A new analysis of the data on severe aortic stenosis reveals that the potential demand from undiagnosed patients exceeds NHS capacity to screen or treat the disease

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The burden of severe aortic stenosis in the UK far exceeds the capacity of the NHS to screen or treat the disease, according to a study published in Open Heart. The study is the first to specifically estimate the treatable burden of severe aortic stenosis in the UK population.

Professor Geoffrey Strange, director of the National Echo Database Australia and lead author on the study, told Medscape UK: ‘There is a huge discordance between the number of patients being diagnosed and those that the evidence suggests are out there in the community.

‘We’ve tried to uncover the true treatable burden of severe symptomatic aortic stenosis for the UK population. And in doing so, we’ve found a large number of people living with symptomatic, severe aortic stenosis who would benefit from intervention.

‘There seems little doubt, therefore, that there is a significant shortfall between interventions undertaken for severe aortic stenosis and our estimates of potential demand.’

The multi-centre study from Australia and the UK, including the Universities of Glasgow, Southampton, and Manchester, estimates that close to 200,000 people aged 55 years and over in the UK are likely to be living with severe, symptomatic aortic stenosis, of whom around two-thirds would potentially benefit from surgical aortic valve replacement (SAVR) or transcatheter aortic valve implantation (TAVI). This figure is far greater than the current capacity of the NHS to provide these services.

Across the NHS, demand for TAVI already outstrips availability. Recent data have shown that the number of TAVI procedures performed in the UK per head of population is significantly lower than in almost any other European nation. A report from the UK National Institute of Cardiovascular Outcomes Research has further warned of the detrimental impact of the COVID-19 pandemic on provision of SAVR and TAVI.

In addition to highlighting the number of people currently living with undiagnosed disease, the new analysis predicts that around 28,000 people will newly develop severe aortic stenosis each year. The study estimates that 59.3% of people with severe aortic stenosis will die within 5 years without proactive management, making it a priority to find and treat these people early.

‘If we don’t find these patients now, in the next 5 years approximately 50% of those individuals will be dead,’ explained Professor Strange. ‘We have to do something to find these patients.’

Modelling the burden of disease

Aortic stenosis is the most common valvular heart disease requiring clinical intervention. Its development is typically gradual and it can go undetected without active screening, with symptoms appearing only when disease is already advanced. There is high mortality associated with untreated severe aortic stenosis, especially once symptoms develop.

Despite this, few studies have examined the prevalence of undiagnosed aortic stenosis in the UK. Definitive screening using echocardiography is difficult to implement in study populations, so the disease burden is usually described from the perspective of people already diagnosed.

To obtain more precise estimates for the prevalence of both diagnosed and undiagnosed disease, Professor Strange and his colleagues combined existing modelling data from large European and North American meta-analyses with real-world data from the National Echo Database of Australia, the largest echocardiography database in the world.

Applying these data to UK population statistics, the authors were able to derive age-stratified estimates for the prevalence of severe aortic stenosis in the UK in 2019: 0.4% in 55–59 year olds; 0.5% in 60–64 year olds; 0.7% in 65–69 year olds; 1.2% in 70–74 year olds; and 3.5% in over 75s (the index prevalence estimate).

Overall estimated point prevalence was 1.48%, which equates to around 300,000 people living with severe aortic stenosis in the UK at any one time.

The authors further stratified severe disease into symptomatic and asymptomatic, focusing on the almost 200,000 severe, symptomatic cases which are most likely to be considered for treatment. Of these, around 168,000 people would benefit from SAVR or TAVI based on current guidelines.

‘We used the most conservative estimates for this analysis,’ explained Professor Strange, ‘and these data support a tsunami of patients that need to be found’. 

The NHS long term plan

The 2019 NHS long term plan highlighted the need for better detection of heart valve disease and access to specialist care. There is a known high mortality rate for patients on TAVI waiting lists and the long term plan commits the NHS to providing better access to echocardiography in primary care and earlier detection of valve disease and heart failure.

‘Critically, such an indicative burden is far greater than the current capacity within the NHS to screen, detect, triage, and treat such cases,’ the team said.

Furthermore, valvular cases in the UK are predicted to more than double by 2046. Based on the new prevalence and survival estimates and other data, the team further estimated the annual number of new cases of severe aortic stenosis among those aged 60 years and over to be approaching 29,000.

‘Applying the same surgical risk profile as before, around 20,000 people a year would potentially benefit from SAVR or TAVI,’ they said

This is around double the current number of procedures undertaken.

Professor Huon Gray, emeritus national clinical director for heart disease for NHS England and one of the study co-authors, told Medscape UK: ‘The challenges in managing valvular heart disease are well known: lack of awareness, poor prognosis if untreated, and inequalities in access to echocardiography and specialist care. This paper highlights the shortfall in the way that people with aortic stenosis are currently detected and treated in the UK.

‘Understanding the scale of the challenge should help the NHS plan the expansion of services needed to detect and care for the ever increasing number of people with this life-threatening condition.’ 

Commenting on the study, Professor Sir Nilesh Samani, medical director at the British Heart Foundation, said: ‘This study estimates the burden of aortic stenosis in the UK currently. As the population ages, the number of people in the UK living with aortic stenosis is expected to rise further, which will inevitably put health services under even more pressure. Aortic stenosis significantly increases the risk of heart failure, so it is vital that patients have access to the best treatment when required to avoid their condition worsening.

‘We can only continue to identify the most effective treatments through research. The British Heart Foundation is funding research into better treatments for aortic stenosis, and, if successful, this could help to reduce the risk of debilitating and potentially deadly heart failure for increasing numbers of people.’

This article was originally published on Medscape, part of the Medscape Professional Network.

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