Gastric bypass surgery is followed by lowered blood pressure and increased diuresis - long term results from the Swedish Obese Subjects (SOS) study

Optimization of Vitamin D Status After Roux-en-Y Gastric Bypass Surgery in Obese Patients Living in Northern Climate

BACKGROUND

Patients who undergo bariatric surgery are at risk for micronutrient deficiencies. The aims of this study were to determine the prevalence and predictors of vitamin D deficiency in obese patients residing in the northern climate, and to evaluate the effectiveness of a daily maintenance dose of vitamin D 2000 IU in preventing hypovitaminosis D within 1 year after bariatric surgery.

METHODS

A cohort study involving adult patients undergoing RYGB was conducted. Longitudinal changes in serum vitamin D concentrations and clinical parameters were measured and collected.

RESULTS

Data from 134 recipients of RYGB were analyzed. Hypovitaminosis D was identified in 86 patients (64 %), and was significantly affected by seasonal change and the number of comorbidities. Follow-up data were available in 60 patients. Vitamin D sufficiency was achieved in 62.5 % of those patients with baseline vitamin D insufficiency. A dose-response relationship of vitamin D intake was observed, with the most significant increase in 25(OH)D associated with daily vitamin D intakes ≥ 2000 IU.

CONCLUSIONS

The prevalence of hypovitaminosis D before RYGB was comparable to patients living in the non-northern climate. Daily vitamin D intake meeting at least 2000 IU is associated with greater improvement in serum vitamin D concentration.

Roux-en-Y gastric bypass alleviates hypertension and is associated with an increase in mid-regional pro-atrial natriuretic peptide in morbid obese patients

OBJECTIVE

To examine 24-h blood pressure (24BP), systemic haemodynamics and the effect of sodium intake on 24BP in obese patients before and after gastric bypass surgery [laparoscopic Roux-en-Y gastric bypass (LRYGB)], and to determine whether weight loss from LRYGB might be related to an increase in plasma concentrations of atrial natriuretic peptide.

METHODS

Twelve hypertensive and 12 normotensive morbidly obese patients underwent LRYGB: 24BP, systemic haemodynamics and mid-regional pro-atrial natriuretic peptide (MRproANP) were assessed before, 6 weeks and 12 months after surgery. The effect of high versus low sodium intake on 24BP was evaluated before and 12 months after LRYGB.

RESULTS

Six weeks after LRYGB, the average weight loss was 20 kg, with a further 21 kg weight loss 1 year after surgery. In hypertensive patients, 24BP was significantly reduced at 6 weeks, but not 1 year after LRYGB. However, antihypertensive medications were successively reduced from baseline to 1 year after surgery. In normotensive patients, there was no change in 24BP 6 weeks after LRYGB, but a tendency towards a reduction 1 year after the operation. Plasma concentrations of MRproANP were subnormal prior to surgery in hypertensive patients and increased by 77% 1 year after the operation. In normotensive patients, preoperative concentrations were normal and increased only by 6%. High sodium intake induced plasma volume expansion, increased stroke volume and cardiac output, but no significant change in 24BP - neither before nor after LRYGB.

CONCLUSIONS

LRYGB resulted in a significant 24BP reduction and a substantial increase in MRproANP plasma concentrations in hypertensive, obese patients 6 weeks after surgery, suggesting a causal link between obesity-hypertension and altered release/degradation of cardiac natriuretic peptides.

Effect of a Modest Weight Loss in Normalizing Blood Pressure in Obese Subjects on Antihypertensive Drugs

OBJECTIVE

To assess the effect of a lifestyle intervention in lowering/normalizing blood pressure (BP) levels in hypertensive (controlled or not) obese patients.

METHODS

In this prospective observational study, 490 obese hypertensive patients, 389 controlled (BP < 140/90 mm Hg; CH) and 101 uncontrolled (BP ≥ 140/90 mm Hg; UH) attended a 3-month lifestyle intervention. Before and after the intervention we assessed weight, waist circumference, fat mass, BP, metabolic and renal variables, and physical activity. A multivariate regression model was used to determine the predictors of BP changes.

RESULTS

18.9% of CH and 20.0% of UH were on ≥ 3 antihypertensive drugs. Weight change (average -4.9 ± 2.7%) was independent of the antihypertensive drugs employed. Systolic BP (SBP) decreased by 23 mm Hg and diastolic BP (DBP) by 9 mm Hg, in patients with UH most of whom (89%) normalized BP levels (in 49% after a weight loss < 5%). Age, gender, whole and central obesity, concomitance of type 2 diabetes, chronic renal disease, physical activity intensification, and pharmacological therapy did not affect BP lowering. In the regression analysis with SBP change as dependent variable, weight reduction (β = 0.523, p = 0.005) and group (UH vs. CH, β = -19.40, p = 0.0005) remained associated with SBP reduction. When DBP change was entered as dependent variable, baseline uric acid remained associated with DBP reduction (β = 0.824, p < 0.05).

CONCLUSION

Lifestyle interventions are useful for all obese hypertensive patients in most of whom a modest weight loss is sufficient to normalize BP levels avoiding the aggressive use of multiple antihypertensive drugs.

The brain melanocortin system, sympathetic control, and obesity hypertension

Excess weight gain is the most significant, preventable cause of increased blood pressure (BP) in patients with primary (essential) hypertension and increases the risk for cardiovascular and renal diseases. In this review, we discuss the role of the brain melanocortin system in causing increased sympathetic activity in obesity and other forms of hypertension. In addition, we highlight potential mechanisms by which the brain melanocortin system modulates metabolic and cardiovascular functions.

Proximal Roux-en-Y gastric bypass alters drug absorption pattern but not systemic exposure of CYP3A4 and P-glycoprotein substrates

STUDY OBJECTIVES

To evaluate the effect of Roux-en-Y gastric bypass surgery (RYGB) on the pharmacokinetics of midazolam (a CYP3A4 substrate) and digoxin (a P-glycoprotein substrate).

DESIGN

Prospective, nonblinded, longitudinal, single-dose pharmacokinetic study in three phases: presurgery baseline and postoperative assessments at 3 and 12 months.

PATIENTS

Twelve obese patients meeting current standards for bariatric surgery.

MEASUREMENTS AND MAIN RESULTS

At each study visit, patients received a single dose of oral digoxin and midazolam at 8 a.m. Blood samples were collected at regular intervals for 24 hours after dosing. Continuous 12-lead electrocardiogram (EKG), heart rate, blood pressure, and respiratory rate were monitored, and pharmacokinetic parameters from the three visits were compared. The peak plasma concentration (Cmax ) of midazolam increased by 66% and 71% at 3- and 12-month post-RYGB (p=0.017 and p=0.001, respectively), whereas the median time to peak concentration (Tmax ) was reduced by 50%. The mean Cmax for 1'-hydroxymidazolam increased by 87% and 80% at 3 and 12 months (p=0.001 and p<0.001, respectively). However, neither the area under the concentration-time curve (AUC) for midazolam nor the metabolite-to-parent AUC ratio changed significantly over time. For digoxin, the median Tmax decreased from 40 minutes at baseline to 30 and 20 minutes at 3 and 12 months, respectively. The mean AUC for digoxin, heart rate, and EKG patterns were similar across the three study phases.

CONCLUSION

Contemporary proximal RYGB increases the rate of drug absorption without significantly changing the overall exposure to midazolam and digoxin. The Cmax of a CYP3A4 substrate with a high extraction ratio was substantially increased after RYGB.

How to choose and use bariatric surgery in 2015

Severe obesity is associated with increased morbidity and mortality and represents a major health care problem with increasing incidence worldwide. Bariatric surgery, through its efficacy and improved safety, is emerging as an important available treatment for patients with severe obesity. Classically, bariatric surgery has been described as either a restrictive or a hybrid surgery, which is a combination of restriction and malabsorption. For most severely obese patients, bariatric surgery results in the remission of major obesity-related comorbidities including type 2 diabetes mellitus, sleep apnea, hypertension, and dyslipidemia. Thus, bariatric surgery reduces cardiovascular risk burden, and overall mortality risk. Early complications (< 30 days) after bariatric surgery were reported to be < 10% and tend to be lower in restrictive surgeries compared with hybrid surgeries. Most common early complications reported are gastric and anastomosis leak (1.6%-5.1%), bleeding (0.5%-3.5%), and pulmonary embolism (0.2%-1%). Long-term complications (> 30 days) might differ depending on the type of bariatric surgery. According to the type of surgery and the type of study, the 30-day operative mortality rates differ from 0.1% to 1.2%. Studies on postoperative outcomes, investigations on weight loss physiology, and mechanism of action after bariatric surgery provide a better understanding of the bariatric surgery metabolic benefits. In this article, we present an overview of bariatric procedures with their effects, including risks and benefits, on the severely obese patients' health. It provides evidence to support surgical treatment of severe obesity to achieve cardiovascular disease risk reduction in severely obese patients.

Gastrointestinal intervention ameliorates high blood pressure through antagonizing overdrive of the sympathetic nerve in hypertensive patients and rats

Background

We investigated the hypothesis that the favorable effects of gastrointestinal (GI) intervention on hypertension (HTN) and cardiovascular (CV) disturbances are mediated by antagonizing overdrive of the sympathetic nervous system (SNS).

Methods and Results

Hypertensive patients with metabolic disturbances underwent laparoscopic Roux‐en‐Y gastric bypass surgery, and spontaneously hypertensive rats (SHRs) underwent RYGB or sham surgery. Blood pressure (BP), heart rate (HR), endothelium‐dependent flow‐mediated dilation, and anthropometric as well as laboratory parameters were measured at baseline and during follow‐up. Changes of BP and HR in response to cold stress, renal sympathetic nervous activity (RSNA), vasoconstriction induced by electrical field stimulation, microinjection of nucleus of the solitary tract (NTS), and CV function and structure were examined in SHRs with or without surgery. Compared with baseline, BP and HR were significantly reduced in both hypertensive patients with type 2 diabetes and rats. Impaired endothelial‐dependent vasodilatation and metabolic disturbances in hypertensive patients were also ameliorated after surgery. CV disturbances were reversed by surgery in SHRs. Under acute cold exposure, the variations in BP and HR were smaller in surgically treated SHRs, compared to sham SHRs. RSNA and vasoconstriction induced by perivascular nerve stimulation as well as NTS‐mediated changes of BP were decreased in surgically treated SHRs, compared to sham SHR. Weight loss did not affect BP and RSNA in sham SHRs.

Conclusions

GI intervention ameliorates HTN in both hypertensive patients and rats by inhibiting overdrive of the SNS. Therefore, targeting gastrointestine could be a novel strategy to treat HTN with metabolic disturbances.

Endogenous Glucagon-Like Peptide-1 as a Potential Mediator of the Resolution of Diabetic Kidney Disease following Roux en Y Gastric Bypass: Evidence and Perspectives

Diabetic kidney disease in patients with type 2 diabetes strongly correlates with the incidence of major cardiovascular events and all-cause mortality. Pharmacological and lifestyle based management focusing on glycaemic, lipid, and blood pressure control is the mainstay of treatment but efficacy remains limited. Roux en Y gastric bypass is an efficacious intervention in diabetes. Emerging evidence also supports a role for bypass as an intervention for early diabetic kidney disease. This paper firstly presents level 1 evidence of the effects of bypass on hyperglycaemia and hypertension and then summarises emerging data on its effects on diabetic kidney disease. Glucagon-like peptide-1 is implicated as a central mediator of diabetes resolution following bypass through the incretin effect. It has been ascribed vasodilatory, pronatriuretic, and antioxidant properties and its exogenous administration or optimisation of its endogenous levels via dipeptidyl peptidase IV inhibition results in antioxidant and antiproteinuric effects in preclinical models of DKD. Some evidence is emerging of translation of coherent effects in the clinical setting. These findings raise the question of whether pharmacotherapy targeted at optimising circulating hormone levels may be capable of recapitulating some of the effects of bypass surgery on renal injury.

Improvements in the metabolic milieu following Roux-en-Y gastric bypass and the arrest of diabetic kidney disease

Roux-en-Y gastric bypass (RYGB) is an efficacious intervention for morbid obesity and has a diabetes-remitting effect in patients with obesity and type 2 diabetes mellitus, which occurs prior to significant weight loss. Roux-en-Y gastric bypass is also associated with early and sustained reductions in the risk factor profile for the progression of diabetic complications. Attention is therefore now being placed on RYGB as a metabolic intervention with the capacity to yield therapeutic benefit in relation to the progression of diabetic complications, such as diabetic kidney disease. As alterations in gut anatomy following RYGB coincide with attendant shifts in downstream enteroendocrine signals with direct and indirect resolutionary effects on the kidney, the concept of an endocrine gut-kidney axis post-RYGB is growing. With the model of a gut-kidney axis in mind, this article summarizes emerging data on the effects of RYGB on risk factors for diabetic kidney disease (hyperglycaemia, dyslipidaemia and hypertension), highlighting a potential role for glucagon-like peptide 1 in risk factor reduction.

Carotid intima-media thickness is reduced 12 months after gastric bypass surgery in obese patients with type 2 diabetes or impaired glucose tolerance

AIM

To investigate whether Roux-en-Y gastric bypass surgery (RYGB) - an in vivo model for normalisation of hyperglycaemia - improves carotid intima-media thickness (IMT) in patients with type 2 diabetes (T2D)/impaired glucose tolerance (IGT) and normal glucose tolerance (NGT).

METHODS

Observational prospective study, 34 obese patients (T2D (n = 14)/IGT (n = 4), and NGT (n = 16)) were investigated before and six and 12months after RYGB.

RESULTS

Mean carotid IMT was significantly reduced 12months after RYGB in patients with T2D/IGT (-0.041 mm (95% CI -0.069; -0.012, p = 0.005)) but not in patients with NGT (-0.010 mm (-0.039; 0.020, p = 0.52)). The between-group difference was not significant (p=0.13). Twelve months after RYGB, patients with respectively T2D/IGT and NGT demonstrated changes in weight: -29.9 kg, p<0.001/-30.6 kg, p < 0.001, HbA1c: -0.7%, p < 0.001/-0.1%, p = 0.33, systolic blood pressure: -2 mmHg, p = 0.68/-10 mmHg, p = 0.01 and diastolic blood pressure: -8 mmHg, p = 0.003/-11 mmHg, p < 0.001. 80% of T2D patients terminated antihyperglycaemic medication.

CONCLUSION

Mean carotid IMT was significantly reduced 12months after RYGB in patients with T2D/IGT which provides evidence to support that the earliest atherosclerotic changes in the arterial wall are reversible. Although numerically different from the changes observed in patients with NGT, the between-group difference was not statistically significant.

The role of bariatric surgery in the treatment of diabetes

The obesity epidemic contributes to approximately 44% of the world's type 2 diabetes burden. Bariatric surgery is an effective treatment for type 2 diabetes mellitus in patients with morbid obesity as it improves glycaemia, blood pressure, lipids and inflammation. This review describes the evidence supporting the addition of bariatric surgery to the treatment algorithms used by diabetologists. We emphasize the need to view bariatric surgery as an adjuvant therapy which should not be used instead of but rather together with best medical therapy.

Patient expectations of bariatric surgery are gender specific--a prospective, multicenter cohort study

BACKGROUND

The effect of bariatric surgery on weight loss and improvement of co-morbidities is no longer doubted. However, little attention has been given to the treatment goals from the patient's point of view (patient expectations). The objective of this study was to examine patients' expectations of bariatric surgery and identify gender differences.

METHODS

Bariatric patients were asked to complete a questionnaire. Statistical analysis was performed using chi-square, Pearson correlation coefficient, and Wilcoxon rank sum test.

RESULTS

Overall, 248 patients participated in this study (69.4% females). The male patients (45.2 yr, SD±11.1) were significantly older than the female (41.8 yr, SD±12.0; P = .04) and suffered significantly more often from diabetes, hypertension, hypercholesterolemia, and sleep apnea. One hundred thirty patients (52.4%) expected to lose at least 45 kg and 39 patients (15.7%)>70 kg. The mean expected excess weight loss was 71.8%. Females expected significantly more often that surgery alone would induce weight loss (P = .03). "Improved co-morbidity" was by far the highest ranked parameter.

CONCLUSION

The male bariatric surgery patients were older and suffered from more co-morbidities. Most of the patients had unrealistic weight loss goals and overestimated the effect of the surgical intervention. However, for both female and male patients, "improved co-morbidity" was the most important issue.

Laparoscopy for primary and secondary bariatric procedures

Recently obesity has been defined as a disease and has turned bariatric surgery into a part of a chronic illness management. Obesity induces several comorbidities leading to cardiovascular disease and mortality. The effects of bariatric surgery on these comorbidities used to be classified as weight-loss induced. However bariatric surgery has recently been termed metabolic surgery because of the suspected direct, weight loss independent effect of bariatric procedures on the physiopathological mechanisms causing excess fat storage and insulin resistance. This review describes the standard procedures commonly performed and their specific outcomes on metabolic diseases in order to work towards more patient tailored treatment of obesity and to reduce side effects. Furthermore this review focuses on gaps in understanding the pathogenesis of obesity and its treatment with bariatric surgery. Surgery failures as well as new techniques are discussed and evaluated.

An evaluation of the knowledge of the surgical treatment of obesity among surgeons

INTRODUCTION

Surgical treatment of obesity is currently the only effective treatment option for patients with excess body weight, especially morbid obesity and diseases caused by it. There are no studies evaluating the knowledge of surgeons in the field of bariatric surgery.

AIM

To assess the knowledge of surgeons regarding bariatric surgery.

MATERIAL AND METHODS

An anonymous questionnaire was conducted among 143 surgeons in 2010-2011 during local educational conferences. The survey consisted of 10 questions dedicated to the fundamental problems of the surgical treatment of obesity.

RESULTS

Theoretical and practical knowledge connected to the so-called "epidemiological awareness" in the surgical treatment of obesity was possessed by 25% of the respondents. Knowledge of surgical techniques is known to most surgeons. Reducing the "oncological risk" after bariatric surgery is known to only 27% of surgeons. Almost 80% of surgeons indicated a necessity of their further education regarding the surgical treatment of obesity.

CONCLUSIONS

Knowledge of Polish general surgeons in the surgical treatment of obesity is not high, with a high number of surgeons who possess knowledge of the operating technique, whereas only a quarter have a basic knowledge of the indication for surgical treatment. Most surgeons who participated in our study are awaiting educational programmes focused on this issue.

Obesity and Black Women: Special Considerations Related to Genesis and Therapeutic Approaches

Black women in the United States are disproportionately affected by obesity, with almost two-thirds considered obese based on body mass index. Obesity has been directly linked to cardiovascular morbidity and mortality in black women. Therefore, understanding contributors to the genesis of obesity in black women is imperative. While biologic differences likely result in varying obesity prevalence across racial/ethnic groups, behaviors such as post-partum weight retention and limited leisure-time physical activity, may especially contribute to obesity in black women. Black women also appear to be particularly susceptible to cultural, psychosocial, and environmental factors that can promote weight gain. Therapeutic interventions are being tailored to specifically address these social determinants of health and to foster lifestyle modification; however, more work is needed to understand barriers to behavior change for black women. Knowledge gaps also remain in identifying mechanisms by which pharmacologic and surgical treatments for obesity modify cardiovascular risk in black women.

'Adiposopathy' and cardiovascular disease: the benefits of bariatric surgery

PURPOSE OF REVIEW

Obesity is an independent risk factor for cardiovascular disease (CVD) and promotes CVD risk factors. Bariatric surgery has gained much favor because it ameliorates CVD. This review examines the current evidence for the mechanism behind this, which is currently thought to occur in part by reduction of adiposopathy, or dysfunctional adipose tissue, through modulation of adipokine secretion.

RECENT FINDINGS

Increased visceral fat in obesity leads to adiposopathy, due to the chronic inflammation present in this tissue. Bariatric surgery causes weight loss as well as reduction in insulin resistance, hypertension, dyslipidemia, cardiac hypertrophy, and mortality. It also causes changes in the adipokines adiponectin, leptin, and C-reactive protein, but not in tumor necrosis factor-α. These changes contribute to improved CVD risk, possibly through decrease of chronic inflammation.

SUMMARY

The modulations in adipokine secretion that occur after bariatric surgery are involved with reduction in CVD risk factors, CVD, and CV mortality. On the basis of the known anti-inflammatory effects of adiponectin and the pro-inflammatory effects of leptin and CRP, reduction in chronic inflammation associated with less visceral fat after surgery may contribute to the reduction in CVD. This may promote improvement of endothelial dysfunction and insulin resistance. Further work is necessary to explore these relationships.