The results of the present study have shown that within an active thromboprophylaxis program that includes additional measures for higher risk patients, laparoscopic bariatric surgery is associated with a low incidence of clinical VTE. But no consensus has yet been reached on the prophylactic regimen or the optimal LMWH dose and the duration for prophylaxis in the patients undergoing laparoscopic bariatric surgery [7
]. Hamad et al. [10
] described the dose and the duration of LMWH used in this study varied among the study centers. There are few data from randomized controlled trials to determine the optimal prophylactic dose of LMWH in obese patients undergoing bariatric surgery. Kalfarentzos et al. [11
] randomly assigned 60 gastric bypass patients to two different doses of LMWH. The lower dose of 5,700 IU was as effective as the 9,500 IU dose and was associated with fewer bleeding complications. Two studies have questioned the use of a fixed dose, as opposed to a weight-based (mg/kg) dose of LMWH in obese patients [12
]. Frederiksen et al. [14
] demonstrated a strong negative correlation between body weight and the anticoagulant effect of a fixed dose of enoxaparin (40 mg) [15
In one study of 1,025 patients who underwent laparoscopic or open gastric bypass, those who bled were significantly more likely to have received preoperative LMWH versus no VTE prophylaxis for major colon and rectal surgery; LMWH significantly reduce the risk of postoperative VTE but was associated with a significantly greater rate of bleeding-related complications [12
]. Scholten et al. [20
] observed bleeding of 0.3% and 1.1% in patients receiving LMWH 40 mg q 12 hours and 30 mg q 12 hours, respectively. In our study, 193 patients were completed 2-week Clexane therapy (97%). Clexane was stopped in 7 patients due to complications (3%). Four patients had bleeding and 1 patient had reoperation due to leak. Four patients had intraluminal bleeding; among them, two patients stopped bleeding without transfusion, two patients had reoperation. In the latter two cases, bleeding was stopped at the time of reoperation. However, we thought that the bleeding focus of one was on the remnant stomach stapler line, and the other near the mesentery. Yet we could not exclude the cause of bleeding being due to using Clexane, but in every four cases, this bleeding happened on operation day, so we decided that this bleeding is related to the operation itself, not Clexane therapy. In addition, 2 patients had potential Clexane related problems. One patient had epistaxis, and 1 patient had metrorrhagia. There was no severe major bleeding in our study. Also, there was no development of symptomatic VTE. As judged from our study, the problem with thromboembolic complications after obesity surgery seems to be small and infrequent. There are only two prospective studies in the literature on the incidence of thromboembolic disease after obesity surgery using objective testing in addition to the present study [21
]. As judged from these studies, thromboembolic complications appear to be rare after obesity surgery.
Most of bariatric surgeons still use mechanical devices such as sequential compression devices in conjunction with a type of heparin [7
]. Chemical prophylaxis used alone has not been proved to be superior to the use of mechanical devices as prophylaxis against DVT, and some have suggested that the addition of heparin to mechanical devices are used appropriately <50% of the time when indicated for a patient, despite being properly ordered [7
]. Therefore, the use or addition of a type of heparin in addition to mechanical devices seems justified. For this reason, in our study, whole-leg compression stockings and pneumatic compression devices were also used.
A minimum of 6 months follow-up for the analysis of VTE incidence was chosen because the published data have suggested that at that point the risk of postoperative VTE should have return to the basal level. Furthermore, 6 months postoperatively, significant weight loss has usually occurred, thereby reducing the risk of VTE further [22
We accept that our study probably underestimated the true incidence of postoperative VTE after laparoscopic bariatric surgery, because we only included symptomatic patients in our analysis and did not routinely screen for silent VTE using duplex ultrasonography or plethysmography. However, given the low-recorded incidence of VTE in bariatric patients, the cost/benefit advantage of such screening would have been dubious, because it would be unlikely to detect DVTs of clinical significance [21
The limitation of this study is that it is a retrospective design with no randomization. Further, long-term follow-up is necessary to evaluate VTE. Indeed, to establish a consensus guideline for LMWH prophylaxis treatment, a large-scale prospective randomized study is necessary.
In conclusion, the results of our study have demonstrated that a 2-week VTE prophylaxis regimen using LMWH after bariatric surgery is both simple and effective, is safe with very low incidence of VTE and bleeding complications.