Prognostic value of left atrial strain in patients with chronic moderate-to-severe aortic regurgitation

Introduction Left atrial reservoir phase occurs when the left atrium fills with blood from the pulmonary veins. This can be measured using the left atrial reservoir strain (LASr). In chronic aortic regurgitation, volume and pressure overload caused by regurgitant flow may impair left atrial relaxation and filling. We performed this study to investigate the prognostic significance of LASr in patients with chronic moderate-to-severe aortic regurgitation Methods Patients with moderate-to-severe aortic regurgitation were retrospectively identified from January 2020 to June 2020 from a university hospital. Baseline clinical and echocardiographic parameters were evaluated. LASr was measured using speckle-tracking analysis. Receiver operating characteristic (ROC) curve was constructed and area under the curve (AUC) was calculated. Univariate and multivariable Cox proportional hazard analysis were performed. The primary endpoint was all-cause mortality. Kaplan-Meier (KM) analysis was used to determine cumulative overall survival. Results Among the 124 patients (Age 66.7 ± 14.8 years; 26% female), the mean left ventricular ejection fraction was 59.9% ± 10.7. The median follow-up during medical surveillance was 3.27 years; during which 31 patients (25%) died. ROC curve showed that the AUC of LASr for overall mortality was 0.678 (p=0.004) and the best cut off value was 24 % (Sensitivity 73.3%, Specificity 50%). LASr <24% was observed in 40 patients (32.2%). Impaired LASr was then defined as <24%. Patients with LASr <24% compared with LASr >=24% were older (Age >75: 50% vs 26.2%, p=0.009), female (40.0% vs 20.2%, p=0.020), were more likely to have atrial fibrillation (20.0% vs 4.8%, p=0.007), diabetes (27.5% vs 10.7%, p=0.018) and chronic kidney disease (27.5% vs 9.5%, p=0.009). Compared with patients with LASr >=24%, those with LASr <24% had poorer LV systolic function (LVEF <55%: 35.0% vs 17.9%, p=0.035), higher pulmonary pressure (RVSP >=40mmHg: 35% vs 9.5%, p=0,001), and higher left ventricular filling pressure (E/e’: 12.6(3.7) vs 10.7 (2.3), p=0.034). On multivariate Cox regression, impaired LASr (adjusted hazard ratio 2.316 (1.107-4.843), p=0.026) was associated with all-cause mortality after adjustment. Using KM analysis showed that overall survival in patients with LASr <24% were significantly poorer than LASr >=24% (log rank test p=0.013). Conclusion Impaired LASr is a prognostic predictor in patients with chronic moderate-to-severe aortic regurgitation and may be a useful marker to guide treatment.