PB 84: Prevention of Deep Vein Thrombosis and Pulmonary Embolism Flashcards
DVT is diagnosed in ~2 million Americans each year. Approximately how many of these patients develop a pulmonary embolism?
What is the rate of VTE after gynecologic surgery in the untreated population?
15-40%
How is the risk of VTE determined at time of surgery?
- Procedure type and duration
- Age
- Presence of other risk factors
Risk classification for VTE in patients undergoing surgery without prophylaxis?
What are 4 types of
- Graded compression stockings
- Pneumatic compression devices
- Unfractionated heparin
- LMWH
Does a combined regimen of medical and mechanical prophylaxis improve efficacy of reducing VTE?
What are the 2 most common mutations found in patients with a VTE?
- Factor V Leiden
- Prothrombin gene mutation G20210A
Do most inherited factors of a hypercoagulable state result in clot formation?
What is the most common inherited thrombophilia?
Factor V Leiden: major cause of activated protein C resistance (carried by 5% Caucasians)
Heterozygotes: 3-8 fold increased risk of VTE
Homozygotes: 50-80 fold increased risk of VTE
How are deficiencies in Protein C, Protein S, and Antithrombin-III diagnosed?
Serum assays
Common hypercoagulable states
Within what time period after surgery do most thrombi develop?
Nearly 50% within 24 hours after surgery, 75% within 72 hours of surgery
Pre-operative heparin use has been associated with what 2 things post-operative?
- Increased postoperative bleeding
- Hematoma formation
* DOES NOT INCREASE OPERATIVE EBL *
What to look out for if heparin is going to be used for > 4 days?
Heparin-induced thrombocytopenia (6% of patients) > follow platelets
Advantages of LMWH over unfractionated heparin?
- Greater bioavailability
- Once-daily dosage
- More antifactor Xa and less AT-III activity > may decrease medical bleeding and wound hematoma formation
- HIT rarely seen
Should patients discontinue use of hormonal contraceptives or postmenopausal hormone therapy before surgery?
No
Although VTE is associated with estrogen and progesterone use, the overall number of events is low. No trials exist that show a reduction in postsurgical venous thromboembolism with preoperative discontinuation of hormone therapy; thus, this practice should not be routinely recommended.
Herbs and supplements that may interfere with anticoagulant therapy
