Differentiating cardiac amyloidosis and hypertrophic cardiomyopathy by use of three-dimensional speckle tracking echocardiography

Deep Learning-Derived Myocardial Strain

BACKGROUND

Echocardiographic strain measurements require extensive operator experience and have significant intervendor variability. Creating an automated, open-source, vendor-agnostic method to retrospectively measure global longitudinal strain (GLS) from standard echocardiography B-mode images would greatly improve post hoc research applications and may streamline patient analyses.

OBJECTIVES

This study was seeking to develop an automated deep learning strain (DLS) analysis pipeline and validate its performance across multiple applications and populations.

METHODS

Interobserver/-vendor variation of traditional GLS, and simulated effects of variation in contour on speckle-tracking measurements were assessed. The DLS pipeline was designed to take semantic segmentation results from EchoNet-Dynamic and derive longitudinal strain by calculating change in the length of the left ventricular endocardial contour. DLS was evaluated for agreement with GLS on a large external dataset and applied across a range of conditions that result in cardiac hypertrophy.

RESULTS

In patients scanned by 2 sonographers using 2 vendors, GLS had an intraclass correlation of 0.29 (95% CI: -0.01 to 0.53, P = 0.03) between vendor measurements and 0.63 (95% CI: 0.48-0.74, P < 0.001) between sonographers. With minor changes in initial input contour, step-wise pixel shifts resulted in a mean absolute error of 3.48% and proportional strain difference of 13.52% by a 6-pixel shift. In external validation, DLS maintained moderate agreement with 2-dimensional GLS (intraclass correlation coefficient [ICC]: 0.56, P = 0.002) with a bias of -3.31% (limits of agreement: -11.65% to 5.02%). The DLS method showed differences (P < 0.0001) between populations with cardiac hypertrophy and had moderate agreement in a patient population of advanced cardiac amyloidosis: ICC was 0.64 (95% CI: 0.53-0.72), P < 0.001, with a bias of 0.57%, limits of agreement of -4.87% to 6.01% vs 2-dimensional GLS.

CONCLUSIONS

The open-source DLS provides lower variation than human measurements and similar quantitative results. The method is rapid, consistent, vendor-agnostic, publicly released, and applicable across a wide range of imaging qualities.

Limitations of apical sparing pattern in cardiac amyloidosis: a multicentre echocardiographic study

AIMS

Although impaired left ventricular (LV) global longitudinal strain (GLS) with apical sparing is a feature of cardiac amyloidosis (CA), its diagnostic accuracy has varied across studies. We aimed to determine the ability of apical sparing ratio (ASR) and most common echocardiographic parameters to differentiate patients with confirmed CA from those with clinical and/or echocardiographic suspicion of CA but with this diagnosis ruled out.

METHODS AND RESULTS

We identified 544 patients with confirmed CA and 200 controls (CTRLs) as defined above (CTRL patients). Measurements from transthoracic echocardiograms were performed using artificial intelligence software (Us2.AI, Singapore) and audited by an experienced echocardiographer. Receiver operating characteristic curve analysis was used to evaluate the diagnostic performance and optimal cut-offs for the differentiation of CA patients from CTRL patients. Additionally, a group of 174 healthy subjects (healthy CTRL) was included to provide insight on how patients and healthy CTRLs differed echocardiographically. LV GLS was more impaired (-13.9 ± 4.6% vs. -15.9 ± 2.7%, P < 0.0005), and ASR was higher (2.4 ± 1.2 vs. 1.7 ± 0.9, P < 0.0005) in the CA group vs. CTRL patients. Relative wall thickness and ASR were the most accurate parameters for differentiating CA from CTRL patients [area under the curve (AUC): 0.77 and 0.74, respectively]. However, even with the optimal cut-off of 1.67, ASR was only 72% sensitive and 66% specific for CA, indicating the presence of apical sparing in 32% of CTRL patients and even in 6% healthy subjects.

CONCLUSION

Apical sparing did not prove to be a CA-specific biomarker for accurate identification of CA, when compared with clinically similar CTRLs with no CA.

Position Statement on the Use of Myocardial Strain in Cardiology Routines by the Brazilian Society of Cardiology's Department Of Cardiovascular Imaging - 2023

Central Illustration : Position Statement on the Use of Myocardial Strain in Cardiology Routines by the Brazilian Society of Cardiology's Department Of Cardiovascular Imaging - 2023 Proposal for including strain in the integrated diastolic function assessment algorithm, adapted from Nagueh et al.67 Am: mitral A-wave duration; Ap: reverse pulmonary A-wave duration; DD: diastolic dysfunction; LA: left atrium; LASr: LA strain reserve; LVGLS: left ventricular global longitudinal strain; TI: tricuspid insufficiency. Confirm concentric remodeling with LVGLS. In LVEF, mitral E wave deceleration time < 160 ms and pulmonary S-wave < D-wave are also parameters of increased filling pressure. This algorithm does not apply to patients with atrial fibrillation (AF), mitral annulus calcification, > mild mitral valve disease, left bundle branch block, paced rhythm, prosthetic valves, or severe primary pulmonary hypertension.

Preservation of Circumferential and Radial Left Ventricular Function as a Mitigating Mechanism for Impaired Longitudinal Strain in Early Cardiac Amyloidosis

BACKGROUND

In patients with cardiac amyloidosis (CA), left ventricular ejection fraction (LVEF) is frequently preserved, despite commonly reduced global longitudinal strain (GLS). We hypothesized that nonlongitudinal contraction may initially serve as a mitigating mechanism to maintain cardiac output and studied the relationship between global circumferential (GCS) and radial (GRS) strain with LVEF and extracellular volume (ECV), a marker of amyloid burden.

METHODS

Patients with CA who underwent cardiac magnetic resonance (CMR; n = 140, 70.7 ± 11.5 years, 66% male) or echocardiography (n = 67, 71 ± 13 years, 66% male) and normal controls (CMR, n = 20; echocardiography, n = 45) were retrospectively identified, and GCS, GLS, and GRS were quantified using feature-tracking CMR or speckle-tracking echocardiography and compared between CA patients with preserved and reduced LVEF (CAHFpEF, CAHFrEF) and controls. The prevalence of impaired strain (magnitudes <2.5th percentile of the controls) was compared between CAHFpEF and CAHFrEF and between ECV quartiles.

RESULTS

While echocardiography-derived GLS was impaired in both CAHFpEF (-13.4% ± 3.1%, P < .003) and CAHFrEF (-9.1% ± 3.2%, P < .003), compared with controls (-20.8% ± 2.4%), GCS was more impaired in CAHFrEF compared with both controls (-15.6% ± 5.0% vs -32.3% ± 3.3%, P < .003) and CAHFpEF (-30.4% ± 5.7%, P < .003) and did not differ between CAHFpEF and controls (P = .24). The prevalence of abnormal CMR-derived GCS (P < .0001) and GRS (P < .0001) but not GLS (P = .054) varied significantly across ECV quartiles.

CONCLUSIONS

Among CA patients with preserved LVEF, preserved GCS and GRS, despite near-universally impaired GLS, may be explained by an initial predominantly subendocardial involvement, where mostly longitudinal fibers are located. If confirmed in future studies, these findings may facilitate identification of patients with early stages of CA, when treatments may be most effective.

Anderson-Fabry disease cardiomyopathy: an update on epidemiology, diagnostic approach, management and monitoring strategies

Anderson-Fabry disease (AFD) is an X-linked lysosomal storage disorder caused by deficient activity of the enzyme alpha-galactosidase. While AFD is recognized as a progressive multi-system disorder, infiltrative cardiomyopathy causing a number of cardiovascular manifestations is recognized as an important complication of this disease. AFD affects both men and women, although the clinical presentation typically varies by sex, with men presenting at a younger age with more neurologic and renal phenotype and women developing a later onset variant with more cardiovascular manifestations. AFD is an important cause of increased myocardial wall thickness, and advances in imaging, in particular cardiac magnetic resonance imaging and T1 mapping techniques, have improved the ability to identify this disease non-invasively. Diagnosis is confirmed by the presence of low alpha-galactosidase activity and identification of a mutation in the GLA gene. Enzyme replacement therapy remains the mainstay of disease modifying therapy, with two formulations currently approved. In addition, newer treatments such as oral chaperone therapy are now available for select patients, with a number of other investigational therapies in development. The availability of these therapies has significantly improved outcomes for AFD patients. Improved survival and the availability of multiple agents has presented new clinical dilemmas regarding disease monitoring and surveillance using clinical, imaging and laboratory biomarkers, in addition to improved approaches to managing cardiovascular risk factors and AFD complications. This review will provide an update on clinical recognition and diagnostic approaches including differentiation from other causes of increased ventricular wall thickness, in addition to modern strategies for management and follow-up.

Machine learning algorithms to automate differentiating cardiac amyloidosis from hypertrophic cardiomyopathy

Cardiac amyloidosis has a poor prognosis, and high mortality and is often misdiagnosed as hypertrophic cardiomyopathy, leading to delayed diagnosis. Machine learning combined with speckle tracking echocardiography was proposed to automate differentiating two conditions. A total of 74 patients with pathologically confirmed monoclonal immunoglobulin light chain cardiac amyloidosis and 64 patients with hypertrophic cardiomyopathy were enrolled from June 2015 to November 2018. Machine learning models utilizing traditional and advanced algorithms were established and determined the most significant predictors. The performance was evaluated by the receiver operating characteristic curve (ROC) and the area under the curve (AUC). With clinical and echocardiography data, all models showed great discriminative performance (AUC > 0.9). Compared with logistic regression (AUC 0.91), machine learning such as support vector machine (AUC 0.95, p = 0.477), random forest (AUC 0.97, p = 0.301) and gradient boosting machine (AUC 0.98, p = 0.230) demonstrated similar capability to distinguish cardiac amyloidosis and hypertrophic cardiomyopathy. With speckle tracking echocardiography, the predictive performance of the voting model was similar to that of LightGBM (AUC was 0.86 for both), while the AUC of XGBoost was slightly lower (AUC 0.84). In fivefold cross-validation, the voting model was more robust globally and superior to the single model in some test sets. Data-driven machine learning had shown admirable performance in differentiating two conditions and could automatically integrate abundant variables to identify the most discriminating predictors without making preassumptions. In the era of big data, automated machine learning will help to identify patients with cardiac amyloidosis and timely and effectively intervene, thus improving the outcome.

Differential diagnosis of common etiologies of left ventricular hypertrophy using a hybrid CNN-LSTM model

Differential diagnosis of left ventricular hypertrophy (LVH) is often obscure on echocardiography and requires numerous additional tests. We aimed to develop a deep learning algorithm to aid in the differentiation of common etiologies of LVH (i.e. hypertensive heart disease [HHD], hypertrophic cardiomyopathy [HCM], and light-chain cardiac amyloidosis [ALCA]) on echocardiographic images. Echocardiograms in 5 standard views (parasternal long-axis, parasternal short-axis, apical 4-chamber, apical 2-chamber, and apical 3-chamber) were obtained from 930 subjects: 112 with HHD, 191 with HCM, 81 with ALCA and 546 normal subjects. The study population was divided into training (n = 620), validation (n = 155), and test sets (n = 155). A convolutional neural network-long short-term memory (CNN-LSTM) algorithm was constructed to independently classify the 3 diagnoses on each view, and the final diagnosis was made by an aggregate network based on the simultaneously predicted probabilities of HCM, HCM, and ALCA. Diagnostic performance of the algorithm was evaluated by the area under the receiver operating characteristic curve (AUC), and accuracy was evaluated by the confusion matrix. The deep learning algorithm was trained and verified using the training and validation sets, respectively. In the test set, the average AUC across the five standard views was 0.962, 0.982 and 0.996 for HHD, HCM and CA, respectively. The overall diagnostic accuracy was significantly higher for the deep learning algorithm (92.3%) than for echocardiography specialists (80.0% and 80.6%). In the present study, we developed a deep learning algorithm for the differential diagnosis of 3 common LVH etiologies (HHD, HCM and ALCA) by applying a hybrid CNN-LSTM model and aggregate network to standard echocardiographic images. The high diagnostic performance of our deep learning algorithm suggests that the use of deep learning can improve the diagnostic process in patients with LVH.

Diagnostic Accuracy of Bone Scintigraphy for the Histopathological Diagnosis of Cardiac Transthyretin Amyloidosis-A Retrospective Austrian Multicenter Study

We aimed to ascertain the real-world diagnostic accuracy of bone scintigraphy in combination with free light chain (FLC) assessment for transthyretin (ATTR) cardiac amyloidosis (CA) using the histopathological diagnosis derived from endomyocardial biopsy (EMB) as a reference standard. We retrospectively analyzed 102 patients (22% women) with suspected CA from seven Austrian amyloidosis referral centers. The inclusion criteria comprised the available results of bone scintigraphy, FLC assessment, and EMB with histopathological analysis. ATTR and AL were diagnosed in 60 and 21 patients (59%, 21%), respectively, and concomitant AL and ATTR was identified in one patient. The specificity and positive predictive value (PPV) of Perugini score ≥ 2 for ATTR CA were 95% and 96%. AL was diagnosed in three out of 31 patients (10%) who had evidence of monoclonal proteins and a Perugini score ≥ 2. When excluding all patients with detectable monoclonal proteins (n = 62) from analyses, the PPV of Perugini score ≥ 2 for ATTR CA was 100% and the NPV of Perugini score < 2 for ATTR CA was 79%. Conclusively, ATTR CA can be diagnosed non-invasively in the case of a Perugini score ≥ 2 and an unremarkable FLC assessment. However, tissue biopsy is mandatory in suspected CA in any other constellation of non-invasive diagnostic work-up.

Echocardiographic Differentiation of Pericardial Constriction and Left Ventricular Restriction

PURPOSE OF REVIEW

Overlapping hemodynamics in constrictive pericarditis (CP) and restrictive cardiomyopathy (RCM) often pose difficulties in establishing accurate diagnosis. Echocardiography is the first-line imaging modality used for this purpose, but no single echocardiographic parameter is sufficiently robust for distinguishing between the two conditions. The newer developments may improve the diagnostic accuracy of echocardiography in this setting.

RECENT FINDINGS

Recent studies have validated multiparametric algorithms, based on conventional echocardiographic parameters, which enable high sensitivity and specificity for distinguishing between CP and RCM. In addition, myocardial deformation analysis using speckle-tracking echocardiography has revealed distinct pattern of abnormalities in the two conditions. CP is characterized by impaired left ventricular apical rotation with relatively preserved longitudinal strain, esp. of ventricular and atrial septum. In contrast, RCM results in global and marked impairment of left ventricular longitudinal strain with initially preserved circumferential mechanics. Combining multiple echocardiographic parameters into step-wise algorithms and incorporation of myocardial deformation analysis help improve the diagnostic accuracy of echocardiography for distinguishing between CP and RCM. The use of machine-learning may allow easy integration of a wide range of echocardiographic and clinical parameters to permit accurate, automated diagnosis, with less dependence on the user expertise.

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

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

Integration of imaging and circulating biomarkers in heart failure: a consensus document by the Biomarkers and Imaging Study Groups of the Heart Failure Association of the European Society of Cardiology

Circulating biomarkers and imaging techniques provide independent and complementary information to guide management of heart failure (HF). This consensus document by the Heart Failure Association (HFA) of the European Society of Cardiology (ESC) presents current evidence-based indications relevant to integration of imaging techniques and biomarkers in HF. The document first focuses on application of circulating biomarkers together with imaging findings, in the broad domains of screening, diagnosis, risk stratification, guidance of treatment and monitoring, and then discusses specific challenging settings. In each section we crystallize clinically relevant recommendations and identify directions for future research. The target readership of this document includes cardiologists, internal medicine specialists and other clinicians dealing with HF patients.

Transthyretin Cardiac Amyloidosis and Novel Therapies to Treat This Not-so-rare Cause of Cardiomyopathy

Transthyretin cardiac amyloidosis (ATTR-CA) is typically a late-onset disease caused by the deposit of transthyretin amyloid fibrils throughout the heart. When this occurs, various cardiac sequelae can develop, including hypotension, conduction abnormalities, and valvular lesions. The cardiomyopathy caused by ATTR-CA (ATTR-CM) has proven difficult to treat. Until recently, symptomatic management was the only therapeutic option, and many therapies used to treat congestive heart failure were ineffective or even detrimental to patients with ATTR-CM. In addition, treatment was limited to heart and liver transplantation. As a result, prognosis was poor. Recently, a few drug therapies have come to light as potential treatment modalities for ATTR-CM, most notably tafamidis, sold under the brand names Vyndaqel and Vyndamax. After the phase III Transthyretin Amyloidosis Cardiomyopathy trial displayed the drug's efficacy, it was given breakthrough therapy designation and was approved by the Food and Drug Administration on May 6, 2019, for the treatment of ATTR-CA. This novel therapy, as well as various other therapies in the pipeline, such as inotersen and patisiran, provide hope where, until recently, there was little. Unfortunately, the exorbitant cost of these new therapies may present a barrier to long-term treatment for some patients. However, by further improving diagnostic algorithms and incorporating these new treatments into our existing therapeutic modalities, patients with ATTR-CA should be able to live far longer than previously expected. Finally, further research combining these novel treatment modalities must be done, as they may prove to be additive or even synergistic in their treatment of ATTR amyloidosis.

CMR-based T1-mapping offers superior diagnostic value compared to longitudinal strain-based assessment of relative apical sparing in cardiac amyloidosis

Cardiac amyloidosis (CA) is an infiltrative disease. In the present study, we compared the diagnostic accuracy of cardiovascular magnetic resonance (CMR)-based T1-mapping and subsequent extracellular volume fraction (ECV) measurement and longitudinal strain analysis in the same patients with (a) biopsy-proven cardiac amyloidosis (CA) and (b) hypertrophic cardiomyopathy (HCM). N = 30 patients with CA, N = 20 patients with HCM and N = 15 healthy control patients without relevant cardiac disease underwent dedicated CMR studies. The CMR protocol included standard sequences for cine-imaging, native and post-contrast T1-mapping and late-gadolinium-enhancement. ECV measurements were based on pre- and post-contrast T1-mapping images. Feature-tracking analysis was used to calculate 3D left ventricular longitudinal strain (LV-LS) in basal, mid and apical short-axis cine-images and to assess the presence of relative apical sparing. Receiver-operating-characteristic analysis revealed an area-under-the-curve regarding the differentiation of CA from HCM of 0.984 for native T1-mapping (p < 0.001), of 0.985 for ECV (p < 0.001) and only 0.740 for the "apical-to-(basal + midventricular)"-ratio of LV-LS (p = 0.012). A multivariable logistical regression analysis showed that ECV was the only statistically significant predictor of CA when compared to the parameter LV-LS or to the parameter "apical-to-(basal + midventricular)" LV-RLS-ratio. Native T1-mapping and ECV measurement are both superior to longitudinal strain measurement (with assessment of relative apical sparing) regarding the appropriate diagnosis of CA.

Diagnostic score of cardiac involvement in AL amyloidosis

AIMS

Early diagnosis of cardiac involvement is a key issue in the management of AL amyloidosis. Our objective was to establish a diagnostic score of cardiac involvement in AL amyloidosis and to compare it with the current consensus criteria [i.e. left ventricular hypertrophy >12 mm and N-terminal pro b-type natriuretic peptide (NT-proBNP) >332 ng/L].

METHODS AND RESULTS

We carried out a prospective and multicenter study on AL amyloidosis patients who underwent cardiac evaluation including clinical examination, electrocardiography (ECG), cardiac biomarkers, transthoracic echocardiography (TTE), and cardiac magnetic resonance imaging (CMR). Cardiac involvement was based on CMR and/or endomyocardial biopsy. In a derivation cohort of 114 patients (82 with cardiac involvement), the highest diagnostic accuracy was observed with NT-proBNP and troponin blood levels, TTE-derived global longitudinal strain (LS), and apical to basal LS gradient. By using multivariate analysis, we established a diagnostic score including global LS ≥-17% (1 point), apical/(basal + median) LS ≥0.90 (1 point), and troponin T >35 ng/L (1 point). A score >1 was associated with sensitivity of 94% and specificity of 97%, an area under the curve of 0.98 [95% confidence interval (CI) 0.93-0.99] as well as a net reclassification index of 0.39 (95% CI 0.28-0.46) when compared with consensus criteria. In a validation cohort of 73 AL amyloidosis patients, the area under the receiver operating characteristic curve of the diagnostic score was 0.97 (95% CI 0.90-0.99).

CONCLUSION

Combining T troponin blood levels and two echo-derived strain parameters leads to very high accuracy for diagnosing cardiac involvement in AL amyloid patients.

Fibrosis in hypertrophic cardiomyopathy: role of novel echo techniques and multi-modality imaging assessment

Hypertrophic cardiomyopathy (HCM) represents one of the primary cardiomyopathies and may lead to heart failure and sudden cardiac death. Among various histologic features of the disease examined, assessment of myocardial fibrosis may offer valuable information, since it may be considered the common nominator for all HCM connected complications. Late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) has emerged as the reference noninvasive method for visualizing and quantifying myocardial fibrosis in patients with HCM. T1 mapping, a promising new CMR technique, may provide an advantage over conventional LGE-CMR, by permitting a more valid quantification of diffuse fibrosis. On the other hand, echocardiography offers a significantly more portable, affordable, and easily accessible solution for the study of fibrosis. Various echocardiographic techniques ranging from integrated backscatter and contrast-enhanced ultrasound to two- (2D) or three-dimensional (3D) deformation and shear wave imaging may offer new insights into substrate characterization in HCM. The aim of this review is to describe thoroughly all different modalities that may be used in everyday clinical practice for HCM fibrosis evaluation (with special focus on echocardiographic techniques), to concisely present available evidence and to argue in favor of multi-modality imaging application. It is essential to understand that the role of various imaging modalities is not competitive but complementary, since the information provided by each one is necessary to illuminate the complex pathophysiologic pathways of HCM, offering a personalized approach and treatment in every patient.

Ventricular systolic dysfunction with and without altered myocardial contractility: Clinical value of echocardiography for diagnosis and therapeutic decision-making

The inability of one of the two or both ventricles to contract normally and expel sufficient blood to meet the functional demands of the body results from a complex interplay between intrinsic abnormalities and extracardiac factors that limit ventricular pump function and is a major cause for heart failure (HF). Even if impaired myocardial contractile function was the primary cause for ventricular dysfunction, with the progression of systolic dysfunction, additionally developed diastolic dysfunction can also contribute to the severity of HF. Although at the first sight, the diagnosis of systolic HF appears quite easy because it is usually defined by reduction of the ejection fraction (EF), in reality this issue is far more complex because ventricular pumping performance depends not only on myocardial contractility, but also largely on loading conditions (preload and afterload), being also influenced by valvular function, ventricular interdependence, pericardial constraint, synchrony of ventricular contrac-tion and heart rhythm. Conventional echocardiography (ECHO) combined with new imaging techniques such as tissue Doppler and tissue tracking can detect early subclinical alteration of ventricular systolic function. However, no single ECHO parameter reveals alone the whole picture of systolic dysfunction. Multiparametric ECHO evaluation and the use of integrative approaches using ECHO-parameter combinations which include also the ventricular loading conditions appeared particularly useful especially for differentiation between primary (myocardial damage-induced) and secondary (hemodynamic overload-induced) systolic dysfunction. This review summarizes the available evidence on the usefulness and limitations of comprehensive evaluation of LV and RV systolic function by using all the currently available ECHO techniques.

Comparison of tissue tracking assessment by cardiovascular magnetic resonance for cardiac amyloidosis and hypertrophic cardiomyopathy

BACKGROUND

Administration of gadolinium-contrast can cause problems in cardiac amyloidosis (CA) patients with impaired renal function.

PURPOSE

To compare patterns of cardiovascular magnetic resonance tissue tracking (CMR-TT) for CA and hypertrophic cardiomyopathy (HCM) and to assess the feasibility of CMR-TT to distinguish between these diseases without administration of gadolinium-contrast.

MATERIAL AND METHODS

Included were 54 patients with biopsy-proven CA, 40 patients with HCM, and 30 healthy people. We calculated strain ratio of apex to base (SRAB) in the left ventricle (LV) using radial (R), circumferential (C), and longitudinal (L) strain from CMR-TT. The LV ejection fraction (LVEF) and the ratio of septal to posterior wall at basal level were also calculated. Late gadolinium enhancement (LGE) image analysis was performed for differential diagnosis. Area under the receiver operating characteristic curve (AUC) comparisons were used.

RESULTS

All SRAB values were significantly different between CA and HCM (all P < 0.001). AUC values for parameters were 0.806 for LVEF, 0.815 for ratio of wall thickness, 0.944 for the LGE pattern, 0.898 for SRAB_R, 0.880 for SRAB_C, and 0.805 for SRAB_L. AUCs for the LGE pattern were significantly higher than for LVEF, ratio of wall thickness and SRAB_L (all P < 0.008). No significant differences were seen between AUCs for the LGE pattern, SRAB_R, and SRAB_C (all P > 0.109).

CONCLUSION

SRAB_R and SRAB_C were reliable parameters for distinguishing between CA and HCM.

Cardiac amyloidosis: non-invasive diagnosis

Cardiac amyloidosis is an infiltrative disease which requires a high degree of clinical suspicion for appropriate diagnosis. Early diagnosis and the definition of the type of amyloidosis play a key role in the early treatment and prognosis of this disease. In this context, the use of cardiac biomarkers such as troponins and NT-proBNT associated with analysis by multimodality imaging methods like echocardiographic techniques such as strain, nuclear medicine, and cardiovascular resonance imaging have an increasing role in patients with cardiac amyloidosis. This article details the role of non-invasive diagnostic methods in patients with cardiac amyloidosis.

A review of current trends in three-dimensional analysis of left ventricular myocardial strain

Three-dimensional (3D) left ventricular (LV) myocardial strain measurements using transthoracic 3D echocardiography speckle tracking analysis have several advantages over two-dimensional (2D) LV strain measurements, because 3D strain values are derived from the entire LV myocardium, yielding more accurate estimates of global and regional LV function. In this review article, we summarize the current status of 3D LV myocardial strain. Specifically, we describe how 3D LV strain analysis is performed. Next, we compare characteristics of 2D and 3D strain, and we explain validation of 3D strain measurements, feasibility and measurement differences between 2D and 3D strain, reference values of 3D strain, and its applications in several clinical scenarios. In some parts of this review, we used a meta-analysis to draw reliable conclusions. We also describe the added value of 3D over 2D strain in several specific pathologies and prognoses. Finally, we discuss novel techniques using 3D strain and suggest its future directions.

The diagnostic challenges of cardiac amyloidosis: A practical approach to the two main types

Systemic amyloidosis of the immunoglobulin light-chain (AL) or transthyretin type (ATTR) is a multisystem protein deposition disease that often involves the heart. Delays in diagnosis are very common and can have detrimental consequences on patient outcomes. Because both major types can now be distinguished quickly and treated effectively, clear approaches are required. There have been advances in radioisotope scintigraphy, monoclonal protein testing and mass spectrometry for typing that need coordinated application. We have entered an era in which rapid diagnosis and ready therapy will save lives, therefore we must develop coherent approaches to this multisystem disease. The prognosis for AL has improved significantly with the incorporation of novel agents such as proteasome inhibitors, immunomodulators and monoclonal antibodies against plasma cells. Multiple independent studies have demonstrated the efficacy of these agents in AL, though tolerability can become an issue with dose reductions required in many cases. Median overall survival for patients achieving complete responses after stem cell transplant and consolidation exceeds a decade. The prognosis for ATTR, both age-related wild-type (ATTRwt) and hereditary due to variants of transthyretin (ATTRv), has improved as well due to the availability of the stabilizer tafamidis and the RNA-interference agents patisiran and inotersen. In both AL and ATTR, with elimination or suppression of the pathologic amyloid-forming protein, symptomatic involvement of the heart, kidneys and peripheral nervous system can improve as well. In this review, we present the current state of diagnosing and treating the two major types of systemic amyloidosis, emphasizing the coherent clinical application of the new tools and treatments. Implementation of the approaches we provide will enable rapid identification of amyloid type and rational selection of therapy.

Diagnosing cardiac amyloidosis in every-day practice: A practical guide for the cardiologist

Cardiac amyloidosis (CA) has emerged as a previously underestimated cause of heart failure and mortality. Underdiagnosis resulted mainly from unawareness of the true disease prevalence and the non-specific symptoms of the disease. CA results from extracellular deposition of misfolded protein fibrils, commonly derived from transthyretin (ATTR) or immunoglobulin light chains (AL). A significant proportion of older patients with heart failure and other extracardiac manifestations suffer from ATTR-CA, whereas AL-CA is still considered a rare disease. This article provides an overview of CA with a special focus on current and emerging diagnostic modalities. Furthermore, we provide a diagnostic algorithm for the evaluation of patients with suspected CA in every-day practice.

Advances in the diagnosis and treatment of transthyretin amyloidosis with cardiac involvement

Amyloidosis is caused by extracellular deposition of insoluble abnormal fibrils constituted by misfolded proteins, which can modify tissue anatomy and hinder the function of multiple organs including the heart. Amyloidosis that can affect the heart includes mostly systemic amyloidosis (amyloid light chain, AL) and transthyretin amyloidosis (ATTR). The latter can be acquired in elderly patients (ATTRwt), or be inherited in younger individuals (ATTRm). The diagnosis is demanding given the high phenotypic heterogeneity of the disease. Therefore, "red flags," which are suggestive features giving support to diagnostic suspicion, are extremely valuable. However, the lack of broad awareness among clinicians represents a major obstacle for early diagnosis and treatment of ATTR. Furthermore, recent implementation of noninvasive diagnostic techniques has revisited the need for endomyocardial biopsy (EMB). In fact, unlike AL amyloidosis, which requires tissue confirmation and typing for diagnosis, ATTR can now be diagnosed noninvasively with the combination of bone scintigraphy and the absence of a monoclonal protein. Securing the correct diagnosis is pivotal for the newly available therapeutic options targeting both ATTRm and ATTRwt, and are directed to either stabilization of the abnormal protein or the reduction of the production of transthyretin. The purpose of this article is to review the contemporary aspects of diagnosis and management of transthyretin amyloidosis with cardiac involvement, summarizing also the recent therapeutic advances with tafamidis, patisiran, and inotersen.

Echocardiographic tissue imaging evaluation of myocardial characteristics and function in cardiomyopathies

Current echocardiography techniques have allowed more precise assessment of cardiac structure and function of the several types of cardiomyopathies. Parameters derived from echocardiographic tissue imaging (ETI)-tissue Doppler, strain, strain rate, and others-are extensively used to provide a framework in the evaluation and management of cardiomyopathies. Generally, myocardial function assessed by ETI is depressed in all types of cardiomyopathies, non-ischemic dilated cardiomyopathy (DCM) in particular. In hypertrophic cardiomyopathy (HCM), ETI is useful to identify subclinical disease in family members of HCM, to differentiate HCM from other conditions causing cardiac hypertrophy and to predict cardiac events. ETI also for HCM allows addressing the mechanism behind left ventricular outflow tract obstruction and its improvement after therapeutic options. ETI provides cardiac amyloidosis with unique and specific findings such as "apical sparing." Nevertheless, ETI does not seem to provide as much information amenable to histological findings as recently emerging techniques of cardiac magnetic resonance imaging. This review introduces usefulness of ETI and some other ultrasound techniques for detecting clinical and subclinical characteristics of cardiomyopathies, focusing on DCM, HCM, and cardiac amyloidosis.

Cardiac Amyloidosis: Current Diagnostic Strategies Using Multimodality Imaging

Amyloidosis is a systemic disorder in which abnormal amyloid proteins deposit in body organs, leading to organ dysfunction and death. Cardiac amyloid deposition, causing a sort of restrictive cardiomyopathy and associated with increased risk of mortality. Most cases of cardiac amyloidosis are of either light chain or transthyretin type. Early and accurate diagnosis of cardiac amyloidosis may improve outcomes. However, diagnosis requires systematic approach including electrocardiography and biomarkers when encountered suspicious candidate. Diagnosis by multimodality noninvasive imaging have been substantially studied and established for differentiation from subtypes. Recent advance in the treatment of amyloidosis offers therapeutic monitoring and prognosis.

Multiparametric Echocardiography Scores for the Diagnosis of Cardiac Amyloidosis

OBJECTIVES

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Cardiac amyloidosis: in search of the ideal diagnostic tool

BACKGROUND

Cardiac amyloidosis (CA) is due to amyloid deposition in the myocardium. Transthyretin (ATTR) and light-chain (AL) amyloidosis are the main types of CA. Here, we present the clinical and imaging findings in patients with CA and discuss the controversies with the aim of finding the ideal diagnostic tool.

METHODS

Ten patients suspected of having CA on the basis of electrocardiographic (ECG) and echocardiographic findings were evaluated via cardiovascular magnetic resonance imaging (CMR; 1.5 T) using cine, late gadolinium enhancement (LGE), T1, T2 mapping, and extracellular volume fraction. N‑terminal pro-B-type natriuretic peptide (NT-proBNP) levels were also assessed in all patients.

RESULTS

All ten patients had an echocardiogram suggestive of CA. The CMR study documented ventricular hypertrophy leading to small ventricular volumes, as assessed by echocardiography. Diffuse subendocardial LGE, supporting the diagnosis of CA, was identified in all except one patient, who had subepicardial LGE due to myocarditis that was verified by endomyocardial biopsy (EMB). Right ventricular (RV) involvement was identified in four of the ten patients, whose condition deteriorated rapidly over the next 6 months. The NT-proBNP levels were >332 pg/ml in all except two patients. Light-chain amyloidosis was identified via fat tissue biopsy in two patients and through renal biopsy in one patient. In two patients with positive technetium-99m, EMB confirmed the diagnosis of ATTR.

CONCLUSION

NT-proBNP may be a sensitive but nonspecific biomarker for assessing CA. However, CMR is the only imaging modality that can assess the pathophysiologic background of cardiac hypertrophy and the severity of CA, irrespective of NT-proBNP level.

AL Amyloidosis: Unfolding a Complex Disease

Light chain (AL) amyloidosis is a rare plasma cell dyscrasia. An estimated 12,000 people live with the disease in the United States. AL amyloidosis occurs from the misfolding of proteins that deposit in organs (heart, kidneys, digestive tract, tongue, lungs, and nervous system), leading to progressive organ damage and impairment of quality of life. The treatment of AL amyloidosis has improved greatly over the past several years, with new treatments currently in development. This article will focus on the pathophysiology, diagnosis, and treatment of AL amyloidosis.

Echocardiography in Infiltrative Cardiomyopathy

Left ventricular (LV) wall thickening can occur due to both physiological and pathological processes. Some LV wall thickening is caused by infiltrative cardiac deposition diseases - rare disorders from both inherited and acquired conditions, with varying systemic manifestations. They portend a poor prognosis and are generally not reversible except in rare circumstances when early diagnosis and treatment may alter the outcome (e.g., Fabry disease). Cardiac involvement is variable and depends on the degree of infiltration and type of infiltrate. These changes often lead to the development of abnormalities in both the relaxation and contractile function of the heart ultimately resulting in heart failure. Echocardiography is generally the first investigation of choice as it is easily available and gives valuable information about the thickness of the ventricular walls as well as systolic and diastolic function. It is also able to identify unique, characteristic features of the disease as well as detecting any haemodynamic sequelae. This review looks at the role of echocardiography in the diagnosis and prognosis of infiltrative cardiac deposition diseases.

Diagnosis of cardiac amyloidosis: a systematic review on the role of imaging and biomarkers

BACKGROUND

Cardiac Amyloidosis (CA) pertains to the cardiac involvement of a group of diseases, in which misfolded proteins deposit in tissues and cause progressive organ damage. The vast majority of CA cases are caused by light chain amyloidosis (AL) and transthyretin amyloidosis (ATTR). The increased awareness of these diseases has led to an increment of newly diagnosed cases each year.

METHODS

We performed multiple searches on MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews. Several search terms were used, such as "cardiac amyloidosis", "diagnostic modalities cardiac amyloidosis" and "staging cardiac amyloidosis". Emphasis was given on original articles describing novel diagnostic and staging approaches to the disease.

RESULTS

Imaging techniques are indispensable to diagnosing CA. Novel ultrasonographic techniques boast high sensitivity and specificity for the disease. Nuclear imaging has repeatedly proved its worth in the diagnostic procedure, with efforts now focusing on standardization and quantification of amyloid load. Because the latter would be invaluable for any staging system, those spearheading research in magnetic resonance imaging of the disease are also trying to come up with accurate tools to quantify amyloid burden. Staging tools are currently being developed and validated for ATTR CA, in the spirit of the acclaimed Mayo Staging System for AL.

CONCLUSION

Cardiac involvement confers significant morbidity and mortality in all types of amyloidosis. Great effort is made to reduce the time to diagnosis, as treatment in the initial stages of the disease is tied to better prognosis. The results of these efforts are highly sensitive and specific diagnostic modalities that are also reasonably cost effective.

Investigation of myocardial dysfunction using three-dimensional speckle tracking echocardiography in a genetic positive hypertrophic cardiomyopathy Chinese family

BACKGROUND

We previously reported four heterozygous missense mutations of MYH7, KCNQ1, MYLK2, and TMEM70 in a single three-generation Chinese family with dual Long QT and hypertrophic cardiomyopathy phenotypes for the first time. However, the clinical course among the family members was various, and the potential myocardial dysfunction has not been investigated.

OBJECTIVES

The objective of this study was to investigate the echocardiographic and electrocardiographic characteristics in a genetic positive Chinese family with hypertrophic cardiomyopathy and further to explore the association between myocardial dysfunction and electric activity, and the identified mutations.

METHODS

A comprehensive echocardiogram - standard two-dimensional Doppler echocardiography and three-dimensional speckle tracking echocardiography - and electrocardiogram were obtained for members in this family.

RESULTS

As previously reported, four missense mutations - MYH7-H1717Q, KCNQ1-R190W, MYLK2-K324E, and TMEM70-I147T - were identified in this family. The MYH7-H1717Q mutation carriers had significantly increased left ventricular mass indices, elevated E/e' ratio, deteriorated global longitudinal stain, but enhanced global circumferential and radial strain compared with those in non-mutation patients (all p<0.05). The KCNQ1-R190W carriers showed significantly prolonged QTc intervals, and the MYLK2-K324E mutation carriers showed inverted T-waves (both p<0.05). However, the TMEM70-I147T mutation carriers had similar echocardiography and electrocardiographic data as non-mutation patients.

CONCLUSIONS

Three of the identified four mutations had potential pathogenic effects in this family: MYH7-H1717Q was associated with increased left ventricular thickness, elevated left ventricular filling pressure, and altered myocardial deformation; KCNQ1-R190W and MYLK2-K324E mutations were correlated with electrocardiographic abnormalities reflected in long QT phenotype and inverted T-waves, respectively.

Right ventricular involvement in transthyretin amyloidosis

BACKGROUND

The extent of right ventricular (RV) involvement in transthyretin amyloidosis (ATTR) is unknown.

OBJECTIVES

This study sought to establish the degree of RV involvement in ATTR amyloidosis, and compare findings with RV involvement in hypertrophic cardiomyopathy (HCM).

METHODS

Forty-two patients with ATTR amyloidosis and echocardiographic evidence of cardiac amyloidosis (cardiac ATTR), 19 ATTR patients with normal left ventricular (LV) wall thickness (non-cardiac ATTR), 25 patients with diagnosed HCM and 30 healthy controls were included in this study. Echocardiographic measurements for conventional parameters, as well as RV global and segmental strain, were recorded.

RESULTS

When comparing RV structure and function between cardiac ATTR amyloidosis and HCM patients, only segmental strain differed between the two groups. In cardiac ATTR amyloidosis, we found an RV apex-to-base strain gradient with highest deformation in the apex. This pattern was reversed in patients with HCM.

CONCLUSIONS

RV involvement is common in cardiac ATTR patients. The present study also detected an RV apical sparing pattern in patients with ATTR cardiomyopathy, similar to what has previously been described for the left ventricle in these patients. This pattern was not seen in HCM patients. Further studies are needed to assess the clinical importance of these findings.

Left Ventricular Myocardial Deformation on Cine MR Images: Relationship to Severity of Disease and Prognosis in Light-Chain Amyloidosis

Purpose To measure left ventricular (LV) myocardial strain with cine magnetic resonance (MR) imaging and a deformable registration algorithm (DRA) and to assess the prognostic value of myocardial strain in patients with light-chain (AL) amyloidosis. Materials and Methods In this prospective study, 78 consecutive patients with AL amyloidosis who underwent contrast material-enhanced cardiac MR imaging were enrolled at West China Hospital. LV myocardial strains and late gadolinium enhancement (LGE) were evaluated. Association between myocardial strain and all-cause mortality was analyzed with the stepwise Cox regression model. Results Global longitudinal strain (GLS) and global circumferential strain (GCS) were significantly lower in the no or nonspecific LGE group compared with the subendocardial LGE and transmural LGE groups (mean GLS, -10% ± 3 [standard deviation] vs -7% ± 3 vs -4% ± 1; P < .001) (mean GCS, -13% ± 3 vs -11% ± 3 vs -7% ± 2; P < .001). GLS and GCS were reduced in patients without clinical cardiac amyloidosis (mean GLS, -13% ± 3 vs -16% ± 2; P = .005) (mean GCS, -16% ± 1 vs -19% ± 2; P = .02). Circumferential and radial strains were impaired in basal segments in accordance with the distribution of LGE. Multivariate Cox analysis revealed that GCS (hazard ratio [HR] = 1.16 per 1% absolute decrease; 95% confidence interval [CI]: 1.03, 1.31; P = .02) and the presence of transmural LGE (HR = 1.75; 95% CI: 1.10, 2.80; P = .02) were independent predictors of all-cause mortality after adjustment for LV ejection fraction, right ventricular ejection fraction, LV mass index, GLS, and global radial strain. Conclusion Strain parameters derived with cine MR imaging-based DRA may be a new noninvasive imaging marker with which to evaluate the extent of cardiac amyloid infiltration and may offer independent prognostic information for all-cause mortality in patients with AL amyloidosis.

Three-dimensional speckle-tracking echocardiography: benefits and limitations of integrating myocardial mechanics with three-dimensional imaging

Three-dimensional (3D) speckle-tracking echocardiography (3DSTE) is an advanced imaging technique designed for left ventricular (LV) myocardial deformation analysis based on 3D data sets. 3DSTE has the potential to overcome some of the intrinsic limitations of two-dimensional STE (2DSTE) in the assessment of complex LV myocardial mechanics, offering additional deformation parameters (such as area strain) and a comprehensive quantitation of LV geometry and function from a single 3D acquisition. Albeit being a relatively young technique still undergoing technological developments, several experimental studies and clinical investigations have already demonstrated the reliability and feasibility of 3DSTE, as well as several advantages of 3DSTE over 2DSTE. This technique has provided new insights into LV mechanics in several clinical fields, such as the objective assessment of global and regional LV function in ischemic and non-ischemic heart diseases, the evaluation of LV mechanical dyssynchrony, as well as the detection of subclinical cardiac dysfunction in cardiovascular conditions at risk of progression to overt heart failure. However, 3DSTE generally requires patient's breathhold and regular rhythm for enabling an ECG-gated multi-beat 3D acquisition. In addition, the measurements, normal limits and cut-off values pertaining to 3D strain parameters are currently vendor-specific and highly dependent on the 3D ultrasound equipment used. Technological advances with improvement in spatial and temporal resolution and a standardized methodology for obtaining vendor-independent 3D strain measurements are expected in the future for a widespread application of 3DSTE in both clinical and research arenas. The purpose of this review is to summarize currently available data on 3DSTE methodology (feasibility, accuracy and reproducibility), strengths and weaknesses with respect to 2DSTE, as well as the main clinical applications and future research priorities of this emerging technology.

Left ventricular short-axis systolic function changes in patients with hypertrophic cardiomyopathy detected by two-dimensional speckle tracking imaging

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a genetic disease was characterised by left ventricular hypertrophy (LVH), myocardial fibrosis, fiber disarray. The short-axis systolic function is important in left ventricle function.

METHODS

Forty one healthy subjects and 37 HCM patients were enrolled for this research. Parasternal short-axis at the basal, middle, and apical levels were acquired by Echocardiography. The peak systolic circumferential strain of the endocardial, the middle and the epicardial layers, the peak systolic radial strain, and the peak systolic rotational degrees at different short-axis levels were measured by 2-dimensional speckle tracking imaging (2D-STI).

RESULTS

The peak systolic circumferential strain of the septum and anterior walls in HCM patients was significantly lower than normal subjects. All of the peak systolic radial strain in HCM patients was significantly lower than normal subjects. The rotational degrees at the base and middle short-axis levels in HCM patients were larger than normal subjects. The interventricular septal thickness in end-diastolic period correlated to the peak systolic circumferential strain of the septum wall.

CONCLUSIONS

The short-axis systolic function was impaired in HCM patients. The peak circumferential systolic strain of the different layers, peak systolic radial strain and rotation degrees of the different short-axis levels detected by 2D-STI are very feasible for assessing the short-axis function in HCM patients.

New Cardiac Imaging Algorithms to Diagnose Constrictive Pericarditis Versus Restrictive Cardiomyopathy

PURPOSE OF REVIEW

Echocardiography is the mainstay in the diagnostic evaluation of constrictive pericarditis (CP) and restrictive cardiomyopathy (RCM), but no single echocardiographic parameter is sufficiently robust to accurately distinguish between the two conditions. The present review summarizes the recent advances in echocardiography that promise to improve its diagnostic performance for this purpose. The role of other imaging modalities such as cardiac computed tomography, magnetic resonance imaging, and invasive hemodynamic assessment in the overall diagnostic approach is also discussed briefly.

RECENT FINDINGS

A recent study has demonstrated improved diagnostic accuracy of echocardiography with integration of multiple conventional echocardiographic parameters in to a step-wise algorithm. Concurrently, the studies using speckle-tracking echocardiography have revealed distinct and disparate patterns of myocardial mechanical abnormalities in CP and RCM with their ability to distinguish between the two conditions. The incorporation of machine-learning algorithms into echocardiography workflow permits easy integration of the wealth of the diagnostic data available and promises to further enhance the diagnostic accuracy of echocardiography. New imaging algorithms are continuously being evolved to permit accurate distinction between CP and RCM. Further research is needed to validate the accuracy of these newer algorithms and to define their place in the overall diagnostic approach for this purpose.

Recent Advances in Cardiovascular Imaging Relevant to the Management of Patients with Suspected Cardiac Amyloidosis

Cardiac amyloidosis is a form of infiltrative cardiomyopathy typically presenting with progressive heart failure. The clinical presentation and morphological findings often overlap with other cardiovascular diseases, and frequently results in misdiagnosis and consequent under-reporting. Cardiovascular imaging is playing an increasingly important diagnostic and prognostic role in this referral population, and is reducing the reliance on endomyocardial biopsy as a confirmatory testing. Advancements across multiple cardiac imaging modalities, including echocardiography, magnetic resonance imaging, nuclear imaging, and computed tomography, are improving diagnostic accuracy and offering novel approaches to sub-type differentiation and prognostication. This review explores recent advancements in cardiac imaging for the diagnosis, typing, and staging of cardiac amyloidosis, with a focus on new and evolving techniques. Emphasis is also placed on the promise of non-invasive cardiac imaging to provide value across the spectrum of this clinical disease, from early disease identification (prior to the development of increased wall thickness) through to markers of advanced disease associated with early mortality.

Left ventricular systolic function changes in hypertrophic cardiomyopathy patients detected by the strain of different myocardium layers and longitudinal rotation

BACKGROUND

Impairment of left ventricular (LV) longitudinal function has an important role in hypertrophic cardiomyopathy (HCM). This research investigated an association between the longitudinal strain of different myocardial layers, longitudinal rotation and the LV systolic function of HCM patients.

METHODS

The research was performed on 36 HCM patients and 36 healthy subjects. The peak systolic longitudinal strain of the subendocardial, midmyocardial, and subepicardial layers was measured using 2-dimensional speckle tracking echocardiography (2D-STE). The apical long-axis and 4- and 2- chamber views were acquired via 2D Doppler echocardiography. The curve of the longitudinal rotation was traced at 17 timepoints in the analysis of 2 cardiac cycles.

RESULTS

Compared with healthy subjects, in HCM patients regional LV peak systolic longitudinal strain was less, not only in hypertrophied LV myocardium, but also in non-hypertrophied myocardium. The rotational degrees of the midmyocardial-septal, apex, and lateral wall of HCM patients were significantly different from that of normal subjects, as follows. In HCM patients, clockwise longitudinal rotation was found. The interventricular septum thickness at end-diastole positively correlated with the peak longitudinal systolic strain of the subendocardial, the midmyocardial, and the subepicardial layers. The area under ROC curve values for subendocardial, midmyocardial and subepicardial layers in HCM patients were 0.923, 0.938, 0.948.

CONCLUSION

In HCM patients, the longitudinal function was damaged, even with normal LV ejection fraction. The peak longitudinal systolic strain of the subendocardial, midmyocardial, and subepicardial layers, and the longitudinal rotation detected by 2D-STE, are very sensitive predictors of systolic function in patients with HCM.

Myocardial Deformation in Cardiac Amyloid Light-chain Amyloidosis: Assessed with 3T Cardiovascular Magnetic Resonance Feature Tracking

Clinically, assessment of myocardial function is essential in patients with amyloid light-chain cardiac amyloidosis (AL-CA) to predict outcome and determine therapeutic approach. The aim of this study was to investigate the feasibility of cardiovascular magnetic resonance (CMR)-derived feature tracking algorithm for assessing left ventricular (LV) myocardial deformation in AL-CA, and to determine if these abnormal myocardial deformation parameters are correlated to impaired LV myocardial microvascular dysfunction. A total of 42 AL-CA patients, including 26 with preserved systolic function and 16 with impaired LVEF, and 35 healthy controls were enrolled and underwent CMR examination. Our result indicated that AL-CA patients had significantly reduced global peak strain (PS) (longitudinal, circumferential, and radial) (all P < 0.05). AL-CA patients with normal LVEF showed preserved longitudinal PS at apical and significantly reduced longitudinal PS at mid and basal segments. By Spearman’s rank correlation analysis, the LV regional radial, circumferential, and longitudinal myocardial deformation values were correlated to myocardial upslope and MaxSI in CA, regardless of LVEF. This study indicated that the abnormal LV myocardial deformation of AL-CA patients can be monitored using feature tracking CMR, even in those with preserved LVEF; and the myocardial deformation was associated with coronary microvascular dysfunction.

Transthyretin Cardiac Amyloidosis in Older Adults: Optimizing Cardiac Imaging to the Corresponding Diagnostic and Management Goal

PURPOSE OF REVIEW

Transthyretin cardiac amyloidosis is increasingly recognized as an important cause of heart failure in older adults. Many cardiac imaging modalities have evolved to evaluate transthyretin cardiac amyloidosis and include 2D echocardiography with tissue Doppler and speckle-strain imaging, nuclear scintigraphy, cardiac magnetic resonance imaging, and positron emission tomography. The purpose of this review is to highlight the optimal selection of advanced cardiac imaging techniques with corresponding diagnostic goals including raising suspicion, making an early diagnosis, and subtyping transthyretin cardiac amyloid, as well as management goals including assessment of ventricular impairment, prognosticating, and monitoring disease progression. Potential benefits of optimizing cardiac imaging in the elderly patient with transthyretin cardiac amyloidosis may include enhanced and earlier diagnosis and refined long-term management.

RECENT FINDINGS

Advances in cardiac imaging techniques are changing diagnostic and management algorithms for transthyretin cardiac amyloidosis.

SUMMARY

With a new era of novel therapeutics, enhanced recognition, and earlier diagnosis approaching, selecting the appropriate non-invasive cardiac imaging modality will be essential for optimal care in the elderly patient with transthyretin cardiac amyloidosis.

Strain Imaging Echocardiography: What Imaging Cardiologists Should Know

Despite recent advances in clinical imaging, echocardiography remains as the most accessi-ble and reliable noninvasive. Since knowledge of left ventricular systolic function remains so critically important in determining prognosis; every effort should be made to prevent subjective estimations. The advent of strain imaging echocardiography now offers a readily available and portable imaging tool that not only offers an objective characterization of myocardial dynamics; but also allows for early detection of subclinical left ventricular dysfunction. This review outlines the basic concepts of strain imaging to better understand the mechanism of myocardial function as well their applicability in the least common cardiac diagnosis among current clinical practice.

Speckle Tracking and Transthyretin Amyloid Cardiomyopathy

Background

Amyloidosis is a disease caused by deposits of insoluble fibrils in extracellular spaces. The most common type of familial amyloidosis is mediated by mutation of transthyretin, especially Val30Met. Symptoms and ejection fraction decrease may occur in cardiac amyloidosis only in case of poor prognosis. Myocardial strain detected by two-dimensional speckle tracking echocardiography can indicate changes in myocardial function at early stages of the disease.

Objective

To determine the accuracy of left ventricular longitudinal strain by two-dimensional speckle tracking echocardiography in patients with familial amyloidosis caused by Val30Met transthyretin mutation.

Methods

Eighteen consecutive patients, carriers of transthyretin mutation, were evaluated by two-dimensional speckle tracking echocardiography, by which myocardial strain curves were obtained, following the American Society of Echocardiography recommendations.

Results

Patients were divided into three groups: 1- Val30Met with cardiac amyloidosis; 2-Val30Met with extracardiac amyloidosis; 3 - Val30Met without evidence of disease. As the three groups were compared by the Mann-Whitney test, we found a statistically significant difference between groups 1 and 2 in the mean longitudinal tension (p=0.01), mean basal longitudinal strain (p=0.014); in mean longitudinal tension and mean longitudinal strain between groups 1 and 3 (p=0.005); and in the ratio of longitudinal strain of apical septum segment to longitudinal strain of basal septum (p=0.041) between groups 2 and 3.

Conclusion

Left ventricular longitudinal strain detected by two-dimensional speckle tracking echocardiography is able to diagnose left ventricular dysfunction in early stages of familial amyloidosis caused by transthyretin Val30Met mutation.

Anterior Aortic Plane Systolic Excursion: A Novel Indicator of Transplant-Free Survival in Systemic Light-Chain Amyloidosis

BACKGROUND

Anterior aortic plane systolic excursion (AAPSE) was evaluated in the present pilot study as a novel echocardiographic indicator of transplant-free survival in patients with systemic light-chain amyloidosis.

METHODS

Eighty-nine patients with light-chain amyloidosis were included in the post-hoc analysis. A subgroup of 54 patients with biopsy-proven cardiac amyloid infiltration were compared with 41 healthy individuals to evaluate the discriminative ability of echocardiographic findings. AAPSE is defined as the systolic excursion of the anterior aortic margin. To quantify AAPSE, the M-mode cursor was placed on the aortic valve plane in parasternal long-axis view at end-diastole. Index echocardiography had been performed before chemotherapy. Median follow-up duration was 2.4 years. The primary combined end point was heart transplantation or overall death.

RESULTS

Mean AAPSE was 14 ± 2 mm in healthy individuals (mean age=57 ± 10 years; 56% men; BMI=25 ± 4 kg/m²). AAPSE < 11 mm separated patients from age-, gender-, and BMI-matched control subjects with 93% sensitivity and 97% specificity. Median transplant-free survival of patients with AAPSE < 5 mm was 0.7 versus 4.8 years (P = .0001). AAPSE was an independent indicator of transplant-free survival in multivariate Cox regression (echocardiographic model: hazard ratio=0.72 [P = .03]; biomarker model: hazard ratio=0.62 [P = .0001]). Sequential regression analysis suggested incremental power of AAPSE as a marker of transplant-free survival. An ejection fraction-based model with an overall χ² value of 22.8 was improved by the addition of log NT-proBNP (χ² = 32.6, P < .005), troponin-T (χ² = 39.6, P < .01), and AAPSE (χ² = 54.0, P < .0001).

CONCLUSIONS

AAPSE is suggested as an indicator of transplant-free survival in patients with systemic light-chain amyloidosis. AAPSE provided significant incremental value to established staging models.