Left Ventricular Structure and Function in Transthyretin-Related Versus Light-Chain Cardiac Amyloidosis

Abstract

Background-Immunoglobulin amyloid light-chain (AL)-related cardiac amyloidosis (CA) has a worse prognosis than either wild-type (ATTRwt) or mutant (ATTRm) transthyretin (TTR) CA. Detailed echocardiographic studies have been performed in AL amyloidosis but not in TTR amyloidosis and might give insight into this difference. We assessed cardiac structure and function and outcome in a large population of patients with CA and compared findings in TTR and AL-related disease. Methods and Results-We analyzed 172 patients with CA (AL amyloidosis, n=80; ATTRm, n=36; ATTRwt, n=56) by standard echocardiography and 2-dimensional speckle-tracking imaging-derived left ventricular (LV) longitudinal (LS), radial, and circumferential strains. Despite a preserved LV ejection fraction (55±12%), LS was severely impaired in CA.Standard measures of LV function and speckle-tracking imaging worsened as wall thickness increased, whereas apical LS was preserved regardless of the pathogenesis of CA and the degree of wall thickening. Compared with ATTRm and AL amyloidosis, ATTRwt was characterized by greater LV wall thickness and lower ejection fraction. LS was more depressed in both ATTRwt and AL amyloidosis (−11±3% and −12±4%, respectively, P=0.54) than in ATTRm (−15±4%, P<0.01 versus AL amyloidosis and ATTRwt). TTR-related causes were favorable predictors of survival, whereas LS and advanced New York Heart Association class were negative predictors. Conclusions-In patients with CA, worsening LV function correlated with increasing wall thickness regardless of pathogenesis.Patients with ATTRwt had a statistically greater wall thickness but lesser mortality than those with AL amyloidosis, despite very similar degrees of LS impairment. This paradox suggests an additional mechanism for LV dysfunction in AL amyloidosis, such as previously demonstrated light-chain toxicity. (Circulation. 2014;129:1840-1849.)

Cardiac Amyloid Imaging with 18F-Florbetaben PET: A Pilot Study

“…Therefore, in the present study, in which AL and ATTR patients had comparable LV mass indices, it is likely that the AL patients had a correspondingly larger extracellular volume and more amyloid deposition than the ATTR patients, as was consequently reflected in a higher myocardial SUV. This finding supports the hypothesis that because of the slower pace of amyloid accumulation, patients with ATTR have time to develop compensatory ventricular muscle hypertrophy, possibly explaining why AL patients have more rapidly progressive heart failure and worse survival than ATTR patients despite relatively less LV mass (20).…”

“…where SUV 0-5 is mean myocardial SUV between 0 and 5 min and SUV [15][16][17][18][19][20] is mean myocardial SUV between 15 and 20 min.…”

Visual Assessment of Relative Apical Sparing Pattern Is More Useful Than Quantitative Assessment for Diagnosing Cardiac Amyloidosis in Borderline or Mildly Increased Left Ventricular Wall Thickness

“…Last, approximately 16.7% of CA patients were unable to be classified into any specific amyloidosis subtype. RapSP-LS, however, had been reported in CA patients regardless of the pathogenesis of CA, 22 and the aim of this study was mainly to compare CA patients with non-CA patients.…”

Echocardiographic Assessment of the Cardiac Amyloidoses

“…56 Additionally, RV function assessed by Doppler myocardial imaging can also radial, and circumferential strains. 69 Compared with ATTRm and AL amyloidosis, ATTRwt was characterized by greater LV wall thickness and lower EF, and the LV longitudinal strain was more depressed in both ATTRwt and AL amyloidosis. TTR-related causes were favorable predictors of survival, whereas longitudinal strain and advanced NYHA class were negative predictors.…”