Preventing DVT and PE in Nonsurgical Patients
from the ACCP Guidelines, 9th Ed.
The ACCP‘s new 9th edition of their authoritative clinical practice guidelines for prevention and treatment of venous thromboembolism (VTE) were published in February 2012, and we’ll be summarizing the 801-page long document piece by piece.
Here we review the section on prophylaxis of deep venous thrombosis (DVT) and pulmonary embolism (PE) in nonsurgical / medical patients. Also see the other sections of the ACCP 9th edition DVT/PE recommendations we’ve reviewed.
1. Patients at Low Risk for DVT/PE Require NO Prophylaxis
That’s right: “For acutely ill hospitalized medical patients at low risk of thrombosis, [ACCP] recommends against the use of pharmacologic prophylaxis or mechanical prophylaxis” (Grade 1B; 1 = recommendation; B = moderate-quality evidence)
How can you determine your patient’s risk? Use the Padua Prediction Score; although imperfect, it’s the best available validated predictor for DVT/PE risk. Patients scored as low-risk by the PPS have a 0.3% rate of symptomatic DVT-PE in 90 days, and no longer require prophylaxis by ACCP guidelines. (Those who are high-risk on the PPS who do not receive prophylaxis have an 11% rate of DVT-PE within 90 days.)
Critically ill patients are at elevated risk for DVT-PE and should receive prophylaxis; don’t use the Padua tool on them.
The change in emphasis away from universal prophylaxis comes from a comprehensive evidence review that suggested harm from bleeding in low-risk patients given low-dose heparin, and skin necrosis in stroke patients given compression stockings. The American College of Physicians (the mother ship for internal medicine doctors) collaborated, and released their own recommendations against universal DVT/PE prophylaxis earlier this year.
2. Give Anticoagulant Prophylaxis to Patients at Elevated DVT-PE Risk, incl. the Critically Ill
Patients at moderate or high risk by the Padua Prediction Score who are not bleeding or at high risk for bleeding should be given anticoagulant thromboprophylaxis with either low-molecular weight heparin (enoxaparin/Lovenox or others), unfractionated heparin (either b.i.d. or t.i.d), or fondaparinux (Grade 1B; 1 = recommendation; B = moderate-quality evidence).
This recommendation includes all critically ill patients, as long as they are not at high bleeding risk.
ACCP recommends against screening for asymptomatic DVT with routine ultrasounds in critically ill patients (Grade 2C; suggestion based on consensus/poor evidence). The natural history of incidentally discovered, asymptomatic DVT is unknown; many of these DVTs regress spontaneously, and prescribing months/years of anticoagulation to these patients wholesale could result in excess bleeding, is likely the authors’ concern.
3. For Patients who are Bleeding or at Risk for it, Use Leg Compression Devices Only
Intermittent pneumatic compression devices or graduated compression stockings should be used for patients who are bleeding or at high risk for it (Grade 2C; suggestion based on consensus/poor evidence). Switch them to anticoagulant prophylaxis as soon as bleeding risk is considered to be low (Grade 2B; suggestion based on moderate-quality evidence).
Predicting bleeding risk in hospitalized patients is difficult; no validated, reliable tool exists, according to these authors. Relying mainly on a single large observational study, the authors considered patients to be high risk (favoring compression devices over anticoagulant prophylaxis) if they met any of the following criteria, which were the strongest predictors of bleeding (odds ratios > 3):
- Active gastroduodenal ulcer;
- Bleeding in the 3 months prior to admission;
- Platelet count < 50,000;
or if they had “multiple risk factors” for bleeding of lesser predictive strength, including age > 84; hepatic failure with INR > 1.5; severe renal failure; ICU/CCU admission; a central venous catheter in place; rheumatic / autoimmune disease; current cancer; and male sex.
4. Some Outpatients With Cancer Should Take Daily Heparin Prophylaxis
Outpatients with cancer and additional risk factors for VTE (previous DVT/PE, immobilization, angiogenesis inhibitors, hormonal therapy, lenalidomide, thalidomide) should take low molecular weight heparin or low dose unfractionated heparin as DVT-PE prophylaxis (Grade 2B; suggestion based on moderate quality evidence).
Without these risk factors, heparin prophylaxis is not recommended (Grade 2B), nor warfarin/coumadin (Grade 1B), even if they have an indwelling central line (Grade 2B against heparin / Grade 2C against warfarin).
5. High-Risk People On Long Plane Flights Should Walk, Consider Compression Stockings
These are all Grade 2C; suggestion based on consensus/poor evidence:
- People at elevated risk for DVT/PE (previous history of DVT/PE, hypercoaguable state or thrombophilia, cancer, pregnancy, use of estrogens, severe obesity) should get up and walk around the place periodically, flex their calf muscles, and sit in an aisle seat when possible.
- They should also consider the use of below-knee graduated compression stockings at 15-30 mm Hg during the flight.
- No one should take aspirin or anticoagulants as prophylaxis against DVT-PE on a long flight.
- People not at elevated risk for DVT/PE by the above criteria are at exceedingly low risk for DVT/PE on a plane flight of any duration, and need take no precautions.
6. People with Thrombophilia but no History of DVT/PE Should Not Take Anticoagulation Prophylaxis
Unless that person has experienced a DVT/PE, no one with an incidentally detected hypercoagulable state or thrombophilia (factor V Leiden; prothrombin gene mutation; antithrombin deficiency; protein C deficiency; protein S deficiency; and antiphospholipid antibody syndrome / lupus anticoagulant / anticardiolipin antibody syndrome) is recommended to take anticoagulant prophylaxis or aspirin to prevent DVT/PE (Grade 1C; recommendation based on consensus/weak evidence).
We’ll continue to bring you the rest of the new 9th edition ACCP guideline’s recommendations on thromboprophylaxis and treatment of DVT/PE in future weeks, in an easy to reference format. See also:
How to Start and Manage Anticoagulation (warfarin/Coumadin) in Patients with DVT/PE. This segment includes recommendations on how to manage high INRs with and without bleeding.
Kahn SR et al. Prevention of VTE in Nonsurgical Patients. From: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. CHEST 2012;141 (suppl 2):e195S-e226S.