Interview with hematologist Dr. Tom Deloughery about a smattering of clotting quagmires…Superficial Thrombophlebitis, Recurrent Pulmonary Embolism, Calf Vein DVT, Clotted PICC Lines, Starting (loading) dose of warfarin, low molecular weight heparin, widowmaker clots.
Quandary 1. Recurrent pulmonary embolism
Your patient is on warfarin, INR is therapeutic and has another PE. What do you do?
Make sure it’s truly recurrent. If it is…
- How long have they been on anticoagulation? If it’s only a week, then the warfarin may not have had time to provide any benefit.
- If longer than a week and their INR has been therapeutic the whole time, consider that a warfarin failure. Start LMWH. This is a worrisome sign for an underlying malignancy or coagulopathy. LMWH is superior to warfarin for recurrent thromboembolic disease.
- On warfarin for years and has a recurrent PE. Do they get life long LMWH? Give LMWH for 3-6 months and, if they’re stable, restart the oral anticoagulant.
First dose of warfarin
1. How long to you need to wait to start warfarin after the first shot of LMWH? You can start both meds at the same time.
2. Is there a need for a loading dose of warfarin? Sort of….Dosing and effect are unpredictable. As a general rule, Tom gives young and otherwise healthy patients 10mg as a first dose. Over 65 or young and frail, first dose 5mg.
3. If your patient needs to restart warfarin after being off it for a while, do you need to bridge with LMWH until the INR is therapeutic? In the setting of DVT and PE, yes. In atrial fibrillation, you probably don’t .
Can clot in the saphenous vein progress to DVT? Yes. 5-10%. Non saphenous vein clots progress to DVT at a rate of about 1%. As saphenous vein clot gets closer to the femoral vein, risk rises of it becoming a deep clot, but there are also perforator veins all along the saphenous vein that connect it to the deep system. Clot can connect from the superficial (saphenous) vein to deep vein through a perforator at any point, but it’s less of a worry than deep propagation directly into the femoral vein near the groin.
Treating superficial thrombophlebitis needs to take into account the ‘thrombo’ (clot) and ‘itis’ (inflammation)
NSAIDS decrease rate of inflammation and clot extension
Therapeutic vs prophylactic LMWH: both decrease rate of inflammation and clot extension – outcomes are equal, so prophylactic LMWH is preferred (once a day, lower dose)
Small, under 5-7cm and not proximal (not upper half of thigh) NSAIDS
Larger than 5- 7cm or proximal, prophylactic dose of LMWH or fondaparinux (40mg daily)
Duration of therapy
There is uncertainty as to the optimal duration of therapy. Tom treats for two weeks. If patients are still symptomatic, treat for another two weeks.
Upper extremity thrombophlebitis
It is thought that upper extremity superficial thrombophlebitis has a more benign course. Treat with NSAIDS and hot packs. If this isn’t working, transition to LMWH.
What should you do with a PICC line clot?
Anticoagulation does not help with recannalization. Pull the line.
Putting in a new PICC right away – high rethrombosis rate.
Calf vein DVT
15-30% will grown and cause PE. Follow up ultrasound to check for extension is an option.
Unless there is a contraindication, treat with anticoagulation. ACCP recommends 3 months of treatment, Tom treats for 6 weeks.
Factor V Leiden mutation
9% prevalence in Portland, OR. Mostly a caucasion disease. Raises risk of first clot 3 fold (more DVTs than PE). Having this mutation does not increase risk of DVT recurrence.
Bonus point of the day
The SUPERFICIAL femoral vein is a DEEP vein. Perhaps the worst anatomic name ever. If you get a report that your patient has clot in the superficial femoral vein, that is a DVT, not superficial thrombophlebitis.