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
]. The risk for thromboembolic complications in bariatric surgery in patients who did not receive in-hospital chemoprophylaxis is 2.4% [12
]. 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
]. 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
]. 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 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
]. 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 operations 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, BMI >60
kg/m², and previous history of venous thromboembolism [11
For high-risk patients with a BMI >50
kg/m², a medical history of VTE, surgical interventions at the pelvis, and heart failure in further studies, the positive effect of an IVC filter was found [26
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
]. The current ASMBS statement recommends performing compression therapy and medication for the prophylaxis of thromboembolism. The AWMF guidelines classify patients with a BMI >30
kg/m² as high risk, but there is a lack of appropriate recommendations for the prophylaxis of thromboembolism in bariatric surgery [6