Recent weeks have seen much debate about transcatheter aortic valve implantation (TAVI) as an alternative to valve surgery. Whilst TAVI is less invasive, the durability of the valve is uncertain and the stroke rate is twice as high as it is with surgery. Could the procedure be a ticking time-bomb for surgeons and patients alike?
Here, Which Medical Device summarises a recent research based report from the BMJ regarding TAVI procedures and offers comments in relation to this increasingly controversial topic.
British Medical Journal analysis
Researchers Dr Hans Van Brabandt, MD, Cardiologist at the Belgian Healthcare Knowledge Centre, Brussels and colleagues Mattias Neyt and Frank Hulstaert produced an analysis report on TAVI procedures for the BMJ which was published on 31 July. In the document, they expressed concerns with the treatment’s clinical outcomes and cost-effectiveness. They suggested that TAVI can be justifiable only for inoperable patients (around 10% of the aortic-valve-disease population) and that not a safe or cost-effective solution for patients who could undergo surgical valve replacement.
Brabandt and his colleagues analysed data related to TAVI including pivotal trials and approval proceedings in Europe and the U.S. which they amalgamated with information from correspondence with journal editors, federal agencies and sponsors. In an assessment performed for the Belgian government their conclusion was that the government should pay for only 10% of patients who are currently under consideration for a TAVI procedure.
In the report, the authors raised concerns about practices which they argued are not justified by clinical evidence, particularly the use of the transapical method. The authors recommended that marketing approval and reimbursement for a high risk device should be given for specific indications and said that routine use outside the indications would possibly put patients at risk. Their analysis found TAVI to be more costly than surgical valve replacement and added that the transapical approach was more expensive than the transfemoral approach.
They said, “Based on current evidence, and considering efficient use of limited resources, it is difficult to see how healthcare payers can justify reimbursing TAVI for patients suitable for surgery, given that the risk of stroke is twice as high after TAVI. If policy makers are willing to pay for TAVI, they should give priority to anatomically inoperable patients.”
Comment
Which Medical Device invited Dr. Azfar Zaman, a respected UK Consultant Cardiologist for his view on the BMJ’s analysis. He said, “The article in the BMJ was a provocative one and in my view asks important questions about the extent to which TAVI should be the procedure of choice for aortic stenosis. Note that even these critical authors did not question the impact of this device in the appropriate patient population. The seemingly uncontrolled expansion of TAVI, especially in Germany, has raised many eyebrows across the world and in economies struggling to pay for an already bloated health sector, questions will inevitably be asked of this and other medical technologies. So let the debate begin.”
Dr. Zaman went on to say, “There is little doubt that TAVI is effective for aortic stenosis. There is also little doubt that surgical AVR is currently the gold standard treatment for this disease of the elderly. So, for patients unfit for surgical AVR, TAVI is an effective, less traumatic option. We can argue about what is the “correct” penetration for TAVI in today’s population (the Belgian Government suggests paying for 10%) but in a sea of opinions, one important fact is that the population in industrialised nations continues to age. The figure of 10% will need to be revised upwards as the proportion of the electorate over the age of 70 increases and leads to reappraisal by the Belgian and other Governments.”
He concluded, “In summary, TAVI is effective and here to stay. The debate is no different than for any other medical procedure – not why but who?”
Valve implants
Two valves, Edwards Lifesciences’ Sapien valve and Medtronic’s CoreValve both received the CE approval Mark in 2007. In November 2011, the Sapien valve was given the go-ahead in the U.S. for treatment of inoperable patients with severe symptomatic aortic stenosis. In June this year, an FDA advisory panel recommended approval of the valve as treatment for patients with severe symptomatic aortic stenosis at high risk for surgery.
The medical device manufacturer told Which Medical Device, “Medtronic supports the diligent consideration of how to make new therapies available to patients so that their well-being is at the forefront of each decision. We call this “safe growth,” and this has been our mantra outside the U.S. where the CoreValve System has been available since 2007 and in the US where we are enrolling patients in our CoreValve U.S. Pivotal Trial. Through Medtronic-sponsored research, the CoreValve System clinical portfolio is studying more than 8,700 patients in 149 clinical sites worldwide. We are committed to providing industry-leading transcatheter therapy clinical research evidence.”
They went on to say, “We believe more data are needed to more accurately demonstrate the clinical benefit of TAVI for patients who are at lower risk, and that is why we have initiated the Medtronic SURTAVI Clinical Trial, which is the largest global, randomized controlled trial on TAVI patients. It is enrolling patients deemed to be at intermediate risk for open-heart surgery, and will compare the Medtronic CoreValve System with surgical aortic valve replacement (SAVR).”
‘Scope creep’ and evidence in medical device use - Phil Haslam, Consultant Interventional Radiologist, UK
An important trend is brought to light in the recent BMJ article on the use of TAVI in Europe (1). New medical devices can be exciting. They bring new ways to treat conditions, often non-surgically or minimally invasively. There is the promise of reduced morbidity/mortality and reduced cost to the healthcare provider and therefore the taxpayer and patient. There is also the promise of increased profits to the device manufacturer. However we need to ask ourselves the following questions before using new devices:
- Does the device do the same job as the ‘Gold Standard’?
- Who should be treated with the new device?
- What are the long term success rates?
- What are the short term/long term complication rates?
- How much does it cost?
The best way to answer some of these questions is with a randomised controlled trial with the Gold standard treatment. Trials can be flawed in many ways and should be open to scrutiny and criticism as by Brabandt (1). If a trial shows superiority of a minimally invasive treatment using a certain device in a specific patient group then it would be reasonable to offer that treatment to patients who fall within the same criteria if cost was not a consideration.
If the treatment is more cost effective then the decision is easy. The problem lies with devices/treatment modalities where there is debatable efficacy and where the cost effectiveness is unclear. There is more of a problem when the device/treatment is offered to a group of patients in whom there is no evidence of benefit or even evidence of less favourable outcome. Randomised controlled trials can also become impossible to recruit to if the public perceive that a new treatment/device can offer a less invasive alternative. I believe just such a scenario has led to the widespread adoption of venous stenting in patients with multiple sclerosis. There is as yet no convincing evidence that this treatment for a possibly hypothetical condition (CCSVI) causing MS actually works.
So, why has TAVI use extended to include patients in whom open surgery is a good option when the evidence only supports its use in patients unfit for surgery? This is partly because TAVI tends to be performed by cardiologists and AVR by cardiothoracic surgeons. If patients are seen in a healthcare system where good MDT meetings do not occur, then it is likely they may be offered the treatment that the clinician whom they see can offer i.e. if they see a cardiologist then they may be offered TAVI and the converse for a cardiothoracic surgeon. There can also be a certain amount of ‘turf war’ and even financial incentives that can exacerbate this problem.
Patients should ideally be discussed in a team setting with clinicians from both specialties involved. In this way the patient is more likely to be offered the correct evidence based procedure. Another factor in incorrect patient selection is lack of awareness of or even distrust of the current literature amongst clinicians. For example, there is convincing evidence for fibroid embolization, yet this option is not even discussed with patients by some gynaecologists.
More rigorous device regulation is helpful if it means that devices are truly fit for purpose and clear indications for use are set out and based on good evidence. Evidence may however be hard to come by and is not always followed by even the most well read clinicians. It is understandable that an experienced cardiologist who performs TAVI on unfit patients may be tempted to extend the range of patients he treats into an area that is not supported by the current evidence. Innovation is good, but as we continue to push the boundaries of what we can offer we need to be wary of straying into areas that can lead to harm.
User comments: Is the transcatheter valve procedure (TAVI) a ticking time-bomb?
Which Medical Device would value your opinions
Following the BMJ article mentioned in the our Editorial and the potential for devices being used beyond their initial intended purpose, we'd very much like to hear your opinions, which we’ll publish as part of the on-going debate. Do you routinely use a device for a particular condition that seems logical but has no published evidence base to support it?
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Source of Reference:
(1) Van Brabandt H, Neyt M, Hulstaert F. Transcatheter aortic valve implantation (TAVI): risky and costly.
BMJ 2012;345:e4710.
