Using Blood Pressure Cuff Right Before Heart Surgery Cuts Heart Damage: Study

Inflating a blood pressure cuff on a patient's upper arm just before heart bypass surgery reduces heart damage and may improve long-term survival, according to a new study.

This practice, called "remote ischemic preconditioning," involves using the blood pressure cuff to briefly cut off, and then restore, blood supply to an area of the body distant from the heart, such as the arm.

The study appears in the Aug. 17 issue of The Lancet.

Heart muscle damage is a common consequence of complex heart procedures such as bypass surgery and is associated with poorer long-term survival and health problems such as heart attack, according to a journal news release.

This study included 162 patients who had remote ischemic preconditioning before heart bypass surgery. A blood pressure cuff was inflated on their left upper arm, restricting blood supply for five minutes, followed by five minutes of normal blood flow. This was repeated three times.

These patients were compared to a control group of 167 patients who did not undergo the procedure before heart bypass surgery.

Following surgery, the researchers measured the patients' blood concentrations of troponin I, a protein that indicates heart muscle damage. Higher concentrations indicate more damage. Seventy-two hours after surgery, troponin levels were an average of 17 percent lower among patients who had remote ischemic conditioning than among those in the control group.

The researchers also followed patients for up to four years to determine if remote preconditioning had any effect on long-term health. One year after surgery, patients who had remote ischemic preconditioning were 73 percent less likely to have died of any cause, and 86 percent less likely to have died from heart attack or stroke, compared to those in the control group.

"The results of our study are very encouraging that remote ischemic preconditioning not only reduces heart muscle injury but also improves long-term health outcomes for heart bypass patients, and we hope that these benefits will be confirmed in larger prospective studies which are currently taking place," study co-leader Professor Gerd Heusch, of the University School of Medicine Essen in Germany, said in the news release.

Dr. Matthias Thielmann, also of the University School of Medicine Essen, said remote ischemic preconditioning is noninvasive, cheap and safe. "This procedure could be a promising and simple strategy to protect patients' heart muscle during surgery and hopefully improve health outcomes after surgery," he said in the news release.

SOURCE: The Lancet, news release, Aug. 15, 2013

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Alzheimer's Research Takes a New Turn

Study suggests that gummed-up synapses -- not plaque -- may be at the root of aging brain diseases

A protein that accumulates in healthy aging brains could prove to be the culprit behind the natural forgetfulness that comes with growing old as well as advanced neurodegenerative diseases such as Alzheimer's, according to a new study.

The protein, known as C1q, accumulates on the brain's synapses as people age, potentially gumming up the works, said Dr. Ben Barres, professor and chair of neurobiology at the Stanford University School of Medicine and senior author of the study, published Aug. 14 in the Journal of Neuroscience.

A post-mortem review of mouse and human brains found that the amount of C1q in the brain increases as much as 300-fold with aging.

By comparing brain tissue from mice of varying ages as well as postmortem samples from a 2-month-old infant and an older person, the researchers found that the growing C1q deposits weren't randomly distributed along nerve cells.

Instead, they heavily concentrate at synapses (the junctions between nerve cells), where they could hamper the conduction of electrical and chemical signals in the brain.

"Synapses are not being lost," Barres said. "However, we see the synapses aren't working so good with all that C1q stuck to them. It's detrimental."

But C1q is known to play an important part in the developing brain during childhood, and Barres suspects that this function could lead the protein to attack the synapses if triggered. Such an attack could be the cause of Alzheimer's disease and other neurodegenerative disorders.

This hypothesis runs counter to prevailing theories about Alzheimer's, which have focused on the accumulation of amyloid plaques in the brain as a cause of the disease.

In a normal developing brain, synapses are both created and destroyed -- a process Barres likens to "pruning" the brain by preserving necessary synapses and eliminating the excess.

"What wasn't clear is what the molecular basis of the synapse pruning was," Barres said. "It involves a normal immune protein that people didn't even realize was in the brain -- C1q."

C1q is capable of clinging to the surface of foreign bodies such as bacteria or to bits of dead or dying human cells. This initiates a molecular chain reaction known as the complement cascade. One by one, the system's other proteins glom on, coating the offending cell or piece of debris. This in turn draws the attention of omnivorous immune cells that gobble up the target.

Barres now hypothesizes that diseases such as Alzheimer's might develop if the C1q that has accumulated on the synapses triggers an immune system attack against them.

"The first regions of the brain to show a dramatic increase in C1q are places like the hippocampus and substantia nigra, the precise brain regions most vulnerable to neurodegenerative diseases like Alzheimer's and Parkinson's disease, respectively," Barres said. Another region affected early on, the piriform cortex, is associated with the sense of smell, whose loss often heralds the onset of neurodegenerative disease.

"Our findings may well explain the long-mysterious vulnerability specifically of the aging brain to neurodegenerative disease," he said. "Kids don't get Alzheimer's or Parkinson's," Barres pointed out.

"Profound activation of the complement cascade, associated with massive synapse loss, is the cardinal feature of Alzheimer's disease and many other neurodegenerative disorders. People have thought this was because synapse loss triggers inflammation. But our findings here suggest that activation of the complement cascade is driving synapse loss, not the other way around," Barres explained.

Heather Snyder, director of medical and scientific operations for the Alzheimer's Association, said the new study "adds to the body of information that looks at how the immune system might work in Alzheimer's disease." She added that there are many hypotheses that need to be explored about what may be happening in Alzheimer's.

Noting that much of the research in the current study involved mice, Snyder said future studies need to focus on how C1q affects human brains.

"This is really opening the door that this should be explored further," she said. "It needs to be replicated in the laboratory and also correlated to what it may mean in human beings."

More than 5 million Americans have Alzheimer's disease, and that number is expected to rise significantly as the baby boom generation ages.

SOURCES: Ben Barres, M.D., Ph.D., professor and chair, neurobiology, Stanford University School of Medicine, Stanford, Calif.; Heather Snyder, director, medical and scientific operations, Alzheimer's Association; Aug. 14, 2013, Journal of Neuroscience

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Breastfeeding could be good not only for the baby but also for the mother

Could breastfeeding be as good for a Mom's health as it is for her babies? A new study in the Journal of Clinical Nursing looks at the relationship between breast cancer and certain features of pregnancy and breastfeeding.

The researchers collected data from the medical records of more than 500 women who were diagnosed with breast cancer from 2004 to 2009. The women were 19 to 91 years of age. The team looked at age of diagnosis, how long the women breastfed, family history of cancer, obesity, alcohol consumption and smoking habits.

The results: women who breastfed were diagnosed with breast cancer at a later age, regardless of family history.

Nonsmokers who breastfed for more than six months were diagnosed much later in life - an average 10 years later than nonsmokers who breastfed for a shorter period.

Smokers, on the other hand, were diagnosed with breast cancer at a younger age and saw no significant benefit from longer breastfeeding.

The researchers say their findings show that longer breastfeeding is not only beneficial for children, but may protect mothers against the serious disease like breast cancer.

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Ruling Out Unneeded Ankle X-Rays for Kids

Applying simple rule for low-risk injuries helped ER docs cut use by 22 percent

By using a simple rule to assess children's ankle injuries, doctors could reduce the use of X-rays by 22 percent -- and so spare kids unneeded radiation exposure, according to a new study.

The research appears in the current issue of the CMAJ (Canadian Medical Association Journal). While X-rays are used to diagnose 85 percent to 95 percent of ankle injuries in children, only 12 percent of X-rays show fractures, according to a journal news release.

"Radiography is unnecessary for most children's ankle injuries, and these high rates of radiography needlessly expose children to radiation and are a questionable use of resources," wrote Dr. Kathy Boutis, a pediatric emergency department physician at the Hospital for Sick Children and the University of Toronto, and colleagues.

The investigators applied the "low risk ankle rule" in more than 2,100 children, aged 3 to 16, who arrived at six Canadian emergency departments with non-penetrating ankle injuries.

The rule states that if an examination of a child's injured ankle suggests that there is a low risk of fracture, an X-ray may not be necessary. If doctors miss a certain category of fractures, evidence shows that they are stable, pose a low risk for any future problems, and can be treated like an ankle sprain.

The 22 percent reduction in the use of X-rays when using the rule was consistent in the different emergency departments.

"The ankle rule has potential broad applicability to emergency departments throughout most of the developed world, and widespread implementation of this rule could safely lead to reduction of unnecessary radiography in this radiosensitive population and a more efficient use of health care resources," the researchers concluded.

SOURCE: CMAJ (Canadian Medical Association Journal), news release, Aug. 12, 2013

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