Deep vein thrombosis resident survival guide
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Abdurahman Khalil, M.D. [2]
Definition
Deep vein thrombosis (also known as deep venous thrombosis or DVT and colloquially referred to as economy class syndrome) is the formation of a blood clot ("thrombus") in a deep vein. The risk is significantly increased if the thrombus embolizes to the lungs, causing pulmonary embolism.
Causes
Life Threatening Causes
Include conditions which may result death or permanent disability within 24 hours if left untreated.
Common Causes
- Long term immobility
- Coagulation disorders
- Cardiac failure
- Hip replacement
- Estrogen in OCP and HRT
- Nephrotic syndrome
- Obesity
- Pregnancy
Diagnostic approach
| Pain Swelling Erythema Venous dilation | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Pretest Probability of DVT Major points 1-Active cancer 2-Paralysis,paresis or plastic immobilization of leg or foot 3-Recent bed rest >3 days or major surgery in the last 4 weeks or both 4-Calf or thigh swelling 5->3 cm calf swelling below the tibial tuberosity 5-Strong F/H of DVT Minor points 1-H/O recent trauma to the suspected leg 2-Pitting edema in the suspected leg 3-Dilated superficial veins in the suspected leg 4-Hospitalization in the last 6 months 5-Erythema | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Low probability* | Moderate probability* | High probability* | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| D-Dimer | D-Dimer | U/S | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Negative | Positive | Negative | Positive | Negative | Positive | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| No DVT | U/S | No DVT | U/S | Repeat in 7 days | D-Dimer | Treat | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Negative | Positive | Negative | Positive | Negative | Positive | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| No DVT | Treat | Repeat in 7 days | Treat | No DVT | Repeat in 7 days | U/S[1] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
- High probability:
>3 major points+ no alternative diagnosis
or 2 major points + 2 minor points + no alternative diagnosis. - Low probability:
1 major point +≥2 minor + alternative diagnosis
or 1 major + ≥1 minor + no alternative diagnosis
or no major points+ irrespective of minor points +irrespective of diagnosis. - Moderate probability:
neither high or low probability.[2]
According to Institute for Clinical Systems Improvement (ICSI), U/S should be used as initial test for moderate probability rather than high sensitivity D-dimer.[3]
Management
| DVT confirmed | |||||||||||||||||||||||||||||||
| Hemodynamically unstable(massive PE) SBP<90 mm Hg or 40 mm Hg drop Syncope Severe hypoxemia or respiratory distress | Hemodynamically stable | Contraindication for Anticoagulation therapy Absolute Active severe hemorrhage Intracranial hemorrhage Relative Recent surgery, trauma, anemia,GI bleeding, PUD | |||||||||||||||||||||||||||||
| Thrombolytic therapy | LMWH or UFH(target INR:2.5, monitor Plt count)+ Warfarin or Fondaparinux | IVC filter | |||||||||||||||||||||||||||||
Do's
- For moderate to high probability suspicion start initial therapy while waiting for diagnostic results, when there is a low probability the decision of treatment will depend on the diagnostic results.
- Start vitamin K antagonist(Warfarin) no more than 1 or days after start UFH or LMWH.The initial dose for the first 2 days should be 10 mg daily then in accordance to the required INR measurements.
- INR therapeutic ranges are 2.0-3.0 and Target INR is 2.5 and that is applied for patients with hypercoagulable state (antiphospholipid syndrome).
- For IV UFH administration use weight adjusted dose for the initial bolus(80 unit/kg) and the following continuous infusion(18 unit/kg/hr), and for subcutaneous UFH (first dose 333 units/kg, then 250 units/kg).
- For patients with CKD/ESRD reduce LMWH than standered dose.
- Fondaparinux administered subcutaneously in fixed doses 7.5 mg and if the patient weight>100 kg the dose will be 10 mg.[4]
Don'ts
Avoid with VKA therapy all of the following:
- NSAIDs including cox-2 inhibitors.
- Antiplatelet unless benefit outweighs harm (ACS, mechanical valves, coronary stents or bypass surgery).
- Vitamin K supplement(not recommended).
References
- ↑ Bates SM, Jaeschke R, Stevens SM, Goodacre S, Wells PS, Stevenson MD; et al. (2012). "Diagnosis of DVT: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines". Chest. 141 (2 Suppl): e351S–418S. doi:10.1378/chest.11-2299. PMC 3278048. PMID 22315267.
- ↑ Wells PS, Anderson DR, Bormanis J, Guy F, Mitchell M, Gray L; et al. (1997). "Value of assessment of pretest probability of deep-vein thrombosis in clinical management". Lancet. 350 (9094): 1795–8. doi:10.1016/S0140-6736(97)08140-3. PMID 9428249.
- ↑ Skeik N, Dupras D (2013 Jan). "Venous Thromboembolism Diagnosis and Treatment". Institute for Clinical Systems Improvement (ICSI). Check date values in:
|date=(help) - ↑ Holbrook A, Schulman S, Witt DM, Vandvik PO, Fish J, Kovacs MJ; et al. (2012). "Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines". Chest. 141 (2 Suppl): e152S–84S. doi:10.1378/chest.11-2295. PMC 3278055. PMID 22315259.