Safety and efficacy of thromboprophylaxis using enoxaparin sodium after cesarean section: A multi-center study in Japan

Estimating the value of future research into thromboprophylaxis for women during pregnancy and after delivery: a value of information analysis

BACKGROUND

Risk assessment models (RAMs) are used to select women at increased risk of venous thromboembolism (VTE) during pregnancy and the puerperium for thromboprophylaxis.

OBJECTIVES

To estimate the value of potential future studies that would reduce the decision uncertainty associated with offering thromboprophylaxis according to available RAMs in the following groups: high-risk antepartum women (eg, prior VTE), unselected postpartum women, and postpartum women with risk factors (obesity or cesarean delivery).

METHODS

A decision-analytic model was developed to simulate clinical outcomes, lifetime costs, and quality-adjusted life-years for different thromboprophylaxis strategies, including thromboprophylaxis for all, thromboprophylaxis for none, and RAM-based thromboprophylaxis. The expected value of perfect information analysis was used to determine which factors are associated with high decision uncertainty. The value of future research studies was estimated using expected value of sample information analysis. Costs were assessed from a health and social services perspective.

RESULTS

The expected value of perfect information analysis identified high decision uncertainty for high-risk antepartum women (£21.8 million) and obese postpartum women (£13.4 million), which was largely attributable to uncertainty regarding the effectiveness of thromboprophylaxis in reducing VTE. A randomized controlled trial of thromboprophylaxis compared with none in obese postpartum women is likely to have substantial value (£2.8 million; 300 participants per arm). A trial in women with previous VTE would have higher value but would be less acceptable.

CONCLUSION

Future research should focus on estimating the effectiveness of thromboprophylaxis in obese postpartum women with additional risk factors who have not had a previous VTE.

Thromboprophylaxis during pregnancy and the puerperium: a systematic review and economic evaluation to estimate the value of future research

Background

Pharmacological prophylaxis to prevent venous thromboembolism is currently recommended for women assessed as being at high risk of venous thromboembolism during pregnancy or in the 6 weeks after delivery (the puerperium). The decision to provide thromboprophylaxis involves weighing the benefits, harms and costs, which vary according to the individual's venous thromboembolism risk. It is unclear whether the United Kingdom's current risk stratification approach could be improved by further research.

Objectives

To quantify the current decision uncertainty associated with selecting women who are pregnant or in the puerperium for thromboprophylaxis and to estimate the value of one or more potential future studies that would reduce that uncertainty, while being feasible and acceptable to patients and clinicians.

Methods

A decision-analytic model was developed which was informed by a systematic review of risk assessment models to predict venous thromboembolism in women who are pregnant or in the puerperium. Expected value of perfect information analysis was used to determine which factors are associated with high decision uncertainty and should be the target of future research. To find out whether future studies would be acceptable and feasible, we held workshops with women who have experienced a blood clot or have been offered blood-thinning drugs and surveyed healthcare professionals. Expected value of sample information analysis was used to estimate the value of potential future research studies.

Results

The systematic review included 17 studies, comprising 19 unique externally validated risk assessment models and 1 internally validated model. Estimates of sensitivity and specificity were highly variable ranging from 0% to 100% and 5% to 100%, respectively. Most studies had unclear or high risk of bias and applicability concerns. The decision analysis found that there is substantial decision uncertainty regarding the use of risk assessment models to select high-risk women for antepartum prophylaxis and obese postpartum women for postpartum prophylaxis. The main source of decision uncertainty was uncertainty around the effectiveness of thromboprophylaxis for preventing venous thromboembolism in women who are pregnant or in the puerperium. We found that a randomised controlled trial of thromboprophylaxis in obese postpartum women is likely to have substantial value and is more likely to be acceptable and feasible than a trial recruiting women who have had a previous venous thromboembolism. In unselected postpartum women and women following caesarean section, the poor performance of risk assessment models meant that offering prophylaxis based on these models had less favourable cost effectiveness with lower decision uncertainty.

Limitations

The performance of the risk assessment model for obese postpartum women has not been externally validated.

Conclusions

Future research should focus on estimating the efficacy of pharmacological thromboprophylaxis in pregnancy and the puerperium, and clinical trials would be more acceptable in women who have not had a previous venous thromboembolism.

Study registration

This study is registered as PROSPERO CRD42020221094.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR131021) and is published in full in Health Technology Assessment; Vol. 28, No. 9. See the NIHR Funding and Awards website for further award information.

Safety and effectiveness of fondaparinux as a postpartum thromboprophylaxis during puerperium among muslim women: A single centre prospective study

Background: Venous thromboembolism (VTE) remains one of the leading causes of maternal morbidity and mortality, with postpartum period carrying the greatest risk. Perinatal thromboprophylaxis is often administered based on risk-factor assessment. Low molecular weight heparin has a proven safety profile in the obstetrics population, however, its porcine-derived content may lead to reduced uptake amongst certain religious groups. We aimed to evaluate the safety of fondaparinux as an alternative postpartum thromboprophylaxis.

Methods: We conducted a prospective, single arm, open label study from September 2017 until March 2018. Women who fulfilled the criteria for post natal thromboprophylaxis based on the 2015 RCOG guidelines were recruited. Each patient received subcutaneous injection of Fondaparinux, 2.5 mg daily for 10 days. A telephone interview was conducted on day 10 post delivery. Each woman was subsequently reviewed in the outpatient clinic 6 weeks postpartum. The primary outcome measure was occurrence of pulmonary embolism or deep vein thrombosis suggestive by clinical symptoms and assessment. Secondary outcome measures were allergic reaction and bleeding tendency such as secondary post-partum haemorrhage, spinal site bleeding and wound haematoma. Allergic reaction and bleeding tendency in neonates were also recorded.

Results: Sixty women were included in the analysis. There were no VTE cases amongst our cohort. No major bleeding was recorded. Two patients (3.3%) had wound haematoma, one of which occurred 3 weeks post delivery. No adverse effect in neonates was noted.

Conclusion: Fondaparinux is a safe alternative thromboprophylaxis for postpartum women.

D-dimer level significance for deep vein thrombosis screening in the third trimester: a retrospective study

Background

Venous thromboembolism often develops after surgery and childbirth, resulting in death in some cases. Although early deep vein thrombosis (DVT) detection can predict pulmonary thromboembolism, there is no early screening method for DVT in pregnant women. Lack of consensus regarding significance or setting and cut-off value interpretation of D-dimer levels further impedes venous thromboembolism screening in pregnant women.

This study aimed to examine the utility of third-trimester serum D-dimer levels as a screening test for DVT during pregnancy and to determine the frequency of asymptomatic DVT using lower-limb compression ultrasonography.

Methods

This single-center retrospective study included 497 pregnant women who underwent elective cesarean section at term in our hospital between January 2013 and December 2019. Serum D-dimer levels were preoperatively measured at 32–37 weeks’ gestation. The presence or absence of DVT in patients with serum D-dimer levels ≥ 3.0 µg/ml, the cut-off value, was examined using compression ultrasonography. In all patients, the presence or absence of clinical venous thrombosis (symptoms such as lower-limb pain, swelling, and heat sensation) was examined within 4 postoperative weeks.

The Royal College of Obstetricians and Gynecologists Guideline 2015 was referred to determine risk factors for the onset of venous thrombosis during pregnancy. Among those, we examined the risk factors for DVT that result in high D-dimer levels during pregnancy.

Results

The median age and body mass index were 35 (20–47) years and 21.2 (16.4–41.1) kg/m², respectively. Further, the median gestational age and D-dimer levels were 37 weeks and 2.1 (0.2–16.0) µg/ml, respectively. Compression ultrasonography was performed on 135 (26.5%) patients with a D-dimer level ≥ 3.0 µg/ml, with none of the patients showing DVT. All patients were followed up for 4 postoperative weeks, with none presenting with venous thromboembolism. Multivariate analysis showed that hypertensive disorders of pregnancy are an independent risk factor for venous thromboembolism that causes high D-dimer levels (odds ratio: 2.48, 95% confidence interval: 1.05–6.50, P = 0.04).

Conclusion

There may be low utility in screening for DVT using D-dimer levels in the third trimester. Further, prepartum asymptomatic DVT has a low frequency, indicating the low utility of compression ultrasonography.

Trial registration

Institutional Review Board of Tottori University Hospital (IRB no. 20A149).

Changes in serum D-dimer level and effect of enoxaparin sodium after a cesarean section: a retrospective study

Background: Pregnancy increases the risk of venous thromboembolism (VTE). During pregnancy and a post-cesarean section, an increase in D-dimer levels can be observed. However, to date, the usefulness of the D-dimer level measurement for thrombosis in pregnant women has not been determined.Objects: We aimed to evaluate the changes in D-dimer levels after a cesarean section, the risk factors of high D-dimer levels, and enoxaparin sodium's preventive effects on VTE.Methods: This retrospective study enrolled 160 pregnant women who underwent a cesarean section. D-dimer levels were measured on postoperative day (POD)1 and POD6. If on POD1, the D-dimer levels were ≥10 µg/mL, enoxaparin sodium was administered until POD7. Regardless of enoxaparin administration, when the D-dimer levels on POD6 were ≥10 µg/mL, lower-limb venous ultrasonography was performed. After a cesarean section, patients were screened for the following: factors causing high D-dimer levels, incidence of deep vein thrombosis (DVT), and need for enoxaparin.Results: The median D-dimer levels on POD1 and POD6 were 7.5 µg/mL (1.1-34.1) and 4.2 µg/mL (0.02-31.4), respectively. Enoxaparin sodium was administered to 56 patients (35%). The D-dimer levels on POD6 decreased more significantly than on POD1. The median D-dimer levels in the enoxaparin administration group significantly dropped from 14.3 (POD1) to 3.9 (POD6) (p<.001). The D-dimer levels on POD1 were higher in patients aged ≥35 years and with a hospitalization history of threatened preterm labor. In addition, on POD6, patients aged ≥35 years and with a high body mass index had high D-levels. Following a multivariate analysis, the elderly represent an independent factor for high D-levels. DVT was not observed.Conclusion: When the D-dimer levels on POD1 after a cesarean section are ≥10 µg/mL, enoxaparin reduces D-dimer levels six days after cesarean section. Moreover, patients aged ≥35 years represent an independent factor for high D-levels. These findings should be validated by further studies.

Knowledge, Awareness and Risk of Occurrence of Venous Thromboembolism of Perinatal Women

PURPOSE

The purpose of this study is to identify knowledge, awareness, and risk of occurrence of venous thromboembolism among pregnant women.

METHODS

Subjects were 106 pregnant women treated as inpatients and outpatients at a women's health hospital in a metropolitan city February 19-March 22, 2018. Instruments consisted of questionnaires that included knowledge, awareness, and risk of occurrence of venous thromboembolism queries. Collected data were analyzed by t-test, one-way analysis of variance, Mann-Whitney U test and Kruskal-Wallis test.

RESULTS

Mean score of subjects' knowledge of venous thromboembolism was 4.47 (0-15), mean score of subjects' awareness of venous thromboembolism was 66.98 (25-100), and mean score of subjects' risk factor of venous thromboembolism was 0.98 (0-44). CONCLUSIONS: Pregnant women's level of knowledge and awareness of prevention and risk factors on venous thromboembolism, is significantly low. To raise their awareness of risk symptoms and prevent occurrence of the disease, it is essential for nurses as well as medical staffs to: 1) provide an educational program on venous thromboembolism for patients; 2) assess and monitor pregnant women with a risk factor of venous thromboembolism; and 3) implement proper prophylaxis for patients.

The efficacy and safety of pharmacologic thromboprophylaxis following caesarean section: A systematic review and meta-analysis

OBJECTIVE

Our purpose is to evaluate the efficacy and safety of pharmacologic thromboprophylaxis following caesarean section (CS).

METHODS

We searched PubMed, Embase, and the Cochrane Library. Then the systematic review was performed by analysing studies that met the eligibility criteria.

RESULTS

Seven studies with 1243 participants were included, including 6 RCTs and 1 prospective cohort. Results from the meta-analysis showed that low molecular weight heparin (LMWH) was associated with no obvious decrease in the risk of thrombus compared with UHF and negative control. However, LMWH was observed to be associated with a definite increase in the risk of bleeding or haematomas in comparison to negative control (RR: 8.47, CI: 1.52-47.11).

CONCLUSION

According to current evidences, the efficacy of pharmacologic thromboprophylaxis which increases the risk of bleeding or hematomas remains controversial.

Protocol for laparoscopic cholecystectomy: Is it rocket science?

Laparoscopic cholecystectomy (LC) does not require advanced techniques, and its performance has therefore rapidly spread worldwide. However, the rate of biliary injuries has not decreased. The concept of the critical view of safety (CVS) was first documented two decades ago. Unexpected injuries are principally due to misidentification of human factors. The surgeon’s assumption is a major cause of misidentification, and a high level of experience alone is not sufficient for successful LC. We herein describe tips and pitfalls of LC in detail and discuss various technical considerations. Finally, based on a review of important papers and our own experience, we summarize the following mandatory protocol for safe LC: (1) consideration that a high level of experience alone is not enough; (2) recognition of the plateau involving the common hepatic duct and hepatic hilum; (3) blunt dissection until CVS exposure; (4) Calot’s triangle clearance in the overhead view; (5) Calot’s triangle clearance in the view from underneath; (6) dissection of the posterior right side of Calot’s triangle; (7) removal of the gallbladder body; and (8) positive CVS exposure. We believe that adherence to this protocol will ensure successful and beneficial LC worldwide, even in patients with inflammatory changes and rare anatomies.