Focus on: Left ventricular assist devices

Diagram of a left ventricular assist device

For people with severe heart failure, every breath can be a struggle. Steven Tsui, Clinical Director of Transplant Services at Papworth Hospital, talks to June Davison about how LVADs can act as a bridge to a heart transplant.

Why do some people need a left ventricular assist device (LVAD)?

An LVAD is a kind of artificial heart pump. It is used to treat people with severe heart failure and is sometimes given to people on the waiting list for a heart transplant. Normally, the left ventricle, one of your heart’s four chambers, pumps blood into your aorta (the large artery leaving the heart) and around your body. In the event that someone has severe heart failure, the heart is too weak to pump enough blood around the body.

Some patients being considered for a heart transplant may need to have an LVAD implanted if they are unlikely to survive until a suitable donor heart becomes available. The device helps the failing heart and aims to restore normal blood flow.

Is everyone with heart failure considered for an LVAD?

"Implanting an LVAD can be life-saving and buys more time for the patient until we can find a suitable donor heart"

Heart failure usually develops because the heart has been damaged by a heart attack, or as a result of other conditions such as cardiomyopathy – a disease of the heart muscle. Some patients who have very severe heart failure, which cannot be managed with medicines or other treatments may be considered for a heart transplant.

However, during the wait for a suitable donor, some patients continue to deteriorate. In these cases, implanting an LVAD can be life-saving and buys more time for the patient until we can find a suitable donor heart.

How does an LVAD work?

Having an LVAD is a big operation and involves open heart surgery. We attach one end of the LVAD pump to the left ventricle and the other end to the aorta. Blood flows from the ventricle into the LVAD. The device pumps the blood out into the aorta, where it then flows to the rest of the body.

A fine cable called the driveline connects the LVAD, which is inside the body, through the skin and to a controller, which is outside the body. The controller senses the function of the LVAD and controls the power to make it work. The controller connects to an external battery pack.

How reliable is its battery power?

People’s lives depend on their LVADs working properly, so the device needs to be extremely reliable and have built-in safety systems.

If the battery starts to run low, an alarm sounds to let the person know that it needs changing. An additional battery is always connected to the controller, so if one battery runs down, there is another to power the LVAD for several more hours. Additionally, there is back-up circuitry in the controller, so if the primary circuitry happens to fail, the back-up system kicks in. Modern LVADs are, therefore, very reliable and can support patients for years.

People can choose how they wear their controller and the two batteries. They can put everything into one pack and carry it as a shoulder bag or rucksack. Or they can separate the components and wear them on a belt with a loop, like you might with a camera or mobile phone.

Everyone is given a portable charger when they leave hospital, so they can charge the batteries anywhere. They are also given an adapter to plug the charger into a car cigarette lighter, so the battery can be recharged during long journeys.

LVAD facts

Approximate number of people in the UK currently living with an LVAD 100

Average number of hours that an LVAD battery lasts 4-6

Number of heart transplants performed in the UK in 2011/12 138

Approximate number of Britons who have an LVAD implanted each year 80

What difference do LVADs make to your patients’ lives?

Most patients who are considered for an LVAD have a very limited quality of life before the operation. They feel tired, weak and are very breathless. Some have difficulty getting washed and dressed and they might not be able to leave the house.

As soon as the LVAD is implanted, the blood supply to the body returns to normal, so heart failure symptoms improve. Patients who have been too unwell to walk around are quickly able to get up and about. Many patients can soon return to other normal activities like driving and going on holiday; some of them even return to work.

How do LVADs act as a bridge to transplant?

There can be a long wait for a heart donor, so we may consider an LVAD to keep someone alive and well until a suitable match can be found. Ironically, because many patients get so much better after receiving an LVAD, some become a lower priority on the heart transplant list as a result. This is because there’s often someone sicker (who doesn’t have the device) who is more in need of a transplant.

The longest that we’ve supported a patient for with an LVAD has been five and a half years. Nowadays, 80–85 per cent of patients are alive a year after having an LVAD fitted and 70–75 per cent after two years. This is fantastic considering that many of them would only have had a life expectancy of 12 months or less before their LVAD treatment.

What does the future hold?

"In the future, having an LVAD fitted could potentially become an alternative to a heart transplant"

Technology has come an amazingly long way in the past decade, with devices becoming smaller and more sophisticated. We are looking forward to further improvements in battery technology, so that they carry their charge for longer and become smaller, lighter and more portable.

We are very excited about the potential of wireless devices becoming available in the next few years. With these, the LVAD, controller and batteries all sit inside the person’s body and the batteries are charged through a coil placed on the surface of their skin. This will be fantastic as there’ll be no driveline outside the body – so we won’t have to worry about it being damaged. In the future, having an LVAD fitted could potentially become an alternative to a heart transplant.

Read Chris's story of having an LVAD

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