(Press-News.org) The temporary placement of umbrella-like, metal mesh filters in abdominal veins to stop potentially lethal blood clots from traveling to the lungs during and after weight loss surgery may actually increase the risk of death in morbidly obese patients, according to new Johns Hopkins research.
The study's findings, reported in the journal JAMA Surgery, suggest that more tried-and-true measures to prevent venous thromboembolism (VTE) and its deadlier cousin pulmonary embolism (PE) — such as a standard prophylactic dose of blood thinners, early ambulation, and use of leg compression devices — are best in these patients.
The researchers also found that higher doses of blood thinners in obese patients, a group at higher risk for developing clots, were no more effective than standard doses given to patients who weigh less.
"If you're undergoing minimally invasive bariatric surgery, receive standard doses of blood thinners and get up and about as soon as possible after your operation, the chances of getting a blood clot are low," says study leader Daniel J. Brotman, M.D., an associate professor of medicine at the Johns Hopkins University School of Medicine and director of the hospitalist program at The Johns Hopkins Hospital. "And the evidence suggests that use of filters may do more harm than good."
The placement of filters in the inferior vena cava, the large vein that carries blood from the lower parts of the body to the heart, have become more common in surgery since they no longer need to be implanted permanently, like stents used to open clogged coronary arteries. The filters can be removed after the risk of clots has passed. Patients who are obese and patients who have just undergone surgery are two categories of people at increased risk for developing potentially deadly clots, statistics show.
The filters are supposed to act as a physical barrier to keep clots that form in leg veins from breaking off and reaching the heart and lungs. They may still be indicated for some patients who are at increased bleeding risk and therefore cannot tolerate blood thinners.
The researchers reviewed previously published medical literature on the comparative effectiveness and safety of pharmacological and mechanical strategies to prevent VTE in bariatric patients. Then they reanalyzed the data from eight pharmacologic studies and five studies of filter placement. Comparing outcomes, they found that filters did not reduce the risk of deadly lung clots, and saw some evidence that they are associated with higher overall mortality in the patients.
"If filters helped, we could find no evidence of that," Brotman says. "The data suggest more patients are harmed than benefit from these devices."
Brotman says the risk of fatal blood clots in bariatric surgery patients is less than 1 percent. One reason may be that the operation is becoming less invasive, allowing patients to get up and walk around sooner after surgery, another way to prevent blood clots from forming, he says.
The Johns Hopkins team's analysis suggests that increasing blood thinner doses based on weight made no obvious difference in whether bariatric surgery patients developed clots. "I was a bit surprised by this, since we do use higher doses of blood thinning medications in larger patients when we're treating clots, so one would think that larger patients would also require higher doses of these medications to prevent clots," says Brotman. "But if this was the case, we could not detect it."
INFORMATION:
The research was funded by the Agency for Healthcare Research and Quality (HHSA-290-2007-10061 I) and is part of the "Comparative Effectiveness of Pharmacologic and Mechanical Prophylaxis of Venous Thromboembolism Among Special Populations" report which looks at VTE prevention in subgroups such as trauma patients, elderly patients and burn patients.
Other Johns Hopkins researchers include Hasan M. Shihab, M.B.Ch.B., M.P.H.; Kaplana R. Prakasa, M.B.B.S., M.S.; Sosena Kebede, M.D., M.P.H.; Elliott R. Haut, M.D.; Ritu Sharma, B.Sc.; Kenneth Shermock, Pharm.D., Ph.D.; Yohalakshmi Chelladurai, M.B.B.S., M.P.H.; Sonal Singh, M.D., M.P.H.; and Jodi B. Segal, M.D., M.P.H.
Media Contact: Stephanie Desmon
410-955-8665; sdesmon1@jhmi.edu
Helen Jones
410-502-9422; hjones49@jhmi.edu
END
In a study published today in the journal PLOS ONE, a team of researchers led by NJIT Associate Professor Gareth Russell has applied a novel method for linking large-scale habitat fragmentation to population sustainability.
"Our goal was to assess the extinction risk for bird species in the Atlantic Forest of Brazil, a global 'hotspot' of bird diversity," said Russell. "Based on elevation restrictions and forest type requirements, as well as ongoing tropical deforestation, we already knew that most species have access to far less habitat than typically assumed. But ...
PHILADELPHIA – Researchers at the Perelman School of Medicine, University of Pennsylvania have developed a new gene therapy to thwart a potential influenza pandemic. Specifically, investigators in the Gene Therapy Program, Department of Pathology and Laboratory Medicine, directed by James M. Wilson, MD, PhD, demonstrated that a single dose of an adeno-associated virus (AAV) expressing a broadly neutralizing flu antibody into the nasal passages of mice and ferrets gives them complete protection and substantial reductions in flu replication when exposed to lethal strains ...
Contact: Anita Srikameswaran
Phone: 412-578-9193
E-mail: SrikamAV@upmc.edu
Contact: Susan Manko
Phone: 412-586-9771
E-mail: MankoSM@upmc.edu END ...
CHAMPAIGN, Ill. — Researchers report that they have determined the precise chemical structure of the HIV capsid, a protein shell that protects the virus's genetic material and is a key to its virulence. The capsid has become an attractive target for the development of new antiretroviral drugs.
The report appears as the cover article in the journal Nature.
Scientists have long sought to understand how the HIV capsid is constructed, and many studies have chipped away at its mystery. Researchers have used a variety of laboratory techniques – cryo-electron microscopy, cryo-EM ...
Chevy Chase, MD—Practicing a form of meditation and stretching can help relieve symptoms of post-traumatic stress disorder and normalize stress hormone levels, according to a recent study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).
More than 7 million adults nationwide are diagnosed with post-traumatic stress disorder (PTSD) in a typical year. The mental health condition, triggered by a traumatic event, can cause flashbacks, anxiety and other symptoms.
PTSD patients have high levels of corticotrophin-releasing ...
Chevy Chase, MD—Levels of a biomarker in a pregnant woman's blood can help physicians gauge her risk of developing gestational diabetes during the first trimester, according to a recent study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).
Gestational diabetes is a form of diabetes that can develop during pregnancy, often during the second trimester. The condition causes glucose levels in the bloodstream to be higher than normal. Early diagnosis and treatment can help the woman manage the condition. If left untreated, ...
Chevy Chase, MD—Pregnant women who have thyroid disorders face greater risk of preterm birth and other complications that have short- and long-term consequences for the health of mother and child, according to a recent study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).
The risk of complications is heightened for both women who have underactive thyroid glands – a condition known as hypothyroidism – and those with overactive thyroid glands, or hyperthyroidism. Up to four percent of all pregnancies involve mothers ...
The way in which stars evolve and end their lives was for many years considered to be well understood. Detailed computer models predicted that stars of a similar mass to the Sun would have a period towards the ends of their lives -- called the asymptotic giant branch, or AGB [1] -- when they undergo a final burst of nuclear burning and puff off a lot of their mass in the form of gas and dust.
This expelled material [2] goes on to form the next generations of stars and this cycle of mass loss and rebirth is vital to explain the evolving chemistry of the Universe. This ...
The physics behind some of the most extraordinary stellar objects in the Universe just became even more puzzling.
A group of astronomers led by McGill researchers using NASA's Swift satellite have discovered a new kind of glitch in the cosmos, specifically in the rotation of a neutron star.
Neutron stars are among the densest objects in the observable universe; higher densities are found only in their close cousins, black holes. A typical neutron star packs as much mass as half-a-million Earths within a diameter of only about 20 kilometers. A teaspoonful of neutron ...
Astrophysicists have found that contrary to decades of orthodoxy, stars with a high sodium content die before reaching the final, spectacular stages of life.
In a study published today in Nature, an international group of researchers led by Dr Simon Campbell of the Monash Centre for Astrophysics (MoCA), used the European Southern Observatory's 'Very Large Telescope' (VLT) to observe NGC 6752, a globular cluster of stars in our galaxy, 13,000 light years from Earth.
They found that 70 per cent of stars in the tightly bound group fail to reach the final red giant phase. ...
