Résumé
To assess the feasibility and to demonstrate the potential clinical application of intravascular doppler in the evaluation of renal blood flow in patients with hypertension and normal renal arteries.
Intravascular doppler was used to measure renal blood flow in 19 patients (34 kidneys) during arteriography to rule out renovascular hypertension. Arteriography showed no evidence of renal artery stenosis in any patient. Hemodynamic parameters, renal artery diameter, and doppler measurements were undertaken at baseline, after injection of a bolus (10 ml) of normal (0.9%) saline, and after injection of isosorbide dinitrate (1 mg diluted in 10 ml normal saline).
Repeated measurements of renal blood flow confirmed the reproducibility of the technique. Basal blood flow was similar in both right and left kidneys; injection of vehicle solution (10 ml normal saline) had no effect on doppler parameters. Injection of isosorbide dinitrate resulted in a significant increase in renal blood flow velocity reflecting an increase in renal blood flow; this demonstrates the existence of a renal flow reserve. The degree of increase in renal blood flow varied significantly between kidneys.
Intravascular doppler is a safe, effective, and reproducible technique for measurement of renal blood flow. It allows evaluation of variations in renal blood flow in response to diverse vasoactive drugs or other vasomotor stimuli. The present study demonstrated the heterogenous response of renal blood flow in response to vasodilator stimuli.