PE Guidelines Say LMWH…Why So Much UFH?

Written by Bo Stubblefield

Guidelines recommended low molecular weight heparin (LMWH) for most patients with acute pulmonary embolism (PE), but we often choose unfractionated heparin (UFH). Here’s why…

“In a dark place we find ourselves, and a little more knowledge lights our way…”
A recent study of nearly 300,000 patients hospitalized with acute PE between 2011-2020 found that the use of UFH increased from 41.9% to 56.3%, in spite of guideline recommendations for LMWH.¹ Outside the U.S., UFH use has gone down, steadily declining below 10%.² Only one-fourth of patients with PE who receive UFH are therapeutically anticoagulated at 24 hours.³ So, why are we using so much UFH? What is driving this guideline-disconcordant care?

This qualitative study interviewed 46 physicians in emergency medicine, hospital medicine (hospitalists), interventional cardiology, and interventional radiology. There were several important themes identified to help explain the why behind initial anticoagulation choice in hospitalized patients with acute PE. Central themes are mapped in Fig. below and are, in summary: 1) agnosticism of anticoagulant choice, 2) inertia of learned practice, 3) institutional culture, and 4) therapeutic momentum.

How does this change my practice?
Once we know why we choose poorly, we can begin to address our choices. LMWH should be our go-to anticoagulant. With LMWH, patients are much more likely to be therapeutically anticoagulated, experience fewer bleeding events, and have lower risk for medication management errors. Although we may worry about the potential for decompensation and don’t want to preclude advanced therapies, this fear is unfounded. Most patients hospitalized with PE undergo neither systemic thrombolysis nor catheter directed procedures, and – even if they do – administration of LMWH is not a contraindication to such therapies.