The Role of Multi-modality Imaging in the Diagnosis of Cardiac Amyloidosis: A Focused Update

Clinical suspicion, diagnosis and management of cardiac amyloidosis: update document and executive summary

In recent years, the interest in cardiac amyloidosis has grown exponentially. However, there is a need to improve our understanding of amyloidosis in order to optimise early detection systems. Therefore, it is crucial to incorporate solutions to improve the suspicion, diagnosis and follow-up of cardiac amyloidosis. In this sense, we designed a tool following the different phases to reach the diagnosis of cardiac amyloidosis, as well as an optimal follow-up: a) clinical suspicion, where the importance of the "red flags" to suspect it and activate the diagnostic process is highlighted; 2) diagnosis, where the diagnostic algorithm is mainly outlined; and 3) follow-up of confirmed patients. This is a practical resource that will be of great use to all professionals caring for patients with suspected or confirmed cardiac amyloidosis, to improve its early detection, as well as to optimise its accurate diagnosis and optimal follow-up.

Early diagnostic and prognostic value of myocardial strain derived from cardiovascular magnetic resonance in patients with cardiac amyloidosis

Background

Cardiac amyloidosis (CA) is one of the causes of heart failure with preserved ejection fraction. Cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) and extracellular volume (ECV) fractions is a preferred method to identify CA. However, the requirement of contrast limits its use in renal deficiency patients. Myocardial strain is a promising method without contrast. We sought to assess the early diagnostic and prognostic value of strain.

Methods

This retrospective study enrolled 31 patients with systemic amyloidosis (SA) in Peking University First Hospital from January 2014 to January 2019. The patients were categorized into three groups, including 11 CA patients with left ventricular hypertrophy (CA-LVH group), 9 CA patients without LVH (CA-NLVH group), and 11 patients with extracardiac SA (SA group). Strain analysis was performed with CMR images. A least absolute shrinkage and selection operator (LASSO) was used to generate strain score. The receiver operating characteristic (ROC) curve was used to evaluate the early diagnostic efficacy of strain score and other single strain parameter. The primary endpoint was defined as death from all cause or rehospitalization for heart failure. A Cox proportional hazards model was used to assess the index value on the prognosis.

Results

In CA patients, as the left ventricular wall thickens, the global and regional strain decrease significantly. A new strain score (strain score = 0.00893 × mid-septal circumferential peak strain + 0.02285 × apical radial peak strain + 0.1541 × apical circumferential peak strain + 0.33097 × epicardial circumferential average peak strain + 0.42232 × endocardial longitudinal average peak strain) generated using LASSO showed that the area under the ROC curve was 0.909. All the patients with outcome events were in CA groups, four were in CA-LVH group and one in CA-NLVH group. New York Heart Association (NYHA) grade [hazard ratio (HR) =14.29, 95% confidence interval (CI): 2.34-87.34, P<0.01], brain natriuretic peptide (HR =20.05, 95% CI: 2.21-182.36, P=0.008), cardiac injury biomarker (HR =11.59, 95% CI: 1.03-130.36, P=0.047), E/E' (mitral inflow to mitral relaxation velocity ratio) (HR =1.09, 95% CI: 1.00-1.18, P=0.040), end-systolic left ventricular volume (HR =1.04, 95% CI: 1.00-1.18, P=0.039) and LGE volume (HR =1.11, 95% CI: 1.02-1.20, P=0.012) positively correlate with events. Better renal function (HR =0.92, 95% CI: 0.86-0.98, P=0.011) and ejection fraction (HR =0.94, 95% CI: 0.88-0.99, P=0.027) appear to be protective factors. Although with no statistical difference, the strain damage had a tendency to predict poor prognosis, i.e., mid-ventricular circumferential strain with HR of 1.25 (95% CI: 1.0-1.57, P=0.050) and strain score with HR of 1.30 (95% CI: 0.98-1.73, P=0.067).

Conclusions

Myocardial strain decreased in CA patients. The integrated magnetic resonance imaging (MRI) strain score can serve as a useful tool to identify early myocardial involvement in amyloidosis. The strain damage had a tendency to predict poor prognosis.

Multimodality imaging in the diagnostic management of concomitant aortic stenosis and transthyretin-related wild-type cardiac amyloidosis

Severe aortic stenosis (AS) is the most common valvular heart disease with a prevalence rate of more than 4% in 75-year-old people or older. Similarly, cardiac amyloidosis (CA), especially "wild-type transthyretin" (wTTR), has shown a prevalence rate ranging from 22% to 25% in people older than 80 years. The detection of the concomitant presence of CA and AS is challenging primarily because of the similar type of changes in the left ventricle caused by AS and CA, which share some morphological characteristics. The aim of this review is to identify the imaging triggers in order to recognize occult wtATTR-CA in patients with AS, clarifying the crucial step of the diagnostic process. Multimodality imaging methods such as echocardiography, cardiac magnetic resonance, cardiac computed tomography, and DPD scintigraphy will be analyzed as part of the available diagnostic workup to identify wtATTR-CA early in patients with AS.

Assessment of left ventricle myocardial deformation in a hemorrhagic shock swine model by two-dimensional speckle tracking echocardiography

BACKGROUND

Trauma-induced secondary cardiac injury has been associated with significant adverse cardiovascular events. Speckle tracking echocardiography is a novel technology that allows an accurate and reproducible cardiac structure and function assessment. We evaluated the left ventricle (LV) myocardial deformation by speckle tracking echocardiography in a hemorrhagic shock (HS) swine model.

METHODS

Seven healthy male Landrace pigs were included in this study. Severe HS was reached through three sequentially blood withdraws of 20% of estimated blood volume, and it was maintained for 60 minutes. Volume resuscitation was performed using all precollected blood volume. A 1.8- to 4.2-MHz phased-array transducer was used to acquire the two-dimensional echocardiography images. Strain measurements were obtained semiautomatically by wall motion tracking software. Results are presented as medians and interquartile ranges and compared using Wilcoxon rank-sum test. A p value of <0.05 was considered statistically significant.

RESULTS

The median weight was 32 (26.1-33) kg, and the median total blood volume withdrawn was 1,100 (1,080-1,190) mL. During the severe HS period, the median arterial systemic pressure was 39 (36-46) mm Hg, and the cardiac index was 1.7 (1.6-2.0) L/min/m 2 . There was statistically significant absolute decrease in the global longitudinal strain 2 hours postresuscitation comparing with the basal measurements (-9.6% [-10.7 to -8.0%] vs. -7.9% [-8.1 to -7.4%], p = 0.03). There were no statistically significant differences between the basal and 2 hours postresuscitation assessments in the invasive/noninvasive hemodynamic, other two-dimensional echocardiogram (LV ejection fraction, 49.2% [44-54.3%] vs. 53.2% [51.5-55%]; p = 0.09), and circumferential strain (-10.6% [-14.4 to -9.0%] vs. -8.5% [-8.6 to -5.2%], p = 0.06) parameters.

CONCLUSION

In this experimental swine model of controlled HS, LV global longitudinal strain analysis accurately characterizes the timing and magnitude of subclinical cardiac dysfunction associated with trauma-induced secondary cardiac injury.

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.

Multimodality Cardiac Imaging in Cardiomyopathies: From Diagnosis to Prognosis

Cardiomyopathies are a group of structural and/or functional myocardial disorders which encompasses hypertrophic, dilated, arrhythmogenic, restrictive, and other cardiomyopathies. Multimodality cardiac imaging techniques are the cornerstone of cardiomyopathy diagnosis; transthoracic echocardiography should be the first-line imaging modality due to its availability, and diagnosis should be confirmed by cardiovascular magnetic resonance, which will provide more accurate morphologic and functional information, as well as extensive tissue characterization. Multimodality cardiac imaging techniques are also essential in assessing the prognosis of patients with cardiomyopathies; left ventricular ejection fraction and late gadolinium enhancement are two of the main variables used for risk stratification, and they are incorporated into clinical practice guidelines. Finally, periodic testing with cardiac imaging techniques should also be performed due to the evolving and progressive natural history of most cardiomyopathies.