Thursday, June 23, 2011

The operation to 'cure' high blood pressure: how it works

LIfestyle improvements such as weight loss if necessary, exercise, stopping smoking and a low salt diet can reduce high blood pressure but many will require medication.
There are an estimated 15 million people in Britain with raised blood pressure and drugs to treat the condition are amongst the most commonly prescribed drugs.
For some people their blood pressure remains high even though they eat little salt and take medication.
In these patients the nervous system keeps sending signals from the brain to the kidneys to leave large amounts of salt in the blood which increases the volume of blood, causing a rise in pressure. The kidneys also produce hormones which cause the blood vessels to contract or dilate which also affects blood pressure.
The new procedure interferes with the signals to the kidneys by damaging the nerves carrying them.
The procedure involves passing a wire into the blood vessel in the groin and up into the main artery leading into the kidneys. From there the wire is used to make a series of tiny burns on the inside of the blood vessel which damages the nerve running along the outside of it.
The tiny burns just one millimetre across are the equivalent of snuffing a candle out between the fingers. A series of four or five burns are carried out in a spiral pattern along the inside of the artery to each kidney.
The blood vessel itself does not sustain serious damage as the blood flowing along inside it cools the burn, like running a burned finger under a tap. But the burn is deep enough to affect the nerve on the other side of the vessel.
Once the connection between the brain and kidneys is distrupted the signals to raise blood pressure should stop.
Early results show it can take between one and three months for the procedure to have an effect on blood pressure.
For some patients it will mean their blood pressure will respond to medication and for others it will mean they can reduce their dose or even stop taking them altogether.
Blood pressure is expressed with two numbers, systolic and diastolic. Systolic, the first number, reflects pressure in the arteries as the heart beats and the diastolic, the second number, is the pressure between beats.
A normal blood pressure is around 120/80 with most otherwise healthy people not suffering any ill effects up to around 130/80 and 140/90. Blood pressure between 140/90 and 160/100 is known as mildly raised and above 160/100 is definitely too high.

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