Left atrioventricular coupling index assessed with three-dimensional echocardiography: a prognostic marker of short-term outcomes in light-chain cardiac amyloidosis.

Background: Light-chain cardiac amyloidosis (AL-CA) is associated with structural and functional changes in the left atrium and left ventricle. This study aims to assess the value of the left atrioventricular coupling index (LACI) assessed by three-dimensional echocardiography (3DE) for predicting primary outcome in AL-CA.

Methods: Participants with biopsy-confirmed AL-CA from April 2022 to February 2024 were prospectively analysed. LACI, the ratio of left atrial volume min to left ventricular end-diastolic volumes, was calculated offline using EchoPAC 204. The primary outcome was defined as all-cause death.

Results: Sixty-seven biopsy-proven AL-CA patients were studied (age: 62.98 ± 10.20 years; 67% male). The median follow-up was 121 days (range: 7 ∼ 732 days). All-cause mortality occurred in 26 (39%) patients. Multivariate Cox regression revealed a significant association of LACI after adjusting for NT-pro BNP, troponin T, moderate tricuspid regurgitation, pericardial and pleural effusion (adjusted HR: 10.58, p = 0.008). Kaplan-Meier curves displayed prognostic differences based on median LACI (cut-off : 0.57, p = 0.002). The likelihood ratio χ2 test showed that LACI added predictive value to Mayo 2004, European 2015 modification of Mayo 2004, and Mayo 2012 models (All p < 0.001).

Conclusions: 3DE-based LACI is independently associated with all-cause mortality in AL-CA patients and augments prognostic value to traditional staging models.