People in London are benefitting for the first time from an international clinical trial at St Bartholomew's Hospital to test an entirely novel and fully non-invasive approach to treating resistant high blood pressure - involving the use of ultrasound.
Researchers from Queen Mary University of London working with clinicians at Barts Health NHS Trust, supported by the National Institute of Health Research, are using the Surround Sound® technology, developed by Kona Medical, which uses ultrasound energy to stop kidney nerves from signalling. It is believed these signals are responsible for high blood pressure in a number of patients with difficult to control high blood pressure.
The treatment is being trialled in a study of 160 patients with resistant high blood pressure (those whose blood pressure is not controlled despite taking three or more antihypertensive drugs - believed to be 4% of adults living in London).
The blinded and randomised study, supported by the NIHR Clinical Research Network: North Thames, is being carried out at centres in London, Glasgow and Birmingham - as well as sites in Germany, the Czech Republic, Austria, New Zealand, and Australia. Half the group will receive the ultrasound treatment from the start and the other half will have a dummy treatment. Neither group will know which treatment they received but after one year, patients in the dummy group will then be offered the treatment.
The painless procedure takes place under deep sedation and takes less than one hour - with patients going home on the day they are treated. So far, results from some smaller proof of concept studies have been positive, with three quarters of patients benefiting from substantial reductions in blood pressure up to two years after the treatment.
Dr Melvin Lobo is leading the study at Queen Mary University of London and will offer the new procedure to patients at Barts Health NHS Trust in London where he is Director of the Barts Blood Pressure Clinic. Dr Lobo comments: "High blood pressure remains a serious public health issue, not just in the UK but globally, and new treatments are urgently needed. Although drug treatment works well for most patients, a number of patients do not respond well and need alternative approaches.
"The procedure we're trialling is a hugely exciting and entirely unique concept. We believe this non-invasive ultrasound treatment is a promising new approach that deserves further study in controlled clinical trials, where the safety of patients is of paramount importance."
This new treatment is a form of renal denervation, a relatively new approach to treating high blood pressure which so far has seen mixed results in clinical trials. Previous renal denervation therapies have been invasive procedures, generally involving putting a catheter into the kidney arteries and treating both arteries with radiofrequency energy to destroy kidney nerves lining the artery wall.
However, unlike previous catheter versions of renal denervation therapy, the Surround Sound® system delivers ultrasound energy to renal nerves from outside the body without any cutting, incisions or need for hospitalisation. This very precisely targeted energy 'surrounds' the artery and treats the nerves located around the vessel.
Dr Lobo continues: "Renal denervation has suffered a significant setback after a recent major study revealed disappointing results. However, this was probably due to a flawed trial design and execution. We have certainly seen a number of our patients respond very well to this treatment in the past. We believe targeting the kidney nerves will prove to be an important way of managing high blood pressure in the future for some patients. Right now, we are limiting our studies to those with severe high blood pressure who stand to benefit most by reducing their risk of stroke, heart attack and kidney failure."
Recruitment for the clinical trial, known as WAVE IV, is underway and patients may be eligible to participate in the study if they are:
- Aged between 18 - 90 years of age
- Have systolic blood pressure (top number) greater than 160 mmHg
- Currently take three or more prescription medications for high blood pressure
Any patients who answer yes to all the criteria are being encouraged to contact clinical trial team urgently so that they can be considered to take part. Potential patients can contact Margaret Swift at Barts Health NHS Trust on: 0203 4665 5763 or Margaret.Swift@bartshealth.nhs.uk. Alternatively patients can contact Kona Medical on 0800 0029205 or firstname.lastname@example.org.