Saudi Journal of Obesity

: 2019  |  Volume : 7  |  Issue : 1  |  Page : 1--7

Portomesenteric thrombosis after bariatric surgery in the Pan-Arab region

Ahmad Bashir, Ahmed Maasher, Mousa Khoursheed, Mohammad Alnaami, Alaa Alhazmi, Hayssam Fawal, Aayed Alqahtani, Emad Abdallah, Ayman El-Nakeeb, Ramzi Alami, Bassem Safadi, Mohammed Alkuwwari, Moataz Bashah, Davit Sargasyan, Ahmed Abdelwahid, Safwan Taha, Fuad Ahmed, Ra’ed Fayez, Ashraf Moghraby, Ali Al-Montashery, Mohammad Haddad, Abdelrahman Nimeri 
 Pan-Arab Bariatric Surgery Research Group, Atrium Health, Charlotte, NC

Correspondence Address:
Abdelrahman Nimeri
Associate Professor & Section Chief of Bariatric Surgery, Bariatric Fellowship Program Director, Atrium Health, Charlotte


Background: Bariatric surgery has been shown to be the most effective method to treat morbid obesity and obesity-related comorbidities compared to intensive medical therapy. However, bariatric surgery is not without complications. Some rare complications after bariatric surgery are underestimated. One of these rare complications is portomesenteric thrombosis (PMT). We herein examine the prevalence of PMT after bariatric surgery in the Pan-Arab region. Methods: We sent a questionnaire to the members of the Pan-Arab Bariatric Society for Metabolic and Bariatric Surgery in 2014. This is a group that started on social media in 2012, that represents surgeons practicing in the following countries: United Arab Emirates (UAE), Kingdom of Saudi Arabia (KSA), Qatar, Bahrain, Oman, Kuwait, Egypt, Iraq, Palestine, Jordan, and Lebanon. The questionnaires were sent by email and placed on a link on the Facebook page of the group, and reminders were sent through social media to the members of the group and in our monthly Tele-video conference meeting. All data of procedures carried out in the Pan-Arab region were included. Any procedures performed outside the region were excluded. Results: We sent 77 and received back 18 completed questionnaires (23.4%). The data represent 21 surgeons from 13 hospitals in 9 countries (Iraq, Palestine, UAE, Qatar, Lebanon, Jordan, KSA, Egypt, Kuwait). Data for patients operated in Austria and in the United States were excluded. We received no responses from Bahrain, Iraq, or Oman. The total number of cases performed was 13,274, 9% laparoscopic adjustable gastric banding, 68% laparoscopic sleeve gastrectomy (LSG), 17% laparoscopic Roux-en-Y gastric bypass, 3% one anastomosis gastric bypass/mini gastric bypass, 1% laparoscopic greater curvature plication, 1% biliopancreatic diversion, and 2% others. Our surgeons encountered 30 PMT cases (0.23%). PMT was in both the portal and mesenteric veins in 57% of patients. The rest was observed in either the portal or mesenteric veins. History of travel was found to be associated with PMT in 7/30 [23%]. PMT cases were observed after all procedures, however, mostly after LSG 25/30 (83%). Our practice of deep vein thrombosis prophylaxis is quite variable before and after surgery in different countries. However, most patients with PMT received anticoagulation for less than a week (1–6 days and most of them were on unfractionated heparin 2–3 times/day, or low molecular weight heparin 40 mg once daily during their hospital stay). All patients with PMT complained of abdominal pain in the first 1 to 4 weeks after surgery. Computed tomography scan detected PMT in all except one patient, who was diagnosed by abdominal ultrasound. Two patients required surgical resection of the small bowel and all others were treated medically with anticoagulation. There were no mortalities. Conclusion: PMT is an uncommon complication after bariatric surgery. However, a high index of suspicion is needed to detect this complication. It is most commonly observed after LSG outcome with appropriate intervention is favorable. Majority of patients can be treated without surgical intervention.

How to cite this article:
Bashir A, Maasher A, Khoursheed M, Alnaami M, Alhazmi A, Fawal H, Alqahtani A, Abdallah E, El-Nakeeb A, Alami R, Safadi B, Alkuwwari M, Bashah M, Sargasyan D, Abdelwahid A, Taha S, Ahmed F, Fayez R, Moghraby A, Al-Montashery A, Haddad M, Nimeri A. Portomesenteric thrombosis after bariatric surgery in the Pan-Arab region.Saudi J Obesity 2019;7:1-7

How to cite this URL:
Bashir A, Maasher A, Khoursheed M, Alnaami M, Alhazmi A, Fawal H, Alqahtani A, Abdallah E, El-Nakeeb A, Alami R, Safadi B, Alkuwwari M, Bashah M, Sargasyan D, Abdelwahid A, Taha S, Ahmed F, Fayez R, Moghraby A, Al-Montashery A, Haddad M, Nimeri A. Portomesenteric thrombosis after bariatric surgery in the Pan-Arab region. Saudi J Obesity [serial online] 2019 [cited 2022 Aug 14 ];7:1-7
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Full Text


The prevalence of obesity and type II diabetes mellitus in the Pan-Arab region is among the highest in the world.[1] Bariatric surgery has been shown to be the most effective method to treat both conditions compared to intensive medical therapy.[2] Bariatric surgery is safe, but not without complications.[3] Portomesenteric thrombosis (PMT) is often over looked because it is rare.[4] It has been described as a complication following bariatric surgery.[4] However, its prevalence, causes, or outcomes remain unclear. We herein examine the prevalence of PMT in the Pan-Arab region represented by the Pan-Arab Surgery Research Group.


We designed a questionnaire that was sent to all the bariatric surgeons in our Pan-Arab social media group in 2014 [Figure 1]. The questionnaire reviewed each surgeon’s total number of cases, type of procedures performed, and the number of PMT cases encountered. It also reviewed certain common risk factors for venous thromboembolic (VTE) events in general, as well the type of deep vein thrombosis (DVT) prophylaxis used in their practice. Each PMT case was studied further regarding age, sex, body mass index (BMI) at surgery, presence of comorbidities, type of procedure performed, use of added intraabdominal insufflation pressure >15 mmHg at the time of the operation, length of surgery, preoperative and postoperative DVT prophylaxis, length of prophylaxis, presenting symptoms and time of onset from surgery, methods of diagnosis, hematologic workup, treatment modalities, duration of treatment, and the outcome with follow up studies after treatment if any were done. We sent the questionnaire to all surgeons in our group at the time of the study, from 9 different Arab countries including: Iraq, Palestine, UAE, Qatar, Lebanon, Jordan, KSA, Egypt, and Kuwait. Surgeons who recently located to the Pan-Arab region and joined the group also received the questionnaire.{Figure 1}

We sent the questionnaire by email to all surgeons. We also placed a link for the questionnaire on our Facebook page: We sent reminders through social media, at the time WhatsApp application, and verbally in our monthly bariatric teleconference. Data from Austria and one Lebanese surgeon, who operated on some patients while practicing in San Francisco, California, USA, were excluded. We received no responses from Bahrain and Oman.

To stratify patients into low, intermediate, and high risk for VTE, we used the validated Caprini score to calculate the Caprini score (1–2 low risk, 3–4 intermediate risk, 4 high risk, >4 very high risk) of each PMT patient and compared each score to the chemoprophylaxis these patients used received[5] [Figure 2].{Figure 2}


We received 18/77 (23.4%) questionnaires back. The total number of surgeons in our group was 77 at the time. The data represented 21 surgeons from 13 different institutions in 9 countries: UAE, KSA, Qatar, Kuwait, Egypt, Lebanon, Jordan, and Austria. The total number of cases was 13,274 cases, laparoscopic sleeve gastrectomy (LSG) was the most common procedure performed: 9066 cases (68%). Other procedures: laparoscopic Roux-en-Y gastric bypass (LRYGB) 2246 (17%), laparoscopic adjustable gastric banding (LAGB) 1139 (9%), whereas one anastomosis gastric bypass/mini gastric bypass (OAGB/MGB), laparoscopic greater curvature plication (LGCP), and biliopancreatic diversion round up the rest of the cases in a smaller percentage. Other section represents revisional procedures [Figure 3].{Figure 3}

The majority of our surgeons encountered at least one case of PMT after bariatric surgery 16/21 (76%). The total number of cases done by those surgeons was 9545 [out of 13,274 (72%)]. The case breakdown shows also a dominant volume of LSG (75%), whereas LRYGB is second (14%) [Figure 4]. Of these, 29 patients had PMT for an incidence of 0.3%.{Figure 4}

Only five surgeons (24%) did not experience any PMT cases. Their case volume total was 3729 [out of 13,247 (28%)]. LSG was performed less often but still leading at 51%, whereas LRYGB 25% and LAGB 21% [Figure 5].{Figure 5}

The overall incidence of PMT was 30/13,274 (0.23%). The most common location was combined portal and mesenteric thrombosis 17/30 (57%). Portal alone was 7/30 (23%), whereas mesenteric alone was 6/30 (20%) [Figure 6]. The male to female ratio was 2:1. Average age was 43.7 years (29–52), and the average BMI was 43.4 kg/m2 (32–60).{Figure 6}

The most common procedure that was carried out in PMT patients was LSG 26/30 (8%) [Figure 7]. The other four were LRYGB 2/30 (7%), LOAGB 1/30 (3%), and LGCP 1/30 (3%). All 30 patients presented with abdominal pain. The average time of presentation was 19.6 days postoperatively (7–120).{Figure 7}

The most common risk factor encountered from the questionnaire was traveling 7/30 (23%) [Table 1]. The use of intraoperative abdominal insufflation pressure (IAP) >15 mmHg and an odds ratio time longer that 120 minutes were equal 5/30 (17%). Others are as noted in [Table 1].{Table 1}

VTE chemoprophylaxis

Patients who had PMT received different VTE prophylaxis regimens in regards to preoperative therapy, duration and frequency of postoperative inpatient therapy, and duration of chemoprophylaxis after discharge [Figure 8].{Figure 8}

Preoperative prophylaxis was not given in two patients (6.7%), whereas 93.3% received unfractionated heparin (UFH) 5000 units, low molecular weight heparin (LMWH), or UFH 7500 Units subcutaneously prior to surgery. In addition, postoperative chemoprophylaxis also varied in type of agent used, dose, frequency, and duration of treatment. About 70% (21/30) PMT patients received chemoprophylaxis after discharge. The average duration was 7.2 days (1–21 days) with majority of the patients (16/21) receiving prophylaxis for <7 days. Only 5 patients (17%) received prophylaxis for 21 days. The different types of chemoprophylaxis used were UFH 5000 Units twice daily (BID) in 5/30 (17%), UFH 5000 Units three times daily (TID) in 8/30 (27%), LMWH 40 mg once daily (QD) 5/30 (17%), and LMWH 40 mg BID in 6/30 (20%). Six patients (20%) had missing data for postoperative prophylaxis [Figure 9].{Figure 9}

Majority of PMT patients 19/30 (63%) had a score of 4 (high risk), 7/30 (23%) had a score of 3 (moderate risk), whereas 1/30 (3%) had a score of 6 (highest risk). Despite the high risk detected by the Caprini scoring system, 19/30 (63%) received UFH twice per day (BID), UFH TID, or LMWH once per day (QD). Only 5/30 (17%) received LMWH twice per day, and 6/30 (20%) had missing prophylaxis data [Figure 2].

All surgeons who did not encounter PMT gave preoperative chemoprophylaxis and used LMWH for patients with Caprini score 5 or greater. On the other hand, 2/5 (40%) of surgeons used UFH TID for postoperative prophylaxis for patients with Caprini score of 3 to 4, 2/5 (40%) used LMWH (Enoxaparin and Tinzaparin) QD, and 1/5 (20%) used LMWH BID. However, the frequency varied, BID dosing for LMWH by 3/5 (60%), whereas Enoxaparin 60 mg once per day in one (20%), and Tinzaparin 4500 Units in one. Majority of surgeons (80%) 4/5 gave prophylaxis after discharge for 14 days [Figure 10].{Figure 10}

All patients who were diagnosed with PMT received anticoagulation for 6 months at least. Patients with genetic predisposing factors were anticoagulated for life 3/30 (10%). Two patients required bowel resection (6.7%). The rest were managed completely nonoperatively. Follow-up after treatment was present in 26/30 (87%) of patients. Ultrasound or computed tomography scan of the abdomen with intravenous contrast was obtained in those patients and revealed complete normal resolution of portomesentric venous anatomy and flow in 23/30 (77%), whereas 3/30 (10%) only had partial resolution. No mortalities were noted in our study.


Our study shows that PMT is a rare complication after bariatric surgery occurring in less than 1% of patients. Similarly, Goitein et al. have examined more than 5000 bariatric operations and found the incidence of PMT after bariatric surgery to be around 0.3%.[4]. Likewise, Salinas et al. examined 1713 cases of LSG and encountered PMT in 1% of patients.[6] Despite PMT occurring in less than 1% of patients following bariatric surgery, there is potential for great morbidity and possibly mortality if the diagnosis of PMT is delayed or missed.[6–8] In our study, we did not encounter any mortality, but 6.9% required small bowel resection.

PMT is not a unique complication after bariatric surgery and it can happen after most laparoscopic procedures.[9] In our study, PMT occurred following all types of bariatric surgery procedures, but were most common after LSG cases. Similarly, Goitein et al. showed that 16/17 PMT happened after LSG.[4]

It is not clear why PMT is more common after LSG; it could be because LSG patients are more prone to nausea and dehydration. In addition, LSG required dissection in the lesser sac close to the splenic vessels and division of the short gastric vessels using energy devices. These energy devices could contribute to thrombus formation when used in the proximity of the splenic vessels.

The most striking finding in our study is the wide variability of chemoprophylaxis protocols in the Pan-Arab region after bariatric surgery especially in high-risk patients (Caprini score of 4 or more). We found that surgeons who did not have patients with PMT were more likely to use other forms of chemoprophylaxis than SQ heparin and were more likely to give preoperative chemoprophylaxis. The use of LMWH was found by the Michigan Collaborative group to be more effective than SQ heparin in bariatric surgery patients without more bleeding complications.[10] In addition, many surgeons were using doses that are considered subtherapeutic for morbidly obese patients (once a day dosing of low molecular weight heparin or twice a day dosing of subcutaneous heparin) especially patients with high risk for VTE (Caprini score 4 or more).[11] Furthermore, most patients went home without chemoprophylaxis and few received chemoprophylaxis for less than a week. The concept of risk assessment as a guide for chemoprophylaxis has been well established in the vascular and orthopedic surgery literature.[5] For example, Nimeri et al. have described reducing VTE using a mandatory risk assessment to guide the use of chemoprophylaxis in general surgery patients including bariatric surgery patients.[12] Our study showed that patients with PMT had longer operations and many patients traveled to have bariatric surgery and back to their home country in the first 2 to 3 weeks after bariatric surgery. None of these patients were placed on extended chemoprophylaxis specifically because they were traveling. It is not clear what is the clinical significance of the history of travel in patients with PMT.

Our study has several limitations; it is a survey with less than 30% response rate. The retrospective nature and the self-reported data might not be accurate. However, the great variability in our chemoprophylaxis is evident. We plan to unify the practice of screening for VTE and chemoprophylaxis after bariatric surgery in the Pan-Arab region.

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Conflicts of interest

There are no conflicts of interest.


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