207 Portomesenteric Venous Thrombosis Post-Metabolic Bariatric Surgery: A Meta-Analysis and a UK Regional Bariatric Centre Experience

Abstract Aim To assess the incidence of portomesenteric venous thrombosis (PMVT) in a UK regional bariatric centre and conduct a systematic review and meta-analysis comparing PMVT rates in laparoscopic sleeve gastrectomy (LSG) and Roux-en-Y gastric bypass (RYGB). Method A five-year retrospective review (2020–2024) of metabolic bariatric surgery (MBS) cases at a regional UK centre analysed demographics, procedures, PMVT incidence, risk factors, and thromboprophylaxis use. A systematic review and meta-analysis followed PRISMA guidelines comparing PMVT incidence in LSG and RYGB. Statistical analysis was performed using SPSS v22, with meta-analysis in RevMan 5.4. Results The meta-analysis included 14 studies with 105,329 cases (69,767 LSG, 35,562 RYGB). PMVT incidence was 0.24%, significantly higher in LSG (OR 7.13 [3.93,12.92], p<0.0001). Most PMVT occurred within 30 days (OR 21.21 [11.74,38.32], p<0.00001). Risk factors included female gender, contraceptive use, and metabolic syndromes; 13% of PMVT patients had no extended thromboprophylaxis. Mortality was 3.7%. No published UK data on PMVT after LSG or RYGB. In our cohort of 342 patients (LSG 34.8%, RYGB 34.2%, mini gastric bypass [MGB] 31%), routine extended thromboprophylaxis was administered for 2 weeks. No PMVT or VTE events were observed during the follow-up, despite the meta-analysis indicates that most PMVT cases occur within 30 days postoperatively. Conclusions No PMVT cases were reported in our cohort, aligning with the wider UK experience. This raises key questions about surgical technique, thromboprophylaxis protocols, patient selection, or genetic factors underlying the lower UK rates. Further multicentre research is needed to clarify mechanisms and optimise preventive strategies, particularly for LSG patients.