Electronic implant could treat high blood pressure

High blood pressure is the greatest global health risk after smoking and alcohol consumption, affecting almost one in three U.S. adults. The condition is typically treated with drugs, which may have unwanted side effects or even be ineffective among a significant percentage of the patient population. An implantable device equipped with nerve-stimulating electrodes developed by researchers at the University of Freiburg in Germany could one day provide patients with a drug-free way to lower high blood pressure.

The 20-mm-long (0.79 in.) cuff wraps around the vagal nerve in the neck, which "exchanges critical physiological information between the brain and other major organs, including the heart," writes Susan Young Rojahn in MIT Technology Review. Fitted with 24 electrodes, the device identifies the electrode that is closest to the nerve fibers that transmit the blood pressure signal to the brain. The electrode then stimulates a change in blood pressure without affecting any of the other fibers.

"Our cuff consists primarily of plastic—more precisely polyimide," Dennis Plachta from the university's Laboratory of Biomedical Microtechnology, Department of Microsystems Engineering, told PlasticsToday. "This material is not really new to implants and neuro-electronic interfaces, but it is advancing fast because of its key features, he explains.

"Thin-film technology allows superior density of active components due to highly miniaturized structures and it is flexible, reducing stress to the tissue," says Plachta, adding that his department has a long history developing designs and processes involving polyimide electrodes.

In animal tests conducted by Plachta and fellow researcher Thomas Stieglitz, also from the department, the device achieved a 30% reduction in mean blood pressure without causing any noticeable side effects. The findings have been published in the Journal of Neural Engineering.

Neurosurgeons Dr. Mortimer Gierthmühlen and Prof. Dr. Josef Zentner from the university medical center participated in the research.

Ultimately, the device could be used in lieu of medication, which is ineffective in treating approximately 30% of patients and can cause side effects that have a negative impact on patient compliance. It can also be used in tandem with pharmaceuticals, say the researchers.

Don't plan to stop taking your Norvasc/low-dose-Aspirin cocktail any time soon, though. The research is in the early stages and, assuming that the research moves forward without encountering any speed bumps, the device won't be available for at least 10 years.