Metabolic bariatric surgery (MBS) induces substantial metabolic, inflammatory, and nutritional changes that can alter hemostatic balance through redox-dependent mechanisms. This systematic review evaluated coagulation disturbances after MBS with emphasis on oxidative stress and micronutrient deficiencies. A structured search of PubMed, Scopus, and Web of Science (2000-2025) identified 1707 records; 21 studies met inclusion criteria. Available evidence suggests that although MBS reduces obesity-related inflammation and oxidative burden in many patients, a proportion of individuals may present with persistent redox imbalance, elevated D-dimer or vWF (von Willebrand Factor), and delayed normalization of fibrinolysis. Micronutrient deficiencies-particularly vitamins K, B12, folate, selenium, zinc, and copper-are common after malabsorptive procedures and contribute to both thrombotic and hemorrhagic complications by impairing antioxidant defenses, endothelial function, and vitamin K-dependent coagulation pathways. Postoperative venous thromboembolism (VTE) incidence ranges from 0.3 to 0.5%, with higher risk after Roux-en-Y gastric bypass than sleeve gastrectomy, while bleeding is primarily associated with vitamin K deficiency, marginal ulcers, and anticoagulant exposure. The findings underscore the interdependence of oxidative stress, nutritional status, and hemostasis after MBS. Individualized thromboprophylaxis, routine detection of micronutrient deficiencies, and long-term biochemical monitoring are essential to maintain hemostatic stability. Standardized redox-hemostasis biomarker panels are needed to clarify mechanistic pathways and improve postoperative preventive strategies.
Keywords: bariatric surgery; bleeding complications; coagulation disorders; oxidative stress; redox imbalance; venous thromboembolism; vitamin K.