Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Implantable pumps extend lives of patients too sick for transplant

15.11.2005


Pumps implanted into the chest to maintain circulation can significantly extend the lives of the sickest patients in end-stage heart failure who are not candidates for heart transplantation, according to the results of a clinical trial led by Duke University Medical Center cardiologists.



The pumps, known as left ventricular assistant devices (LVADs), are employed when the heart’s left ventricle – the chamber of the heart that pumps blood throughout the body – is too weak to pump enough blood to nourish the body’s tissues. LVADs have been used as successful short-term "bridges to heart transplant" and are increasingly being considered as a long-term heart failure destination therapy, said the researchers.

In the current trial, the researchers found that patients who received LVADs had an average survival time of 10.3 months, compared to 3.1 months for those who did not receive the device. In this group of end-stage heart failure patients, 78 percent died within six months and 90 percent within a year.


"The patients who received the devices not only had a lengthened quantity of life, but they appeared to have an improved quality of life," said Duke cardiologist Joseph Rogers, M.D., who presented the results of the trial Nov. 14, 2005, at the annual scientific session of the American Heart Association meeting in Dallas. "We had patients who were doing the normal activities of life, such driving cars, fishing and golfing."

Patients who were on the LVADs scored significantly higher on standard measures of quality of life than patients in the control group, Rogers said.

"This is a remarkably ill group of patients," Rogers continued. "When you look at the control group, which was receiving the best care medicine has to offer, we can only keep ten percent of them alive after one year. We need to focus on this as a group of patients, since most are still in the prime of life and can still be quite productive."

To be considered for the trial, patients had to be taking powerful intravenous drugs in the hospital just to keep their hearts pumping, and they were also too sick to be considered for a heart transplants. Most were in intensive care units.

"Despite the shortcomings of the device, the results of this trial speak to our ability to improve the functionality for a very sick group of patients," Rogers said. The major complications of LVADs, said the researchers, include stroke, bleeding episodes and infections, especially at the site in the side of the body where the pump is connected to an external power source and computer.

"We already had a lot of data on the device when it was being used as bridge to transplantation," he continued. "We knew it could go for extended periods without problems, and that was the most compelling argument to use for implanting the device in patients who have no other options."

For the trial, researchers enrolled 55 patients from 2000 to 2003. Thirty-seven patients received the device and 18 did not. Patients were on average of 59 years old and as a group their hearts beat at only 14 percent of normal strength. The pump tested in the trial was the Novacor device, which is produced by WorldHeart, Oakland, Calif.

"While the survival time for those patients receiving LVADs was more than three times longer, we even had two patients who are both four years out from implantation," said Rogers. "Furthermore, unlike some earlier studies, there were no catastrophic mechanical failures."

According to Rogers, there are a number of challenges to be addressed before the use of LVADs can be considered as a widespread destination therapy.

The first challenge is selecting appropriate patients, which is crucial, since the patients most likely to survive would be those who are quite sick, but not too sick to be beyond help. This fine line in determining which patients are optimal will need to be defined by future clinical trials, he said. The other challenges pertain to the limitations of LVAD technology.

"Like most new technologies, we’re limited by our power supply," Rogers said, "We need to develop a battery that is not only small enough and powerful enough to be safely implanted into the human body, but one that could be recharged through the skin without burning the skin. That way there would be no external parts, which would greatly reduce the incidence of infection."

Another technological challenge involves the pump itself, Rogers said. The Novacor device is a pulsatile pump which contains blood in a polyurethane sack. The blood is then propelled out of the pump between two pusher plates. However, because of its size, it cannot be used in children or comfortably in small women. Rogers said that numerous pump designs are being tested that are smaller and lighter. Durability will also be an issue, he said, since replacing an LVAD entails just as substantial and involved a surgical procedure as the initial placement.

Duke is currently participating in a number of different trials testing different device models and pumps designs.

Richard Merritt | EurekAlert!
Further information:
http://www.mc.duke.edu

More articles from Health and Medicine:

nachricht Penn vet research identifies new target for taming Ebola
12.01.2017 | University of Pennsylvania

nachricht The strange double life of Dab2
10.01.2017 | University of Miami Miller School of Medicine

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>