Thrombosis Year BIB GB SG RYGBP BPD DS 54.2 100 100 100 100 Table 2: VTE prophylaxis in dependence on operation. 2005 (%) 2006 (%) 2007 (%) 2008 (%) 2009 (%) 2010 (%) Total (%) 59.5 99.2 100 100 100 23.6 96.9 97.7 99.3 100 100 21.9 98.5 99.2 99.8 100 100 Table 3: Duration on VTE prophylaxis in days. 28.6 97.7 96.1 97.0 100 100 2008 6 32.7 95.6 99.4 99.2 100 100 2009 6 36.7 97.9 98.8 99.2 100 100 3 2010 6 9.15 (1–105) Year 2005 Mean length of prophylaxis in days (d) 6.86 (1–47) Median of prophylaxis in days (d) 7 2006 7.62 (1–52) 7 2007 7.16 (1–86) 6 8.20 (1–210) 9.07 (1–110) 3.5. Risks for VTE and PE. VTE risk and risk of fatal PE could not evaluate any signiﬁcant diﬀerence in dependence on operative procedure for the most performed procedures GB, SG, and RYGBP (Table 5). Overall incidence of VTE was 0.06% (8/11835) and for PE 0.08% (10/11835). Comparing gender-speciﬁc risks for VTE we found no signiﬁcance diﬀerence between men and women. Risk for female patients is 0.06% and for male patients 0.09% (P = 0.5216). Increasing BMI correlates with a higher incidence on VTE until BMI of 49.9 kg/m2. In patients with BMI above 50 kg/m2 the VTE incidence dropped down (Table 6). Evaluated risk for VTE at the 90 ﬁrst postoperative days is for all procedures ≤0.10%. Incidence of PE for GB, SG, and RYGBP in German Nationwide Survey was ≤0.20% (Table 5). According gender- speciﬁc aspects exist no signiﬁcance diﬀerence for developing PE 90 days postoperatively (P = 0.5085). Risk factor for female patients was 0.08% (relative risk 0. 8773%) and for male patients 0.12% (relative risk 1.3242%) (Table 6). 4. Discussion German Nationwide Survey has evaluated the risk of VTE (0.06%) and PE (0.08%) in bariatric surgery Germany between 2005 and 2010. VTE or PE has been reported to the survey, when it was diagnosed by vascular ultrasound, CT scan, or echocardiography. According to the literature, the risk for the development of a PE after bariatric surgery is between 0.1% and 1.3% [11, 12]. The risk for thromboembolic complications in bariatric surgery in patients who did not receive in-hospital chemoprophylaxis is 2.4% [12, 13]. In particular, fatal PE (0.3%) needs to be considered as the strongest independent factor for perioperative mortality. DeMaria et al. have reported a mortality of 0.23% due to PE (10/4431 patients) [14]. Data of BOLD-Registry have shown a VTE risk 90 days postoperatively of 0.42% (n = 73, 971). 73% of VTE in this study have been developed after patients discharge during the ﬁrst 30 days [15]. However, no evidence-based data on optimal prophylaxis exist [9, 14]. According German AWMF-Guidelines and ACCP-Guidelines visceral surgery and morbid obesity is associated with the highest risk for VTE and PE [16]. Beneﬁt and risk of bleeding has to be considered if weight-adjusted LWMH is used for prophylaxis [9, 14, 15]. Using LWMH prophylaxis with pneumatic compression is widely used in bariatric surgery. Advantage of pneumatic compression in laparoscopic bariatric surgery is defending of venous stasis in lower extremity. German Nationwide Survey has a signiﬁcant reduction of antithrombotic prophylaxis for patients undergoing GB evaluated. This fact can be associated with the fact that GB is implanted during a short hospital stay of one or two days in several hospitals. For these patients we did not evaluate a higher incidence of VTE. As a bias of our study we cannot exclude that clinical symptoms of VTE or PE for these patients were not documented at the registry. In patients with BMI above 50 kg/m2 the incidence of VTE dropped down. In this fact as a bias of the study we cannot exclude that patients with BMI above 50 kg/m2 were treated with higher dose of LMWH, mostly. A second limitation is that patients with BMI above 55–60 kg/m2 in Germany were ﬁrst treated with BIB to reduce overall complication rate. Implantation of BIB is most performed without VTE prophylaxis. For laparoscopic interventions, data obtained in a randomized study by Nguyen et al. suggest that hypercoagulability caused a higher incidence of PE [17]. In addition, pneumoperitoneum is a potential risk factor due to the resulting venous stasis of the lower extremity, which is increased by the anti-Trendelenburg position [18]. In German Nationwide Survey, however, this eﬀect could not be detected for RYGBP as well as for SG or GB. According to the data on German Nationwide Survey in BOLD-Registry there was no inﬂuence of operation on the incidence of VTE. BOLD Registry shows an incidence of VTE after GB of 0.16% and after BPD of 5.56%. Risk for VTE was higher if operation was performed at laparoscopic approach (1.53% versus 0.34%) [15]. In German Nationwide Survey in patients with BMI of 45 kg/m2 to 49.9 kg/m2 the highest risk of VTE and PE was observed. Patients developing PE were in average 4.9 years older, had on average an 3.9 kg/m2 higher BMI, and had a higher incidence of VTE in medical history 16.5% versus