4 BMI (kg/m2 ) Applications per day Once daily Twice daily P Procedure SG RYGBP GB Number of patients (n) 3026 4901 2730 6 3 1 2009 48.4 51.0 <0.001 Thrombosis Total 48.4 51.5 <0.001 2010 48.4 51.6 <0.001 0.20 (0.07–0.43) 0.06 (0.01–0.18) 0.04 (0.00–0.20) Table 4: Correlation between BMI and VTE prophylaxis. 2005 48.5 50.0 0.179 2006 48.3 55.0 <0.001 2007 48.1 51.5 <0.001 Year 2008 48.4 51.6 <0.001 3 3 2 0.10 (0.02–0.29) 0.06 (0.01–0.18) 0.07 (0.01–0.26) Table 5: Diagnosed events of VTE and PE during the ﬁrst 90 postoperative days in dependence on operative procedure. Number of VTE (n) VTE risk (95% conﬁdence interval) (%) Number of patients (n) PE risk (95% conﬁdence interval) (%) 3.7%. The gender-speciﬁc aspect of VTE and PE was not detected in German Nationwide Survey. Data of Winegar et al. show a higher risk for male patient (HR 2.32, 95% CI 1.81–2.98) [15].The problem of BOLD Registry is missing informations on medication, dose of medication, and peri- and postoperative treatment. Scholten et al. have shown the positive eﬀect of a certain dosage of Enoxaparin on the risk for PE. Higher doses resulted in a signiﬁcantly lower rate of PE. A higher incidence of bleeding was not estimated [19]. Data contrary to the association of dosage and BMI have been obtained in a randomized study by Kalfarentzos et al., who did not observe any diﬀerence in the frequency of thromboembolic episodes under various dosages of Fraxiparin [20]. Data of German Nationwide Survey did not evaluate a higher incidence of bleeding when using a higher dosage of LWMH. At the most participating centers, a higher dosage is used only in high BMI patients without using exactly weight-adjusted LMWH. Further studies favor the administration of unfractionated- heparin depending on the monitoring of factors Xa in high- risk patients [21–23]. However, the associations between the anti-Factor-Xa level, dosage of LWMH, and occurrence of bleeding have been excluded in a previous study [24]. Evidence-based data on the optimal duration; type and dosage of LWMH for prophylaxis of VTE and PE do not exist in the literature. Cohort analysis of 17, 434 patients after bariatric opera- tions describe an outpatient department VTE incidence of 0.88%. More than 74% of thromboembolic complications occur after patients discharge and one-third after 1 month postoperatively. Highest incidence of VTE and PE was observed after RYGBP (OR = 0.31). Evaluated risk factors are male gender (OR = 1.68), age above 55 years (OR = 2.18), nicotine abuse (OR = 1.86), and medical history of VTE (OR = 7.48) [25]. Data of “PROBE-Study” had evaluated as risk factors for the development of a PE after bariatric surgery, smoking, age >40 years, >60 kg/m2, and previous history of venous thromboembolism [11]. For high-risk patients with a >50 kg/m2, a medical his- tory of VTE, surgical interventions at the pelvis, and heart failure in further studies, the positive eﬀect of an IVC ﬁlter was found [26–29]. Actual data on PE and VTE in bariatric surgery show similar to evaluated data of German Nationwide Survey on bariatric surgery a low incidence of 0.49% (n = 29, 323) [9, 15, 30]. The current ASMBS statement recommends performing compression therapy and medication for the prophylaxis of thromboembolism. The AWMF guidelines classify patients with a >30 kg/m2 as high risk, but there is a lack of appropriate recommendations for the prophylaxis of thromboembolism in bariatric surgery [6, 9]. 5. Conclusions and Recommendations Present published review on thromboembolism after laparo- scopic bariatric surgery has shown that available evidence on use of antithrombotic prophylaxis is limited [9]. Based on a literature search, the following predictive fac- tors were evaluated for the occurrence of thromboembolism after bariatric interventions: (1) age above 50 years, (2) smoking, (4) venous stasis [16], (5) BMI > 50 kg/m2, (6) visceral obesity, (3) thrombosis/pulmonary embolism in medical history [31, 32], (7) pulmonary hypoventilation [13], (8) ventricle septum defect (VSD) and aortic stenosis [33]. The dosage of NMH should be adapted for risk patients with (i) BMI > 50 kg/m2 [34], (ii) age above 50 years, (iii) male gender,