Hundreds of thousands more people should be offered drugs that lower blood pressure, according to new guidelines for doctors from the NHS medicines watchdog intended to tackle heart attack and stroke deaths.

As many as 720,000 extra adults could be prescribed drugs such as valsartan and beta blockers under the revised prescribing guidelines proposed by the National Institute for Health and Care Excellence (Nice).

Under existing recommendations, GPs are advised to recommend medication to patients with slightly raised blood pressure and a more than 20 per cent chance of developing cardiovascular disease in the next 10 years.

This threshold has now been lowered to anyone with a 10 per cent chance in the latest draft guidelines – the biggest change since 2011.

Nice says that as many as half of these patients may already be on blood pressure drugs, but GP leaders warned there was a significant risk of over diagnosis and unintended harms from medication side effects from the changes.

Roughly a quarter of adults in the UK have high blood pressure and experts said it was by far the biggest preventable cause of heart attacks and strokes.

Under the skin – best of the British Heart Foundation 2018 image prize Show all 10 1 /10 Under the skin – best of the British Heart Foundation 2018 image prize Under the skin – best of the British Heart Foundation 2018 image prize Subarachnoid vessels The runner-up image came from Matt MacGregor Sharp, a PhD student at the University of Southampton. The super-high resolution image shows a normal artery at the surface of a rat’s brain and was taken with a powerful scanning electron microscope. These ‘subarachnoid vessels’ supply blood to the brain and also act like a drain to remove toxic waste products. Matt Macgregor’s team are trying to show that failure to remove waste by these vessels is one of the underlying causes of vascular dementia. The researchers took the image using a technique called ‘freeze fracture’, where tissue or cell samples are frozen and then split apart to reveal the hidden layers within the sample so they can be studied in extreme detail. Sitting above the brown brain tissue, the artery appears blue, and its surrounding layer, the pia mater, is shown in purple. Matt MacGregor Sharp, University of Southampton, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Explosive beginnings Winner: Endothelial cells line all blood vessels in the body, forming a barrier between the circulating blood and the vessel wall. They also help to protect blood vessels from damage and release important chemical messengers which help to control blood pressure. The winning researcher, Courtney Williams, is a Masters student and PhD candidate at Leeds University. Her lab are developing new ways to map the growth of new blood vessels within their surrounding landscape in 3D. Understanding the complex secrets of blood vessel formation could be harnessed to boost the regrowth of damaged blood vessels after a heart attack, and halt blood vessel growth when it’s counterproductive. Courtney Williams, Leeds University, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize A snapshot of platelet production - Reflections of Research Supporters’ Favourite This image from Abdullah Obaid Khan, a PhD student at the University of Birmingham, won the supporters’ favourite. What look like precious jewels are actually platelets forming within the bone marrow. Platelets are the smallest of our circulating blood cells with a hugely important role in preventing bleeding. However, they also play a role in the formation of clots, which can lead to heart attacks and strokes. Abdullah Obaid Khan and his team are studying rare bleeding disorders. Abdullah Obaid Khan, University of Birmingham, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Cardiac collagen web - Shortlist This colourful image shows the web-like, network of the smallest blood vessels in the heart – the microvessels. Magenta marks the outer collagen layer of the vessels; while orange marks their inner lining and blue the cell nuclei. Dr Neil Dufton, Imperial College London Dr Neil Dufton, Imperial College London, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Heart to Heart - Shortlist This piece shows four ventricles (from a mouse) arranged into the shape of the hearts four normal chambers. The researchers have used fluorescent markers to recognise certain proteins and created the image using of hundreds of images assembled together. Dr Elisa Avolio and Dr Zexu Dang, University of Bristol Dr Elisa Avolio and Dr Zexu Dang, University of Bristol, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Loving artery - Shortlist This image shows a cross section of an artery and the different layers which make up the artery wall. Affiliate Professor Silvia Lacchini, University of Glasgow Silvia Lacchini, University of Glasgow, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Oxidative inkblot - Shortlist This colour explosion shows one of the culprits in cardiovascular disease – an enzyme called NADPH oxidase. The enzyme is considered ‘Janus faced’ because it is important in health, as well as disease. This picture shows the active enzyme in patients who have high blood pressure. Dr Livia de Lucca Camargo, University of Glasgow Dr Livia de Lucca Camargo, University of Glasgow, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Neon skeleton - Shortlist This image shows the developing blood vessel system of a two day old zebrafish embryo. The researchers used gene enhancers (the on-off switches of genes) to switch on fluorescent markers in different types of endothelial cells – the important cells which line all blood vessels. All blood vessels switch on the red marker, while the veins also switch on the green marker, resulting in yellow veins and red arteries. Dr Svanhild Nornes, University of Oxford Dr Svanhild Nornes, University of Oxford, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Calcium reef - Shortlist This image shows calcium in blood vessel cells from people who have high blood pressure and resembles Australia’s Great Barrier Reef. Dr Rheure Alves-Lopes, University of Glasgow Dr Rheure Alves-Lopes, University of Glasgow, British Heart Foundation - Reflections of Research Under the skin – best of the British Heart Foundation 2018 image prize Budding blood vessels - Shortlist This image shows the growing blood vessels in the mouse retina. In red you can see all the blood vessels and in yellow/green you can see the blood vessels that are actively growing (a process called sprouting). PhD candidate Kira Chouliaras, University of Oxford Kira Chouliaras, University of Oxford, British Heart Foundation - Reflections of Research

“Many people with high blood pressure don’t actually know they have it because it rarely causes any noticeable symptoms,” said Dr Anthony Wierzbicki, chair of the Nice panel and a heart disease specialist at Guy’s and St Thomas’ hospital.

“However, it is by far the biggest preventable cause of death and disability in the UK through strokes, heart attacks and heart failure.”

While promoting lifestyle changes – such as cutting down on salt, losing weight and keeping active – Dr Wierzbicki said the new guidelines were a shift to earlier intervention to slow age-related blood pressure increases.

But the Royal College of General Practitioners (RCGP) said a decision to confirm the draft guidelines should not be taken lightly.

“Many GPs do also have concerns about over diagnosis and the unintended harms of prescribing medication to groups of patients when the benefits may be limited,” said Professor Helen Stokes-Lampard, chair of the RCGP.

“Lowering the threshold for making a diagnosis of hypertension, or high blood pressure – a condition that already affects a very large number of patients in the UK – is likely to affect thousands, if not millions of patients so this decision must not be taken lightly and must be evidence-based.”

Blood pressure drugs including ACE inhibitors and beta blockers cost the NHS as little as 10p a day to prescribe.

However, cardiovascular disease related to high blood pressure hypertension is estimated to cost £2bn a year, and take up more than one in 10 GP appointments.

Higher blood pressure is a sign the heart is having to work harder to pump blood around the body as a result of arteries becoming narrows and stiff. This pressure can increase the chance of plaque breaking off from blood vessels and causing a clot.

The current guidelines apply to stage one raised blood pressure, the lowest category, which is not linked to a single specific cause but can be a result of obesity, too much salt, or genetic factors.

Around 450,000 men and 270,000 women would be eligible for blood pressure drugs under the new guidelines.

Support free-thinking journalism and attend Independent events

However, other experts said that the guidelines should have gone further, as has been the case in the US and Europe.

“The new draft guidance from Nice is surprisingly conservative,” said Professor Stephen MacMahon from the University of Oxford, warning that the target blood pressure was only slightly below the level for starting treatment.

“This will almost certainly result in large numbers of patients not achieving the full potential benefits of treatment as a consequence of inadequate reduction in blood pressure,” he said.

“Much lower blood pressure targets are required and multiple drugs need to be used right from the start if patients are to achieve the largest reduction in the risks of stroke and heart attack.”

In 2015, it was reported that in England, high blood pressure affected more than one in four adults (31 per cent of men; 26 per cent of women) – around 13.5 million people – and contributed to 75,000 deaths.