Central venous catheter placement in the intrathoracic vein may cause potentially lethal complications in the form of an injury to the internal mammary artery. Hypotension during or immediately after the procedure should be a warning of a serious adverse event, such as massive hemothorax, that may compromise life. Adequate drainage of the pleural cavity may not completely relieve vascular compression if some of the bleeding from an injured internal mammary artery is extrapleural. Early diagnosis and treatment by selective embolization of the injured vessel in interventional radiology is the first therapeutic choice and may be life saving.