367 Left Atrial Reservoir Strain by Speckle Tracking Echocardiography: A Powerful Determinant of Exercise Capacity in Chronic Kidney Disease

Patients with chronic kidney disease (CKD) have impaired physical function and reduced exercise capacity, both factors associated with increased cardiovascular risk. The aim of our study was to evaluate the role of left atrial reservoir strain (LAs) as a determinant of exercise capacity in CKD patients. Patients with Stage 3/4 CKD were prospectively recruited from outpatient nephrology clinics and underwent detailed clinical evaluation, electrocardiogram, resting and exercise stress echocardiogram. All recruited patients had no prior cardiac history, had stable CKD, were in sinus rhythm and did not have myocardial ischaemia on stress testing. Patients with impaired left ventricular ejection fraction (LVEF), greater than mild valvular heart disease or significant mitral annular calcification were excluded. A total of 218 (63.9±11.7yrs, 64% men) CKD patients with stable renal function were recruited. Clinical correlates of exercise capacity included age (p<0.01), eGFR (p<0.01), BMI (p<0.01) and gender (p<0.01). Amongst echocardiographic parameters, LA function by LAs (r=0.72, p<0.01) demonstrated the strongest correlation to METs achieved with exercise and was the only echocardiographic parameter that predicted METs on multivariable analysis (p<0.01). Measures of LV volume, mass and function including LVEF and LV global longitudinal strain, as well as LA parameters including LA emptying fraction and indexed LA volume, did not predict exercise capacity. In stable Stage 3/4 CKD patients without cardiac disease, LAs was the only independent echocardiographic predictor of exercise capacity, a recognised determinant of cardiovascular prognosis. Use of LAs may serve as biomarker in risk stratification in this population.