Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

No benefit to mechanically opening arteries days after a heart attack

15.11.2006
Study warrants a major change in practice in treating tens of thousands of patients

In the days following a heart attack, patients who have no or mild symptoms and undergo a procedure called angioplasty to mechanically open their totally blocked coronary arteries do not reduce their risk of having another heart attack, going into heart failure, or dying, according to the results of a new study.

Opening arteries that are 100 percent blocked in the first 12 hours after a heart attack with angioplasty can quickly restore vital blood flow to the heart, and is considered optimal treatment for almost all patients. However physicians in the United States often open blocked coronary arteries with angioplasty in stable patients who are beyond this treatment window, although there aren't any definitive clinical trials addressing this practice.

The study, called the Occluded Artery Trial or OAT, evaluated whether opening arteries three to 28 days after a heart attack benefited patients over the long term. It was designed to provide definitive answers to questions about this practice.

"OAT was created to help resolve a controversy that affects more than 100,000 heart attack survivors each year in the U.S. alone," said Judith S. Hochman, M.D., Director of the Cardiovascular Clinical Research Center at NYU School of Medicine and the lead author of the new study. She estimated that some one-third of eligible patients do not receive therapy to open blocked arteries within the treatment window often because they arrive too late at the hospital.

The study is being published in an early on-line edition of the New England Journal of Medicine to coincide with a presentation of the results by Dr. Hochman on November 14 at the annual meeting of the American Heart Association in Chicago. The study, which was funded by the National Heart, Lung, and Blood Institute of the National Institutes of Health, is expected to be published in Dec. 7, 2006, issue of the journal.

"We had expected that angioplasty to open arteries would reduce the risk of subsequent clinical events, specifically heart failure and death in this population that was stable after the initial heart attack but at increased risk of events in the future," said Dr. Hochman, who is also the Clinical Chief of the Leon H. Charney Division of Cardiology and the Harold Snyder Family Professor of Cardiology at NYU School of Medicine. "We thought it was possible that the risk of a recurrent heart attack would also be reduced. The results were surprising and do warrant a major change in practice."

"Angioplasty has been proven to improve symptoms in patients with angina and to prolong life in patients early after a heart attack," said Dr. Hochman. "This study shows that angioplasty provides no benefit in these patients with a total blockage and no or mild symptoms late after a heart attack. Patients should know whether a procedure is being performed to treat symptoms or whether there is evidence that they will live longer or have a lower likelihood of heart attack or heart failure," she said.

Interventional cardiologists use miniature devices that clear clogged arteries and restore blood flow to the heart to treat heart attack patients. In the study, doctors employed balloon angioplasty, which flattens plaque against the walls of blood vessels by inflating a tiny balloon tethered to the tip of a catheter. Tiny wire tubes called stents were inserted then into the artery to keep the vessel open. The vast majority of the patients who were treated with the balloon procedure had stents implanted at the same time.

"It is critical that patients present immediately after the onset of symptoms of a heart attack," said Dr. Hochman. "If they miss the reperfusion treatment window, they should receive optimal medication therapy. Medical therapy has improved dramatically and those patients did quiet well and better than projected."

A trial on five continents

The OAT study involved 217 sites on five continents. It enrolled 2,166 patients who had a completely blocked coronary artery causing their heart attack, which was identified after the early phase of the heart attack. All of the patients were in stable condition. They were randomly assigned by computer to receive balloon angioplasty and stents plus medical therapy or medical therapy alone three to 28 days after their heart attack. Researchers tracked their health for an average of three years after the heart attack.

There was no statistically significant difference between the two groups in the occurrence of death, heart attacks, or heart failure in up to five years of follow up, according to the study. The researchers also observed a "worrisome" trend toward excess rates of repeat heart attack in the group receiving the angioplasty and stents. Dr. Hochman said that further analysis and longer follow up is necessary to understand this observation, which did not reach the level of statistical significance, so it could have been due to chance alone.

Dr. Hochman speculated that opening a totally blocked artery in a patient who has collateral blood flow may interfere with the ability of the collateral vessels to rapidly supply blood if the opened (stented) artery re-closes. "It seems that total occlusion is a stable situation and this may be converted to a potential risk for recurrent heart attack if the artery is opened and then re-occludes," she said. In addition, it is possible that some heart muscle may be damaged due to dislodging of clots and plaque at the time of the angioplasty procedure, counteracting other potential long-term benefits.

Jennifer Choi | EurekAlert!
Further information:
http://www.nyumc.org

More articles from Health and Medicine:

nachricht Study suggests possible new target for treating and preventing Alzheimer's
02.12.2016 | Oregon Health & Science University

nachricht The first analysis of Ewing's sarcoma methyloma opens doors to new treatments
01.12.2016 | IDIBELL-Bellvitge Biomedical Research Institute

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: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>