Untangling a Knotted Angiographic Catheter Using a Balloon Catheter: A Case Report.

When a 66-year-old man with hepatocellular carcinoma underwent an angiographic examination, a 4-Fr catheter was inserted from the right femoral artery. It became tightly knotted in the descending aorta. To untangle the knotted catheter, a noncompliant balloon catheter was delivered into the knotted loop from the contralateral femoral artery. After the balloon catheter was inflated from the inside of the knotted loop, the knot became loose. Finally, the knotted catheter was untangled. Subsequently, the remainder of the examination was performed as initially planned.