MR 4D flow–derived left atrial acceleration factor for differentiating advanced left ventricular diastolic dysfunction.

Objectives: The magnetic resonance (MR) 4D flow imaging–derived left atrial (LA) acceleration factor α was recently introduced as a means to non-invasively estimate LA pressure. We aimed to investigate the association of α with the severity of left ventricular (LV) diastolic dysfunction using echocardiography as the reference method. Methods: Echocardiographic assessment of LV diastolic function and 3-T cardiac MR 4D flow imaging were prospectively performed in 94 subjects (44 male/50 female; mean age, 62 ± 12 years). LA early diastolic peak outflow velocity (vE), systolic peak inflow velocity (vS), and early diastolic peak inflow velocity (vD) were evaluated from 4D flow data. α was calculated from α = vE / [(vS + vD) / 2]. Mean parameter values were compared by t-test; diagnostic performance of α in predicting diastolic (dys)function was investigated by receiver operating characteristic curve analysis. Results: Mean α values were 1.17 ± 0.14, 1.20 ± 0.08, 1.33 ± 0.15, 1.77 ± 0.18, and 2.79 ± 0.69 for grade 0 (n = 51), indeterminate (n = 9), grade I (n = 13), grade II (n = 13), and grade III (n = 8) LV diastolic (dys)function, respectively. α differed between subjects with non-advanced (grade < II) and advanced (grade ≥ II) diastolic dysfunction (1.20 ± 0.15 vs. 2.16 ± 0.66, p < 0.001). The area under the curve (AUC) for detection of advanced diastolic dysfunction was 0.998 (95% CI: 0.958–1.000), yielding sensitivity of 100% (95% CI: 84–100%) and specificity of 99% (95% CI: 93–100%) at cut-off α ≥ 1.58. The AUC for differentiating grade III diastolic dysfunction was also 0.998 (95% CI: 0.976–1.000) at cut-off α ≥ 2.14. Conclusion: The 4D flow–derived LA acceleration factor α allows grade II and grade III diastolic dysfunction to be distinguished from non-advanced grades as well as from each other. Clinical relevance statement: As a single continuous parameter, the 4D flow–derived LA acceleration factor α shows potential to simplify the multi-parametric imaging algorithm for diagnosis of advanced LV diastolic dysfunction, thereby identifying patients at increased risk for cardiovascular events. Key Points: • Detection of advanced diastolic dysfunction is typically performed using a complex, multi-parametric approach. • The 4D flow–derived left atrial acceleration factor α alone allows accurate detection of advanced left ventricular diastolic dysfunction. • As a single continuous parameter, the left atrial acceleration factor α could simplify the diagnosis of advanced diastolic dysfunction. [ABSTRACT FROM AUTHOR]