Chronic lowering of blood pressure by carotid baroreflex activation: mechanisms and potential for hypertension therapy

Abstract

Recent technical advances have renewed interest in device-based therapy for the treatment of drug-resistant hypertension. Findings from recent clinical trials regarding the efficacy of electric stimulation of the carotid sinus for the treatment of resistant hypertension are reviewed here. The main goal of this article, however, is to summarize the preclinical studies that have provided insight into the mechanisms that account for the chronic blood pressure-lowering effects of carotid baroreflex activation. Some of the mechanisms identified were predictable and confirmed by experimentation. Others have been surprising and controversial, and resolution will require further investigation. Although feasibility studies have been promising, firm conclusions regarding the value of this device-based therapy for the treatment of resistant hypertension awaits the results of current multicenter trials.

Figure

Mean arterial pressure and sodium excretory responses to prolonged baroreflex activation in dogs before (control) and after induction of ANG II hypertension. Responses to baroreflex activation in an additional group of dogs with obesity hypertension are also illustrated. Values are mean ±SEM (n=6). P<0.05 vs control. Values for MAP before baroreflex activation: control=93±1 mmHg, ANG II hypertension=129±3 mmHg, and obese hypertension=110±3 mmHg. (From Lohmeier et al).