Beneficial cardiovascular effects of bariatric surgical and dietary weight loss in obesity

Multimodal cardiovascular magnetic resonance quantifies regional variation in vascular structure and function in patients with coronary artery disease: relationships with coronary disease severity

BACKGROUND

Cardiovascular magnetic resonance (CMR) of the vessel wall is highly reproducible and can evaluate both changes in plaque burden and composition. It can also measure aortic compliance and endothelial function in a single integrated examination. Previous studies have focused on patients with pre-identified carotid atheroma. We define these vascular parameters in patients presenting with coronary artery disease and test their relations to its extent and severity.

METHODS AND RESULTS

100 patients with CAD [single-vessel (16%); two-vessel (39%); and three-vessel (42%) non-obstructed coronary arteries (3%)] were studied. CAD severity and extent was expressed as modified Gensini score (mean modified score 12.38 ± 5.3). A majority of carotid plaque was located in the carotid bulb (CB). Atherosclerosis in this most diseased segment correlated modestly with the severity and extent of CAD, as expressed by the modified Gensini score (R = 0.251, P < 0.05). Using the AHA plaque classification, atheroma class also associated with CAD severity (rho = 0.26, P < 0.05). The distal descending aorta contained the greatest plaque, which correlated with the degree of CAD (R = 0.222; P < 0.05), but with no correlation with the proximal descending aorta, which was relatively spared (R = 0.106; P = n. s.). Aortic distensibility varied along its length with the ascending aorta the least distensible segment. Brachial artery FMD was inversely correlated with modified Gensini score (R = -0.278; P < 0.05). In multivariate analysis, distal descending aorta atheroma burden, distensibility of the ascending aorta, carotid atheroma class and FMD were independent predictors of modified Gensini score.

CONCLUSIONS

Multimodal vascular CMR shows regional abnormalities of vascular structure and function that correlate modestly with the degree and extent of CAD.

Value of weight reduction in patients with cardiovascular disease

OPINION STATEMENT

Obesity is an independent risk factor for cardiovascular (CV) disease and contributes markedly to individual CV risk factors, including hypertension, diabetes mellitus, dyslipidemia, and other chronic conditions, such as osteoarthritis, obstructive sleep apnea, and physical deconditioning. Obesity, defined as a body mass index ≥30 kg/m(2), is associated with increased morbidity and mortality, particularly in severely obese patients with a body mass index ≥35 kg/m(2). Physical activity, healthy eating and behavioral modification are three pivotal approaches to treating obesity. Some individuals may benefit from pharmacologic agents to achieve meaningful weight loss. Unfortunately, there are few such agents at present with proven efficacy and safety profiles. In this review, we discuss the obesity epidemic and its detrimental effects on the CV system, and focus on exercise training and on established pharmacologic agents as well as those on the horizon. We conclude by summarizing the surgical therapeutic options available to treat obesity and the evidence supporting the CV benefits of surgery, and discuss the potential adverse effects of both pharmacologic and surgical options.

Obesity and left ventricular dilatation in young adulthood: the Bogalusa Heart Study

BACKGROUND

Cardiac enlargement is an important predictor of adverse cardiovascular (CV) events. Left ventricular (LV) dilatation is a precursor both of LV dysfunction and clinical heart failure. The present study examines risk factors for LV dilatation among 832 young adults (341 male, 491 female) who participated in the Bogalusa Heart Study.

HYPOTHESIS

A unique set of risk factors predicts LV dilatation among young adults.

METHODS

Standard ventricular dimensions were determined by M-mode echocardiography and indexed to height using a standard method. LV dilatation was considered as the top 20th percentile of LV end-diastolic dimension indexed to height. Logistic regression models were used, stratified by race and sex, to assess the relationship of CV risk factors with quintile of LV end-diastolic dimension indexed to height.

RESULTS

The mean age (standard deviation) of men and women in the population was 36.4 years (3.9 years) and 35.9 years (4.6 years), respectively. In sex-specific models adjusted for age, race, systolic and diastolic blood pressure, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, and glycosylated hemoglobin, body mass index (BMI) was a significant predictor of LV dilatation in both men and women. The odds ratio (95% confidence interval) for a 1-unit change in BMI was 1.12 (1.02-1.19) in men and 1.09 (1.05-1.13) in women. Among men, triglyceride level was also significantly associated with LV dilatation (P=0.03), whereas among women there was no such association.

CONCLUSIONS

Our findings indicate that obesity is the most consistent predictor of LV dilatation in both men and women, whereas triglyceride level was a significant predictor among men only.

Impact of orlistat-induced weight loss on diastolic function and heart rate variability in severely obese subjects with diabetes

Objective. Determine the impact of Orlistat-induced weight loss on metabolic profile and cardiovascular function in severely obese patients with type 2 diabetes. Methods. Twenty-nine patients were randomized either to a nonplacebo control group or to a treatment group with Orlistat thrice a day. Metabolic profile, anthropometric parameters, heart rate variability indices, and echocardiographic variables were measured before and after a 12-week treatment period. Results. Treatment with Orlistat induced a modest but significant weight loss compared to controls (3.7 ± 3.0 versus 0.5 ± 2.2 kg, resp.; P = .003). There was significant decrease in fasting glycemia (7.9 ± 3.0 versus 6.7 ± 2.2 mmol/L; P = .03) and significant improvements in left ventricular diastolic function (P = .03) and in the sympathovagal balance (LF/HF ratio) (P = .04) in the Orlistat group. Conclusion. These results suggest that a modest weight loss improves fasting glycemia, left ventricular diastolic function, and sympathovagal balance in severely obese patients with type 2 diabetes.

Effect of weight loss after weight loss surgery on plasma N-terminal pro-B-type natriuretic peptide levels

Natriuretic peptides have multiple beneficial cardiovascular effects. Previous cross-sectional studies have indicated that obese subjects have lower natriuretic peptide concentrations than those of normal weight. It is not known whether this relative natriuretic peptide deficiency is reversible with weight loss. We studied 132 obese subjects undergoing weight loss surgery with serial measurement of plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations at preoperative, early (1 to 2 months), and late postoperative (6 months) points. In addition, 20 subjects also underwent echocardiography at baseline and 6 months after surgery. Significant weight loss was observed after surgery (median body mass index 45.1, 41.0, and 32.9 kg/m(2) for the 3 corresponding points, analysis of variance p <0.001). The median NT-proBNP levels increased substantially (31.6, 66.9, and 84.9 pg/ml; p <0.001). The average intrasubject increase in NT-proBNP at the 2 postoperative points was 3.4 and 5.0 times the preoperative level (p <0.001 for both points vs preoperatively). In the multivariate regression models adjusted for clinical characteristics and insulin resistance, the strongest predictor of the change in NT-proBNP level 6 months after weight loss surgery was the change in weight (p = 0.03). Echocardiography showed a mean intrasubject reduction in left ventricular mass index of 18% (p <0.001) and mild improvements in diastolic function, with no change in ejection fraction. In conclusion, we have demonstrated that weight loss is associated with early and sustained increases in NT-proBNP concentrations, despite evidence of preserved systolic and improved diastolic function. These findings suggest a direct, reversible relation between obesity and reduced natriuretic peptide levels.