How Doctors Implant a Permanent Stent Using a Balloon

This patent describes the method for placing a permanent, expandable wire mesh tube inside a blood vessel or other body tube using a balloon-tipped catheter to widen it and keep it open.

What it covers

This patent describes a method for implanting a medical device, called a prosthesis or intraluminal graft, inside a body passageway like a blood vessel. First, the prosthesis is placed onto a catheter (Claim 1). The catheter and prosthesis are then inserted into the body passageway (Claim 1). Once at the desired location, a part of the catheter, specifically an inflatable balloon (Claim 3), is expanded. This expansion forces the prosthesis outward, permanently deforming it beyond its elastic limit (Claim 1) to contact the walls of the passageway. The prosthesis, often a wire mesh tube made of tantalum (Claims 4, 5), then remains in place to prevent the passageway from collapsing (Claim 7). After expansion, the balloon is deflated, and the catheter is removed (Claim 2). For example, this method can be used to open a narrowed artery and keep it wide.

What it doesn't cover

• —Grafts that expand on their own without needing a balloon or other external force from the catheter.
• —Grafts that are not permanently deformed when expanded, meaning they would spring back to their original size.
• —Methods where the graft is expanded by a mechanism other than an inflatable portion of the catheter.
• —Grafts that are not delivered upon a catheter but are instead injected or deployed differently.
• —Grafts that are not tubular or made of intersecting elongate members, as described in Claim 13.

The clever bit

The key innovation was the idea of a graft that could be delivered in a collapsed state, then permanently expanded in situ by a balloon to a size determined by the body passageway, and critically, would stay expanded due to plastic deformation. This ensured the graft wouldn't migrate and would keep the vessel open.

Why it matters

This patent is a cornerstone for modern interventional cardiology, specifically for balloon-expandable stents. It provided the fundamental method and device concept that allowed doctors to treat blocked arteries without major open surgery. The technology described here enabled the widespread adoption of coronary stenting, significantly improving outcomes for patients with heart disease.

Real-world examples

• 1.Palmaz-Schatz stent
• 2.Balloon-expandable coronary stents
• 3.Balloon-expandable peripheral stents
• 4.Balloon-expandable vascular grafts