The impact of left ventricular preload reduction on cardiac pulsed Doppler indices during hemodialysis and its relation to intra-dialysis hypotension: a pulsed Doppler study

Abstract

Fluid status in the body plays an important role on left ventricular (LV) filling in patients with end-stage renal disease (ESRD) on regular hemodialysis (HD), and plays a role in intra-dialysis hemo-dynamic derangement. Fifty-two patients with ESRD on regular HD, including 34 males with a mean age of 45.5 +/- 13 years (range 18-72 years), were studied. All patients underwent Echo-pulsed Doppler study before and immediately after a HD session. The Echo Doppler indices noted were: LV cavity dimension and wall thickness, LV ejection fraction (LVEF%), trans-mitral early diastolic filling velocity (E wave), atrial filling diastolic velocity (A wave), E/A ratio, Deceleration Time (DT) of E wave, Isovolumic relaxation time (IVRT), Aortic Velocity Integral (AVI) and Inferior Vena Cava Diameter (VCD) at expiration. Patients were divided into two groups according to the amount of net ultra filtrate loss after HD. Group I comprised of 25 patients with fluid loss of > or = 2 liters. During the HD session, each patient was observed for the development of acute clinical events such as arterial hypotension (systolic BP less than 90 mmHg), chest pain and arrhythmias. There was a significant difference between the two groups in the mean values, pre- and post- HD, of reduction of E wave velocity (p< 0.01), the reduction of E/A ratio (p< 0.05), the increment in DT of E wave (p< 0.05), the reduction in AVI (p< 0.01) and the reduction of VCD (p< 0.05). There was no significant difference between the groups in the reduction of A wave velocity and the reduction of IVRT. Among the study patients, 11 (21%) developed systolic hypo-tension during HD. The pre-dialysis mean values of E/A ratio and DT of E wave in patients who developed hypotension compared to those who did not was 0.7 +/- 0.2 vs 1.1 +/- 0.2.1 (p< 0.001) and 246 +/- 40 vs 224 +/- 34 msec (p< 0.05), respectively. Our study suggests that preload reduction in patients with ESRD on regular HD is directly proportional to the reduction of left ventricle early filling and prolongation of Deceleration Time of E wave. The potential risk of intra-dialysis hypotension can be predicted, if LV diastolic Pulse Doppler pre-dialysis E/A ratio is less than 0.7 and Deceleration Time of E wave is more than 246 msec. Careful assess-ment of these patients is crucial to prevent hypotension, especially if a large preload reduction is required.