Devices with Heart

18 August 2008 (Last Updated August 18th, 2008 18:30)

Cost vs benefit has become a major talking point in heart surgery. Steve Rogerson looks at the latest technologies available.

Devices with Heart

As the population steadily grows older, ever more people find themselves suffering from some form of heart disease. Though this has been offset to a degree by preventative drugs and an increased awareness of lifestyle choices that protect the heart, hospitals are still having to deal with larger numbers of patients that need some form of cardiovascular treatment.

This has put increased budgetary pressure on medical service providers that are already struggling with financial constraints across the board. Heart surgery does not come cheap, hence an ongoing quest to find cheaper, longer lasting methods to keep heart systems healthy.

Controversial treatments

Nowhere is this better illustrated than in the current row over stents. Stents are thin metal tubes that can be inserted into an artery and then expanded to keep the artery open and the blood flowing.

Stents in the past were never a problem until the invention of a tube coated in drugs which claims to extend the life of the stent and reduce the chance of the patient needing bypass surgery. These are known as drug-eluting stents, or DESs. The snag is that they cost about three times as much – £300 against £900.

The National Institute of Health & Clinical Excellence, known as NICE, initially banned and then restricted the use of DESs in the UK's NHS. This caused an outcry with critics claiming that patients' lives were being put at risk because of cost-cutting measures. The truth, however, is not as straightforward.

"Heart surgery does not come cheap, hence an ongoing quest to find cheaper, longer lasting methods to keep heart systems healthy."

"The most recent tests have shown that there is not that much difference between the two types of stent," says Terry O'Brien, CEO at medical equipment supplier Lidco. "The other question is whether they are better than doing open heart surgery and doing it properly. There is controversy here and we need more studies over a considerable period."

Ellen Mason, senior cardiac nurse at the British Heart Foundation, says that for some patients the normal stents were actually better.

"With DESs, there is an increased risk of getting a blood clot in the stent," she explains. "You need drugs to thin the blood for years. They also carry other risks, which is why we are saying that not everyone should have them."

Another area surrounded in controversy is the use of stem cells, and much of the work here is in the early days but there are clinical trials and hospitals such as UCH in London and Barts & The London are treating heart attack patients with stem cells.

"They are entering some people with heart attacks into research trials," says Mason. "They inject some of the patient’s own stem cells into the heart."

The procedure involves opening up the artery with a metal stent and then through this injecting some of the patient’s own stem cells taken from bone marrow near the hip (not a pleasant experience). These stem cells should then help the heart's muscles repair themselves.

Temporary or permanent solutions?

Still popular in heart treatment are left ventricular assist devices (LVADs) introduced more than ten years ago. These are artificial pumps that can be used either inside or outside the body and are designed to be temporarily used to help a patient while they recover or to keep a patient alive while they are waiting for a transplant donor to become available. But as they have become smaller, they are now being considered as a more permanent option.

"With DESs, there is an increased risk of getting a blood clot in the stent. You need drugs to thin the blood for years."

"Recent clinical trials have provided evidence that they are of value for long-term use as destination devices, that is permanent therapeutic implants," said Kenneth Krul earlier this year in a research paper for Kalorama Information.

A step up from this is the Berlin Heart, a ventricular assist device named after the German company that makes it. This works on both the right and left ventricles and can be used on all ages of patients from newborn to the elderly. This sits outside the body and can be on wheels so it can be moved around with the patient.

"It looks like a small suitcase," says Mason. "Though it is mainly a bridge to recovery, it can be more permanent for those who are not suitable for transplant. For example, some children may not survive a transplant but this may buy them a few more years."

Biventricular pacemakers also stimulate both ventricles rather than just the left ventricle as with a normal pacemaker. These are useful for people with heart rhythm problems to keep the heart in sync. They can also be combined with defibrillators. However, they are much more expensive and the benefits are not that clear cut.

"There is controversy over whether the biventricular pacemakers are really better than single ventricular ones given they are far more costly," says O'Brien.

Pacemakers and other heart monitoring devices are also copying consumer electronics in that they are being embedded with communications facilities, such as Bluetooth, and memory to store data on what has been happening to the patient. This information can be transmitted to the hospital over the mobile phone networks, allowing patients to spend more time away from the hospital.

Innovative surgical aids

"Recent clinical trials have provided evidence that LVADs are of value for long-term use as destination devices, that is permanent therapeutic implants."

A number of medical devices and techniques have come about to avoid open heart surgery. For example, replacing a valve can involve a three to four-hour operation with a 5% mortality risk. An alternative here is percutaneous valve replacement where the new valve is inserted through tube in either the leg or groin. This is still in an experimental stage with only a small number of hospitals involved.

"This could be a great way to do valve surgery," says Mason. "You can do it under local anaesthetic. We hope this is the way all valve surgery will go."

Because of the way the surgery is done, a metal valve cannot be used so it has to be a tissue valve, using human, cow or pig tissue. The valve is folded and then unfolded when in place. One potential difficulty would arise when trying to remove the valve.

"We don't know how to take them out," Mason explains. "And you need to replace tissue valves every few years because they wear. This is why it is experimental. We need to see what happens to these people and if it still works properly in years to come."

Nevertheless, this is clearly the trend in an era when value for money is so strong in the health world. Opting for cheaper methods could also be beneficial.

"We are trying to develop ways that are less invasive, cause less blood loss and are less traumatic for the patient," says O'Brien. "This means the patient spends less time in hospital and the risks are reduced."