Background: Fibromuscular dysplasia (FMD) and atherosclerotic renal artery stenosis (ARAS) are the most common causes of renovascular hypertension. So far, FMD is believed to cause hypertension via similar mechanisms as in ARAS, that is, a decrease in renal blood flow, which subsequently leads to increased renin secretion. However, given the differences in the blood pressure (BP)-lowering effect of revascularization between patients with ARAS and FMD, we questioned whether this is true.
Methods: We measured renal blood flow (133Xenon washout method) and renin secretion per kidney and their relationship to BP in a cohort of 64 patients with multifocal FMD and 110 patients with ARAS (off medication, prior to revascularization).
Results: We found that renal blood flow is significantly higher in FMD as compared with ARAS. In patients with unilateral ARAS, renin secretion was increased in the affected kidney as compared with the unaffected kidney. This lateralization in renin secretion, however, was not found in unilateral FMD. After correction for differences in baseline characteristics, we found that systemic renin levels and local renin secretion was lower in FMD as compared with ARAS. Moreover, the relationship between BP and renin secretion in FMD was inverse to that in ARAS.
Conclusion: These findings argue against the hypothesis that FMD induces hypertension via similar pathophysiological mechanism as in ARAS.
aDepartment of Internal Medicine
bCardiovascular Research Institute Maastricht (CARIM)
cDepartment of Radiology, Maastricht University Medical Center (MUMC+), Maastricht
dDepartment of Internal Medicine, Zuyderland Medical Center, Sittard, The Netherlands
Correspondence to Prof Dr Abraham A. Kroon, Department of Internal Medicine, Maastricht University Medical Center, PO Box 5800, 6202 AZ Maastricht, The Netherlands. Tel: +31 433877005; fax: +31 433875006; e-mail: email@example.com
Abbreviations: 24-hABPM, 24-h blood pressure measurement; 2K1C, two-kidney-one-clip; APRC, active plasma renin concentration; ARAS, atherosclerotic renal artery stenosis; AU, arbitrary units; CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration; eGFR, estimated glomerular filtration rate; FMD, fibromuscular dysplasia; MAP, mean arterial blood pressure; MRBF, mean renal blood flow; RSR, renin secretion rate
Received 3 October, 2016
Revised 30 November, 2016
Accepted 7 December, 2016
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