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Bruno AM, Allshouse AA, Campbell HM, Branch DW, Lim MY, Silver RM, Metz TD. Weight-Based Compared With Fixed-Dose Enoxaparin Prophylaxis After Cesarean Delivery: A Randomized Controlled Trial. Obstet Gynecol 2022; 140:575-583. [PMID: 36075079 PMCID: PMC10473241 DOI: 10.1097/aog.0000000000004937] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 07/14/2022] [Indexed: 01/05/2023]
Abstract
OBJECTIVE To evaluate fixed compared with weight-based enoxaparin dosing to achieve prophylactic anti-Xa levels after cesarean delivery. METHODS Individuals meeting institutional criteria for enoxaparin thromboprophylaxis after cesarean delivery were randomly allocated to fixed (40 mg daily for body mass index [BMI, calculated as weight in kilograms divided by height in meters squared] lower than 40; 40 mg every 12 hours for BMI 40 or higher) or weight-based (0.5 mg/kg every 12 hours) enoxaparin dosing. Enoxaparin was initiated during inpatient hospitalization and continued at discharge for 14 days. Those with contraindication to anticoagulation, plan for therapeutic anticoagulation, or known renal impairment were excluded. The trial was unmasked. The primary outcome was prophylactic (0.2-0.6 international units/mL) peak anti-Xa level 4-6 hours after at least the third enoxaparin dose (at steady state). Secondary outcomes included subprophylactic and supraprophylactic peaks, outpatient peak, and venous thromboembolism (VTE) and wound complications in the first 6 weeks postpartum. Sample size of 121 per group was planned. At interim analysis with 50% enrollment, the trial was stopped early for efficacy. Primary analyses followed intention-to-treat principle with worst-case imputation for missing outcomes. Secondary analyses were complete case. RESULTS From June 2020 to November 2021, 74 individuals were randomized to weight-based enoxaparin and 72 to fixed-dose enoxaparin. Those who received weight-based dosing were more likely to achieve prophylactic anti-Xa levels than those who received fixed dosing in primary analysis (49/74 [66%] vs 32/72 [44%], relative risk [RR] 1.49, 95% CI 1.10-2.02) and secondary analysis (49/60 [82%] vs 32/57 [56%], RR 1.45, 95% CI 1.12-1.88). Subprophylactic levels occurred more frequently with fixed dosing; supraprophylactic levels did not differ significantly by dosing. At the outpatient postoperative visit, 52% of participants (15/29) with weight-based dosing compared with 15% (5/33) with fixed dosing achieved prophylactic peak anti-Xa level (RR 3.41, 95% CI 1.42-8.24). There were no VTEs in either group. Wound complications occurred in five individuals (7%) with weight-based enoxaparin dosing compared with one individual (1%) with fixed enoxaparin dosing (RR 4.86, 95% 0.58-40.63). CONCLUSION Weight-based dosing was more effective than fixed enoxaparin dosing in achieving prophylactic peak anti-Xa levels after cesarean delivery. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, NCT04305756.
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Affiliation(s)
- Ann M. Bruno
- University of Utah Health, Salt Lake City, UT
- Intermountain Healthcare, Murray, UT
| | | | - Heather M. Campbell
- University of Utah Health, Salt Lake City, UT
- Intermountain Healthcare, Murray, UT
| | - D. Ware Branch
- University of Utah Health, Salt Lake City, UT
- Intermountain Healthcare, Murray, UT
| | - Ming Y. Lim
- University of Utah Health, Salt Lake City, UT
| | - Robert M. Silver
- University of Utah Health, Salt Lake City, UT
- Intermountain Healthcare, Murray, UT
| | - Torri D. Metz
- University of Utah Health, Salt Lake City, UT
- Intermountain Healthcare, Murray, UT
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Stanciakova L, Dobrotova M, Holly P, Zolkova J, Vadelova L, Skornova I, Ivankova J, Samos M, Bolek T, Grendar M, Danko J, Kubisz P, Stasko J. How can Secondary Thromboprophylaxis in High-Risk Pregnant Patients be Improved? Clin Appl Thromb Hemost 2022; 28:10760296211070004. [PMID: 35225706 PMCID: PMC8894622 DOI: 10.1177/10760296211070004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Low-molecular-weight heparin (LMWH) is suggested for thromboprophylaxis in
pregnant women with previous venous thromboembolism (VTE). Anyway,
there is only limited amount of studies evaluating the effect of LMWH on
hemostatic parameters during pregnancy of patients with previous VTE and the
need of secondary thromboprophylaxis. We therefore provide results of
prospective and longitudinal assessment of changes in hemostasis in high-risk
pregnant women at four times during pregnancy (T1–T4) and one time after the
postpartum period (T5) used for individualized modification of
thromboprophylaxis. In this study, the results of coagulation factor VIII
(FVIII) and protein S (PS) activity, ProC Global ratio and anti-Xa activity were
evaluated. Despite the thromboprophylaxis, an increased predisposition to
thromboembolic complications was detected (significant increase in FVIII
activity and decrease in PS function, ProC Global ratio not normalized even
after the postpartum period – p < .0001 between controls and
T5 for PS and ProC Global). These results indicate that hemostasis may not be
restored even 6 to 8 weeks after delivery and pose the question when is it safe
to withdraw the anticoagulant thromboprophylaxis in high-risk patients with
prior VTE.
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Affiliation(s)
- Lucia Stanciakova
- National Center of Hemostasis and Thrombosis, Department of Hematology and Transfusion Medicine, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Martin University Hospital, Martin, Slovak Republic
| | - Miroslava Dobrotova
- National Center of Hemostasis and Thrombosis, Department of Hematology and Transfusion Medicine, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Martin University Hospital, Martin, Slovak Republic
| | - Pavol Holly
- National Center of Hemostasis and Thrombosis, Department of Hematology and Transfusion Medicine, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Martin University Hospital, Martin, Slovak Republic
| | - Jana Zolkova
- National Center of Hemostasis and Thrombosis, Department of Hematology and Transfusion Medicine, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Martin University Hospital, Martin, Slovak Republic
| | - Lubica Vadelova
- National Center of Hemostasis and Thrombosis, Department of Hematology and Transfusion Medicine, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Martin University Hospital, Martin, Slovak Republic.,Center of Immunology in Martin, s.r.o., Martin, Slovak Republic
| | - Ingrid Skornova
- National Center of Hemostasis and Thrombosis, Department of Hematology and Transfusion Medicine, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Martin University Hospital, Martin, Slovak Republic
| | - Jela Ivankova
- National Center of Hemostasis and Thrombosis, Department of Hematology and Transfusion Medicine, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Martin University Hospital, Martin, Slovak Republic
| | - Matej Samos
- Department of Internal Medicine I., Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Martin University Hospital, Martin, Slovak Republic
| | - Tomas Bolek
- Department of Internal Medicine I., Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Martin University Hospital, Martin, Slovak Republic
| | - Marian Grendar
- Laboratory of Bioinformatics and Biostatistics, Biomedical Center Martin, Comenius University in Bratislava, 112842Jessenius Faculty of Medicine in Martin, Martin, Slovak Republic.,Laboratory of Theoretical Methods, Institute of Measurement Science, Slovak Academy of Sciences, Karlova Ves, Slovak Republic
| | - Jan Danko
- Department of Gynecology and Obstetrics, 112842Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin and University Hospital in Martin, Martin, Slovak Republic
| | - Peter Kubisz
- National Center of Hemostasis and Thrombosis, Department of Hematology and Transfusion Medicine, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Martin University Hospital, Martin, Slovak Republic
| | - Jan Stasko
- National Center of Hemostasis and Thrombosis, Department of Hematology and Transfusion Medicine, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Martin University Hospital, Martin, Slovak Republic
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3
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Pannucci CJ, Fleming KI, Bertolaccini C, Agarwal J, Rockwell WB, Mendenhall SD, Kwok A, Goodwin I, Gociman B, Momeni A. Optimal Dosing of Prophylactic Enoxaparin after Surgical Procedures: Results of the Double-Blind, Randomized, Controlled FIxed or Variable Enoxaparin (FIVE) Trial. Plast Reconstr Surg 2021; 147:947-958. [PMID: 33761517 DOI: 10.1097/prs.0000000000007780] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The accepted "one-size-fits-all" dose strategy for prophylactic enoxaparin may not optimize the medication's risks and benefits after surgical procedures. The authors hypothesized that weight-based administration might improve the pharmacokinetics of prophylactic enoxaparin when compared to fixed-dose administration. METHODS The FIxed or Variable Enoxaparin (FIVE) trial was a randomized, double-blind trial that compared the pharmacokinetic and clinical outcomes of patients assigned randomly to postoperative venous thromboembolism prophylaxis using enoxaparin 40 mg twice daily or enoxaparin 0.5 mg/kg twice daily. Patients were randomized after surgery and received the first enoxaparin dose at 8 hours after surgery. Primary hypotheses were (1) weight-based administration is noninferior to a fixed dose for avoiding underanticoagulation (anti-factor Xa <0.2 IU/ml) and (2) weight-based administration is superior to fixed-dose administration for avoiding overanticoagulation (anti-factor Xa >0.4 IU/ml). Secondary endpoints were 90-day venous thromboembolism and bleeding. RESULTS In total, 295 patients were randomized, with 151 assigned to fixed-dose and 144 to weight-based administration of enoxaparin. For avoidance of under anticoagulation, weight-based administration had a greater effectiveness (79.9 percent versus 76.6 percent); the 3.3 percent (95 percent CI, -7.5 to 12.5 percent) greater effectiveness achieved statistically significant noninferiority relative to the a priori specified -12 percent noninferiority margin (p = 0.004). For avoidance of overanticoagulation, weight-based enoxaparin administration was superior to fixed-dose administration (90.6 percent versus 82.2 percent); the 8.4 percent (95 percent CI, 0.1 to 16.6 percent) greater effectiveness showed significant safety superiority (p = 0.046). Ninety-day venous thromboembolism and major bleeding were not different between fixed-dose and weight-based cohorts (0.66 percent versus 0.69 percent, p = 0.98; 3.3 percent versus 4.2 percent, p = 0.72, respectively). CONCLUSION Weight-based administration showed superior pharmacokinetics for avoidance of underanticoagulation and overanticoagulation in postoperative patients receiving prophylactic enoxaparin. CLINICAL QUESTION/LEVEL OF EVIDENCE Therapeutic, I.
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Affiliation(s)
- Christopher J Pannucci
- From the Divisions of Plastic Surgery and Health Services Research and the Department of Pharmacy Services, University of Utah; Plastic Surgery Northwest; and the Division of Plastic and Reconstructive Surgery, Stanford University
| | - Kory I Fleming
- From the Divisions of Plastic Surgery and Health Services Research and the Department of Pharmacy Services, University of Utah; Plastic Surgery Northwest; and the Division of Plastic and Reconstructive Surgery, Stanford University
| | - Corinne Bertolaccini
- From the Divisions of Plastic Surgery and Health Services Research and the Department of Pharmacy Services, University of Utah; Plastic Surgery Northwest; and the Division of Plastic and Reconstructive Surgery, Stanford University
| | - Jayant Agarwal
- From the Divisions of Plastic Surgery and Health Services Research and the Department of Pharmacy Services, University of Utah; Plastic Surgery Northwest; and the Division of Plastic and Reconstructive Surgery, Stanford University
| | - W Bradford Rockwell
- From the Divisions of Plastic Surgery and Health Services Research and the Department of Pharmacy Services, University of Utah; Plastic Surgery Northwest; and the Division of Plastic and Reconstructive Surgery, Stanford University
| | - Shaun D Mendenhall
- From the Divisions of Plastic Surgery and Health Services Research and the Department of Pharmacy Services, University of Utah; Plastic Surgery Northwest; and the Division of Plastic and Reconstructive Surgery, Stanford University
| | - Alvin Kwok
- From the Divisions of Plastic Surgery and Health Services Research and the Department of Pharmacy Services, University of Utah; Plastic Surgery Northwest; and the Division of Plastic and Reconstructive Surgery, Stanford University
| | - Isak Goodwin
- From the Divisions of Plastic Surgery and Health Services Research and the Department of Pharmacy Services, University of Utah; Plastic Surgery Northwest; and the Division of Plastic and Reconstructive Surgery, Stanford University
| | - Barbu Gociman
- From the Divisions of Plastic Surgery and Health Services Research and the Department of Pharmacy Services, University of Utah; Plastic Surgery Northwest; and the Division of Plastic and Reconstructive Surgery, Stanford University
| | - Arash Momeni
- From the Divisions of Plastic Surgery and Health Services Research and the Department of Pharmacy Services, University of Utah; Plastic Surgery Northwest; and the Division of Plastic and Reconstructive Surgery, Stanford University
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O'Connor K, Garcia Whitlock AE, Tewksbury C, Williams NN, Dumon KR. Risk factors for postdischarge venous thromboembolism among bariatric surgery patients and the evolving approach to extended thromboprophylaxis with enoxaparin. Surg Obes Relat Dis 2021; 17:1218-1225. [PMID: 33814315 DOI: 10.1016/j.soard.2021.02.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 02/09/2021] [Accepted: 02/18/2021] [Indexed: 11/18/2022]
Abstract
BACKGROUND Venous thromboembolism (VTE) is one of the most common causes of postoperative mortality following bariatric surgery. The majority of VTE events occur after discharge from the hospital. Little consensus exists regarding who should receive extended enoxaparin thromboprophylaxis or how they should be dosed, namely whether to use weight-based or BMI-stratified dosing strategies. OBJECTIVES Provide an overview of the risk factors associated with VTE in procedures among bariatric patients including the use of predictive tools to stratify risk and the various approaches to enoxaparin chemoprophylaxis in obesity. SETTING Multiple centers. METHODS A review of the literature identified studies evaluating risk factors for VTE including demographic characteristics, co-morbidities, and operative factors. The use of calculators to stratify patients by risk and approaches to extended thromboprophylaxis in obesity were evaluated as well. RESULTS VTE was associated with increased age, weight, male sex, and prior history of VTE, all frequently included in risk calculators. Outside of those major risk factors, there is little consensus about the importance of patient diagnoses. Weight-based dosing was often superior to standardized dosing in studies across disciplines in generating target anti-Xa levels however there is no consistent association of reduced risk of VTE with therapeutic anti-Xa levels. CONCLUSIONS Risk calculators may be a valuable tool for identifying patients at high-risk for VTE, but their efficacy depends on the rating algorithm and inclusion of various risk factors and is methodologically limited by prophylactic interventions. Future work should consider if biochemical factors should be included in patient stratification approaches in particular when defining the ideal chemoprophylaxis approach. Transparency and consistency in data collection and reporting is needed to better assess and inform the ideal dosing strategy to prevent VTE following bariatric surgery.
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Affiliation(s)
- Kathleen O'Connor
- Perelman School of Medicine, Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Anna E Garcia Whitlock
- Perelman School of Medicine, Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Colleen Tewksbury
- Perelman School of Medicine, Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania.
| | - Noel N Williams
- Perelman School of Medicine, Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kristoffel R Dumon
- Perelman School of Medicine, Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
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5
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Pannucci CJ, Fleming KI, Bertolaccini CB, Prazak AM, Huang LC, Pickron TB. Assessment of Anti-Factor Xa Levels of Patients Undergoing Colorectal Surgery Given Once-Daily Enoxaparin Prophylaxis: A Clinical Study Examining Enoxaparin Pharmacokinetics. JAMA Surg 2020; 154:697-704. [PMID: 31116389 DOI: 10.1001/jamasurg.2019.1165] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Importance Between 4% and 12% of patients undergoing colorectal surgery and receiving enoxaparin, 40 mg per day, have a postoperative venous thromboembolism (VTE) event. An improved understanding of why "breakthrough" VTE events occur despite guideline-compliant prophylaxis is an important patient safety question. Objective To determine the proportion of patients undergoing colorectal surgery who received adequate anticoagulation based on peak anti-factor Xa (aFXa) levels while receiving enoxaparin at 40 mg per day. Design, Setting, and Participants This prospective, nonrandomized clinical trial was conducted between February 2017 and July 2018 with 90-day follow-up at a quaternary academic medical center in the Intermountain West and included patients undergoing colorectal surgery who had surgery after receiving general anesthesia, were admitted for at least 3 days, and received enoxaparin, 40 mg once daily. Interventions All patients had aFXa levels measured after receiving enoxaparin 40 mg per day. Patients whose aFXa level was out of range entered the trial's interventional arm where real-time enoxaparin dose adjustment and repeated aFXa measurement were performed. Main Outcomes and Measures Primary outcome: in-range peak aFXa levels (goal range, 0.3-0.5 IU/mL) with enoxaparin, 40 mg per day. Secondary outcomes: (1) in-range trough aFXa levels (goal range, 0.1-0.2 IU/mL) and (2) the proportion of patients with in-range peak aFXa levels from enoxaparin, 40 mg once daily, vs the real-time enoxaparin dose adjustment protocol. Results Over 16 months, 116 patients undergoing colorectal surgery (65 women [56.0%]; 99 white individuals [85.3%], 13 Hispanic or Latino individuals [11.2%], and 4 Pacific Islander individuals [3.5%]; mean [range] age, 52.1 [18-85] years) were enrolled. Among 106 patients (91.4%) whose peak aFXa level was appropriately drawn, 72 (67.9%) received inadequate anticoagulation (aFXa < 0.3 IU/mL) with enoxaparin, 40 mg per day. Weight and peak aFXa levels were inversely correlated (r2 = 0.38). Forty-seven patients (77%) had a trough aFXa level that was not detectable (ie, most patients had no detectable level of anticoagulation for at least 12 hours per day). Real-time enoxaparin dose adjustment was effective. Patients were significantly more likely to achieve an in-range peak aFXa with real-time dose adjustment as opposed to fixed dosing alone (85.4% vs 29.2%, P < .001). Conclusions and Relevance This study supports the finding that most patients undergoing colorectal surgery receive inadequate prophylaxis from enoxaparin, 40 mg once daily. These findings may explain the high rate of "breakthrough" VTE observed in many clinical trials. Trial Registration ClinicalTrials.gov identifier: NCT02704052.
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Affiliation(s)
- Christopher J Pannucci
- Division of Plastic Surgery, University of Utah, Salt Lake City.,Division of Health Services Research, University of Utah, Salt Lake City
| | - Kory I Fleming
- Division of Plastic Surgery, University of Utah, Salt Lake City
| | | | | | - Lyen C Huang
- Division of General Surgery, University of Utah, Salt Lake City
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6
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Pannucci CJ, Fleming KI, Bertolaccini C, Moulton L, Stringham J, Barnett S, Lin J, Varghese TK. Fixed or Weight-Tiered Enoxaparin After Thoracic Surgery for Venous Thromboembolism Prevention. Ann Thorac Surg 2020; 109:1713-1721. [PMID: 32045583 DOI: 10.1016/j.athoracsur.2019.12.058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 11/19/2019] [Accepted: 12/23/2019] [Indexed: 01/27/2023]
Abstract
BACKGROUND Venous thromboembolism is an important patient safety issue in thoracic surgery patients. The optimal enoxaparin dose remains unclear. This multicenter pre/post clinical trial compared the pharmacokinetics of fixed versus weight-tiered enoxaparin, and their impact on 90-day venous thromboembolism and bleeding. METHODS Thoracic surgery patients were prospectively enrolled using a pre/post study design. Cohort 1 received enoxaparin 40 mg daily, and cohort 2 received a weight-tiered regimen: less than 70 kg received 30 mg daily; 70 kg to 89.9 kg received 40 mg once daily; and 90 kg or more received 50 mg daily. The primary study outcome was peak anti-factor Xa levels in response to fixed or weight-tiered enoxaparin. Secondary outcomes included trough anti-factor Xa, 90-day symptomatic venous thromboembolism, and 90-day clinically relevant bleeding. RESULTS One hundred thirty-one patients were prospectively enrolled, including 65 in the fixed-dose cohort and 66 in the weight-tiered cohort. No patient was lost to follow-up. Weight-tiered enoxaparin was not significantly more likely to produce adequate anticoagulation (peak anti-factor Xa 0.3 IU/mL or greater) when compared with fixed-dose enoxaparin (44.3% vs 48.2%, P = .67). Weight-tiered enoxaparin was not more likely to avoid over-anticoagulation (peak anti-factor Xa 0.5 IU/mL or greater) when compared with fixed-dose enoxaparin (3.3% vs 3.6%, P = 1.00). The groups had no significant difference in trough anti-factor Xa. Observed rates of 90-day symptomatic venous thromboembolism and clinically relevant bleeding were low (0% and 3.1%, respectively) and were not significantly different between groups. CONCLUSIONS This multicenter pre/post clinical trial did not show a pharmacokinetic advantage to weight-tiered enoxaparin, when compared with fixed-dose enoxaparin, in thoracic surgery patients. (Clinicaltrials.gov identifier: NCT03251963.).
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Affiliation(s)
| | - Kory I Fleming
- Division of Plastic Surgery, University of Utah, Salt Lake City, Utah
| | | | - Lauren Moulton
- Huntsman Cancer Hospital Intensive Care Unit, University of Utah, Salt Lake City, Utah
| | - John Stringham
- Division of Cardiothoracic Surgery, University of Utah, Salt Lake City, Utah
| | - Shari Barnett
- Section of Thoracic Surgery, University of Michigan, Ann Arbor, Michigan
| | - Jules Lin
- Section of Thoracic Surgery, University of Michigan, Ann Arbor, Michigan
| | - Thomas K Varghese
- Huntsman Cancer Hospital Intensive Care Unit, University of Utah, Salt Lake City, Utah
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7
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Venous thromboembolism chemoprophylaxis regimens in trauma and surgery patients with obesity: A systematic review. J Trauma Acute Care Surg 2019; 88:522-535. [DOI: 10.1097/ta.0000000000002538] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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8
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Gilmartin CE, Cutts BA, Ismail H. Venous thromboembolism prophylaxis of the obese postpartum patient: A cross-sectional study. Aust N Z J Obstet Gynaecol 2019; 60:376-381. [PMID: 31514236 DOI: 10.1111/ajo.13054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 08/10/2019] [Indexed: 12/23/2022]
Abstract
BACKGROUND Obesity increases risk of venous thromboembolism (VTE) in obstetric patients regardless of delivery mode and for up to six weeks postpartum. AIM This study aimed to examine postpartum pharmacological VTE prophylaxis practices for obese women at an Australian tertiary referral hospital. MATERIALS AND METHODS Medical records were retrieved for obese obstetric patients who delivered during May 2016-May 2017. Records were examined for demographic data, VTE risk factors, and LMWH (low-molecular-weight heparin) use. Due to lack of specific Australian or local guidelines, practice was evaluated using recommendations from the Royal College of Obstetricians and Gynaecologists (RCOG-UK). Patients with BMI (body mass index) <30, incomplete/unavailable medical records, and those discharged from other health services were excluded. RESULTS One hundred and eight postpartum patients (70 caesareans, 38 vaginal deliveries) with a BMI ≥ 30 kg/m2 were reviewed. Of these patients, 53 (49.1%) had a BMI ≥ 40 kg/m2 . Ninety-eight of 108 (90.7%) patients had ≥2 VTE risk factors including a BMI ≥ 30 kg/m2 . One hundred and three of 108 (95.4%) patients were indicated for postpartum VTE prophylaxis with LMWH, and 77 of 103 (74.8%) patients received it. Three of five patients meeting criteria for ≥6 weeks of LMWH thromboprophylaxis had it prescribed. Of the 72 patients whose weight exceeded 90 kg and who also received LMWH, 32 (44.4%) were prescribed a weight-adjusted dose. CONCLUSION VTE prophylaxis practices using LMWH in obese postpartum patients, including weight-adjusting doses and extended-course prescribing, appear variable. Limited literature, recommendation discrepancies, and varied awareness of recommendations may be contributing factors. Further education and research regarding this high-risk cohort are warranted.
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Affiliation(s)
- Christine E Gilmartin
- The Royal Women's Hospital Pharmacy Department, The Royal Women's Hospital, Melbourne, Victoria, Australia
| | - Briony A Cutts
- Department of Obstetrics, The Royal Women's Hospital, Melbourne, Victoria, Australia.,Department of Haematology, The Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Huda Ismail
- The Royal Women's Hospital Pharmacy Department, The Royal Women's Hospital, Melbourne, Victoria, Australia
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Yam L, Bahjri K, Geslani V, Cotton A, Hong L. Enoxaparin Thromboprophylaxis Dosing and Anti-Factor Xa Levels in Low-Weight Patients. Pharmacotherapy 2019; 39:749-755. [PMID: 31112313 DOI: 10.1002/phar.2295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Enoxaparin is a widely used anticoagulant to prevent venous thromboembolism (VTE). A fixed dose is recommended for VTE prophylaxis. However, fixed prophylactic doses of enoxaparin in low-weight patients may be close to the weight-based dosing recommended for VTE treatment. OBJECTIVE To evaluate peak anti-factor Xa (aFXa) levels in low-weight patients receiving enoxaparin for VTE prophylaxis. METHODS Retrospective cohort of adult patients weighing < 55 kg who were hospitalized at Loma Linda University Medical Center between January 2008 and February 2017. All patients received enoxaparin for VTE prophylaxis with a peak aFXa level drawn. The primary endpoint was the proportion of patients achieving peak aFXa levels within the goal range of 0.2-0.5 unit/ml. RESULTS Of 35 patients receiving enoxaparin for VTE prophylaxis with an appropriately timed peak aFXa level, 74% achieved goal peak aFXa levels and the median daily dose of enoxaparin was 30 mg. The mean weight was approximately 44 kg. No significant correlations between aFXa level and body mass index or body weight were found. CONCLUSION A lower dose of enoxaparin may be reasonable in low-weight patients for VTE prophylaxis. There appears to be no safety concerns with reduced enoxaparin dosing in low-weight patients. More robust data are needed to confirm these findings.
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Affiliation(s)
- Lily Yam
- PIH Health Hospital Downey, Downey, California
| | - Khaled Bahjri
- School of Pharmacy, Loma Linda University, Loma Linda, California
| | - Van Geslani
- School of Medicine, Loma Linda University, Loma Linda, California
| | - Adrian Cotton
- Loma Linda University Medical Center, Loma Linda, California
| | - Lisa Hong
- School of Pharmacy, Loma Linda University, Loma Linda, California
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10
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Pannucci CJ, Fleming KI, Bertolaccini C, Prazak AM, Stoddard GJ, Momeni A. Double-Blind Randomized Clinical Trial to Examine the Pharmacokinetic and Clinical Impacts of Fixed Dose versus Weight-based Enoxaparin Prophylaxis: A Methodologic Description of the FIxed or Variable Enoxaparin (FIVE) Trial. PLASTIC AND RECONSTRUCTIVE SURGERY-GLOBAL OPEN 2019; 7:e2185. [PMID: 31321183 PMCID: PMC6554177 DOI: 10.1097/gox.0000000000002185] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 01/25/2019] [Indexed: 11/29/2022]
Abstract
Venous thromboembolism is an important patient safety in plastic surgery, and multiple clinical trials in the past 10 years have provided increased understanding of the risks and benefits of venous thromboembolism prevention strategies. This paper provides an exhaustive discussion of the rationale behind and methodology for an in progress randomized double-blind clinical trial in plastic surgery inpatients, in which the 2 study arms are enoxaparin 40 mg twice daily and enoxaparin 0.5 mg/kg twice daily. The trial's primary aims are to: (1) demonstrate whether enoxaparin 0.5 mg/kg twice daily is superior to enoxaparin 40 mg twice daily for the pharmacokinetic endpoint of overanticoagulation (anti-Factor Xa > 0.4 IU/mL) and (2) demonstrate whether enoxaparin 0.5 mg/kg twice daily is not inferior to enoxaparin 40 mg twice daily for the pharmacokinetic endpoint of underanticoagulation (anti-Factor Xa < 0.2 IU/mL). The results of this trial will provide Level I evidence to help guide plastic surgeon's choice of postoperative prophylactic anticoagulation.
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Affiliation(s)
- Christopher J. Pannucci
- From the Division of Plastic Surgery, Division of Health Services Research, University of Utah, Salt Lake City, Utah
| | - Kory I. Fleming
- Division of Plastic Surgery, University of Utah, Salt Lake City, Utah
| | | | - Ann Marie Prazak
- Department of Pharmacy, University of Utah, Salt Lake City, Utah
| | - Gregory J. Stoddard
- Study Design and Biostatistics Center, University of Utah, Salt Lake City, Utah
| | - Arash Momeni
- Division of Plastic and Reconstructive Surgery, Stanford University, Palo Alto, Calif
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11
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Twice-Daily Enoxaparin among Plastic Surgery Inpatients: An Examination of Pharmacodynamics, 90-Day Venous Thromboembolism, and 90-Day Bleeding. Plast Reconstr Surg 2018; 141:1580-1590. [PMID: 29608533 DOI: 10.1097/prs.0000000000004379] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Low anti-factor Xa level, indicative of inadequate enoxaparin dosing, has a significant association with 90-day venous thromboembolism events. The authors examined the pharmacodynamics of enoxaparin 40 mg twice daily and its correlation with anti-factor Xa level, postoperative venous thromboembolism, and bleeding. METHODS Adult patients were admitted after plastic and reconstructive surgery and received enoxaparin 40 mg twice daily. Peak anti-factor Xa levels, which quantify enoxaparin's antithrombotic effect, were drawn, with a goal level of 0.2 to 0.4 IU/ml. Ninety-day symptomatic venous thromboembolism and clinically relevant bleeding were identified. RESULTS The authors enrolled 118 patients who received enoxaparin 40 mg twice daily. Of these patients, 9.6 percent had low peak anti-factor Xa levels (<0.2 IU/ml), 62.6 percent had in-range peak anti-factor Xa levels (0.2 to 0.4 IU/ml), and 27.8 percent had high anti-factor Xa levels (>0.4 IU/ml). With enoxaparin 40 mg twice daily, 90.4 percent of patients received at least adequate prophylaxis. Patient weight predicted the rapidity of enoxaparin metabolism. Zero acute 90-day venous thromboembolism occurred. Eight patients (6.8 percent) had clinically relevant 90-day bleeding: clinical consequences ranged from cessation of enoxaparin prophylaxis to transfusion to operative hematoma evacuation. CONCLUSIONS When enoxaparin 40 mg twice daily is provided, 90 percent of patients receive at least adequate venous thromboembolism prophylaxis (anti-factor Xa level >0.2 IU/ml). However, 27 percent of the overall population is overtreated (anti-factor Xa level >0.4 IU/ml). These pharmacodynamics data likely explain the low rate of 90-day acute venous thromboembolism (0 percent) and the high rate of clinically relevant bleeding (6.8 percent) observed. Future studies are needed to better optimize the risks and benefits of enoxaparin prophylaxis in plastic and reconstructive surgery patients. CLINICAL QUESTION/LEVEL OF EVIDENCE Therapeutic, IV.
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12
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Rottenstreich A, Levin G, Elchalal U, Kleinstern G, Spectre G, Ziv E, Yagel S, Kalish Y. The effect on thrombin generation and anti-Xa levels of thromboprophylaxis dose adjustment in post-cesarean obese patients - A prospective cohort study. Thromb Res 2018; 170:69-74. [DOI: 10.1016/j.thromres.2018.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/16/2018] [Accepted: 08/11/2018] [Indexed: 10/28/2022]
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13
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Weight-Based Dosing for Once-Daily Enoxaparin Cannot Provide Adequate Anticoagulation for Venous Thromboembolism Prophylaxis. Plast Reconstr Surg 2017; 140:815-822. [PMID: 28953735 DOI: 10.1097/prs.0000000000003692] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Surgeons commonly provide enoxaparin prophylaxis to high-risk patients to decrease venous thromboembolism risk. The authors' prior work demonstrated that most patients receive inadequate venous thromboembolism prophylaxis, based on anti-factor Xa level, when enoxaparin 40 mg/day is provided and that peak anti-factor Xa level correlates with weight. This study models a weight-based strategy for daily enoxaparin prophylaxis and its impact on anti-factor Xa levels. METHODS The authors enrolled plastic surgery patients who received enoxaparin 40 mg/day and had anti-factor Xa levels drawn. The enoxaparin dose of 40 mg was converted to a milligram-per-kilogram dose for each patient. Stratified analysis examined the milligram-per-kilogram dose that produced low, in-range, and high anti-factor Xa levels to identify the appropriate milligram-per-kilogram dose to optimize venous thromboembolism prevention and bleeding events. RESULTS Among 94 patients, weight-based dosing ranged from 0.28 to 0.94 mg/kg once daily. For peak and trough anti-factor Xa levels, there was nearly complete overlap for milligram-per-kilogram dosing that produced low versus in-range anti-factor Xa levels. For peak anti-factor Xa, there was nearly complete overlap for milligram-per-kilogram dosing that produced in-range versus high anti-factor Xa levels. Mean milligram-per-kilogram dose was not significantly different between patients who did or did not have postoperative venous thromboembolism (0.41 mg/kg versus 0.52 mg/kg; p = 0.085) or clinically relevant bleeding (0.48 mg/kg versus 0.51 mg/kg; p = 0.73). CONCLUSIONS Alterations in enoxaparin dose magnitude based on patient weight cannot allow a high proportion of patients to achieve appropriate anti-factor Xa levels when once-daily enoxaparin prophylaxis is provided. Future research should examine the impact of increased enoxaparin dose frequency on anti-factor Xa levels, venous thromboembolism events, and bleeding. CLINICAL QUESTION/LEVEL OF EVIDENCE Therapeutic, IV.
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14
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Review of current evidence available for guiding optimal Enoxaparin prophylactic dosing strategies in obese patients-Actual Weight-based vs Fixed. Crit Rev Oncol Hematol 2017; 113:191-194. [PMID: 28427508 DOI: 10.1016/j.critrevonc.2017.03.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 02/24/2017] [Accepted: 03/20/2017] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND The current debate over the optimal Enoxaparin prophylactic dosing strategies in obese patients centre around whether it should be based on the actual weight of the patient (i.e. weight-based), or at an artificially fixed amount, as it is the case in Australia (40mg daily). The vast majority of the evidence available today is laboratory-based, measuring serum Antifactor-Xa activities as a marker for physiological response. AIM The aim of the parent study is to compare the clinical outcomes for obese patients who received fixed doses of enoxaparin compared to those who received weight-based doses within the licensed dosage recommendations. This review was conducted to examine whether a gap in knowledge exists in relation to dosing obese patients with enoxaparin as VTE prophylaxis after hospital admission to aid in development of the parent study concept. METHOD Databases such as Medline, EBSCOhost, ProQuest were interrogated using combinations of words such as "enoxaparin", AND "dosing strategy", AND "obese/obesity" AND "prophylaxis". Only eleven out of 14 primary studies which were considered to be sufficiently similar in methodology and anticipated outcomes were reviewed and analysed. RESULTS Pooled data from the eleven studies suggested that weight-based or higher-than-fixed dosing had a 36.2% higher success rate than fixed dosing, and was more likely to achieve the desired serum Anti-Xa activity levels (52.2% and 16% respectively). The rate of failure to achieve this is significantly lower in the weight-based groups (13.3%) than in fixed-dose groups (18.5%). These eleven studies reviewed included 601 patients in total. CONCLUSION There is insufficient evidence to support or negate the current enoxaparin health outcomes in obese and very obese patients due to the lack of post-discharge follow-up from hospitals. Further research is required to compare long-term outcomes after fixed and weight-based dosing of enoxaparin. The optimal dose of enoxaparin per kilogram of body weight for prophylaxis remains to be determined.
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15
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Pariser JJ, Pearce SM, Anderson BB, Packiam VT, Prachand VN, Smith ND, Steinberg GD. Extended Duration Enoxaparin Decreases the Rate of Venous Thromboembolic Events after Radical Cystectomy Compared to Inpatient Only Subcutaneous Heparin. J Urol 2017; 197:302-307. [DOI: 10.1016/j.juro.2016.08.090] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2016] [Indexed: 01/18/2023]
Affiliation(s)
- Joseph J. Pariser
- Section of Urology, Department of Surgery, University of Chicago Pritzker School of Medicine, Chicago, Illinois
| | - Shane M. Pearce
- Section of Urology, Department of Surgery, University of Chicago Pritzker School of Medicine, Chicago, Illinois
| | - Blake B. Anderson
- Section of Urology, Department of Surgery, University of Chicago Pritzker School of Medicine, Chicago, Illinois
| | - Vignesh T. Packiam
- Section of Urology, Department of Surgery, University of Chicago Pritzker School of Medicine, Chicago, Illinois
| | - Vivek N. Prachand
- Section of General Surgery, Department of Surgery, University of Chicago Pritzker School of Medicine, Chicago, Illinois
| | - Norm D. Smith
- Section of Urology, Department of Surgery, University of Chicago Pritzker School of Medicine, Chicago, Illinois
| | - Gary D. Steinberg
- Section of Urology, Department of Surgery, University of Chicago Pritzker School of Medicine, Chicago, Illinois
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16
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Pannucci CJ, Rondina MT. Should we be following anti-factor Xa levels in patients receiving prophylactic enoxaparin perioperatively? Surgery 2016; 161:329-331. [PMID: 27712881 DOI: 10.1016/j.surg.2016.07.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 07/27/2016] [Indexed: 10/20/2022]
Affiliation(s)
- Christopher J Pannucci
- Division of Plastic Surgery, Division of Health Services Research, University of Utah, Salt Lake City, UT.
| | - Matthew T Rondina
- Division of General Internal Medicine, Department of Medicine, University of Utah Molecular Medicine Program, Salt Lake City, UT; George E. Wahlen VAMC GRECC, Salt Lake City, UT
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17
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Utility of anti-factor Xa monitoring in surgical patients receiving prophylactic doses of enoxaparin for venous thromboembolism prophylaxis. Am J Surg 2016; 213:1143-1152. [PMID: 27692434 DOI: 10.1016/j.amjsurg.2016.08.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 07/25/2016] [Accepted: 08/14/2016] [Indexed: 11/21/2022]
Abstract
BACKGROUND Between 2% and 10% of the highest risk surgery, patients have a "breakthrough" venous thromboembolism (VTE) event despite receipt of chemoprophylaxis. The goals of this review are to summarize how patient-level factors may predict enoxaparin metabolism and how alterations in enoxaparin dose magnitude and frequency affect both anti-factor Xa (aFXa) levels and downstream VTE events. DATA SOURCES Relevant articles were identified on PubMed. Fixed-dose prophylaxis provides inadequate enoxaparin prophylaxis for most surgical patients based on anti-factor Xa levels. Inadequate enoxaparin dosing has been correlated with both asymptomatic and symptomatic VTE events. Patient-level factors such as gross weight and extent of injury predict enoxaparin metabolism. Weight-based or weight-tiered dosing regimens-and real-time dose adjustment based on anti-factor Xa levels-allow an increased proportion of patients to have in-range anti-factor Xa levels. CONCLUSIONS Inadequate enoxaparin dosing may explain why some patients have VTE despite enoxaparin prophylaxis. Ongoing research in the utility of weight-based or anti-factor Xa level driven enoxaparin dosing and dose adjustment is reasonable.
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Discussion: Evidence for Extending the Duration of Chemoprophylaxis following Free Flap Harvest from the Lower Extremity: Prospective Screening for Deep Venous Thrombosis. Plast Reconstr Surg 2016; 138:509-512. [PMID: 27064220 DOI: 10.1097/prs.0000000000002400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Stephenson ML, Serra AE, Neeper JM, Caballero DC, McNulty J. A randomized controlled trial of differing doses of postcesarean enoxaparin thromboprophylaxis in obese women. J Perinatol 2016; 36:95-9. [PMID: 26658126 DOI: 10.1038/jp.2015.130] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 09/07/2015] [Accepted: 09/09/2015] [Indexed: 01/16/2023]
Abstract
OBJECTIVE To compare two enoxaparin dosing strategies at achieving prophylactic anti-Xa levels in women with a body mass index (BMI) ⩾35 (kg m(-2)) postcesarean delivery. STUDY DESIGN Women with BMI ⩾35 were randomized to receive prophylactic enoxaparin at a fixed dose of 40 mg daily or weight-based dosing of 0.5 mg kg(-1) twice daily. The primary outcome was the proportion of subjects with peak anti-Xa levels in the prophylactic range of 0.2 to 0.6 IU ml(-1). RESULT From August 2013 through February 2014, 84 demographically similar women completed the protocol. In the weight-based group, 88% (37/42) of the women reached prophylactic anti-Xa levels versus 14% (6/42) in the fixed dose group (odds ratio 44.4, 95% confidence interval 12.44, 158.48, P<0.001). No anti-Xa level exceeded 0.48 IU ml(-1). There were no venous thromboembolic or bleeding events requiring reoperation or transfusion in either group. CONCLUSION Compared with fixed dosing daily, weight-based dosing twice daily more effectively achieved prophylactic anti-Xa levels without reaching the therapeutic range.
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Affiliation(s)
- M L Stephenson
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of California Irvine Medical Center, Orange, CA, USA.,Department of Obstetrics and Gynecology, Memorial Care Center for Women at Miller Children's Hospital, Long Beach Memorial Medical Center, Long Beach, CA, USA
| | - A E Serra
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of California Irvine Medical Center, Orange, CA, USA.,Department of Obstetrics and Gynecology, Memorial Care Center for Women at Miller Children's Hospital, Long Beach Memorial Medical Center, Long Beach, CA, USA
| | - J M Neeper
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of California Irvine Medical Center, Orange, CA, USA.,Department of Obstetrics and Gynecology, Memorial Care Center for Women at Miller Children's Hospital, Long Beach Memorial Medical Center, Long Beach, CA, USA
| | - D C Caballero
- Department of Obstetrics and Gynecology, Memorial Care Center for Women at Miller Children's Hospital, Long Beach Memorial Medical Center, Long Beach, CA, USA
| | - J McNulty
- Department of Obstetrics and Gynecology, Memorial Care Center for Women at Miller Children's Hospital, Long Beach Memorial Medical Center, Long Beach, CA, USA
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Abstract
OBJECTIVE To compare the adequacy of venous thromboembolism prophylaxis based on anti-Xa concentrations between weight-based enoxaparin dosing and body mass index (BMI)-stratified dosing in morbidly obese women after cesarean delivery. METHODS A prospective sequential cohort study of women with BMIs of 40 or greater who underwent cesarean delivery was conducted. Participants received either weight-based or BMI-stratified enoxaparin dosing to prevent venous thromboembolism formation. The weight-based regimen was 0.5 mg/kg of enoxaparin every 12 hours. In the BMI-stratified regimen, women with BMIs of 40-59.9 received 40 mg enoxaparin every 12 hours and women with BMIs of 60 or greater received 60 mg every 12 hours. The primary outcome was an anti-Xa concentration in the adequate thromboprophylaxis range (0.2-0.6 international units/mL). Secondary outcomes included enoxaparin dosage, timing of dosing and anti-Xa concentration, estimated surgical blood loss, postoperative changes in hemoglobin and platelets, wound hematoma, and adverse reactions to enoxaparin. Univariate analysis was used to compare dosing regimens. RESULTS Forty-two morbidly obese women received weight-based enoxaparin, and 43 received BMI-stratified dosing. Anti-Xa concentrations were significantly higher in the weight-based group compared with the BMI-stratified group (0.29±0.08 international units/mL compared with 0.17±0.07 international units/mL, P<.001). Thirty-six participants (86%) on weight-based dosing had anti-Xa concentrations within the prophylactic range compared with 11 (26%) on BMI-stratified dosing (P<.001). No participant had an anti-Xa concentration of 0.6 international units/mL or greater, the therapeutic threshold for venous thromboembolism prophylaxis. CONCLUSION In morbidly obese women after cesarean delivery, weight-based dosing of enoxaparin for venous thromboembolism prophylaxis is significantly more effective than BMI-stratified dosing in achieving adequate anti-Xa concentrations. LEVEL OF EVIDENCE II.
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