Early benefits of bariatric surgery on subclinical cardiac function: Contribution of visceral fat mobilization

The effect of bariatric surgery type on cardiac reverse remodelling

INTRODUCTION

Bariatric surgery is effective in reversing adverse cardiac remodelling in obesity. However, it is unclear whether the three commonly performed operations; Roux-en-Y Gastric Bypass (RYGB), Laparoscopic Sleeve Gastrectomy (LSG) and Laparoscopic Adjustable Gastric Band (LAGB) are equal in their ability to reverse remodelling.

METHODS

Fifty-eight patients underwent CMR to assess left ventricular mass (LVM), LV mass:volume ratio (LVMVR) and LV eccentricity index (LVei) before and after bariatric surgery (26 RYGB, 22 LSG and 10 LAGB), including 46 with short-term (median 251-273 days) and 43 with longer-term (median 983-1027 days) follow-up. Abdominal visceral adipose tissue (VAT) and epicardial adipose tissue (EAT) were also assessed.

RESULTS

All three procedures resulted in significant decreases in excess body weight (48-70%). Percentage change in VAT and EAT was significantly greater following RYGB and LSG compared to LAGB at both timepoints (VAT:RYGB -47% and -57%, LSG -47% and -54%, LAGB -31% and -25%; EAT:RYGB -13% and -14%, LSG -16% and -19%, LAGB -5% and -5%). Patients undergoing LAGB, whilst having reduced LVM (-1% and -4%), had a smaller decrease at both short (RYGB: -8%, p < 0.005; LSG: -11%, p < 0.0001) and long (RYGB: -12%, p = 0.009; LSG: -13%, p < 0.0001) term timepoints. There was a significant decrease in LVMVR at the long-term timepoint following both RYGB (-7%, p = 0.006) and LSG (-7%, p = 0.021), but not LAGB (-2%, p = 0.912). LVei appeared to decrease at the long-term timepoint in those undergoing RYGB (-3%, p = 0.063) and LSG (-4%, p = 0.015), but not in those undergoing LAGB (1%, p = 0.857). In all patients, the change in LVM correlated with change in VAT (r = 0.338, p = 0.0134), while the change in LVei correlated with change in EAT (r = 0.437, p = 0.001).

CONCLUSIONS

RYGB and LSG appear to result in greater decreases in visceral adiposity, and greater reverse LV remodelling with larger reductions in LVM, concentric remodelling and pericardial restraint than LAGB.

Bariatric surgery, through beneficial effects on underlying mechanisms, improves cardiorenal and liver metabolic risk over an average of ten years of observation: A longitudinal and a case-control study

BACKGROUND

Bariatric surgery has long-term beneficial effects on body weight and metabolic status, but there is an apparent lack of comprehensive cardiometabolic, renal, liver, and metabolomic/lipidomic panels, whereas the underlying mechanisms driving the observed postoperative ameliorations are still poorly investigated. We aimed to study the long-term effects of bariatric surgery on metabolic profile, cardiorenal and liver outcomes in association with underlying postoperative gut hormone adaptations.

METHODS

28 individuals who underwent bariatric surgery [17 sleeve gastrectomy (SG), 11 Roux-en-Y gastric bypass (RYGB)] were followed up 3, 6 and 12 and at 10 years following surgery. Participants at 10 years were cross-sectionally compared with an age-, sex- and adiposity-matched group of non-operated individuals (n = 9) and an age-matched pilot group of normal-weight individuals (n = 4).

RESULTS

There were durable effects of surgery on body weight and composition, with an increase of lean mass percentage persisting despite some weight regain 10 years postoperatively. The improvements in metabolic and lipoprotein profiles, cardiometabolic risk markers, echocardiographic and cardiorenal outcomes persisted over the ten-year observation period. The robust improvements in insulin resistance, adipokines, activin/follistatin components and postprandial gastrointestinal peptide levels persisted 10 years postoperatively. These effects were largely independent of surgery type, except for a lasting reduction of ghrelin in the SG subgroup, and more pronounced increases in proglucagon products, mainly glicentin and oxyntomodulin, and in the cardiovascular risk marker Trimethylamine-N-oxide (TMAO) within the RYGB subgroup. Despite similar demographic and clinical features, participants 10 years after surgery showed a more favorable metabolic profile compared with the control group, in conjunction with a dramatic increase of postprandial proglucagon product secretion.

CONCLUSIONS

We demonstrate that cardiorenal and metabolic benefits of bariatric surgery remain robust and largely unchanged ten years postoperatively and are associated with durable effects on gastrointestinal- muscle- and adipose tissue-secreted hormones.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04170010.

Body Fat Distribution, Diabetes Mellitus, and Cardiovascular Disease: an Update

PURPOSE OF REVIEW

Specific measures of body fat distribution may have particular value in the development and treatment of cardiometabolic conditions, such as cardiovascular disease (CVD) and diabetes mellitus (DM). Here, we review the pathophysiology, epidemiology, and recent advances in the identification and management of body fat distribution as it relates to DM and CVD risk.

RECENT FINDINGS

Accumulation of visceral and ectopic fat is a major contributor to CVD and DM risk above and beyond the body mass index (BMI), yet implementation of fat distribution assessment into clinical practice remains a challenge. Newer imaging-based methods offer improved sensitivity and specificity for measuring specific fat depots. Lifestyle, pharmacological, and surgical interventions allow a multidisciplinary approach to reduce visceral and ectopic fat. A focus on implementation of body fat distribution measurements into clinical practice should be a priority over the next 5 to 10 years, and clinical assessment of fat distribution can be considered to refine risk evaluation and to develop improved and effective preventive and therapeutic strategies for high-risk obesity.

Milestones in the journey towards addressing obesity; Past trials and triumphs, recent breakthroughs, and an exciting future in the era of emerging effective medical therapies and integration of effective medical therapies with metabolic surgery

The 21st century is characterized by an increasing incidence and prevalence of obesity and the burden of its associated comorbidities, especially cardiometabolic diseases, which are reaching pandemic proportions. In the late '90s, the "black box" of adipose tissue and energy homeostasis was opened with the discovery of leptin, transforming the adipose tissue from an "inert fat-storage organ" to the largest human endocrine organ and creating the basis on which more intensified research efforts to elucidate the pathogenesis of obesity and develop novel treatments were based upon. Even though leptin was eventually not proven to be the "standalone magic bullet" for the treatment of common/polygenic obesity, it has been successful in the treatment of monogenic obesity syndromes. Additionally, it shifted the paradigm of treating obesity from a condition due to "lack of willpower" to a disease due to distinct underlying biological mechanisms for which specific pharmacotherapies would be needed in addition to lifestyle modification. Subsequently, the melanocortin pathway proved to be an equally valuable pathway for the pharmacotherapy of obesity. Melanocortin receptor agonists have recently been approved for treating certain types of syndromic obesity. Other molecules- such as incretins, implicated in energy and glucose homeostasis- are secreted by the gastrointestinal tract. Glucagon-like peptide 1 (GLP-1) is the most prominent one, with GLP-1 analogs approved for common/polygenic obesity. Unimolecular combinations with other incretins, e.g., GLP-1 with gastric inhibitory polypeptide and/or glucagon, are expected to be approved soon as more effective pharmacotherapies for obesity and its comorbidities. Unimolecular combinations with other compounds and small molecules activating the receptors of these molecules are currently under investigation as promising future pharmacotherapies. Moreover, metabolic and bariatric surgery has also demonstrated impressive results, especially in the case of morbid obesity. Consequently, this broadening therapeutic armamentarium calls for a well-thought-after and well-coordinated multidisciplinary approach, for instance, through cardiometabolic expertise centers, that would ideally address effectively and cost-effectively obesity and its comorbidities, providing tangible benefits to large segments of the population.

Reducing Cardiac Steatosis: Interventions to Improve Diastolic Function - A Narrative Review

Heart failure is one of the main causes of morbidity and mortality around the globe. Heart failure with preserved ejection fraction is primarily caused by diastolic dysfunction. Adipose tissue deposition in the heart has been previously explained in the pathogenesis of diastolic dysfunction. In this article, we aim to discuss the potential interventions that can reduce the risk of diastolic dysfunction by reducing cardiac adipose tissue. A healthy diet with reduced dietary fat content can reduce visceral adiposity and improve diastolic function. Aerobic and resistance exercises also reduce visceral and epicardial fat and ameliorate diastolic dysfunction. Some medications, include metformin, glucagon-like peptide-1 analogues, dipeptidyl peptidase-4 inhibitors, thiazolidinediones, sodium-glucose co-transporter-2, inhibitors, statins, ACE-Is, and ARBs, have shown different degrees of effectiveness in improving cardiac steatosis and diastolic function. Bariatric surgery has also shown promising results in this field.

The Early Effects of Bariatric Surgery on Cardiac Structure and Function: a Systematic Review and Meta-Analysis

BACKGROUND

This meta-analysis was performed to investigate how cardiac structures and functions change in the very early stage after bariatric surgery.

MATERIALS AND METHODS

We thoroughly searched the PubMed, Embase, Cochrane Library, and Web of Science databases for articles including patients who underwent bariatric surgery and examined the changes of their cardiac indices. Results were pooled by using Review Manager 5.1 and Stata 12.0. Weighted mean differences (WMDs) with 95% confidence intervals (CIs) were obtained. The I-squared (I²) test was used to determine the heterogeneity between studies. To identify publication bias, funnel plots and Egger's test were utilized. The leave-one-out method was used to conduct sensitivity analysis.

RESULTS

In this meta-analysis, 24 research including 942 patients were considered. According to our findings, most cardiac indices changed 3-6 months following bariatric surgery. An improvement in cardiac geometry was reflected by a reduction in left ventricular mass (LVM) (WMD =  - 22.06, 95% CI = (- 27.97, - 16.16)). The left ventricular diastolic function improved, as reflected by the decrease in the E/e' ratio (WMD =  - 0.90, 95% CI = (- 1.83, - 0.16)). Left ventricular ejection fraction (LVEF) did not show an obvious change (WMD = 0.94, 95% CI = (- 0.19, 2.07)), while a more sensitive indicator of left ventricular systolic function, left ventricular longitudinal strain (LV LS), increased (WMD =  - 2.43, 95% CI = (- 3.96, - 0.89)).

CONCLUSION

This meta-analysis includes the newest and most comprehensive cardiac indices to prove that cardiac structures and functions are improved early after bariatric surgery, which has not been reported by any other studies.

Changes in abdominal fat depots after bariatric surgery are associated with improved metabolic profile

BACKGROUND AND AIMS

Obesity associated with a change in the quantity and quality of fat depots. Using computed tomography (CT), we analyzed abdominal fat depots in patients with obesity after bariatric surgery according to their metabolic health status.

METHODS AND RESULTS

We recruited 79 individuals with metabolically unhealthy obesity before bariatric surgery and compared them with age-sex matched healthy controls. The volume and fat attenuation index (FAI) of fat depots were measured using CT scans that were conducted prior to and a year after bariatric surgery. 'Metabolically healthy' was defined as having no hypertension, normal fasting glucose and a waist-to-hip ratio of <1.05 for men and <0.95 for women. Individuals who achieved a metabolic health status conversion (MHC) (n = 29, 37%)-from unhealthy to healthy-were younger (p < 0.001) as compared to individuals without MHC. Pre-surgery BMI and reduction of BMI did not differ between the two groups (p = 0.099, p = 0.5730). Bariatric surgery reduced the volume and increased the FAI of fat depots. Baseline lower abdominal periaortic adipose tissue (AT) volume (p = 0.014) and great percent reduction in renal sinus AT volume after surgery (p = 0.019) were associated with MHC after surgery. Increased intraperitoneal AT FAI (p = 0.031) was also associated with MHC.

CONCLUSION

MHC was not associated with improvement in general obesity, based on indicators such as reduction of BMI after surgery. Weight reduction induced specific abdominal fat depot changes measured by CT are positively associated with MHC.

The Impact of Bariatric Surgery on Cardiac Structure, and Systolic and Diastolic Function in Patients with Obesity: A Systematic Review and Meta-analysis

The purpose of this study was to provide pooled data from all studies on the impact of bariatric surgery on cardiac structure, and systolic and diastolic function evaluated by either echocardiography or cardiac magnetic resonance. PubMed, Web of Science, Embase, and Scopus databases were searched. Almost all of cardiac left-side structural indices improved significantly after bariatric surgery. However, right-side structural indices did not change significantly. Left ventricular ejection fraction and most of the diastolic function indices improved significantly after the bariatric surgery. The subgroup analysis showed that the left ventricular mass index decreased more in long-term follow-up (≥ 12 months). In addition, subgroup analysis of studies based on surgery type did not reveal any difference in outcomes between gastric bypass and sleeve gastrectomy groups.

Bariatric Surgery and Myocardial Mechanics: A Meta-Analysis of Speckle Tracking Echocardiographic Studies

Aim: Current evidence on the effects of bariatric surgery on cardiac mechanics in patients with obesity is based on a few single studies. We investigated this issue through a meta-analysis of speckle tracking echocardiography (STE) studies that reported data on changes in left ventricular (LV) mechanics as assessed by global longitudinal strain (GLS). Methods: The PubMed, OVID-MEDLINE and Cochrane library databases were systematically analysed to search English-language articles published from inception to 31 May 2022. Studies were identified by using Me-SH terms and crossing the following terms: “obesity”, “bariatric surgery”, “left ventricular mechanics”, “left ventricular hypertrophy”, “systolic dysfunction”, “global longitudinal strain”, “echocardiography” and “STE echocardiography”. Results: The meta-analysis, including a total of 512 patients with obesity from 13 studies (follow-up 1−23 months), showed a significant GLS improvement after bariatric procedures, with standard mean difference (SMD) being 0.50 ± 0.08, CI: 0.34/0.65, p < 0.0001. Corresponding SMD value for LV ejection fraction (LVEF) was 0.15 ± 0.09, CI: −0.04/0.34, p = 0.11. A sensitivity analysis restricted to 11 studies with follow-up ≥ 6 months confirmed that GLS (SMD: 0.47 ± 0.08, CI: 0.30/0.63, p < 0.0001) but not LVEF (SMD: 0.14 ± 0.11, CI: −0.08/0.37, p = 0.21) improved after surgery. Conclusions: Our meta-analysis adds a new piece of information on the beneficial effects of bariatric surgery on LV systolic function and, more importantly, suggests that the assessment of myocardial strain should be routinely implemented for a comprehensive evaluation of cardiac functional changes associated with bariatric procedures.

Association of Bariatric Surgery With Vascular Outcomes

IMPORTANCE

Bariatric surgical weight loss is associated with reduced cardiovascular mortality; however, the mechanisms underlying this association are incompletely understood.

OBJECTIVES

To identify variables associated with vascular remodeling after bariatric surgery and to examine how sex, race, and metabolic status are associated with microvascular and macrovascular outcomes.

DESIGN, SETTING, AND PARTICIPANTS

This population-based longitudinal cohort included 307 individuals who underwent bariatric surgery. Participants were enrolled in the bariatric weight loss program at Boston Medical Center, a large, multi-ethnic urban hospital, with presurgical and postsurgical assessments. Data were collected from December 11, 2001 to August 27, 2019. Data were analyzed in September 2019.

EXPOSURE

Bariatric surgery.

MAIN OUTCOMES AND MEASURES

Flow-mediated dilation (FMD) and reactive hyperemia (RH) (as measures of macrovascular and microvascular function, respectively) and clinical variables were measured preoperatively at baseline and at least once postoperatively within 12 months of the bariatric intervention.

RESULTS

A total of 307 participants with obesity (mean [SD] age, 42 [12] years; 246 [80%] women; 199 [65%] White; mean [SD] body mass index, 46 [8]) were enrolled in this study. Bariatric surgery was associated with significant weight loss and improved macrovascular and microvascular function across subgroups of sex, race, and traditional metabolic syndrome (mean [SD] pre- vs postsurgery weight: 126 [25] kg vs 104 [25] kg; P < .001; mean [SD] pre- vs postsurgery FMD: 9.1% [5.3] vs 10.2% [5.1]; P < .001; mean [SD] pre- vs postsurgery RH: 764% [400] vs 923% [412]; P < .001). Factors associated with change in vascular phenotype correlated most strongly with adiposity markers and several metabolic variables depending on vascular territory (eg, association of weight change with change in RH: estimate, -3.2; 95% CI, -4.7 to -1.8; association of hemoglobin A1c with change in FMD: estimate, -0.5; 95% CI, -0.95 to -0.05). While changes in macrovascular function among individuals with metabolically healthy obesity were not observed, the addition of biomarker assessment using high-sensitivity C-reactive protein plasma levels greater than 2 mg/dL identified participants with seemingly metabolically healthy obesity who had low-grade inflammation and achieved microvascular benefit from weight loss surgery.

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that bariatric intervention is associated with weight loss and favorable remodeling of the vasculature among a wide range of individuals with cardiovascular risk. Moreover, differences in arterial responses to weight loss surgery by metabolic status were identified, underscoring heterogeneity in physiological responses to adiposity change and potential activation of distinct pathological pathways in clinical subgroups. As such, individuals with metabolically healthy obesity represent a mixed population that may benefit from more refined phenotypic classification.