Unstable angina is defined as recurrent episodes of angina on minimal effort or at rest. It may be the initial presentation of ischaemic heart disease, or it may represent the abrupt deterioration of a previously stable anginal syndrome.
Unstable angina is also described as crescendo angina, pre-infarction angina, and intermediate chest pain syndrome.
Unstable angina is one of the possible presentations of acute coronary syndrome:
acute coronary syndrome (ACS) encompasses previous terms such as non-Q wave myocardial infarction and unstable angina
- ACS is defined as: (1)
- unstable angina (symptoms at rest with ECG changes)
- Non STEMI (non ST elevation myocardial infarction) with at least two of the following criteria
- symptoms at rest
- raised serum Troponin
- ECG changes
- STEMI (ST elevation myocardial infarction) symptoms with ST elevation on ECG
Unstable angina is provoked more easily and persists for longer than stable angina.
A study investigating one-year mortality following diagnosis of acute coronary syndrome showed (2):
- mortality rate was 3.9% within one year of discharge
- independent mortality predictors identified (in order of predictive strength):
- age, lower ejection fraction, poorer EQ-5D quality of life, elevated serum creatinine, in-hospital cardiac complications, chronic obstructive pulmonary disease, elevated blood glucose, male gender, no PCI/CABG after NSTEMI, low haemoglobin, peripheral artery disease, on diuretics at discharge
A study investigating two-year mortality following diagnosis of acute coronary syndrome showed (3):
- mortality rate was 5.5% within two years of discharge
- independent mortality predictors identified were:
- age, low ejection fraction, no coronary revascularization/thrombolysis, elevated serum creatinine, poor EQ-5D score, low haemoglobin, previous cardiac or chronic obstructive pulmonary disease, elevated blood glucose, on diuretics or an aldosterone inhibitor at discharge, male sex, low educational level, in-hospital cardiac complications, low body mass index, ST-segment elevation myocardial infarction diagnosis, and Killip class
Data from a large Swedish registry including 108 315 post-MI patients with long-term follow-up revealed a cumulative rate of a cardiovascular composite endpoint (cardiovascular death, recurrent MI, and stroke) of 18.3% in the first year after MI, 9.0% in the subsequent year and 20.0% in the following 3 years (4)
References:
- Acute coronary syndrome. Scottish Intercollegiate Guidelines Network - SIGN (2016)
- Pocock S et al. Eur Heart J Acute Cardiovasc Care. 2015 Dec; 4(6):509-17. Epub 2014 Oct 9.
- Pocock SJ et al. Predicting two-year mortality from discharge after acute coronary syndrome: An internationally-based risk score. Eur Heart J Acute Cardiovasc Care. 2019 Dec; 8(8):727-737. Epub 2017 Aug 4.
- Jernberg T et al. Cardiovascular risk in post-myocardial infarction patients: nationwide real world data demonstrate the importance of a long-term perspective. Eur Heart J. 2015;36:1163-1170