Novel insights in cardiac imaging to evaluate disease progression and mechanisms in cardiac amyloidosis

Introduction: Systemic amyloidosis is characterised by the extracellular deposition of amyloid fibrils that misfold and aggregate causing disease when accumulation is sufficient to disrupt the structure and integrity of affected organs. Cardiac involvement causes a restrictive cardiomyopathy and determines prognosis. / Aims: My aims were 1) To assess the echocardiographic phenotype of patients with transthyretin (ATTR) cardiomyopathy and evaluate determinants of prognosis at baseline 2) To describe the echocardiographic progression in patients with ATTR cardiomyopathy over serial assessment 3) To assess the role of cardiac magnetic resonance (CMR)-derived extracellular volume (ECV) mapping to detect and estimate extra-cardiac amyloid load against Serum Amyloid P (SAP) scintigraphy 4) To assess the presence and mechanisms of myocardial ischaemia using stress perfusion CMR. / Results and Conclusions: Results demonstrate that 1) At baseline echocardiographic assessment in ATTR cardiomyopathy, stroke volume index, right atrial area index, longitudinal strain, E/e’ and severe aortic stenosis were independently associated with mortality. Compared to other genotypes, patients with V122I-associated ATTR cardiomyopathy had the most severe degree of dysfunction. 2) Worsening in the degree of mitral and tricuspid regurgitation at 12 and-24 months was associated with worse prognosis by echocardiography, and patients with V122-associated ATTR cardiomyopathy had more rapid progression when compared to other genotypes. 3) CMR derived ECV mapping shows high diagnostic performance to detect splenic and hepatic amyloid deposits with good correlation between ECV and amyloid load assessed by SAP scintigraphy. 4) Myocardial blood flow assessed by stress perfusion CMR is severely reduced in patients with cardiac amyloidosis and histological analysis of endomyocardial tissue shows evidence of hypoxia, vascular infiltration and capillary rarefaction. In conclusion, these results demonstrate that imaging in cardiac amyloidosis has an important role in optimising diagnosis, tracking individual changes over time and characterising amyloid organ involvement

Multi-Imaging Characterization of Cardiac Phenotype in Different Types of Amyloidosis

BACKGROUND: Bone scintigraphy is extremely valuable when assessing patients with suspected cardiac amyloidosis (CA), but the clinical significance and associated phenotype of different degrees of cardiac uptake across different types is yet to be defined. OBJECTIVES: This study sought to define the phenotypes of patients with varying degrees of cardiac uptake on bone scintigraphy, across multiple types of systemic amyloidosis, using extensive characterization comprising biomarkers as well as echocardiographic and cardiac magnetic resonance (CMR) imaging. METHODS: A total of 296 patients (117 with immunoglobulin light-chain amyloidosis [AL], 165 with transthyretin (TTR) amyloidosis [ATTR], 7 with apolipoprotein AI amyloidosis [AApoAI], and 7 with apolipoprotein AIV amyloidosis [AApoAIV]) underwent deep characterization of their cardiac phenotype. RESULTS: AL patients with grade 0 myocardial radiotracer uptake spanned the spectrum of CMR findings from no CA to characteristic CA, whereas AL patients with grades 1 to 3 always produced characteristic CMR features. In ATTR, the CA burden strongly correlated with myocardial tracer uptake, except in Ser77Tyr. AApoAI presented with grade 0 or 1 and disproportionate right-sided involvement. AApoAIV always presented with grade 0 and characteristic CA. AL grade 1 patients (n = 48; 100%) had characteristic CA, whereas only ATTR grade 1 patients with Ser77Tyr had characteristic CA on CMR (n = 5; 11.4%). After exclusion of Ser77Tyr, AApoAI, and AApoAIV, CMR showing characteristic CA or an extracellular volume of >0.40 in patients with grade 0 to 1 cardiac uptake had a sensitivity and specificity of 100% for AL. CONCLUSIONS: There is a wide variation in cardiac phenotype between different amyloidosis types across different degrees of cardiac uptake. The combination of CMR and bone scintigraphy can help to define the diagnostic differentials and the clinical phenotype in each individual patient

Tracking Multiorgan Treatment Response in Systemic AL-Amyloidosis With Cardiac Magnetic Resonance Derived Extracellular Volume Mapping

Background: Systemic light chain amyloidosis is a multisystem disorder that commonly involves the heart, liver, and spleen. Cardiac magnetic resonance with extracellular volume (ECV) mapping provides a surrogate measure of the myocardial, liver, and spleen amyloid burden. Objectives: The purpose of this study was to assess multiorgan response to treatment using ECV mapping, and assess the association between multiorgan treatment response and prognosis. Methods: The authors identified 351 patients who underwent baseline serum amyloid-P-component (SAP) scintigraphy and cardiac magnetic resonance at diagnosis, of which 171 had follow-up imaging. Results: At diagnosis, ECV mapping demonstrated that 304 (87%) had cardiac involvement, 114 (33%) significant hepatic involvement, and 147 (42%) significant splenic involvement. Baseline myocardial and liver ECV independently predict mortality (myocardial HR: 1.03 [95% CI: 1.01-1.06]; P = 0.009; liver HR: 1.03; [95% CI: 1.01-1.05]; P = 0.001). Liver and spleen ECV correlated with amyloid load assessed by SAP scintigraphy (R = 0.751; P < 0.001; R = 0.765; P < 0.001, respectively). Serial measurements demonstrated ECV correctly identified changes in liver and spleen amyloid load derived from SAP scintigraphy in 85% and 82% of cases, respectively. At 6 months, more patients with a good hematologic response had liver (30%) and spleen (36%) ECV regression than myocardial regression (5%). By 12 months, more patients with a good response demonstrated myocardial regression (heart 32%, liver 30%, spleen 36%). Myocardial regression was associated with reduced median N-terminal pro-brain natriuretic peptide (P < 0.001), and liver regression with reduced median alkaline phosphatase (P = 0.001). Changes in myocardial and liver ECV, 6 months after initiating chemotherapy, independently predict mortality (myocardial HR: 1.11 [95% CI: 1.02-1.20]; P = 0.011; liver HR: 1.07 [95% CI: 1.01-1.13]; P = 0.014). Conclusions: Multiorgan ECV quantification accurately tracks treatment response and demonstrates different rates of organ regression, with the liver and spleen regressing more rapidly than the heart. Baseline myocardial and liver ECV and changes at 6 months independently predict mortality, even after adjusting for traditional predictors of prognosis

Longitudinal strain is an independent predictor of survival and response to therapy in patients with systemic AL amyloidosis

AIMS: Cardiac involvement, a major determinant of prognosis in AL (light-chain immunoglobulin) amyloidosis, is characterized by an impairment of longitudinal strain (LS%). We sought to evaluate the utility of LS% in a prospectively observed series of patients. METHODS AND RESULTS: A total of 915 serial newly diagnosed AL patients with comprehensive baseline assessments, inclusive of echocardiography, were included. A total of 628/915 (68.6%) patients had cardiac involvement. The LS% worsened with advancing cardiac stage with mean −21.1%, −17.1%, −12.9%, and −12.1% for stages I, II, IIIa, and IIIb, respectively (P < 0.0001). There was a highly significant worsening of overall survival (OS) with worsening LS% quartile: LS% ≤−16.2%: 80 months, −16.1% to −12.2%: 36 [95% confidence interval (CI) 20.9–51.1] months, −12.1% to −9.1%: 22 (95% CI 9.1–34.9) months, and ≥−9.0%: 5 (95% CI 3.2–6.8) months (P < 0.0001). Improvement in LS% was seen at 12 months in patients achieving a haematological complete response (CR) (median improvement from −13.8% to −14.9% in those with CR and difference between involved and uninvolved light chain <10 mg/L). Strain improvement was associated with improved OS (median not reached at 53 months vs. 72 months in patients without strain improvement, P = 0.007). Patients achieving an LS% improvement and a standard N-terminal pro-brain natriuretic peptide-based cardiac response survived longer than those achieving a biomarker-based cardiac response alone (P < 0.0001). CONCLUSION: Baseline LS% is a functional marker that correlates with worsening cardiac involvement and is predictive of survival. Baseline LS% and an absolute improvement in LS% are useful additional measures of prognosis and response to therapy in cardiac AL amyloidosis, respectively

Distinct cardiovascular phenotypes are associated with prognosis in systemic sclerosis: a cardiovascular magnetic resonance study

AIMS: Cardiovascular involvement in systemic sclerosis (SSc) is heterogeneous and ill-defined. This study aimed to: (i) discover cardiac phenotypes in SSc by cardiovascular magnetic resonance (CMR); (ii) provide a CMR-based algorithm for phenotypic classification; and (iii) examine for associations between phenotypes and mortality. METHODS AND RESULTS: A retrospective, single-centre, observational study of 260 SSc patients who underwent clinically indicated CMR including native myocardial T1 and T2 mapping from 2016 to 2019 was performed. Agglomerative hierarchical clustering using only CMR variables revealed five clusters of SSc patients with shared CMR characteristics: dilated right hearts with right ventricular failure (RVF); biventricular failure dilatation and dysfunction (BVF); and normal function with average cavity (NF-AC), normal function with small cavity (NF-SC), and normal function with large cavity (NF-LC) sizes. Phenotypes did not co-segregate with clinical or antibody classifications. A CMR-based decision tree for phenotype classification was created. Sixty-three (24%) patients died during a median follow-up period of 3.4 years. After adjustment for age and presence of pulmonary hypertension (PH), independent CMR predictors of all-cause mortality were native T1 (P  0.14). Hazard ratios (HR) were statistically significant for RVF (HR = 8.9, P < 0.001), BVF (HR = 5.2, P = 0.006), and NF-LC (HR = 4.9, P = 0.002) groups. The NF-LC group remained significantly predictive of mortality after adjusting for RVEF, native T1, and PH diagnosis (P = 0.0046). CONCLUSION: We identified five CMR-defined cardiac SSc phenotypes that did not co-segregate with clinical data and had distinct outcomes, offering opportunities for a more precision-medicine based management approach

Sex differences among patients with transthyretin amyloid cardiomyopathy – from diagnosis to prognosis

Aims: transthyretin amyloid cardiomyopathy (ATTR-CM) is predominantly diagnosed in men. The few available studies suggest affected women have a more favourable cardiac phenotype. We aimed to characterize sex differences among consecutive patients with non-hereditary and two prevalent forms of hereditary (h)ATTR-CM diagnosed over a 20-year period. Methods and results: analysis of deep phenotyping at presentation, changes on serial echocardiography and overall prognosis were evaluated. In total, 1732 consecutive patients were studied, comprising: 1095 with wild-type (wt)ATTR-CM; 206 with T60A-hATTR-CM; and 431 with V122I-hATTR-CM. Female prevalence was greater in T60A-hATTR-CM (29.6%) and V122I-hATTR-CM (27.8%) compared to wtATTR-CM (6%). At presentation, females were 3.3 years older than males (wtATTR-CM: 81.9 vs. 77.8 years; T60A-hATTR-CM: 68.7 vs. 65.1 years; V122I-hATTR-CM: 77.1 vs. 74.9 years). Body size significantly influenced measures of disease severity; when indexed, overall structural and functional phenotype was similar between sexes, the few significant differences suggested a mildly worse phenotype in females. No significant differences were observed in both disease progression on serial echocardiography and mortality across the overall population (p = 0.459) and when divided by genotype (wtATTR-CM: p = 0.730; T60A-hATTR-CM: p = 0.161; V122I-hATTR-CM: p = 0.056). Conclusion: this study of a well-characterized large cohort of ATTR-CM patients did not demonstrate overall differences between sexes in either clinical phenotype, when indexed, or with respect to disease progression and prognosis. Non-indexed wall thickness measurements may have contributed to both under-representation and delays in diagnosis for affected females and highlights the potential role of utilizing indexed echocardiographic parameters for a more accurate assessment of patients at diagnosis and for disease prognostication

Clinical Importance of Left Atrial Infiltration in Cardiac Transthyretin Amyloidosis

Objectives: The aim of this study was to characterize left atrial (LA) pathology in explanted hearts with transthyretin amyloid cardiomyopathy (ATTR-CM); LA mechanics using echocardiographic speckle-tracking in a large cohort of patients with ATTR-CM; and to study the association with mortality. Background: The clinical significance of LA involvement in ATTR-CM is of great clinical interest. Methods: Congo red staining and immunohistochemistry was performed to assess the presence, type, and extent of amyloid and associated changes in 5 explanted ATTR-CM atria. Echo speckle tracking was used to assess LA reservoir, conduit, contractile function, and stiffness in 906 patients with ATTR-CM (551 wild-type (wt)-ATTR-CM; 93 T60A-ATTR-CM; 241 V122I-ATTR-CM; 21 other). Results: There was extensive ATTR amyloid infiltration in the 5 atria, with loss of normal architecture, vessels remodeling, capillary disruption, and subendocardial fibrosis. Echo speckle tracking in 906 patients with ATTR-CM demonstrated increased atrial stiffness (median [25th-75th quartile] 1.83 [1.15-2.92]) that remained independently associated with prognosis after adjusting for known predictors (lnLA stiff: HR: 1.23; 95% CI: 1.03-1.49; P = 0.029). There was substantial impairment of the 3 phasic functional atrial components (reservoir 8.86% [5.94%-12.97%]; conduit 6.5% [4.53%-9.28%]; contraction function 4.0% [2.29%-6.56%]). Atrial contraction was absent in 22.1% of patients whose electrocardiograms showed sinus rhythm (SR) “atrial electromechanical dissociation” (AEMD). AEMD was associated with poorer prognosis compared with patients with SR and effective mechanical contraction (P = 0.0018). AEMD conferred a similar prognosis to patients in atrial fibrillation. Conclusions: The phenotype of ATTR-CM includes significant infiltration of the atrial walls, with progressive loss of atrial function and increased stiffness, which is a strong independent predictor of mortality. AEMD emerged as a distinctive phenotype identifying patients in SR with poor prognosis

Impact of Earlier Diagnosis in Cardiac ATTR Amyloidosis Over the Course of 20 Years

Diagnostic and therapeutic advances have led to much greater awareness of transthyretin cardiac amyloidosis (ATTR-CA). We aimed to characterize changes in the clinical phenotype of patients diagnosed with ATTR-CA over the past 20 years

Cardiac transplantation in transthyretin amyloid cardiomyopathy: Outcomes from three decades of tertiary center experience

Aims: Transthyretin cardiac amyloidosis (ATTR-CM) is a progressive and fatal cardiomyopathy. Treatment options in patients with advanced ATTR-CM are limited to cardiac transplantation (CT). Despite case series demonstrating comparable outcomes with CT between patients with ATTR-CM and non-amyloid cardiomyopathies, ATTR-CM is considered to be a contraindication to CT in some centers, partly due to a perceived risk of amyloid recurrence in the allograft. We report long-term outcomes of CT in ATTR-CM at two tertiary centers. Materials and methods and results: We retrospectively evaluated ATTR-CM patients across two tertiary centers who underwent transplantation between 1990 and 2020. Pre-transplantation characteristics were determined and outcomes were compared with a cohort of non-transplanted ATTR-CM patients. Fourteen (12 male, 2 female) patients with ATTR-CM underwent CT including 11 with wild-type ATTR-CM and 3 with variant ATTR-CM (ATTRv). Median age at CT was 62 years and median follow up post-CT was 66 months. One, three, and five-year survival was 100, 92, and 90%, respectively and the longest surviving patient was Censored > 19 years post CT. No patients had recurrence of amyloid in the cardiac allograft. Four patients died, including one with ATTRv-CM from complications of leptomeningeal amyloidosis. Survival among the cohort of patients who underwent CT was significantly prolonged compared to UK patients with ATTR-CM generally (p < 0.001) including those diagnosed under age 65 years (p = 0.008) or with early stage cardiomyopathy (p < 0.001). Conclusion: CT is well-tolerated, restores functional capacity and improves prognosis in ATTR-CM. The risk of amyloid recurrence in the cardiac allograft appears to be low

Progression of echocardiographic parameters and prognosis in transthyretin cardiac amyloidosis

Aims: Transthyretin amyloid cardiomyopathy (ATTR-CM) is an increasingly diagnosed disease. Echocardiography is widely utilized, but studies to confirm the value of echocardiography for tracking changes over time are not available. We sought to describe (i) changes in multiple echocardiographic parameters; (ii) differences in rate of progression of three predominant genotypes; and (iii) the ability of changes in echocardiographic parameters to predict prognosis. Methods and results: We prospectively studied 877 ATTR-CM patients attending our centre between 2000 and 2020. Serial echocardiography findings at baseline, 12 months and 24 months were compared with survival. Overall, 565 patients had wild-type ATTR-CM and 312 hereditary ATTR-CM (201 with V122I; 90 with T60A). There was progressive worsening of structural and functional parameters over time, patients with V122I ATTR-CM showing more rapid worsening of left and right ventricular structural and functional parameters compared to both wild-type and T60A ATTR-CM. Among a wide range of echocardiographic analyses, including deformation-based parameters, only worsening in the degree of mitral (MR) and tricuspid regurgitation (TR) at 12- and 24-month assessments was associated with worse prognosis (change at 12 months: MR, hazard ratio 1.43 [95% confidence interval 1.14–1.80], p = 0.002; TR, hazard ratio 1.38 [95% confidence interval 1.10–1.75], p = 0.006). Worsening in MR remained independently associated with poor prognosis after adjusting for known predictors. Conclusion: In ATTR-CM, echocardiographic parameters progressively worsen over time. Patients with V122I ATTR-CM demonstrate the most rapid deterioration. Worsening of MR and TR were the only parameters associated with mortality, MR remaining independent after adjusting for known predictors