Byrne, James Patrick

Abstract Background: With over 1 billion individuals affected globally, obesity and obesity related diseases is now a leading cause of death. Metabolic and bariatric surgery (MBS) has emerged as a cornerstone intervention for severe obesity and its associated comorbidities. Despite its efficacy, postoperative care and follow-up after MBS remains highly variable worldwide. Objective: The PARTNER study aimed to evaluate global clinical practices in the postoperative management following MBS by surveying multidisciplinary healthcare professionals . Methods: This study was an international online survey conducted between October 2024 and January 2025. A multidisciplinary team developed the questionnaire based on existing literature and international guidelines. The survey assessed five domains: follow-up care, postoperative treatment, dietary management, patient support, and measurement of surgical outcomes. Responses were analysed descriptively. Results: A total of 262 responses were received from 62 countries. Most respondents were bariatric surgeons (72.1%) working in public healthcare systems (73.3%). While 78.7% reported conducting three-month postoperative reviews, only 23.7% offered indefinite follow-up. Hybrid models of care (virtual and in-person) were common (56.9%). VTE prophylaxis and postoperative PPI use were recommended by 64.1% and 84.3% respectively. Nearly all respondents (98.1%) provided dietary advice, with protein and micronutrient supplementation widely endorsed. Only 56.1% routinely referred patients for psychological follow-up. Definitions of surgical success and failure varied widely, with inconsistent objective outcome measures. Conclusion: The PARTNER study reveals significant international variation in postoperative management practices following MBS. These findings underscore the need for more standardized, evidence-based guidelines to improve long-term outcomes and equity of care worldwide.

SummaryGlobal obesity rates have risen dramatically, now exceeding deaths from starvation. Metabolic and bariatric surgery (MBS), initially for severe obesity (BMI ≥35 kg/m2), is performed globally over 500 000 times annually, offering significant metabolic benefits beyond weight loss. However, varying eligibility criteria globally impact patient care and healthcare resources. Updated in 2022, ASMBS and IFSO guidelines aim to standardise MBS indications, reflecting current understanding and emphasising comprehensive preoperative assessments. Yet, clinical variability persists, necessitating consensus‐based recommendations. This modified Delphi study engaged 45 global experts to establish consensus on perioperative management in MBS. Experts selected from bariatric societies possessed expertise in MBS and participated in a two‐round Delphi protocol. Consensus was achieved on 90 of 169 statements (53.3%), encompassing multidisciplinary team composition, patient selection criteria, preoperative testing, and referral pathways. The agreement highlighted the critical role of comprehensive preoperative assessments and the integration of healthcare professionals in MBS. These findings offer essential insights to standardise perioperative practices and advocate for evidence‐based guidelines in MBS globally. The study underscores the need for unified protocols to optimise outcomes and guide future research in MBS.

Abstract Introduction Cardiac geometry is affected by body composition, with total body adipose volume being related to left ventricular (LV) dilatation (due to increased intravascular volume and cardiac output), and visceral adipose tissue (VAT) to smaller LV cavity size and concentric remodelling (because of insulin resistance) [1]. As such we hypothesised that changes in VAT and total body weight during weight loss would have a differential impact on cardiac geometry. Alongside this, we hypothesised that, as the pericardium is a fixed volume, changes in epicardial adipose tissue (EAT), may have an additional mechanical effect by reducing pericardial restraint. Purpose We sought to investigate long term changes in VAT, total weight and EAT following bariatric surgery and relate them to changes in cardiac geometry. Methods Forty patients underwent cardiac magnetic resonance (CMR) imaging before and after bariatric surgery, including 21 who underwent short-term (median 209 days), 28 medium-term (median 428 days) and 12 long-term (median 1030 days) imaging follow up. Cardiac volumes (left atrial (LA), LV end-diastolic volume (LVEDV) and stroke volume (LVSV)) were assessed using cardiac MRI. VAT was assessed at L5 using a T1 weighted, water suppressed sequence. EAT volumes were calculated by manual contouring in end-ventricular systole on short axis slices from the mitral valve to the apex. Percentage changes in volumes were calculated between scans for each individual. Results Patients on average lost 32kg within the first 428 days following bariatric surgery (54% excess weight loss, p<0.0001), with no significant change in weight at the longer-term time point (Figure 1A). Most VAT loss occurred in the first 209 days (−42%, p<0.0001) with no subsequent change observed at the final two timepoints (Figure 1B). Similarly, EAT loss occurred in the first 209 days (−13%, mean 10ml, p<0.0001) with non-significant changes thereafter (Figure 1C). There was a significant decrease in both LA (13%, mean 12ml, p<0.0001) and LVEDV (4%, mean 8ml, p=0.0249) at 209 days post-surgery. Both LA volume and LVEDV had returned to baseline by the longest term time point of 1030 days (Figure 2). LVSV followed a similar pattern being reduced at 209 days (by 10%, mean 9ml, p=0.0019), then returning to levels similar to those pre-weight loss at 1030 days (p=0.44) (Figure 2C). Conclusions Cardiac volumes show a biphasic response to weight loss, initially becoming smaller and then returning to baseline by 1030 days. We hypothesise that the early drop in LA and LV cavity size is a response to reduced volume from body mass reduction. In contrast, we propose that the increase in LA and LVEDV that follows results from the longer-term effects of reducing VAT, and increased space within the pericardium resulting from EAT loss allowing expansion to occur. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): We acknowledge support from the British Heart Foundation Oxford Center of Research Excellence

Abstract Aims We aimed to determine the effect of increasing body weight upon right ventricular (RV) volumes, energetics, systolic function, and stress responses using cardiovascular magnetic resonance (CMR). Methods and results We first determined the effects of World Health Organization class III obesity [body mass index (BMI) > 40 kg/m2, n = 54] vs. healthy weight (BMI < 25 kg/m2, n = 49) upon RV volumes, energetics and systolic function using CMR. In less severe obesity (BMI 35 ± 5 kg/m2, n = 18) and healthy weight controls (BMI 21 ± 1 kg/m2, n = 9), we next performed CMR before and during dobutamine to evaluate RV stress response. A subgroup undergoing bariatric surgery (n = 37) were rescanned at median 1 year to determine the effects of weight loss. When compared with healthy weight, class III obesity was associated with adverse RV remodelling (17% RV end-diastolic volume increase, P < 0.0001), impaired cardiac energetics (19% phosphocreatine to adenosine triphosphate ratio reduction, P < 0.001), and reduction in RV ejection fraction (by 3%, P = 0.01), which was related to impaired energetics (R = 0.3, P = 0.04). Participants with less severe obesity had impaired RV diastolic filling at rest and blunted RV systolic and diastolic responses to dobutamine compared with healthy weight. Surgical weight loss (34 ± 15 kg weight loss) was associated with improvement in RV end-diastolic volume (by 8%, P = 0.006) and systolic function (by 2%, P = 0.03). Conclusion Increasing body weight is associated with significant alterations in RV volumes, energetic, systolic function, and stress responses. Adverse RV modelling is mitigated with weight loss. Randomized trials are needed to determine whether intentional weight loss improves symptoms and outcomes in patients with obesity and heart failure.

Introduction: The mechanisms linking obesity to increased mortality in patients with coronavirus-disease 2019 (COVID-19) are unclear. Hypothesis: We hypothesised that obesity would be associated with adverse right ventricular (RV) remodelling and function which might be further exacerbated by COVID-19 associated increases in RV afterload/demand. Methods: We used echocardiography and computed tomography to establish links between RV dimensions and function and bodyweight in patients with severe COVID-19. In obese and non-obese participants without COVID-19, we used cardiovascular magnetic resonance to define the effects of obesity upon RV volumes, energetics, systolic function and stress reserve. Results: In patients with severe COVID-19, increasing bodyweight was associated with disproportionate RV dilatation (n=26, echocardiography, R=0.42, P=0.03, CT n=34, R=0.23, P=0.004) and impairment of RV systolic function (fractional area change (FAC) R=-0.45, P=0.04); obesity (BMI >30kg/m2) was associated with a 32% reduction in RV FAC (P=0.03). Similar associations were seen in a validation cohort (n=91, all P<0.05). In participants without COVID-19, class III obesity (n=54, BMI 47±4 kg/m 2 ) was associated with RV remodelling, impaired cardiac energetics (PCr/ATP ratio 23% lower, P<0.001) and reduction in RV systolic function at rest (by 3±1%, P=0.01), which was related to reduced energetics (R=0.3, P=0.04). Participants with class I-II obesity (BMI 35±5 kg/m 2 , n=27) had impaired RV diastolic filling rate at rest (P<0.001) and blunted RV dobutamine stress systolic response (by 68%, P=0.03) and diastolic response (by 78%, P=0.008). Surgical weight loss in patients obesity (n=37, 34±15kg weight loss) was associated with improvement in RV volume (12±26 ml lower, P=0.006) and function (ejection fraction 2±5% higher, P=0.03). Conclusions: Increasing body weight is associated with both significant alterations in RV volumes, systolic function and stress responses which are mitigated with weight loss and also with disproportionate RV dilatation and dysfunction in severe COVID-19. RV dysfunction is a modifiable mechanism which might link obesity to adverse outcomes in patients with COVID-19 and other disorders stressing the right heart.