title: Ultrasound evaluation of valsartan therapy for renal cortical perfusion.
abstract: An increase in renal blood flow with a concomitant decrease in filtration fraction at the onset of angiotensin II receptor blocker treatment has been shown to predict a long-term renoprotective effect. However, no studies are available regarding angiotensin receptor blocker-induced changes in renal cortical perfusion observed in the clinical setting. We have recently developed a convenient method of evaluating human renal cortical blood flow with contrast-enhanced harmonic ultrasonography. The goal of this study was to use this method to examine the effect of valsartan, an angiotensin II receptor blocker, on renal cortical perfusion. We performed intermittent second harmonic imaging with venous infusion of a microbubble contrast agent in 7 healthy volunteers. Contrast-enhanced harmonic ultrasonography performed after oral administration of valsartan (80mg) showed a significant increase in microbubble velocity, which correlated well with the increase in total renal blood flow determined by p-aminohippurate clearance (r=0.950, p < 0.001). Although fractional vascular volume was not significantly increased, alterations in renal cortical blood flow calculated by the product of microbubble velocity and fractional volume were also correlated with the change in total renal blood flow (r=0.756, p < 0.05). These results indicate that valsartan increases the renal cortical blood flow in normal kidneys, mainly by increasing blood flow velocity. Contrast-enhanced harmonic ultrasonography is a promising technique for evaluating the precise effect on renal cortical perfusion and optimal dose of valsartan in diseased kidneys.
authors.affiliation: Department of Medicine II, Kansai Medical University, Osaka, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Kishimoto
authors.forename: Yasukiyo
authors.initials: Y
authors.lastname: Mori
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishiue
authors.forename: Atsuko
authors.initials: A
authors.lastname: Nose
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Kijima
authors.forename: Toshiko
authors.initials: T
authors.lastname: Tokoro
authors.forename: Hideki
authors.initials: H
authors.lastname: Yamahara
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Okigaki
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kosaki
authors.forename: Toshiji
authors.initials: T
authors.lastname: Iwasaka
mesh_terms: D000328:Adult; D000388:Air; D057911:Angiotensin Receptor Antagonists; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007672:Kidney Cortex / Q000098:blood supply* / Q000000981:diagnostic imaging*; D008297:Male; D008863:Microspheres; D012079:Renal Circulation / Q000187:drug effects*; D013777:Tetrazoles / Q000494:pharmacology*; D014463:Ultrasonography; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology*; D000068756:Valsartan
chemical_list: D057911:Angiotensin Receptor Antagonists; D013777:Tetrazoles; D000068756:Valsartan; D014633:Valine