Venous Thromboembolism (VTE) Prophylaxis at Cesarean Section Phillip N. Rauk, MD

Surgical Care Improvement Project (SCIP Measures) Infection Cardiac Venous Thromboembolism –Process Measures Prophylaxis ordered Prophylaxis received 24 hrs before to 24 hrs after surgery –Outcome Measures PE (and DVT) diagnosed during hospitalization and within 30 days of surgery Respiratory

Objectives Review the epidemiology of venous thromboembolism (VTE) in pregnancy Relate the pregnancy specific risks to nonpregnant patient population Discuss prophylaxis options

“Scope” of the Problem VTE risk is increased in pregnancy and postpartum 3-5 fold VTE is 3-10 fold higher after CS than vaginal delivery Pulmonary embolism (PE) - leading cause of maternal mortality in the 90’s accounting for 20% of deaths VTE Mortality rate – 1.1/100,000 deliveries in No pregnancy specific data related to prophylaxis in most situations Recommendations are extrapolated from non-pregnant populations CDC 2003, James 2005

VTE Risk Factors Prior VTE Thrombophilia Cancer Age >40 yrs Obesity (BMI>30) Tobbacco Estrogen Therapy Chronic Medical Disease Systemic Infection Vericose Veins Multiparity (>4) Immobilization –Bedrest Preeclampsia Postpartum Hemorrhage Cesarean Section

Natural History of DVT Related to Surgery Majority develop in the calf during surgery 50% will resolve spontaneously within 72 hours 15% with extend into proximal veins 80% of symptomatic DVT involve proximal veins (majority of calf vein DVT’s are asymptomatic) 50% in proximal veins will result in symptomatic pulmonary embolus 40-50% of proximal DVT have asymptomatic PE 10% of PE’s are fatal within one hour of symptoms Kearon, 2003

Timing of DVT StudyTrimester (%) Total in Pregnancy (%) Postpartum (%) 1 st 2 nd 3 rd James, 2005 (n=53) Heit 2005 (n=100) Blanco-Molina 2007 (n=136) Jacobsen 2008 (n=615)

Incidence of VTE (/10,000 units) Population (person yrs) 7 Pregnancy & Postpartum (births) Medical Patients Major Orthopedic Surgery (procedures)* Major General Surgery Pelvic Cases (Procedures)* TAH, Prolapse Surgery, Cancer surgery (Procedures)* Exploratory Laparoscopy (Procedures)* Samama, 2006 ACCP, 2008 *without prophylaxis

Prophylaxis Based on Risk Level of RiskRisk without prophylaxis Prophylaxis Recommendations Low (no risk factors for VTE) Minor surgery Ambulatory <10%No specific prophylaxis; early & aggressive ambulation Moderate ( 1-2 risk factors for VTE) Most surgery patients 10-40%LDUH (q12 hr), LMWH High (>2 risk factors for VTE) Trauma and emergency surgery 40-80%LDUH (q8 hr), LMWH ACCP, 2008

VTE Incidence Greer, 1999

Risks of Heparin Prophylaxis Severe bleeding –Incidence - 1/1000 Heparin-induced thrombocytopenia (HIT) –Incidence – 1%; probably lower in pregnancy –Thrombosis develops (arterial or venous) in 30-50% Collins, 1988 Arepally, 2006

VTE Associated with Cesarean Section “… the risk of VTE is higher after CS than after vaginal delivery. The presence of additional risk factors … may exacerbate this risk. It has been recommended that GCS be used during and after cesarean section in patients at ‘moderate risk’ and heparin prophylaxis be added in those at ‘high risk’. However there is insufficient data to provide information as to the benefits with these interventions.” ACCP 2004

ACCP Cesarean Section Prophylaxis Recommendation “… without additional risk factors … we recommend against the use of specific thromboprophylaxis other than early mobilization” (Grade 1B) … in the presence of at least one additional risk factor pharmacologic thromboprophylaxis or mechanical prophylaxis while in hospital recommended. (Grade 2C) ACCP 2008

Pneumatic Compression Device Prophylaxis for Cesarean Section Prophylaxis Strategy HITHIT induced Thrombosis Major Bleeding VTE No prophylaxis Heparin PCD Incidence per 10,000 Cesarean Sections Quinones, 2005

Pneumatic Compression Device Prophylaxis for Cesarean Section Cost effective with following assumptions –Incidence of DVT > 6.8/ % are asymptomatic –DVT reduced > 50% –Cost of PCD < $180 Casele, 2006

Graded Compression Stockings Control GroupOR95% CI No prophylaxis vs GCS (n=1027) Prophylaxis vs Prophylaxis plus GCS (n=1184) Amaragiri, Cochrane Collaboration, 1999

Limitations of Mechanical Devices Compliance –Both GCS and PCD removed due to discomfort Improper fit “Strangulation” with GCS

Cost of Mechanical Devices DeviceCost PCD Foot$61.54 Foot Reprocessed$18.00 Knee$20.00 Knee Reprocessed$12.00 GCS Knee$3.17

Risk Factors (#) RiskTreatmentRiverside (% cases) Southdale (% cases) 0LowEarly ambulation ModerateEarly Ambulation Stockings ModerateEarly Ambulation Stockings 18 >2HighEarly Ambulation Stockings LMWH 194

Summary Objective data to guide VTE prophylaxis for CS is very limited In the absence of data “First do no Harm” Individualize heparin therapy and reserve it for the highest risk patients – previous VTE, thrombophilia, multiple risk factors (elderly gravida, obese, severe preeclampsia, at bed rest) Early ambulation alone is acceptable and recommended for many CS patients GCS or PCD are acceptable and may be cost effective