Investigations and Interventions
- Angiography
- Angioplasty (PCI)
- Bypass Surgery (CABG)
- Cardiac Catheterization
- Echocardiogram
- Exercise Tolerance Test (ETT)
Angiography
Introduction
This is a technique used to visualise the inside of vessels, in this case, those of the heart.
It is basically
used to assess the extent of angina. It involves
cardiac catheterisation. Once the catheter is in place, an
iodine based dyeis injected into the coronary vessels, and the extent of narrowing (atheroma) can be asses by –x-ray.
- The angiogram is actually recorded as a moving picture as many low-dose x-rays are taken in quick succession.
Procedure
- The patient will lie flat on a couch, with the x-ray machine above them. The catheter will be passed to the opening of the cardiac vessels from the aorta.
- Patients may feel an occasional missed or extra heart beat during the procedure – this is normal.
- Basically – its exactly the same as catheterisation! – except that a bit of dye is squirted in and x-rays taken.
- The test normally lasts about 30 minutes.
Complications
- Mortality is about 1%
- May be some bruising at the entry site
- Some patients may have stitches at the entry site to seal it up
- May have a false aneurysm at the femoral artery if this was used as the entry site
- May get angina-type pain during the procedure
- May get an infection at the site of entry
- May have a warm flushing feeling when the dye is injected
- Stroke and MI are possible but rare
- Also rarely, the coronary artery may be damaged and emergency bypass may need to be performed
Angioplasty (PCI)
Angioplasty (percutaneous coronary intervention - PCI)
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:
- Single or double vessel disease – i.e. disease only involving 1 or 2 of the coronary arteries
- 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.
- This guiding catheter also sometimes allows for radio-opaque 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.
