Abstract 12992: LA Strain Predicts Exercise Capacity in Chronic Kidney Disease

Abstract

Background: Left atrial (LA) function plays a pivotal role in modulating left ventricular performance particularly during exercise. The aim of our study was to evaluate the relationship between resting LA function by strain analysis as a determinant of exercise capacity in chronic kidney disease (CKD) patients, and evaluate its utility compared to exercise E/e’. Methods: Consecutive Stage 3 and 4 CKD patients without prior cardiac history were prospectively recruited from outpatient nephrology clinics and underwent clinical evaluation, resting and exercise stress echocardiography. Patients needed to be in sinus rhythm without significant valvular disease or ischaemia on stress testing. Resting echocardiographic parameters including E/e’ and phasic LA strain [LA reservoir (LASr), conduit (LAScd) and contractile (LASct) strain] were measured and compared to exercise E/e’. Results: 218 (63.9±11.7yrs, 64% men) CKD patients were recruited. Independent clinical predictors of exercise capacity were age, eGFR, body mass index and gender (p<0.01 for all) while independent resting echocardiographic predictors included E/e’, LASr and LASct (p<0.01 for all). Amongst independent resting echocardiographic predictors, LASr ( r =0.70,p<0.01) demonstrated the strongest correlation to METs achieved. Receiver operating characteristic curves (Figure 1) demonstrated that LASr (AUC 0.83,) had similar predictive value as exercise E/e’ (AUC 0.79; AUC difference of 0.05, p=0.20 on DeLong test). A model combining LASr and clinical metrics showed robust predictive capacity for METs achieved in CKD patients. Conclusions: LASr, a marker of decreased LA compliance is an independent predictor of exercise capacity in Stage 3 and 4 CKD patients, with similar predictive value to exercise E/e’. The use of LASr may serve as a resting biomarker of functional capacity in this population.