Anti Coagulation In PregnancyPresentation Transcript
Anticoagulation in Pregnancy and Neuraxial block MehtabAlamHaidry
Case Scenario 32 years old patient with a history of mitral valve replacement is scheduled for elective C/S. She has one uneventful vaginal delivery 2 years back. She is booked for LSCS due to breech presentation. She is currently receiving unfractionated heparin on twice daily dose and has discontinued warfarin 6 days back. How will you manage this patient?
Anticoagulants commonly used in pregnancy and recommendation for neuraxial block. Management of the pregnant patient receiving warfarin. Management of pregnant patient receiving unfractionated heparin. Diagnosis and treatment of spinal hematoma.
Management of a pregnant woman with prosthetic heart valve and Anticoagulation
Anti-Coagulants in pregnancy
Anti coagulation in Pregnancy Warfarin. Unfractionated Heparin. LMWH
Hypercoaguable state of pregnancy vWF, fibrinogen, and factors VII, VIII, and X. Protein S, the activity of t PA. Hypervolemia - the integrity of the vessel wall. Obstet Gynecol Clin N Am 33 (2006) 481–491 The risk of venous thrombosis in pregnant women has been estimated to be up to 5-10 times greater than in nonpregnant women of the same age. JAMA 1986;256:744–9. ObstetGynecol 1999;94:595–9.
Thrombosis of prosthetic heart valves during pregnancy The risk of thomboembolism - Bjork-Shiley tilting disc prosthesis vs. St. Jude valve. Obstet Gynecol Clin N Am 33 (2006) 481–491. Valve thrombosis - resultant mortality rates are as high as 10% to 40%. Br Heart J 1993;71:196–201. Thrombolysisvs surgery(high risk of fetal loss). Obstet Gynecol Clin N Am 33 (2006) 481–491.
Warfarin First trimester - coumadin embryopathy. Facial abnormalities, optic atrophy, digital abnormalities, epithelial changes, and mental impairment. JAMA 1985;243:1549–51. Risk is highest, 6-12wks of gestation. Effect of warfarin on calcium deposition and bone formation during embryologic ossification. Am J Med 1980; 68:122–140. Anesthesiology Clin 26 (2008) 1–22 Incidence - 5% to 30%. Am J Cardiol 1989;63:1462–5. Bleeding in the fetus. ThrombHaemost 1989; 61:197–203
Dose related Effect 43 women. 58 pregnancies. Warfarin throughout pregnancy for having a prosthetic valve . The target INR - 2.8. 2 groups > 5mg. < 5mg.
Cont… 27 fetal complications. 22 abortions, 2 warfarinembryopathies, 1 stillbirth, 1 VSD. and 1 growth restriction. 22 in >5mg. Warfarinembryopathies in >5mg. J Am CollCardiol 1999;33:1637–41
Unfrationated heparin Does not cross placenta. 17,500 to 20,000 IU - Q12H. Target aPTT – 1.5-2.5X control. Increased dosing required.
WarfarinvsUnfractionated Heparin Systematic review. 976 women with 1234 pregnancies 1966 to 1997. Three groups, Use of VKAs throughout pregnancy. Replacement of VKAs with UFH from 6 to 12wks. UFH use throughout pregnancy.
Results Coumadin embryopathy – 6.4%. Substitution of UFH for warfarin during 6 - 12wk of gestation eliminated its occurrence. Fetal wastage (spontaneous loss, stillbirths, and neonatal deaths) – similar.
Cont… Valve thrombosis with Warfarin - 3.9%. Valve thrombosis with heparin – 9.2%. Maternal risk of death - 4.2% when heparin is substituted for warfarin in the first trimester. 1.8% when warfarin is used throughout pregnancy. Chan et al. Arch Intern Med 2000;160:191–6.
LMWH Less HIT. Lower risk of heparin induced osteoporosis. Longer plasma half life.
LMWH Comparison of enoxaparin with warfarin and unfractionated heparin in pregnant women who have prosthetic heart valves.(110) The safety committee terminated the study after only 12 patients were enrolled due to two deaths from prosthetic valve thrombosis in the enoxaparin group. Subtherapeutic levels of factor Xa. Am J ObstetGynecol 2004;191:1024–9.
Cont… Warning from LMWH manufacturer. FDA Warning
Aspirin Low dose (60 to 150 mg/d) aspirin therapy administered during the second and third trimesters of pregnancy is safe. JAMA 1991; 266:260–264. (metaanalysis) Lancet 1994; 343:619–629. (RCT)
Use of antithrombotic agents during pregnancy: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy
Cont… Adjusted-dose, twice-daily LMWH throughout pregnancy in doses adjusted either to keep a 4-hour postinjection anti-Xa heparin level at approximately 1.0 to 1.2 U/mL (preferable) or according to weight (Grade 1C), or Aggressive adjusted-dose UFH throughout pregnancy: i.e., administered SC every 12 hours in doses adjusted to keep the mid-interval aPTT at least twice control (Grade 1C), or Bates S.M. et al. Chest 2004;126:627S-44S.
Cont… UFH or LMWH (as above) until the thirteenth week, change to warfarin until the middle of the third trimester, and then restart UFH or LMWH (Grade 1C). Long-term anticoagulants should be resumed postpartum with all regimens. In women with prosthetic heart valves at high risk, add low-dose aspirin, 75 to 162 mg/day (Grade 2C).
Bates S.M. et al. Chest 2004;126:627S-44S.
European Society of Cardiology and American Collegeof Cardiology/American Heart Association Use of warfarin – 35 wks gestation. If the patient does not wish to use warfarin in the first trimester. Adjusted-dose heparin - aPTT 2 to 3 times control. UFH should replace warfarin - 36th week of pregnancy. Heparin and Warfarin - 4 to 6 hours after delivery. Circulation 1998;98:1949–84.
European Society of Cardiology 2007 Low-dose aspirin (75 to 162 mg/day) might be added to women deemed to be at high thromboembolic risk. Close collaboration among the patient, cardiologist, and obstetrician is required, and a thorough discussion of the risks and benefits of various anticoagulation strategies must be held. In a pregnant woman with a mechanical prosthesis, the choice of anticoagulant therapy during the first trimester should take into account the greater thromboembolic risk with heparin and the risk of embryopathy with vitamin K antagonists. The use of vitamin K antagonists during the first trimester is the safest regimen for the mother, and the risk of embryopathy is thought to be very low if the warfarin dose is ≤5 mg/day. Delivery should, if possible, be planned and its modality discussed in close collaboration with the obstetricians and anesthetists. Eur Heart J 2007; 28:230.
Conclusion and Recommendation
Regional Anesthesia Based on 2nd Consensus Conference on Neuraxial Anesthesia and Anticoagulation, 2002). Regional Anesthesia and Pain Medicine 2003: 28:172-197
UFH Heparin > 4 days, aPTT and platelet count prior to neuraxial block and catheter removal. Catheter removal - 2-4 hours after the last heparin dose and the patient's coagulation status is evaluated; Re-heparinization - one hour after catheter removal.
LMWH Traumatic needle or catheter placement may signify an increased risk of spinal hematoma – delay dose 24H. Needle placement 10-12H or 24H. First dose - 24 hours postoperatively. Catheter removal – 10-12 H. Next dose – 2H.
Warfarin D/C :- 4-5 days prior to the planned procedure. PT/INR. Catheters removal - when the INR is <1.5.
Special Considerations Neurologic testing of sensory and motor function should be performed routinely during epidural analgesia. The type of analgesic solution should be tailored to minimize the degree of sensory and motor blockade. These checks should be continued after catheter removal for at least 24 hours.
Spinal Epidural Hematoma
Spinal Epidural Hematoma Accumulation of blood. Epidural veins are valveless and are located in the low-pressure epidural space. Increase in intraabdominal or intrathoracic pressure (as in the Valsalva maneuver), is transmitted to these veins. Neurosurgery 1997;41:483–487 The epidural venous plexus - most prominent in the thoracic spine.
Spinal Haematoma Incidence < 1% of spinal space-occupying lesions. Spine 1998;23:1810–1813. < 1 in 150,000 epidural. < 1 in 220,000 spinal anesthesias. AnasthesiolIntensivmedNotfallmedSchmerzther 1993;28:179–181. 1:200,000 in labor epidural. 1:3,600 for knee arthroplasty. Evidence-Based Practice of Anesthesiology: Expert Consult By Lee A. Fleisher p346.
Risk factors Old age. Female gender. Anticoagulated or thrombocytopenic patient. The length and intensity of anticoagulation. Thrombolytic therapy represents the greatest risk factor for bleeding complications. Liver or renal disease. Evidence-Based Practice of Anesthesiology: Expert Consult By Lee A. Fleisher p346.
Diagnosis Pain. Localized ache + nerve root pain. Back pain percussion over the spine, coughing, sneezing, or straining. Sensory disturbance and dyskinesia. Weakness. Urinary or Fecal incontinence. J Neurosurg 1995;83:1–7.
Management D/C anti coagulants or anti platelets. CBC, PT and aPTT. Steroids to prevent secondary injury. Nonoperative treatment with good outcome Hematomas localized at the caudaequina level With mild neurologic deficit. Emergency removal of Hematoma (Laminectomy). The golden operative period - within 8 hours after the appearance of symptoms, and the period can be extended to 48 hours for those with incomplete paralysis. Neurosurgery 1996;39:494–502. Remove blood clot, stop bleeding, and place drainage-tube. YU Hang-ping, Chinese Medical Journal 2007; 120(15):1303-1308.
Practical Approach for suspected SEH
Management of a pregnant woman with prosthetic heart valve and Anticoagulation
History Reason for MVR. Duration. Other comorbids (A Fib.) Any complications during previous delivery. Current medications. Functional status.
Examination Vitals. BMI Airway and Back. Chest and cardiac auscultation.
Investigations CBC PT, aPTT. ECG Review Echo and CXR
Pre Operative Routine. Blood products. D/C Warfarin at 36 wks. Heparin/LMWH. D/C Heparin 6H > surgery. GA vs. regional (Spinal). BE Prophylaxis at Delivery.
Intra Op Risk of Bleeding. Large bore IVs.
Post op Resume anticoagulation. Analgesia. F/up for hematoma if regional was employed.