Novel baroreceptor activation therapy

Despite the availability of many antihypertensive drugs, there is still a sizeable portion of hypertensive patients in whom blood pressure does not fall or is reduced insufficiently during treatment. Treatment resistance, therefore, is one of the challenges of contemporary hypertension research. Since the autonomic system plays a major role in the pathogenesis of hypertension, in particular when this is resistant to drug treatment, investigators have searched for methods to lower sympathetic outflow in the body. One of the methods by which this can be achieved is to activate the baroreceptor reflex by means of an electrical device. Presently, clinical trials are being conducted to assess the clinical usefulness of such a device. So far, the only device that has been tested clinically is the rheostm baroreflex hypertension therapy system and its successor, the barostim neo tm device. These are open-loop systems with electrodes that are attached surgically to the carotid artery at close proximity to the bifurcation. While the rheos device still worked through bilateral stimulation, the other one has been designed for unilateral implantation and stimulation. A feasibility study has shown that baroreceptor activation therapy lowers blood pressure and heart rate significantly in a voltage-dependent way. A randomized trial which compared activation immediately after implantation of the electrodes with that 6 months after implantation confirmed the efficacy of the device although the short-term effects were a bit disappointing. Long-term results are very promising and the side effects are minimal. The sustained reduction in pressure is associated with regression of left ventricular hypertrophy. Renal function remains preserved.keywordsbaroreceptorsympathetic nervous systemtreatment resistancetarget organ damagerheosbarostim neo