High dose subcutaneous unfractionated heparin for prevention of venous thromboembolism in overweight neurocritical care patients

Abstract

Timing and dosing of chemical venous thromboembolism (VTE) prophylaxis in brain injury is controversial. Risk of bleeding while using high dose unfractionated heparin (UFH) in overweight patients to prevent VTE is also unknown. The purpose of this study was to describe the use of subcutaneous heparin 7500 units for VTE prophylaxis in overweight patients. This was a retrospective study comparing patients over 100 kg who received either 7500 units Q8 h (n = 141) (high dose group, HDG), or 5000 units Q8 h (n = 257) (traditional dose group, TDG), of UFH subcutaneously. Both groups had similar rates of bleeding complications. The incidence of drop in hemoglobin by two points in any 24 h was 14 % (20/141) HDG versus 11 % (28/257) TDG; P = 0.33. Hemoglobin drop by two points from baseline was 57 % (81/141) HDG versus 51 % (132/257) TDG; P = 0.24. The need for pRBC transfusion was 26 % (36/141) HDG versus 20 % (52/257) TDG; P = 0.22. An increase in aPTT from baseline by two times was 4 % (5/141) HDG versus 4 % (9/257) TDG, P = 0.59. Discontinuation of heparin therapy for association with progressive bleeding was not documented in any patients. No differences in minor bleeding complications were observed. There was no difference in the incidence of VTE: 5.7 % (8/141) HDG versus 9.3 % (24/257) TDG; P = 0.2. In univariate and multivariable logistic regression analysis, only the time of the initiation of heparin after admission was associated with the occurrence of VTE (median, IQR) 46 h (17-86) HDG versus 105 h (56-167) TDG; OR 1.2 (1.1-1.3); P < 0.001. High dose subcutaneous UFH was not associated with an increased risk of bleeding, nor did it decrease the incidence of VTE in overweight patients.

Safety and Efficacy of High-Dose Unfractionated Heparin for Prevention of Venous Thromboembolism in Overweight and Obese Patients

“…Timing of the first initial dose of heparin has been discussed in previous studies. A statistically and clinically significant decrease in the incidence of VTE was reported if VTE prophylaxis was given within the first 72 hours of admission . These studies have also shown the safety of administering early VTE prophylaxis as well.…”

“…These studies suggested that anticoagulant dosage adjustments in overweight patients may optimize the activity of the drug and reduce VTE risk. Studies have also been published in overweight or obese patients who have not undergone bariatric surgery to evaluate the benefit of high‐dose VTE prophylaxis . The objective of this study was to determine the safety and efficacy of high‐dose subcutaneous unfractionated heparin (UFH) for prevention of VTE in overweight and obese patients.…”

Antifactor Xa levels vs. activated partial thromboplastin time for monitoring unfractionated heparin. A pilot study

“…Major bleeding complications while on UFH infusion were defined as any clinically significant bleeding associated with at least one of the following: documented systemic bleeding in any critical area or organ, haemoglobin drop by >2 g/dL in any 24 h or from baseline and/or need for blood transfusion with at least 2 units of blood. Minor bleeding such as epistaxis, ecchymosis or haematuria was also documented …”

Assessment of the Relationship between Body Mass Index and Incidence of Venous Thromboembolism in Hospitalized Overweight and Obese Patients

“…We then developed a database that included those who weighed more than 100 kg and received only unfractionated heparin (UFH) for VTE prophylaxis. We analyzed the data by comparing the groups who received traditional dosing with UFH 5000 units every 8 hours with those who received high‐dose UFH 7500 units every 8 hours for VTE prophylaxis . In this preliminary study, we found a nonsignificant difference between VTE rates in the two groups.…”

“…Because current evidence suggests that the relationship between body mass index (BMI) and incidence of venous thromboembolism (VTE) is linear, the risk for VTE rises as BMI increases . The incidence of VTE was reported to range from 0.1–42% in patients in all BMI subgroups who were either hospitalized (1.43–15%) or seen as outpatients (0.1–42%) . Obesity is suspected to be one of the risk factors for VTE, and the incidence of VTE increases by 6‐fold when BMI exceeds 35 kg/m 2 .…”