Continued part 1, part 2 of ebook Consults in obstetric anesthesiology provide readers with content about: inherited thrombophilias; insulin pump; intracranial hypertension; intracranial mass lesions; Jehovah’s witnesses; Kawasaki disease; Klippel-Trenaunay syndrome; left ventricular assist devices (LVAD);... Please refer to the part 2 of ebook for details!
Inherited Thrombophilias 89 James P R. Brown and Joanne Douglas Background: Epidemiology and Pathophysiology Presentation Parturients with inherited thrombophilias may present in several ways Women may present after investigation for a previous personal history of arterial or venous thromboembolism (VTE) Parturients may also be diagnosed after screening following a confirmed family history of thrombophilia (Please see Fig. 89.1 for a depiction of the coagulation cascade.) Incidence VTE is a major cause of pregnancy mortality and morbidity, affecting 0.5–3 per 1000 pregnancies [1] The rate of VTE is increased six-fold in pregnancy compared with the nonpregnant state, and inherited thrombophilias are responsible for up to 50% of VTEs occurring in pregnancy [2] More VTEs occur in the left leg (the right iliac artery causes mechanical compression of the left iliac vein) [3] In parturients with a previous personal history of VTE, the risk for recurrence during pregnancy is as much as 12% [1] J P R Brown, MBChB, MRCP, FRCA, MD, FRCPC (*) UBC Department of Anesthesiology, Pharmacology and Therapeutics, BC Women’s Hospital, Vancouver, BC, Canada Department of Anesthesia, BC Women’s Hospital, Vancouver, BC, Canada e-mail: james.brown@cw.bc.ca J Douglas, CM, MD, FRCPC UBC Department of Anesthesiology, Pharmacology and Therapeutics, BC Women’s Hospital, Vancouver, BC, Canada e-mail: jdouglas@cw.bc.ca Genes associated with an increased risk of VTE are carried by 15% of the Caucasian population [2] Factor V Leiden is the most common inherited thrombophilia Interaction with Pregnancy Effects of Pregnancy on Disorders By term gestation, the normal hematological response to pregnancy is to increase most coagulation factors and to decrease anticoagulant and fibrinolytic activity This creates a prothrombotic environment, which evolutionarily protects against postpartum hemorrhage (PPH) (Please see Table 89.1.) Because of the hypercoagulable state, inherited thrombophilias may present for the first time during pregnancy (Please see Table 89.2.) In addition to the hypercoagulability of normal pregnancy and inherited thrombophilias, there are additional risk factors for VTE that may be present These include: (a) Venous congestion of lower limbs (gravid uterus) (b) Bed rest for obstetric disorders (c) Morbid obesity (d) Cesarean delivery (e) Chorioamnionitis (f) Advanced maternal age (g) Acquired thrombophilias, e.g., antiphospholipid syndrome and nephrotic syndrome Effects of Disorder on Pregnancy Inherited thrombophilias are probably associated with an increased incidence of recurrent pregnancy loss, preeclampsia, and placental abruption © Springer International Publishing AG, part of Springer Nature 2018 S K W Mankowitz (ed.), Consults in Obstetric Anesthesiology, https://doi.org/10.1007/978-3-319-59680-8_89 315 316 J P R Brown and J Douglas Fig 89.1 Traditional coagulation cascade F Factor, PCC prothrombin complex concentrate, r recombinant, a activated, TF tissue factor FXIIa FXII PCC rFVIIa Intrinsic pathway Extrinsic pathway FXIa FXI TF FIX Cryoprecipitate FVII FVIIa FIXa VIIIa PCC FX FXa FX Va Final common pathway Prothrombin (FII) Thrombin Fiberinogen (FI) Fiberin Fiberin Clot Cryoprecipitate Table 89.1 Changes in blood components at term with normal pregnancy, compared to baseline Parameter FV (FV Leiden) Antithrombin PCa PS Prothrombin (FII) Changes at term gestation → → → ↓ (unbound) → Abbreviations: F factor, P protein a Although levels of protein C are unchanged, normal pregnancy is a state of relative resistance to activation of protein C, a result of decreased availability of protein S and increased factor VIII levels [4] Neonatal and Fetal Considerations Inherited thrombophilias are associated with: (a) Intrauterine growth restriction (b) Intrauterine fetal death (c) Ischemic strokes in neonates peripartum (neonatal seizures, hemiparesis, cerebral palsy) Management: Medical and Anesthetic General Principles An assessment for inherited thrombophilias should be performed prior to pregnancy when possible Where possible there should be an antenatal multidisciplinary (obstetric, anesthetic, hematology) meeting and plan for management FXIIIa Management should be tailored to the specific patient, according to individual risk stratification of likelihood of VTE during pregnancy It is important that parturients are informed of signs and symptoms of VTE and encouraged to present urgently for medical assessment should they occur There should be an agreed plan for management of anticoagulation peripartum, balancing individual risk of VTE with risk of PPH and allowing the opportunity for neuraxial analgesia or anesthesia The risks and benefits of analgesic and anesthetic options should be discussed with the patient as part of the process of informed consent On arrival to the labor suite, a complete blood count (CBC), coagulation studies as indicated, and a type and screen should be ordered Adequate intravenous access should be obtained In addition to any anticoagulation required, simple methods of reducing VTE should be employed, such as early mobilization, adequate hydration, and mechanical compression devices The greatest risk of VTE is in the weeks postpartum; prophylaxis needs to be extended for this period Testing and Diagnosis [1] Who should be screened? (a) Patients with a previous personal or family history of VTE should be screened When should screening happen? 89 Inherited Thrombophilias 317 Table 89.2 Risk of venous thromboembolism with specific thrombophilias in pregnancy Factor V Leiden (heterozygous) Factor V Leiden (homozygous) Prothrombin gene mutation (heterozygous) Prothrombin gene mutation (homozygous) Combined heterozygous Factor V Leiden/prothrombin Antithrombin deficiency (