Haemostatic and fibrinolytic changes in obese subjects undergoing bariatric surgery: the effect of different surgical procedures.

Background Little is known about effects of different bariatric surgery procedures on haemostatic and fibrinolytic parameters. Material and methods Consecutive obese subjects undergoing gastric bypass (GBP) or sleeve gastrectomy (SG) were enrolled. In all patients, levels of haemostatic factors (FII, FVII, FVIII, FIX, FX, vWF, fibrinogen), fibrinolytic variables (PAI-1, t-PA and D-dimer) and natural anticoagulants (AT, protein C and protein S) were evaluated before and 2 months after surgery. Results A total of 77 GBP and 79 SG subjects completed the study. At baseline no difference in coagulation parameters was found between the two groups. After both GBP and SG, subjects showed significant changes in haemostatic and fibrinolytic variables and in natural anticoagulant levels. The Δ% changes in FVII, FVIII, FIX, vWF, fibrinogen, D-dimer, protein C and protein S levels were significantly higher in subjects who underwent GBP than in those who underwent SG. Multivariate analysis confirmed that GBP was a predictor of higher Δ% changes in FVII (β=0.268, p=0.010), protein C (β=0.274, p=0.003) and protein S (β=0.297, p<0.001), but not in all the other variables. Following coagulation factor reduction, 31 subjects (25.9% of GBP and 13.9% of SG; p=0.044) showed overt FVII deficiency; protein C deficiency was reported by 34 subjects (32.5% of GBP vs 11.4% of SG, p=0.033) and protein S deficiency by 39 (37.6% of GBP vs 12.6% of SG, p=0.009). Multivariate analyses showed that GBP was associated with an increased risk of deficiency of FVII (OR: 3.64; 95% CI: 1.73–7.64, p=0.001), protein C (OR: 4.319; 95% CI: 1.33–13.9, p=0.015) and protein S (OR: 5.50; 95% CI: 1.71–17.7, p=0.004). Discussion GBP is associated with an increased risk of post-operative deficiency in some vitamin K-dependent coagulation factors. Whereas such deficiency is too weak to cause bleeding, it is significant enough to increase the risk of thrombosis.