title: Nitric oxide dependence of renal blood flow in patients with renal artery stenosis.
abstract: In ischemia, nitric oxide (NO) production is increased, possibly to preserve flow. The role of NO was investigated in hypertensive patients with or without renal artery stenosis (RAS). Fifty-five hypertensive patients scheduled to undergo diagnostic renal angiography underwent mean renal blood flow (MRBF) measurements before and after an intrarenal injection of the NO synthase blocker N(g)-monomethyl-L-arginine (L-NMMA) at 0.03 microg/kg, before angiography. A dose-response study indicated that this dose of L-NMMA significantly blocked NO synthesis. MRBF was measured at baseline and 1, 5, 10, and 20 min after L-NMMA treatment. On the basis of the angiographic results, patients were divided into three diagnostic categories, i.e., essential hypertension (n = 26), unilateral RAS (n = 16), or bilateral RAS (n = 8). In essential hypertension, MRBF was decreased by 18 +/- 4% at 20 min. In unilateral RAS, L-NMMA did not affect MRBF in the stenotic kidney but reduced MRBF in the nonstenotic kidney by 40 +/- 9% at 20 min. In bilateral RAS, L-NMMA reduced flow by 32 +/- 14% at 20 min. In the nonstenotic kidney in unilateral RAS, a positive correlation was observed between the effect of NO blockade on MRBF and arterial renin levels (P = 0.009). In the stenotic kidney, in contrast, this correlation was inverse (P = 0.007). In conclusion, MRBF depends on NO in hypertensive patients, except in the stenotic kidney in unilateral RAS. In the nonstenotic kidney in unilateral RAS, NO bioavailability is increased. It is suggested that a compensatory mechanism, regulated by NO and possibly angiotensin II, may preserve renal function.
authors.affiliation: Department of Internal Medicine, University Hospital Maastricht and Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands.
authors.forename: Thomas K A
authors.initials: TKA
authors.lastname: Wierema
authors.affiliation: Department of Internal Medicine, University Hospital Maastricht and Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands.
authors.forename: Alphons J H M
authors.initials: AJHM
authors.lastname: Houben
authors.affiliation: Department of Internal Medicine, University Hospital Maastricht and Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands.
authors.forename: Abraham A
authors.initials: AA
authors.lastname: Kroon
authors.affiliation: Department of Radiology, University Hospital Maastricht and Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands.
authors.forename: Derk
authors.initials: D
authors.lastname: Koster
authors.affiliation: Department of Internal Medicine, University Hospital Maastricht and Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands.
authors.forename: Kim VAN DER
authors.initials: KV
authors.lastname: Zander
authors.affiliation: Department of Radiology, University Hospital Maastricht and Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands.
authors.forename: Jos M A VAN
authors.initials: JMAV
authors.lastname: Engelshoven
authors.affiliation: Department of Internal Medicine, University Hospital Maastricht and Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands.
authors.forename: Peter W DE
authors.initials: PW
authors.lastname: Leeuw
mesh_terms: D000792:Angiography; D000804:Angiotensin II / Q000097:blood; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D012016:Reference Values; D012078:Renal Artery Obstruction / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012079:Renal Circulation / Q000502:physiology*; D012083:Renin / Q000097:blood; D012720:Severity of Illness Index; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D000804:Angiotensin II; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D012083:Renin