Promising substitutes for human hearts
Fully implantable mechanical hearts bring hope to 121,000 heart failure patients who will never receive a heart transplant
It is a world-first. In December 2013, a fully artificial heart was implanted in a 75-year-old French man, who is continues to be doing ‘very, very well,’ according to surgeons.
This year three more French patients with end-stage heart failure are expected to receive mechanical heart replacements as part of this first-in-man trial for safety and feasibility. If all goes well, a second group of 20 patients from Germany, Belgium, Poland, Slovenia, and Saudi Arabia will receive hearts in an expanded clinical trial that could lead to CE approval in 2015.
It is estimated that each year 125,000 end-stage patients in the United States and Europe are awaiting a heart transplant, where only 4,000 transplants will be performed.
We have heard about heart failure patients receiving heart-assist devices that serve as a bridge-to-transplantation, keeping them in life while waiting for a human heart to become available. Yet this was the first patient to have his heart completely replaced by a mechanical device that is a destination therapy. If all goes well, that is first French patient will leave the hospital wearing only a lithium-ion battery in a shoulder harness.
‘This is completely new, a fully implantable artificial heart and not a ventricle assist device,’ explained Marcello Conviti, CEO of Carmat, the company that developed and manufactures the device.
‘Ventricle assist devices are used as a bridge-to-transplant, and they work well. However, these devices need an external air compressor that drives the membrane to push the blood. There are also tubes exiting the patient. With the Carmat heart only a wire exits the body to supply electricity and give information about device performance. All the other parts are inside the patient,’ he explained in an interview with European Hospital.
A heart from outer space
Developed by a team of engineers from EADS, the Carmat heart weighs 900 grams, nearly three times more than an average healthy human heart. ‘What is significant is the level of innovation in our approach.
All the parts that are in contact with the blood are made of biocompatible materials, the same as have been used in artificial heart valves. This should reduce dramatically the level of anti-thrombotic drugs required because the risk of thrombosis is extremely low, compared to ventricle assist devices.
‘Our device is also auto-regulating with embedded electronics, so it’s going to deliver output in line with a patient’s needs, from two to nine litres per minute. There are sensors to optimise the machine’s performance for cardiac output according to the patient position and activities.
‘The other devices in the market have pumps that deliver a fixed level of output. This makes a very big difference because it affects not only the quality of life of the patient but the level of precision will maintain a level of health for the patient. ‘The Carmat heart is also silent so the patient does not have noise around him,’ Marcello Conviti added. ‘With heart-assist devices, the patient has a big compressor pumping air in and out with mechanical valves that you can hear clicking,’
The service life of the device is estimated to be five years. ‘We have done bench testing that shows device performance goes well beyond five years,’ he explained. ‘But time will tell. In bench testing it was very difficult to simulate beyond 10 years.’
Exceeding all expectations: valves run beyond 10 years
Carpentier heart valves, invented by Alain Carpentier MD, a founder of Carmat and the driving force behind the artificial heart, were expected to fail after two years, ‘because all the previous generations of artificial heart valves had failed due to calcification; but, after five years, the Carpentier valve was still going, performing very well,’ Marcello Conviti pointed out. ‘Then these valves performed beyond 10 years. Currently there is a large series of Carpentier biological valves, and they are still performing after 30 years.‘The cost for the heart device cost and implantation procedure is between €140,000 to €180,000, roughly equivalent to reimbursement levels for a heart transplant, a key to the design requirements set down by Dr Carpentier. ‘What good is there in developing a device if it is too costly to be used for everybody,’ he told the French Sunday newspaper, Le Journal du Dimanche.
Carmat’s CEO said he is prudent in his estimations of the value of the business potential for providing hearts off an assembly line. ‘We do not provide any guidance at this point, except to say that we hope to start commercial activities in 2015, to be in the USA in 2018, and to reach full capacity with revenues of $1.5 billion in 2020 – something like that. We are talking about a company that has only one product for the moment, and which has not yet sold anything, yet.’
03.03.2014
