Evidence
Alert

Surgical replacement of aortic valves offers good long-term survival

People undergoing surgery to replace a narrowed aortic heart valve (aortic stenosis) have only slightly lower life expectancy than people without the condition. Surgery was also associated with a low rate of stroke.

This review gathered data from 93 observational studies that followed long term outcomes for people with severe aortic stenosis who had the valve replaced with a biological or tissue (bioprosthetic) valve.

Following surgery, survival ranged from 16 years on average for people aged 65 or less, to six or seven years for those over 75. Fewer than one in 100 developed a stroke each year.

Ten years after surgery most people (94%) still had a good functioning valve. By 20 years the rate of valve deterioration had risen to 48%.

Bioprosthetic valves appear safe and are linked to average lifespan for this population, but there may be a need for monitoring and possible replacement after the first ten years.

 

Why was this study needed?

The heart pumps blood through the aortic valve around the body. In many people the valve becomes narrower and less supple with age and this can put a strain on the heart as it works harder to pump blood. Symptoms include tiredness, feeling out of breath, chest pains, dizziness and fainting. Eventually aortic stenosis can lead to heart failure.

People with severe symptoms can be helped by replacing the valve with a mechanical valve, or a bioprosthetic valve. This systematic review explored long-term outcomes from surgical replacement with a bioprosthetic aortic valve, including mortality and valve deterioration. Transcatheter aortic valve replacement, a more recent minimally invasive technique which may be more suitable for some people, was not covered by this review.

 

What did this study do?

This systematic review identified 93 observational studies including a total 53,884 adults undergoing bioprosthetic aortic valve replacement for severe aortic stenosis. Only studies published after 2006 were included to ensure relevance to current technologies. Patients were enrolled between 1977 and 2013. Average patient age was 53 to 92 years.

The researchers carried out several subgroups analyses to examine the influence of different factors. These included patient age, whether the study also included mechanical valves, and risk of study bias.

Overall the risk of bias was assessed as low in 51 studies, moderate for 21, and high risk for 21 studies.

 

What did it find?

  • Pooled data from 85 studies estimated that 89.7% of people survived for two years after surgery, 78.4% at five years, 57.0% at 10 years, 39.7% at 15 years, and 24.7% at 20 years. Subgroup analysis showed that five-year survival declined with increasing patient age (from 83.7% in under-65s to 52.5% for those over 85).
  • The average (median) estimated survival after surgery was 16 years for patients aged 65 or less. This compares to a life expectancy of 22.2 in the comparative general US population. In those aged 65 to 75 median survival was 12 years (15.6 in the general population), seven years in those aged 75 to 85 (8.7 in the general population), and six years in those aged more than 85 (3.5 in the general population).
  • Structural valve deterioration was reported in 12 studies, including 7,703 people. There were 418 cases of valve deterioration during a median follow-up of 6.4 years, giving an estimated deterioration rate of 6% by 10 years, 19.3% by 15 years and 48% by 20 years.
  • Eight studies reported 64 strokes among 6,702 people. This gives a stroke rate of 0.26 per 100 person years (95% confidence interval [CI] 0.06 to 0.54), or less than one per 100 persons each year.
  • Two studies reported 21 cases of atrial fibrillation (abnormal heart rhythm) among 177 people. This gives a rate of 2.90 per 100 patient years (95% CI 1.78 to 4.79), or about three per 100 persons each year.
  • The average (mean) length of hospital stay in these studies was 12 days (95% CI 9 to 15) as reported by seven studies including 6,405 people.

 

What does current guidance say on this issue?

2014 NICE guidelines on management of heart failure recommend surgical aortic valve replacement for people with heart failure due to severe aortic stenosis, who are assessed as suitable for surgery.

NICE recommend transcatheter aortic valve implantation for people who are unsuitable for surgery. This involves accessing the aorta via a catheter inserted into an artery in the groin or chest.  However, the risks involved with this procedure mean that it is currently not recommended as an alternative for people otherwise suitable for surgery. This guidance is under review.

 

What are the implications?

This large review indicates that bioprosthetic valve replacement for severe aortic stenosis is safe and gives survival outcomes comparable to the general population without aortic stenosis.

The long-term deterioration of the valves suggests a need for regular monitoring to identify people who may require a further valve replacement, especially after ten years.

Comparable data on long-term patient outcomes following surgical mechanical valve replacement or transcatheter approaches would be valuable.

 

Citation and Funding

Foroutan F, Guyatt GH, O'Brien K, et al. Prognosis after surgical replacement with a bioprosthetic aortic valve in patients with severe symptomatic aortic stenosis: systematic review of observational studies. BMJ. 2016;354:i5065.

The authors declare no financial support from any organisation for this review.

 

Bibliography

British Heart Foundation. Heart valve disease. London: British Heart Foundation.

NHS Choices. Aortic valve replacement. London: Department of Health; 2016.

NICE. Acute heart failure: diagnosis and management. CG187. London: National Institute for Health and Care Excellence; 2014.

NICE. Balloon valvuloplasty for aortic valve stenosis in adults and children. IPG78. London: National Institute for Health and Care Excellence; 2004.

NICE. Sutureless aortic valve replacement for aortic stenosis. IPG456. London: National Institute for Health and Care Excellence; 2013.

NICE. Transcatheter aortic valve implantation for aortic stenosis. IPG421. London: National Institute for Health and Care Excellence; 2012.

NICE. Transcatheter valve-in-valve implantation for aortic bioprosthetic valve dysfunction. IPG504. London: National Institute for Health and Care Excellence; 2014.

Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre

 

Commentaries

Expert commentary

Patients with aortic valve stenosis have symptoms including angina, shortness of breath and tiredness. Aortic stenosis, if untreated, causes heart failure and reduces life expectancy. In the current era, surgical aortic valve replacement provides complete symptomatic relief with survival nearly similar to matched normal population with an overall operative mortality of 2% and stroke of 3% or less.

Patients generally stay in hospital for one week and take 2-3 months for complete rehabilitation. They can then enjoy a normal life style. Biologic valves are used in 70% of the patients where no need for anticoagulation or antiplatelet therapy is needed.  

Marjan Jahangiri, Professor of Cardiac Surgery, Department of Cardiothoracic Surgery, St George’s Healthcare NHS Trust

Expert commentary

When a patient receives an aortic valve substitute to replace their own obstructive valve they take on a new condition of “artificial heart valve disease”. This is a great improvement on what they had before, but these patients need life-long, expert surveillance. Bioprosthetic valves inevitably degenerate and this can be identified early by echocardiography.

A redo-procedure whether by surgery or by transcutaneous “valve-in-valve” wire-based procedure has a low risk provided the function of the left ventricle has not been allowed to deteriorate. A simple biological valve which can last for 20 years in 90% of patients remains a tantalising target.

Professor John Pepper, Consultant Cardiac Surgeon, Royal Brompton Hospital, London