Comparing Anti-XA Levels in Post-Cesarean Patients Undergoing Enoxaparin Thromboprophylaxis
| Status: | Completed |
|---|---|
| Conditions: | Obesity Weight Loss, Cardiology, Cardiology, Cardiology, Cardiology, Cardiology, Women's Studies |
| Therapuetic Areas: | Cardiology / Vascular Diseases, Endocrinology, Reproductive |
| Healthy: | No |
| Age Range: | 18 - Any |
| Updated: | 4/21/2016 |
| Start Date: | August 2013 |
| End Date: | March 2014 |
Comparing Anti-XA Levels in Post-Cesarean Patients With BMI >35 Undergoing Enoxaparin Thromboprophylaxis With Weight Based Dosing Twice Daily Versus Fixed Dose 40 Milligrams Daily
Pregnant and recently postpartum women are at significantly higher risk of developing a
blood clot in their arms or legs known as a deep venous thrombosis (DVT) and/or a blood clot
in their lungs known as a pulmonary embolism (PE) compared to their non pregnant
counterparts. It is estimated that this risk increases anywhere from 4 to 50 times higher in
pregnant versus non-pregnant women and further increases almost 11 fold in the post partum
period. This risk is almost doubled when the patient undergoes cesarean delivery. In 2011,
the American College of Obstetricians and Gynecologists (ACOG) issued updated guidelines
stating that for patients undergoing cesarean delivery with additional risk factors for clot
or thromboembolism, protective (prophylactic) treatment with low molecular weight heparin
(LMWH) a type of blood thinner should be considered. However, no specific guidelines about
which risk factors should be considered, or what medication doses should be used were
provided. The American College of Chest Physicians (ACCP) Evidence-Based Clinical Practice
Guidelines published in 2012 delineated who should be given prophylaxis based on various
risk factors, however acknowledged that the recommendations were based on weak quality
evidence.
ACOG endorses either once or twice a day dosing for high risk patients after delivery and
states that adjustments for obese women should be made on a case by case basis. However,
there are limited studies on the dosing of LMWH in specific subpopulations including post
operative patients, pregnant patients and obese patients. All of these studies have urged
further investigation of the correct dosing for these high risk subjects due to changes
associated with pregnancy and the level of medication in the blood that may put these
patients at higher risk of venous thromboembolism. Many previous studies have shown that
women in these high risk categories do not achieve protective levels of the medication
measured with a laboratory test; anti Xa level. The investigators hypothesize that due to
their dual risk, obese post-operative recently pregnant women may not be adequately
protected with the daily fixed dose and might need more frequent dosing to protect them.
The objective of this study is to assess what proportion of women achieve the desired anti
Xa level with the fixed daily dose versus twice daily weight based dosing (0.5 mg/kg).
blood clot in their arms or legs known as a deep venous thrombosis (DVT) and/or a blood clot
in their lungs known as a pulmonary embolism (PE) compared to their non pregnant
counterparts. It is estimated that this risk increases anywhere from 4 to 50 times higher in
pregnant versus non-pregnant women and further increases almost 11 fold in the post partum
period. This risk is almost doubled when the patient undergoes cesarean delivery. In 2011,
the American College of Obstetricians and Gynecologists (ACOG) issued updated guidelines
stating that for patients undergoing cesarean delivery with additional risk factors for clot
or thromboembolism, protective (prophylactic) treatment with low molecular weight heparin
(LMWH) a type of blood thinner should be considered. However, no specific guidelines about
which risk factors should be considered, or what medication doses should be used were
provided. The American College of Chest Physicians (ACCP) Evidence-Based Clinical Practice
Guidelines published in 2012 delineated who should be given prophylaxis based on various
risk factors, however acknowledged that the recommendations were based on weak quality
evidence.
ACOG endorses either once or twice a day dosing for high risk patients after delivery and
states that adjustments for obese women should be made on a case by case basis. However,
there are limited studies on the dosing of LMWH in specific subpopulations including post
operative patients, pregnant patients and obese patients. All of these studies have urged
further investigation of the correct dosing for these high risk subjects due to changes
associated with pregnancy and the level of medication in the blood that may put these
patients at higher risk of venous thromboembolism. Many previous studies have shown that
women in these high risk categories do not achieve protective levels of the medication
measured with a laboratory test; anti Xa level. The investigators hypothesize that due to
their dual risk, obese post-operative recently pregnant women may not be adequately
protected with the daily fixed dose and might need more frequent dosing to protect them.
The objective of this study is to assess what proportion of women achieve the desired anti
Xa level with the fixed daily dose versus twice daily weight based dosing (0.5 mg/kg).
This is a multi-center, prospective, randomized controlled study to compare the proportion
of patients that achieve the desired effect of LMWH (enoxaparin) thromboprophylaxis as
measured by peak anti Xa level with weight based twice daily dosing versus standard fixed
daily dosing. The investigators hypothesize that when enoxaparin is dosed by maternal weight
and administered twice daily, the anti-factor Xa level would more frequently achieve
prophylactic levels when compared to taking a fixed 40 mg of the drug daily.
Subjects will be women with a BMI > 35 who have undergone a cesarean delivery and who will
receive thromboprophylaxis with enoxaparin (Lovenox) at the judgment of their physician.
Women who are eligible and consent to participate in the study will be randomized in a 1:1
ratio to one of the following groups:
Group 1 will receive the weight based dosing (0.5mg/kg BID) enoxaparin (Lovenox®; Aventis
Pharmaceuticals) regimen Group 2 will received the fixed dose (40mg daily) enoxaparin
(Lovenox®; Aventis Pharmaceuticals) regimen.
Treatment will begin between 8 and 12 hours post operatively and this regimen will continue
until discharge from the hospital, usually on the third or fourth day after surgery. A
single peak anti Xa level will be drawn 3.5-4 hours after the third dose of medication. The
results of the anti Xa level will only be for research purposes and will not guide clinical
management.
The primary outcome for this study is to assess the peak anti-factor Xa level in the blood,
and whether or not the subject achieved the desired prophylactic level when receiving fixed
dose of enoxaparin compared with weight based dosing.
of patients that achieve the desired effect of LMWH (enoxaparin) thromboprophylaxis as
measured by peak anti Xa level with weight based twice daily dosing versus standard fixed
daily dosing. The investigators hypothesize that when enoxaparin is dosed by maternal weight
and administered twice daily, the anti-factor Xa level would more frequently achieve
prophylactic levels when compared to taking a fixed 40 mg of the drug daily.
Subjects will be women with a BMI > 35 who have undergone a cesarean delivery and who will
receive thromboprophylaxis with enoxaparin (Lovenox) at the judgment of their physician.
Women who are eligible and consent to participate in the study will be randomized in a 1:1
ratio to one of the following groups:
Group 1 will receive the weight based dosing (0.5mg/kg BID) enoxaparin (Lovenox®; Aventis
Pharmaceuticals) regimen Group 2 will received the fixed dose (40mg daily) enoxaparin
(Lovenox®; Aventis Pharmaceuticals) regimen.
Treatment will begin between 8 and 12 hours post operatively and this regimen will continue
until discharge from the hospital, usually on the third or fourth day after surgery. A
single peak anti Xa level will be drawn 3.5-4 hours after the third dose of medication. The
results of the anti Xa level will only be for research purposes and will not guide clinical
management.
The primary outcome for this study is to assess the peak anti-factor Xa level in the blood,
and whether or not the subject achieved the desired prophylactic level when receiving fixed
dose of enoxaparin compared with weight based dosing.
Inclusion Criteria:
- Women with a body mass index >35 who have undergone cesarean delivery in the last 12
hours who will receive thromboprophylaxis with enoxaparin
- Subjects who consent to the study.
Exclusion Criteria:
- Women with a previous history of deep venous thrombosis or pulmonary embolism
- Women who are currently receiving another form of low molecular weight heparin or
unfractionated heparin.
- Women who are receiving other concomitant anticoagulant medications, such as
warfarin, lepirudin, or argatroban.
- Subjects who are unable or unwilling to give informed consent.
- Women who, in the judgment of the investigators, would not be in the best interest of
the patient to participate in the study.
- Allergy to enoxaparin.
- Women with renal impairment
- Women with contraindications to Lovenox treatment such as women with active bleeding
or thrombocytopenia
We found this trial at
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Long Beach, California 90806
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