Impact of liver transplantation on autonomic neuropathy in familial amyloidotic polyneuropathy: an evaluation by spectral analysis of heart rate variability

Objectives. To evaluate the impact of liver transplantation on familial amyloidotic polyneuropathy type I (FAP) patients' autonomic neuropathy. Design. An open study. Setting. A tertiary referral centre. Subjects. Twelve liver-transplanted FAP patients evaluated before and one year or longer after liver transplantation. Interventions. Spectral analysis of heart rate variability. The low-frequency band after tilting (sympathetic), and the high-frequency band in supine position (parasympathetic) were analysed, as were the pulse and brood pressure reaction to tilting. Clinical symptoms related to autonomic disturbances were recorded. Main outcome measures. Spectral band power for sympathetic and parasympathetic activity. Results. No statistically significant improvements in sympathetic or parasympathetic band power after liver transplantation was found (sympathetic band power: 2.7 (2.2-3.2) before, 2.9 (2.2-3.6) after; parasympathetic 2.0 (1.6-2.4) before and 2.0 (1.7-2.3) after. A significant correlation was noted between orthostatic brood pressure reaction and sympathetic activity before transplantation, but not after the operation. A trend was noted for improved orthostatic blood pressure reaction. Symptomatic improvements in bowel function and orthostatic symptoms were reported by several patients. Conclusions. Although improvements in autonomic symptoms are reported after liver transplantation, no significant improvement is noted in sympathetic or parasympathetic spectral band power of heart rate variability. However, the follow-up period of 17 months may be too short. Further evaluation after an additional two and four years is needed.