Myocardial extracellular volume quantification using CT for the identification of occult cardiac amyloidosis in patients with severe aortic stenosis referred for transcatheter aortic valve replacement

Multimodality imaging in cardiac amyloidosis: State-of-the-art review

Amyloidosis is a systemic disease, characterized by deposition of amyloid fibrils in various organs, including the heart. For the diagnosis of cardiac amyloidosis (CA) it is required a high level of clinical suspicion and in the presence of clinical, laboratorial, and electrocardiographic red flags, a comprehensive multimodality imaging evaluation is warranted, including echocardiography, magnetic resonance, scintigraphy, and computed tomography, that will confirm diagnosis and define the CA subtype, which is of the utmost importance to plan a treatment strategy. We will review the use of multimodality imaging in the evaluation of CA, including the latest applications, and a practical flow-chart will sum-up this evidence.

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.

Sex-related differences in the clinical characteristics of wild-type transthyretin amyloidosis cardiomyopathy

BACKGROUND

A significant male predominance has been reported in wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM). Hence, female cases of ATTRwt-CM are overlooked, and sex-related differences in ATTRwt-CM remain unclear. This study aimed to examine sex-related differences in clinical characteristics and diagnostic approaches in ATTRwt-CM.

METHODS

We retrospectively analyzed 199 consecutive patients who were diagnosed with ATTRwt-CM and evaluated sex-related differences in clinical characteristics, imaging parameters, biomarkers, and diagnostic approaches.

RESULTS

Twenty-nine patients (15%) were female. These female patients were significantly older at diagnosis (77.1 ± 6.5 years vs. 82.9 ± 4.8 years; p<0.001) and had a more advanced New York Health Association functional class (2.2 ± 0.7 vs. 2.6 ± 0.8; p = 0.006) than their male counterparts. The median B-type natriuretic peptide levels were significantly higher (236 pg/mL vs. 394 pg/mL; p = 0.017) in female patients. Echocardiography revealed that the mean interventricular septum diameter was thinner (15.7 ± 2.6 mm vs. 14.1 ± 2.5 mm; p = 0.004) and left ventricular ejection fraction (LVEF) was preserved (51.2 ± 10.2% vs. 57.2 ± 9.1%; p = 0.003) in female patients. The mean heart-to-contralateral ratio obtained using ^99mTc-labeled pyrophosphate (^99mTc-PYP) was significantly lower (1.89 ± 0.33 vs. 1.63 ± 0.20; p < 0.001), moderate to severe aortic stenosis was more frequently observed (5% vs. 45%; p < 0.001), and the frequency of histological diagnosis was significantly lower (77% vs. 59%; p = 0.036) in female patients.

CONCLUSIONS

Female patients with ATTRwt-CM were predominantly octogenarians and less hypertrophic and had preserved LVEF and weaker cardiac uptake of the ^99mTc-PYP tracer compared with male patients. These characteristics contribute to the underdiagnosis of ATTRwt-CM in female patients.

Transthyretin amyloidosis in aortic stenosis: clinical and therapeutic implications

About one in seven elderly patients with severe calcific aortic stenosis (AS) also have ATTR amyloid cardiomyopathy (AC-TTR). The reasons for this close association are not fully known, but the two entities are not only related by common epidemiology. For example, it is possible to hypothesize that an amyloidotic infiltration of the aortic valve, even partial, can act as a trigger for the development of endothelial damage and subsequent calcification. Another hypothesis is the increased myocardial strain induced by AS may locally favour the process of amyloidogenesis and tissue infiltration. In a patient with AS, the coexistence of AC-TTR can be suspected by careful analysis of the echocardiogram and the ECG, especially if a clinical history of carpal tunnel syndrome coexists. Bone tracer scintigraphy allows a diagnosis of certainty. Recently, several studies have evaluated the prognostic implications of the coexistence of the two entities in candidates for percutaneous aortic valve replacement, showing how amyloidosis would not significantly impact the results of the procedure, but would only be associated with a greater risk of distant heart failure. In patients with AS associated with AC-TTR, valve replacement should not be ruled out in the presence of the usual clinical-haemodynamic indications.

The Importance of Multimodality Imaging in the Diagnosis and Management of Patients with Infiltrative Cardiomyopathies: An Update

Infiltrative cardiomyopathies (ICMs) comprise a broad spectrum of inherited and acquired conditions (mainly amyloidosis, sarcoidosis, and hemochromatosis), where the progressive buildup of abnormal substances within the myocardium results in left ventricular hypertrophy and manifests as restrictive physiology. Noninvasive multimodality imaging has gradually eliminated endomyocardial biopsy from the diagnostic workup of infiltrative cardiac deposition diseases. However, even with modern imaging techniques’ widespread availability, these pathologies persist in being largely under- or misdiagnosed. Considering the advent of novel, revolutionary pharmacotherapies for cardiac amyloidosis, the archetypal example of ICM, a standardized diagnostic approach is warranted. Therefore, this review aims to emphasize the importance of contemporary cardiac imaging in identifying specific ICM and improving outcomes via the prompt initiation of a targeted treatment.

Clinical characteristics and natural history of wild-type transthyretin amyloid cardiomyopathy in Japan

Aims

The focus on wild‐type transthyretin amyloid cardiomyopathy (ATTRwt‐CM) is increasing because of novel treatment options. There is currently no report on a large number of Japanese patients with ATTRwt‐CM. The study aimed to examine the characteristics and prognosis of ATTRwt‐CM in Japan.

Methods and results

Consecutive patients (78.5 ± 6.4 years old at diagnosis) with ATTRwt‐CM diagnosed at Kumamoto University Hospital between December 2002 and December 2019 were retrospectively reviewed. Data, including demographic characteristics, co‐morbidities, clinical manifestations at diagnosis, laboratory results, electrocardiographic and echocardiographic data, imaging and pathological findings, and treatment were obtained. Of 129 patients included in this study, 110 patients (85%) were male. The median period from initial symptom onset to diagnosis was 15.5 (2–75) months. Heart failure was the most common clinical manifestation leading to diagnosis (61%) and initial manifestations (49%). Of 106 patients, carpal tunnel syndrome was observed in 57 patients (54%), and the median period from initial symptom onset to diagnosis was 96 (48–120) months. Histopathological confirmation of transthyretin amyloid was achieved in 94 patients (73%), including 66 (51%) and 28 cases (22%) with endomyocardial and extracardiac biopsies. During the observation period (median 15.0 [inter‐quartile range, 5.4–33.2] months after diagnosis), 34 patients (26%) died. Of these, 27 patients (79%) had cardiovascular deaths (heart failure, 25; sudden death, two). The median survival duration was 58.9 months and the 5 years' survival rate was 48%. According to a multivariate Cox hazard analysis, age [hazard ratio (HR), 1.14; 95% confidence interval (CI), 1.05–1.23, P = 0.002] and low serum sodium levels (HR, 0.89; 95% CI, 0.79–0.996; P = 0.04) contributed to all‐cause mortality, and low serum sodium levels contributed to hospitalization for heart failure (HR, 0.86; 95% CI, 0.77–0.96; P = 0.005).

Conclusions

Clinical characteristics and prognosis of ATTRwt‐CM patients in Japan were examined. Carpal tunnel syndrome can be considered an indication for diagnosis of ATTRwt‐CM. Age and low serum sodium level were significant predictive factors of all survival outcomes. The clinical features of ATTRwt‐CM should be recognized to provide appropriate treatment.