Impact case study database

Impact on clinical guidelines

The NICE Clinical Guideline for the assessment and diagnosis of chest pain of recent onset (CG95) was updated in 2016, and now recommends CTCA as the first-line testing strategy in patients with stable chest pain [5.1a]. Further investigations are only recommended when CTCA results are inconclusive. The draft for consultation refers to the SCOT-HEART trial 22 times, and it was 1 of only 3 randomised controlled trials listed in evidence for review question 1 (“In people with stable chest pain of suspected cardiac origin, what is the accuracy, clinical utility and cost-effectiveness of non-invasive diagnostic tests, invasive diagnostic tests and calcium scoring?”). The SCOT-HEART trial is described in detail in both the evidence summary [p. 26; 5.1b] and evidence tables in Appendix G [p. 359–362; 5.1b]. The NICE guideline CG95 was reviewed in September 2019 and no new evidence was identified which would have changed the recommendations [5.1c].

The European Society of Cardiologists (ESC) updated its guidelines in 2019, and now also recommends CTCA as the initial test to diagnose stable chest pain [5.2]. This updated version elevates CTCA from a Class IIb recommendation (“may be considered”) to a Class I recommendation (“is recommended or is indicated”), and specifically highlights SCOT-HEART as evidence in favour of CTCA [5.2] as well as citing 4 UoE papers.

Impact on clinical practice

United Kingdom

Since the update to NICE CG95 in 2016, the use of CTCA has more than doubled in the UK, while use of other cardiac imaging methods has remained stable. These trends can be seen in electronic imaging records held by NHS Digital ( Figure 1 below): from 2016 onwards: there was a sharp upturn in the average annual growth of CTCA scans performed in England, from 21.9 ± 52.8 tests per 100,000 people per year before the CG95 update, to 52.8 ± 79.1 tests per 100,000 people per year after the update, p<0.001) [5.3].

Figure 1. England-wide numbers of examinations performed for the investigation of CAD by method, 2012–2018 [5.3]. (Acronyms are defined in section 2)

A global survey of uptake of the ESC guidelines, conducted by the European Association of Cardiovascular Imaging Scientific Initiatives Committee in 2020, revealed that in 110 imaging centres in 37 countries across the world, CTCA was the most commonly used non-invasive diagnostic test, with 31% of respondents using it as the principal test for diagnosing CAD (compared with 15% stress echocardiography, 12% exercise electrocardiogram, 5% SPECT or PET and 4% MRI). Only 1% of centres proceeded directly to ICA [5.4].

Impact on health & welfare

The improved diagnostic accuracy offered by CTCA saves lives of patients with CAD, as evidenced by SCOT-HEART, which showed that patients who had undergone CTCA were 41% less likely to die from CAD or experience non-fatal MI than those who had not.

The real-life impact of this can be projected as follows: based on the data from the national imaging records [5.3], 51–52 CTCA scans are required to prevent 1 MI in 5 years; thus, the 53 CTCAs per 100,000 population performed per year since 2016 prevented 1 MI per 100,000 population per year. Scaling this up to the UK population of 66,000,000 people, this rate of use of CTCA is preventing approximately 660 MIs per year.

Economic impact

A health economic analysis was undertaken as part of the 2016 update to NICE CG95 to determine the cost-effectiveness of the various testing strategies for diagnosing stable chest pain [5.1b]. This compared the average proportion of correct diagnoses (effectiveness) and the costs of each testing strategy (from NHS Reference Costs: CTCA GBP122.11, exercise test GBP271.31, SPECT GBP367.29, MRI GBP515, ICA GBP1,684.71). This analysis found that a first-line testing strategy using CTCA has the lowest cost per correct diagnosis of CAD [5.5].

Furthermore, a NICE report on the resource impact of implementing CG95 [5.6] estimated that the recommended change in diagnostic tests performed would lead to annual savings increasing year-on year from GBP1,132,000 in 2016–17 to GBP16,974,000 by 2020–21 through better targeted use of NHS resources and reducing future adverse cardiac events.

Use of CTCA also results in cost-savings outside the UK. An independent randomised controlled trial run in the USA and South Korea found that when patients were triaged by CTCA rather than being directly referred to ICA, total diagnostic costs per patient were 57% lower (an average of USD2,755 [GBP2,105; 01-21] in the direct referral group versus USD1,183 [GBP902; 01-21] in the CTCA-triaged group) with no difference in clinical outcomes [5.7].