There are three management options for patients with coronary heart disease (CHD):
- Medical therapy and risk factor modification: this is the main option for stable, low-risk patients and should be given to all patients with CHD. See separate Cardiovascular Risk Assessment and Cardiac Rehabilitation articles. In low-risk patients with stable coronary artery disease, aggressive lipid-lowering therapy is at least as effective as angioplasty in reducing the incidence of ischaemic events.
- Coronary artery bypass graft (CABG) surgery: this has been shown to produce better survival rates compared with medical therapy in certain patient groups. See separate Coronary Artery Bypass Grafting article.
- Percutaneous coronary intervention (PCI): this is generally for patients with isolated coronary artery disease. See separate Percutaneous Coronary Intervention article.
Coronary revascularisation is not without risks; thus, determining the risk/benefits prior to revascularisation is important. Risk assessment is undertaken using scoring systems. There are a number of various scoring models - for example:
- The Ontario scoring system: designed to assess the urgency of intervention. The three main urgency determinants are severity and stability of symptoms of angina, coronary anatomy from angiographic studies, and results of non-invasive tests for risk of ischaemia.
- The European System for Cardiac Operative Risk Evaluation (EuroSCORE): the EuroSCORE is a similar European system for cardiac operative risk evaluation based on a large database. It can be used to predict the risk of revascularisation regardless of whether surgery or PCI is considered.
- The SYNTAX score: predicts the risks associated with PCI, thus stratifying patients into those who are most likely to have adverse effects. Other scoring systems for PCI include the National Cardiovascular Database Registry (NCDR) CathPCI risk score.
- The Society of Thoracic Surgeons score and Age, Creatinine and Ejection Fraction score: these are both used to determine surgical risk.
A number of important factors influence the likely balance of risks and benefits. These include:
- Smoking: this is associated with poorer long-term survival after CABG. Those who stop smoking are less likely to undergo repeat surgery or to have a heart attack.
- Diabetes mellitus: patients have poorer long-term survival after revascularisation and a higher risk of re-stenosis. Good control of diabetes and hypertension reduces the rate of progression of vascular disease.
- Impaired left ventricular function: despite a higher operative mortality, they also obtain greater long-term survival benefit from revascularisation than people without impaired left ventricular function.
- Advanced age: the procedure-associated risk rises rapidly with age.
- Gender: women may have a higher procedure-associated mortality compared with men.
- Recent myocardial infarction or episode of unstable angina: recent coronary events increase procedural risk.
- Unfavourable coronary anatomy: extensive disease in the distal parts of coronary arteries reduces the likely benefits of intervention.
- Results of pre-intervention tests: eg, myocardial perfusion scanning or cardiac MRI.
- Presence of chronic kidney disease: CABG is superior to PCI where the eGFR is between 30-90 mL/min/1.73 m2. In severe chronic kidney disease and end-stage kidney disease or haemodialysis there is no such evidence and thus deciding between CABG and PCI is based on the individual patient.
Any decision should be made within a multidisciplinary team and patients should take an active role in the decision-making process. Obviously this may not be possible in the acutely unwell patient.
Revascularisation in stable disease or silent ischaemia
This is required when:
- The patient has persisting symptoms (medical therapy should be optimised); and/or
- Anatomical disease which, if intervened upon, will improve prognosis - eg, left main stem disease or proximal left anterior descending artery disease or a large area of ischaemia.
In this group, revascularisation is undertaken usually for both symptomatic relief and improvement in outcomes. This is the largest group of patients requiring PCI but the prognosis is very variable and, as such, scoring systems are also used in acute coronary syndrome to determine the risk:benefit ratio. The European Society of Cardiology recommend the use of the Global Registry of Acute Coronary Events score (GRACE score) in acute coronary syndrome patients. This determines the long-term risks and helps decisions regarding which patient should undergo invasive PCI. The GRACE score is discussed more fully in the separate Acute Coronary Syndrome article.
Patients with ongoing chest pain and ongoing ischaemia on the ECG may need urgent PCI (within two hours). Those with a very high GRACE score (>140), recurrent symptoms or significant inducible ischaemia on stress testing should have PCI. If the GRACE score is >140, PCI should be undertaken within 24 hours. Patients with lower scores should have PCI within 72 hours, usually as part of their inpatient stay.
Clinical Editor's comments (October 2017)
Dr Hayley Willacy recently read an interesting meta-analysis dealing with the treatment of people aged over 75 years who have non ST-elevation acute cornary syndrome(NSTEACS). NICE recommends treating NSTEACS either with stents or with medication depending on the person’s risk. These treatments are quite commonly used in younger people, but older people are less likely to receive them. Their results suggest that routine invasive therapy for people aged over 75 with non-ST-elevation acute coronary syndromes reduced the risk of dying, having a heart attack or stroke, and need for further intervention. However, there was a higher risk of major bleeding compared to treating people with medication and the authors suggest greater clarity is needed around the balance of risks and benefits for this group of people.
Revascularisation in ST-segment elevation myocardial infarction
Primary PCI in dedicated centres should be undertaken if possible in ST-segment elevation myocardial infarction. If this cannot occur within 120 minutes of the ECG diagnosis then immediate fibrinolysis should be performed and if this is successful, PCI should be undertaken within 24 hours. If, however, fibrinolysis is unsuccessful then rescue PCI will be required immediately.
Further reading and references
2014 ESC/EACTS Guidelines on myocardial revascularization; The Task Force on Myocardial Revascularization of the European Society of Cardiology and the European Association for Cardio-Thoracic Surgery (Aug 2014)
Mikhail GW; Coronary revascularisation in women. Heart. 2006 May92 Suppl 3:iii19-23.
Unstable angina and NSTEMI; NICE Clinical Guideline (March 2010 - last updated November 2013)
Roffi M, Patrono C, Collet JP, et al; 2015 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation: Task Force for the Management of Acute Coronary Syndromes in Patients Presenting without Persistent ST-Segment Elevation of the European Society of Cardiology (ESC). Eur Heart J. 2016 Jan 1437(3):267-315. doi: 10.1093/eurheartj/ehv320. Epub 2015 Aug 29.
Gnanenthiran SR, Kritharides L, D'Souza M, et al; Revascularisation compared with initial medical therapy for non-ST-elevation acute coronary syndromes in the elderly: a meta-analysis. Heart. 2017 Jun 16. pii: heartjnl-2017-311233. doi: 10.1136/heartjnl-2017-311233.