Would you place an IVC filter in a patient with an acute PE and an absolute contraindication for anticoagulation, but negative imaging for proximal DVT?

Good question. In this scenario, it would be reasonable to place an IVC filter. I would also image the IVC/pelvic veins in an effort to locate the origin of the embolus. A residual clot (depending on the size) may affect the approach to placement of IVC filter. Other variables include whether the PE was segmental or subsegmental, hemodynamic status, and underlying cardiopulmonary comorbidities of the patient. E.g., if subsegmental, and hemodynamically stable and the contraindication to anticoagulation is temporary, one may defer the filter. There are general guidelines on indications for filter placement, which apply to the large majority of patients, but this can get nuanced.

There is likely denuded endothelium in the lower extremity which is likely to set up DVT in the absence of anticoagulation. So IVC filter placement is indicated.

I would like to refer to the recently published Society of Interventional Radiology Clinical Practice Guideline on IVC filter (Kaufman et al, J Vasc Interv Radiol, 2020; PMID: 32919823). This is the first evidence-based guideline, prepared in collaboration with multiple professional societies including ACC, ACP, and AHA.