What procedure involves insertion of a device to hold open a vessel and is usually performed after vascular surgery?

The procedure you're referring to is known as angioplasty, often accompanied by the placement of a stent. During angioplasty, a catheter with a balloon is inserted into a narrowed or blocked blood vessel, which is then inflated to widen the vessel. A stent, a small mesh tube, is usually placed to keep the vessel open and maintain proper blood flow, particularly after vascular surgery. This procedure is commonly used to treat conditions like coronary artery disease.