Balloon, then scaffold
Percutaneous coronary intervention — usually shortened to PCI — is the whole family of catheter-based treatments that open a narrowed coronary artery. The first and oldest member is balloon angioplasty. A guidewire thinner than a hair is steered across the blockage, and a deflated balloon rides over that wire to the exact spot. When the balloon is inflated, it presses the plaque outward against the vessel wall, widening the channel so blood can flow again.
Balloon alone had a problem: arteries are elastic, so once the balloon came out, the vessel often sprang partly shut again, and sometimes a torn flap could close it abruptly. The fix was the coronary stent — a tiny, expandable tube of metal mesh. The stent is crimped onto the balloon; when the balloon inflates, the mesh locks open against the wall, and the balloon is withdrawn leaving the scaffold behind. It is like propping open a collapsing tunnel with a permanent metal frame.
Even bare metal stents had a flaw: the body sometimes grew scar tissue through the mesh, re-narrowing the spot within months. The modern answer is the drug-eluting stent, whose surface is coated with a medicine that slowly releases to calm that overgrowth. Drug-eluting stents dramatically cut re-narrowing and are now the standard. Each generation solved the problem the last one left behind — a nice example of medicine improving by iteration.
Why minutes matter in a heart attack
PCI is sometimes a planned, calm procedure for stable symptoms. But its most urgent use is in a STEMI — the most severe kind of heart attack, where a coronary artery is completely and suddenly blocked by a clot. Downstream muscle is dying minute by minute from lack of oxygen. Here PCI becomes emergency reperfusion: rush the patient to the catheter lab, cross the clot, and reopen the vessel as fast as possible.
After a stent goes in, the new metal surface needs time for the body's own lining to grow over it smoothly. Until then, blood is prone to clot on it. So patients take two antiplatelet medicines together — usually aspirin plus a partner like clopidogrel — for a set period. This “dual antiplatelet therapy” keeps the fresh stent clear while it heals. Stopping it too early is genuinely risky, which is why this is one prescription doctors stress patients must not skip.