Coronary heart disease (CHD) is the leading cause of death in the UK. The main symptoms of CHD are angina (chest pain), myocardial infarction (heart attack) and heart failure. The National Institute for Health and Care Excellence (NICE) has published a series of formal guidelines for how to manage these conditions.
To determine whether a heart attack has occurred, an electrocardiogram (ECG) and blood test are carried out. If a myocardial infarction is confirmed, analysis of the ECG will lead to two possible diagnoses: ST-elevation myocardial infarction (STEMI) or non-ST elevation myocardial infarction (nSTEMI). This distinction is important since the guidelines vary for the management of these conditions.
Here we look at data from the Myocardial Ischaemia National Audit Project to understand whether heart attack patients are receiving the recommended treatment within the timeframes set out in the NICE Quality Standards.
For patients with STEMI, primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy (reopening of blocked coronary artery). This is carried out as an emergency treatment, which must be performed as soon as possible after diagnosis to prevent, or reduce, damage to heart muscle and subsequent heart failure. The target is to provide primary PCI within 90 minutes of a patient's arrival at hospital (door to balloon, or DtB) and within 150 minutes of a patient's call for help (call to balloon, or CtB).
Between 2004/05 and 2013/14 there was a significant increase in the proportion of STEMI patients receiving primary PCI within 90 minutes of arrival at a heart attack centre, from 52% to 92%. Since then, there has been a slight decrease to 89% in 2016/17. Overall, the median DtB time in 2016/17 was 40 minutes in England, 43 minutes in Wales and 31 minutes in Northern Ireland (data not shown).
Meanwhile, the percentage of patients treated within 150 minutes of calling for help fell from 75% in 2015/16 to 72% in 2016/17 (data not shown). The maintenance of in-hospital performance together with an increase in CtB time suggests that increasing delays to treatment are being incurred prior to the patient arriving at the heart attack centre. NHS England has proposed a target for CtB, which states that, by 2020, 90% of eligible heart attack patients should receive primary PCI within 150 minutes of calling for help.
Patients with nSTEMI (who lack the ST elevation on an ECG that is demonstrative of a complete occlusion of a coronary artery) generally do not require urgent reperfusion therapy. With adequate monitoring and drug treatments their symptoms often improve. However, diagnostic coronary angiography is recommended within 72 hours of first admission to hospital in order to gauge the extent of coronary disease. Follow-on PCI can be performed at the time of the angiogram, if necessary.
Recorded delays from admission to angiography for nSTEMI patients have not improved over time. In 2016/17, 19.3% of patients with nSTEMI who underwent angiography did so within 24 hours, 56.1% within 72 hours and 68.8% within 96 hours. This compares with 21% within 24 hours, 55% within 72 hours and 67% within 96 hours in 2010/11. This demonstrates an area for significant quality improvement.
Recognising the need to improve this aspect of care, NHS England introduced a Best Practice Tariff metric for 2016/17, through which participating hospitals receive a higher reimbursement where at least 60% of all nSTEMI patients receive angiography within 72 hours.
About this data
These indicators use data from the Myocardial Ischaemia National Audit Project. For more information, please see their audit reports.