyretin associated (ATTR) amyloidosis and asymptomatic carriers and its relationships with clinical symptoms and genotype, using CMR imaging.

METHODS AND RESULTS

Fifty-three patients with hereditary ATTR amyloidosis and 14 asymptomatic carriers were included in this study. Morphological, functional and late gadolinium enhancement (LGE) findings were noted on CMR images. A positive LGE suggesting cardiac amyloidosis was detected in 60% of patients. The pattern of LGE was diffuse, focal and circumferential in 32, 26 and 2% of patients, respectively. The inferior basal segment was the most frequently involved (93%) in case of focal involvement. Diffuse pattern was exclusively encountered in patients with cardiac symptoms. Nineteen percent of patients with isolated neurological symptoms and 20% of subjects without left ventricular wall thickening exhibited cardiac abnormalities on CMR.

CONCLUSION

Cardiac involvement can be detected in patients with hereditary ATTR amyloidosis with isolated neurological symptoms and without left ventricular wall thickening, suggesting that CMR could be useful in detecting preclinical cardiac amyloidosis.

The mosaic of the cardiac amyloidosis diagnosis: role of imaging in subtypes and stages of the disease

Cardiac amyloidosis is a rare, infiltrative cardiomyopathy that presents with thickened ventricular walls and progressive heart failure. The morphological findings and clinical features are shared with many other diseases (i.e. hypertrophic cardiomyopathy, 'athlete's heart,' Fabry disease, and hypertensive cardiomyopathy), and misdiagnosis occurs frequently. Cardiologists have many instruments that can help reach a correct diagnosis in a relatively short time. As tiles of a mosaic are placed to create an image, thoughtful and smart use of the different diagnostic tools available allows the opportunity to identify amyloid infiltration of the myocardium. When the myocardium is involved, prognosis is poor, so identification of its involvement is crucial for disease management. The diagnostic process begins with an accurate evaluation of clinical elements and includes cardiovascular imaging (echocardiography, magnetic resonance, and nuclear medicine), electrocardiography, serological assays, and myocardial biopsy; only the appropriate integration of these instruments can reveal the diagnosis to an expert physician. The latest improvements in non-invasive diagnostic techniques with increased diagnostic power have reduced the need for biopsy.

Disease-specific differences of left ventricular rotational mechanics between cardiac amyloidosis and hypertrophic cardiomyopathy

Left ventricular (LV) twist (LVT) and untwisting (LVUT) rate are global and thorough parameters of LV function. The aim of the present study was to investigate the differences in LV rotational mechanics between patients with cardiac amyloidosis (CA) and hypertrophic cardiomyopathy (HCM). Twenty consecutive patients with CA, 20 consecutive patients with HCM, and 20 consecutive subjects without evidence of structural heart disease were included. Cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) imaging was performed to evaluate biventricular function, LV mass index, and presence/extent of LGE. Feature-tracking analysis was applied to LV basal and apical short-axis images to determine peak LVT, time to peak LVT, peak LVUT rate, and time to peak LVUT rate. Peak LVT and peak LVUT rate were significantly impaired in patients with CA compared with controls (P < 0.05 for both). In patients with HCM, peak LVT was increased (P < 0.05) compared with controls, whereas peak LVUT rate was preserved (P > 0.05). Time to peak LVUT rate was significantly prolonged in patients with CA and in patients with HCM compared with controls (ANOVA P < 0.001). At multivariate analysis, age (P = 0.007), LV ejection fraction (P = 0.035) and extent of LGE (P < 0.001) were independently related to peak LVT, and LV mass index (P = 0.015) and extent of LGE (P = 0.004) were independently related to peak LVUT rate, whereas extent of LGE (P < 0.001) was the only variable independently related to time to peak LVUT rate. In conclusion, CA and HCM have specific behavior of LV rotational mechanics. The extent of LGE significantly influences the LV rotational mechanics.