Abstract 694: More Extensive Left Ventricular Hypertrophy in Transthyretin-Type Cardiac Amyloidosis as Compared to Primary Light-Chain Cardiac Amyloidosis

Abstract

Background : Cardiac amyloidosis is generally described as a disease with left ventricular (LV) wall thickening, but data supporting LV morphologic differences between types of amyloidosis are lacking. We sought to examine LV morphologic differences between patients with light chain (AL) and transthyretin (TTR)-type amyloidosis with cardiac involvement using volumetric cardiovascular magnetic resonance (CMR). Methods : Patients with proven AL (n =21) and TTR amyloidosis (n =14) underwent cine CMR using standard methods. Volumetric LV mass, LV volumes, and LV mass/volume ratio were measured by an independent core lab blinded to all patient data, using a contiguous short-axis stack of images covering the left ventricle. Results : Both groups demonstrated a male predominance (TTR 86%, AL 67%) with patients in the TTR group older than AL group (74±8yr vs 61 ± 12yr p=0.002). There were no differences in the degree of heart failure symptoms in the TTR and AL groups: NHYA Class I: 4 vs 5; Class II/III: 9 vs 15; Class IV: 0 vs 1, respectively (p=0.68). The maximum anteroseptal thickness was greater in the TTR group (17.9 ± 3.6mm vs. 14.1 ± 3.3mm; p<0.001). Left ventricular end-diastolic mass was also greater in TTR compared to AL amyloid (236 ± 63g vs. 186 ± 61 g; p=0.02) with no significant difference in LV end-diastolic volume (TTR: 154 ± 32 ml vs. 155 ± 45 ml; p=0.89). The LV mass to volume ratio for TTR amyloidosis was significantly greater than the AL group (1.58 ± 0.5 vs. 1.24 ± 0.4; p=0.02). Conclusions : These data demonstrate that LV morphology differs between TTR and AL cardiac amyloidosis, with increased wall thickness and mass in TTR despite similar baseline symptoms and clinical characteristics. Given the reported more aggressive course of AL vs. TTR cardiac amyloidosis, the clinical significance of these findings needs to be further evaluated.