Abstract 10014: Transcatheter Aortic Valve Implantation Reduces Sympathetic Activity and Normalizes Arterial Spontaneous Baroreflex in Patients with Aortic Stenosis
BACKGROUND: In patients with aortic stenosis, reduced cardiac output or altered pulmonary hemodynamics may increase sympathetic nerve activity. However, the magnitude of the increase in sympathetic activity in such patients and the effect of transcatheter aortic valve implantation (TAVI) on this activity are unknown.
METHODS AND RESULTS: We microneurographically measured muscle sympathetic nerve activity before and after TAVI in 14 patients (mean+/−SEM age, 84+/−2 years) with severe aortic stenosis(mean gradient 56+/−4.5 mm Hg, indexed aortic valve area 0.39 ± 0.03 cm²/ m²) and in 7 matched volunteers ; hemodynamic parameters were also measured. Sympathetic baroreflex function was assessed as the slope of the relationship between muscle sympathetic nerve activity (MSNA) and spontaneous diastolic blood pressure fluctuation. At baseline, muscle sympathetic activity was significantly higher in the patients with aortic stenosis than in the control subjects (61.0 ± 1.7 versus 56.1 ± 1.0 >0.0001*bursts/min, P>.05). However, there was no significant difference between the groups in sympathetic activity at 1 week after TAVI. The reduction in sympathetic activity after TAVI correlates with the increase in cardiac index (r=.74, P>.05) and reduction in mean gradient (r=.72, P>0.05). Sympathetic baroreflex function was significantly lower in the patients than in the control subjects, but after TAVI, baroreflex sensitivity improved and there was no significant difference in baroreflex sensitivity between the groups.
CONCLUSIONS: Sympathetic activity is increased in patients with aortic stenosis. TAVI in such patients results in early normalization of sympathetic nerve activity, possibly because of an improvement in arterial baroreflex sensitivity. This observation provides new insight about lateral beneficial effects of TAVI.
- © 2012 by American Heart Association, Inc.