Обзор американских кардиологических журналов за неделю (ссылки)

[Chevychelov]

One-year lifestyle intervention beneficial for severely obese adults
Goodpaster BH. JAMA. 2010;doi:10.1001/jama.2010.1505.
Ryan DH. JAMA. 2010;doi:10.1001/jama.2010.1531.

Severely obese adults who adhered to an intensive lifestyle intervention using behavior-based diet and physical activity for 1 year experienced significant improvements in weight loss and cardiometabolic risk factors, according to researchers at the University of Pittsburgh School of Medicine.

Bret H. Goodpaster, PhD, and colleagues presented 1-year data on the effects of intensive lifestyle intervention in severely obese adults at the 28th Annual Scientific Meeting of the Obesity Society. The results were simultaneously published in the Journal of the American Medical Association.

The study included 130 adults aged 30 to 55 years with severe obesity who were recruited by local advertisements and mass mailings. The participants were randomly assigned to two groups for a 1-year: diet and physical activity regimen for 1 whole year or diet with a physical activity regimen that began after 6 months. All participants attended group sessions and received individual and telephone contacts.

Both groups lost a significant amount of weight in the first 6 months, but the initial physical activity group lost significantly more weight than the delayed activity group: 10.9 kg vs. 8.2 kg. At 12 months, however, there was no significant difference in the weight loss between the groups: 12.1 kg in the initial physical activity group and 9.9 kg in the delayed activity group.

At 6 months, the initial physical activity group had significantly greater reductions in body fat and waist circumference compared to the delayed activity group, but at 12 months, there was no significant difference in loss between the groups. The initial activity group lost significantly more hepatic fat content. The researchers also noted improvements in blood pressure, serum liver enzyme levels, fasting insulin and insulin resistance in both groups.

“Our data make a strong case that serious consideration should be given by health care systems to incorporating more intensive lifestyle interventions similar to those used in our study,” the researchers concluded. “Additional studies are clearly needed to determine long-term efficacy and cost-effectiveness of such approaches.”

In an accompanying editorial, Donna H. Ryan, MD, of Pennington Biomedical Research Center, Louisiana State University System, and Robert Kushner, MD, MS, of Northwestern University Feinberg School of Medicine, said studies such as this one “are needed to unravel the causes, identify prevention strategies and develop the best treatments for obesity.

“Optimal treatment approaches for class 2 and class 3 obesity are underexplored, while payment approaches for interventions known to work have yet to be adopted,” the editorialists wrote.
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Dyssynchrony indices not predictive of response to CRT
Miyazaki C. Circ Heart Fail. 2010;3:565-573.

New data from Circulation: Heart Failure suggest that dyssynchrony indices should not be used to guide use of cardiac resynchronization therapy in patients with HF.

“Multiple small retrospective studies suggested that various echocardiographic dyssynchrony indices have high sensitivity and specificity for identifying patients with a favorable response to cardiac resynchronization therapy (CRT),” the researchers commented in their study. “However, the multicenter prospective Predictors of Response to CRT (PROSPECT) trial was not able to identify any echocardiographic dyssynchrony parameter that added significant incremental value to the current simple QRS duration and clinical selection criteria for CRT.”

To help further clarify the role of dyssynchrony indices in CRT, the researchers performed a comprehensive, prospective, single-center trial enrolling 184 patients with HF with anticipated CRT from September 2005 to September 2007.

The final study population (n=131) had wide QRS and left ventricular ejection fraction <35%. All patients underwent clinical evaluation, echocardiography, Minnesota Living with Heart Failure Questionnaire, 6-minute walk distance and cardiopulmonary exercise testing for measurement of peak oxygen consumption before implantation and 6 months after implantation. Researchers analyzed 14 dyssynchrony indices by timing intervals (98%), tissue velocity (96%), M-mode (94%), tissue Doppler strain (92%), 2-D speckle strain (65%-86%) and 3-D echocardiography (79%).

At the 6-month follow-up, researchers reported reverse remodeling (end-systolic volume reduction >15%) in 55% of patients and more frequently in those without vs. with ischemic cardiomyopathy (71% vs. 42%; P=.002). Dyssynchrony index did not predict reverse remodeling in nonischemic cardiomyopathy, whereas indices derived using ischemic cardiomyopathy M-mode (area under curve [AUC], 0.67), tissue Doppler strain (AUC, 0.79), and isovolumic time (AUC, 0.76) were predictive of reverse remodeling (P<.05 for all).

Additionally, no indices assessed by Minnesota Living with Heart Failure Questionnaire, 6-minute walk distance or peak oxygen consumption were predictive of clinical response.

Limitations of note included lack of paired data for clinical response variables in some patients, the possibility of differences in data analysis between this and other studies, as well as the possibility that adjustment for LV lead position relative to dyssynchrony and scar may have improved the predictive value of mechanical dyssynchrony for reverse remodeling.

“The current findings, in concert with those of the PROSPECT and Cardiac Resynchronization in Heart Failure studies, indicate that the decision to use CRT should be based on standard guidelines and do not support a routine clinical use of any echocardiographic dyssynchrony indices to select patients for CRT,” the researchers wrote. “Although superior measures of mechanical dyssynchrony may be developed, the consistent findings observed with the large number of parameters assessed in this study do not engender optimism that use of CRT can be further refined by measurement of mechanical dyssynchrony in patients with advanced symptoms, low ejection fraction and conduction delay.”