World Health Organization (WHO) data show that about 11% of the world population suffers from obesity (body mass index above 30 kg/m². In the US, it is considered a major public health problem, affecting more than one third of the adult population [1]. According to the Brazilian Ministry of Health (MH), the percentage of adults overweight is 51% [2].

The clinical treatment of morbid obesity with low-calorie diets and changes in lifestyle with or without pharmacological therapy does not present good results when compared to surgical treatment, now considered the gold standard [3] [4] [5].

Among surgical procedures, the most performed techniques are gastric bypass and sleeve gastrectomy, being surgeries safe, with greater maintenance of weight loss and lower rates of complications. However, surgeons should be aware of all possible complications [6] [7] [8] [9].

Of the possible postoperative events, we focus on the complication that every surgeon should be aware of in patients with abdominal symptoms after undergoing bariatric surgery: portal vein thrombosis (PVT) and the superior mesenteric vein thrombosis (SMVT), previously uncommon in other abdominal surgeries with similar complexities.

Portal vein thrombosis is a very uncommon complication after laparoscopic surgery. The development of thrombosis and coagulation disorders in patients undergoing laparoscopy with pneumoperitoneum has been described previously, but thrombosis of the portal vein (PVT) and the superior mesenteric vein (SMVT) is not a common complication after laparoscopic surgery.

In this report, we present five cases of PVT and one case of SMVT, after laparoscopic bariatric surgery, operated at this facility, reporting the clinical features and treatment of patients involved in such addressed complication.

There was a retrospective analysis of 4790 patients who underwent laparoscopic bariatric surgery at São José do Avaí Hospital (HSJA) from August 1999 to June 2020. Of these, 72.5% (n = 3473 patients) underwent laparoscopic gastric bypass (LGBP), 23.6% (n = 1131 patients) were submitted to the laparoscopic sleeve gastrectomy (LSG) and 3.8% (n = 186 patients) to other procedures.

Of all patients, 72.8% were female and 27.2% male. The mean age was 46.3 years (34 - 72) and the mean BMI before bariatric surgery was 41.4 kg/m².

The types of variables used in the study were gender, age, BMI and the surgical techniques were LGBP or LSG or other procedures. Data was based on median, analyzing minimum and maximum values, organized in percentage. Data was collected using the Exemplo Medical program, version eMD Central 7.

Surgical indication followed the criteria was defined by the 1991 Consensus; BMI > 40 kg/m² and/or BMI > 35 kg/m² associated with comorbidities. All patients were evaluated by a multidisciplinary team consisting of psychologist, nutritionist, physical therapist, endocrinologist, surgeon and anesthesiologist.

The following exams were preoperatively performed in all cases: Complete blood count and platelet parameters, serum urea, creatinine, glucose, prothrombin time, alanine aminotransferase (ALT), aspartate aminotransferase (AST), ferritin, vitamin B12, magnesium, zinc, selenium, 25 (OH) vitamin D3, serology for hepatitis B and C, blood gas analysis, lipid profile, upper endoscopy with urease test, total abdominal ultrasound, bone densitometry and echocardiography. Mammography, prostate antigen or follicle stimulating hormone, myocardial scintigraphy and Doppler carotid arteries were performed in selected cases.

The surgical technique used for gastric bypass was the making of a gastric pouch, cutting the stomach with 3 or 4 applications of the linear stapler. The jejunum was sectioned at a location 50 cm from the Treitz angle with 1 application of the linear tapler. A 100-cm-long Roux limb was used. A lateral jejunojejunostomy was done with 1 load of the linear stapler and completed with hand-sewn stitches. The distal jejunum was anastomosed to the gastric pouch by gastrojejunostomy (G-J anastomosis), performed via the antecolic antegastric route, using the flip-top 25-mm circular stapler or applications of the linear stapler, and tested by injecting 50 mL of methylene blue through the nasogastric tube, closing the mesenteric spaces with hand-sewn stitches.

Sleeve gastrectomy was performed releasing the gastroepiploic arcade of vessels up to about 5 cm from the pylorus, introduction of orogastric tube 36 Fr size, sleeve gastrectomy was done with six to eight linear staplers loads, reinforce the staple line with running sutures using 3.0 polypropylene.

The prevention of thromboembolic events was performed in patients with BMI 35 to 49.9 by air compressors in the legs intraoperative and early ambulation 3 - 4 hours after surgery and in each hour after.

Drug prophylaxis was used in selected patients considered as high risk, such as a history of deep venous thrombosis, lympho venous stasis, previous episode of erysipelas of the lower limbs and/or postphlebitic syndrome, patients with atheromatous plaque in the carotid arteries and/or atrial fibrillation and super obese patients (BMI > 50 kg/m²). These patients received pharmacological prophylaxis with 5000 IU of unfractionated heparin, SC 8/8h, postoperatively.

PMVT patients seek assistance in the emergency room of our hospital or reported symptoms at the follow-up visit, were admitted for investigation and further tests were performed: CT scan with venous contrast, blood tests, blood tests for thrombosis: PT-INR, activated partial thromboplastin time (aPTT), fibrinogen level, complete blood count (CBC), genetic tests, including factor V Leiden (activated protein C resistance) and prothrombin gene mutation , antithrombin activity, protein C activity, protein S activity, fasting plasma homocysteine levels.

The selected patients were all those who had previously undergone bariatric surgery, with nonspecific symptoms, including nausea, abdominal pain, abnormal bowel movement, malaise, asthenia and fever. The diagnosis of thrombosis was confirmed by radiological imaging (CT scan with venous contrast, angiography) associated with the laboratory tests mentioned above.

After the diagnostic, patients were rehydration and bowel rest, were treated by full anticoagulation with subcutaneous low-molecular-weight heparin or intravenous unfractionated heparin, followed by oral coagulant that should be continued for several months.

Data were obtained with the help of software Exemplo Medical program, version eMD Central 7.

The variables are summarized using median, minimum, maximum values and percentages.

In the images below it is possible to observe and diagnose three patients with PVT or SMVT using CT scan with venous contrast.

In Figure 1 is coronal section evidencing the absence of the passage of contrast in the portal vein since its origin (SMVT).

In Figure 2 is coronal section in the portal phase, showing no opacification of the portal vein by means of contrast (PVT).

In Figure 3 there is an axial section of the CT scan with venous contrast evidencing failure in filling of the mesenteric vein at the junction with the splenic vein.

There was a retrospective analysis of 4790 patients who underwent laparoscopic bariatric surgery from August 1999 to June 2020. The mean age was 46.3 years, and on the day of bariatric surgery the average BMI was 41.4 kg/m² and on the day of PMVT the average BMI was 26.6 kg/m².

Of these, 72.5% (n = 3473 patients) underwent gastric bypass, 23.6% (n = 1131 patients) were submitted to the sleeve gastrectomy and 3.8% (n = 186 patients) to other procedures.

The six patients evolved in this study haven’t presenting any preoperative history for hypercoagulable, intraoperative and early postoperative complications.

Patients showed: leukocytosis with a left shift, and abdominal CT with intravenous contrast where thrombi were diagnosed (Figures 1-3).

Out of our 6 patients, the additional laboratory tests in a patient (16.6%) showed anti-thrombin III of 58%; positive lupus anticoagulant.

The study revealed an incidence of PMVT of 0.12% (6 patients), PVT of 0.10% (5 patients) and 0.03% of MVT (1 patients). We observed that three (50%) patients had undergone gastric bypass and three (50%) underwent sleeve gastrectomy.

The operative time ranged from 55 min to 210 min, with average time 123 min. The mean postoperative hospital stay after bariatric surgery was 4.3 days (range 2 - 10). After undergoing bariatric surgery, the patients in this study had an average time of readmission with a diagnosis of PMPM of 285.5 days, ranging from 7 to 638 days.

The average length of hospital stay after PMVT was 8.3 days, ranging from 7 to 14 days (Table 1).

*Systemic arterial hypertension; **CT with intravenous contrast the patient IV (Figure 1); ***CT with intravenous contrast Patient V (Figure 2, Figure 3).

There was late complication in three patients, patient number I: esophageal varices after four months, patient number III: cavernous transformation of the portal vein with turbulent flow and splenomegaly after 11 months, patient number VI: after one year in upper digestive endoscopy, presented large-caliber varicose veins in the lower 1/3 of the esophagus, that bleed, need endoscopic variceal ligation, low platelet (59 thousand), splenomegaly, had normal elastography and normal liver function tests.

No patient died due to complications related to PMVT.

The actual incidence of post-surgical PMVT is not clearly determined and especially by the unknown number of subclinical and undiagnosed cases [10].

PMVT has been reported after laparoscopic surgery such as cholecystectomy, right hemicolectomy, fundoplication and splenectomy [11] [12]. The pathophysiological mechanism and the specific risk factors remain unclear. Pigeyre M. published a case report of vein thrombosis port associated with severe neuropathy vitamin deficiency in patients submitted to bypass [13]. Bruno Berthet et al. reported a case of PVT in patients with mutation in Leiden factor 2 who underwent sleeve gastrectomy [14]. Out of our 6 patients who showed this of complication, in the additional laboratory investigations only one showed anti-thrombin III of 58%; positive lupus anticoagulant.

It is believed that the increased risk of splanchnic vessels thrombosis is due to changes in hemodynamic conditions determined by pneumoperitoneum, which includes visceral vasoconstriction, secondary to vasopressin secretion; anti-Trendelenburg position, commonly used in laparoscopic surgery; and the increase of portal pressure by CO₂ retention [15] [16] [17]. Obesity may play a supporting role in the development of venous thromboembolism in hospitalized patients with other risk factors [18].

Another theory, after bariatric surgery, patients are usually discharged from the hospital early after the procedure. Some patients find it difficult to ingest the amount of fluids suggested at 2 L/d and experience varying degrees of dehydration. Being able to put them at greater risk of thrombotic complications such as DVT, pulmonary embolism and PMVT [19] [20].

In my point of view, complex surgical procedures by laparoscopy have never been performed on patients at high risk for thrombotic events and with routine monitoring for so many years. Probably due to these facts, we diagnosed PMVT more frequently. The most recent IFSO Worldwide Survey) reported that 634,897 bariatric operations were performed worldwide in 2016 [21].

PMVT is an uncommon surgical complication secondary to laparoscopic bariatric surgery. In 20% to 35% of cases, LSG remains the primary cause of PMVT [22]. However, in this study, we found PMVT in 50% of patients submitted to LGBP and 50% to LSG.

Goitein D et al. showed in their multicenter studies an incidence of 0.3% of PMVT after laparoscopic bariatric surgery, they used routinely venous thrombotic event prophylaxis [23]. Prophylaxis related to venous thrombotic events were used in all papers that studied the emergence of PMVT, however, it did not prevent this complication in any patient [24].

In the present study, routinely prophylaxis for venous thrombotic events was not used for low-risk patients, which suggests that non-pharmacological prophylaxis does not increase the incidence of PMVT as deep vein thrombosis [25] [26]. The number of patients with this pathology was 0.12% lower than the literature.

The diagnosis of PVT or SMVT postoperatively is often difficult. The symptoms are nonspecific. Among them we mention nausea, vomiting, abdominal pain, changes in bowel movement and fever. When in doubt, laboratory tests are requested, also nonspecific, where leukocytosis may be present. Prolongation of prothrombin time (PT) and falling levels of protein S suggest vitamin K deficiency, which predisposes the body to thromboembolic events, in patients with a history of treatment for phlebitis [27]. To confirm the diagnosis, CT scan with intravenous contrast, angiography, is the best method to assess cases. Literature reviews show that treatment of choice is the immediate intravenous anticoagulation, followed by oral anticoagulation, the latter being maintained for at least 3 to 6 months. Clinical follow-up should be performed by the clinical evaluation of the patient, INR and CT series. Other treatment options include thrombolysis catheter, percutaneous balloon dilation or stent, however for PMVT, those therapy is ineffective [28]. The main complication is cavernous transformation of the portal vein [13] - [28]. All our patients had diagnostic confirmation with CT scan with venous contrast and therapeutic success with anticoagulation without the need for additional therapies. However, we found late complications in 50% of the patients: patient number I: esophageal varices after four months, patient number III: cavernous transformation of the portal vein with turbulent flow and splenomegaly after 11 months, patient number VI: after one year in upper digestive endoscopy, presented large-caliber varicose veins in the lower 1/3 of the esophagus and splenomegaly.

Portomesenteric vein thrombosis is a rare presentation after laparoscopic bariatric surgery. However, it is a serious complication that has a high index of suspicion for making its diagnosis. Conservative treatment using anticoagulants and thrombolytics is effective, it should always be considered the main treatment option. However, these patients must be followed up in the long term, as late complications can occur in high numbers of patients.

The authors declare that they have no conflict of interests.

Tinoco, A., Tinoco, R.C., El-Kadre, L., Netto, M.P.S., Rocha, J.M., de Souza, D.R. and Tavares, D.G. (2022) Portomesenteric Venous Thrombosis in Patients after Laparoscopic Bariatric Surgery. Surgical Science, 13, 419-428. https://doi.org/10.4236/ss.2022.139050