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

Cardiometabolic comorbidities and complications of obesity and chronic kidney disease (CKD)

Obesity and chronic kidney disease are two ongoing progressive clinical pandemics of major public health and clinical care significance. Because of their growing prevalence, chronic indolent course and consequent complications both these conditions place significant burden on the health care delivery system especially in developed countries like the United States. Beyond the chance coexistence of both of these conditions in the same patient based on high prevalence it is now apparent that obesity is associated with and likely has a direct causal role in the onset, progression and severity of chronic kidney disease. The causes and underlying pathophysiology of this are myriad, complicated and multi-faceted. In this review, continuing the theme of this special edition of the journal on " The Cross roads between Endocrinology and Nephrology" we review the epidemiology of obesity related chronic kidney disease (ORCKD), and its various underlying causes and pathophysiology. In addition, we delve into the consequent comorbidities and complications associated with ORCKD with particular emphasis on the cardio metabolic consequences and then review the current body of evidence for available strategies for chronic kidney disease modulation in ORCKD as well as the potential unique role of weight reduction and management strategies in its improvement and risk reduction.

Randomized Trial of Effect of Bariatric Surgery on Blood Pressure After 5 Years

BACKGROUND

Obesity represents a major obstacle for controlling hypertension, the leading risk factor for cardiovascular mortality.

OBJECTIVES

The purpose of this study was to determine the long-term effects of bariatric surgery on hypertension control and remission.

METHODS

We conducted a randomized clinical trial with subjects with obesity grade 1 or 2 plus hypertension using at least 2 medications. We excluded subjects with previous cardiovascular events and poorly controlled type 2 diabetes. Subjects were assigned to Roux-en-Y gastric bypass (RYGB) combined with medical therapy (MT) or MT alone. We reassessed the original primary outcome (reduction of at least 30% of the total antihypertensive medications while maintaining blood pressure levels <140/90 mm Hg) at 5 years. The main analysis followed the intention-to-treat principle.

RESULTS

A total of 100 subjects were included (76% women, age 43.8 ± 9.2 years, body mass index: 36.9 ± 2.7 kg/m2). At 5 years, body mass index was 36.40 kg/m2 (95% CI: 35.28-37.52 kg/m2) for MT and 28.01 kg/m2 (95% CI: 26.95-29.08 kg/m2) for RYGB (P < 0.001). Compared with MT, RYGB promoted a significantly higher rate of number of medications reduction (80.7% vs 13.7%; relative risk: 5.91; 95% CI: 2.58-13.52; P < 0.001) and the mean number of antihypertensive medications was 2.97 (95% CI: 2.33-3.60) for MT and 0.80 (95% CI: 0.51-1.09) for RYGB (P < 0.001). The rates of hypertension remission were 2.4% vs 46.9% (relative risk: 19.66; 95% CI: 2.74-141.09; P < 0.001). Sensitivity analysis considering only completed cases revealed consistent results. Interestingly, the rate of apparent resistant hypertension was lower after RYGB (0% vs 15.2%).

CONCLUSIONS

Bariatric surgery represents an effective and durable strategy to control hypertension and related polypharmacy in subjects with obesity. (GAstric bypass to Treat obEse Patients With steAdy hYpertension [GATEWAY]; NCT01784848).

Hypertension management in patients with cardiovascular comorbidities

Arterial hypertension is a leading cause of death globally. Due to ageing, the rising incidence of obesity, and socioeconomic and environmental changes, its incidence increases worldwide. Hypertension commonly coexists with Type 2 diabetes, obesity, dyslipidaemia, sedentary lifestyle, and smoking leading to risk amplification. Blood pressure lowering by lifestyle modifications and antihypertensive drugs reduce cardiovascular (CV) morbidity and mortality. Guidelines recommend dual- and triple-combination therapies using renin–angiotensin system blockers, calcium channel blockers, and/or a diuretic. Comorbidities often complicate management. New drugs such as angiotensin receptor-neprilysin inhibitors, sodium–glucose cotransporter 2 inhibitors, glucagon-like peptide-1 receptor agonists, and non-steroidal mineralocorticoid receptor antagonists improve CV and renal outcomes. Catheter-based renal denervation could offer an alternative treatment option in comorbid hypertension associated with increased sympathetic nerve activity. This review summarises the latest clinical evidence for managing hypertension with CV comorbidities.

Hypertension Related to Obesity: Pathogenesis, Characteristics and Factors for Control

The World Health Organization (WHO) refers to obesity as abnormal or excessive fat accumulation that presents a health risk. Obesity was first designated as a disease in 2012 and since then the cost and the burden of the disease have witnessed a worrisome increase. Obesity and hypertension are closely interrelated as abdominal obesity interferes with the endocrine and immune systems and carries a greater risk for insulin resistance, diabetes, hypertension, and cardiovascular disease. Many factors are at the interplay between obesity and hypertension. They include hemodynamic alterations, oxidative stress, renal injury, hyperinsulinemia, and insulin resistance, sleep apnea syndrome and the leptin-melanocortin pathway. Genetics, epigenetics, and mitochondrial factors also play a major role. The measurement of blood pressure in obese patients requires an adapted cuff and the search for other secondary causes is necessary at higher thresholds than the general population. Lifestyle modifications such as diet and exercise are often not enough to control obesity, and so far, bariatric surgery constitutes the most reliable method to achieve weight loss. Nonetheless, the emergence of new agents such as Semaglutide and Tirzepatide offers promising alternatives. Finally, several molecular pathways are actively being explored, and they should significantly extend the treatment options available.

Changes in Antihypertensive Medication Following Bariatric Surgery

Obesity is a leading cause of hypertension (i.e., high blood pressure [BP]). While hypertension can be managed with antihypertensive medication, substantial weight loss can also lower BP, reducing the need for antihypertensive medication. Articles in this review (n = 60) presented data on antihypertensive medication use among adults pre- and postoperatively. Roux-en-Y gastric bypass was the most studied surgical approach followed by Laparoscopic Sleeve Gastrectomy. Antihypertensive medication was discontinued in a large proportion of patients after surgery, and the mean number of antihypertensive medications decreased by approximately one. In almost a third of the studies, over 75% of participants experienced hypertension remission. All articles aside from two reported a decrease in systolic BP, with about 40% reporting a decrease of ≥ 10 mm Hg.

Remission, relapse, and risk of major cardiovascular events after metabolic surgery in persons with hypertension: A Swedish nationwide registry-based cohort study

BACKGROUND

Several studies have shown that metabolic surgery is associated with remission of diabetes and hypertension. In terms of diabetes, factors such as duration, insulin use, weight loss, and age have been shown to contribute to the likelihood of remission. Such factors have not been determined for hypertension. The aim of this study was to evaluate factors associated with the remission and relapse of hypertension after metabolic surgery, as well as the risk for major adverse cardiovascular event (MACE) and mortality in patients with and without remission.

METHODS AND FINDINGS

All adults who underwent metabolic surgery between January 2007 and June 2016 were identified in the nationwide Scandinavian Obesity Surgery Registry (SOReg). Through cross-linkage with the Swedish Prescribed Drug Register, Patient Register, and Statistics Sweden, individual data on prescriptions, inpatient and outpatient diagnoses, and mortality were retrieved. Of the 15,984 patients with pharmacologically treated hypertension, 6,286 (39.3%) were in remission at 2 years. High weight loss and male sex were associated with higher chance of remission, while duration, number of antihypertensive drugs, age, body mass index (BMI), cardiovascular disease, and dyslipidemia were associated with lower chance. After adjustment for age, sex, BMI, comorbidities, and education, the cumulative probabilities of MACEs (2.8% versus 5.7%, adjusted odds ratio (OR) 0.60, 95% confidence interval (CI) 0.47 to 0.77, p < 0.001) and all-cause mortality (4.0% versus 8.0%, adjusted OR 0.71, 95% CI 0.57 to 0.88, p = 0.002) were lower for patients being in remission at 2 years compared with patients not in remission, despite relapse of hypertension in 2,089 patients (cumulative probability 56.3%) during 10-year follow-up. The main limitations of the study were missing information on nonpharmacological treatment for hypertension and the observational study design.

CONCLUSIONS

In this study, we observed an association between high postoperative weight loss and male sex with better chance of remission, while we observed a lower chance of remission depending on disease severity and presence of other metabolic comorbidities. Patients who achieved remission had a halved risk of MACE and death compared with those who did not. The results suggest that in patients with severe obesity and hypertension, metabolic surgery should not be delayed.

Obesity Management and Chronic Kidney Disease

Obesity is one of the risk factors for the development and progression of chronic kidney disease (CKD). Several studies have shown the association between increased body mass index and kidney function decline. Obesity leads to CKD directly by acting as an independent risk factor and indirectly through increasing risks for diabetes, hypertension, and atherosclerosis, a group of well-established independent risk factors for CKD. Alterations in renal hemodynamics, inflammation, and in hormones and growth factors results in hyperfiltration injury and focal segmental glomerulosclerosis. In recent years, many studies have shown that the gut microbiome may play a role in the pathogenesis of obesity. Dysbiosis has been noted in obese subjects in both human and animal studies. Changes in the gut microbiome in obese patients promote weight gain by effectively extracting energy from diet, and induction of low-grade inflammation. Evidence also points to the role of inflammation within the adipose tissue in obesity as a key factor in the pathogenesis of obesity-related complications. Thus, obesity is the net result of complex interactions between behavioral, genetic, and environmental factors. In terms of management, conservative approaches are often the first option, but they often are unsuccessful in achieving and/or maintaining weight loss, particularly in severe obesity. Consequently, nonmedical management with bariatric surgery is the most effective treatment option for morbid obesity and has shown mitigation of multiple risk factors for the progression of CKD. The most frequently performed interventions are vertical sleeve gastrectomy and Roux-en-Y gastric bypass. Studies have shown that bariatric surgery is associated with beneficial effects on CKD by mitigating its risk factors by weight loss, reducing insulin resistance, hemoglobin A1c, and proteinuria, in addition to positive long-term outcomes. Because of the epidemic of obesity, the prevalence of obesity in kidney transplant recipients also is increasing. The maximal body mass index (BMI) threshold for kidney transplantation is not clear. The Organ Procurement Transplant Network/Scientific Registry of Transplant Recipients 2019 annual data report showed that the proportion of kidney transplant recipient candidates with a BMI of 30 kg/m² or greater is increasing steadily. Morbid obesity is linked to adverse graft outcomes including delayed graft function, primary nonfunction, and decreased graft survival. Obesity is also an independent risk factor for cardiovascular death in kidney transplant recipients, suggesting that these patients should not be excluded from transplantation based on their BMI because transplantation is associated with lower mortality compared with dialysis. However, many centers exclude obese patients (with different BMI cut-off values) from transplantation to avoid postoperative complications. To minimize the surgical complications of kidney transplantation in obese patients, our center has adopted the robot-assisted kidney transplantation procedure. Our data show that this approach is comparable with historical nonobese controls in the United Network for Organ Sharing database in terms of patient and graft survival. Another surgical option for this group of patients at our center is a combined robotic sleeve gastrectomy and robotic-assisted kidney transplant. In a recent study, this approach showed promising results in terms of weight loss, patient survival, and graft survival, and might become more common in the future.

Weight-Loss Strategies for Prevention and Treatment of Hypertension: A Scientific Statement From the American Heart Association

Hypertension is a major risk factor for cardiovascular and renal diseases in the United States and worldwide. Obesity accounts for much of the risk for primary hypertension through several mechanisms, including neurohormonal activation, inflammation, and kidney dysfunction. As the prevalence of obesity continues to increase, hypertension and associated cardiorenal diseases will also increase unless more effective strategies to prevent and treat obesity are developed. Lifestyle modification, including diet, reduced sedentariness, and increased physical activity, is usually recommended for patients with obesity; however, the long-term success of these strategies for reducing adiposity, maintaining weight loss, and reducing blood pressure has been limited. Effective pharmacotherapeutic and procedural strategies, including metabolic surgeries, are additional options to treat obesity and prevent or attenuate obesity hypertension, target organ damage, and subsequent disease. Medications can be useful for short- and long-term obesity treatment; however, prescription of these drugs is limited. Metabolic surgery is effective for producing sustained weight loss and for treating hypertension and metabolic disorders in many patients with severe obesity. Unanswered questions remain related to the mechanisms of obesity-related diseases, long-term efficacy of different treatment and prevention strategies, and timing of these interventions to prevent obesity and hypertension-mediated target organ damage. Further investigation, including randomized controlled trials, is essential to addressing these questions, and emphasis should be placed on the prevention of obesity to reduce the burden of hypertensive cardiovascular and kidney diseases and subsequent mortality.

Bariatric Surgery and Hypertension

A clear pathogenetic association exists between obesity and arterial hypertension, becoming even more evident in subjects with severe obesity. Bariatric surgery has proved to be the most effective treatment for severe obesity, with its benefits going beyond weight loss. The present review aimed to determine the effects of bariatric surgery on arterial hypertension evident in short- and long-term follow-ups. Moreover, the differences between surgical techniques regarding hypertension remission are described as well as the possible pathophysiologic mechanisms involved. In addition, the effects of bariatric surgery beyond blood pressure normalization are also analyzed, including those on target organs and cardiovascular morbidity and mortality.

Characteristics and resolution of hypertension in obese African American bariatric cohort

Weight reduction continues to be first-line therapy in the treatment of hypertension (HTN). However, the long-term effect of bariatric malabsorptive surgical techniques such as Roux-en-Y Gastric Bypass (RYGB) surgery in the management of hypertension (HTN) is less clear. African Americans (AA) are disproportionately affected by obesity and hypertension and have inconsistent outcomes after bariatric surgery (BS). Despite a plethora of bariatric literature, data about characteristics of a predominantly AA bariatric hypertensive cohort including hypertension in obese (HIO) are scarce and underreported. The aims of this study were, (1) to describe the preoperative clinical characteristics of HIO with respect to HTN status and age, and (2) to identify predictors of HTN resolution one year after RYGB surgery in an AA bariatric cohort enrolled at the Howard University Center for Wellness and Weight Loss Surgery (HUCWWS). In the review of 169 AA bariatric patients, the average BMI was 48.50 kg/m² and the average age was 43.86 years. Obese hypertensive patients were older (46 years vs. 37.89 years; p < .0001); had higher prevalence of diabetes mellitus (DM, 43.09% vs. 10.87%; p < .0001) and dyslipidemia (38.2% vs. 13.04%; p 0.002). Hypertensive AA who were taking ≥ 2 antihypertensive medications prior to RYGB were 18 times less likely to experience HTN resolution compared to hypertensive AA taking 0–1 medications, who showed full or partial response. Also, HIO was less likely to resolve after RYGB surgery in patients who needed ≥ 2 antihypertensive medications prior to surgical intervention.

Roux-en-Y gastric bypass and sleeve gastrectomy for obesity-associated hypertension

Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) reduce blood pressure (BP) in obese patients with hypertension (HTN). We compared the effect of RYGB and SG on BP in obese patients with HTN at a large-volume, private bariatric surgery center using a propensity score analysis. The measurement and management of BP were exclusively left to the patient's provider without any involvement of Tulane investigators. At month 1, RYGB and SG equally decreased: (1) mean body weight: 12.7 vs 13.2 kg (p=not significant (NS)) (2) systolic/diastolic BP: 8.5/5.3 vs 8.0/4.2 mm Hg (p=NS) and (3) average number of antihypertensive medications from 1.5 to 0.8 and from 1.6 to 0.6 per patient (p=NS). From month 1 to 12, BP remained unchanged after RYGB but tended to increase from month 6 to 12 after SG. Remission of HTN occurred in 52% and 44% of patients after RYGB and SG. In contrast to the full effect of RYGB and SG on BP at 1 month, body weight decreases steadily over 12 months after RYGB and SG. In conclusion, early after surgery, RYGB and SG equally reduce BP in obese patients with HTN. Thereafter, RYGB has a more sustained effect on BP than SG.

Effect of bariatric surgery on natriuretic peptide levels: a systematic review and meta-analysis

The effect of bariatric surgery on natriuretic peptide levels in patients with obesity is unclear. The purpose of this study was to conduct a systematic review and meta-analysis to determine the effect of bariatric surgery on BNP and NT-proBNP levels. MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched to February 2020. Primary outcomes included change in NT-proBNP or BNP levels following bariatric surgery and change in weight and body mass index (BMI). Secondary outcomes included change in blood pressure, echocardiographic findings, and heart failure symptoms. MINORS tool was used to assess quality of evidence. Twelve studies with 622 patients were included. Most patients underwent Roux-en-Y gastric bypass (RYGB) (70.5%). Mean absolute reduction in BMI was 23%. NT-proBNP levels increased significantly from baseline at 6 months (mean difference (MD) 53.67 pg/mL; 95% CI, 28.72-78.61; P = <0.001, I2 = 99%; 8 studies) and 12 months (MD 51.16 pg/mL; 95% CI, 20.46-81.86; P = 0.001, I2 = 99%; 8 studies) post-bariatric surgery. BNP levels also increased significantly at 6 months (MD 17.57 pg/mL; 95% CI, 7.62-27.51; P <0.001, I2 = 95%; 4 studies). Systolic and diastolic blood pressure decreased significantly 12 months after surgery. Studies measuring echocardiographic findings saw improvement in LV mass and E/A ratio, but no significant change in ejection fraction. Bariatric surgery is associated with increased natriuretic peptide levels in the absence of deteriorating cardiac function, and may be associated with improved cardiac and metabolic function after the procedure.

Three-Year Outcomes of Bariatric Surgery in Patients With Obesity and Hypertension : A Randomized Clinical Trial

BACKGROUND

Midterm effects of bariatric surgery on patients with obesity and hypertension remain uncertain.

OBJECTIVE

To determine the 3-year effects of Roux-en-Y gastric bypass (RYGB) on blood pressure (BP) compared with medical therapy (MT) alone.

DESIGN

Randomized clinical trial. (ClinicalTrials.gov: NCT01784848).

SETTING

Investigator-initiated study at Heart Hospital (HCor), São Paulo, Brazil.

PARTICIPANTS

Patients with hypertension receiving at least 2 medications at maximum doses or more than 2 medications at moderate doses and with a body mass index (BMI) between 30.0 and 39.9 kg/m² were randomly assigned (1:1 ratio).

INTERVENTION

RYGB plus MT or MT alone.

MEASUREMENTS

The primary outcome was at least a 30% reduction in total number of antihypertensive medications while maintaining BP less than 140/90 mm Hg. Key secondary outcomes were number of antihypertensive medications, hypertension remission, and BP control according to current guidelines (<130/80 mm Hg).

RESULTS

Among 100 patients (76% female; mean BMI, 36.9 kg/m² [SD, 2.7]), 88% from the RYGB group and 80% from the MT group completed follow-up. At 3 years, the primary outcome occurred in 73% of patients from the RYGB group compared with 11% of patients from the MT group (relative risk, 6.52 [95% CI, 2.50 to 17.03]; P < 0.001). Of the randomly assigned participants, 35% and 31% from the RYGB group and 2% and 0% from the MT group achieved BP less than 140/90 mm Hg and less than 130/80 mm Hg without medications, respectively. Median (interquartile range) number of medications in the RYGB and MT groups at 3 years was 1 (0 to 2) and 3 (2.8 to 4), respectively (P < 0.001). Total weight loss was 27.8% and -0.1% in the RYGB and MT groups, respectively. In the RYGB group, 13 patients developed hypovitaminosis B₁₂ and 2 patients required reoperation.

LIMITATION

Single-center, nonblinded trial.

CONCLUSION

RYGB is an effective strategy for midterm BP control and hypertension remission, with fewer medications required in patients with hypertension and obesity.

PRIMARY FUNDING SOURCE

Ethicon, represented in Brazil by Johnson & Johnson do Brasil.

Metabolic bariatric surgery as a treatment for obstructive sleep apnea hypopnea syndrome: review of the literature and potential mechanisms

Obstructive sleep apnea hypopnea syndrome (OSAHS) is closely related to obesity and can cause multiple organs and systems damage. Metabolic bariatric surgery (MBS) is presently the only long-term effective treatment and an important strategy for severely obese population, which also provides a novel therapeutic for obese patients with OSAHS, especially in patients with poor continuous positive air pressure (CPAP) adherence. To date, the resolution mechanism of OSAHS in obese patients after MBS has not been fully clarified. In addition, there is no specific metabolic bariatric surgical treatment of OSAHS guidelines. Therefore, this review provides an update on the relationship between OSAHS and MBS for highlighting the importance of weight loss strategies for obese patients with OSAHS.

The Short-Term Effects of Roux-en-Y Gastric Bypass on Renal Excretion of Sodium and Its Association with Blood Pressure

INTRODUCTION

Bariatric surgery has been shown to be effective in reducing weight and has benefits, such as lowering blood pressure. An increase in urinary sodium excretion has been suggested as a possible mechanism. This study explored changes in sodium excretion and their correlation with blood pressure after Roux-en-Y gastric bypass.

MATERIALS AND METHODS

This study was conducted on 28 obese participants with body mass index (BMI) of 44.54 ± 7.81 kg/m² who underwent gastric bypass. Before surgery and at the third and sixth months after gastric bypass, blood pressure, urinary sodium concentration, 24-hour (24-h) urinary sodium excretion, and fractional excretion of sodium were evaluated. In addition, serum sodium and potassium levels were determined. Nonparametric tests were used to analyze the data.

RESULTS

Blood pressure decreased after surgery and remained at low levels over the 3- and 6-month periods. The urinary sodium concentration increased at 3 months after surgery; however, the 24-h urinary sodium excretion and urine volume decreased. Interestingly, although some associations between variables were observed, significant correlations between the 24-h urinary sodium excretion and the systolic, diastolic, and mean blood pressures were found. In addition, the urine volume was higher in the sixth month than in the third month following surgery.

CONCLUSIONS

In the months immediately following surgery, a low-salt and low-volume diet favors decreases in urine volume and 24-h urinary sodium excretion. In addition, in the sixth month after surgery, an association between blood pressure and 24-h urinary sodium excretion was observed.

Bariatric Surgery for Resistant Hypertension: Working in Progress!

PURPOSE OF REVIEW

To discuss the recent evidence pointing the benefits of the bariatric surgery on blood pressure control in patients with obesity and hypertension. Particular focus is devoted to discuss the potential impact on resistant hypertension.

RECENT FINDINGS

Growing evidence suggest that bariatric surgery promotes not only a significant reduction in the anti-hypertensive medication while maintained blood pressure control but also a significant proportion of hypertension remission as compared to the usual care. In a sub-analysis of the GATEWAY trial using both office and 24-h ambulatory blood pressure monitoring, the prevalence of resistant hypertension significantly decreased after 12 months in the surgical group whereas the numbers remained stable in the control group. Despite the lack of robust evidence, preliminary findings underscore the strong need to explore the potential role of bariatric surgery on resistant hypertension in patients with obesity. This statement is justified not only for the burden of obesity in this scenario but also for the unmet demands in managing resistant hypertension appropriately by multiple drug-therapy or the lack of real utility of procedures like renal denervation and carotid baroreflex activation.

Characterization of the renal cortical transcriptome following Roux-en-Y gastric bypass surgery in experimental diabetic kidney disease

INTRODUCTION

Roux-en-Y gastric bypass surgery (RYGB) reduces albuminuria and the long-term incidence of end-stage renal disease in patients with obesity and diabetes. Preclinical modeling in experimental diabetic kidney disease demonstrates that improvements in glomerular structure likely underpin these findings.

RESEARCH DESIGN AND METHODS

In adult male Zucker diabetic fatty (ZDF) rats, we profiled the effect of RYGB on weight and metabolic control as well biochemical, structural and ultrastructural indices of diabetic renal injury. Furthermore, we sequenced the renal cortical transcriptome in these rats and used bioinformatic pathway analyses to characterize the transcriptional alterations governing the renal reparative response to RYGB.

RESULTS

In parallel with improvements in weight and metabolic control, RYGB reduced albuminuria, glomerulomegaly, podocyte stress and podocyte foot process effacement. Pathway analysis of RYGB-induced transcriptomic changes in the renal cortex highlighted correction of disease-associated alterations in fibrosis, inflammation and biological oxidation pathways. RYGB reversed disease-associated changes in the expression of transforming growth factor (TGF)-β superfamily genes that strongly correlated with improvements in structural measures of glomerulopathy.

CONCLUSIONS

Improved glomerular structure in ZDF rats following RYGB is underpinned by pathway level changes, including interruption of the TGF-β-driven early profibrotic programme. Our data provide an important layer of experimental support for clinical evidence demonstrating that RYGB arrests renal damage in patients with obesity and type 2 diabetes.

Obesity, Hypertension, and Bariatric Surgery

PURPOSE OF REVIEW

Obesity increases the risk of hypertension. However, blood pressure decreases before any significant loss of body weight after bariatric surgery. We review the mechanisms of the temporal dissociation between blood pressure and body weight after bariatric surgery.

RECENT FINDINGS

Restrictive and bypass bariatric surgery lower blood pressure and plasma leptin levels within days of the procedure in both hypertensive and normotensive morbidly obese patients. Rapidly decreasing plasma leptin levels and minimal loss of body weight point to reduced sympathetic nervous system activity as the underlying mechanism of rapid blood pressure decline after bariatric surgery. After the early rapid decline, blood pressure does not decrease further in patients who, while still obese, experience a steady loss of body weight for the subsequent 12 months. The divergent effects of bariatric surgery on blood pressure and body weight query the role of excess body weight in the pathobiology of the obesity phenotype of hypertension. The decrease in blood pressure after bariatric surgery is moderate and independent of body weight. The lack of temporal relationship between blood pressure reduction and loss of body weight for 12 months after sleeve gastrectomy questions the nature of the mechanisms underlying obesity-associated hypertension.

Changes in Central 24-h Ambulatory Blood Pressure and Hemodynamics 12 Months After Bariatric Surgery: the BARIHTA Study

BACKGROUND

Weight loss is associated to blood pressure (BP) reduction in obese patients. There is no information on central 24-h BP changes after bariatric surgery (BS).

METHODS AND RESULTS

In this study, we analyzed changes in 24-h BP 12 months following BS, with intermediate evaluations at 1, 3, and 6 months, in severely obese adults. The primary endpoint was aortic (central) 24-h systolic BP changes. Circadian BP patterns and hypertension resolution were also assessed. As secondary endpoints, we analyze changes in central 24-h diastolic BP as well as in all office and ambulatory peripheral BP parameters. Obese adults scheduled for BS as routine clinical care were recruited. We included 62 patients (39% with hypertension, 77% women, body mass index, 42.6 ± 5.5 kg/m²). Reduction in body weight was mean (IQR) 30.5% (26.2-34.4) 1 year after BS. Mean (95% CI) change in central 24-h systolic BP was - 3.1 mmHg (- 5.5 to - 0.7), p = 0.01 after adjustment for age, sex, and baseline hypertensive status. BP parameter changes were different between normotensives and hypertensives. Mean (95% CI) change in central 24-h systolic BP was - 5.2 mmHg (- 7.7 to - 2.7), p < 0.001, in normotensives and - 0.5 mmHg (- 5.1 to 4.0), p = 0.818, in hypertensives. There was a remission of hypertension in 48% of patients. Most patients had a reduced dipping pattern, similarly at baseline and 12 months after BS.

CONCLUSIONS

Among patients with severe obesity, there was a substantial central 24-h systolic BP decrease 12 months following BS. Importantly, this change was observed in those patients with normal BP at baseline.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03115502.

Alteration Pattern of Taste Perception After Bariatric Surgery: a Systematic Review of Four Taste Domains

BACKGROUND

Efforts continue to understand the underlying mechanism of weight loss after bariatric surgery. Taste perception has shown to be a contributing factor. However, the alteration pattern in different taste domains and among bariatric procedures has not been sufficiently investigated.

OBJECTIVES

To study the alteration pattern in the perception of four taste domains after different bariatric procedures.

SETTINGS

Private Research Institute, USA.

METHODS

A systematic review was conducted to pool available data in the literature on post-operative changes in the perception of sensitivity to four taste domains after Roux-en-Y gastric bypass (RYGB), laparoscopic sleeve gastrectomy (LSG), and adjustable gastric banding (AGB).

RESULTS

Our study showed that bariatric surgery is associated with significant change in sensitivity to all four taste domains especially salt taste, sweetness, and sourness. LSG patients showed an increased sensitivity to all four taste domains. However, RYGB patients had a variable alteration pattern of taste perception but more commonly a decreased sensitivity to sweetness and an increased sensitivity to salt taste and sourness. Additionally, AGB patients had a decreased sensitivity to sweetness, salt taste, and sourness.

CONCLUSION

Bariatric surgery is associated with taste change in a way which results in less preference for high-calorie food and possibly reduced calorie intake. This may explain one of the mechanisms by which bariatric surgery produces weight loss. However, data are heterogeneous, the potential effect dilutes over time, and the alteration varies significantly between different procedures.

Obesity-related hypertension: a review of pathophysiology, management, and the role of metabolic surgery

Obesity is a significant public health challenge worldwide and is inextricably linked to adverse cardiovascular outcomes. The relationship between excess adiposity and increased blood pressure is well established, and it is estimated that obesity accounts for 65-78% of cases of primary hypertension. The mechanisms through which obesity causes hypertension are complex and include sympathetic nervous system overactivation, stimulation of the renin-angiotensin-aldosterone system, alterations in adipose-derived cytokines, insulin resistance, and structural and functional renal changes. Weight loss is the primary goal of treatment for obesity-related hypertension, although few individuals achieve success with nonpharmacological management alone. Specific considerations apply when selecting the most appropriate pharmacological therapy for obese hypertensive patients. Metabolic surgery has proved to be the most effective means of ensuring substantial and sustained weight loss and has also been shown to confer beneficial effects in type 2 diabetes mellitus. Increasing evidence suggests that metabolic surgery may also be an effective treatment for obesity-related hypertension, although prospective data on long-term blood pressure outcomes are awaited. This review will discuss the pathophysiological mechanisms that link obesity with hypertension and will provide an overview of treatment strategies, with a focus on metabolic surgery.

Weight Loss and Hypertension in Obese Subjects

Arterial hypertension is strongly related to overweight and obesity. In obese subjects, several mechanisms may lead to hypertension such as insulin and leptin resistance, perivascular adipose tissue dysfunction, renal impairment, renin-angiotensin-aldosterone-system activation and sympathetic nervous system activity. Weight loss (WL) seems to have positive effects on blood pressure (BP). The aim of this review was to explain the mechanisms linking obesity and hypertension and to evaluate the main studies assessing the effect of WL on BP. We analysed studies published in the last 10 years (13 studies either interventional or observational) showing the effect of WL on BP. Different WL strategies were taken into account-diet and lifestyle modification, pharmacological intervention and bariatric surgery. Although a positive effect of WL could be identified in each study, the main difference seems to be the magnitude and the durability of BP reduction over time. Nevertheless, further follow-up data are needed: there is still a lack of evidence about long term effects of WL on hypertension. Hence, given the significant results obtained in several recent studies, weight management should always be pursued in obese patients with hypertension.

Pros and cons of Roux en-Y gastric bypass surgery in obese patients with type 2 diabetes

INTRODUCTION

The worldwide prevalence of obesity and type 2 diabetes (T2D) constitutes an epidemic that is a threat to public health. Bariatric surgery, including Roux en-Y gastric bypass (RYGB), is currently the most effective treatment to induce long-term weight loss and remission of co-morbid conditions. Surgery, however, comes with an added risk of complications, highlighting the need to understand the comparative effectiveness and risks of surgical versus conventional approaches to the treatment of obesity and T2D.

AREAS COVERED

Positive and negative outcomes of RYGB surgery in patients with T2D are assessed, with a primary focus on RYGB surgery versus standard non-surgical treatment of obese patients with T2D in randomized clinical trials or high-quality observational cohorts. Searches were conducted in the PubMed database up to 11 April 2019 for relevant studies.

EXPERT OPINION

High-level evidence reveals that RYGB ameliorates the clinical manifestations of T2D to a significantly higher degree than medical therapy. Postoperative incidence of beneficial effects and complications, however, differ across subgroups of patients with different preoperative characteristics. Key knowledge gaps, particularly on long-term complications, microvascular- and macrovascular events, and mortality should be addressed, so treatment with RYGB can be applied in an individualized approach to maximize benefits and minimize complications.

Obesity and cardiovascular risk: a call for action from the European Society of Hypertension Working Group of Obesity, Diabetes and the High-risk Patient and European Association for the Study of Obesity: part A: mechanisms of obesity induced hypertension, diabetes and dyslipidemia and practice guidelines for treatment

: Obesity is a key factor for cardiovascular diseases and complications. Obesity is associated with hypertension, dyslipidemia and type II diabetes, which are the major predictors of cardiovascular disease in the future. It predisposes for atrial fibrillation, heart failure, sudden cardiac death, renal disease and ischemic stroke that are the main causes of cardiovascular hospitalization and mortality. As obesity and the cardiovascular effects on the vessels and the heart start early in life, even from childhood, it is important for health policies to prevent obesity very early before the disease manifestation emerge. Key roles in the prevention are strategies to increase physical exercise, reduce body weight and to prevent or treat hypertension, lipids disorders and diabetes earlier and efficiently to prevent cardiovascular complications.Epidemiology and mechanisms of obesity-induced hypertension, diabetes and dyslipidemia will be reviewed and the role of lifestyle modification and treatment strategies in obesity will be updated and analyzed. The best treatment options for people with obesity, hypertension, diabetes and dyslipidemia will discussed.

Hypertension as a Metabolic Disorder and the Novel Role of the Gut

Purpose of Review

Hypertension is related to impaired metabolic homeostasis and can be regarded as a metabolic disorder. This review presents possible mechanisms by which metabolic disorders increase blood pressure (BP) and discusses the importance of the gut as a novel modulator of BP.

Recent Findings

Obesity and high salt intake are major risk factors for hypertension. There is a hypothesis of “salt-induced obesity”; i.e., high salt intake may tie to obesity. Heightened sympathetic nervous system (SNS) activity, especially in the kidney and brain, increases BP in obese patients. Adipokines, including adiponectin and leptin, and renin-angiotensin-aldosterone system (RAAS) contribute to hypertension. Adiponectin induced by a high-salt diet may decrease sodium/glucose cotransporter (SGLT) 2 expression in the kidney, which results in reducing BP. High salt can change secretions of adipokines and RAAS-related components. Evidence has been accumulating linking the gastrointestinal tract to BP. Glucagon-like peptide-1 (GLP-1) and ghrelin decrease BP in both rodents and humans. The sweet taste receptor in enteroendocrine cells increases SGLT1 expression and stimulates sodium/glucose absorption. Roux-en-Y gastric bypass improves glycemic and BP control due to reducing the activity of SGLT1. Na/H exchanger isoform 3 (NHE3) increases BP by stimulating the intestinal absorption of sodium. Gastrin functions as an intestinal sodium taste sensor and inhibits NHE3 activity. Intestinal mineralocorticoid receptors also regulate sodium absorption and BP due to changing ENaC activity. Gastric sensing of sodium induces natriuresis, and gastric distension increases BP. Changes in the composition and function of gut microbiota contribute to hypertension. A high-salt/fat diet may disrupt the gut barrier, which results in systemic inflammation, insulin resistance, and increased BP. Gut microbiota regulates BP by secreting vasoactive hormones and short-chain fatty acids. BP-lowering effects of probiotics and antibiotics have been reported. Bariatric surgery improves metabolic disorders and hypertension due to increasing GLP-1 secretion, decreasing leptin secretion and SNS activity, and changing gut microbiome composition. Strategies targeting the gastrointestinal system may be therapeutic options for improving metabolic abnormalities and reducing BP in humans.

Summary

SNS, brain, adipocytes, RAAS, the kidney, the gastrointestinal tract, and microbiota play important roles in regulating BP. Most notably, the gut could be a novel target for treatment of hypertension as a metabolic disorder.

Fat-Specific Protein 27 Regulation of Vascular Function in Human Obesity

Background Pathophysiological mechanisms that connect obesity to cardiovascular disease are incompletely understood. FSP27 (Fat-specific protein 27) is a lipid droplet-associated protein that regulates lipolysis and insulin sensitivity in adipocytes. We unexpectedly discovered extensive FSP27 expression in human endothelial cells that is downregulated in association with visceral obesity. We sought to examine the functional role of FSP27 in the control of vascular phenotype. Methods and Results We biopsied paired subcutaneous and visceral fat depots from 61 obese individuals (body mass index 44±8 kg/m2, age 48±4 years) during planned bariatric surgery. We characterized depot-specific FSP27 expression in relation to adipose tissue microvascular insulin resistance, endothelial function and angiogenesis, and examined differential effects of FSP27 modification on vascular function. We observed markedly reduced vasodilator and angiogenic capacity of microvessels isolated from the visceral compared with subcutaneous adipose depots. Recombinant FSP27 and/or adenoviral FSP27 overexpression in human tissue increased endothelial nitric oxide synthase phosphorylation and nitric oxide production, and rescued vasomotor and angiogenic dysfunction (P<0.05), while siRNA-mediated FSP27 knockdown had opposite effects. Mechanistically, we observed that FSP27 interacts with vascular endothelial growth factor-A and exerts robust regulatory control over its expression. Lastly, in a subset of subjects followed longitudinally for 12±3 months after their bariatric surgery, 30% weight loss improved metabolic parameters and increased angiogenic capacity that correlated positively with increased FSP27 expression (r=0.79, P<0.05). Conclusions Our data strongly support a key role and functional significance of FSP27 as a critical endogenous modulator of human microvascular function that has not been previously described. FSP27 may serve as a previously unrecognized regulator of arteriolar vasomotor capacity and angiogenesis which are pivotal in the pathogenesis of cardiometabolic diseases linked to obesity.

Comparison of Cardiovascular Benefits of Bariatric Surgery and Abdominal Lipectomy

PURPOSE OF REVIEW

The purpose of this review is to examine recent evidence supporting effectiveness of bariatric surgery and abdominal lipectomy as interventional strategies aimed at reduction in incidence of cardiovascular disease (CVD) and related morbidity and mortality in obese and metabolic syndrome patients.

RECENT FINDINGS

While several studies show reduction in CVD risk factors in patients who have undergone both the Roux-en-Y gastric bypass and sleeve gastrectomy, very few demonstrate actual improvements in cardiovascular function, or a decrease in CVD events or CVD-related mortality. Consequently, the cardiovascular benefits of the less invasive sleeve gastrectomy in comparison to the gastric bypass are also unclear. Striking new data on large patient samples demonstrate significant positive correlation between gastric bypass and CVD risk factor reduction only in patients who are diabetic or > 50 years of age at the time of surgery, with no significant differences in non-diabetic and younger patients and with significant side effects. On the other hand, a markedly less invasive removal of abdominal subcutaneous adipose tissue via lipectomy consistently and significantly improved CVD risk factors as well as cardiovascular function in the very few studies available. Overall, neither the potential nor the definitive cardiovascular benefits of either of the commonly used bariatric surgical or the various lipectomy procedures have been adequately explored. Future basic science and clinical studies have the opportunity to understand the mechanisms and long-term consequences of both approaches and develop personalized approaches with higher benefit to side effect ratios.

Impact of bariatric surgery on cardiovascular and renal complications of diabetes: a focus on clinical outcomes and putative mechanisms

INTRODUCTION

Cardiovascular and renal disease accounts for a substantial proportion of the morbidity and mortality associated with obesity and type 2 diabetes mellitus (T2DM). Bariatric surgery is associated with improved long-term cardiovascular and renal outcomes.

AREAS COVERED

All major case-control, cohort, and randomized controlled trial studies of bariatric surgery in adults with T2DM were screened and data on prespecified cardiovascular and renal outcomes collated. Bariatric surgery reduces all-cause mortality and risk of cardiovascular disease, albuminuria and progressive chronic kidney disease. Patients with poorer glycemic control and established microvascular disease preoperatively may stand to benefit the most from the surgical approach. Reduced sympathetic drive, remission of glomerular hypertension, enhanced natriuresis, gut microbiota shifts, reduced systemic and renal inflammation, improved lipoprotein profiles, and reductions in chronic cardiac remodeling may all be implicated.

EXPERT COMMENTARY

Ongoing RCTs of bariatric surgery selectively recruiting patients with class 1 obesity and established microvascular complications of diabetes will help to better characterize which subgroups of patients benefit most from this effective therapy.

Metabolic Effects of Bariatric Surgery

BACKGROUND

Obesity can be defined as a chronic subcortical brain disease, as there is an important neurophysiological component to its etiology based on changes in the functioning of those areas of the brain controlling food intake and reward. Extensive metabolic changes accompany bariatric surgery-based treatment of obesity. Consequently, the term “metabolic” surgery is being increasingly adopted in relation to the beneficial effects these procedures have on chronic diseases like type 2 diabetes.

CONTENT

In the present review, we focus on the key biochemical and physiological changes induced by metabolic surgery and highlight the beneficial effects accrued systemically with the use of an organ-based approach. Understanding the impact on and interactions between the gut, brain, adipose tissue, liver, muscle, pancreas, and kidney is key to understanding the sum of the metabolic effects of these operations.

SUMMARY

Further mechanistic studies are essential to assess the true potential of metabolic surgery to treat metabolic comorbidities of obesity beyond type 2 diabetes. Approaches that may mitigate the metabolic side effects of surgery also require attention. Understanding the positive impact of metabolic surgery on metabolic health may result in a wider acceptance of this intervention as treatment for metabolic, comorbid conditions.

Bariatric Surgery and Hypertension

Obesity continues to increase in prevalence worldwide. Hypertension has long been associated with obesity, and weight loss continues to be a first-line therapy in the treatment of hypertension. Lifestyle modification and pharmacologic therapy, however, often meet with treatment failure. Bariatric surgery continues to be the most successful approach to sustained weight loss. This review focuses on the underlying physiologic mechanisms of obesity-hypertension, and the impact of bariatric surgery on the treatment of hypertension. Current available literature on the physiologic mechanisms of obesity-hypertension, and the major trials, meta-analyses and systematic reviews of the impact of bariatric surgery procedures on hypertension are reviewed. Evidence suggests significant improvement in obesity-hypertension in patients who undergo surgical weight-reduction procedures. Malabsorptive techniques such as the Roux-en-Y gastric bypass or surgical resection techniques such as laparoscopic sleeve gastrectomy appear to offer superior results in regards to hypertension control over restrictive techniques such as Gastric Banding. Though long-term control of hypertension following surgery remains a concern, available follow-up post-operative data of up to 10 years suggests a sustained, if lessened, effect on hypertension control over time.

Effects of Bariatric Surgery in Obese Patients With Hypertension: The GATEWAY Randomized Trial (Gastric Bypass to Treat Obese Patients With Steady Hypertension)

BACKGROUND

Recent research efforts on bariatric surgery have focused on metabolic and diabetes mellitus resolution. Randomized trials designed to assess the impact of bariatric surgery in patients with obesity and hypertension are needed.

METHODS

In this randomized, single-center, nonblinded trial, we included patients with hypertension (using ≥2 medications at maximum doses or >2 at moderate doses) and a body mass index between 30.0 and 39.9 kg/m². Patients were randomized to Roux-en-Y gastric bypass plus medical therapy or medical therapy alone. The primary end point was reduction of ≥30% of the total number of antihypertensive medications while maintaining systolic and diastolic blood pressure <140 mm Hg and 90 mm Hg, respectively, at 12 months.

RESULTS

We included 100 patients (70% female, mean age 43.8±9.2 years, mean body mass index 36.9±2.7 kg/m2), and 96% completed follow-up. Reduction of ≥30% of the total number of antihypertensive medications while maintaining controlled blood pressure occurred in 41 of 49 patients from the gastric bypass group (83.7%) compared with 6 of 47 patients (12.8%) from the control group with a rate ratio of 6.6 (95% confidence interval, 3.1-14.0; P<0.001). Remission of hypertension was present in 25 of 49 (51%) and 22 of 48 (45.8%) patients randomized to gastric bypass, considering office and 24-hour ambulatory blood pressure monitoring, respectively, whereas no patient submitted to medical therapy was free of antihypertensive drugs at 12 months. A post hoc analysis for the primary end point considering the SPRINT (Systolic Blood Pressure Intervention Trial) target reached consistent results, with a rate ratio of 3.8 (95% confidence interval, 1.4-10.6; P=0.005). Eleven patients (22.4%) from the gastric bypass group and none in the control group were able to achieve SPRINT levels without antihypertensives. Waist circumference, body mass index, fasting plasma glucose, glycohemoglobin, low-density lipoprotein cholesterol, triglycerides, high-sensitivity C-reactive protein, and 10-year Framingham risk score were lower in the gastric bypass than in the control group.

CONCLUSIONS

Bariatric surgery represents an effective strategy for blood pressure control in a broad population of patients with obesity and hypertension.

CLINICAL TRIAL REGISTRATION

URL: https://clinicaltrials.gov. Unique identifier: NCT01784848.

The Role of Metabolic Surgery on Blood Pressure Control

Obesity and hypertension are growing epidemics in the modern world. Lifestyle changes and medical treatment for obesity have disappointing long-term results and albeit drugs for hypertension are usually very effective, the necessity of multiple pills and frequent side effects make the adherence to treatment a huge challenge for healthcare systems. Bariatric/metabolic surgery is a very effective treatment and an exponential number of studies have been showing its positive impact beyond weight loss, mainly on type 2 diabetes. There is also growing evidence suggesting that bariatric/metabolic surgery is associated with reduced incidence of cardiovascular events, but the impact on hypertension and other components of metabolic syndrome usually derive from trials' secondary end points. Taking this limitation in mind, bariatric/metabolic surgery action on blood pressure is reaching a significant proportion of hypertension resolution or improvement. In this review, we discussed the current evidence on the impact of bariatric/metabolic surgery on blood pressure control and pointed out perspectives in this research area.

Roles of the gut in the metabolic syndrome: an overview

The metabolic syndrome is a cluster of risk factors (central obesity, hyperglycaemia, dyslipidaemia and arterial hypertension), indicating an increased risk of diabetes, cardiovascular disease and premature mortality. The gastrointestinal tract is seldom discussed as an organ system of principal importance for metabolic diseases. The present overview connects various metabolic research lines into an integrative physiological context in which the gastrointestinal tract is included. Strong evidence for the involvement of the gut in the metabolic syndrome derives from the powerful effects of weight-reducing (bariatric) gastrointestinal surgery. In fact, gastrointestinal surgery is now recommended as a standard treatment option for type 2 diabetes in obesity. Several gut-related mechanisms that potentially contribute to the metabolic syndrome will be presented. Obesity can be caused by hampered release of satiety-signalling gut hormones, reduced meal-associated energy expenditure and microbiota-assisted harvest of energy from nondigestible food ingredients. Adiposity per se is a well-established risk factor for hyperglycaemia. In addition, a leaky gut mucosa can trigger systemic inflammation mediating peripheral insulin resistance that together with a blunted incretin response aggravates the hyperglycaemic state. The intestinal microbiota is strongly associated with obesity and the related metabolic disease states, although the mechanisms involved remain unclear. Enterorenal signalling has been suggested to be involved in the pathophysiology of hypertension and postprandial triglyceride-rich chylomicrons; in addition, intestinal cholesterol metabolism probably contributes to atherosclerosis. It is likely that in the future, the metabolic syndrome will be treated according to novel pharmacological principles interfering with gastrointestinal functionality.

What is the impact on the healthcare system if access to bariatric surgery is delayed?

BACKGROUND

Bariatric surgery has been available as part of the Brazilian Public Health System for patients with body mass index>40 kg/m² (or>35 kg/m² with co-morbidities) since 1999. However, access to surgery is challenging, with eligible patients waiting up to 7 years before surgery.

OBJECTIVE

Our objective was to compare costs and effectiveness of different waiting times before surgery versus prompt surgery.

SETTINGS

Public practice.

METHODS

A Markov microsimulation model compared 5 different strategies: no surgery, prompt surgery, and delaying surgery for 1, 2, 4, and 7 years. Markov tracker variables and states reflected changes in body mass index, type 2 diabetes status (including remission and relapse), and cardiovascular events. Time horizon was 20 years; discount rate, 5%; and the perspective of the Brazilian Public Health System. Effectiveness was calculated as quality adjusted life years.

RESULTS

Prompt surgery was the least costly and most effective strategy compared with any delay. Costs increased and effectiveness diminished progressively with the length of delays. Waiting 7 years for surgery was the most expensive and least effective strategy. Prompt surgery maintained dominance in 99.9%, 90.7%, 96.1%, and 94.2% of simulations in probabilistic sensitivity analyses versus 1-, 2-, 4-, and 7-year delays, respectively. Immediate surgery was very cost effective compared with no surgery in the case base. In the scenario with all patients having type 2 diabetes, immediate surgery was dominant to any strategy, including the no surgery group.

CONCLUSIONS

Delaying bariatric operations is more expensive and less effective compared with prompt surgery and very cost effective compared with no surgery. Public health systems should pursue strategies to accelerate access to surgery to decrease obesity related complications and mortality of patients, but also to improve cost effectiveness.

Practical Recommendations of the Obesity Management Task Force of the European Association for the Study of Obesity for the Post-Bariatric Surgery Medical Management

Bariatric surgery is today the most effective long-term therapy for the management of patients with severe obesity, and its use is recommended by the relevant guidelines of the management of obesity in adults. Bariatric surgery is in general safe and effective, but it can cause new clinical problems and is associated with specific diagnostic, preventive and therapeutic needs. For clinicians, the acquisition of special knowledge and skills is required in order to deliver appropriate and effective care to the post-bariatric patient. In the present recommendations, the basic notions needed to provide first-level adequate medical care to post-bariatric patients are summarised. Basic information about nutrition, management of co-morbidities, pregnancy, psychological issues as well as weight regain prevention and management is derived from current evidences and existing guidelines. A short list of clinical practical recommendations is included for each item. It remains clear that referral to a bariatric multidisciplinary centre, preferably the one performing the original procedure, should be considered in case of more complex clinical situations.

Quality criteria in bariatric surgery: Consensus review and recommendations of the Spanish Association of Surgeons and the Spanish Society of Bariatric Surgery

Bariatric surgery has proven to be highly effective in controlling obesity and metabolic syndrome; the results of this surgery are not only expressed in terms of weight loss, but also in terms of resolution of comorbidities, improved quality of life and complications. The different parameters used to measure these outcomes require uniformity and reference patterns. Therefore, it is essential to identify those indicators and quality criteria that are helpful in defining the «best practice» principles in bariatric surgery. In this regard, the Section of Obesity of the Spanish Association of Surgeons, in collaboration with the Spanish Society for Bariatric Surgery (SECO), present as an objective to identify the key points that define «quality» in this type of surgery. We describe the main indicators based on the published literature as well as the criteria for referral of the main comorbidities according to the evidence found and grades of recommendation.

Early 24-hour blood pressure response to Roux-en-Y gastric bypass in obese patients

Recently, it has been proposed, that the blood pressure (BP) lowering effect of gastric bypass surgery not only is explained by the obtained weight loss, but that the anatomical rearrangement of the gut after 'malabsorptive' surgical techniques, such as the laparoscopic Roux-en-Y gastric bypass (LRYGB), may affect BP through a change in a putative 'entero-renal' axis. If so one could anticipate a reduction in BP even before a noticeable weight loss was obtained. The purpose of the present study was to investigate the very early BP response to LRYGB surgery. Ten severely obese hypertensive (mean BMI 40.8 kg/m²) and 10 severely obese normotensive (mean BMI 41.7 kg/m²) patients underwent 24-h ambulatory blood pressure measurements (24 h ABPMs) before LRYGB and again day 1 and day 10 after LRYGB. No change in 24 h BP was observed day 1 after LRYGB. Day 10 after surgery both hypertensive and normotensive patients demonstrated a significant 12.6 mmHg and 9.5 reduction in systolic BP (SBP), respectively. Mean arterial pressure (MAP) decreased by 8.3 and 5.4 mmHg. At day 10 postoperatively, a weight loss of 7.9 kg in the hypertensive patients and 7.0 kg in the normotensive patients was observed. The reduction in BP after LRYGB takes place before any substantial weight loss has occurred. The reason for this remains speculative, but obese hypertensive patients may clearly benefit from the operation even if the goal of achieving 'normoweight' is not obtained.

Oral drug therapy following bariatric surgery: an overview of fundamentals, literature and clinical recommendations

Bariatric surgery is the most effective solution for severe obesity and obesity with comorbidities, and the number of patients going through bariatric surgery is rapidly and constantly growing. The modified gastrointestinal anatomy of the patient may lead to significant pharmacokinetic alterations in the oral absorption of drugs after the surgery; however, because of insufficient available literature and inadequate awareness of the medical team, bariatric surgery patients may be discharged from the hospital with insufficient instructions regarding their medication therapy. In this article, we aim to present the various mechanisms by which bariatric surgery may influence oral drug absorption, to provide an overview of the currently available literature on the subject, and to draw guidelines for the recommendations bariatric surgery patients should be instructed before leaving the hospital. To date, and until more robust data are published, it is essential to follow and monitor patients closely for safety and efficacy of their medication therapies, both in the immediate and distant time post-surgery.

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.