Chemical prophylaxis to prevent venous thromboembolism in morbid obesity: literature review and dosing recommendations

Abstract

Pharmacologic prophylaxis of deep vein thrombosis and venous thromboembolism (VTE) is an important aspect of medical care, particularly in the inpatient setting. Low-molecular weight heparins, heparin, and fondaparinux are commonly used agents to prevent VTE, each of which has well established dosing regimens in patients with normal body mass index. Dosing of these medications in morbidly obese populations (BMI > 40 kg/m(2)) is not as clearly defined in guidelines. This article reviews published data to support specific dosing regimens and monitoring strategies of these agents in this population. The most validated parenteral agent to prevent VTE in morbidly obese hospitalized patients is enoxaparin, dosed at 40 mg subcutaneously (SC) twice daily. If unfractionated heparin is utilized for prophylaxis in morbidly obese patients, a dose of 7500 units SC three times daily should be considered. Monitoring of anti-factor Xa levels to guide prophylactic dosing is an option, although the utility of this lab test is limited, as target anti-Xa ranges for VTE prophylaxis have not been universally defined and trials have not shown a clear link between anti-factor Xa levels and bleeding or thrombotic events. Additional studies are needed to clearly define the most appropriate dosing strategies in patients with moderate obesity (BMI 35-40 mg/m(2)) and those with extreme obesity (BMI > 60 mg/m(2)).

Perioperative management of the obese surgical patient

“…126,[128][129][130][131][132][133][134] The already high risk for VTE is further exacerbated with progressively higher BMI, prolonged surgical time, older age, male sex, history of OSA, obesity hypoventilation syndrome and a previous history of VTE. 129;134,135 According to the 2013 Clinical Practice guidelines for bariatric surgical patients, it is recommended that VTE prophylaxis, including sequential compression devices and chemoprophylaxis, to be administered perioperatively.…”

Morbid obesity and perioperative complications

“…Obesity is recognized as an independent risk factor for perioperative venous thromboembolism (VTE) [29][30][31][32][33][34]. Recent ACS-NSQIP database analysis finds that a BMI at least 40 kg/m 2 significantly increased the odds of VTE after CABG, total hip arthroplasty, colectomy, prostatectomy, and pancreatectomy [6 && ].…”

“…Recent ACS-NSQIP database analysis finds that a BMI at least 40 kg/m 2 significantly increased the odds of VTE after CABG, total hip arthroplasty, colectomy, prostatectomy, and pancreatectomy [6 && ]. Clinical Practice Guidelines for the Prevention of VTE in nonorthopedic surgical patients state that most bariatric surgery patients are at high risk for VTE [35], and this risk increases with higher BMI (particularly 40 kg/m 2 ), prolonged operative time, older age, male sex, and history of OSA, obesity hypoventilation syndrome, or VTE [30,35,36]. The 2013 Clinical Practice Guidelines for bariatric surgery patients recommend VTE prophylaxis for all bariatric patients (sequential compression devices as well as chemoprophylaxis), with continued chemoprophylaxis after hospital discharge for highrisk patients [19 && ].…”

Profilaxia do tromboembolismo venoso em cirurgia bariátrica

“…Apparently, therefore, either enoxaparin at a dosage of 40 mg twice a day or fondaparinux (5mg/day) can be recommended for patients with BMI > 40 kg/m . [18][19][20] According to the same review mentioned above, 17 the 0.5 mg/kg enoxaparin regimen is associated with a greater degree of inconvenience, since it has been validated much less and is prone to dosage errors, and because the presentation of enoxaparin is in ready-to-use syringes in fixed doses, making it difficult to divide into smaller doses. The UFH dose recommended in the review was 7,500 IU SC (2 or 3 times a day), based on a retrospective study with a large number of patients.…”

“…17 In addition to obesity and the bariatric surgery itself, several other risk factors can be linked with VTE and should be taken into consideration in relation to decisions on dosage regimen and additional mechanical prophylaxis: …”