Obstetric venous thromboembolism prophylaxis, risk factors and outcomes

Venous Thromboembolism Prophylaxis Should Be Recommended for Antepartum Admissions and Cesarean Delivery if Age and Body Mass Index are Greater Than 35

OBJECTIVE

 Venous thromboembolism (VTE) is a major cause of maternal morbidity and mortality. Current expanded treatment recommendations result in the inclusion of a large percentage of the obstetric population, which has limited their adoption. The purpose of this study was to identify a population at high risk for VTE, with minimal impact on the number of patients that would qualify for expanded treatment.

STUDY DESIGN

 We performed a retrospective analysis of a large obstetric population. International Classification of Diseases, 10th Revsion (ICD-10) codes for VTE were used to identify patients presenting for obstetric or postpartum (PP) care from January 2016 to March 2018. The review focused on high-risk factors (history of VTE or high-risk thrombophilia), antepartum hospital admissions that were >72 hours in the previous 30 days, use of sequential compression devices, body mass index (BMI; kg/m2), age, and mode of delivery. Pharmacologic treatment efficacy was set at 90, 75, or 50%.

RESULTS

 During the 27-month review period, there were 120,235 deliveries and 93 had a VTE event in the index pregnancy or within 4 weeks PP (7.7/10,000 births). A history of VTE or high-risk thrombophilia was seen in 25.8% of cases. Antepartum admission was noted in 40.9%, and the combination of cesarean delivery (CD) with age and BMI ≥35 (Age + BMI + CD) was noted in 17.3% of PP cases. Targeting these latter two groups for VTE prophylaxis with a 75% efficacy suggests that 34% of the VTE events would likely have been prevented while increasing the total population treated by approximately 2%.

CONCLUSION

 Expanding pharmacologic prophylactical coverage to include an antepartum admission of >72 hours and those with Age + BMI + CD would result in about a one-third reduction in total VTE events with about 2% requiring treatment. These data support some of the suggested recommendations for expanded pharmacological deep venous thrombosis prophylaxis.

KEY POINTS

· CD, and BMI and age >35 are high-risk factors for VTE.. · Antepartum admission >72 hours is a high-risk factor for VTE.. · Targeting antepartum admissions, CD, and BMI and age >35 would reduce VTE events by about 33%..

Maternal mortality in the United States: are the high and rising rates due to changes in obstetrical factors, maternal medical conditions, or maternal mortality surveillance?

BACKGROUND

National Vital Statistics System reports show that maternal mortality rates in the United States have nearly doubled, from 17.4 in 2018 to 32.9 per 100,000 live births in 2021. However, these high and rising rates could reflect issues unrelated to obstetrical factors, such as changes in maternal medical conditions or maternal mortality surveillance (eg, due to introduction of the pregnancy checkbox).

OBJECTIVE

This study aimed to assess if the high and rising rates of maternal mortality in the United States reflect changes in obstetrical factors, maternal medical conditions, or maternal mortality surveillance.

STUDY DESIGN

The study was based on all deaths in the United States from 1999 to 2021. Maternal deaths were identified using the following 2 approaches: (1) per National Vital Statistics System methodology, as deaths in pregnancy or in the postpartum period, including deaths identified solely because of a positive pregnancy checkbox, and (2) under an alternative formulation, as deaths in pregnancy or in the postpartum period, with at least 1 mention of pregnancy among the multiple causes of death on the death certificate. The frequencies of major cause-of-death categories among deaths of female patients aged 15 to 44 years, maternal deaths, deaths due to obstetrical causes (ie, direct obstetrical deaths), and deaths due to maternal medical conditions aggravated by pregnancy or its management (ie, indirect obstetrical deaths) were quantified.

RESULTS

Maternal deaths, per National Vital Statistics System methodology, increased by 144% (95% confidence interval, 130-159) from 9.65 in 1999-2002 (n=1550) to 23.6 per 100,000 live births in 2018-2021 (n=3489), with increases occurring among all race and ethnicity groups. Direct obstetrical deaths increased from 8.41 in 1999-2002 to 14.1 per 100,000 live births in 2018-2021, whereas indirect obstetrical deaths increased from 1.24 to 9.41 per 100,000 live births: 38% of direct obstetrical deaths and 87% of indirect obstetrical deaths in 2018-2021 were identified because of a positive pregnancy checkbox. The pregnancy checkbox was associated with increases in less specific and incidental causes of death. For example, maternal deaths with malignant neoplasms listed as a multiple cause of death increased 46-fold from 0.03 in 1999-2002 to 1.42 per 100,000 live births in 2018-2021. Under the alternative formulation, the maternal mortality rate was 10.2 in 1999-2002 and 10.4 per 100,000 live births in 2018-2021; deaths from direct obstetrical causes decreased from 7.05 to 5.82 per 100,000 live births. Deaths due to preeclampsia, eclampsia, postpartum hemorrhage, puerperal sepsis, venous complications, and embolism decreased, whereas deaths due to adherent placenta, renal and unspecified causes, cardiomyopathy, and preexisting hypertension increased. Maternal mortality increased among non-Hispanic White women and decreased among non-Hispanic Black and Hispanic women. However, rates were disproportionately higher among non-Hispanic Black women, with large disparities evident in several causes of death (eg, cardiomyopathy).

CONCLUSION

The high and rising rates of maternal mortality in the United States are a consequence of changes in maternal mortality surveillance, with reliance on the pregnancy checkbox leading to an increase in misclassified maternal deaths. Identifying maternal deaths by requiring mention of pregnancy among the multiple causes of death shows lower, stable maternal mortality rates and declines in maternal deaths from direct obstetrical causes.

Is early bilateral compression ultrasonography and D-dimer monitoring appropriately for prophylaxis and diagnosis of deep venous thrombosis after cesarean section women: a single-center observation study of Chinese Han population

BACKGROUND

Venous thromboembolism (VTE) is most prevalent among parturients following a cesarean section (CS). The objective of this study was to assess the practical utility of bilateral compression ultrasonography (CUS) of the lower limbs, coupled with D-dimer monitoring, in the early diagnosis of VTE within the Han Chinese population.

METHODS

Our prospective observational study included 742 women who underwent CUS and D-dimer testing on the first day post-CS. Subsequently, telephone or outpatient follow-ups were conducted until 42 days postpartum. States of hypercoagulation and thrombosis, as indicated by CUS, were classified as CUS abnormal. A D-dimer level ≥ 3 mg/l was considered the D-dimer warning value. Early ambulation and mechanical prophylaxis were universally recommended for all parturients post-CS. A sequential diagnostic strategy, based on the 2015 RCOG VTE risk-assessment tool, was employed. Therapeutic doses of low-molecular-weight heparin (LMWH) were administered for the treatment of thromboembolic disease. Prophylactic doses of LMWH were given for VTE prophylaxis in parturients with hypercoagulative status accompanied by D-dimer levels ≥ 3 mg/l. All high-risk women (RCOG score ≥ 4 points) were additionally treated with preventive LMWH. Statistical analyses were conducted using the R statistical software, with a two-sided P value < 0.05 considered statistically significant.

RESULTS

Fifteen cases of VTE and 727 instances without VTE were observed. The overall VTE rate post-CS was 2.02% (15/742), with 66.7% (10/15) being asymptomatic. Eleven patients received a VTE diagnosis on the first postpartum day. Among the 41 parturients exhibiting hypercoagulation ultrasound findings and D-dimer levels ≥ 3 mg/l, despite receiving pharmacological VTE prophylaxis with LMWH, 4.88% (2/41) in the high-risk group were eventually diagnosed with VTE. A total of 30.86% (229/742) exhibited normal ultrasound findings and D-dimer levels < 3 mg/l on the first day post-CS, with no VTE occurrences in the postpartum follow-up. According to RCOG's recommendation, 78.03% (579/742) of cesarean delivery women should receive prophylactic anticoagulation, while only 20.62% (153/742) met our criterion for prophylactic anticoagulation.

CONCLUSION

The strategy of timely routine bilateral CUS and D-dimer monitoring is conducive to the early diagnosis and treatment of VTE, significantly reducing the use of LMWH in the Chinese Han population.

Strategies for the prevention of maternal death from venous thromboembolism clinical recommendations based on current literature

Venous thromboembolism (VTE) is one of the leading causes of direct maternal deaths. It has been estimated that approximately 50% of these deaths are potentially preventable. The UK Confidential Enquiries into Maternal Deaths and the National Partnership for Maternal Safety have proposed strategies for the prevention of maternal deaths from VTE based on current guideline recommendations. The main strategies include: - Early recognition and comprehensive assessment of risk factors for VTE at different times from the beginning of pregnancy until patient's discharge from hospital. - Appropriate risk stratification using standardized VTE risk assessment tools (e.g. the Royal College Scoring System). - Risk-based antenatal and postnatal heparin thromboprophylaxis adjusting the heparin dosage and the duration of prophylaxis to the individual patient's risk. - Adequate management of heparin prophylaxis before and after delivery. - Preference of universal rather than selective post-cesarean heparin thromboprophylaxis and application of perioperative mechanical prophylaxis. - Avoidance of gaps in the postpartum prescription of heparin. - Good communication and cooperation between primary and secondary care including community midwifery staff in the postpartum period. - Immediate intravenous administration of (unfractionated) heparin, if pulmonary embolism is suspected. - Critical analysis of all thromboembolic events, particularly in association with maternal death to learn from failures and to realize, if and where improvement is needed. Adequate pharmacological thromboprophylaxis has the potential to reduce the risk of VTE by 60-70% in pregnant women at increased risk.