Angioplasty (percutaneous coronary intervention - PCI) Notes
This is also sometimes called PTCA - Percutaneous Transluminal Coronary Angioplasty
This procedure is able to open partially closed vessels before they become totally occluded. The patient is awake during the procedure. They may experience short periods of pain (explained below), but generally should not feel too uncomfortable. They may be given a sedative if they feel anxious.
***ANGIOPLASTY DOES NOT IMPROVE LONG TERM OUTCOME – it does not prolong life*** - it is purely for symptom relief. On the other hand, CABG does reduce MI related mortality, and can prolong life.
It is a coronary revascularisation technique – the other one of these being CABG.
Indications
- STEMI (ST elevation MI) acute coronary syndrome – PCI is the preferred treatment – it is preferred over THROMBOLYSIS – however, many centres don’t offer PCI, thus thrombolysis may be used instead. It can also be used in STEMI when thrombolysis is contra-indicated.
- Stable angina – should only be used in:
o Single or double vessel disease – i.e. disease only involving 1 or 2 of the coronary arteries
o Triple vessel disease who are not suitable for CABG
Procedure
This does not involve major surgery.
- A balloon tipped catheter is entered into the body. This commonly enters via the femoral artery, or radial artery (in the past, the brachial artery was also used, but this is now rare). the artery is opened with an introducer needle, and this part of the procedure is called percutaneous access. Normally, the patient has had some local anaesthetic, so that they cannot feel this process.
- Open access to this artery is gained, and a ‘sheath introducer’ essentially holds the artery open. Then a guiding catheter is placed in the artery, and passed all the way up to the opening of the coronary artery.
o This guiding catheter also sometimes allows for radiopaque dies to be passed through the coronary arteries to see where the larges section of narrowing is. Usually the dye used is iodine-based.
- There is then an x-ray to see the opaque dye. The cardiologist will then select an appropriately sized balloon tipped catheter for this particular patient. Heparin is given before the catheter is inserted.
- The balloon tipped catheter is then inserted and guided into place using x-ray, to the optimum position of the most occlusion of the artery. The balloon is inflated, and often a stent is placed in the artery.
o It can take 30-60 seconds to inflate the balloon. This process may occlude the coronary artery, and so for a short time, the patient may feel an angina type pain. They may be given opiates for this pain
o The stent is often on the outside of the balloon, and the stent is expanded by the pressure of the inflating balloon.
o The procedure may be repeated in several locations within the artery.
o A sedative may be given before the procedure if the patient feels anxious.
Factors to consider on an individual basis:
- Patients on warfarin or heparin may have to stop therapy 2-3 days before the treatment to prevent excessive bleeding from the femoral artery / site of catheter insertion. Obviously this does not apply to patients having this done as an emergency procedure!
- Patients may be asked not to eat for several hours before the procedure
- Insulin dependent diabetics may have to alter their insulin regimen on the day of treatment
The procedure lasts about 30 minutes. This is longer if more than one part of the artery is to be widened
Patients may need to stay in hospital overnight for observation following the procedure
Efficacy
- The treatment is 90% successful in reducing the severity of angina. However – it cannot be used for all people with angina – it is not suitable for those with lots of narrowed sections of artery.
- Over ¾ of patients have no ischaemic heart disease symptoms for several years afterwards (although the symptoms often return again later – in which case CABG may be required)
- Bloodflow through the affected artery is often increased 3-4x
Afterwards
- Patients should avoid any heavy activities (e.g. lifting or heavy exercise) for 1 week
- There will be a small wound at the site of entry of the catheter
- You should not drive for 1 week after the procedure
- Patients with an HGV liscence – will need to consult the DVLA about driving a bus or a lorry after having an angioplasty.
o Angina normally disqualifies drivers from driving HGV’s – however, 6 weeks after a PCI, the patient may take an ETT, and if they pass, then they may be allowed their licence back.
- Patient are often able to go home the same day, although they may be kept in for observation overnight
- Patients should take antiplatelet therapy:
o PCI in STEMI - Long term aspirin, and clopidogrel 75mg daily for 1 month
o PCI in stable angina – long term aspirin
Complications
- Bruising at the entry site
- Infection at the entry site (consult GP if the entry site becomes red and painful – they will probably get antibiotics)
- Failure to stretch the artery (1 in 20 cases) – these patients may instead be suitable for a coronary artery bypass graft. However, this is more serious, and thus it is probably best to try angioplasty first.
- Hypersensitivity to the dye
- Serious complications:
o Blockage of the coronary artery (1 in 100). These patients will be taken for emergency bypass surgery.
o MI – (less than 1%) – will require emergency CABG
o Damage to coronary artery by the catheter – less than 0.5%. treated surgically
o Stroke – 0.5%
o Death – 0.2%
o Regrowth of the atheroma over the stent – this occurs in 25-60% of cases. The chance of restenosis depends on other risk factors, such as diabetes. Newer stents are being developed that are coated with products that prevent the growth of atheroma. These are called drug eluting stents (DES). However, these are controversial, as although they halve the rate of plaque formation, they have a higher rate of stent failure, and they do not improve long term survival. The drugs they give off are basically anti-inflammatory. This also reduces normal healing after placing the stent, hence the reason why these patients need to be on clopidogrel for longer.
§ They are also more expensive, both in manufacture, and due to the longer dose of clopidogrel that they require.
o Cardiac tamponade – 0.5%
o Systemic bleeding – 0.5%
Compared to CABG – for stable angina
- PCI is less invasive and less costly
o However – in the long term these benefits are outweighed by the fact the treatment needs to be re-done.
- Recent evidence suggests that overall, PCI is less cost effective than CABG, although obviously, it needs to be assessed on a case by case basis
Compared to thrombolysis for acute coronary artery syndrome
- PCI has lower death rates, lower recurrent ischaemia, and fewer major complications in STEMI
- The evidence suggests it is generally more effective than thrombolysis
Finally – there is a variation of the procedure using an argon laser beam - and the laser is able to dissolve the plaque.
Notes by Tom Leach
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