What is the role of echocardiography in the workup of cardiac amyloidosis?

Updated: Mar 25, 2020
  • Author: Gyanendra K Sharma, MD, FACC, FASE; Chief Editor: Terrence X O'Brien, MD, MS, FACC  more...
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Answer

Two-dimensional transthoracic echocardiography (2D-TTE) [41, 42, 43] is most commonly used in the initial assessment [44] and may reveal the following abnormalities:

  • Left ventricular (LV) thickening (most common) in the absence of hypertension is highly suggestive of an infiltrative heart disease (not specific for amyloidosis and also seen in other conditions, such as sarcoidosis, hemochromatosis, and glycogen storage diseases). Lack of LV hypertrophy (LVH) on electrocardiography (ECG) and septal thickness greater than 1.98 cm had a sensitivity of 72% and specificity of 91% to detect amyloidosis. [45]

  • LV myocardium has granular or sparkling appearance (poor sensitivity: seen only in 26% cases; see the images below).

    Long axis parasternal view: Left ventricular hypertrophy (LVH) with sparkling appearance, pericardial effusion.

     

    Short axis view: Left ventricular hypertrophy (LVH), pericardial effusion, normal RV size.
  • Normal or small LV cavity dimensions is seen.

  • Preserved LV ejection fraction (LVEF) is common, and reduced LV systolic function is seen late in the course of the disease.

  • Impairment of long axis contraction is seen early. This can be shown on abnormalities of strain rate imaging. [46]

  • Diastolic dysfunction is the hallmark of the disease and progresses over time, resulting in restrictive mitral in-flow filling pattern on Doppler evaluation. [47, 48] Tissue Doppler imaging of the mitral annulus shows reduced diastolic velocities with cardiac amyloidosis and is useful to differentiate it from constrictive physiology, in which early diastolic mitral annular velocity (E') is above 8 cm/s. [49]  Longitudinal strain of the LV basal segments and E/e' ratio (the ratio between early mitral inflow velocity and mitral annular early diastolic velocity) can help to differentiate primary cardiac amyloidosis from hypertensive LVH. [50]  Investigators found that cardiac amyloidosis was predicted by basal longitudinal strain of -11.3% or below (63.3% sensitivity, 100% specificity) and an E/e' of 12.3 or greater (69.7% sensitivity, 83.3% specificity). [50]  Longitudinal strain can also be used as a measure of pretreatment cardiac functional impairment in light chain cardiac amyloidosis; in addition, it can predict survival and early cardiac functional improvement following chemotherapy. [51]

  • Right ventricular (RV) hypertrophy (RVH)

  • RV dilatation (a marker of poor prognosis): RV dysfunction is common in cardiac amyloidosis, and a tricuspid annular plane systolic excursion (TAPSE) below 14 mm is an independent predictor of adverse cardiac events. [52]  Independent determinants of TAPSE below 14 mm are LVEF, E/E', N-terminal pro b-type natriuretic peptide (NT-proBNP) levels, and pulmonary artery pressure, but not RV late gadolinium-enhancement (LGE) on cardiac magnetic resonance imaging (CMRI). [52]

  • Left atrial enlargement, biatrial enlargement (late): Left atrial size is an independent predictor of overall survival in patients with primary systemic amyloidosis [53] ; the extent of left atrial LGE on CMRI is highly predictive for cardiac amyloidosis. [54]

  • Thickened interatrial septum

  • Thickened atrioventricular valves

  • Small pericardial effusion

Three-dimensional speckle tracking TTE (3D-TTE) may allow earlier detection of LV systolic dysfunction in patients with systemic light-chain amyloidosis than 2D-TTE. [44] In a study of 58 patients with confirmed light chain amyloidosis and 21 healthy control subjects, investigators noted 3D-TTE demonstrated significantly worse LV systolic function in Mayo Clinic (MC) stage II and III patients compared to control subjects, and that MC III patients had significantly worse global circumferential strain and area tracking. In addition, although 2D-TTE revealed apparently preserved LVEF in patients with light chain amyloidosis in MC stage II and III, 3D-TTE showed evidence of LV systolic dysfunction using LVEF and strain analysis. Worse LV involvement by light chain amyloidosis was associated with more impaired 3D-TTE LV systolic parameters. [44]


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