PCI in stable angina: benefits, complications and outcome predictors
THE CONTEXT
Percutaneous coronary intervention (PCI) relieves symptoms of chronic stable angina. Its acute and long-term complications and the complexity of the target lesion influence outcomes.
Clinical role
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PCI often provides excellent symptom control and is as effective as anti-anginal drug therapy, but it does not reduce myocardial infarction (MI) or improve survival in chronic stable angina.
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PCI is mainly used in single- or two-vessel disease. Stenoses in native coronary arteries and bypass grafts can be dilated.
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PCI can provide palliative treatment for recurrent angina after coronary artery bypass grafting.
Acute complications
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Coronary occlusion by thrombus or an intimal flap from coronary dissection can cause MI. This occurs in about 2% of procedures.
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Further intervention can often correct acute occlusion, although emergency coronary artery bypass grafting is occasionally required.
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Mild myocardial damage, indicated by elevated cardiac troponin, occurs in up to 25% of cases.
Restenosis and recurrent symptoms
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Restenosis is the main long-term complication, occurring in up to one-fifth of cases. Elastic recoil and smooth muscle proliferation contribute, usually within 3–6 months.
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Stenting substantially reduces restenosis, probably by allowing more complete dilatation.
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Slow release of antiproliferative drugs such as sirolimus or paclitaxel from stent coatings reduces neo-intimal hyperplasia and in-stent restenosis.
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Recurrent angina affects up to 5%–10% of patients at six months and may require further PCI or bypass grafting.
Factors influencing success
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Procedural success and complications depend on disease complexity, operator experience and important comorbidities such as diabetes and peripheral arterial disease.
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A good outcome is less likely with a complex, long, eccentric or calcified lesion; a lesion on a bend or within a tortuous vessel; branch involvement; or thrombus.