PCI or stent procedure - an explanation
A percutaneous coronary intervention starts with an angiogram. During an angiogram, x-ray pictures are made of the heart arteries. The procedure can be performed from the artery at the top of the leg (femoral artery) or in the wrist (radial artery) and is performed under local anaesthetic. A long thin tube (called a catheter) is guided under x-ray imaging control until its tip reaches the arteries around the heart (the coronary arteries).
Dye is injected into the coronary arteries so that any narrowings can be identified using x-ray. In the PCI procedure, a very thin wire is guided under x-ray image control, across the narrowed part of the coronary artery.
Once in place, a balloon is passed over this wire into the narrowed segment. Inflating the balloon squashes the blockage (made of fatty tissue and sometimes clot) out of the way and widens the artery. A stent (a small metal mesh in the shape of a tube) is usually then implanted to keep the artery open. The stent is supplied crimped over a balloon, which is used to deploy it against the inner wall of the artery. As the balloon inflates, the stent is expanded, pressing out against the arterial wall, so helping to hold open the newly widened artery. The balloon is then deflated and withdrawn, leaving the stent in place.
Following a PCI, most patients return home the next day, though some patients can be treated and discharged the same day. Patients admitted following a heart attack usually remain in hospital for longer (on average 3 days). Generally, PCI is a very safe treatment but complications can occur around the time of the procedure or weeks or months later.
Potential adverse events during hospital stay
PCI procedures are occasionally associated with adverse outcomes, and the most severe of these are called ‘Major Adverse Cardiac and Cerebrovascular Events’ (MACCE). These include events such as stroke, heart attack, need for emergency coronary bypass surgery or death. While some of these adverse events may be complications of the PCI procedure itself, most are not, and instead are a result of the heart disease itself. A more detailed explanation is given below.
Potential complications after discharge
After PCI, the symptoms of angina are usually much improved. There follows a period when the walls of the newly stretched arteries heal.
In the past metal stents without a coating were often used. Cells used to grow around the stent and form a new lining. If the healing process was over exuberant this led to re-narrowing of the artery (so called ‘restenosis’), and a recurrence of angina.
Many current stents are coated in a drug to reduce the chances of re-narrowing of the artery. This drug passes into the wall of the artery reducing the proliferation of cells around the stented site. This means that the likelihood of recurrent symptoms in the first few months is much lower.
There is a small risk (less than 1 % per year) of the treated vessel blocking abruptly, usually due to clot formation.
|List of abbreviations|
|ACS||Acute Coronary Syndrome|
|BCIS||British Cardiovascular Intervention Society|
|CABG||Coronary Artery Bypass Grafting|
|CHD||Coronary Heart Disease|
|MACCE||Major Adverse Cardiovascular and Cerebrovascular Event|
|NSTEMI||Non ST elevation Myocardial Infarction|
|PCI||Percutaneous Coronary Intervention|
|STEMI||ST elevation Myocardial Infarction|
Analysis of PCI operator outcomes
Individual operator outcomes from performing PCI