Heart repair breakthroughs replace surgeon’s knife

Heart care is in the midst of a transformation. Many problems that once required sawing through the breastbone and opening up the chest for open heart surgery now can be treated with a nip, twist or patch through a tube.
These minimal procedures used to be done just to unclog arteries and correct less common heart rhythm problems. Now some patients are getting such repairs for valves, irregular heartbeats, holes in the heart and other defects?without major surgery. Doctors even are testing ways to treat high blood pressure with some of these new approaches.

All rely on catheters?hollow tubes that let doctors burn away and reshape heart tissue or correct defects through small holes into blood vessels.

“This is the replacement for the surgeon’s knife. Instead of opening the chest, we’re able to put catheters in through the leg, sometimes through the arm,” said Dr. Spencer King of St. Joseph’s Heart and Vascular Institute in Atlanta. He is former president of the American College of Cardiology. Its conference earlier this month featured research on these novel devices.

“Many patients after having this kind of procedure in a day or two can go home” rather than staying in the hospital while a big wound heals, he said. It may lead to cheaper treatment, although the initial cost of the novel devices often offsets the savings from shorter hospital stays.

Not everyone can have catheter treatment, and some promising devices have hit snags in testing. Others on the market now are so new that it will take several years to see if their results last as long as the benefits from surgery do.

But already, these procedures have allowed many people too old or frail for an operation to get help for problems that otherwise would likely kill them.

“You can do these on 90-year-old patients,” King said.

These methods also offer an option for people who cannot tolerate long-term use of blood thinners or other drugs to manage their conditions, or who don’t get enough help from these medicines and are getting worse. “It’s opened up a whole new field,” said Dr. Hadley Wilson, cardiology chief at Carolinas HealthCare System in Charlotte. “We can hopefully treat more patients more definitively, with better results.” For patients, this is crucial: Make sure you are evaluated by a “heart team” that includes a surgeon as well as other specialists who do less invasive treatments. Many patients now get whatever treatment is offered by whatever specialist they are sent to, and those specialists sometimes are rivals. “We want to get away from that” and do whatever is best for the patient, said Dr. Timothy Gardner, a surgeon at Christiana Care Health System in Newark, Delaware, and an American Heart Association spokesman. “There shouldn’t be a rivalry in the field.” Here are some common problems and newer treatments for them:

Heart valves

illions of people have leaky heart valves. Each year, more than 100,000 people in the United States alone have surgery for them. A common one is the aortic valve, the heart’s main gate. It can stiffen and narrow, making the heart strain to push blood through it. Without a valve replacement operation, half of these patients die within two years, yet many are too weak to have one. “Essentially, this was a death sentence,” said Dr. John Harold, a Los Angeles heart specialist who is president of the College of Cardiology. That changed just over a year ago, when Edwards Lifesciences Corp. won approval to sell an artificial aortic valve flexible and small enough to fit into a catheter and be wedged inside the bad one. At first it was just for inoperable patients. Last fall, use was expanded to include people able to have surgery but at high risk of complications. Gary Verwer, 76, of Napa, California, had a bypass operation in 1988 that made surgery too risky when he later developed trouble with his aortic valve. “It was getting worse every day. I couldn’t walk from my bed to my bathroom without having to sit down and rest,” he said. After getting a new valve through a catheter last April at Stanford University, “everything changed; it was almost immediate,” he said. “Now I can walk almost three miles a day and enjoy it. I’m not tired at all.” “The chest cracking part is not the most fun,” he said of his earlier bypass surgery. “It was a great relief not to have to go through that recovery again.” Catheter-based treatments for other valves also are in testing. One for the mitral valve?Abbott Laboratories’ MitraClip?had a mixed review by federal Food and Drug Administration advisers this week; whether it will win FDA approval is unclear. It is already sold in Europe.

Heart rhythm problems

Catheters can contain tools to vaporize or “ablate” bits of heart tissue that cause abnormal signals that control the heartbeat. This used to be done only for some serious or relatively rare problems, or surgically if a patient was having an operation for another heart issue. Now catheter ablation is being used for the most common rhythm problem?atrial fibrillation, which plagues about 3 million Americans and 15 million people worldwide. The upper chambers of the heart quiver or beat too fast or too slow. That lets blood pool in a small pouch off one of these chambers. Clots can form in the pouch and travel to the brain, causing a stroke. Ablation addresses the underlying rhythm problem. To address the stroke risk from pooled blood, several novel devices aim to plug or seal off the pouch. Only one has approval in the U.S. now?SentreHeart Inc.’s Lariat, a tiny lasso to cinch the pouch shut. It uses two catheters that act like chopsticks. One goes through a blood vessel and into the pouch to help guide placement of the device, which is contained in a second catheter poked under the ribs to the outside of the heart. A loop is released to circle the top of the pouch where it meets the heart, sealing off the pouch. A different kind of device?Boston Scientific Corp.’s Watchman?is sold in Europe and parts of Asia, but is pending before the FDA in the U.S. It’s like a tiny umbrella pushed through a vein and then opened inside the heart to plug the troublesome pouch. Early results from a pivotal study released by the company suggested it would miss a key goal, making its future in the U.S. uncertain.

Heart defects

Some people have a hole in a heart wall called an atrial septal defect that causes abnormal blood flow. St. Jude Medical Inc.’s Amplatzer is a fabric-mesh patch threaded through catheters to plug the hole. The patch is also being tested for a more common defect?PFO, a hole that results when the heart wall doesn’t seal the way it should after birth. This can raise the risk of stroke. In two new studies, the device did not meet the main goal of lowering the risk of repeat strokes in people who had already suffered one, but some doctors were encouraged by other results.

?logged arteries

The original catheter-based treatment?balloon angioplasty?is still used hundreds of thousands of times each year in the U.S. alone. A Japanese company, Terumo Corp., is one of the leaders of a new way to do it that is easier on patients?through a catheter in the arm rather than the groin. Newer stents that prop arteries open and then dissolve over time, aimed at reducing the risk of blood clots, also are in late-stage testing.

High blood pressure

About 75 million Americans and 1 billion people worldwide have high blood pressure, a major risk factor for heart attacks. Researchers are testing a possible long-term fix for dangerously high pressure that can’t be controlled with multiple medications. It uses a catheter and radio waves to zap nerves, located near the kidneys, which fuel high blood pressure. At least one device is approved in Europe and several companies are testing devices in the United States. “We’re very excited about this,” said Harold, the cardiology college’s president. It offers hope to “essentially cure high blood pressure.” Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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CT scans find clogged arteries in mummies

“We found that heart disease is a serial killer that has been stalking mankind for thousands of years,” says researcher Gregory Thomas. “In the last century, atherosclerotic vascular disease has replaced infectious disease as the leading cause of death across the developed world.”

The researchers performed CT scans of 137 mummies from across four continents and found artery plaque in every single population studied, from preagricultural hunter-gatherers in the Aleutian Islands to the ancient Puebloans of southwestern United States.

Their findings provide an important twist to one?s understanding of atherosclerotic vascular disease, which is the leading cause of death in the developed world: While modern lifestyles can accelerate the development of plaque on arteries, the prevalence of the disease across human history shows it may have a more basic connection to inflammation and aging.

?This is not a disease only of modern circumstance but a basic feature of human aging in all populations,? says Professor Caleb Finch of University of Southern California (USC), a senior author of the study.

?Turns out even a Bronze Age guy from 5,000 years ago had calcified, carotid arteries,? Finch says, referring to Ötzi the Iceman, a natural mummy who lived around 3200 B.C. and was discovered frozen in a glacier in the Italian Alps in 1991.

With Gregory Thomas of Long Beach Memorial, Finch was part of a team that previously showed Egyptian mummies had calcified patches on their arteries indicative of advanced atherosclerosis (from the Greek ?athero,? meaning ?gruel,? and ?scler,? meaning ?hard?).

But ancient Egyptians tended to mummify only royalty or those who had privileged lives. The new study led by Thomas and Randall Thompson of Saint Luke?s Mid America Heart Institute examined mummies from four drastically different climates and diets?and from cultures that mummified regular people, including ancient Peruvians, Ancestral Puebloans, the Unangans of the Aleutian Islands, and ancient Egyptians.

?Our research shows that we are all at risk for atherosclerosis, the disease that causes heart attacks and strokes?all races, diets, and lifestyles,? says Thomas.

?Because of this we all need to be cautious of our diet, weight, and exercise to minimize its impact. The data gathered about individuals from the prehistoric cultures of ancient Peru and the Native Americans living along the Colorado River and the Unangan of the Aleutian Islands is forcing us to think outside the box and look for other factors that may cause heart disease.?

Overall, the researchers found probable or definite atherosclerosis in 34 percent of the mummies studied, with calcification of arteries more pronounced in the mummies that were older at the time of death. Atherosclerosis was equally common in mummies identified as male or female.

?We found that heart disease is a serial killer that has been stalking mankind for thousands of years,? Thompson says. ?In the last century, atherosclerotic vascular disease has replaced infectious disease as the leading cause of death across the developed world.

?A common assumption is that the rise in levels of atherosclerosis is predominantly lifestyle-related, and that if modern humans could emulate preindustrial or even preagricultural lifestyles, that atherosclerosis, or at least its clinical manifestations, would be avoided.

?Our findings seem to cast doubt on that assumption, and at the very least, we think they suggest that our understanding of the causes of atherosclerosis is incomplete and that it might be somehow inherent to the process of human aging,? he adds.

The researchers will next seek to biopsy ancient mummies to get a better understanding of the role chronic infection, inflammation, and genetics play in promoting the prevalence of atherosclerosis.

?Atherosclerosis starts very early in life. In the United States, most kids have little bumps on their arteries. Even stillbirths have little tiny nests of inflammatory cells. But environmental factors can accelerate this process,? Finch says, pointing to studies that show larger plaque buildup in children exposed to household tobacco smoking or who are obese.

Source: University of Southern California

Infant brain controls blood flow differently

?The control of blood flow in the brain is very important,? says Elizabeth Hillman, associate professor of biomedical engineering and of radiology, who led the research study in her Laboratory for Functional Optical Imaging at Columbia University.

?Not only are regionally specific increases in blood flow necessary for normal brain function, but these blood-flow increases form the basis of signals measured in fMRI, a critical imaging tool used widely in adults and children to assess brain function,? says Hillman. ?Many prior fMRI studies have overlooked the possibility that the infant brain controls blood flow differently.?

Functional magnetic resonance imaging, or fMRI, is one of several brain-imaging methods that measure changes in blood flow to detect the presence and location of neuronal activity. In adults, blood-flow increases occur in specific regions of the brain during a particular task like moving your hand or reacting to a stimulus.

?We found that the immature brain does not generate localized blood-flow increases in response to stimuli,? says Mariel Kozberg, a neurobiology MD-PhD candidate and lead author of the paper published in the Proceedings of the National Academy of Sciences. ?By tracking changes in blood-flow control with increasing age, we observed the brain gradually developing its ability to increase local blood flow and, by adulthood, generate a large blood-flow response.?

Hillman says the findings suggest that vascular development may be an important new factor to consider in normal and abnormal brain development.

The team used a unique high-speed, high-resolution imaging approach that takes advantage of the different absorption spectra of deoxygenated and oxygenated hemoglobin in order to determine changes in the concentrations of each.

The researchers found that, with increasing age, there was a gradual development of a localized increase in blood flow, while a strong, delayed decrease in flow was consistently present. Only by adulthood was the positive increase able to balance the decrease in flow.

?Our results suggest that the infant brain might not be able to generate localized blood-flow increases, even if there is neuronal activity occurring, and that the development of blood-flow control occurs in parallel with early neuronal development,? says Kozberg.

?This could suggest that fMRI studies of infants and children may be detecting changes in both vascular and neuronal development?in fact, vascular development may be an important new factor to consider in normal and abnormal brain development.?

The team also found that the younger age groups were highly sensitive to blood pressure increases in response to stimulation and that these increases can cause large increases in blood flow across the brain.

?This finding indicates that the newborn brain is also unable to regulate its overall blood-flow levels,? Kozberg explains. ?This could explain earlier fMRI results in infants and children that were sometimes positive and sometimes negative, because it is difficult to tell whether blood pressure increases are occurring in infants and children. This result suggests that great care should be taken in setting stimulus thresholds in young subjects.?

The researchers add that, since the newborn brain appears to be able to sustain itself without tightly controlled blood flow, their findings suggest that the infant brain may be intrinsically more resistant to damage due to a lack of oxygen than the adult brain.

?This could be an important property to understand, both in terms of understanding how best to treat blood-flow problems in the newborn infant brain, which can cause lifelong problems such as cerebral palsy, and to potentially better understand how to treat the adult brain in conditions such as stroke,? Hillman observes.

This research was supported by grants and student fellowships from the National Institute of Neurological Disorders and Stroke, the National Eye Institute, the National Science Foundation, the National Defense Science and Engineering Graduate Fellowship, the Medical Scientist Training Program, and the Human Frontier Science Program.

Source, Columbia University