Echocardiographic Features of Wild-Type Transthyretin Cardiac Amyloidosis From J-Case

Figures

• 

  Figure 1. Case Inclusion in the Study Cohort In this multicenter retrospective cohort study with 18 participating institutions in Japan, 359 patients from 2000 to 2020 with histological amyloid deposition suspected of cardiac amyloidosis (CA) were screened. After excluding 35 patients caused by only histologically proven amyloid deposition other than in the myocardium, we evaluated 324 patients with histologically proven amyloid deposition in the myocardium by myocardial biopsy. The subtype classification of CA was determined based on amyloid immunostaining. Transthyretin cardiac amyloidosis (ATTR-CA) patients with confirmed TTR gene abnormalities were also classified as having hereditary/variant transthyretin cardiac amyloidosis (ATTRv-CA). We excluded 13 patients with subtypes of CA other than monoclonal immunoglobulin light chain cardiac amyloidosis (AL-CA) and ATTR-CA; therefore, we enrolled 311 patients in this study. ATTRwt-CA = wild-type transthyretin cardiac amyloidosis.

• 

  Figure 2. Comparison of Echocardiographic Findings Between ATTRwt-CA and AL-CA Typical echocardiographic findings of ATTR-CA and AL-CA are shown. Compared with the AL-CA group, the ATTRwt-CA group showed significant left ventricular hypertrophy with significantly larger interventricular septum thickness, posterior wall thickness, and left ventricular mass index (A vs G); mitral papillary muscle hypertrophy with significantly larger maximal muscle diameter (B vs H); enlargement of right ventricle with larger basal right ventricular end-diastolic diameter (C vs I) but no significant difference in right ventricular wall thickness (E vs K); and both atrial sizes with significantly larger left atrial volume index and right atrial end-systolic area (D vs J). Notably, compared with those with AL-CA, a significantly smaller proportion presented normal left ventricular wall thickness (interventricular septum thickness and posterior wall thickness ≤ 12 mm) (A vs G). The left ventricular systolic and diastolic function parameters and left atrial strain parameters were not different from those of the AL-CA group. In contrast, their apical-sparing index tended to be higher than the AL-CA group (F vs…

• 

  Figure 3. Diagnostic Performance of the Discriminant Model of ATTRwt-CA (A) This figure shows a diagnostic performance plot (DP-plot) of the model with discriminant factors with F-value ≥2.0 in the multiple discriminant analysis. The DP-plot diagram demonstrates the sensitivity (red dot) and the specificity (blue dot) when the threshold value is changed from the minimum to the maximum value of the actual data and the theoretical sensitivity (red line), specificity (blue line), and discriminant accuracy (green line) when it is assumed that the data of the 2 groups are normally distributed. When the sensitivity and specificity are at their maximum values (black arrow), the discriminant model demonstrated 83.8% discriminant accuracy with 86.0% positive predictive value and 81.4% negative predictive value. (In this point, the theoretical sensitivity, specificity, and discriminant accuracy are the same.) (B) The receiver-operating characteristic (ROC) curve at the optimal discriminant score where the theoretical sensitivity and specificity match. The actual ROC curve from the minimum to the maximum value of the discrimination score is shown as a solid black line, and the theoretical ROC curve…

• 

  Central Illustration. Echocardiographic Features of Wild-Type Transthyretin Cardiac Amyloidosis J-CASE (Japan Cardiac Amyloidosis Survey of typical Echocardiographic findings) analyzed echocardiographic data in 311 patients with histologically proven amyloid deposition in the myocardium and diagnosis of transthyretin cardiac amyloidosis or monoclonal immunoglobulin light chain cardiac amyloidosis to investigate the echocardiographic findings characterizing wild-type transthyretin cardiac amyloidosis (ATTRwt-CA). The multiple discriminant analysis revealed that, in addition to the patient background, such as advanced age, male sex, diabetes mellitus, hyperlipidemia, carpal tunnel syndrome, and paroxysmal atrial fibrillation, the study found that echocardiographic findings of left ventricular hypertrophy with increased left ventricular mass index (LVMI) but relatively modest interventricular septum thickness (IVS) thickening, and enlargement of maximal papillary muscle diameter demonstrated discriminant power of ATTRwt-CA from monoclonal immunoglobulin light chain cardiac amyloidosis and hereditary/variant transthyretin cardiac amyloidosis. According to the figure showing a diagnostic performance plot…