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Cardiovascular Medicine

Cardiovascular Medicine, Patient Care

One person’s normal = another person’s heart attack?

One person's normal = another person's heart attack?

Much has been written about calculating your BMI (or body mass index, the relationship between your height to your weight) and what it might indicate about your health.

Similarly, the glucose level in your bloodstream and what it says about your risk of diabetes.

What you don’t hear much about, and what I learned yesterday, is how much the meaning of those numbers can vary between people. A healthy BMI for one person might put another person at risk for heart disease.

I was visiting the Stanford South Asian Translational Heart Initiative run by Rajesh Dash, MD, PhD, along with some Biodesign fellows I’ve been following (more about that in a later post). By way of background on the clinic, Dash explained the high risk of heart disease in the South Asian population. (My colleague Becky Bach blogged about that risk last year.)

Dash said one challenge in helping South Asians avoid heart disease comes from the definitions of “overwieight” and “diabetic”. Dash said that South Asians tend to have more fat per body weight, and so might have an acceptable BMI but still have an amount of fat that puts them at risk for heart disease. Similarly, a South Asian person who is pre-diabetic might benefit from diabetes medication.

“We see a lot of glucose levels that are technically normal but still troubling,” he told me. “Their risk of a cardiovascular event is almost as high as for someone who has diabetes.”

For a population that has four times more heart attacks in California than other ethnic groups, it seemed especially troubling that a mere definition might be preventing them from getting appropriate care.

That got me wondering how those numbers apply to other populations. Or to me.

I had my yearly blood work done recently and was pleased to see that everything was “normal”. I’m curious if in a decade people like Dash and others might have collected enough data to sway the way our values get reported. A set of numbers that is normal for my gender and ethnicity might trigger additional screening in another person, or be considered better than normal for someone else.

Previously: A ssathi (partner) to thwart heart disease in South Asians and Biodesign program welcomes last class from India

Cardiovascular Medicine, Pediatrics, Pregnancy, Surgery

Baby with rare heart defect saved by innovative surgery

Baby with rare heart defect saved by innovative surgery

jackson-lane-stanford-childrens560

Elyse Lane was 20-weeks pregnant when she learned that her unborn son had a rare and severe heart defect. Her baby was missing his pulmonary valve and his pulmonary artery was 10 times the normal size.

The outlook was bleak. The baby’s enlarged artery hampered his blood and oxygen flow, a condition called tetralogy of Fallot, and his missing pulmonary valve made the defect worse.

Fortunately, Lane and her husband, Andy Lane, a former Major League Baseball coach with the Chicago Cubs, were referred to Frank Hanley, MD, a cardiothoracic surgeon at Stanford Children’s Health. Hanley had experience with this kind of heart defect and knew how to perform the delicate surgery needed to repair their baby’s heart.

The Lanes recount the story of their son’s lifesaving surgery on the Lucile Packard Children’s Hospital blog:

When he was just five days old, Jackson underwent a 13-hour operation that would save his life. Hanley and his team did a complex overhaul of Jackson’s heart: they inserted a pulmonary valve, reduced the size of Jackson’s right pulmonary artery, and enlarged his small, disconnected, left pulmonary artery. Hanley also used an innovative and intricate procedure known as the LeCompte maneuver, which altered the pathway of Jackson’s right and left pulmonary arteries from the back of the heart and aorta to the front. This gave his severely compromised bronchial tubes room to grow and remodel after surgery was over.

As the story explains, Jackson’s heart will need some maintenance in the future, but he should live a normal and long life.

“He can now do anything he wants in life,” said Elyse Lane in in the blog piece. “He’s already made it through the biggest challenge.”

Previously: Patient is “living to live instead of living to survive,” thanks to heart repair surgery, A very special small package: Three-pound baby receives pacemaker, Advancing heart surgery for the most fragile babies, and Little hearts, big tools
Photo courtesy of Lucile Packard Children’s Hospital

Cardiovascular Medicine, In the News, Public Health, Research, Women's Health

A look at why young women who have heart attacks delay seeking care

A look at why young women who have heart attacks delay seeking care

317916781_c8bb9b352e_zHeart attacks kill more than 15,000 women in the U.S. each year and are disproportionately deadly for females under the age of 55. Although several studies, including those by Stanford cardiologist Jennifer Tremmel, MD, have investigated the signs and consequences of heart attacks in men and women, relatively little is known about heart disease in women or why it’s so lethal for young females. And according to new research, misconceptions about the risk factors and signs of coronary heart disease may be why young females are less likely to recognize and seek emergency care for a heart attack.

In the study, published yesterday in Circulation: Cardiovascular Quality and Outcomes, a research team led by Judith Lichtman, PhD, MPH, of the Yale School of Public Health, interviewed 30 women between the ages of 30 to 55  who had been hospitalized for a heart attack. The researchers identified five common themes among the symptoms and treatments of the women they interviewed, and one potentially important finding was that women were unsure they’d had a heart attack so they were hesitant to seek medical treatment.

From an NPR story:

A heart attack doesn’t necessarily feel like a sudden painful episode that ends in collapse, [Lichtman] notes. And women are more likely than men to experience vague symptoms like nausea or pain down their arms.

“Women may experience a combination of things they don’t always associate with a heart attack,” Lichtman says. “Maybe we need to do a better job of explaining and describing to the public what a heart attack looks and feels like.”

Tremmel also provided comment on the study, saying it indicates a need to encourage women to seek help for medical concerns. “This is an ongoing issue in the medical field,” she said. “…We all have to empower women patients, so they know that they need to not be so worried about going to the hospital if they’re afraid there’s something wrong.”

Previously: New test could lead to increase of women diagnosed with heart attack, Heart attacks and chest pain: Understanding the signs in young womenAsk Stanford Med: Cardiologist Jennifer Tremmel responds to questions on women’s heart healthPaper highlights major differences in disease between men and women and Gap exists in women’s knowledge of heart disease
Photo by Simon Mason

Ask Stanford Med, Cardiovascular Medicine, Events, Genetics

A conversation about using genetics to advance cardiovascular medicine

A conversation about using genetics to advance cardiovascular medicine

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In recognition of American Heart Month, Stanford Health Care is hosting a heart fair on Saturday. The free community event includes a number of talks ranging in topic from the latest developments in treating atrial fibrillation to specific issues related to women’s heart health.

During the session on heart-disease prevention, Joshua Knowles, MD, PhD, will deliver a talk titled “How We Can (and Will) Use Genetics to Improve Cardiac Health.” Knowles’ research focuses on familial hypercholesterolemia, a genetic disease that causes a deadly buildup of cholesterol in the arteries. He and colleagues recently launched a project that uses a big-data approach to search electronic medical records and identify patients who may have the potentially fatal heart condition.

To kick off the conversation about preventing heart disease, I contacted Knowles to learn more about how the genomics revolution is changing the cardiovascular medicine landscape and what you can do to determine if you have a genetic heart disorder. Below he explains why heart disease is a “complex interplay between genetics and environment” and what the future may hold with respect to personalized treatments and pharmacogenetics.

Let’s start by talking about your work on familial hypercholesterolemia (FH). How has the understanding of the genetic basis of FH evolved over the last few years, and what key questions remain unanswered?

For FH, there has been a revolution in our understanding. FH causes very elevated cholesterol levels and risk of early onset heart disease. We used to think that it affected 1 in 500 individuals, but recent studies have pointed out that this is probably an underestimate and it may affect as many as 1 in 200 people. This means that there may be as many as 1 million people in the United States who are affected. We have also identified new genes that cause FH, and the identification of some of these genes has directly translated into the development of a new class of drugs (so called PCSK9 inhibitors) to treat this condition.

What steps can patients take to determine if they are at risk of, or may have, a genetic cardiovascular disorder like FH?

The easiest way is to know about your family history of medical conditions- to know what illnesses affected parents, grandparents, uncles, aunts and other relatives. Of course, genes aren’t the only things that are passed in families. Good and bad habits, such as exercise patterns, smoking and diet, are also passed down through the generations. But a family history of heart disease or certain forms of cancer is certainly a risk factor.

Past research suggests that patients with a genetic predisposition to heart disease can significantly reduce their chances of having a heart attack or stroke by making changes to their lifestyle, such as eating a diet rich in fruits and vegetables. Can lifestyle changes overcome genetics?

Heart disease is a result of the complex interplay between genetics and environment – lifestyle, for instance. For some people with specific genetic conditions, such as familial hypercholesterolemia or hypertrophic cardiomyopathy, the effect of genetics tends to dominate the effect of environment because the genetic effect is so large.

For the vast majority of people without these “Mendelian” forms of heart disease, which follow the laws of inheritance were derived by nineteenth-century Austrian monk Gregor Mendel, it’s difficult to determine at an individual level how much of the risk is due to genes and how much is due to environment (this is for things like high blood pressure, high cholesterol, coronary disease). One clue is certainly family history. However, for most of these diseases the genes are not “deterministic” – that is, people are not destined to have these diseases. Some are more at risk than others, but there are certainly ways to mitigate genetic risk through lifestyle choices. Choosing not to smoke and exercising regularly are two examples of ways you can help to greatly minimize genetic risk.

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Cardiovascular Medicine, Health and Fitness, Public Health, Research, Women's Health

Even moderate exercise appears to provide heart-health benefits to middle-aged women

Even moderate exercise appears to provide heart-health benefits to middle-aged women

woman on bike

It’s no secret that exercise offers a plethora of health benefits; tons of research has established that. But I was still heartened to read about a new study showing that physically active middle-aged women had lower risks of heart disease, stroke and blood clots than did their inactive counterparts. (I read about the work on my phone as I walked home from a barre class last night, which made me feel especially happy about having had just worked out.)

Researchers from University of Oxford looked at data from 1.1 million women in the United Kingdom, who were followed for an average of nine years. From an American Heart Association release:

In the study:

  • Women who performed strenuous physical activity— enough to cause sweating or a faster heart beat — two to three times per week were about 20 percent less likely to develop heart disease, strokes or blood clots compared to participants who reported little or no activity.
  • Among active women, there was little evidence of further risk reductions with more frequent activity.

Physical activities associated with reduced risk included walking, gardening, and cycling.

Lead author Miranda Armstrong, MPhil, PhD, commented that “inactive middle-aged women should try to do some activity regularly,” but then noted that the results suggest that “to prevent heart disease, stroke and blood clots, our results suggest that women don’t need to do very frequent activity.” That’s good news, ladies!

The study appears in the journal Circulation.

Previously: Lack of exercise shown to have largest impact on heart disease risk for women over 30, Exercise is valuable in preventing sedentary death, Study shows regular physical activity, even modest amounts, can add years to your life, CDC report shows exercise becoming a popular prescription among doctors and Brisk walking reduces stroke risk among women
Image by Thomas Hawk

Cardiovascular Medicine, Chronic Disease, Research, Stanford News, Surgery, Transplants

Growing number of donor hearts rejected for transplantation, Stanford study finds

Growing number of donor hearts rejected for transplantation, Stanford study finds

KhushAs a health writer, I’ve interviewed and written about numerous heart patients whose lives were saved when someone else died and donated their hearts for transplantation.

Those patients expressed both the anguish of hoping and praying for a new heart — when that means someone else has to die — and the overwhelming gratefulness for those donor hearts that saved their lives.

So when I wrote a story about a new Stanford study that shows an increasing number of donor hearts being rejected for transplantation, it struck a chord.

The study, published today online in the American Journal of Transplantation, found that the number of hearts rejected for transplant by surgeons and transplant centers is on the rise despite the growing need for such organs. As cardiologist Kiran Khush, MD, the lead author of the study, said in my story on the work, “We’ve become more conservative over the past 15-20 years in terms of acceptance, which is particularly troubling because of the national shortage of donor hearts and the growing number of critically ill patients awaiting heart transplantation.”

Khush and her colleagues sought to study national trends in donor-heart use by examining data from the federal government’s Organ Procurement and Transplantation Network on all donated hearts from 1995-2010. Of 82,053 potential donor hearts, 34 percent were accepted and 48 percent were declined. The remainder were used for other purposes such as research.

The researchers found a significant decrease in donor heart acceptance, from 44 percent in 1995 to 29 percent in 2006, which rebounded slightly to 32 percent in 2010. They also found, as I wrote in the story:

Among a portion of donor hearts that are referred to as “marginal” — those with undesirable qualities, such as being small or coming from an older donor — their use in transplantation varied significantly across geographical regions depending on choices made by the surgeons and the transplant centers.

The study explored possible reasons for so few organs being accepted. Increasing scrutiny by regulatory agencies of the 140 or so transplant centers across the country may have had the unintended result of making surgeons and centers more risk averse and as a result reject more hearts. Also, an increasing us of mechanical circulatory support devices that help keep patients alive while waiting for donor hears, may cause surgeons to wait longer for “better hearts.”

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Cardiovascular Medicine, Stanford News, Videos

C’mon, be heart healthy

C'mon, be heart healthy

Is your heart healthy? Are you at risk for heart disease? In recognition of American Heart Month, Stanford Health Care has launched a campaign to help people find the answers to those questions. The interactive video above, and this Q&A on preventing heart disease, are good places to start.

Previously: Lack of exercise shown to have largest impact on heart disease risk for women over 30, Mysteries of the heart: Stanford Medicine magazine answers cardiovascular questions, Ask Stanford Med: Answers to your questions about heart health and cardiovascular research, Either you’re a woman or you know one: Help spread the message of women’s heart health and Why some healthy-looking young adults may still be at risk for heart disease

Cardiovascular Medicine, Emergency Medicine, In the News, Research, Women's Health

New test could lead to increase of women diagnosed with heart attack

New test could lead to increase of women diagnosed with heart attack

12192161504_34544b2f38_zSimilar numbers of men and women come to the emergency room complaining of chest pain, and similar numbers of men and women die from heart disease each year (in fact, slightly more than half are women), so why are only half as many women being diagnosed with heart attacks?

A study recently published in the BMJ and funded by the British Heart Foundation suggests that the reason for the difference lies in the diagnostic methods: blood tests. Researchers at the University of Edinburgh found that if blood tests are administered with different criteria for each gender, women’s heart attack diagnoses are much higher. Better tests could limit under-diagnosis and prevent women from dying or suffering from future heart attacks. (And women are more likely than men to die after suffering an attack; twice as likely in the few weeks afterward!)

Blood diagnostic tests measure the presence of troponin, a protein released by the heart during an attack. Previous research showed that men produce up to twice as much troponin as women, so Anoop Shah, MD, and fellow authors hypothesized that if different thresholds of troponin levels were used for men and women, it would correct the disparity.

The researchers administered two tests on patients complaining of chest pain, once using methods that are standard around the world, and then again using a highly sensitive troponin test and gender-specific thresholds. MNT reports:

When using the standard blood test with a single diagnostic threshold, heart attacks were diagnosed in 19% of men and 11% of women. However, while the high-sensitivity blood tests yielded a similar number of diagnoses in men (21%), the number of heart attack diagnoses in women doubled to 22%.

In addition, the researchers observed that participants whose heart attacks were only diagnosed by the high-sensitivity test with gender-specific diagnostic thresholds were also at a higher risk of dying or having another heart attack in the following 12 months.

This research included a little more than 1,000 subjects; the BHF is now funding a clinical trial on more than 26,000 patients to verify the results.

Photo by MattysFlicks

Big data, Cardiovascular Medicine, Chronic Disease, Research, Stanford News

Big data used to help identify patients at risk of deadly high-cholesterol disorder

Big data used to help identify patients at risk of deadly high-cholesterol disorder

Familial hypercholesterolemia is not exactly a catchy name. But Stanford cardiologist Josh Knowles, MD, is determined to make it easier to remember. This little known, high-cholesterol disease is a silent killer. If you don’t know you have it, it can strike suddenly – and years before most people ever start worrying about heart attacks.

Knowles and fellow researchers at Stanford have launched a new research project aimed at identifying people at-risk of having FH. Using “big data” research methods and software that “teaches” a computer how to recognize patterns, researchers plan to comb through electronic medical records at Stanford hospitals and, if successful, pinpoint those who might have the disease and not know it.

In a story I wrote on the new project, Knowles described how this innovative technology could potentially be used to transform health care:

Machine learning, in which computer algorithms learn to recognize patterns within data, is widely used by Internet businesses such as Amazon and Netflix to improve customer experience, get information about trends, identify likes and dislikes and target advertisements. These techniques have not been widely applied in medicine, but we believe that they offer the potential to transform health care, particularly with the increased reliance on electronic health records.

Using these methods to help identify patients with FH is a good place to start, Knowles said, since there are currently few systematic approaches to finding people with FH, and many doctors are unfamiliar with the disease. As he told me:

This disorder certainly leads to premature death in thousands of Americans each year … Less than 10 percent of cases are diagnosed, leaving an estimated 600,000 to 1 million people undiagnosed. If found early enough and treated aggressively with statin-based regimens, people can live longer, healthier lives.

The project is part of a larger initiative called FIND FH (Flag, Identify, Network, Deliver), a collaborative effort involving Stanford Medicine, Amgen Inc., and the nonprofit Familial Hypercholesterolemia Foundation to use innovative technologies to identify individuals with the disorder who are undiagnosed, untreated, or undertreated.

Previously: Registration for Big Data in Biomedicine conference now open, Hope for patients with familial hypercholesterolemia and Born with high cholesterol
Photo by Dwight Eschliman

Cardiovascular Medicine, Patient Care, Stanford News

“This reinforced why I went into nursing”: The story of two nurses who resuscitated plane passenger

"This reinforced why I went into nursing": The story of two nurses who resuscitated plane passenger

Woo and BinghamStanford Health Care cardiac nurse coordinators Angela Bingham, RN, MSN, CNL, and Sophia Loo, RN, MSHCA, have cared for hundreds of patients with serious heart disease. And they’ve had access to sophisticated technology and colleagues who are skilled at teamwork. Then came the one time that none of that was at hand – and a life was at stake.

Last December, Loo and Bingham had just boarded a plane back home to San Jose from a national health-care conference when they heard a call for help. Both rushed forward and found a male passenger in obvious cardiac distress. They recognized instantly that he was near death, and what followed was a classic case of making the best of what they had.

In a story in yesterday’s Inside Stanford Medicine, Bingham and Loo share their experience and how much it meant to be able to do something they knew made a difference. “This reinforced why I went into nursing,” Loo told me for the story. “I was so humbled and grateful that I could do something; that Angela and I knew what to do.”

Photo by Norbert von der Groeben

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