NIHR Signal Transcatheter aortic valve implantation may be an option for patients with aortic stenosis at lower surgical risk
Published on 17 September 2019
Transcatheter aortic valve implantation (TAVI), the less-invasive procedure, may be associated with a reduced risk of death and stroke for up to two years when compared with surgical aortic valve replacement for adults with severe narrowing of the aortic valve, irrespective of the level of surgical risk.
TAVI is already an established procedure for those unsuitable for surgery or at high risk. This meta-analysis evaluated seven trials comparing 8,020 adults treated with one of these procedures who had any level of surgical risk, including those at low surgical risk.
At present, NICE guidance recognises the use of TAVI as a safe and effective method but outlines open heart surgery as the first line of treatment for those at low surgical risk. This review backs the idea of TAVI now being used in a wider group of patients; however, there is still a balance of risks to be considered that requires a discussion of patient preference.
- Cardiovascular system disorders, Surgery, Acute and general medicine
Why was this study needed?
Heart valve disease affects approximately 1.5 million people over the age of 65. The most common type is aortic stenosis (narrowing), which is responsible for 43% of cases.
Symptoms of aortic stenosis include breathlessness, chest pain, dizziness and fainting. Over time, the condition can become disabling. Open heart surgery has been the standard of care for individuals with aortic valve disease and who are at low risk for surgery for many decades. TAVI is a less invasive method that over ten years has been available to those considered unsuitable for open heart surgery or at high surgical risk.
The researchers wanted to evaluate new evidence available since the previously published version of this meta-analysis in 2016. The aim was to compare the safety and effectiveness of the procedures across patients of varying surgical risk.
What did this study do?
This systematic review and meta-analysis included seven trials where patients with aortic stenosis were randomised to receive open heart surgery or the less invasive TAVI to replace the aortic valve. Observational studies were excluded.
The trials included 8,020 adults and reported outcomes for at least one year post-surgery. The main outcome was death from any cause within two years of surgery. Other outcomes included stroke, disabling stroke, death from stroke or heart disease, and non-fatal heart attack.
Assessment of the long-term effects and durability of the replacement valves beyond two years was not possible in this review. It is possible that patients were not selected for these trials if their clinicians thought they might do better with surgery. Therefore, results should be treated with caution.
What did it find?
- Findings showed that TAVI was associated with fewer deaths from any cause when compared with open surgery for people at any surgical risk levels (hazard ratio [HR] 0.88, 95% confidence interval [CI] 0.78 to 0.99).
- TAVI was associated with a significant reduction in stroke events (HR 0.81, 95% CI 0.68 to 0.98) but not disabling stroke (HR 0.78, 95% CI 0.53 to 1.14), deaths from heart disease or stroke (HR 0.93, 95% CI 0.80 to 1.08) or heart attacks (HR 0.92, 95% CI 0.68 to 1.25).
- TAVI was associated with a significantly higher risk of major vascular complications (HR 1.99, 95% CI 1.34 to 2.93) and permanent pacemaker implantations (HR 2.27, 95% CI 1.47 to 3.64) compared with open surgery.
What does current guidance say on this issue?
2014 NICE guidance covering valvular surgery recommends offering open surgery to people with heart failure due to severe aortic stenosis who have been assessed as suitable for surgery. In people considered unsuitable for open surgery, TAVI should be considered.
2017 NICE interventional procedures guidance supports the safety and efficacy of TAVI for aortic stenosis. The guidance recommends that an experienced cardiology multidisciplinary team determine patient selection and surgical risk level.
What are the implications?
Findings suggest that TAVI was associated with lower risk of death and stroke compared to open surgery for up to two years in patients with severe aortic stenosis, but there was a higher risk of major vascular complications and pacemaker implantation.
Longer-term follow-up of patients from these trials or using the existing registries will further define the selection of the important group of patients who may still do better with open surgery. The data on benefits and risks will be useful in informing discussions between surgeons, patients and their families.
Citation and Funding
Siontis GCM, Overtchouk P, Cahill TJ et al. Transcatheter aortic valve implantation vs. surgical aortic valve replacement for treatment of symptomatic severe aortic stenosis: an updated meta-analysis. Eur Heart J: 2019;(0):1-11.
No funding information was provided for this study.
British Cardiac Patients Association. Aortic stenosis and its treatment. Nottingham: BCPA; 2017.
Heart Valve Voice. The condition. Manchester: Heart Valve Voice; 2016.
NICE. Transcatheter aortic valve implantation for aortic stenosis. IPG586. London: National Institute for Health and Care Excellence; 2017.
NICE. Acute heart failure: diagnosis and management. CG187. London: National Institute for Health and Care Excellence; 2014.
The generalisability of the results of this review to real-world practice is offset by several factors.
First, TAVI device manufacturers funded all but one of the included trials. Second, the trial cohorts were highly selected and typically excluded patients who clearly would have benefited from surgical replacement. Third, the length of follow-up was relatively short. Longer-term follow-up would tend to favour surgical replacement where there is high-quality evidence of sustained improvements in health and wellbeing for at least a decade post-surgery.
The evidence presented heralds a new phase in the treatment of severe symptomatic aortic stenosis; however, it is not yet sufficient to demonstrate that TAVI is the gold standard.
Gavin Murphy, British Heart Foundation Professor of Cardiac Surgery, University of Leicester; Honorary Consultant Cardiac Surgeon, University Hospitals of Leicester NHS Trust
The commentator declares no conflicting interests