Coronary stents

Coronary stents are implanted during minimally invasive PCI procedures treating narrowed coronary arteries, which supply Oxygen to the heart muscle. Stainless steel and cobalt chrome alloys have the plastic properties that enable balloon-expandable stents to withstand the high-pressure present in these small blood vessels. Balloon-expandable stents undergo plastic deformation during balloon-expansion thereby fixing their shape.

In cases of perforation or significant damage to the arterial wall, special stents coated with pericardium tissue can be applied as an emergency measure to “seal” the damaged area and enable blood flow through the artery.

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Coronary stents

Neurovascular stents

The two most common types of cerebrovascular disease are ischemic stroke (87%) caused by a blocked or narrowed intracranial blood vessel and hemorrhagic stroke (10%) often caused by a ruptured aneurysm.

Tiny self-expandable stents can be used to re-open blocked brain blood vessels. On the other hand, stent-assisted coil embolization treats intracranial aneurysm by threading a thin wire (embolic coil) through a catheter into the affected area of the brain in order to fill the weakened portion of the vessel.

Balloon-expanded stents require high pressure for their expansion which can damage the thin blood vessels of the brain. Self-expanding stents eliminate the need for high pressure expansion making Nitinol the metal of choice for neurovascular stents.

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Neurovascular stents

Carotid stents

A self-expandable Nitinol stent is fitted inside a narrowed carotid artery, which feeds blood to the brain, to improve blood flow and prevent the artery from collapsing or closing after the procedure.

Carotid stents need to be elastic because of the perceived risk that outside pressure on a balloon-expandable stent (stainless steel or cobalt chrome) may permanently damage the stent and block the artery.

Self-expanding stents eliminate the need for high pressure expansion making Nitinol the metal of choice for neurovascular stents.

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Peripheral stents

Peripheral stents are often self-expandable Nitinol stents that can be bare metal, drug coated, or membrane coated.

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Biliary stents

Biliary stents are used to treat obstructions in the bile duct. The complex delivery and positioning of biliary stents requires high flexibility to allow maneuverability through loops, curvatures and angulated anatomies.

Biliary stent design takes into account flexibility, migration resistance and radial pressure requirements.

STI manufactures the metal stent, typically made of Nitinol, and welds radiopaque markers as needed.

A membrane cover is added later to prevent in-growth and ensure free passage through these relatively long (≤ 120 mm) stents.

Read more about the Stent manufacturing process.