Right Internal Mammary Artery Perforation and Large Mediastinal Hematoma Formation as a Complication of Radial Access Coronary Angiography: A Case Report

Perforation of the right internal mammary artery (RIMA) is an extremely rare vascular complication associated with the transradial approach (TRA) to coronary angiography. A 75-year-old woman presented with weakness. ECG revealed atrial fibrillation with long pauses. Echocardiography showed severe left ventricular (LV) systolic dysfunction (LVEF: 20%). During coronary angiography, an unintended passage of a hydrophilic wire into the RIMA caused tissue staining indicative of severe spasm without perforation. The patient was initially managed conservatively, but then she experienced a significant drop in hemoglobin. Subsequent CT angiography revealed a mediastinal hematoma. The patient was emergently transferred to the catheterization laboratory, where angiography confirmed RIMA perforation with dye extravasation. Despite the unsuccessful balloon tamponade, a 2.5 × 21 mm covered stent was deployed, successfully sealing the perforation. This case is distinctive as one of the very few reported RIMA perforations complicating TRA coronary angiography. It emphasizes the importance of vigilance even when early angiography shows no clear perforation and highlights covered stenting as a life-saving option when balloon tamponade is unsuccessful. Knowing the possible complications of the TRA, specifically during hydrophilic guidewire maneuvers, empowers us to recognize and manage these complications promptly.