Smokers' arteries stiffen twice as fast as those of nonsmokers, possibly increasing their risk for myocardial infarction, stroke and other problems, according to a study published in the Journal of the American College of Cardiology (JACC).
For the study, researchers at Tokyo Medical University evaluated the brachial-ankle pulse wave velocity--the speed at which blood travels from the heart to the brachial artery, the main blood vessel of the upper arm and the faraway ankle--of 2,054 Japanese adults across five to six years. They found that the annual change in velocity was higher in smokers than nonsmokers, signaling that smokers had stiffer arteries. In addition, the study determined that smokers' medium- and large-sized arteries stiffened at double the rate as those of nonsmokers. The researchers also identified a dose-response relationship between cigarette consumption and accelerated arterial stiffening.
Commenting on the findings, an associate professor of medicine and cardiology at New York City-based Mount Sinai Medical Center notes that the results emphasize the cumulative nature of smoking-induced damage and suggests that physicians use the findings when urging patients to quit smoking (Tomiyama et al., JACC, May 2010 [subscription required]; Edelson, HealthDay, 4/26).
As reported in today's Daily Briefing, gene-expression profiling may be a safer and more effective method to test for heart transplant rejection than the traditional biopsy technique, a study in NEJM finds.
Currently, endomyocardial biopsies--in which providers insert a catheter through a neck vein to snip a small piece of heart tissue--is the standard method of monitoring organ rejection in cardiac transplant recipients. However, biopsies may be uncomfortable for patients and are associated with rare but potentially serious complications, according to the study.
Noting these drawbacks, researchers from Stanford University Medical Center conducted a study to test the effectiveness of a new, noninvasive technique known as AlloMap, which examines 11 genes to determine the likelihood of a rejection episode. For the study, the researchers assigned 602 patients who had a heart transplant six months to five years earlier to undergo either routine biopsies or gene testing.
After an average 19-month follow-up that assessed patients for rejection, graft dysfunction, death or a new transplant, the researchers found that 14.5% of patients who received genetic testing had experienced at least one of those events, compared with 15.3% of individuals who underwent biopsies. The groups' two-year mortality rates were also similar, at 6.3% among those who had genetic testing and 5.5% among those who had biopsies.
However, the genetic testing group had fewer rejection episodes--34 compared with 47 in the biopsy group. Additionally, the genetic testing group's satisfaction scores increased across the study, while scores in the biopsy group remained stagnant. The researchers note that their study was limited because it did not include patients who had recently undergone transplant surgery; therefore, the patients were at a lower risk of rejection.
The findings call into question the frequency of testing for rejection episodes, writes a deputy editor at NEJM in an accompanying editorial. He notes that among the genetic testing group, only six of the 34 rejection episodes were found through test results, while the rest were identified through symptoms or an echocardiogram, the Los Angeles Times reports (Pham et al., NEJM, 4/22; Jarcho, NEJM, 4/22; Pollack, Times, 4/22 [registration required]; Maugh, Los Angeles Times "Booster Shots," 4/22 [registration required]).
Eating large amounts of sugar may hurt cardiac health, according to research published in JAMA.
For the study, researchers from the Emory University School of Medicine in Atlanta analyzed the dietary habits of 6,113 adults between 1999 and 2006 and grouped them based on their sugar intake and cholesterol levels; the highest sugar-intake group consumed 46 teaspoons per day, compared with three teaspoons daily among the lowest sugar-intake group. On average, nearly 16% of individuals' daily caloric intake came from sugar, compared with about 11% in the late 1970s.
The highest sugar consumers--those who got 25% or more of their daily calories from sugar--were more likely to have higher risk factors for heart disease, such as lower levels of good cholesterol and higher levels of triglycerides, compared with individuals whose sugar intake accounted for 5% of their daily caloric intake.
Although efforts to promote cardiovascular health have focused on low-fat and low-cholesterol diets, the researchers say their findings demonstrate a need to reassess dietary recommendations and further investigate how carbohydrates and sugars influence heart health (Welsh et al., JAMA, 4/21 [subscription required]; Smith, MedPage Today, 4/20; Steenhuysen, Reuters, 4/20; Edelson, HealthDay, 4/20).