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Cardiovascular Medicine, Chronic Disease, In the News, Research, Science, Stanford News

How best to treat dialysis patients with heart disease

How best to treat dialysis patients with heart disease

523392_4923732760_zKidney failure patients on dialysis often have other chronic diseases – heart disease topping the list. They’re prescribed an average of 12 pills a day by physicians, according to Stanford nephrologist Tara Chang, MD, and they spend three-to-four hours at a treatment center three times a week connected to an artificial kidney machine.

For Chang, this makes it all the more important that any medication she prescribes for a patient on dialysis is both essential and effective.

The problem is, particularly in the case of treating kidney patients with heart disease, evidence-based treatment guidelines just aren’t available. Kidney doctors are left making best guesses based on guidelines written for the general population.

“Our patients might be different from patients not on dialysis,” said Chang. “Dialysis patients have a lot of heart disease, yet rarely does a cardiology study enroll patients on dialysis, so we just don’t know.”

This was part of the motivation behind Chang’s most recent study examining the use of anti-platelet drugs such as clopidogrel, one of the most commonly prescribed drugs for kidney patients. The researchers looked at the use of anti-platelet medications such as clopidogrel as treatment following stenting procedures to unclog arteries in the heart in 8,458 dialysis patients between 2007 and 2010. The data suggests that longer-duration of drug use may be of benefit to patients on dialysis who get drug-eluding stents but not those who get bare metal stents. Chang told me:

We found that for those who got drug-eluting stents who took the drug for 12 months compared to those who had stopped the drug at some earlier time point, there was a non-statistically significant trend towards lower risks of death and heart attacks. So for this group, following the same guidelines as for the general population may be appropriate. However, we found no indication of benefit with longer duration of anti-platelet drug use for patients on dialysis who got bare metal stents.

About half of the 400,000 patients in the U.S. on dialysis also have coronary artery disease, as referenced in the study. The number of those getting stents inserted to unclog arteries also has increased 50 percent in the past decade, the study states. The results of the study, while not definitive as to exactly how long doctors should prescribe the drug, does stress the need for more clinical research on patients with kidney failure to provide guidance on treatment strategies for heart disease.

“Because our study was not a randomized trial,” said Chang, “we tried to be very measured in how we interpreted the results. What it does point to is the fact that we can’t assume that what works in non-dialysis patients works in dialysis patients. Hopefully our study will help convince researchers to include our dialysis patients in their studies.”

The paper was published this week in the Journal of the American Heart Association.

Previously: Keeping kidney failure patients out of the hospitalStudy shows higher rates of untreated kidney disease among older adults and Study shows daily dialysis may boost patients’ heart function, physical health.
Photo by newslighter

Cardiovascular Medicine, Men's Health, Mental Health, Research, Women's Health

Examining how mental stress on the heart affects men and women differently

Examining how mental stress on the heart affects men and women differently

stress_womanPast research has shown that stress, anger and depression can increase a person’s risk for stroke and heart attacks. Now new findings published in the Journal of the American College of Cardiology show that cardiovascular and psychological reactions to mental stress vary based on gender.

In the study (subscription required), participants with heart disease completed three mentally stressful tasks. Researchers monitored changes in their heart using echocardiography, measured blood pressure and heart rate, and took blood samples during the test and rest periods. According to a journal release:

Researchers from the Duke Heart Center found that while men had more changes in blood pressure and heart rate in response to the mental stress, more women experienced myocardial ischemia, decreased blood flow to the heart. Women also experienced increased platelet aggregation, which is the start of the formation of blood clots, more than men. The women compared with men also expressed a greater increase in negative emotions and a greater decrease in positive emotions during the mental stress tests.

“The relationship between mental stress and cardiovascular disease is well known,” said the study lead author Zainab Samad, M.D., M.H.S., assistant professor of medicine at Duke University Medical Center, Durham, North Carolina. “This study revealed that mental stress affects the cardiovascular health of men and women differently. We need to recognize this difference when evaluating and treating patients for cardiovascular disease.”

Previously: Study shows link between traffic noise, heart attack, Ask Stanford Med: Cardiologist Jennifer Tremmel responds to questions on women’s heart health and Study offers insights into how depression may harm the heart
Photo by anna gutermuth

Cardiovascular Medicine, Events, Patient Care, Stanford News

A ssathi (partner) to thwart heart disease in South Asians

A ssathi (partner) to thwart heart disease in South Asians

heart-66892_1280S.S., a 44-year-old male South Asian engineer, visited Rajesh Dash, MD, PhD, at his Stanford clinic not long ago.

“He had come to see me almost as a third option,” Dash told a crowd of 25-or-so listeners at a presentation on South Asians and heart disease sponsored by the Stanford Health Library last week. Dash didn’t mention why S.S. originally visited a doctor. But he said S.S. exercised three times a week and ate relatively healthy food. He smoked socially. His blood pressure was only slightly elevated. He didn’t appear to be at high risk for heart disease.

One doctor had left S.S. with little more information than he had before the visit after the results of a standard diagnostic questionnaire were inconclusive. Another doctor recommended an angiogram. S.S. balked – why, he asked.

So he came to see Dash, who directs SSATHI, or the Stanford South Asian Translational Heart Initiative, a clinical program that specializes in coronary disease and insulin resistance in South Asians, which is defined to include people from India, Pakistan, Bangladesh, Nepal, Bhutan, Maldives and Sri Lanka.

Dash asked S.S. a question no one else had: What about your family? “Well,” S.S. responded, “my older brother, who is 46, had a heart attack recently. My mother has four stents in her arteries. Three of my mother’s brothers died of heart attacks before they were 60.”

Now, no medical degree was needed to see that S.S. was clearly at high risk for heart disease. Dash prescribed a coronary CT scan that revealed that one of S.S.’s heart vessels was 99 percent blocked. In other words, S.S. was a walking time bomb. Doctors treated his condition aggressively with a combination of drugs, surgery, recommended lifestyle changes and follow-up care.

S.S. had three questions for Dash: Why did this happen to me? How can I prevent it from happening again? And, how can I prevent it from happening to my children?

Dash doesn’t have the answers to all the questions — yet. But his SSATHI team (Ssathi also means companion or partner in Hindi) is working to figure them out – and to keep S.S. healthy for decades to come. The team surrounds patients with experts — cardiologists, nutritionists, surgeons and others. And they provide social-media tools and encourage around-the-clock commitments from patients. The program is no cake walk.

Dash also shared some startling statistics: More than half of all South Asians who suffer heart attacks get them before age 50. In California, South Asians have four times more heart attacks than other ethnic groups. South Asians also have a high rate of diabetes and heart disease is now the top cause of death in India, Dash said.

Ssathi hopes to treat South Asians of all ages, but they’re particularly looking for new patients from ages 20 to 55 because heart disease in South Asians begins at young ages. The SSATHI program is focusing South Asians in California, but Dash said they also plan to introduce programs in India.

Previously: Global community must do a better job of managing risk of Nipah virus, expert says, A closer look Asian American health and Gap exists in women’s knowledge of heart disease
Image by geralt

Cardiovascular Medicine, Genetics, Research, Science, Stanford News, Stem Cells

Stem cell study explains how mutation common in Asians affects heart health

Stem cell study explains how mutation common in Asians affects heart health

10011881004_d5ab6d7cd9_zMany Asians carry a mutation that causes their faces to flush when they drink alcohol. The affected gene is called ALDH2, and it also plays a role in cardiovascular health. Carriers are more susceptible to coronary artery disease and tend to recover more poorly than non-carriers from the damage caused by a heart attack. Now Stanford cardiologist Joseph Wu, MD, PhD, and postdoctoral scholar Antje Ebert, PhD, have learned why.

The researchers used a type of stem cell called an induced pluripotent stem cell, or iPS cell, to conduct the study. The stem cells are made from easily obtained tissue like skin, and they can be coaxed in the laboratory to become other types of tissue, like heart muscle cells. It’s one of the first times iPS cells have been used to examine ethnic-specific differences among populations. The research was published yesterday in Science Translational Medicine.

From our release:

The study showed that the ALDH2 mutation affects heart health by controlling the survival decisions cells make during times of stress. It is the first time ALDH2, which is involved in many common metabolic processes in cells of all types, has been shown to play a role in cell survival. In particular, ALDH2 activity, or the lack of it, influences whether a cell enters a state of programmed cell death called apoptosis in response to stressful growing conditions. [...]

The use of heart muscle cells derived from iPS cells has opened important doors for scientists because tissue samples can be easily obtained and maintained in the laboratory for study. Until recently, researchers had to confine their studies to genetically engineered mice or to human heart cells obtained through a heart biopsy, an invasive procedure that yields cells which are difficult to keep alive long term in the laboratory.

You’ve likely read about Wu’s previous work with heart muscle cells derived from iPS cells. Now he’s shown iPS cells are also a good way to compare the effect of genetic differences among populations, and he has big plans. More details about his plans from our release:

Wu is working to start a biobank at the Stanford Cardiovascular Institute of iPS cells from about 1,000 people of many different ethnic backgrounds and health histories. “This is one of my main priorities,” he said. “For example, in California, we boast one of the most diverse populations on Earth. We’d like to include male and female patients of major representative ethnicities, age ranges and cardiovascular histories. This will allow us to conduct ‘clinical trials in a dish’ on these cells, a very powerful new approach, to learn which therapies work best for each group. This would help physicians to understand for the first time disease process at a population level through observing these cells as surrogates.”

Previously: Induced pluripotent stem cell mysteries explored by Stanford researchers, A new era for stem cells in cardiac medicine? A simple, effective way to generate patient-specific heart muscle cells and “Clinical trial in a dish” may make common medicines safer, say Stanford scientists

Photo by Nicholas Raymond

Cardiovascular Medicine, Research, Science, Stanford News

Scientists preferentially cite successful studies, new research shows

Scientists preferentially cite successful studies, new research shows

Say you’re a medical researcher. You slave over a project for months, even years, and you’re thrilled when a stellar journal agrees to publish it. That’s it, right? Well, no. Now, you need others to spot your work – and cite it in their studies. You can court citations just as you court Twitter followers: by producing high-quality content worthy of a bigger audience.

That said, sometimes bias creeps in. For example, studies by superstar scientists are cited more often than those by their junior colleagues — no surprise there. But now, Stanford medical resident Alex Perino, MD; cardiologist Mintu Turakhia, MD, MAS; and colleagues have shown that studies documenting higher success rates of a certain procedure are more likely to be cited than studies of the same procedure with lower success rates.

“This is an indication that we as clinicians and investigators need to be mindful of how we present the data,” Turakhia told me.

In a study released yesterday in Circulation: Cardiovascular Quality and Outcomes, Perino, Turakhia and other colleagues examined research papers on catheter ablation for atrial fibrillation, a treatment with widely varying success rates. For example, among the examined studies, the success of a single treatment varied between 10 and 92 percent. The variation is perfectly understandable, Turakhia said. Atrial fibrillation, an irregular heart rhythm, can be caused by a variety of underlying conditions and can vary in severity, he explained. The procedure itself, which uses energy to destroy tissue in key areas of the left atrium, can also vary, Turakhia said.

That’s why ablation for atrial fibrillation was an apt treatment to examine. The team included 174 studies with 36,289 patients published since 1990. They found that for every 10 point increase in reported success rate, there was an 18 percent increase in the mean citation count. The citation bias remained significant even when accounting for time since publication, the journal’s impact rating, sample size and study design.

The bias is important when considering the efficacy of new and evolving treatments, Turakhia said: “We just wanted to make sure the totality of evidence is being presented fairly and completely to readers of the medical literature, which may be clinicians, scientists, insurance companies and policy makers. However, in this case, we found that ablation could be perceived to be more effective than the totality of evidence would suggest.”

Turakhia said he hopes this study prompts other researchers to examine bias in other treatments and specialties.

Previously: Re-analyses of clinical trial results rare, but necessary, say Stanford researchers, John Ioannidis discusses the popularity of his paper examining the reliability of scientific research, A discussion on the reliability of scientific research, U.S. effect leads to publication of biased research, says Stanford’s John Ioannidis

Cardiovascular Medicine, Patient Care, Pediatrics, Stanford News

A nurse puts heart into her work at Adult Congenital Heart Program

A nurse puts heart into her work at Adult Congenital Heart Program

heart_sillman_560A few decades ago, if a child was diagnosed a serious heart defect it was essentially a death sentence, but thanks to recent advances in neonatal heart surgery, most patients now live well into adulthood. And at least one of them has gone on to care for other people with congenital heart defects.

Christy Sillman, RN, is the nurse coordinator for Stanford’s Adult Congenital Heart Program and is profiled in the most recent issue of Inside Stanford Medicine. Although most people who were treated for heart defects as children don’t require continued surgical interventions as adults, doctors now know that they have other challenges that require ongoing care. Sillman went through this firsthand. After being told as a teenager that she was “cured” and going a decade without care, she learned she was suffering from cardiomyopathy, a deterioration of the heart muscle. From the article:

“At that point, my frustration with the medical care of people with congenital heart defects was elevated,” Sillman recalled. “I wouldn’t have been in such bad shape had I gotten the right care earlier. This motivated me to get more involved.”

That involvement was huge. Sillman talked with many people who shared similar stories, which inspired her to become an advocate for patients like herself. When a position was available with the program at Stanford in 2013, Sillman jumped at the chance and was hired.

“I don’t want any teenager to go through what I went through,” Sillman said. “Being told you’re cured and finding out that’s not really true? That should never happen.”

Sillman’s personal experiences are not unusual for a congenital cardiac patient of her generation, but it influenced her professional choices and now, she says, she enjoys bringing “a patient’s perspective” to her work.

Previously: Patient is “living to live instead of living to survive,” thanks to heart repair surgery
Photo by Norbert von der Groeben

Bioengineering, Cardiovascular Medicine, Neuroscience, Research, Stanford News, Stroke

Targeted stimulation of specific brain cells boosts stroke recovery in mice

big blue brainThere are 525,949 minutes in a year. And every year, there are about 800,000 strokes in the United States – so, one stroke every 40 seconds. Aside from the infusion, within three or four hours of the stroke, of a costly biological substance called tissue plasminogen activator (whose benefit is less-than-perfectly established), no drugs have been shown to be effective in treating America’s largest single cause of neurologic disability and the world’s second-leading cause of death. (Even the workhorse post-stroke treatment, physical therapy, is far from a panacea.)

But a new study, led by Stanford neurosurgery pioneer Gary Steinberg and published in Proceedings of the National Academy of Sciences, may presage a better way to boost stroke recovery. In the study, Steinberg and his colleagues used a cutting-edge technology to directly stimulate movement-associated areas of the brains of mice that had suffered strokes.

Known as optogenetics – whose champion, Stanford psychiatrist and bioengineer Karl Deisseroth, co-authored the study – the light-driven method lets investigators pinpoint a specific set of nerve cells and stimulate only those cells. In contrast, the electrode-based brain stimulation devices now increasingly used for relieving symptoms of Parkinson’s disease, epilepsy and chronic pain also stimulate the cells’ near neighbors.

“We wanted to find out whether activating these nerve cells alone can contribute to recovery,” Steinberg told me.

As I wrote in a news release  about the study:

By several behavioral … and biochemical measures, the answer two weeks later was a strong yes. On one test of motor coordination, balance and muscular strength, the mice had to walk the length of a horizontal beam rotating on its axis, like a rotisserie spit. Stroke-impaired mice [in which the relevant brain region] was optogenetically stimulated did significantly better in how far they could walk along the beam without falling off and in the speed of their transit, compared with their unstimulated counterparts. The same treatment, applied to mice that had not suffered a stroke but whose brains had been … stimulated just as stroke-affected mice’s brains were, had no effect on either the distance they travelled along the rotating beam before falling off or how fast they walked. This suggests it was stimulation-induced repair of stroke damage, not the stimulation itself, yielding the improved motor ability.

Moreover, levels of some important natural substances called growth factors increased in a number of brain areas in  optogenetically stimulated but not unstimulated post-stroke mice. These factors are key to a number of nerve-cell repair processes. Interestingly, some of the increases occurred not only where stimulation took place but in equivalent areas on the opposite side of the brain, consistent with the idea that when we lose function on one side of the brain, the unaffected hemisphere can step in to help restore some of that lost function.

Translating these findings into human trials will mean not just brain surgery, but also gene therapy in order to introduce a critical light-sensitive protein into the targeted brain cells. Steinberg notes, though, that trials of gene therapy for other neurological disorders have already been conducted.

Previously: Brain sponge: Stroke treatment may extend time to prevent brain damage, BE FAST: Learn to recognize the signs of stroke and Light-switch seizure control? In a bright new study, researchers show how
Photo by Shutterstock.com

From August 11-25, Scope will be on a limited publishing schedule. During that time, you may also notice a delay in comment moderation. We’ll return to our regular schedule on August 25.

Cardiovascular Medicine, Health and Fitness, Medicine and Society, Research

Study questions safety of excessive exercise for heart attack survivors

Study questions safety of excessive exercise for heart attack survivors

Scope runningA recent article in PsychCentral highlighted findings published in the Mayo Clinic Proceedings offering more evidence that extreme exercise for heart attack survivors could put them at a higher risk for a cardiovascular event.

Paul Williams, PhD, staff scientist for the Life Sciences Division of Lawrence Berkeley National Laboratory, and Paul Thompson, MD, a cardiologist at Hartford Hospital, conducted a long-term study looking at the relationship between exercise and cardio-disease related death in about 2,400 physically-active heart attack survivors. The study reported on data taken from the National Walker’s and Runners’ heath studies at Lawrence Berkeley Laboratory.  From the piece:

“These analyses provide what is to our knowledge the first data in humans demonstrating a statistically significant increase in cardiovascular risk with the highest levels of exercise,” say Williams and Thompson.

“Results suggest that the benefits of running or walking do not accrue indefinitely and that above some level, perhaps 30 miles per week of running, there is a significant increase in risk.

Competitive running events also appear to increase the risk of an acute event.”

However, they point out that “our study population consisted of heart attack survivors and so the findings cannot be readily generalized to the entire population of heavy exercisers.”

On the other end of the spectrum, the journal also included research from Spain related to mortality in elite athletes. The investigation included over 42,000 top athletes, of which 707 were women, and examined the beneficial health effects of excessive exercise, particularly in decreasing cardiovascular disease and cancer risk. Senior investigator Alejandro Lucia, MD, PhD, said in the article, “What we found on the evidence available was that elite athletes (mostly men) live longer than the general population, which suggests that the beneficial health effects of exercise, particularly in decreasing cardiovascular disease and cancer risk, are not necessarily confined to moderate doses.”

With the majority of Americans still at risk for obesity, cardiovascular disease and diabetes, regular moderate exercise is still recommended by these researchers. As Hippocrates, the father of medicine, once said, “Everything in excess is opposed to nature.”

Previously: Study reveals initial findings on health of most extreme runners, The exercise pill: A better prescription than drugs for patients with heart problems?, Examining how prolonged high-intensity exercise affects heart health and Study reveals initial findings on health of most extreme runners
Photo by: Matthias Weinberger

Jen Baxter is a freelance writer and photographer. After spending eight years working for Kaiser Permanente Health plan she took a self-imposed sabbatical to travel around South East Asia and become a blogger. She enjoys writing about nutrition, meditation, and mental health, and finding personal stories that inspire people to take responsibility for their own well-being. Her website and blog can be found at www.jenbaxter.com.

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From August 11-25, Scope will be on a limited publishing schedule. During that time, you may also notice a delay in comment moderation. We’ll return to our regular schedule on August 25.

Cardiovascular Medicine, Research, Stanford News

Study highlights increased risk of death among patients with atrial fibrillation who take digoxin

Study highlights increased risk of death among patients with atrial fibrillation who take digoxin

After a decade of focusing on treatments for heart failure and heart attacks, it’s atrial fibrillation’s turn in the spotlight, said Mintu Turakhia, MD, MAS,  assistant professor of cardiology and director of cardiac electrophysiology for Palo Alto VA Health Care System.

“It’s a huge cost to society and one of the most common inpatient diagnoses,” Turakhia said.

Atrial fibrillation is an irregular and rapid heart rate — caused by spasms of the heart’s upper chambers — that afflicts more than 3 million Americans, increasing their risk of stroke and heart failure. Turakhia and his team planned to dig beneath the surface of atrial fibrillation using data from more than 122,000 patients with recent atrial fibrillation diagnoses in the U.S. Department of Veterans Affairs (VA) health-care system.

They started by examining the efficacy of digoxin, a generic drug derived from the plant foxglove. The results were striking: Patients who received digoxin were 3 percent more likely to die than similar patients.

“The take-home point is to question whether people should really be on this drug,” Turakhia said in a release. “These data challenge the current guidelines.”

Both doctors and patients assumed digoxin was safe because derivatives of foxglove had been used for centuries, not because it had been proven safe or effective, Turakhia said. He said there are many other preferable treatments for atrial fibrillation and he plans to work to standardize treatment for atrial fibrillation in coming years.

“Can we be smarter about how we deliver atrial fibrillation care so it’s delivered efficiently with less variation?” Turakhia asked.

The study will be published in the Aug. 19 issue of the Journal of the American College of Cardiology, which appears online today.

Becky Bach is a former park ranger who now spends her time writing, exploring, or practicing yoga. She’s currently a science writing intern in the medical school’s Office of Communication & Public Affairs.

Previously: Hybrid procedure helps treat difficult cases of atrial fibrillation and Newly approved drug appears to provide more cost-effective stroke prevention than warfarin

From August 11-25, Scope will be on a limited publishing schedule. During that time, you may also notice a delay in comment moderation. We’ll return to our regular schedule on August 25.

Cardiovascular Medicine, Patient Care, Stanford News, Technology, Videos

“Liberated from LVAD support”: One patient’s story

“Liberated from LVAD support”: One patient’s story

One of the first things I noticed about Donna Jackson — 68 years old when I met her in 2011 — was her decisive nature. She had a schedule filled with activity, and regardless of how many people (many of her children, grandchildren, great-grandchildren, in-laws and friends live very near at hand) came to visit in her modest home in Central California, she was a certain force of calm. She was also someone who did not like restrictions on what she could do.

Back then, she was just a few months out from surgery at Stanford Hospital to implant a mechanical pump, a left ventricular assist device or LVAD, on her heart. She knew it had saved her life, but she chafed at the battery, back-up battery and controller she had to wear at all times. Before the surgery, she had been a regular at a water aerobics class, and she loved to swim with her grandchildren. Even in those early months, Jackson was leaning on her Stanford doctors to find a way to get her back in the water. She asked her cardiologist, Dipanjan Banerjee, MD, to consider allowing her to swim in a wetsuit.

Banerjee did her one better. It had become apparent to him that she could be one of that small percentage of LVAD recipients whose heart recovers after the rest that the LVAD gives it and who no longer need the device. (He had been waiting, he said, to find a patient “who can be liberated from LVAD support.”) By Spring 2013, a little less than three years after her LVAD implantation, Banerjee and Jackson’s surgeon, Richard Ha, MD, put Jackson in an even smaller percentage. She became the first person to have her LVAD deactivated by catheter in the most minimally invasive approach yet.

The challenge set by Jackson for her Stanford team — and its groundbreaking procedural response — appears today in the August issue of the Annals of Thoracic Surgery. The lead author of the paper is Sanford Zeigler, MD, a cardiothoracic surgery resident.  Ha, surgical director of the hospital’s Mechanical Circulatory Support Program is the paper’s senior author, and Banerjee, medical director of Mechanical Circulatory Support Program, is a co-author. As they explain in the paper, Jackson, nearing 71,  was a high surgical risk for complete removal of the implant — that would have required them to crack open her ribs again — a procedure that’s followed typically by a long and sometimes painful recovery.  So, her doctors instead threaded a slim plastic tube through a small incision to her femoral artery in the groin and up to her aorta, allowed them to plug the flow of blood to the LVAD. Then, they cut, cleaned and capped the wiring powering the LVAD so it no longer emerged from an opening in her abdomen. (The LVAD remains inside Jackson’s chest.)

The new catheter-based deactivation of the LVAD has value beyond Jackson’s way of life, as the paper explains. She inspired the team to begin research on how to predict which LVAD patients might be like her and reach a point where they no longer need the LVAD. “If we can find out which patients are going to recover sooner, we can be more aggressive with them so they can be liberated from the LVAD,” said Banerjee, “and many of these patients will not want or be able to tolerate a complete removal of the LVAD.”

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