How heart stents are made

A heart stent starts as a thin metal tube, and a laser cuts it into a mesh that can collapse and then expand.

stations: 6
things upstream: 29
raw sources: 15
steps from the ground: 6

The short version

A coronary stent is a small mesh tube that props open a heart artery. Most current ones use a cobalt-chromium or platinum-chromium alloy. A laser cuts the mesh from thin-walled tubing, electropolishing smooths the struts, and a coating of drug is added. The stent is collapsed onto a balloon catheter, which later expands it in place, then packaged and sterilized.

Draw the alloy tubing

Stents start as thin-walled tubes of high-quality alloy. Current drug-eluting stents use cobalt-chromium or platinum-chromium, and stainless steel is the older choice.

Goes in
Cobalt Chromium
Laser-cut the mesh

A fiber laser in a tube cutting system traces the pattern of struts around the tube, leaving a fine metal grid. That grid is what lets the stent be small on the way in and wide once in place.
Electropolish the struts

The cut stent goes into an electrolytic acid solution, and electric current strips metal from its surface. This takes off the rough edges from cutting, since a rough surface in a blood vessel can promote clotting.
Coat with a drug layer

A coating of limus-family drug such as everolimus or zotarolimus goes on the struts, often held in a polymer that controls its release into the artery wall. Some designs use no polymer.
Crimp onto the balloon

The stent is collapsed over the deflated balloon at the tip of a catheter. In this state it is small enough to pass through narrowed arteries.
Pack and sterilize

The stent and its catheter are sealed in a sterile package and sterilized before shipping.

End of the lineHeart stent

Worth repeating

The word stent comes from Charles Stent, an English dentist who improved denture-making in the 19th century.
Coronary stenting began in 1986 with Jacques Puel and Ulrich Sigwart.
As of 2023, drug-eluting stents were used in more than 90 percent of procedures to open blocked heart arteries.