Treatment of patients with suspected subsegmental PE seen on CT

Dr Wendy Lim is a professor in the Division of Hematology and Thromboembolism at McMaster University.

Should we treat patients with suspected subsegmental pulmonary embolism seen on computed tomography (CT)?

Wendy Lim, MD, MSc: That is a really controversial area. As you know, a lot of times these small subsegmental [instances of] pulmonary embolism (PE) are picked up incidentally on diagnostic imaging done for other reasons. I think if it is asymptomatic, it is hard to say because we need to really assess what clinical context it is occurring in.

My personal practice is that a lot of times these scans are done in the setting of cancer, so they are being done as part of staging for cancer or perhaps are being done to evaluate the response to a treatment. So if the patient has cancer and they are found to have subsegmental PE, I typically am up to treat if I do not think that their bleeding risk is too high and I am exposing them to unnecessary risk.

In the absence of cancer, I would weigh whether it is associated with symptoms or not, I would weigh their bleeding risk, and then make a decision. So there may be patients who I do end up treating and others who I do not. This is really an area that is perfect for further research and there are studies that are going on looking at that very question.