Ultrasound energy used to treat high blood pressure

A minimally invasive procedure that targets the nerves near the kidney has been found to significantly reduce blood pressure in hypertension patients, according to a global multicentre clinical trial featuring participants in the UK, the US, France, Germany, the Netherlands and Belgium.

The trial tested a one-hour procedure called ‘renal denervation’, which uses ultrasound energy to disrupt the nerves between the kidneys and the brain that carry signals for controlling blood pressure. The results, published in The Lancet and presented at the American College of Cardiology’s 2021 virtual meeting, suggest that the procedure could offer hope to patients with high blood pressure who do not respond to recommended treatments (resistant hypertension) and are at greatly increased risk of cardiovascular diseases, including stroke and heart attack.

“Resistant hypertension patients often suffer from organ damage, including damage to the heart, eyes and kidneys, have poor quality of life and are at a higher risk of cardiovascular events and death,” said Dr Manish Saxena from Queen Mary University of London and Barts Health NHS Trust, who ran the UK trial site at St Bartholomew’s Hospital.

“Many high-risk patients have to manage multiple prescription medications, which can be difficult to adhere to and poses a significant challenge to our healthcare system and resources.

“Finding other ways to reduce blood pressure in these difficult-to-treat patients, such as renal denervation, will lower their cardiovascular risk, reduce their medication load, improve their quality of life and ultimately lead to cost savings for the NHS.”

The study investigated 136 patients who were randomised to receive either renal denervation or a ‘sham procedure’ — the surgical equivalent of a placebo. The trial showed that renal denervation led to a significant and safe blood pressure-lowering effect after two months in patients who were on at least three different blood pressure lowering medications. It was found to reduce blood pressure by 8 mmHg, which was a 4.5 mmHg greater drop when compared with patients who had the sham procedure.

One of the study participants was 49-year-old Raenard Gonzalez, who has been on blood pressure tablets for around 19 years — and for the last nine years has had to take five different tablets every day.

“It’s been so difficult to manage, and the dosage was constantly increased by my consultant,” Gonzalez said. “I felt lethargic and it was hard to maintain a healthy weight, as I just had to keep eating to combat the tiredness and keep myself awake.

“Since the procedure, I’ve managed to control my weight, and have so much more energy and motivation. My blood pressure used to stay high after any physical activity, but now it doesn’t matter how much I exert myself — my blood pressure always goes back down.

“All the medications that I took before the trial have been scrapped and I’m now just taking one triple combination pill. I’m really happy that this treatment may soon be available to other people.”

“This is probably one of the most important studies in the field of hypertension emerging in the pandemic era,” said UK Principal Investigator Professor Melvin Lobo, from Queen Mary University of London and Barts Health NHS Trust. “It is conceivable that renal denervation could become a treatment option for patients with hypertension in the very near future, and the National Institute for Health and Care Excellence (NICE) will be re-evaluating the technology based upon the recent datasets in the coming months.”

Image caption: The renal denervation system.

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