Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Implanted defibrillators cut heart patients’ death risk, some more than others

09.11.2004


Doctors must choose and manage ICD patients carefully

Implanted devices that can shock a failing heart back into regular rhythm do an excellent job of keeping patients alive, two new University of Michigan studies find. The research also suggests that doctors may be able to categorize their patients according to their individual risk factors, to determine who might get the largest benefit from the expensive devices, called implanted cardiac defibrillators, or ICDs. The studies also reinforce the importance of providing good follow-up care to all heart failure patients, whether or not they receive an implanted device.

With Medicare poised to start covering ICDs for many more patients than ever before, the new results come just in time to help doctors decide which patients might get the greatest benefit from the costly devices. More than half a million more people may qualify for ICDs, which cost around $20,000, under Medicare guidelines that will take effect soon.



The data were presented here today in two talks at the Scientific Sessions of the American Heart Association by a U-M Cardiovascular Center team that analyzed data from 7,000 veterans treated for heart trouble in Veterans Affairs hospitals between 1995 and 1999. All had congestive heart failure, heart muscle damage caused by clogged blood vessels, and a heart rhythm irregularity called ventricular arrhythmia. Of the 7,000 patients, 1,442 had received an ICD.

The researchers found that those who received an ICD were 60 percent less likely to die in the next year, and 48 percent less likely to die in three years, than those who did not receive an ICD. Most of this reduction in death risk was due to reduction in heart-related deaths. ICDs are specifically designed to prevent sudden cardiac death, in which the heart’s electrical system goes haywire, causing it to stop beating.

But ICD recipients who had co-existing medical conditions, especially diabetes or kidney failure, were much more likely to die within a year of getting the device than other patients. So were patients who received an ICD, but didn’t get heart-protecting medications that are part of standard heart-failure therapy.

It’s the first "real world" study of the effect of ICDs on mortality rates among heart failure patients with ischemic heart disease treated outside of clinical trials, says lead researcher and U-M cardiology fellow Paul Chan, M.D. "We need to make sure that as this technology is disseminated out of the carefully controlled environment of clinical trials and into the broader population, we assess whether the benefit seen in those trials is sustained," says Chan. "And indeed, we see that those who received an ICD had significantly less mortality," he continues. "For every five people with heart failure and ischemic heart disease who received an ICD, one life was saved over three years. But those with certain pre-existing conditions were more likely to die within a year, despite the benefits of ICDs."

In all, 20 percent of patients who didn’t receive ICDs died of heart-related causes by the end of the first year after their hospitalization, compared with 8 percent of those who received ICDs. By the end of three years, 36 percent of patients who didn’t receive ICDs died of heart-related causes, as compared with 23 percent of those who did. Death rates due to non-heart causes were similar between the two groups.

Chan and his mentor, U-M internal medicine professor and VA Ann Arbor Healthcare System researcher Rodney Hayward, note that the finding of major differences in mortality benefit among different patient groups should help doctors decide which patients are less likely to die within a year of ICD implantation, and how to manage them after they’ve received the device.

The veterans in the study who received ICDs were classified into four groups, depending on the number of points they scored on a measurement of how many co-existing conditions they had and how many heart medicines they were on. The higher the score, the higher the patient’s risk. The researchers found that 28 percent of those in the highest-scoring group died before the end of one year, as compared with only 2.2 percent of those in the lowest-scoring group. Part of this difference was due to pre-existing diabetes, kidney failure, high blood pressure and clogged blood vessels in other parts of the body. For example, the rate of diabetes among ICD patients who died before a year was 42 percent, compared with 31 percent who among those who survived. Similarly, kidney failure was more common among the ICD group that died before the one-year anniversary of their implantation than among those who lived -- 17 percent compared with 5.7 percent.

Moreover, failure to control some of those pre-existing conditions, such as high blood pressure, with medications such as beta blockers, ACE inhibitors and angiotensin II receptor blockers was associated with a higher likelihood of death within a year of ICD implantation. "Physicians need to realize that once they implant an ICD, they can’t relax -- the patient isn’t home free," says Chan. "We need to ensure that patients receive established cardio-protective medications that can add to the benefit delivered by the ICD." But, he adds, in heart failure patients who don’t have serious co-existing conditions and who are able and willing to keep up with their drug regimens, "There’s no excuse for not putting in an ICD. We already know it’s cost-effective, and now we can see from real-world evidence that it provides a true reduction in mortality."

In addition to Chan and Hayward, who directs the VA Health Sciences Research & Development Center at the Ann Arbor VA Healthcare System, the research team included data analyst Jenny Davis and Mark Starling, M.D., who directs the Ann Arbor VA cardiology division and the U-M cardiology fellowship program.

Kara Gavin | EurekAlert!
Further information:
http://www.umich.edu

More articles from Health and Medicine:

nachricht Correct connections are crucial
26.06.2017 | Charité - Universitätsmedizin Berlin

nachricht One gene closer to regenerative therapy for muscular disorders
01.06.2017 | Cincinnati Children's Hospital Medical Center

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: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Touch Displays WAY-AX and WAY-DX by WayCon

27.06.2017 | Power and Electrical Engineering

Drones that drive

27.06.2017 | Information Technology

Ultra-compact phase modulators based on graphene plasmons

27.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>