Reperfusion Pulmonary Hemorrhage Following Mechanical Thrombectomy for Sub-massive Pulmonary Embolism.

Mechanical thrombectomy is an increasingly utilized intervention for patients with intermediate-risk pulmonary embolism who demonstrate right ventricular strain. While effective at reducing clot burden and improving hemodynamic parameters, the procedure carries a risk of rare post-interventional complications. This case report describes a 75-year-old woman with a history of breast carcinoma who presented with progressive dyspnea and right lower extremity swelling following recent air travel. Diagnostic imaging revealed a sub-massive right-sided pulmonary artery occlusion and severe right ventricular dilatation with reduced systolic function. The patient underwent successful mechanical thrombectomy, resulting in the removal of large, organized thrombi and immediate improvement in pulmonary blood flow. However, the patient developed acute hypoxia shortly after the procedure. Subsequent radiographic imaging showed extensive new consolidation in the right upper lobe. This condition, characterized by alveolar consolidation in previously occluded territories, can radiographically mimic aspiration or procedural trauma. The diagnosis of reperfusion pulmonary hemorrhage was guided by the presence of flow through the pulmonary vasculature and the absence of contrast extravasation on repeat angiography. The patient was managed with supportive care and supplemental oxygen, leading to clinical stabilization and eventual discharge on oral anticoagulation. This case highlights the importance of recognizing reperfusion injury as a distinct clinical entity following mechanical thrombectomy. Clinicians must distinguish this inflammatory and pressure-related phenomenon from direct catheter-induced trauma to ensure appropriate management and avoid unnecessary intervention.