The effect of captopril on renal blood flow in renal artery stenosis assessed by positron tomography with rubidium-82.
The sequence and magnitude of acute changes in renal blood flow following administration of captopril were determined in a canine model of acute unilateral renal artery stenosis using rubidium-82 and positron emission tomography. Data were recorded in each of nine dogs under three conditions: 1) during a baseline control interval, 2) during renal artery stenosis, and 3) during stenosis with intravenous injection of captopril (1.2 mg/kg). Mean arterial blood pressure was 108 +/- 12 mm Hg at control, increased significantly to 125 +/- 13 mm Hg (p less than 0.01) during stenosis, and decreased to 98 +/- 13 mm/Hg (p less than 0.01) after captopril infusion. Mean renal blood flow was calculated using a steady state single compartment model from the images produced by positron emission tomography. The estimated flow to the affected kidney was 3.37 +/- 1.48 ml/min/g at control, 0.86 +/- 0.62 ml/min/g during stenosis (p less than 0.01), and 0.64 +/- 0.57 ml/min/g after captopril administration (p = NS compared with precaptopril value). The estimated flow to the contralateral kidney was minimally reduced from a baseline of 3.84 +/- 0.95 to 3.24 +/- 1.13 ml/min/g (p = NS) during stenosis and increased after captopril infusion (4.08 +/- 0.94 ml/min/g; p = 0.01). These data suggest that repetitive imaging with positron emission tomography can be used to delineate acute changes in renal perfusion following captopril administration.
Tamaki
N
N
Department of Radiology, Massachusetts General Hospital, Boston 02114.
Alpert
N M
NM
Rabito
C A
CA
Barlai-Kovach
M
M
Correia
J A
JA
Strauss
H W
HW
D000818:Animals; D002216:Captopril / Q000494:pharmacology*; D004285:Dogs; D007668:Kidney / Q000000981:diagnostic imaging*; D012078:Renal Artery Obstruction / Q000000981:diagnostic imaging* / Q000503:physiopathology; D012079:Renal Circulation / Q000187:drug effects*; D012084:Renin-Angiotensin System / Q000187:drug effects*; D012414:Rubidium Radioisotopes; D014055:Tomography, Emission-Computed
D012414:Rubidium Radioisotopes; D002216:Captopril