Association of left atrial strain and stiffness index with ascending aortic dilatation in patients with bicuspid aortic valve

Background Left atrial stiffness index (LASI) is an emerging echocardiographic index that reflects left atrial–left ventricular functional coupling and diastolic dysfunction. However, the relationships of left atrial strain parameters and LASI with ascending aortic dilatation (AAD) in patients with bicuspid aortic valve (BAV) remain unclear. This study aimed to investigate the associations of left atrial strain parameters and LASI with the presence of AAD and to evaluate their ability to discriminate between BAV patients with and without AAD. Methods and results This retrospective study included 86 patients with BAV and 40 healthy controls. Left atrial reservoir strain (LASr), conduit strain (LAScd), and contraction strain (LASct) were measured, and LASI was calculated. Based on the aortic size index (ASI), patients with BAV were classified into a nondilated group (ASI ≤ 2.1 cm/m 2 ) and a dilated group (ASI > 2.1 cm/m 2 ). In ROC curve analyses, LASr, E/e′ (the ratio of early transmitral flow velocity to early diastolic mitral annular velocity), and LASI demonstrated discriminatory ability for the presence of AAD in patients with BAV, with AUCs of 0.792, 0.783, and 0.871, respectively. The corresponding data-derived optimal cutoff values were 23.44%, 8.17, and 0.30. Multivariable binary logistic regression analysis showed that LASr < 23.44%, E/e′ > 8.17, and LASI > 0.30 were independently associated with the presence of AAD in patients with BAV. When LASI was added to the baseline model comprising E/e′ and LASr, the likelihood-ratio χ 2 increased from 41.88 to 45.84 ( Δχ 2 = 3.96, P = 0.047), with a continuous net reclassification improvement of 0.571 (95% CI, 0.193–0.950; P = 0.003). Conclusions LASI was associated with the presence of AAD in patients with BAV and provided incremental discriminatory information within the study sample. As a simple echocardiographic index integrating an estimate of left ventricular filling pressure with left atrial reservoir function, LASI may provide complementary information on left atrial–left ventricular functional alterations in BAV patients with AAD.