Echocardiographic parameters in patients with and without hypotension during dialysis

Introduction Intradialytic hypotension (IDH) is a familiar complication of hemodialysis, which increases mortality and morbidity in patients.1 Conforming to the Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines, intradialsis hypotension is the reduction in systolic blood pressure >20 mm Hg or a decrease in mean arterial pressure by 10 mm Hg along with clinical incident and needs for treatment.2 When plasma volume decreases during ultrafiltration, vascular resistance and cardiac output increase to maintain blood pressure. IDH occurs when these mechanisms do not work correctly.3 The decreased sympathetic tone in some patients could reduce arteriolar resistance, increase blood pooling in veins, and ultimately reduce blood pressure.4 A decline in blood volume and insufficient comp ensatory mechanism may cause the underfilling of the heart and activation of Bezold-Jarish reflex and ultimately sudden hypotension.5 Since diastolic dysfunction and LVH reduce ventricular filling and stroke volume, they can contribute to intradialytic hypotension.6, 7 Cardiac disease, including systolic or diastolic function impairement, augments the risk for intradialytic hypotension.8 Demographic risk factors for intradialysis hypotension include older age, diabetes mellitus, longer dialysis vintage, lower pre-dialysis blood pressure, female gender, and higher body mass index.1 Consequences of intradialytic hypotension can range from cramping and post-dialysis fatigue to bowel ischemia, cardiovascular events, stroke, and access thrombosis. Exclusion criteria included acute renal failure, acute coronary syndrome, cerebral ischemic or hemorrhagic infarct within three months, conduction disturbance, pericardial disease, at least moderate valvular heart disease, malignancy, chronic obstructive pulmonary disease (COPD), any uncontrolled metabolic or infectious disease, and low echocardiographic image quality. The upper limit of normal for the LA volume index is 34 mL/m2 in both genders.14 For LV diastolic function, peak E and A-wave velocities, e' velocity, and E/e' ratio were assessed according to a recommendation of ASE.15, 16 Velocity Vector Imaging (VVI) Strain ,as a myocardial deformation index ,is an echocardiographic parameter measured throughout the cardiac cycle , using standard B-mode images for speckle tracking analysis(STE) .17, 18 In 2-dimensional STE, Global Longitudinal Strain (GLS) is the ratio of the maximal longitudinal systolic change in the length of my