Traumatic Pseudoaneurysms of the Internal Mammary Artery: Two Cases and Percutaneous Intervention

Abstract

Pseudoaneurysms involving the internal mammary artery/internal thoracic artery (IMA/ITA) are rare occurrences, and the presentation and treatment approaches for such cases can be variable. Due to the potentially life-threatening risk of rupture, leading to conditions like hemothorax, it is important to have a comprehensive understanding of safe and effective diagnostic and therapeutic techniques. We present two cases of IMA/ITA artery pseudoaneurysms. A 91-year-old male presented to the emergency department following a motor vehicle accident. A CT scan of the chest revealed an anterior mediastinal hemorrhage with active extravasation. Percutaneous intervention revealed a pseudoaneurysm arising from a left IMA/ITA side branch. Coil embolization effectively treated the pseudoaneurysm. In the second case, a 79-year-old male presented with a sternal fracture after a ground-level fall, with parasternal hematoma and active bleeding (pseudoaneurysm) on Trauma Computerized Tomography of the chest with contrast. He underwent coil embolization, and subsequent post-procedure angiograms confirmed the effective occlusion of the left IMA/ITA, with no further visualization of the pseudoaneurysm. These two cases underscore the importance of tailored approaches in treating internal mammary artery pseudoaneurysms.

Keywords: CT; internal mammary artery; internal thoracic artery; interventional radiology; percutaneous intervention; pseudoaneurysm.

Figure 1

91M MVA restrained rear seat passenger. (A) CT of the chest with contrast. Focal contrast extravasation consistent with active bleeding site left parasternal anterior mediastinum (green arrow). Left internal mammary artery (red arrow). Anterior mediastinal hematoma (yellow arrows). (B) CT of the chest, bone windows. Sternal fracture (green arrow). (C) CT of the chest with contrast coronal reconstruction. Focal contrast extravasation consistent with active bleeding site left parasternal anterior mediastinum (green arrow).

Figure 2

(A) Selective microcatheter digital subtraction angiogram (DSA) left internal mammary artery (LIMA) extravasation consistent with active bleeding/pseudoaneurysm from side branch of LIMA (white arrow). (B) Microcatheter DSA LIMA post coil embolization. Coils are deposited as a bridge covering the side branch bleeding source, sometimes referred to as sandwich technique or “jailing technique”, to eliminate antegrade as well as any retrograde or collateral flow to the bleeding side branch. No further extravasation. (C) Microcatheter “native” non-subtracted digital angiogram better demonstrates the occlusive coil pack.

Figure 3

(A) 79M. Fall. CT chest with contrast. Sternal fracture (red arrows). Left parasternal active extravasation of contrast/pseudoaneurysm (green arrow). (B) Chest CT. Coronal reconstruction. Left parasternal active extravasation of contrast (green arrow).

Figure 4

(A) Left internal mammary artery (LIMA) microcatheter DSA angiogram. Left parasternal active extravasation/pseudoaneurysm from side branch of LIMA (green arrow). (B) Microcatheter DSA LIMA post coil embolization. Coils are deposited as a bridge covering the side branch bleeding source, sometimes referred to as sandwich technique or “jailing technique”, to eliminate antegrade as well as any retrograde or collateral flow to the bleeding side branch. No further extravasation.