Hypertension gets Pressure

13. October 2008

Bye, bye hypertension pills? If the Medical University Hanover gets its way, the concert of anti-hypertensive therapies will at least turn a bit more polyphonic. Experts there are testing now the first pacemaker against too high blood pressure. A large vaccination study runs parallel to it.

Ever since the introduction of the inhibitors of the renin-angiotensin systems, the hypertensiologists’ community sort of ran out of gas in regard to therapy innovations – apart from the direct renin inhibition discussed for decades now with a status yet utterly unclear within the therapeutic canon. But there seems to be another innovation boost just about to happen: Whilst the pharmacotherapy with drugs is exhausted, the manufacturers of medical devices and of vaccines want to ensure their slice of pie called hypertension therapy. In Germany alone we are talking about more than 16 million people. The hypertension league estimates the number of affected people at about 1 billion worldwide. Every fourth at most receives an adequate therapy.

So as if: Pacemaker massages the carotid sinus

A new pacemaker might bring the change which lowers the blood pressure by stimulating the blood pressure sensors in the carotids – a wonderful way to fool the brain: it thinks that the blood pressure is way too high and starts counter regulation mechanisms reducing the pressure. Thus the pacemaker is an a bit more gentle variation of the very k. o. grip on the carotid artery students learn in their physiology course, if not before in self-defence class.

For the first time in Germany, eight patients at the Medizinische Hochschule Hannover (medical university of Hanover) received such a pacemaker. “We implant the device underneath the collar bone and lead the activation wires to the two carotids”, Dr. Andreas Pichlmaier of the heart-/thorax and vascular surgery hospital describes the procedure. Different from a regular pacemaker implantation this surgery is rather complex: two to four hours are necessary – according to Pichlmaier – because the position of the electrodes has to be tested intraoperatively. The final setup is done from outside by radio transmission. According to international data the pacemakers can lower the blood pressure of some patients for about 100mH. A European study with 35 patients showed a result of an average 30mH. “We were able to lower the blood pressure of a female patient who did not stomach therapy with five different drugs for about 60 to 70mmHg permanently”, emphasizes MHH physicians Dr. Jan Menne. Admittedly the device is not approved yet. Currently the manufacturer, the US company CVRx, plans a certification study with 300 patients for the Rheos Baroflex Hypertension Therapy System. Here the major interest is the permanent therapy. After all it might be feasible that the body adapts the simulation quickly because it notices that it does not have anything to do with reality.

Angiotensin inhibition rephrased

Should the pacemaker turn out to be non-practicable, a second great hope is ready-steady-go for some time now: a vaccination against hypertension. AngQb is the admittedly a bit fanciless name of the vaccine developed by the Swiss biotech manufacturer Cytos. The vaccines belong to a vaccine class called “immunodrugs”. For this particular class Cytos recently entered into a cooperation agreement with the Pfizer group. The injected agent of AngQb is the angiotensin II, raising the blood pressure, and assembled in various copies on the surface of a virus-like particle. The body creates specific antibodies against the injected variation of angiotensin II which also bind to body own angiotensin II, neutralize it and accordingly lower the blood pressure. Now the vaccine is getting tested on 80 patients all over Germany and again, MHH is in charge and will see after 20 patients.

Many questions are still open

Professor Hermann Haller, head of the MHH-clinic for nephrologyie and hypertensiology, sets great hope on the vaccination: “It is our target to replace drugs with this vaccination. We would have a completely new type of treatment. Patients would not have to take the pills every day. Instead they would have protection for a longer time frame with only one shot”. That would be the ideal case which nonetheless does not necessarily has to happen. Professor Manfred Schubert-Zsilavecz, pharmaceutical chemist at the Frankfurt University, warns against too much euphoria: “The data is rather tenuous. Many questions are unexplained such as what is the optimum dosage and what are the consequences for the salt- and water metabolism. And also how long the vaccination lasts we don’t know yet either”, comments the expert during an interview with the DocCheck newsletter.

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