ABSTRACT
OBJECTIVES: In renal denervation (RDN), a wide range in the blood pressure (BP)-lowering effect has been reported. On the basis of the current knowledge of pathophysiology, we hypothesized that the BP-lowering effect of RDN would be inversely related to kidney function. Second, we investigated whether direct and indirect variables of the renin-angiotensin-aldosterone system (RAAS) and the sympathetic nervous system (SNS) would be related as well. METHODS: Sixty-seven patients from a prospective cohort of patients treated with RDN with completed 6 months follow-up were included. Data collected during routine standardized work-up before RDN were used: 24-h urine excretion of creatinine, albumin, sodium and catecholamines, plasma creatinine, renin activity and aldosterone, ambulatory BP-monitoring and a captopril challenge test. When considered well tolerated, antihypertensive drugs were stopped before these investigations. RESULTS: The BP-lowering was inversely related to estimated glomerular filtration rate (eGFR) in patients who stopped antihypertensive drugs prior to testing (ß: 0.46, Pâ=â0.013). There was a positive relation between SBP at baseline and the BP-lowering effect of RDN (ß:-0.55âmmHg per mmHg, Pâ<â0.001). Parameters related to the rennin-angiotensin system (aldosterone, captopril test) and the sympathetic nervous system (dipping pattern and catecholamines in urine) positively related to the BP-lowering effect of RDN. CONCLUSION: The present explorative study shows an inverse relation between the BP-lowering effect of RDN and eGFR. Second, we found relations between variables of the RAAS and SNS with the BP-lowering effect of RDN. The data complement current concepts on pathophysiology of sympathetic hyperactivity and hypertension and may give some insight in the wide range of the effect of RDN.
Subject(s)
Blood Pressure/physiology , Denervation , Hypertension/surgery , Kidney/innervation , Aged , Aldosterone/metabolism , Antihypertensive Agents/therapeutic use , Blood Pressure Monitoring, Ambulatory , Captopril/metabolism , Female , Humans , Kidney/physiopathology , Male , Middle Aged , Prospective Studies , Renin-Angiotensin System/drug effects , Sympathetic Nervous System/surgeryABSTRACT
BACKGROUND: In patients with internal carotid artery (ICA) stenosis, the circle of Willis (CoW) is the primary collateral pathway. We compared luminal diameters in the CoW before and after carotid revascularization and compared the effects of carotid endarterectomy (CEA) and stenting on these diameters. METHODS: At a single center in the International Carotid Stenting Study, 139 patients with symptomatic ICA stenosis of 50% or more were randomized to stenting (n = 81) or CEA (n = 58). The diameters of all segments of the CoW were assessed on computed tomography angiography (CTA), before and 30 days after revascularization. All evaluations were performed blinded to treatment allocation and order of CTA. RESULTS: A .10-mm increase (95% confidence interval [CI], .02-.17; 7%; P = .01) in diameter after revascularization occurred in the ipsilateral precommunicating anterior cerebral artery (A1), whereas both the ipsilateral and contralateral posterior communicating arteries decreased in diameter by .12 mm (95% CI, .04-.21; 14%; P = .01) and .08 mm (95% CI, .00-.17; 10%; P = .05), respectively. The increase in diameter of the A1 was larger after stenting (.15 mm; 95% CI, .07-.24; P = .001) than after CEA (.02 mm; 95% CI, -.11 to .15; P = .79). Only in patients treated with CEA, the diameters of the contralateral A1 and ipsilateral precommunicating posterior cerebral artery were reduced after revascularization. CONCLUSIONS: Carotid revascularization improves anterior collateralization and reduces reliance on posterior collateral pathways via the CoW. Carotid stenting and endarterectomy appear to have different early effects on collateralization.
