Autonomic Dysfunction in Chronic Renal Failure

Lee, Sang Ho; Choi, Soo Chul; Hong, Seoung Pyo; Lee, Tae Won; Lim, Chun Gyu; Kim, Myung Jae

Abstract

OBJECTIVES
: Impaired autonomic function in patients with chronic renal failure has been well documented in a number of studies to assess the degree of cardiovascular autonomic dysfunction and to assess the relationship with plasma catecholamines. The purpose of the present study was to evaluate the prevalence of autonomic dysfunction and to determine the effect of autonomic dysfunction on the increment of plasma catecholamine, dialysis-induced hypotension and hypotension during chronic dialysis.
METHODS
We measured the degree of autonomic damage and the concentration of plasma catecholamines in 20 patients on maintenance hemodialysis, 12 pre- dialysis patients with chronic renal failure and 20 normal controls using a standardized battery of five cardiovascular reflex tests.
RESULTS
1) In normal controls, 70% of cases had a normal or early parasympathetic abnormalities however in patients with chronic renal failure, 45.2% of patients had severe abnormalities. The prevalence of autonomic dysfunction was 62.5% and there was significant correlation between sympathetic and parasympathetic score in patients with chronic renal failure. 2) Although overall autonomic function was not different in two chronic renal failure groups, the magnitude of heart rate response to Valsalva maneuver was increased and the magnitude of fall of blood pressure in response to standing-up was reduced in dialyzed patients compared with nondialyzed patients. 3) Patients with autonomic dysfunction was older and had higher postdialysis concentration of plasma norepinephrine than those with normal autonomic function. 4) In dialyzed patients, predialysis concentration of plasma norepinephrine at rest varied widely and was significantly related to the duration of dialysis. Postdialysis concentration of norepinephrine was significantly correlated with the degree of parasympathetic damage. 5) There were no significant differences in autonomic damage or plasma catecholamines whether dialysis- induced hypotension and hypotension in chronic hemodialysis or not.
CONCLUSION
: Disturbances of autonomic nerve system are common in chronic renal failure with distinct abnormalities of parasympathetic function and additional sympathetic dysfunction. Elevated plasma norepinephrine seems to be related to the compensatory response of sympathetic nerve system to parasympathetic damage. Impairment of autonomic function does not appear specifically related to dialysis-induced hypotension or hypotension in chronic dialysis.