Reduced spontaneous baroreceptor sensitivity in patients with renovascular hypertension

OBJECTIVE: Sympathetic nerve activity is increased in hypertensive patients with renal artery stenosis. Less is known about cardiac vagal function in these patients before and after renal angioplasty. The aim of the present study was to investigate cardiac baroreceptor reflex sensitivity together with total body noradrenaline (NA) spillover in hypertensive patients with renal artery stenosis before, and in some patients, 1 year after renal angioplasty. MATERIAL AND METHODS: Spontaneous baroreceptor reflex sensitivity and total body noradrenaline (NA) spillover were measured in patients with renovascular hypertension before intervention (n = 18), patients being cured/improved 1 year after renal angioplasty (n = 5) and age-matched healthy subjects (n = 25). RESULTS: Hypertensive patients with renal artery stenosis had higher total body NA spillover (4630 +/- 619 versus 3132 +/- 210 pmol/min, P < 0.05) and reduced cardiac baroreceptor reflex sensitivity (6.1 +/- 1.0 versus 10.7 +/- 1.0 ms/mmHg, P < 0.01) compared with healthy subjects. Similar results were obtained (before intervention) in a subgroup of patients (n = 9) with renovascular hypertension defined as cured/improved 1 year following renal angioplasty. Baroreceptor reflex sensitivity improved after renal angioplasty in a subset of patients showing good blood pressure control 1 year after intervention (6.4 +/- 0.7 to 9.4 +/- 1.7 ms/mmHg, P < 0.05). CONCLUSIONS: Patients with renovascular hypertension showed reduced cardiac baroreceptor reflex sensitivity and increased noradrenergic activity, which to some extent was reversed 1 year following successful renal angioplasty.