Blunt Chest Trauma-Induced Left Internal Mammary Artery Injury Requiring Interventional Radiology Embolization: A Case Report

Internal mammary artery (IMA) injuries caused by blunt chest trauma are rare and can prove to be fatal; diagnosis is often missed due to the variety of patient presentations. IMA injury can also occur after lower-energy mechanisms, and management standards and treatment guidelines for these injuries remain limited. If left undetected, severe consequences, including life-threatening intrathoracic hemorrhage, may occur. Therefore, prompt and accurate diagnosis is essential following blunt chest trauma. We present a unique case of a 60-year-old male patient who sustained an injury to the left IMA after falling from his bicycle. The patient's hemoglobin and hematocrit were 10.5 g/dL and 29.8%, respectively. His systolic blood pressure decreased from an initial 171 mmHg to the 80s while in the emergency department. Computed tomography (CT) of the chest, abdomen, and pelvis with contrast showed a large subcutaneous hematoma overlying the left pectoralis muscle with a small focus of active extravasation. Urgent coil embolization was done by interventional radiology (IR) to occlude an area of active bleeding arising from a branch of the left internal mammary artery. A post-procedural angiogram revealed resolution of active bleeding. The patient remained neurologically and hemodynamically stable, his hemoglobin stabilized, and he was cleared for discharge home after physical therapy and occupational therapy evaluation. At trauma clinic follow-up, his left chest wall swelling had significantly improved without post-procedural complications. Patients with IMA injuries may initially present with mild symptoms and limited external findings following minor trauma. However, an undiagnosed IMA injury can cause fatal hemorrhage. Clinicians should therefore include IMA injury in the differential diagnosis for patients with blunt anterior chest trauma, enlarging chest wall hematoma, hypotension, or active extravasation on imaging. CT angiography can effectively identify active extravasation and guide definitive angiographic management. As demonstrated in this case, embolization can provide rapid and effective hemorrhage control in selected patients and may avoid the morbidity of open surgical repair.