Synergic Impact of Vascular Calcification and Low Autonomic Tone in Mortality of Hemodialysis Patients.

BACKGROUND: Both cardiovascular calcification and autonomic dysfunction are frequently encountered in hemodialysis patients. We aimed to investigate the relationship between cardiovascular calcification and heart rate variability (HRV) and their influence on long-term outcome.

METHODS: Seventy-eight hemodialysis patients underwent echocardiogram and radiography of the pelvis and hands to identify valvular and vascular calcification. HRV was evaluated using a commercial machine.

RESULTS: Based on the average, the patients were divided into higher and lower subgroups of high frequency (HF) and low frequency (LF) respectively. Patients with higher LF were younger and were found to have a lower proportion of diabetes. Their hemoglobin, albumin, and bone morphogenic protein (BMP)-7 levels were significantly higher and both high-sensitive C-reactive protein (hs-CRP) and osteoprotegerin levels were lower (all p < 0.05). In patients of the higher HF group, the proportion of diabetes was lower but they were found to have higher levels of BMP-7 and lower levels of hs-CRP, interleukin-6 (all p < 0.05). Significantly higher LF and HF were noted in patients without vascular calcification, but only hand artery (HA) calcification was negatively correlated with both LF and HF in multivariate analysis. Low LF and high hs-CRP were the independent predictors of mortality. Coexistence of low LF band and HA calcification was associated with the worse outcome.

CONCLUSIONS: Abnormal autonomic nervous function was closely related to inflammation and mortality in hemodialysis patients. Calcification of HA was associated with autonomic dysfunction and patients with lower autonomic tone and HA calcification had the highest mortality rate in this population.