Thread by @PulmCrit

Fresh RCT on IVC filters! 240 trauma patients with initial contraindication to DVT prophylaxis randomized to IVC filter vs no filter. Primary endpoint was a composite of symptomatic PE or death. The first evident problem is *power*… (#rantorial, 1/7...)
nejm.org/doi/full/10.10…

Study was powered based a 25-year-old data showing a 9% risk of PE in patients with *no* DVT prophylaxis. But, advances in trauma care, pneumatic compression devices, & initiation of chemical prophylaxis ASAP have reduced this rate, leaving the study underpowered (2/7).

The primary endpoint is a composite of death or symptomatic PE. Since PE is uncommon & most deaths aren’t due to PE, the composite endpoint is overall driven simply by death. As would be expected, there is no difference (3/7).

Now things get more confusing. The secondary endpoints of interest are rates of venous thromboembolic disease (DVT, PE, and IVC filter thrombosis). However, symptomatic PE is only reported in a small subset of patients who never got DVT prophylaxis ?? 🤷‍♂️ (4/7)

There are fewer PEs in patients who never received DVT prophylaxis & were treated with a filter (0/46 vs. 5/34). But this is a *secondary* endpoint in a *subset* of patients which puts its two degrees of goodness away from the primary endpoint. Kevin Bacon doesn’t approve (5/7)

IVC filters did cause a fair number of problems. One required surgical removal (😱) and in many cases they couldn’t be removed. Who knows the long-term harm from these chronic filters? (unknowable within this study’s time-frame)(6/7).

summary:
- Effect of IVC filter unclear 2/2 underpowering & subgroup analysis
- IVC filters = pesky buggers, can cause problems
- PE rate lower w/ modern trauma care
- Best approach maybe pneumatic compression & chemical prophylaxis ASAP
(7/7)
#NoFilter
emcrit.org/pulmcrit/what-…