Emergency angioplasty: the cardiologist's role
Tim Gilbert is consultant cardiologist at the Norfolk and Norwich University Hospital.
We do primary angioplasty under local anaesthetic, which means the patient is still conscious. That’s because the risks of general anaesthetic for someone who is having a heart attack are very high, and also because the procedure can be done perfectly well using a local.
In Brian’s case we did an angiogram, which showed he had a right coronary artery blocked by a blood clot, and a badly narrowed left coronary artery. In this situation, we insert a hollow tube called a catheter, either into the radial artery in the wrist or the femoral artery at the top of the leg.
First, I puncture the artery with a needle and pass a guide wire through the needle. Over the needle I insert a plastic tube called a sheath. Then through the sheath we insert a catheter, which passes to the coronary arteries and allows us to inject dye into the blood vessels so they can be seen on the X-ray screen.
I pass the catheter up the main blood vessel that runs parallel with the spine, and direct it into the right coronary artery. Using a small syringe, we inject the dye. Then we can see where the blood vessel narrows and the blood flow stops.
The blockage is now contained behind the stent and good blood flow is restored
I put a guide wire, which is just 14 thousandths of an inch wide, inside the catheter until it comes out at the other end. The guide wire is then fed down the artery and across the blockage into the blood vessel beyond. The area of disease in Brian’s artery was about 2cm long.
We put a smaller tube called a suction catheter inside the catheter over the guide wire, and use it like a vacuum cleaner to suck out the clot and other material that’s in there. Immediately you can see that the blood flow looks much better. You’re just left with a small narrowing of the blood vessel.
We then widen the artery using a balloon, often with a stent too. The stent is a tube of metal meshwork, and they come in different sizes so we can choose one that fits snugly against the artery wall. It’s mounted on a long tube called a balloon catheter. The stent starts off compressed so it’s only about 1mm in diameter.
Once the stent is exactly where we want it, we can gradually increase the pressure in the tube to inflate the balloon, a bit like using a bicycle pump. The stent expands to fill the blood vessel. The blockage is now contained behind the stent and good blood flow is restored.