Shared learning database

 
Organisation:
University Hospital Lewisham
Published date:
January 2012

In patients presenting with stable chest pain with low to intermediate predicted risk of coronary artery disease, CT coronary angiography leads to more accurate detection of coronary artery disease, fewer second-line investigations and more definitive rule out of coronary artery disease with lower cost to reach diagnosis compared with exercise tolerance testing.

Guidance the shared learning relates to:
Does the example relate to a general implementation of all NICE guidance?
No
Does the example relate to a specific implementation of a specific piece of NICE guidance?
Yes

Example

Aims and objectives

NICE guideline 95 proposes using CT coronary angiography (CTCA) in patients at low predicted risk of coronary artery disease only. We designed this audit to compare the performance of CT coronary angiography versus exercise tolerance testing (ETT) in patients presenting with stable chest pain and low AND intermediate predicted risk of coronary artery disease. To determine whether CT coronary angiography can outperform exercise tolerance testing in patients presenting with stable chest pain at higher predicted risk of coronary artery disease (i.e. not just low risk, as recommended by NICE clinical guideline 95, but also intermediate risk).

Reasons for implementing your project

In most hospitals, exercise tolerance testing (ETT) has been and remains the preferred first-line investigation for patients presenting with stable chest pain. NICE clinical guideline 95 proposes using CT coronary angiography (CTCA) as first-line investigation in patients at low predicted risk only. Our experience of CTCA suggests that it performs well as a first-line investigation in patients with a wide range of predicted risk. The majority of patients presenting with stable chest pain ultimately have coronary artery disease excluded and CTCA is known to have excellent negative predictive value. ETT is known to result in a large number of equivocal outcomes leading to multiple second-line investigations. If CTCA could outperform ETT in patients with a wide range of predicted risk then it could significantly reduce the number of investigations required and the total cost burden on NHS chest pain services.

How did you implement the project

We compared two cohorts of patients pre-and post introduction of CT coronary angiography (CTCA) in our hospital presenting with stable chest pain to the Rapid Access Chest Pain Clinic. All patients were risk assessed and those with low-intermediate predicted risk were included in the audit. Those with very low or high risk were excluded. The first cohort was investigated with exercise tolerance testing (ETT) and the second with CTCA as first-line investigation. We compared the performance of each test in terms of ability to exclude coronary artery disease, requirement for second-line investigations and total cost per patient to reach diagnosis.

Key findings

CT coronary angiography (CTCA) outperformed exercise tolerance testing (ETT) for each of the comparative measures described above (see supporting document for full results). It excluded coronary artery disease more effectively (97.1% vs. 72.9%) and led to fewer second-line investigations (8.8% vs. 23.5%). As a result, the total cost per patient to reach diagnosis was significantly lower (-20.3%).

Key learning points

Exercise tolerance testing (ETT) has been widely shown to be a sub-optimal first-line investigation in patients presenting with stable chest pain. CT coronary angiography (CTCA) is a highly effective first-line investigation in those patients assessed to be at low-intermediate predicted risk of coronary artery disease. However, it is much less effective in patients with extensive coronary artery disease (due to coronary artery calcification degrading image quality) and alternative investigations such as functional testing or invasive coronary angiography are more appropriate. Clinical application of CTCA therefore relies on accurate risk assessment. If used appropriately it can lead to rapid rule-out of coronary artery disease in patients with non-cardiac chest pain, fewer second-line investigation and overall reduced cost to reach diagnosis.

Contact details

Name:
Toby Rogers
Job:
Cardiology Registrar
Organisation:
University Hospital Lewisham
Email:
toby.rogers@doctors.org.uk

Sector:
Secondary care
Is the example industry-sponsored in any way?
No