- Venous Sinus Stenting (experimental): Venous sinus stenting is the experimental procedure being tested in this protocol and consists of placing a stent into the narrowed veins of the brain. The participants will be placed under general anesthesia because it is important that you do not move at all during the procedure. A catheter will be inserted through the upper part of the leg (groin area) and guided through the veins all the way to neck. Then, a balloon will be advanced through the catheter and positioned across the stenosis. The balloon will be carefully inflated for a few seconds. This process is called angioplasty and will partially re-open the narrowing, making placement of the stent easier. The balloon will be removed and then the stent will be advanced through the catheter in neck across the stenosis and carefully deployed.