Continuous recording of muscle nerve sympathetic activity during percutaneous transluminal angioplasty in renovascular hypertension in man.

We have previously shown that during percutaneous transluminal renal angioplasty (PTRA) there is a transient increase in plasma renin activity (PRA) that is partly mediated by adrenergic beta-receptors. Despite a concomitant increase in plasma aldosterone, no increase in blood pressure occurred. The aim of this study was to record sympathetic outflow in man during PTRA as reflected by muscle nerve sympathetic activity and arterial plasma noradrenaline. Nine patients with hypertension and unilateral renal artery stenosis underwent PTRA by the Grüntzig technique and simultaneous microelectrode recording of muscle nerve sympathetic activity in the peroneal nerve. Blood pressure and heart rate were recorded and blood specimens were drawn for determination of noradrenaline and PRA. During total occlusion of the renal artery, muscle nerve sympathetic activity and the heart rate were unchanged. In the first 6 min after occlusion PRA increased transiently, but there was no significant change in muscle nerve sympathetic activity, arterial noradrenaline, heart rate or blood pressure. From 10 min after PTRA, muscle nerve sympathetic activity was significantly increased and after 40 min there was a significant increase in noradrenaline. The heart rate remained unchanged throughout the procedure, but the blood pressure decreased progressively and the diastolic blood pressure was significantly reduced at 40 min, indicating successful dilation. Despite activation of the renin-angiotensin-aldosterone system and the sympathetic nervous system, two strong pressor systems, the only circulatory reaction was a decrease in diastolic blood pressure. These findings indicate simultaneous activation of a potent depressor mechanism during PTRA.