Renal circulatory effects of acetazolamide in patients with essential hypertension

Background: Reports indicate that acetazolamide (ACZ) induces the vasodilation of all vessels in animal models, as well as in small and medium kidney vessels in animal models. However, the effect of ACZ on the renal circulation of patients with essential hypertension remains unknown. In this study we examined the effects of a carbonic anhydrase inhibitor, acetazolamide (ACZ), on the renal circulation of patients with essential hypertension. Methods: We directly infused 1000 mg of ACZ into the main renal arteries of 10 patients with essential hypertension who had undergone cardiac catheterization. We then evaluated the effects of ACZ upon heart rate, renal artery blood pressure (BP), renal artery cross-sectional area, renal Doppler blood flow velocity, renal blood flow (RBF), and renal vascular resistance (RVR). Results: The infusion of ACZ was not associated with any significant changes in heart rate or in systolic or diastolic BP. However, the velocity-time integral was increased by 11.1% +/- 7.2%, from 17.6 +/- 1.8 to 20.0 +/- 3.7 cm (P=.009); RBF was increased by 39% +/- 21%, from 300 +/- 43 to 422 +/- 96 mL/min/m(2) (p =.002); and RVR was reduced by 38% +/- 20% from 24,351 +/- 2,291 to 17,651 +/- 2,731 dynes . sec . cm(-5) (p <.01). In contrast the cross-sectional area of the renal artery did not change. Conclusions: The results of the present study demonstrated that ACZ has a potent vasodilatory effect on the renal circulation of patients with essential hypertension, leading to an obvious decrease in RVR and an increase in RBF.