Huma Khan MD MCH fellow August 3 rd, 2011

 Epidemiology of VTE in pregnancy  to be able to identify the causes of vte  To understand and identify the different diagnostic tools  Understand prenatal management  To be aware of the different pharmacotherapies  Identify risk factors for post natal management

AK is a 24 yr old obese AA G2P0010, who comes for an initial prenatal visit. She is very sure of her lmp which places her at about 8wk 3d GA. She states this a planned pregnancy and that she has been taking pnv’s. Pmhx: DVT in her left leg 4yrs ago, Pshx: none Meds: pnv

Fhx: DM, cHTN Shx: married, employed, no smoking, no etoh, hx of thc in college with occasional addition of other substances which she denies using once she graduated Obhx: SAB 2 yrs ago at 6 wks different partner

 VTE( DVT & PE) occurs in per 10,000 pregnancies  Postpartum 3 -7 per 10,000 deliveries  7-10 fold increase in antepartum  fold in post partum  PE leading cause of death in developing countries  current deaths from PE: per 100,000 deliveries

Venous stasis hypercoagulabil ity Vascular damage

 Virchow's triad  Venous stasis:  1 st trimester to 36wk  Progesterone induced venodilation  Right iliac artery over left iliac vein  Gravid uterus  Immobilization

 Virchow's triad  Vascular damage:  Compression at delivery  Assisted or operative delivery  Hypercoagulability:   procoagulant factors   anticoagulant activity   fibrinolytic activity  = more thrombin generation + less clot dissolution

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 black race  Heart disease  Sickle cell disease  Diabetes  Lupus  Smoking  Multiple pregnancy  Ama  Obesity ( BMI > 30)  C-section( especially emergent or after long labor)

 disorder of hemostasis predisposing to thrombotic event  Inherited  Factor V Leiden  Prothrombin G20210A  Acquired  Antiphospholipid antibody syndrome  Lupus anticoagulant

 cause 50 % of VTE in pregnancy  Occur only in 0.1% of pregnancies  Universal screening not cost effective  Screening affected in pregnancy  protein S levels fall in 2 nd trimester  Massive thrombus & nephrotic syndrome decrease antithrombin levels  Liver disease decrease protein C & S levels  Screening should be done after pregnancy and when no longer taking anticoagulants

 Complications  Early and late losses  IUGR  Placental abruption

 Difficult to differentiate from pregnancy sx’s  DVT:  Unilateral leg pain and swelling, especially left leg  ≥ 2 cm calf circumference difference  1 st trimester  Homan’s sign

Dresand et al. aafp,77: , 2008

 VCUS ( venous compression ultrasonagraphy)  Sensitivity : %  Specificity : %  Less accurate for isolated calf and iliac vein thrombosis  D-Dimer  Levels increase during pregnancy  Usually positive and hence of little use  Negative test with low clinical probability has a NPV of 99.5 % when highly sensitive assay used.  positive test sensitivity is 100% & specificity is 60% hence additional testing is needed  MRI and ct can be done in high probability pts

 Difficult to differentiate from pregnancy sx’s  PE:  Dyspnea  Chest pain  Unexplained tachycardia

Dresand et al. aafp,77: , 2008

 v/q scan  PPV when combined with high clinical pretest is 96%  Only 56% with low clinical pretest  Radiation dose : mGY  ct  In one study PPV’s in  Lobar: 97%  segmental:68%  Subsegmental: 25%  False positive rates: 30%, detected incorrectly in segmental/ subsegmental  Radiation dose: gy

AK is a 24 yr old obese AA G2P0010, who comes for an initial prenatal visit. She is very sure of her lmp which places her at about 8wk 3d GA. She states this a planned pregnancy and that she has been taking pnv’s. Pmhx: DVT in her left leg 4yrs ago, Pshx: none Fhx: DM, cHTN Meds: pnv Shx: married, employed, no smoking, no etoh, hx of thc in college with occasional addition of other substances which she denies using once she graduated Obhx: SAB 2 yrs ago at 6 wks different partner

 On further examination you find  BP: 140/85  BMI of 32  A few varicose veins on her right calf  On US she is 10wk with twin gestation

 Identify the risk factors  prenatal management  What do do during labor and delivery  Identify risk factor for post partum management

Rcog Green- top guideline 37, 2009

 prophylaxis in pregnancy Marik & Plante nejm,359: , 2008

 Therapeutic dosing in pregnancy  Vena caval filters Marik & Plante nejm,359: , 2008

LMWH  More predictable dose response  More dose independent mechanisms of clearance  Long plasma half life  Once or twice daily dosing  No lab visits  Lower risk of bleeding, HIT & fractures  Not easily reversed UFH  Dose dependent response  Clearance is dependent on renal / liver function  Half life is short and dose dependent  Multiple dosing  Labs for PLTS  High risk of bleeding and HIT  Easily reversed by protamine sulphate

 Crosses placenta  Increases miscarriage, stillbirth, embryopathy (midface hypoplasia,stippled epiphyses) if exposed in 1 st trimester  In 2 nd and 3 rd trimester causes CNS abnormalities and hemorrhage  It is compatible with breast feeding

 Switch to UFH several wks before  stop all anticoagulation with onset of labor  If planned IOL or c-section then stop 24 hrs prior to  Management varies based on prophylaxis /treatment doses

 neuroaxial anesthesia contra-indicated in spontaneous labor with full anticoagulation  Spinal anesthesia placed  12 hrs after prophylactic dose of LMWH  24 hrs after therapeutic dose of LMWH  6 hrs after UFH dose and confirmed normal activated partial-thromboplastin time  General preferred if emergent c-section  Anticipate larger blood loss

Bourjeily et al. lancet 375:500-12, 2010

 Post partum thromboprophylaxis not routinely indicated  ASA not used  Thromboprophylaxis for 6-12 wks  Warfarin can be used

 Incidence of PE higher by a factor of 2.5 to 20  Incidence of fatal PE by a factor of 10  Thromboprophylaxis highly effective in reducing the high incidence  Duration is 3-7 days for intermediate risk  Up to 6 wks for high risk.

Rcog Green- top guideline 37, 2009