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 blood 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 blood 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.