Functional effects of renal artery stent placement on treated and contralateral kidneys.
BACKGROUND
This study examined the effects of stent placement for renal artery stenosis on the function of treated and contralateral kidneys.


METHODS
Eighteen patients who underwent stent placement for unilateral renal artery stenosis presenting with hypertension and/or renal failure were studied before angiography and stent placement and at their one-year follow-up. Renal vein blood samples were taken at both sides, at each side simultaneously with a sample from the aorta, to measure the plasma renin concentration and the concentrations of 131I-hippuran and 125I-thalamate during constant systemic infusion of these radiochemicals. This allowed an assessment of the single-kidney contributions to the total renin secretion, effective renal plasma flow (131I-hippuran clearance) and glomerular filtration rate (125I-thalamate clearance).


RESULTS
At the one-year follow-up, the vein-to-artery renin ratio at the treated side had decreased to normal, from 1.65 +/- 0.131 to 1.23 +/- 0.076 (mean +/- SEM; P = 0.011), indicating an improved renal blood flow. Contralaterally it rose from 1.09 +/- 0.042 to 1.17 +/- 0.029 (P = 0.055) at follow-up. The extraction ratio of 131I-hippuran improved at the treated side (0.48 +/- 0.049 to 0.62 +/- 0.034; P = 0.003) and contralaterally (0.67 +/- 0.033 to 0.73 +/- 0.026; P = 0.043). The extraction ratio of 125I-thalamate, which equals filtration fraction, improved at both sides (0.12 +/- 0.014 to 0.17 +/- 0.012 at the treated side, P = 0.001; 0.18 +/- 0.013 to 0.22 +/- 0.011 contralaterally, P = 0.002). Two-kidney effective renal blood flow and glomerular filtration rate remained unchanged.


CONCLUSIONS
Renal artery stenting was capable of causing improvement of glomerular filtration rate of the treated kidney, although the overall glomerular filtration rate did not change.
Leertouwer
Trude C
TC
Department of Radiology, Erasmus University Medical Center, Rotterdam, The Netherlands. pattynama@rond.azr.nl
Derkx
Frans H M
FH
Pattynama
Peter M T
PM
Deinum
Jaap
J
van Dijk
Lukas C
LC
Schalekamp
Maarten A D H
MA
D000368:Aged; D017130:Angioplasty; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006801:Humans; D007457:Iodine Radioisotopes; D007465:Iodohippuric Acid; D007483:Iothalamic Acid; D007668:Kidney / Q000098:blood supply* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D012077:Renal Artery / Q000601:surgery*; D012078:Renal Artery Obstruction / Q000175:diagnosis* / Q000601:surgery*; D012079:Renal Circulation; D012083:Renin / Q000097:blood; D015607:Stents; D016896:Treatment Outcome
D007457:Iodine Radioisotopes; D007465:Iodohippuric Acid; D007483:Iothalamic Acid; D012083:Renin