Sort Out New VTE Prophylaxis Data in COVID-19 Patients

New evidence will spark debate about the intensity of venous thromboembolism (VTE) prophylaxis for hospitalized COVID-19 patients.

These patients seem to have higher VTE risk. But data about the optimal VTE prevention strategy are dosing varies.

Some experts use full-dose anticoagulation for VTE prophylaxis...or "full-dose VTE prophylaxis"...such as enoxaparin 1 mg/kg BID.

Others may use "intermediate-dose VTE prophylaxis"...such as enoxaparin 1 mg/kg daily.

Now new evidence in CRITICALLY ill COVID-19 patients does NOT show benefit when using full- or intermediate-dose VTE prophylaxis...compared to standard dose, such as enoxaparin 40 mg/day.

On the other hand, new data in MODERATELY ill COVID-19 patients suggest full-dose VTE prophylaxis reduces the need for ICU-level care versus standard dose. But overall mortality doesn't seem to be decreased.

The theory is that low-molecular-weight and unfractionated heparins have anti-inflammatory effects that may provide benefit BEFORE disease progresses.

Caution that even though bleeding risk doesn't seem to be increased, more data are needed to confirm this.

Plus current studies are mostly in low-bleeding-risk patients...with normal renal function, under age 75, and NOT taking an antiplatelet.

Point out that "moderately ill" often EXCLUDES patients requiring high-flow oxygen, noninvasive ventilation, or pressors...regardless of hospital location.

And most patients in these trials started full-dose VTE prophylaxis within a few days of admission.

Ensure ALL hospitalized COVID-19 patients receive VTE prophylaxis.

Stick with standard-dose VTE prophylaxis for critically ill patients AND most moderately ill patients.

Limit full-dose VTE prophylaxis to moderately ill patients who don't require aggressive respiratory support, such as noninvasive ventilation...and with LOW bleeding risk.

Weigh decisions about full-dose VTE prophylaxis on a case-by-case's too soon to say which patients will benefit the most.

Generally go with low-molecular-weight heparin (LMWH)...since unfractionated heparin increases nursing exposure to COVID-19 patients.

And continue to adjust LMWH doses for renal function and weight.

Get our FAQ, COVID-19 and Thromboembolism, to find answers about monitoring, whether to use extended-duration VTE prophylaxis, etc.

Key References

  • N Engl J Med 2021;385(9):777-89
  • N Engl J Med 2021;385(9):790-802
  • JAMA 2021;325(16):1620-30
  • medRxiv Published online Jul 12, 2021; doi:10.1101/2021.07.08.21259351
Hospital Pharmacist's Letter. October 2021, No. 371021

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