Portomesenteric Venous Thrombosis after Bariatric Surgery: A Case Series and Systematic Review Comparing LSG and LRYGB.

(1) Background: Portomesenteric Venous Thrombosis (PMVT) is a rare but serious complication of Metabolic Bariatric Surgery (MBS). Although more frequently reported after laparoscopic sleeve gastrectomy (LSG), the risk factors for PMVT remain unclear. This study aims to compare the incidence and determinants of PMVT between LSG and laparoscopic Roux-en-Y gastric bypass (LRYGB). (2) Methods: A retrospective analysis of 5235 MBSs conducted at our institution between 2015 and 2023 identified five cases of PMVT. Additionally, a systematic review in March 2023, covering PubMed, Web of Science and Scopus, was performed. Several data were analyzed regarding risk factors. (3) Results: In our case series, the incidence of PMVT was 0.1%. The five cases described involved four females with a BMI between 39.7 and 56.0 kg/m 2 . Their comorbidities were associated with metabolic syndrome, all women used oral contraceptive and two patients were diagnosed with thrombophilia or pulmonary embolism. Per protocol, thromboprophylaxis was administered to all patients. Diagnosis was made at a median of 16 days post-surgery, with abdominal pain being the main presenting symptom. Acute cases were managed with enoxaparin, unfractionated heparin and fibrinolysis. One patient required surgery. Ten studies were included in the systematic review and 205 patients with PMVT were identified: 193 (94.1%) post-LSG and 12 post-LRYGB. The most common comorbidities were dyslipidemia, hypertension, diabetes, sleep apnea and liver disorders; (4) Conclusions: PMVT is a potentially life-threatening complication after MBS, requiring preventive measures, timely diagnosis and several treatments. Our findings suggest a higher occurrence in women with an elevated BMI and post-LSG. Tailored thromboprophylaxis for MBS patients at risk of PMVT may be warranted.