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American College of Cardiology's 64th Annual Scientific Session PM tip sheet for March 15, 2015

American College of Cardiology

The studies below will be presented at the American College of Cardiology's 64th Annual Scientific Session on Sunday, March 15.

1. Survey Suggests Cardiologists May Not Be Prepared to Counsel Patients on Heart Healthy Diets

Even though most doctors believe diet is important in preventing and managing cardiovascular disease, there are major gaps in their knowledge and, in turn, efforts to educate patients about heart healthy diets may be falling short, according to a recent survey of 236 cardiologists and internal medicine physicians and trainees at a large tertiary academic medical center.

The study found that although physicians rate nutrition to be as important as statins in terms of reducing the risk of cardiovascular disease, only 13.5 percent agreed or strongly agreed that they were adequately trained to discuss nutrition with patients. The 28-question online survey was administered to identify gaps in nutritional knowledge and assess physician attitudes and practices related to nutrition for cardiovascular disease prevention. Two out of three fact-based questions were answered correctly. Cardiologists and internal medicine physicians scored about the same. Nearly all (89.7 percent) knew the Mediterranean diet was shown to reduce cardiovascular disease in randomized controlled trials, but less than half (45.5 percent) knew that low-fat diets had never been shown to do so.

What was surprising to researchers was how many physicians surveyed were not equipped to give practical recommendations for choosing heart healthy foods. For example, while the physicians knew about the blood pressure lowering effects of fruits and vegetables and LDL-cholesterol lowering effects of soluble fiber (81.7 and 87.6 percent, respectively), a much smaller percentage of respondents were able to correctly identify foods high in soluble fiber or an oily fish (69.5 and 30.8 percent, respectively).

"It's one thing to know an oily fish is a good thing, but being able to advise patients on which types of fish are high in omega-3 fatty acid is another," said Eugenia Gianos, M.D., assistant professor of medicine in the Leon H. Charney Division of Cardiology at NYU Langone Medical Center and a study investigator.

The authors said the study underscores the need for additional training in nutrition for cardiologists and other physicians, as well as more opportunities to educate patients. Nearly two out of three doctors spent less than three minutes counseling patients about diet and lifestyle modifications.

"In some ways we were pleased to see that most doctors were spending any time discussing diet and exercise given how short medical appointments are these days, but we would have liked to see more referrals to dieticians," Gianos said.

The data are limited due to the low response rate (26.7 percent) and the fact that it was limited to a single center. Still, Gianos said she believes there is great potential to improve patient care through physician education with more extensive emphasis on diet in their core curriculum, self-learning opportunities and collaboration with dietitians or other health care professionals. She said this type of survey should be fielded at other medical centers.

The American College of Cardiology has identified heart healthy diets as critical for cardiovascular disease risk reduction and recommends physicians provide dietary guidance to those at risk for or with established cardiovascular disease.

Gianos will present the poster, "Diet and the Prevention of Cardiovascular Disease: Physicians' Knowledge, Attitudes, and Practices" on Sunday, March 15 at 9:30 a.m. PT/12:30 p.m. ET/4:30 p.m. UTC in Poster Hall B1.

2. Dark Chocolate Shows Health Benefits in Sedentary Older Adults

A new study suggests eating dark chocolate could help improve energy levels, raise exercise stamina and improve other measures of heart health in sedentary older adults.

The researchers analyzed blood samples, exercise endurance tests and skeletal muscle biopsies of 17 volunteers before and after a three-month period in which participants were randomly assigned to eat either a small amount of dark chocolate or a placebo daily. Neither the researchers nor the participants knew which participants received the placebo until after the study. Subjects given dark chocolate showed improvements in high-density lipoprotein (HDL, or "good" cholesterol) and increased proteins associated with metabolism and energy production. Exercise testing indicated these volunteers also had a higher capacity for exercise and more efficient energy production in their muscle cells.

The study is the first to evaluate the effects of dark chocolate at a biochemical and mechanistic level in sedentary older adults, said lead study author Pam Taub, M.D., assistant professor of medicine at the University of California, San Diego Health System and the study's lead author. She said the results suggest dark chocolate could be an inexpensive and beneficial treatment for older people who are unable to exercise due to disabilities or mobility limitations. Future research could help elucidate other physiological effects of dark chocolate and epicatechin, the component thought to be responsible for its health effects. The study was conducted with funding from the Hershey Company.

Taub will present the study, "Effects of Dark Chocolate (DC) on Exercise Capacity in Sedentary Older Adults (A Double Blind Placebo Controlled Trial)," on Sunday, March 15 at 9:30 a.m. PT/12:30 p.m. ET/4:30 p.m. UTC in Poster Hall B1.

3. Sleep Experiment Looks at Effects of Imposed Sleep Loss on Ambulatory Blood Pressure

There is growing evidence that sleep loss is associated with a higher likelihood of high blood pressure and other key cardiovascular and metabolic risk factors.

In the first interventional trial to examine whether, and the mechanisms by which, sleep deprivation might cause spikes in 24-hour blood pressure, people exposed to prolonged periods of sleep restriction versus normal sleep had significant increases in blood pressure during nighttime and sleep periods but not during the day. Researchers also reported a parallel increase in heart rate, suggesting that an impaired baroreflex--a physiological reflex that controls blood pressure levels by compensatory changes in heart rate and/or activation of the body's sympathetic fight or flight response may be mediating negative effects of sleep loss on blood pressure.

To date, only eight healthy, young, normal weight subjects have completed this intensive 16-day inpatient protocol, but researchers plan to enroll 30 or more subjects over the next two years. Participants in this randomized, cross-over trial will complete both the sleep restriction and normal sleep/control phase; getting four or nine hours of sleep, respectively. Ambulatory blood pressure measures are taken repeatedly during the inpatient protocol. Blood pressure and heart rate levels are then calculated for the entire 24-hour period, during the day, at night and during sleep to evaluate changes.

"This is exciting because it is the first study to try to establish causality by applying a rigorous, controlled study design that simulates the chronic sleep loss normally experienced by millions of adults," Naima Covassin, M.D., Ph.D., Mayo Clinic, Rochester, Minnesota, and the study's lead author said. "We know from previous studies that the risk of high blood pressure is 19-49 percent higher in people who sleep six hours or less a night compared to those who sleep for seven or eight hours, and Americans generally don't get enough sleep."

Covassin will present the study, "Experimental Sleep Restriction Increases Nocturnal Blood Pressure and Attenuates Blood Pressure Dipping in Healthy Individuals" on Sunday, March 15 at 9:45 a.m. PT/12:45 p.m. ET/4:45 p.m. UTC in Poster Hall B1.

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