Thoracic sympathectomy: effects on hemodynamics and baroreflex control.

UNLABELLED: Endoscopic thoracic sympathectomy at T2-T4 is an effective and safe treatment for primary axillary and palmar hyperhidrosis and facial blushing refractory to conventional treatment. T2 and T4 ganglia however are in the direct pathway of sympathetic innervation of the heart and part of the vasomotor nerves. In this study we investigate possible changes in steady-state hemodynamics as well as in beat-to-beat cardiovascular control after thoracoscopic sympathectomy of T2-T4. In 12 patients we measured continuously heart rate (HR) and blood pressure (BP) (non-invasively with Finapres) during rest and during deep inspiration, in supine and sitting position as well as during a change from lying to standing. Stroke volume (SV) and total peripheral resistance (TPR) were estimated from the BP recordings by the Modelflow method. Markers for cardiovascular control were obtained from power and cross-spectra of BP and HR. After sympathectomy, only in the sitting position was mean HR decreased, while TPR and BP (diastolic and mean) were lower in the supine as well as sitting positions. SV clearly increased. Low frequency power in HR and BP was significantly decreased, just like the max/min ratio in HR after standing up, indicating a diminished capacity in sympathetic vasomotor control. High frequency power of HR as well as baroreflex sensitivity, both parasympathetic markers, did not change in a statistically significant manner.
CONCLUSION: Besides altering steady-state hemodynamics, a thoracic sympathectomy causes relatively small, though measurable changes in cardiovascular control, in particular of peripheral vasomotion.