Anticoagulation in pregnancy and neuraxial blocks

Venous Thromboembolism in Pregnancy: A Review of Diagnosis, Management, and Prevention

Venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism, is a leading cause of maternal morbidity and mortality worldwide. Physiological changes that occur in a normal pregnancy increase the risk for VTE by 4-5-fold in the antepartum period and 30-60-fold in the immediate postpartum period. Compressive ultrasonography is the diagnostic test of choice for deep vein thrombosis. Both ventilation/perfusion scanning and computed tomography pulmonary angiography can reliably diagnose pulmonary embolism. Anticoagulation for a minimum of 3 months, typically with low molecular weight heparin, is the treatment of choice for pregnancy-associated VTE (PA-VTE). Despite the significant societal burden and potentially devastating consequences, there is a paucity of data surrounding the prevention of PA-VTE, resulting in major variations between international guidelines. This review will summarize the current recommendations for diagnosis, management, and prevention of PA-VTE.

Literature review of spinal hematoma case reports: causes and outcomes in pediatric, obstetric, neuraxial and pain medicine cases

BACKGROUND

The risk of spinal epidural hematoma (SEH) has been described in the literature but the impact in various patient populations has not been assessed in the same study. We identified the risk factors for SEH and calculated the OR for recovery in the pediatric, adult and obstetric (OB) patients based on the degree of neurological deficit before surgery.

METHODS

Adult non-OB cases were categorized whether they were on anticoagulants or not; SEH was related to neuraxial or pain procedure; or whether there was adherence to the American Society of Regional Anesthesia (ASRA) guidelines. Eligible cases were identified through PubMed and Embase searches in the English literature from 1954 to July 2022.

RESULTS

A total of 940 cases were evaluated. In the pediatric cases, SEH was typically spontaneous, related to coagulopathy or athletic trauma. OB cases were spontaneous or related to neuraxial injections. Among adults on anticoagulant(s), SEH was mostly spontaneous with no related etiology or related to neuraxial procedure. SEH occurred despite adherence to the ASRA guidelines. Among non-OB adults not on anticoagulants, SEH was due to trauma, neuraxial injections, surgery or other causes. Neurological recovery was related to the degree of neurological deficit before surgery.

CONCLUSIONS

Our data show a preponderance of spontaneous SEH in all patient populations. SEH developed even though the ASRA guidelines were followed, especially in patients on multiple anticoagulants. Patients with less impairment prior to surgery had a higher likelihood of complete recovery, regardless of the interval between surgery and onset of symptoms.

Increased unfractionated heparin requirements with decreasing body mass index in pregnancy

BACKGROUND

Pregnant women receiving low-molecular-weight heparin for therapeutic anticoagulation are often converted to unfractionated heparin in anticipation of labor. We aim to characterize the impact of maternal body mass index on attainment of target anticoagulation during the conversion process.

METHODS

We conducted a five-year retrospective study of a pregnancy cohort converted from low-molecular-weight heparin to unfractionated heparin in the third trimester. Patient demographics, anticoagulation regimens, and clinical outcomes were extracted from the medical record. Nonparametric statistical methods were used for analysis by body mass index (<30, 30-35, and >35).

RESULTS

Thirty-one subjects were evenly distributed by body mass index (p = 0.97). Linear regression revealed an inverse correlation between patient body mass index and unfractionated heparin dose needed to achieve therapeutic anticoagulation (p = 0.04). Subjects with body mass index > 35 attained therapeutic activated partial thromboplastin time levels at 18 U (Units)/kg/h, while subjects with body mass index < 30 required 25 U/kg/h (p = 0.02).

CONCLUSION

Higher doses of unfractionated heparin are needed to achieve anticoagulation in patients with body mass index < 30 during pregnancy. This paradoxical relationship may be explained by physiologic characteristics that increase unfractionated heparin elimination, including diminished adiposity and increased renal clearance.

Recommendations for the prevention of pregnancy-associated venous thromboembolism

Pregnancy is a risk factor for venous thromboembolism (VTE), an important cause of maternal morbidity and mortality. Although there is a 4-5-fold increased risk compared to that of nonpregnant women of the same age, the absolute risk is low at no more than two episodes of VTE per 1000 pregnancies. There is uncertainty about which women require thromboprophylaxis during pregnancy or postpartum because of a lack of data from appropriate clinical trials. For this reason, recommendations for prophylaxis should be made only after explaining the available evidence to the patient and taking into account her perception of the balance of risk and benefit in thromboprophylaxis. The aim of these recommendations is to provide clinicians with practical advice to assist in decisions regarding thromboprophylaxis in women considered to be at risk of VTE during pregnancy and the postpartum. The authors are clinicians from across New Zealand and Australia representing the fields of haematology, obstetric medicine, anaesthesiology, maternal-fetal medicine and obstetrics. Authors were invited to review the relevant literature and then worked collaboratively to devise recommendations and resolve areas of controversy. The recommendations contained herein were reached by consensus and represent the opinion of the panel. The absence of randomised clinical trials in this area limits the strength of evidence that can be used, and it is acknowledged that they represent level C evidence. The panel advocates for appropriate clinical studies to be carried out in this patient population to address the inadequacy of present evidence.

Venous thromboembolism in pregnancy

In Western nations, venous thromboembolism (VTE) is an important cause of morbidity and the most common cause of maternal death during pregnancy and the puerperium. Pregnancy is a hypercoagulable state in which coagulation is activated and thrombolysis inhibited. This prothrombotic risk is compounded when hereditary and acquired thrombophilias and other prothrombotic risk factors are present. The risk of venous thrombotic events is increased fivefold during pregnancy and 60-fold in the first 3 months after delivery (postpartum period) compared with nonpregnant women. Many of the signs and symptoms of VTE overlap those of a normal pregnancy, which complicates the diagnosis. Patients with history of previous VTE should use graduated compression stockings throughout pregnancy and the puerperium, and should receive postpartum anticoagulant prophylaxis. The indications for antepartum anticoagulant prophylaxis are somewhat controversial. This article reviews the management of VTE during pregnancy and in the postpartum period.

Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy: American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines (Third Edition)

The actual incidence of neurologic dysfunction resulting from hemorrhagic complications associated with neuraxial blockade is unknown. Although the incidence cited in the literature is estimated to be less than 1 in 150,000 epidural and less than 1 in 220,000 spinal anesthetics, recent epidemiologic surveys suggest that the frequency is increasing and may be as high as 1 in 3000 in some patient populations.Overall, the risk of clinically significant bleeding increase with age,associated abnormalities of the spinal cord or vertebral column, the presence of an underlying coagulopathy, difficulty during needle placement,and an indwelling neuraxial catheter during sustained anticoagulation( particularly with standard heparin or low-molecular weight heparin). The need for prompt diagnosis and intervention to optimize neurologic outcome is also consistently reported. In response to these patient safety issues, the American Society of Regional Anesthesia and Pain Medicine (ASRA) convened its Third Consensus Conference on Regional Anesthesia and Anticoagulation. Practice guidelines or recommendations summarize evidence-based reviews. However, the rarity of spinal hematoma defies a prospective randomized study, and there is no current laboratory model. As a result,the ASRA consensus statements represent the collective experience of recognized experts in the field of neuraxial anesthesia and anticoagulation. These are based on case reports, clinical series, pharmacology,hematology, and risk factors for surgical bleeding. An understanding of the complexity of this issue is essential to patient management.

Anticoagulation with argatroban in a parturient with heparin-induced thrombocytopenia

Unfractionated heparin and low-molecular-weight heparin are currently the anticoagulants of choice for the prevention of recurrent thromboembolic disease during pregnancy. However, heparin-induced thrombocytopenia contraindicates the use of unfractionated heparin and low-molecular-weight heparin. We describe a patient who was admitted to our hospital with deep vein thrombosis at 18 weeks of gestation and who developed heparin-induced thrombocytopenia during her antenatal care. Therapeutic anticoagulation was initially achieved with argatroban, then changed to fondaparinux. During early labor, fondaparinux was discontinued and intravenous argatroban was substituted. Argatroban was discontinued during transition to active labor. After return of a normal partial thromboplastin time, combined spinal-epidural analgesia was induced for routine completion of labor and vaginal delivery. We discuss the decisions made in the maintenance of this patient's anticoagulation during the peripartum period as well as timing of her neuraxial labor analgesia.