Risk Factors and Prognostic Role of Left Atrial Enlargement in Patients with Cardiac Light-Chain Amyloidosis

BackgroundLight-chain amyloidosis (AL) is a plasma cell disorder characterized by the extracellular deposition of insoluble fibril-forming monoclonal immunoglobulin, aggregating in heart and leading to cardiac amyloidosis (CA). Transthoracic echocardiography is a noninvasive method used for the evaluation of cardiac diastolic dysfunction. The left atrium (LA) plays an important role in modulating cardiovascular performance, with its function participating left ventricular filling and its size being affected by diastolic function. Therefore, we aimed to assess prognostic values of LA size measured by a simple echocardiographic parameter, LA diameter indexed to body surface area, in CA and to explore risk factors associated with LA enlargement as well as the incidence of severe heart failure (HF).Materials and MethodsA retrospective analysis of echocardiography of patients with biopsy-proven cardiac AL amyloidosis was conducted. LA enlargement was defined as LA diameter indexed to body surface area greater than 23 mm/m2.ResultsA total of 104 patients with CA were included in the final analysis, 61 (58.7%) of which showed a presentation of LA enlargement. Age, New York Heart Association, ejection fraction and early-to-atrial transmitral flow velocity ratio were independently associated with LA enlargement. During a mean follow-up period of 39 months, LA enlargement was strongly related with all-cause mortality (hazard ratio = 1.94; 95% CI: 1.14-3.29; P = 0.015) and increased risk of severe HF (hazard ratio = 2.18; 95% CI: 1.12-4.23; P = 0.022).ConclusionsIn cardiac AL amyloidosis, age and early-to-atrial transmitral flow velocity ratio were main independent risk factors with regard to LA enlargement. LA enlargement was strongly associated with incidence of severe HF and was also a significant predictor of all-cause mortality.