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

Background

Wild-type transthyretin cardiac amyloidosis (ATTRwt-CA) occurs at a high prevalence in older patients with left ventricular (LV) hypertrophy. However, detecting ATTRwt-CA using echocardiography is challenging.

Objectives

This study identified echocardiographic findings characterizing ATTRwt-CA compared with monoclonal immunoglobulin light chain cardiac amyloidosis (CA) and hereditary transthyretin CA.

Methods

We conducted a multicenter, retrospective study on the echocardiographic findings characterizing ATTRwt-CA. 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 CA or monoclonal immunoglobulin light chain CA.

Results

Among the cohort, 172 patients (55.3%) were diagnosed with ATTRwt-CA. A multiple discriminant analysis revealed that LV hypertrophy with a more extensive LV mass index but relatively modest interventricular septum thickening and enlargement of maximal papillary muscle diameter were significant echocardiographic findings characterizing ATTRwt-CA. In addition to the patient backgrounds such as advanced age, male sex, concomitant diabetes mellitus, hyperlipidemia, carpal tunnel syndrome, and paroxysmal atrial fibrillation, the discriminant model, including these echocardiographic findings showed significant discriminant power of ATTRwt-CA from the other subtypes (83.8% accuracy with 86.0% positive predictive value and 81.4% negative predictive value, when the sensitivity and specificity are at their maximum values of the model).

Conclusions

In the J-CASE data set, LV hypertrophy with a more extensive LV mass index but relatively modest interventricular septum thickening and enlargement of papillary muscle diameter significantly characterized ATTRwt-CA. These findings may lead to more accurate screening echocardiography for diagnosing ATTRwt-CA and motivate the subsequent comprehensive clinical diagnostic process, including multimodality imaging.