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

Epidemiological Changes in Transthyretin Cardiac Amyloidosis: Evidence from In Vivo Data and Autoptic Series

Cardiac amyloidosis is an infiltrative disease that causes progressive myocardial impairment secondary to amyloid fibril deposition in the extracellular space of the myocardium. Many amyloid precursors, including transthyretin protein, are known to determine cardiac damage by aggregating and precipitating in cardiac tissue. Transthyretin cardiac amyloidosis may be either caused by rare genetic mutations of the transthyretin gene in the hereditary variant, or may arise as a consequence of age-related mechanisms in the acquired form. Although it has been labeled as a rare disease, in recent years, transthyretin cardiac amyloidosis has stood out as an emerging cause of aortic stenosis, unexplained left ventricular hypertrophy and heart failure with preserved ejection fraction, particularly in the elderly. Indeed, the integration of data deriving from both in vivo imaging techniques (whose advancement in the last years has allowed to achieve an easier and more accessible non-invasive diagnosis) and forensic studies (showing a prevalence of amyloid deposition in cardiac tissue of elderly patients up to 29%) suggests that cardiac amyloidosis is a more common disease than traditionally considered. Thanks to all the improvements in non-invasive diagnostic techniques, along with the development of efficacious therapies offering improvements in survival rates, transthyretin cardiac amyloidosis has been transformed from an incurable and infrequent condition to a relatively more diffuse and treatable disease, which physicians should take into consideration in the differential diagnostic processes in daily clinical practice.

Role of endogenous T1ρ and its dispersion imaging in differential diagnosis of cardiac amyloidosis

BACKGROUND

Cardiovascular magnetic resonance (CMR) has demonstrated excellent performance in the diagnosis of cardiac amyloidosis (CA). However, misdiagnosis occasionally occurs because the morphological and functional features of CA are non-specific. This study was performed to determine the value of non-contrast CMR T1ρ in the diagnosis of CA.

METHODS

This prospective study included 45 patients with CA, 30 patients with hypertrophic cardiomyopathy (HCM), and 10 healthy controls (HCs). All participants underwent cine (whole heart), T1ρ mapping, pre- and post-contrast T1 mapping imaging (three slices), and late gadolinium enhancement using a 3T whole-body magnetic resonance imaging system. All participants underwent T1ρ at two spin-locking frequencies: 0 and 298 Hz. Extracellular volume (ECV) maps were obtained using pre- and post-contrast T1 maps. The myocardial T1ρ dispersion map, termed myocardial dispersion index (MDI), was also calculated. All parameters were measured in the left ventricular myocardial wall. Participants in the HC group were scanned twice on different days to assess the reproducibility of T1ρ measurements.

RESULTS

Excellent reproducibility was observed upon evaluation of the coefficient of variation between two scans (T1ρ [298 Hz]: 3.1%; T1ρ [0 Hz], 2.5%). The ECV (HC: 27.4 ± 2.8% vs HCM: 32.6 ± 5.8% vs CA: 46 ± 8.9%; p < 0.0001), T1ρ [0 Hz] (HC: 35.8 ± 1.7 ms vs HCM: 40.0 ± 4.5 ms vs CA: 51.4 ± 4.4 ms; p < 0.0001) and T1ρ [298 Hz] (HC: 41.9 ± 1.6 ms vs HCM: 48.8 ± 6.2 ms vs CA: 54.4 ± 5.2 ms; p < 0.0001) progressively increased from the HC group to the HCM group, and then the CA group. The MDI progressively decreased from the HCM group to the HC group, and then the CA group (HCM: 8.8 ± 2.8 ms vs HC: 6.1 ± 0.9 ms vs CA: 3.4 ± 2.1 ms; p < 0.0001). For differential diagnosis, the combination of MDI and T1ρ [298 Hz] showed the greatest sensitivity (98.3%) and specificity (95.5%) between CA and HCM, compared with the native T1 and ECV.

CONCLUSION

The T1ρ and MDI approaches can be used as non-contrast CMR imaging biomarkers to improve the differential diagnosis of patients with CA.

World Heart Federation Consensus on Transthyretin Amyloidosis Cardiomyopathy (ATTR-CM)

Transthyretin amyloid cardiomyopathy (ATTR-CM) is a progressive and fatal condition that requires early diagnosis, management, and specific treatment. The availability of new disease-modifying therapies has made successful treatment a reality. Transthyretin amyloid cardiomyopathy can be either age-related (wild-type form) or caused by mutations in the TTR gene (genetic, hereditary forms). It is a systemic disease, and while the genetic forms may exhibit a variety of symptoms, a predominant cardiac phenotype is often present. This document aims to provide an overview of ATTR-CM amyloidosis focusing on cardiac involvement, which is the most critical factor for prognosis. It will discuss the available tools for early diagnosis and patient management, given that specific treatments are more effective in the early stages of the disease, and will highlight the importance of a multidisciplinary approach and of specialized amyloidosis centres. To accomplish these goals, the World Heart Federation assembled a panel of 18 expert clinicians specialized in TTR amyloidosis from 13 countries, along with a representative from the Amyloidosis Alliance, a patient advocacy group. This document is based on a review of published literature, expert opinions, registries data, patients' perspectives, treatment options, and ongoing developments, as well as the progress made possible via the existence of centres of excellence. From the patients' perspective, increasing disease awareness is crucial to achieving an early and accurate diagnosis. Patients also seek to receive care at specialized amyloidosis centres and be fully informed about their treatment and prognosis.

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.

AL Amyloidosis for Cardiologists: Awareness, Diagnosis, and Future Prospects: JACC: CardioOncology State-of-the-Art Review

Amyloid light chain (AL) amyloidosis is a rare, debilitating, often fatal disease. Symptoms of cardiomyopathy are common presenting features, and patients often are referred to cardiologists. Cardiac amyloid infiltration is the leading predictor of death. However, the variable presentation and perceived rarity of the disease frequently lead to delay in suspecting amyloidosis as a cause of heart failure, leading to misdiagnoses and a marked delay in diagnosis, with devastating consequences for the patient. A median time from symptom onset to correct diagnosis of about 2 years is often too long when median survival from diagnosis for patients with AL amyloidosis and cardiomyopathy is 4 months to 2 years. The authors highlight the challenges to diagnosis, identify gaps in the current knowledge, and summarize novel treatments on the horizon to raise awareness about the critical need for early recognition of symptoms and diagnosis of AL amyloidosis aimed at accelerating treatment and improving outcomes for patients.

Prevalence and diagnostic value of extra-left ventricle echocardiographic findings in transthyretin-related cardiac amyloidosis

BACKGROUND

Cardiac amyloidosis (CA) is cardiomyopathy with a hypertrophic phenotype characterised by diffuse deposition of anomalous fibrillar proteins in the extracellular matrix.

OBJECTIVES

To evaluate the prevalence and diagnostic value of extra left ventricle echocardiographic findings in patients with left ventricular (LV) hypertrophic phenotype and amyloid deposition.

METHODS

A group of 146 patients with LV thickness ≥15 mm were enrolled: 70 patients who received a definite diagnosis of sarcomeric hypertrophic cardiomyopathy (HCM group) and 76 patients with transthyretin cardiac amyloidosis (CA group). Echocardiographic analysis of crista terminalis (CriT), atrio-ventricular plane (AVP), mitro-aortic lamina (MAL), anterior ascending aortic wall, interatrial septum (IAS), Eustachian valve (EusV) and coumadin ridge (CouR) was performed in all patients, and these structures were compared among the two groups.

RESULTS

CA group showed significantly higher dimensions of CriT, IAS, CouR, AVP, MAL and IAS compared to the HCM group. The logistic analysis showed that LV EF, LV septal thickness, CriT presence, CriT area, MAL and IAS were all predictors of CA in univariate analyses. The stepwise multivariate analysis showed independent predictors of CA: CriT area, MAL and LVEF. According to areas under the receiver operating characteristic curves the best cut-off values to determine CA were identified (IAS > 9 mm, MAL > 7 mm, CriT > 9 mm²). Among these 3 independent predictors, IAS > 9 mm had the best specificity (96%) and positive predictive value (93%) in identifying CA.

CONCLUSIONS

evidence of extra left ventricle sites of amyloid deposition is a frequent finding in CA. In the context of hypertrophic phenocopies, an increased thickness of IAS, and/or CT and/or MAL should suggest a diagnosis of transthyretin CA.

Cardiac amyloidosis characterization by kinetic model fitting on [18F]florbetaben PET images

OBJECTIVE

To evaluate the feasibility of kinetic modeling-based approaches from [18F]-Flobetaben dynamic PET images as a non-invasive diagnostic method for cardiac amyloidosis (CA) and to identify the two AL- and ATTR-subtypes.

METHODS AND RESULTS

Twenty-one patients with diagnoses of CA (11 patients with AL-subtype and 10 patients with ATTR-subtype of CA) and 15 Control patients with no-CA conditions underwent PET/CT imaging after [18F]Florbetaben bolus injection. A two-tissue-compartment (2TC) kinetic model was fitted to time-activity curves (TAC) obtained from left ventricle wall and left atrium cavity ROIs to estimate kinetic micro- and macro-parameters. Combinations of kinetic parameters were evaluated with the purpose of distinguishing Control subjects and CA patients, and to correctly label the last ones as AL- or ATTR-subtype. Resulting sensitivity, specificity, and accuracy for Control subjects were: 0.87, 0.9, 0.89; as far as CA patients, the sensitivity, specificity, and accuracy were respectively 0.9, 1, and 0.97 for AL-CA patients and 0.9, 0.92, 0.97 for ATTR-CA patients.

CONCLUSION

Pharmacokinetic analysis based on a 2TC model allows cardiac amyloidosis characterization from dynamic [18F]Florbetaben PET images. Estimated model parameters allows to not only distinguish between Control subjects and patients, but also between AL- and ATTR-amyloid patients.

Prognostic Implication of Longitudinal Changes of Left Ventricular Global Strain After Chemotherapy in Cardiac Light Chain Amyloidosis

Aim

Cardiac involvement is the main prognostic determinant in AL amyloidosis. We sought to determine the prognostic significance of longitudinal change of left ventricular (LV) global longitudinal strain (GLS) in cardiac light chain (AL) amyloidosis patients undergoing chemotherapy.

Methods and Result

We retrospectively investigated 117 cardiac AL amyloidosis patients who underwent chemotherapy from 2005 to 2019. All patients underwent comprehensive 2D conventional transthoracic echocardiography at baseline and after completion of first-line chemotherapy. Speckle tracking analysis of images was performed offline. Absolute value of LV GLS was expressed as [LV GLS] and change of [LV GLS] after chemotherapy was expressed as Δ [LV GLS]. Clinical outcomes including cardiac response and all-cause mortality were analyzed.Baseline clinical and echocardiographic parameters were similar in patients with and without CR. Δ [LV GLS] significantly differed between the CR and non-CR groups (0.4 ± 2.8% in the CR group vs. -0.6 ± 2.5% in the non-CR group, P-value = 0.046). Δ [LV GLS] showed satisfactory predictive performance for all-cause mortality (cut-off value = 0.8%, AUC 0.643, 95% CI [0.537-0.748]). Adding Δ [LV GLS] to the Mayo stage + pre-chemotherapy [LV GLS] model showed incremental prognostic value (C-index: 0.637 vs. 0.708; Relative Integrated Discrimination Index 0.07, P-value = 0.003; Net Reclassification Improvement 0.54, P-value < 0.001). Δ [LV GLS] showed good correlation with cardiac response (AUC 0.820, 95% CI [0.737-0.904]).

Conclusion

In cardiac amyloidosis patients who underwent chemotherapy, longitudinal change of [LV GLS] after chemotherapy showed significant association with overall survival as well as cardiac response.

Multimodality Imaging in the Evaluation and Prognostication of Cardiac Amyloidosis

Cardiac amyloidosis (CA) is an infiltrative cardiomyopathy resulting from deposition of misfolded immunoglobulin light chains (AL-CA) or transthyretin (ATTR-CA) proteins in the myocardium. Survival varies between the different subtypes of amyloidosis and degree of cardiac involvement, but accurate diagnosis is essential to ensure initiation of therapeutic interventions that may slow or potentially prevent morbidity and mortality in these patients. As there are now effective treatment options for CA, identifying underlying disease pathogenesis is crucial and can be guided by multimodality imaging techniques such as echocardiography, magnetic resonance imaging, and nuclear scanning modalities. However, as use of cardiac imaging is becoming more widespread, understanding optimal applications and potential shortcomings is increasingly important. Additionally, certain imaging modalities can provide prognostic information and may affect treatment planning. In patients whom imaging remains non-diagnostic, tissue biopsy, specifically endomyocardial biopsy, continues to play an essential role and can facilitate accurate and timely diagnosis such that appropriate treatment can be started. In this review, we examine the multimodality imaging approach to the diagnosis of CA with particular emphasis on the prognostic utility and limitations of each imaging modality. We also discuss how imaging can guide the decision to pursue tissue biopsy for timely diagnosis of CA.

Assessing Cardiac Amyloidosis Subtypes by Unsupervised Phenotype Clustering Analysis

BACKGROUND

Cardiac amyloidosis (CA) is a set of amyloid diseases with usually predominant cardiac symptoms, including light-chain amyloidosis (AL), hereditary variant transthyretin amyloidosis (ATTRv), and wild-type transthyretin amyloidosis (ATTRwt). CA are characterized by high heterogeneity in phenotypes leading to diagnosis delay and worsened outcomes.

OBJECTIVES

The authors used clustering analysis to identify typical clinical profiles in a large population of patients with suspected CA.

METHODS

Data were collected from the French Referral Center for Cardiac Amyloidosis database (Hôpital Henri Mondor, Créteil), including 1,394 patients with suspected CA between 2010 and 2018: 345 (25%) had a diagnosis of AL, 263 (19%) ATTRv, 402 (29%) ATTRwt, and 384 (28%) no amyloidosis. Based on comprehensive clinicobiological phenotyping, unsupervised clustering analyses were performed by artificial neural network-based self-organizing maps to identify patient profiles (clusters) with similar characteristics, independent of the final diagnosis and prognosis.

RESULTS

Mean age and left ventricular ejection fraction were 72 ± 13 years and 52% ± 13%, respectively. The authors identified 7 clusters of patients with contrasting profiles and prognosis. AL patients were distinctively located within a typical cluster; ATTRv patients were distributed across 4 clusters with varying clinical presentations, 1 of which overlapped with patients without amyloidosis; interestingly, ATTRwt patients spread across 3 distinct clusters with contrasting risk factors, biological profiles, and prognosis.

CONCLUSIONS

Clustering analysis identified 7 clinical profiles with varying characteristics, prognosis, and associations with diagnosis. Especially in patients with ATTRwt, these results suggest key areas to improve amyloidosis diagnosis and stratify prognosis depending on associated risk factors.

Serial scanning with 99mTc-3, 3-diphosphono-1, 2-propanodicarboxylic acid (99mTc-DPD) for early detection of cardiac amyloid deposition and prediction of clinical worsening in subjects carrying a transthyretin gene mutation

BACKGROUND

To determine the capability of 99mTc-DPD scintigraphy to detect early cardiac involvement and predict clinical worsening in transthyretin (TTR) gene mutation patients.

METHODS

Eleven mutated subjects with normal interventricular septum (IVS) thickness, NT-proBNP level and no cardiac symptoms underwent three seriate 99mTc-DPD scans (visually and semiquantitatively analyzed), and was followed-up for 5-8-years.

RESULTS

Six patients showed no myocardial accumulation in all scans. Increased IVS thickness occurring in one patient 4 years after the last scan was the only abnormal finding in these patients; no cardiac symptoms developed during the follow-up. In three patients, cardiac radiotracer uptake was found at enrollment; other laboratory/instrumental abnormal findings occurred later and cardiac symptoms developed during the follow-up period. Two patients had a negative 99mTc-DPD scan at enrollment and showed cardiac uptake in the following scans. Increased mean left-ventricular (LV) wall thickness was found 3 years after positive scintigraphy; NT-proBNP increased later in one patient. These patients developed cardiac symptoms during the follow-up period.

CONCLUSIONS

99mTc-DPD scan detects cardiac involvement in subjects with TTR gene mutation earlier than ECG, echocardiography and biochemical markers, occurring some years before the fulfillment of current diagnostic criteria for cardiac amyloidosis. A positive 99mTc-DPD scan predicts cardiac symptoms onset.

Imaging Techniques as an Aid in the Early Detection of Cardiac Amyloidosis

The idea that performing a proper succession of imaging tests and techniques allows an accurate and early diagnosis of cardiac amyloidosis, avoiding the need to perform the myocardial biopsy, is becoming increasingly popular. Furthermore, being imaging techniques non-invasive, it is possible to perform the follow-up of the pathology through repeated image acquisitions. In the present review, the various innovative imaging methodologies are presented, and it is discussed how they have been applied for early diagnosis of cardiac amyloidosis (CA), also to distinguish the two most frequent subtypes in CA: immunoglobulin light chain amyloidosis (AL) and transthyretin amyloidosis (ATTR); this allows to perform the therapy in a targeted and rapid manner.

Dealing With High-Risk AL Amyloidosis Patients: A Single Hematologic Center Experience

PURPOSE

To assess the feasibility and the results of Bortezomib-based treatment of "high-risk" AL-amyloidosis patients in a hematology ward.

METHODS

We report on 52 high-risk amyloidosis patients treated with first-line bortezomib-based chemotherapy.

RESULTS

At day 30 from the beginning of the therapy, 23 patients (44%) achieved a hematological response (complete response plus very good partial response); 14 patients (27%) achieved a partial response; 15 patients (29%) were non-responders. After a median follow-up of 28.5 months, the survival rates were 18/23 (78%) for responders; 9/14 (64%) for partial responders and 3/15 (20%) for nonresponders with a median overall survival of 43, 24 and 11 months, respectively (log-rank test: P < .001). NHYA class I-II, NTproBNP < 6500 ng/L, the hematologic response, and the partial hematological response at day 30 independently predicted the survival. There has been no significant difference (P = .173) in survival between revised Mayo stage III and IV patients although there was a trend toward a better prognosis for Mayo stage III. A suboptimal hematological response at day 30 allowed a later organ response in 12/14 patients (85%) even without therapy change and no modification of the hematological status.

CONCLUSIONS

These results show that high-risk AL-amyloidosis patients can be managed safely and effectively in a hematology ward. A partial hematologic response may herald a later better response, organ response, and can allow a subsequent second-line therapy and a good survival.

Diagnosis of wild-type transthyretin amyloid cardiomyopathy in Japan: red-flag symptom clusters and diagnostic algorithm

Wild‐type transthyretin amyloid cardiomyopathy (ATTRwt‐CM) is caused by the deposition of wild‐type transthyretin (TTR) amyloid fibrils in the heart. The age at diagnosis of ATTRwt‐CM is reported to be approximately 70–80 years, and patients commonly present with non‐disease‐specific cardiac abnormalities, such as heart failure with preserved ejection fraction and diastolic dysfunction. The disease can be fatal if left untreated, with an approximate survival of 3–5 years from diagnosis. An oral TTR stabilizer, tafamidis, has enabled early intervention for the treatment of ATTRwt‐CM. However, awareness of ATTRwt‐CM remains low, and misdiagnosis and a delay in diagnosis are common. This review discusses the epidemiology, characteristics, treatment strategy, and red‐flag symptoms and signs of ATTRwt‐CM based on the published literature, as well as recent advances in diagnostic modalities that enable early and accurate diagnosis of the disease. We also discuss an algorithm for early and accurate diagnosis of ATTRwt‐CM in daily clinical practice. In our diagnostic algorithm, a suspected diagnosis of ATTRwt‐CM should be triggered by unexplained left ventricular hypertrophy (LVH), which is LVH that cannot be explained by an increased afterload due to hypertension or valvular disease. In addition, heart failure symptoms, laboratory test results (N‐terminal pro‐B‐type natriuretic peptide, high‐sensitivity troponin T, or high‐sensitivity troponin I), electrocardiogram and imaging (echocardiogram or cardiac magnetic resonance) data, age (≥60 years), and medical history suggestive of ATTRwt‐CM (e.g. carpal tunnel syndrome) should be examined. Detailed examinations using bone scintigraphy and monoclonal protein detection tests followed by tissue biopsy, amyloid typing, and TTR genetic testing are warranted for a definite diagnosis of ATTRwt‐CM.

Ensemble machine learning approach for screening of coronary heart disease based on echocardiography and risk factors

BACKGROUND

Extensive clinical evidence suggests that a preventive screening of coronary heart disease (CHD) at an earlier stage can greatly reduce the mortality rate. We use 64 two-dimensional speckle tracking echocardiography (2D-STE) features and seven clinical features to predict whether one has CHD.

METHODS

We develop a machine learning approach that integrates a number of popular classification methods together by model stacking, and generalize the traditional stacking method to a two-step stacking method to improve the diagnostic performance.

RESULTS

By borrowing strengths from multiple classification models through the proposed method, we improve the CHD classification accuracy from around 70-87.7% on the testing set. The sensitivity of the proposed method is 0.903 and the specificity is 0.843, with an AUC of 0.904, which is significantly higher than those of the individual classification models.

CONCLUSION

Our work lays a foundation for the deployment of speckle tracking echocardiography-based screening tools for coronary heart disease.

Cardiac Transthyretin Amyloidosis: A Nuclear Medicine Leading Role. Situation in a Spanish Center and "State of the Art" in Nuclear Medicine

PURPOSE

Amyloidosis is a heterogeneous group of diseases caused by abnormal extracellular deposition of insoluble proteins and can involve myocardium. One of the causes of myocardial involvement is TTR amyloidosis. Our objective has been to evaluate the situation of cardiac amyloidosis (CA) in our center and the role of nuclear medicine, and to review the state of the art of nuclear medicine in this entity.

PATIENTS AND METHODS

We have evaluated retrospectively 186 patients with clinical suspicion of CA and analyzed the clinical characteristics, free light chains and immunofixation in serum and/or urine, and the most relevant biomarkers associated with transthyretin CA (C-ATTR) of these patients and compared them with the results of the 99mTc-DPD scintigraphy.

RESULTS

We have verified the growing bibliographic evidence concerning C-ATTR. A total of 51 scintigraphies (27.4%) were positive, 2 (1.1%) indeterminate and 133 (71.5%) negative according to the Perugini score. ATTR was diagnosed in 22 (11.8%; 77.3% males; mean age, 79.4 years). Of these, 12 (75% men; 82.3 years) were ATTRwt (wild-type or age-associated) patients, 2 (50% men; 52 years) experienced ATTRv (variant or hereditary), and 8 (87.5% men; 82.3 years) were not classified because of the absence genetic test. The origin of amyloidosis could not be determined in 31 (16.7%; 80.7% males; 84.5 years). In 29 of them (93.6%), it was because there was no study of free light chains or immunofixation.

CONCLUSIONS

Nuclear medicine is playing an increasing role in the diagnosis and classification of CA. However, the monitoring of these is still patchy.

Early Impairment of Right Ventricular Morphology and Function in Transthyretin-Related Cardiac Amyloidosis

Background:

Our study aimed to evaluate right ventricular (RV) morphology and strain (S) in the early stage of familial transthyretin (TTR) cardiac amyloidosis (CA).

Methods and Results:

Thirty-seven patients with transthyretin mutation underwent ^99mTc-3,3-diphosphono-1,2 propanodicarboxylic acid (^99mTc-DPD) scans and/or cardiac magnetic resonance (CMR) to identify TTR CA. Each patient underwent echocardiography to quantify RV dimensions, tricuspid annular plane systolic excursion (TAPSE), systolic pulmonary artery pressure (sPAP), longitudinal (L) strain of the RV free wall, left ventricular (LV) septal thickness (ST), ejection fraction, E/E', LV global (G) L, radial (R), and circumferential (C) S. ^99mTc-DPD and CMR revealed the accumulation in 22 of 37 patients (CA group) and no accumulation in 15 patients (no-CA group). Left ventricular (LV) septal thickness (ST) was higher (P < 0.0001) while LV ejection fraction and E/E' were lower (P < 0.05) in the CA group than the no-CA group. LV-global longitudinal strain (LS) was lower (P < 0.0001) in the CA-group than the no CA-group, whereas LV-global circumferential strain and LV-global radial strain were similar. The CA group showed higher values of RV dimensions (P < 0.05) and sPAP (0.02) and a lower (P = 0.002) TAPSE. Globally, RV-LS was lower (P = 0.005) in the CA group than the no-CA group. Basal and mid segments of the RV free wall showed a lower LS in the CA group than the no-CA group (P < 0.01), while apical S was similar between groups.

Conclusions:

RV deformation, particularly in basal and mid segments, is early impaired in CA.

Deep-learning-based cardiac amyloidosis classification from early acquired pet images

The objective of the present work was to evaluate the potential of deep learning tools for characterizing the presence of cardiac amyloidosis from early acquired PET images, i.e. 15 min after [18F]-Florbetaben tracer injection. 47 subjects were included in the study: 13 patients with transthyretin-related amyloidosis cardiac amyloidosis (ATTR-CA), 15 patients with immunoglobulin light-chain amyloidosis (AL-CA), and 19 control-patients (CTRL). [18F]-Florbetaben PET/CT images were acquired in list mode and data was sorted into a sinogram, covering a time interval of 5 min starting 15 min after the injection. The resulting sinogram was reconstructed using OSEM iterative algorithm. A deep convolutional neural network (CAclassNet) was designed and implemented, consisting of five 2D convolutional layers, three fully connected layers and a final classifier returning AL, ATTR and CTRL scores. A total of 1107 2D images (375 from AL-subtype patients, 312 from ATTR-subtype, and 420 from Controls) have been considered in the study and used to train, validate and test the proposed network. CAclassNet cross-validation resulted with train error mean ± sd of 2.001% ± 0.96%, validation error of 4.5% ± 2.26%, and net accuracy of 95.49% ± 2.26%. Network test error resulted in a mean ± sd values of 10.73% ± 0.76%. Sensitivity, specificity, and accuracy evaluated on the test dataset were respectively for AL-CA sub-type: 1, 0.912, 0.936; for ATTR-CA: 0.935, 0.897, 0.972; for control subjects: 0.809, 0.971, 0.909. In conclusion, the proposed CAclassNet model seems very promising as an aid for the clinician in the diagnosis of CA from cardiac [18F]-Florbetaben PET images acquired a few minutes after the injection.

Practical recommendations for the diagnosis and management of transthyretin cardiac amyloidosis

Cardiac amyloidosis (CA) is an infiltrative restrictive cardiomyopathy caused by accumulation in the heart interstitium of amyloid fibrils formed by misfolded proteins. Most common CA types are light chain amyloidosis (AL) caused by monoclonal immunoglobulin light chains and transthyretin amyloidosis (ATTR) caused by either mutated or wild-type transthyretin aggregates. Previously considered a rare disease, CA is increasingly recognized among patients who may be misdiagnosed as undifferentiated heart failure with preserved ejection fraction (HFPEF), paradoxical low-flow/low-gradient aortic stenosis, or otherwise unexplained left ventricular hypertrophy. Progress in diagnosis has been due to the refinement of cardiac echocardiographic techniques (speckle tracking imaging) and magnetic resonance (T1 mapping) and mostly due to the advent of bone scintigraphy that has enabled noninvasive diagnosis of ATTR, limiting the need for endomyocardial biopsy. Importantly, proper management of CA starts from early recognition of suspected cases among high prevalence populations, followed by advanced diagnostic evaluation to confirm diagnosis and typing, preferentially in experienced amyloidosis centers. Differentiating ATTR from other types of amyloidosis, especially AL, is critical. Emerging targeted ATTR therapies offer the potential to improve outcomes of these patients previously treated only palliatively.

Electromechanical dissociation of left atrium in patients with Cardiac Amyloidosis by Magnetic Resonance: Prognostic and clinical correlates

OBJECTIVES

Left atrial (LA) function is an important marker of hemodynamic status in cardiac amyloidosis (CA), and its characterization may provide relevant prognostic information. We sought to assess the prevalence and prognostic impact of LA dysfunction by cardiac magnetic resonance (CMR) in patients with CA.

METHODS

We performed CMR in 80 consecutive patients with CA, including 38 with AL (47%) and 42 with ATTR (53%). LA function was assessed by acquiring short axis cine steady-state free precession (SSFP) covering the entire chamber. The atrial emptying fraction (AEF) was calculated as the ratio between the difference of LA maximal and minimal volume to LA maximal volume, expressed as percentage. Severe atrial dysfunction was defined as AEF ≤ 14%.

RESULTS

Mean AEF was 18% (13-35%). Overall, AEF ≤ 14% was present in 19 patients (24%), including 21% of those in sinus rhythm (SR) with no history of atrial fibrillation (AF). After a median of 3 years (IQR 2-4), 36 patients (44%) died of cardiac causes. Patients with AEF ≤ 14% showed increased cardiac mortality, with an independent OR of 4.2 (95 IC 2.1-8.2, P < 0.0001). Of note, AEF ≤ 14% was the stronger independent predictor of cardiac death. Patients in SR with AEF ≤ 14% had worse outcome than those with AF.

CONCLUSIONS

Severe impairment of LA contractile function was present in three-quarters of patients with CA, and was prevalent irrespective of CA etiology, both in the presence and absence of AF. Severe LA dysfunction was associated with an independent 4-fold increase in risk for cardiac death at three years.

Assessment of cardiac structure and function in kidney failure: understanding echocardiography and magnetic resonance imaging for the nephrologist

Cardiovascular disease is the leading cause of death in patients with kidney failure or on chronic dialysis. Patients on chronic dialysis have a 10- to 50-fold increased risk of sudden cardiac death compared to patients with normal kidney function. Adverse changes in cardiac structure and function may not manifest with clinical symptoms in patients with kidney failure and, therefore, pose a challenge in identifying cardiac dysfunction early. Fortunately, there are multi-modality cardiac imaging techniques available, including echocardiography and cardiac magnetic resonance imaging, that can help our understanding of the pathophysiology of cardiac dysfunction in kidney failure. This review describes the benefits and limitations of these two commonly available cardiac imaging modalities to assess cardiac structure and function, thereby aiding nephrologists in choosing the most appropriate investigative tool based on individual clinical circumstances. For the purposes of this review, cardiac imaging for detection of coronary artery disease has been omitted.

Left and right ventricular myocardial deformation and late gadolinium enhancement: incremental prognostic value in amyloid light-chain amyloidosis

Background

Previous cardiac magnetic resonance (CMR) studies have shown that both late gadolinium enhancement (LGE) and left ventricular (LV) strain have prognostic value in amyloid light-chain (AL) amyloidosis, but the right ventricular (RV) strain has not yet been studied. We aim to determine the incremental prognostic value of LV and RV LGE and strain in AL amyloidosis.

Methods

This prospective study recruited 87 patients (age, 56.9±9.1 years; M/F, 56/31) and 20 healthy subjects (age, 52.7±8.1 years; M/F, 11/9) who underwent CMR. The LV LGE was classified into no, patchy and global groups. The RV LGE was classified into negative and positive groups. Myocardial deformation was measured using a dedicated software. Follow-up was performed for all-cause mortality using Cox proportional hazards regression and Kaplan-Meier curves.

Results

During a median follow-up of 21 months, 34 deaths occurred. Presence of LV LGE [HR 2.44, 95% confidence interval (CI), 1.10-5.45, P=0.029] and global longitudinal strain (GLS) (HR 1.13 per 1% absolute decrease, 95% CI, 1.02-1.25, P=0.025) were independent LV predictors. RV LGE (HR 4.07, 95% CI, 1.09-15.24, P=0.037) and GLS (HR 1.10 per 1% absolute decrease, 95% CI, 1.00-1.21, P=0.047) were independent RV predictors. Complementary to LV LGE, LV GLS impairment or RV LGE further reduced survival (both log rank P<0.001).

Conclusions

This study confirms the incremental prognostic value of LV GLS and RV LGE in AL amyloidosis, which refines the conventional risk evaluation based on LV LGE. GLS based on non-contrast-enhanced CMR are promising new predictors.

Cardiovascular magnetic resonance imaging for structural heart disease

Cardiovascular magnetic resonance (CMR) has increasingly become a powerful imaging technique over the past few decades due to increasing knowledge about clinical applications, operator experience and technological advances, including the introduction of high field strength magnets, leading to improved signal-to-noise ratio. Its success is attributed to the free choice of imaging planes, the wide variety of imaging techniques, and the lack of harmful radiation. Developments in CMR have led to the accurate evaluation of cardiac structure, function and tissues characterisation, so this non-invasive technique has become a powerful tool for a broad range of cardiac pathologies. This review will provide an introduction of magnetic resonance imaging (MRI) physics, an overview of the current techniques and clinical application of CMR in structural heart disease, and illustrated examples of its use in clinical practice.

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.

Effects of Patisiran, an RNA Interference Therapeutic, on Cardiac Parameters in Patients With Hereditary Transthyretin-Mediated Amyloidosis

BACKGROUND

Hereditary transthyretin-mediated (hATTR) amyloidosis is a rapidly progressive, multisystem disease that presents with cardiomyopathy or polyneuropathy. The APOLLO study assessed the efficacy and tolerability of patisiran in patients with hATTR amyloidosis. The effects of patisiran on cardiac structure and function in a prespecified subpopulation of patients with evidence of cardiac amyloid involvement at baseline were assessed.

METHODS

APOLLO was an international, randomized, double-blind, placebo-controlled phase 3 trial in patients with hATTR amyloidosis. Patients were randomized 2:1 to receive 0.3 mg/kg patisiran or placebo via intravenous infusion once every 3 weeks for 18 months. The prespecified cardiac subpopulation comprised patients with a baseline left ventricular wall thickness ≥13 mm and no history of hypertension or aortic valve disease. Prespecified exploratory cardiac end points included mean left ventricular wall thickness, global longitudinal strain, and N-terminal prohormone of brain natriuretic peptide. Cardiac parameters in the overall APOLLO patient population were also evaluated. A composite end point of cardiac hospitalizations and all-cause mortality was assessed in a post hoc analysis.

RESULTS

In the cardiac subpopulation (n=126; 56% of total population), patisiran reduced mean left ventricular wall thickness (least-squares mean difference ± SEM: -0.9±0.4 mm, P=0.017), interventricular septal wall thickness, posterior wall thickness, and relative wall thickness at month 18 compared with placebo. Patisiran also led to increased end-diastolic volume (8.3±3.9 mL, P=0.036), decreased global longitudinal strain (-1.4±0.6%, P=0.015), and increased cardiac output (0.38±0.19 L/min, P=0.044) compared with placebo at month 18. Patisiran lowered N-terminal prohormone of brain natriuretic peptide at 9 and 18 months (at 18 months, ratio of fold-change patisiran/placebo 0.45, P<0.001). A consistent effect on N-terminal prohormone of brain natriuretic peptide at 18 months was observed in the overall APOLLO patient population (n=225). Median follow-up duration was 18.7 months. The exposure-adjusted rates of cardiac hospitalizations and all-cause death were 18.7 and 10.1 per 100 patient-years in the placebo and patisiran groups, respectively (Andersen-Gill hazard ratio, 0.54; 95% CI, 0.28-1.01).

CONCLUSIONS

Patisiran decreased mean left ventricular wall thickness, global longitudinal strain, N-terminal prohormone of brain natriuretic peptide, and adverse cardiac outcomes compared with placebo at month 18, suggesting that patisiran may halt or reverse the progression of the cardiac manifestations of hATTR amyloidosis.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01960348.

Cardiac amyloidosis: An underdiagnosed/underappreciated disease

Cardiac amyloidosis or amyloid cardiomyopathy (ACM), commonly resulting from extracellular deposition of amyloid fibrils consisted of misfolded immunoglobulin light chain (AL) or transthyretin (TTR) protein, is an underestimated cause of heart failure and cardiac arrhythmias. Among the three types of cardiac amyloidosis (wild-type or familial TTR and light-chain), the wild-type (Wt) TTR-related amyloidosis (ATTR) is an increasingly recognized cause of heart failure with preserved ejection fraction (HFpEF), and amyloidosis should be considered in the differential diagnosis of this heart failure group of patients. Recent advances in the diagnosis and drug treatment of ACM have ushered in a new era in early disease detection and better management of these patients. Certain clues in cardiac and extracardiac manifestations of ACM may heighten clinical suspicion and guide further confirmatory testing. Newer noninvasive imaging methods (strain echocardiography, cardiac magnetic resonance and bone scintigraphy) may obviate the need for endomyocardial biopsy in ATTR patients, while newer targeted therapies may alter the adverse prognosis in these patients. Early recognition of ACM is crucial in halting the disease process before irreversible organ damage occurs. Chemotherapy and stem-cell transplantation combined with immunomodulatory therapy may also favorably affect the course and prognosis of light chain ACM. Finally, in select patients with end-stage disease, heart transplantation may render results comparable to non-ACM patients. All these issues are herein reviewed.

Full-Blown Rheumatoid Heart and Vessels Associated with Rheumatoid Arthritis

We report the case of a 54-year-old female patient with a history of rheumatoid arthritis (RA) who presented with dyspnea on exertion. Her pulsation on both arms was weak. Magnetic resonance (MR) angiography revealed Takayasu's arteritis (TA) characterized by multiple stenosis involving innominate, left common carotid, and left subclavian arteries. With regard to cardiac imaging, coronary computed tomography angiography revealed calcified stenosis of the left anterior descending and diagonal branch arteries, with an abdominal aorta narrowed concomitantly. Restrictive diastolic dysfunction with concentric hypertrophic myocardium was observed on echocardiography, and cardiac MR imaging revealed diffuse, subendocardial late gadolinium enhancement compatible with cardiac amyloidosis (CA). Herein, we describe a case of RA with “full-blown” complications of TA, CA, and coronary artery disease.

Echocardiographic Findings in Cardiac Amyloidosis: Inside Two-Dimensional, Doppler, and Strain Imaging

PURPOSE OF REVIEW

The aim is to provide a description of the most important echocardiographic features in systemic amyloidosis.

RECENT FINDINGS

Amyloidosis is a heterogeneous group of multisystem disorders, characterized by an extracellular deposition of amyloid fibrils. Several imaging tests are available for the diagnosis; however, echocardiography is the cornerstone of the non-invasive imaging modality for cardiac amyloidosis. So far, little is known about the diagnosis of cardiac amyloidosis through imaging modalities. We summarized the most important echocardiographic findings in cardiac amyloidosis. Hence, we offered a systematic report of the diagnostic performance of cardiac amyloidosis using echocardiography.

Isolated cardiac amyloidosis. Utility of bone seeking tracers scintigraphy in differentiating the subtype of amyloid: A case report

BACKGROUND

Three types of amyloid are responsible for cardiac amyloidosis. Differentiation of the subtype is critical for the disease progression and the therapeutic decision.

RESULTS

Myocardial scintigraphy using Tc-PYP is able to differentiate the cardiac amyloid subtype with high sensitivity and specificity. The myocardial uptake of PYP is higher in patients with TTR amyloidosis.

CONCLUSION

Non-invasive tests for the detection of cardiac amyloidosis, like myocardial scintigraphy with bone seeking tracers, can play a major role in the diagnosis progression and therapeutic management of patients with cardiac amyloidosis.

Electrocardiogram and Imaging: An Integrated Approach to Arrhythmogenic Cardiomyopathies

Cardiovascular imaging has radically changed the management of patients with arrhythmogenic cardiomyopathies. This article focuses on the role of echocardiography and MRI in the diagnosis of these structural diseases. Cardiomyopathies with hypertrophic pattern (hypertrophic cardiomyopathy, restrictive cardiomyopathies, amyloidosis, Anderson-Fabry disease, and sarcoidosis), cardiomyopathies with dilated pattern, inflammatory cardiac diseases, and right ventricular arrhythmogenic cardiomyopathy are analyzed. Finally, anatomic predictors of arrhythmias and sudden cardiac death are discussed. Each paragraph is attended by clinical cases that are discussed on the electrocardiogram, after integrated with the anatomic, functional, and hemodynamic modifications of cardiovascular imaging.

Ten Years of 2D Longitudinal Strain for Early Myocardial Dysfunction Detection: A Clinical Overview

In recent years, the role of left ventricular ejection fraction (EF) as the gold standard parameter for the evaluation of systolic function has been questioned, and many efforts have been concentrated in the clinical validation of new noninvasive tools for the study of myocardial contractility. Improvement in the accuracy of speckle-tracking echocardiography has resulted in a large amount of research showing the ability of two-dimensional strain to overcome EF limitations in the majority of primary and secondary heart diseases. Currently, global longitudinal strain (GLS) is considered the most accurate and sensitive parameter for the assessment of early left ventricular dysfunction. This review summarizes the advantages that this measurement can provide in several clinical settings. Moreover, the important cautions that should be considered in making the choice to use GLS also are addressed. Finally, a special focus on bull's-eye polar maps for the assessment of regional changes of longitudinal function and the usefulness of these maps in the differential diagnosis of several diseases is provided.

6MWT performance correlates with peripheral neuropathy but not with cardiac involvement in patients with hereditary transthyretin amyloidosis (hATTR)

Hereditary transthyretin amyloidosis (hATTR) is a life-threatening multisystemic disease with sensory-motor peripheral neuropathy, cardiomyopathy and dysautonomia. Although the six-minute walk test (6MWT) is one of the most popular clinical tests to assess functional exercise capacity in cardiopulmonary and neuromuscular diseases, little is known about 6MWT in evaluating hATTR patients. A prospective single-center pilot study was performed in twenty hATTR patients, comparing 6MWT with widely used outcome measures. After 18 months, fourteen patients were re-evaluated. 6MWT performance was highly related with familial amyloidotic polyneuropathy stage and polyneuropathy disability score, and with CMT examination score, neuropathy impairment score-lower limbs and Kumamoto score. There was no correlation with compound autonomic dysfunction test, modified body mass index and numerous indices of heart dysfunction. After 18 months, familial amyloidotic polyneuropathy stage and polyneuropathy disability score systems were not able to reveal any significant change, whereas all other outcome measures significantly worsened. Among the outcome measures monitoring the neuropathic disturbances, neuropathy impairment score-lower limbs showed the highest responsiveness to change (adjusted effect size: 0.79), followed by CMT examination score (0.67), Kumamoto scale (0.65), 6MWT (0.62). 10MWT showed a very small value (0.21). Compound autonomic dysfunction test had a large value (0.91) whereas modified body mass index a small/moderate value (0.49). 6MWT is a simple and sensitive tool to monitor neuropathic involvement but not cardiac dysfunction in hATTR course.

Diastolic dysfunction evaluated by cardiac magnetic resonance: the value of the combined assessment of atrial and ventricular function

OBJECTIVES

We sought to evaluate the role of cardiac magnetic resonance imaging (CMR) in the evaluation of diastolic function by a combined assessment of left ventricular (LV) and left atrial (LA) function in a cohort of subjects with various degrees of diastolic dysfunction (DD) detected by echocardiography.

METHODS

Forty patients with different stages of DD and 18 healthy controls underwent CMR. Short-axis cine steady-state free precession images covering the entire LA and LV were acquired. Parameters of diastolic function were measured by the analysis of the LV and LA volume/time (V/t) curves and the respective derivative dV/dt curves.

RESULTS

At receiver operating characteristic (ROC) curve analysis, the peak of emptying rate A indexed by the LV filling volume with a cut-off of 3.8 was able to detect patients with grade I DD from other groups (area under the curve [AUC] 0.975, 95% confidence interval [CI] 0.86-1). ROC analysis showed that LA ejection fraction with a cut-off of ≤36% was able to distinguish controls and grade I DD patients from those with grade II and grade III DD (AUC 0.996, 95% CI 0.92-1, p < 0.001). The isovolumetric pulmonary vein transit ratio with a cut-off of 2.4 allowed class III DD to be distinguished from other groups (AUC 1.0, 95%CI 0.93-1, p < 0.001).

CONCLUSIONS

Analysis of LV and LA V/t curves by CMR may be useful for the evaluation of DD.

KEY POINTS

• Combined atrial and ventricular volume/time curves allow evaluation of diastolic function. • Atrial emptying fraction allows distinction between impaired relaxation and restrictive/pseudo-normal filling. • Isovolumetric pulmonary vein transit ratio allows distinction between restrictive and pseudo-normal filling.

Myocardial native T2 measurement to differentiate light-chain and transthyretin cardiac amyloidosis and assess prognosis

BACKGROUND

To assess the diagnostic and prognosis value of myocardial native T2 measurement in the distinction between Light-chain (AL) and Transthyretin (ATTR) cardiac amyloidosis (CA).

METHODS

Forty-four patients with CA (24 AL; 20 ATTR) and 40 healthy subjects underwent 1.5 T cardiovascular magnetic resonance (CMR). They all underwent T1 and T2 mapping (modified Look-Locker inversion recovery), cine and late gadolinium enhancement (LGE) imaging. The Query Amyloid Late Enhancement (QALE) score, myocardial native T2, T1 and extra cellular volume fraction (ECV) were calculated for all patients.

RESULTS

Of the 44 patients, 36 (82%) exhibited enhancement on LGE images. Mean QALE score of AL (7.9 ± 6) and ATTR (10.5 ± 5) patients were similar (p = 0.6). Myocardial native T2 was significantly (p < 0.0001) higher in AL (63.2 ± 4.7 ms) than in ATTR (56.2 ± 3.1 ms) patients, and both higher (p < 0.001) than healthy subjects (51.1 ± 3.1 ms). Myocardial native T2 was highly correlated with myocardial native T1 (Spearman's rho = 0.79; p < 0.001) and exhibited higher diagnostic performance than T1 to separate AL and ATTR patients: the area under curve (AUC) of T2 was 0.94 (95% CI: 0.86-1, p < 0.001) and the AUC of T1 was 0.77 (95% CI: 0.62-0.91, p = 0.03). Myocardial native T2 did not impact overall survival in patients (HR 1.03 (0.94-1.12); p = 0.53) in contrast to ECV that was the best predictor of outcome (HR 1.66 per 0.1 increase in ECV (1.24-2.22); p = 0.0006).

CONCLUSIONS

Myocardial native T2 significantly is increased in CA, especially in AL patients in comparison to ATTR patients. Myocardial native T2 does not impact survival in CA patients in contrast to ECV that was the best predictor of outcome.

TRIAL REGISTRATION

Trial Registration and unique number: CNIL cardio 1778041. Date of registration: 20 December 2012.

Unexpected manifestation of cardiac amyloidosis

This report discusses an unusual case of cardiac amyloidosis. We report a patient who presented with unexplained ascites on a background of stable hypertension and mild left ventricular systolic dysfunction, cardiovascular complaints commonly associated with age. Due to the unspecific nature of his cardiovascular symptoms, it took 2 years of recurrent, unresolved ascites, numerous investigations, shifting differential diagnoses and significant cardiovascular deterioration before cardiac amyloidosis was recognised, by which the disease was at end stage. This case emphasises the need for more discriminating clinical features in the diagnosis of cardiac amyloidosis and advocates unexplained, recurrent ascites as a possible candidate.

Multimodality Imaging in Restrictive Cardiomyopathies: An EACVI expert consensus document In collaboration with the "Working Group on myocardial and pericardial diseases" of the European Society of Cardiology Endorsed by The Indian Academy of Echocardiography

Restrictive cardiomyopathies (RCMs) are a diverse group of myocardial diseases with a wide range of aetiologies, including familial, genetic and acquired diseases and ranging from very rare to relatively frequent cardiac disorders. In all these diseases, imaging techniques play a central role. Advanced imaging techniques provide important novel data on the diagnostic and prognostic assessment of RCMs. This EACVI consensus document provides comprehensive information for the appropriateness of all non-invasive imaging techniques for the diagnosis, prognostic evaluation, and management of patients with RCM.

Advanced Non-invasive Imaging Techniques in Chronic Heart Failure and Cardiomyopathies : Focus on Cardiac Magnetic Resonance Imaging and Computed Tomographic

Cardiomyopathies (Cs) are a heterogeneous group of myocardial diseases with structural and/or functional abnormalities.The aetiology is due to genetic-family substrate in most cases, however, the correct and detailed analysis of morphofunctional abnormalities (severity and distribution of hypertrophy, ventricular dilatation, ventricular dysfunction) and tissue characteristics (myocardial fibrosis, myocardial infiltration) are a crucial element for a definite diagnosis.Among the different diagnostic imaging modalities applied in clinical practice (echocardiography, nuclear medicine), cardiac magnetic resonance (CMR) has emerged as a non-invasive diagnostic tool having high ability to quantify systolic function and tissue abnormalities that represent the substrates of many Cs.The main added value of CMR is the ability to identify cardiomyopathies with respect to ischemic heart disease and, above all, to discriminate the major types of cardiomyopathies based on morpho-functional presentation patterns and the presence and location of myocardial fibrosis.Many CMR elements allow increasing diagnostic accuracy but CMR data should be integrated with an appropriate clinical and instrumental context.Computed Tomographic (CT) scan technology has showed a complementary role in patients having Cs and HF.In this chapter, the diagnostic, pathophysiologic and prognostic value of CMR and CT in heart failure due to the most common cardiomyopathies will be discussed.

Recent advances in the noninvasive strategies of cardiac amyloidosis

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

Cardiac amyloidosis is prevalent in older patients with aortic stenosis and carries worse prognosis

BACKGROUND

Non-invasive cardiac imaging allows detection of cardiac amyloidosis (CA) in patients with aortic stenosis (AS). Our objective was to estimate the prevalence of clinically suspected CA in patients with moderate and severe AS referred for cardiovascular magnetic resonance (CMR) in age and gender categories, and assess associations between AS-CA and all-cause mortality.

METHODS

We retrospectively identified consecutive AS patients defined by echocardiography referred for further CMR assessment of valvular, myocardial, and aortic disease. CMR identified CA based on typical late-gadolinium enhancement (LGE) patterns, and ancillary clinical evaluation identified suspected CA. Survival analysis with the Log rank test and Cox regression compared associations between CA and mortality.

RESULTS

There were 113 patients (median age 74 years, Q1-Q3: 62-82 years), 96 (85%) with severe AS. Suspected CA was present in 9 patients (8%) all > 80 years. Among those over the median age of 74 years, the prevalence of CA was 9/57 (16%), and excluding women, the prevalence was 8/25 (32%). Low-flow, low-gradient physiology was very common in CA (7/9 patients or 78%). Over a median follow-up of 18 months, 40 deaths (35%) occurred. Mortality in AS + CA patients was higher than AS alone (56% vs. 20% at 1-year, log rank 15.0, P < 0.0001). Adjusting for aortic valve replacement modeled as a time-dependent covariate, Society of Thoracic Surgery predicted risk of mortality, left ventricular ejection fraction, CA remained associated with all-cause mortality (HR = 2.92, 95% CI = 1.09-7.86, P = 0.03).

CONCLUSIONS

Suspected CA appears prevalent among older male patients with AS, especially with low flow, low gradient AS, and associates with all-cause mortality. The importance of screening for CA in older AS patients and optimal treatment strategies in those with CA warrant further investigation, especially in the era of transcatheter aortic valve implantation.

Increased Prognostic Value of Query Amyloid Late Enhancement Score in Light-Chain Cardiac Amyloidosis

BACKGROUND

Late gadolinium enhancement (LGE) pattern is a powerful imaging biomarker for prognosis of cardiac amyloidosis. It is unknown if the query amyloid late enhancement (QALE) score in light-chain (AL) amyloidosis could provide increased prognostic value compared with LGE pattern.Methods and Results:Seventy-eight consecutive patients with AL amyloidosis underwent contrast-enhanced cardiovascular magnetic resonance imaging. Patients with cardiac involvement were grouped by LGE pattern and analyzed using QALE score. Receiver operating characteristic curve was used to identify the optimal cut-off for QALE score in predicting all-cause mortality. Survival of these patients was analyzed with the Kaplan-Meier method and multivariate Cox regression. During a median follow-up of 34 months, 53 of 78 patients died. The optimal cut-off for QALE score to predict mortality at 12-month follow-up was 9.0. On multivariate Cox analysis, QALE score ≥9 (HR, 5.997; 95% CI: 2.665-13.497; P<0.001) and log N-terminal pro-brain natriuretic peptide (HR, 1.525; 95% CI: 1.112-2.092; P=0.009) were the only 2 independent predictors of all-cause mortality. On Kaplan-Meier analysis, patients with subendocardial LGE can be further risk stratified using QALE score ≥9.

CONCLUSIONS

The QALE scoring system provides powerful independent prognostic value in AL cardiac amyloidosis. QALE score ≥9 has added value to differentiate prognosis in AL amyloidosis patients with a subendocardial LGE pattern.

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.

Case 244: Systemic Amyloidosis-A Complication of Waldenström Macroglobulinemia

History A 68-year-old man was admitted to the hospital for work-up because of generalized fatigue, anorexia, chronic diarrhea, and weight loss. Laboratory work-up revealed an erythrocyte sedimentation rate of 58 mm/h (reference range, 3-23 mm/h), a hemoglobin level of 14.1 g/dL (reference range, 13.8-17.5 g/dL), a leukocyte count of 8.1 × 10⁹/L (reference range, [3.4-9.7] × 10⁹/L), a platelet count of 223 × 10⁹/L (reference range, [158-424] × 10⁹/L), an alkaline phosphatase level of 85 U/L (1.42 μkat/L) (normal level, <142 U/L [2.37 μkat/L]), a serum creatinine level of 93 μmol/L (reference range, 79-125 μmol/L), a serum total protein level of 82 g/L (reference range, 66-81 g/L), a serum albumin level of 39.3 g/L (reference range, 40.2-47.6 g/L), an albumin-to-globulin ratio (a test showing relative amounts of major plasma proteins) of 0.92 (reference range, 0.8-2.0), a urine protein level of 15 mg/dL (normal level, <20 mg/dL), a total serum calcium level of 2.46 mmol/L (reference range, 2.14-2.53 mmol/L), and a carcinoembryonic antigen value of 2.69 μg/L (normal value, <3.4 μg/L). Serology findings were negative for celiac disease. Thyroid function was normal, as were 5-hydroxyindoleacetic acid and chromogranin A levels. Initial radiologic examination included chest radiography and plain abdominal erect radiography. Gastrointestinal endoscopy was performed to rule out inflammatory bowel disease or gastrointestinal neoplasm as a cause of chronic diarrhea. Endoscopic mucosal resection of two polyps from the cardia and duodenal bulb was performed during esophagogastroduodenoscopy, but histologic findings at hematoxylin-eosin staining were normal. Colonoscopy revealed diverticulosis involving the entire colon. Serum immunoelectrophoresis showed a monoclonal band, which was confirmed to be immunoglobulin Mλ at immunofixation. After histologic analysis of the bone marrow biopsy specimen, diagnosis of Waldenström macroglobulinemia was established, and computed tomography (CT) of the thorax, abdomen, and pelvis was requested to depict lymphadenopathy and organomegaly. On the basis of CT findings, two more specimens considered highly sensitive for the CT diagnosis were obtained via minimally invasive biopsy, but the results were negative. Magnetic resonance (MR) imaging was performed a year later to control the progression of CT findings.

Diagnostic score for the detection of cardiac amyloidosis in patients with left ventricular hypertrophy and impact on prognosis

BACKGROUND

Among diagnosis associated with left ventricular hypertrophy (LVH), cardiac amyloidosis (CA) is a progressive disease with poor prognosis. Early noninvasive identification is of growing clinical importance. The objective of our study was to integrate clinical, biologic, electrocardiographic and echocardiographic parameters to build a diagnostic score in patients with LVH.

METHODS AND RESULTS

One hundred and fourteen patients with LVH underwent a cardiac magnetic resonance (CMR) and a ^99mTc-hydroxymethylene-diphosphonate scintigraphy (^99mTc-HMDP) allowing to discriminate three groups of diagnoses: CA (n = 50 including 31, 18 and 1 ATTR, AL and AA amyloidosis), hypertrophic cardiomyopathy (n = 19) and unspecific cardiomyopathy (n = 45). Seven continuous variables associated with CA (systolic arterial pressure <130 mmHg; PR duration >200 ms; Sokolow index <12 mV; diastolic left ventricular posterior thickness >13 mm; E/Ea ratio >10; global longitudinal strain > -12% and sum of basal longitudinal strain > -47%) were selected and dichotomized according to the best cutoff value to build the diagnostic score, which was validated in an independent cohort of 34 patients with LVH from aortic stenosis. The area under the ROC curve for the diagnosis of CA using the score was 0.933 (95%CI 0.889-0.978). The best cut off value for the score was 3 leading to a sensitivity of 90% and specificity of 81%. Area under the ROC curve for the score was 0.932 in the validation cohort. A diagnostic score >3 was associated with a poorest prognosis.

CONCLUSION

An integrated evaluation of 6 diagnostic factors including arterial blood pressure, ECG and echocardiographic parameters to build a diagnostic score is a simple and easily method to discriminate the 3 main CA in patients with LVH.

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.