European Journal of Cardiovascular Medicine

Nowadays, a large number of bariatric surgery (BS) procedures are undertaken worldwide as surgery has become an efficient strategy to treat the obesity epidemic. The risk of venous thromboembolism (VTE) is increased in patients undergoing BS not only due to the intrinsic surgical risk but also because patients with obesity have a 2-3-fold higher risk of VTE. The optimal strategy for VTE prevention in BS setting, including optimal dose and thromboprophylaxis regimen, is still not fully clarified. The aim of this study was to report a bariatric high-volume center experience and to propose a practical thromboprophylaxis protocol for this population.

Bariatric surgery patients have a two-fold increased risk for VTE events. Obesity is itself a hypercoagulability state, frequently associated with hypertension (HTN), obstructive sleep apnea (OSA), and venous stasis, which are known risk factors for VTE-related complications. On the other hand, bariatric surgery comprises a range of complex procedures. The extended operative time, the occurrence of surgical complications, the need for surgical reinterventions, and even blood transfusions are risk factors for VTE events.

Various strategies have been used to prevent VTE in bariatric surgery patients, including pharmacologic and mechanical thromboprophylaxis. However, the optimal strategy, including thromboprophylaxis regimen, remains uncertain.

The impact of bariatric surgery with a consecutively altered anatomy on pharmacokinetics and pharmacodynamics of a single prophylactic dose of rivaroxaban has been investigated in 2 previous phase 1 clinical trials. In these studies, altered postbariatric anatomy and weight loss did not affect pharmacokinetic and pharmacodynamic parameters of rivaroxaban in a clinically relevant way. However, to our knowledge, no prospective randomized clinical trial has investigated the use of DOACs after upper gastrointestinal tract surgery, including bariatric procedures. Therefore, we designed and conducted the BARIVA (Bariatric Rivaroxaban) trial to investigate the efficacy and safety of a prophylactic dose of rivaroxaban in a randomized setting (7- vs 28-day prophylaxis) in patients after bariatric surgery.

The aim of this paper was to report the experience of a high-volume bariatric center in the prevention of venous thromboembolic events and to propose a standard thromboprophylaxis protocol for this specific population undergoing bariatric surgery.

People undergoing Bariatric surgery have increased globally. Currently no clear anti-coagulation prophylaxis protocol exists in bariatric surgical practice. Need to have standardized protocol regarding anti-coagulation prophylaxis

AIM

To suggest protocol regarding anti-coagulation prophylaxis perioperatively including its duration and dose.

Database searches were collected retrospectively from August 2018 to November 2021. Patient follow-up record collected till 6 months post-surgery. All patients underwent pre bariatric surgical profile – including coagulation profile, maintained good hydration 3 hrs prior to surgery by starting IV fluids including colloids, Mechanical and chemical prophylaxes were provided perioperatively for all patients as per institutional protocol.

Inclusion criteria

Bariatric patients posted for RYGB, MGB, LSG, DJB, Ileal interposition and revisional surgeries

Exclusion Criteria

Balloon endoscopy

Data collected- age, gender, body mass index (BMI), lower limb edema, Dyslipidemia, duration of anti-coagulation prophylaxis, type of surgery, postoperative morbidity and mortality.

Patients were mobilized immediately 2 to 3 hrs after surgery. All patients were given 40mg enoxaparin (LMWH) SC prophylactic dose, 12 hrs before surgery and 8 hrs after surgery and continue every 24 hrs till discharge. In high risk patients LMWH or oral anticoagulants were given for longer duration after discharge.

High risk patients categorized by 1) Super obese patients with BMI more than 50, 2) previous history of DVT/PE, 3) female patients with OC pills, 4) Immobile and limited mobility patients, 5) patients with Chronic limb edema and large varicose veins

Those patients on oral anticoagulants were converted to LMWH 3 days prior to surgery. Some patient who was immobile post surgery anticoagulant either LMWH (40mg) or oral anticoagulant were supplemented up to 3 months

The ACCP guidelines utilize the VTE risk stratification systems by Rogers and Caprini very low risk patients - ambulation without chemoprophylaxis or mechanical prophylaxis low risk patients - mechanical prophylaxis with intermittent pneumatic compression (IPC).

Moderate risk - low molecular weight heparin (LMWH), unfractionated heparin (UH), or mechanical prevention with IPC.

High risk patients- LMWH or UH plus elastic stockings or IPC. Despite the elevated VTE risk, the incidence of postoperative VTE is low. Mean incidence of PE of 0.5% with fixed-dose chemo prophylaxis and an incidence of symptomatic VTE of 0.6% with weight-based chemo prophylaxis.^[1] Fotis et al found no statically significance difference found regarding dose of LMWH.^[2]

The risk of VTE is lower for laparoscopic compared with open bariatric surgery patients (0.34% versus 1.54%). dosing by body weight may lead to excessive anti-coagulation and bleeding.^[3]

Andrew et al- bedridden >3 days – significant risk factor for DVT.^[4] Eugene et all mentioned Risk of VTE can be decreased significantly by early mobilization, mechanical compressive device and anti-coagulation prophylaxis.^[5]

Grissel et al reported 0.9% incidence of pulmonary embolism and 0.1% incidence of DVT. In our study we reported 0% incidence of DVT and 0% incidence of Pulmonary embolism.^[6]

To our knowledge, this is the first trial in which an oral factor Xa inhibitor has been prospectively investigated in patients after gastrointestinal surgery in general and in bariatric surgery in particular. The results of this randomized clinical trial indicate that thromboprophylaxis with 10 mg/d of rivaroxaban is efficacious and safe in the postoperative setting of bariatric surgery. The overall number of primary end point events was very low (1 single asymptomatic DVT in a patient undergoing SG with 28-day prophylactic treatment). Therefore, no significant difference between the 2 treatment groups regarding the primary composite end point (symptomatic or asymptomatic DVT and PE) could be detected. Although the altered anatomy after bariatric surgery is of some theoretical concern, no relevant effect on pharmacokinetic parameters could be observed in previous phase 1 studies.^[7,8]

Risk of VTE can be decreased significantly by use of proper protocol early mobilization immediately 2 hrs after surgery and use of mechanical compressive device during period of anesthesia and immobilization.

Use of SC LMWH 40mg (irrespective of BMI) 12hr prior and 8 hrs after surgery then continued every 24 hrs till discharge. In high risk cases LMWH or oral anticoagulant needed for extended period up to 3 months.

In patients who are on oral anticoagulant before surgery, we continue postoperatively.

1. VTE Prophylaxis for Laparoscopic Surgery Guidelines: An Update Board of Governors of the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) in Mar 2017.
2. William S.Obesity Surgery Fotis Kalfarentzos et al December 2001, Volume 11, Issue 6, pp 670–676 | Cite as Prophylaxis of Venous Thromboembolism Using Two Different Doses of Low-Molecular-Weight Heparin (Nadroparin) in Bariatric Surgery: A Prospective Randomized Trial\
3. VTE Prophylaxis for Laparoscopic Surgery Guidelines: An Update Board of Governors of the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) in Mar 2017.Authors William S.
4. The Wells DVT criteria: Clinical prediction model for deep vein thrombosis [Classics Series] November 26, 2012 | Andrew Cheung, MD
5. Eugene C Wu Carlos A Barba et al February 2000, Volume 10, Issue 1, pp 7–13 | Cite as Current Practices in the Prophylaxis of Venous Thromboembolism in Bariatric Surgery 2) SAGES guidelines March 2017
6. Obesity Surgery November 2005, Volume 15, Issue 10, pp 1368–1374 | Cite as Enoxaparin for Thromboprophylaxis in Morbidly Obese Patients Undergoing Bariatric Surgery: Findings of the Prophylaxis Against VTE Outcomes in Bariatric Surgery Patients Receiving Enoxaparin (PROBE) Study Giselle G HamadPatricia Smith Choban
7. Kröll D, Nett PC, Borbély YM, et al. The effect of bariatric surgery on the direct oral anticoagulant rivaroxaban: the extension study.  Surg Obes Relat Dis. 2018;14(12):1890-1896. doi:1016/j.soard.2018.08.025PubMedGoogle ScholarCrossref
8. Kröll D, Stirnimann G, Vogt A, et al. Pharmacokinetics and pharmacodynamics of single doses of rivaroxaban in obese patients prior to and after bariatric surgery.  Br J Clin Pharmacol. 2017;83(7):1466-1475. doi:1111/bcp.13243PubMedGoogle ScholarCrossref