Percutaneous Coronary Intervention (PCI)

Synonyms: percutaneous transluminal coronary angioplasty (PTCA)

This is one of the two coronary revascularisation techniques currently used in the treatment of ischaemic heart disease¹, the other being coronary artery bypass grafting (CABG).

PCI involves nonsurgical widening of the coronary artery, using a balloon catheter to dilate the artery from within. A metallic stent is usually placed in the artery after dilatation. Antiplatelet agents are also used. Stents may be either bare metal or drug eluting stents.

• ST segment elevation acute coronary syndrome² (ST segment elevation myocardial infarction or STEMI)
  • As immediate treatment - PCI, if available, is preferred over thrombolysis; it should also be used when thrombolysis is contraindicated.
  • As rescue treatment in patients treated by thrombolysis - if there is failure to reperfuse, consider PCI within 12 hours of thrombolysis.
  • As early intervention - patients treated with thrombolysis should be considered for early (within 24 hours) angiography and revascularisation.
  Currently, PCI is not available in all centres or around the clock. SIGN recommends developing local protocols for STEMI, including the emergency transfer of patients for PCI.
• Acute coronary syndrome without ST elevation³ (unstable angina and non-ST elevation myocardial infarction).
  • High risk patients - consider angiography and appropriate revascularisation during the initial hospital admission.
• Stable Angina¹
  PCI should be offered to:¹
  • Patients with single or double vessel disease, where optimal medical therapy fails to control symptoms.
  • Patients with triple vessel disease, who are unsuitable for CABG.

• PCI should be done by experienced, high volume operators and institutions (>75 and >400 procedures/year respectively).
• No anaesthetic is needed, though patients may be given a sedative. Patients can usually mobilise a few hours afterwards, and go home the same or next day.
• The technique involves gaining arterial access via the femoral, radial or brachial arteries. Under fluoroscopy, a guidewire is passed into the coronary artery and across the stenosis; the ballon or stent catheter passed over it, and the lesion dilated and/or stented. Glycoprotein IIb/IIIa inhibitors are given in high risk procedures, and opiates may be used if angina occurs during angioplasty.

Antiplatelet drug treatment following PCI

Current recommendations are:

• PCI for acute coronary syndrome - longterm aspirin plus clopidogrel 75mg daily for one month.²
• PCI for stable angina - longterm aspirin.¹
• Drug eluting stents - longterm aspirin plus clopidogrel 75 mg daily for 12 months, possibly longer, or as advised by cardiologist.⁵

Driving⁷

UK DVLA rules for private motor cars:

• Angina - drivers must stop driving when symptoms occur at the wheel
• After angioplasty, drivers must not drive for 1 week, after this they can recommence driving if there is no other disqualification (but remember that after MI driving must cease for 4 weeks)

UK DVLA rules for lorry or bus drivers:

• Angina disqualifies from driving
• After PCI at least 6 weeks must elapse, then relicensing may be allowed after satisfactory exercise test

Major complications are uncommon, but include: death (0.2% but higher in high risk cases), acute myocardial infarction (1%) which may require emergency CABG, stroke (0.5%), cardiac tamponade (0.5%) and systemic bleeding (0.5%).

Minor complications are: allergy to the contrast medium, nephropathy, and complications at the access site such as bleeding and haematoma.

Restenosis is the "Achilles heel" of PCI , and occurs in 25-60% of stents. The restenosis rate depends mainly on characteristics of the target stenosis, but also on co-morbidity such as diabetes. Restenosis may be asymptomatic, but can cause acute symptoms or require repeat revascularisation.

Stable angina^1,8

Compared to CABG, PCI is less invasive and initially less costly. These advantages are eroded in the longer term by the need for repeat revascularisation.

Individual treatment recommendations will depend on the site and nature of the stenosis and the patient's clinical condition, but broad guidelines are:

• PCI is the recommended treatment for single or double vessel disease, and is an option for isolated LAD stenosis.
• CABG gives a better prognosis for left mainstem and triple vessel disease; it may also be more effective for isolated LAD stenosis.
• Recent evidence suggests that overall, PCI is less cost effective than medical treatment or CABG.
• Patients should be informed and involved in treatment decisions.

Minimally invasive CABG is a developing field, and may shift the balance in favour of surgery rather than PCI.

Acute coronary syndrome

• ST elevation acute coronary syndrome: Compared with thrombolysis, PCI reduces death rates, recurrent ischaemia and major complications, with NNTs of 9-50.²
• Non ST elevation acute coronary syndrome: current evidence is conflicting, regarding PCI versus optimum medical management. Current guidelines suggest PCI tor patients classified as "high risk" in this situation.³

Drug eluting stents (DES) are controversial. They were initially hailed as breakthrough technology, because they halved the rates of restenosis after PCI.⁵ However, recent evidence suggests that DES are no better than bare metal stents in terms of longterm survival, and they may be associated with late stent failure, which can cause death or acute MI. They may also increase the risk of noncardiac death - it is not clear why.⁹

How do DES work? They aim to reduce restenosis, by targeting the scar tissue formation that causes it. To this end, the stents are coated with drugs which are immunosuppressant, antimitotic or anti-inflammatory.¹⁰ However, these drugs also delay healing of the vascular endothelium which is damaged by PCI, hence they may increase the risk of thrombosis. Patients with DES are therefore given prolonged treatment with clopidogrel (current advice is for one year, possibly longer).⁵

DES were licenced quickly after trials on low risk patients; they have since been widely used off-licence in higher risk groups, with higher complication rates - resulting in USA FDA warnings about their use.¹¹

DES have also been criticized as expensive, due both to the cost of the actual stent, and the longer clopidogrel therapy which they require.⁸