What This Means
This research examined how often small, peripheral blood clots in the lungs (called segmental and subsegmental pulmonary embolisms, or PE) are found in intensive care unit (ICU) patients, how they are treated, and what happens to these patients afterward. Researchers reviewed over 800 ICU patients who had CT scans of their lung arteries at a single Australian hospital over about six years. They found that roughly 1 in 8 of all these CT scans showed these smaller, more peripheral clots, and that nearly all affected patients were treated with full ('therapeutic') doses of blood thinners — similar to how larger, more dangerous clots are typically managed.
Despite the widespread use of therapeutic anticoagulation, the study found that bleeding occurred in 15% of patients (with serious bleeding in 12%), while clot recurrence happened in about 8% and 90-day mortality was 24%. Importantly, no statistically significant link was found between receiving full-dose blood thinners and better or worse outcomes — including death, bleeding, or new clots. However, the study was limited by its small size and single-center, retrospective design, meaning it could not definitively prove or disprove that stronger anticoagulation helps or harms these patients.
This research suggests that ICU doctors frequently treat these smaller lung clots aggressively with full-dose anticoagulation, even though the benefit of this approach over lower-dose or no anticoagulation remains unclear. Given that bleeding was more common than clot recurrence in this critically ill population, the findings highlight an important clinical uncertainty. The authors call for larger, prospective studies to determine the safest and most effective treatment strategy for ICU patients with these peripheral lung clots.