A guiding catheter, which is a long plastic tube, is passed from an artery in the groin or the wrist to the coronary artery, under local anaesthetic. A fine guidewire is passed through the guiding catheter and advanced into the coronary artery under x-ray control. Once the guidewire has crossed the narrowing and is in the artery beyond, a balloon catheter is tracked over the wire and into the narrowing. Once the deflated balloon is in place across the narrowing, it is inflated to stretch that part of the artery open; the balloon is then deflated and removed, leaving the guidewire in place. A stent mounted on another deflated balloon is positioned across the narrowing, and the balloon is inflated to expand the stent and artery. The balloon is deflated and removed leaving the expanded stent in place. Once expanded the stent cannot move.
|Right coronary artery pre- and post-stenting|
PCI, like angiography, is carried out under light sedation and with local anaesthetic, but PCI usually takes a bit longer to perform than angiography. Most people do no feel any sensation after the injection of local anaesthetic into the groin or wrist. Movement of the catheters inside the arteries is not painful and usually there is no sensation at all, but there may be some angina-like discomfort during inflation of the balloon. Significant pain is very uncommon.
Admission for PCI will be arranged by the office staff of Mercy Angiography. Admission is usually two hours before PCI, and while patients should not eat during the four hours before angioplasty, they may drink water until admission. You should take your usual medication including aspirin at your usual times with a small glass of water. (Note: aspirin is an important medication in PCI because of its antiplatelet activity "blood thinning". All patients should be on aspirin unless there is definite allergy to it, or some other important contraindication). The nursing staff and the interventional cardiologist should be informed if the patient is not taking aspirin for any reason. Dosing and timing of insulin may also need to be discussed for diabetic patients.
Most patients stay overnight following PCI, but same day discharge may be possible if it is done early in the day. The introducer sheath is removed from the artery in the wrist immediately following PCI; the sheath from the groin artery may stay in for a little longer to allow the effect of anticoagulant drugs ("blood thinning") like heparin to wear off. Those done via the groin need a period of bed rest to ensure that there is no bleeding from the puncture site.
Angioplasty causes localised injury to the artery, which sets up a healing response a bit like a scar developing on the skin after an injury. If too much "scar tissue" forms on the inside of the artery it can renarrow with a recurrence of the previous symptoms of angina. This is known as restenosis: stents reduce the chance of restenosis at the angioplasty site compared with ballooning alone, but it can still occur as cells grow through the mesh of the stent. It is most common between six weeks and six months after stenting, but is very rare beyond six months. It is more likely to occur in small diameter vessels, long narrowings and in diabetic patients. If it does occur, it is usually possible to treat the artery again by angioplasty.
Drug-eluting stents are coated with a medication to reduce the chance of restenosis and the need for repeat treatment. Simple narrowings with a low chance of restenosis can still be effectively treated with conventional stents.
It is important to realise that PCI does not "cure" the underlying condition, and continuing treatment with medication will still be required. Patients should take aspirin indefinitely, and will also require clopidogrel (another antiplatelet drug) for a period of time to prevent the development of blood clot on the stent while it is healing into place. Lifelong treatment to lower cholesterol level and control blood pressure (to try to slow down the underlying narrowing process) will often be required as well.
Address: 98 Mountain Rd, Epsom, Auckland.
Phone: 09 630 1961
Facsimile: 09 630 1962
Website: Mercy Angiography