“It’s an amazing relief, both physically and emotionally, to be able to live my life again normally, without feeling that I’m limited all the time in what I can do.”

Cristian Jensen is describing the difference that an implant inserted in his chest – to reduce the symptoms of his debilitating angina – has had on his life.

The 64-year-old used to have five angina attacks a week, each involving a sharp, acute pain that reminded him of the heart attack he once had. Now he has an attack every week or two.

He used to have to limit the amount of exercise he did, in case strenuous activity induced an attack. Now he’s walking further and faster and no longer worries about climbing stairs.

“It’s made a huge difference to my confidence,” the packaging designer adds. “Angina is a reminder that something isn’t right with your body. It’s like a sharp pain in the middle of your chest that stops you doing what you are doing.

“The fear that the pain of an episode of angina could be a heart attack. Suddenly not having that anxiety at the back of your mind changes your life.”

Angina, a common form of heart disease, involves pain in the chest, neck, shoulders, jaw or arm.

Jensen had a long and troubled history of heart problems before consultant cardiologist Dr Ranil de Silva fitted him with the implant – a coronary sinus reducer (CSR) – at the Royal Brompton hospital, a renowned centre of specialist NHS heart and lung care in London, in 2021.

In 1990, he was diagnosed with angina at an unusually young age – at just 28 – after an angiogram showed he had blocked arteries.

Open heart surgery helped. “That fixed me, for a while at least,” he says. “I was angina-free for 17 years until I had a heart attack in 2007.” That led to him having the first of what became eight stents put in, to help his arteries stay open and his heart to keep pumping blood around his body.

But in 2015 he began taking drugs to lower the high level of bad cholesterol in his bloodstream – fatty deposits that narrow the arteries. He also started using another drug, a spray called gylceryl trinitrate (GTN), to banish the pain each of his angina attacks brought.

Jensen is one of an estimated 300,000 people in England with refractory angina. That is angina that remains problematic despite the patient having drugs, stents and heart bypass surgery.

When Jensen’s symptoms persisted, de Silva suggested he have the implant fitted. Despite the large number of people with the condition, only a handful have had what is still an experimental treatment.

The small, hourglass-shaped device is implanted near the heart using keyhole surgery through the patient’s neck. It works by narrowing a vein at the back of the heart. That helps to redirect the person’s blood flow to the parts of the heart muscle that are getting too little oxygen. Each device costs the NHS £11,400.

A new study – the largest of its kind worldwide to date – has found that the device brings about a significant fall in chest pain in 75% of people with refractory angina within six months of its implantation.

“In this respect it is potentially a gamechanger,” says de Silva, who co-led the study with his colleague Dr Kevin Cheng. It was based on observation of 491 people with refractory angina between 2014 and 2024, 474 of whom had the implant fitted at 19 hospitals in England and Scotland.

Most patients went home the day of the procedure or the day after and serious complications were rare, the study also found.

According to de Silva, it shows that the device can greatly reduce the debilitating symptoms of refractory angina that significantly compromise quality of life and the ability to undertake normal day to day activities, and can help people avoid being admitted to hospital and boost their mental wellbeing.

“Many patients report their lives being transformed and that it helps them to achieve the quality of life they wish for, that they were unable to enjoy prior to the reducer implant – they get their life back,” says de Silva.

Despite the apparent success of the implant, and that only “a tiny fraction” of the 300,000 people with refractory angina have had one fitted, it is too early to yet see CSR as a standard treatment for people with this very painful form of coronary artery disease, he says.

More trials are needed and the NHS needs to approve the funding needed to expand access, he adds.

Dr Sonya Babu-Narayan, a consultant cardiologist and the British Heart Foundation’s clinical director, said: “The findings are reassuring as they show that in routine clinical practice the device is being delivered safely and is resulting in fewer symptoms for patients.”

The device “offers hope for people living with this challenging condition”, she said.