The influence of autonomic neuropathy on hypotension during hemodialysis

Many patients with chronic renal failure experience profound hypotension during hemodialysis. This phenomenon may be caused by hypovolemia, autonomic or cardiac dysfunction, vascular resistance defects or vasoactive substances such as nitric oxide or adrenomedullin. The aim of the study was to evaluate the influence of autonomic neuropathy on the occurrence of hypotension during hemodialysis. Fifty-three patients with chronic renal failure on maintenance hemodialysis underwent a standard battery of cardiovascular tests for the diagnosis of autonomic neuropathy. The study population was then divided into two groups, with (AN+) and without (AN-) autonomic neuropathy. Blood pressure (BP) was recorded before, during and after hemodialysis for 10 consecutive dialysis sessions and the mean value was calculated.

Of the patients, 38% were AN+. During hemodialysis, systolic BP was lower in AN+ than in AN- patients at the third hour (110.0 +/- 17.5 vs 128.0 +/- 26.2; p = 0.049). Systolic BP reduction during hemodialysis was greater in AN+ than AN-patients (-21.2 +/- 10.9 vs -13.5 +/- 10.6% change, p = 0.013).

The presence of autonomic neuropathy is associated with a more severe BP fall during hemodialysis. Routine evaluation of autonomic function may be helpful in defining patients at risk for dialysis-induced hypotension.