Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gene variants predict bleeding after heart surgery

04.05.2005


Duke University Medical Center researchers have found that the presence of specific variants of genes that control clotting and the contractility, or "tone," of blood vessels can double the ability of physicians to predict those heart surgery patients at greatest risk of bleeding after surgery.



The issue of post-operative bleeding is important, the researchers said, because patients who suffer such episodes have increased rates of additional medical problems and even death. Furthermore, decreasing the rate of postoperative bleeding can have important implications for the health care system, they continued, since an estimated 20 percent of the nation’s blood supply is used to treat these patients.

"While larger studies are needed to investigate the genetic associations we have uncovered, if our observations are confirmed, genetic screening could become an important part of our pre-operative evaluation of heart surgery patients," said Duke anesthesiologist Ian Welsby, M.D., lead author of a study to be published in the June edition of the Journal of Thrombosis and Haemostasis but appearing early on-line.


Currently, physicians base their predictions of who is likely to bleed on such patient characteristics as weight, size and blood count. In their consideration of risk, they also take into account factors that may come into play during the actual surgery, such as the number of vessels being bypassed, the degree of atherosclerotic disease and use of the heart-lung machine to keep blood pumping while surgeons operate on the stopped heart.

"However, these risk factors we use now are poorly predictive of which patients are more likely to bleed," Welsby continued. "Also, these factors are only partially successful in accounting for the striking variability in outcomes among patients undergoing heart surgery."

Within the circulatory system, three main factors control bleeding or clotting – blood vessel constriction, platelet activation and the activity of clotting factors that circulate in the blood. Abnormalities in any of these areas can lead to potentially dangerous bleeding or clotting.

According to Welsby, past studies have demonstrated a genetic component to the activation of platelets and clotting factors. However, since there has only been one study that focused on a single variation -- or polymorphism, in connection with post-surgical bleeding, the Duke team believed that multiple genes and their interactions may be involved.

The researchers first selected 19 different polymorphisms of 13 candidate genes that past studies have shown have an effective on the blood’s ability to clot. They then correlated genetic information from blood samples taken from 780 patients prior to heart surgery at Duke University Hospital with the amount of bleeding after surgery.

"Genetic analysis revealed that seven polymorphisms of platelet surface receptors, coagulation proteins and angiotensin converting enzyme (ACE) demonstrated a significant association with increased bleeding after heart surgery," Welsby said. "These genetic factors are independent of the clinical characteristics used to predict bleeding and appear to explain at least as much of the variation seen among patients.

"For this reason, we believe that adding the genetic information to our existing risk stratification factors should be able to double our ability to predict who is at greatest risk of bleeding, "Welsby continued. "While substantial variability in bleeding remains unexplained, these novel genetic approaches may have the potential to expand our understanding of bleeding after heart surgery."

Welsby said he found it interesting that one of the polymorphism (ACE D/I) was for a gene involved in vascular tone, the ability of vessels to contract or expand appropriately, which represents a new line of research that should be pursued along with the traditional blood clotting factors.

As is true of many genetic analyses, the current study cannot explain the mechanisms involved in the increased risks, said Welsby. He said that further studies will be needed to better understand not only the roles of the polymorphisms that have been identified, but the interactions between them and other potential genetic variants.

Welsby also said that a better knowledge of who may be at risk for bleeding would be useful because there are effective, though expensive, drugs that are currently reserved for those patients at highest risk, based on their clinical characteristics.

Earlier this year, members of the same research team found that patients with a different set of polymorphisms were at a two to four times as likely to suffer kidney damage as a result of major heart surgery.

The research was supported by the National Institutes of Health, the American Heart Association and Bayer Pharmaceuticals Corp.

Other members of the team, all from Duke, are: Mihai Podgoreanu, M.D., Barbara Phillips-Bute, Ph.D., Joseph Mathew, M.D., Peter Smith, M.D., Mark Newman, M.D., Debra Schwinn, M.D, and Mark Stafford-Smith, M.D. All are members of Duke’s Perioperative Genetics and Safety Outcomes Study (PEGASUS) team.

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

More articles from Life Sciences:

nachricht One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie

nachricht The dark side of cichlid fish: from cannibal to caregiver
20.04.2018 | Veterinärmedizinische Universität Wien

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>