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Abstract
Objectives Recent guidance recommended use of high-sensitivity troponin for rapid rule out of myocardial infarction (MI) in the English health service. We aimed to determine the extent of implementation of this guidance across English hospitals.
Methods This study conducted a cross-sectional questionnaire survey of 131 English acute hospitals with over 10 000 admissions per year.
Results We received 125/131 responses (95%), with 110/125 (88%) reporting use of a high-sensitivity troponin assay and responses showing progressive implementation over the last 10 years. High-sensitivity troponin was reported to be used for rapid rule out of MI in 92/110 Trusts (84%). Review of guidelines received from 95/110 Trusts identified that 71/95 (75%) provided guidance for rapid MI rule out with high-sensitivity troponin: 57 recommended testing at 0 and 3 hours, 4 recommended testing at 0 and 2 hours, and 9 recommended testing at 0 and 1 hour, and timing was unclear at one Trust.
Conclusions English acute hospital Trusts report widespread implementation of high-sensitivity troponin for rapid rule out of MI, with most recommending testing at 0 and 3 hours.
- troponin
- myocardial infarction
- guidelines
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Key messages
What is already known on this subject
High-sensitivity troponin can be used to rule out myocardial infarction (MI) within a few hours of arrival at hospital.
Recent guidance recommends using high-sensitivity troponin to rule out MI in the English health service.
What this paperstudy adds
English acute hospital Trusts report widespread implementation of high-sensitivity troponin for rapid rule out of myocardial infarction.
Most hospitals providing guidelines recommended testing at 0 and 3 hours.
Background
Emergency admissions (requiring provision of a hospital bed) to English hospitals with unspecified chest pain increased from 118 828 in 1998–1999 to a peak of 248 197 in 2010–2011 before falling to 232 598 in 2017–2018.1 The most likely reason for admission for these cases is to rule out myocardial infarction (MI). The recent development of high-sensitivity troponin assays offers the potential to allow rapid rule out of MI and thus reduces admissions with chest pain. In 2014, new guidance from the National Institute for Health and Care Excellence (NICE) recommended using high-sensitivity troponin assays to rule out MI within 3 hours of hospital attendance,2 which was incorporated into updated NICE chest pain guidance in 2016.3 We aimed to determine whether NICE guidance regarding the use of high-sensitivity troponin to rule out MI has been implemented across English hospitals.
Methods
We conducted a survey of all acute NHS hospital Trusts in England with more than 10 000 emergency admissions in the year 2017/2018, excluding children’s and maternity hospitals.1 We sent a short questionnaire through email and online forms via a freedom of information (FOI) access request to 131 eligible Trusts in April 2019. The questionnaire was designed to be completed with minimal time and effort, using readily available information, and is shown in online supplementary appendix 1. The questionnaire was sent to the FOI administrator but it was not possible to determine who subsequently provided the information. Trust guidelines or protocols were reviewed to determine the timing of troponin sampling and whether troponin measurements were used to rule out MI within 4 hours of hospital admission. This was determined by the last sample being no later than 3 hours from hospital arrival or initial sampling to allow for time taken to take blood and retrieve results.
Supplemental material
Results
We received 125/131 (95%) responses between April and August 2019, with 110 (88%) reporting use of a high-sensitivity troponin assay. Figure 1 shows the number of Trusts introducing the assay per year (excluding three that did not respond to this question), indicating progressive implementation over the last 10 years. Around half implemented high-sensitivity assays before the 2014 NICE guidance and half after.
Year of implementation of high-sensitivity troponin at English acute hospital Trusts.
The assay used was manufactured by Roche in 63/110 (57%) Trusts, Abbott in 16 (14%), Beckman Coulter in 12 (11%) and Siemens in 12 (11%), with one Trust using both Roche and Abbott assays and six (5%) not responding to this question. It is worth noting that the NICE guidance only recommended the Elecsys Troponin T high-sensitive assay (Roche) and the ARCHITECT STAT high-sensitive Troponin-I (Abbott) for clinical use, while the AccuTnI+3 assay (Beckman Coulter) was only recommended for clinical research. The threshold for positivity was reported by 97/110 Trusts, with 79 using the 99th percentile (25 sex-specific, 54 overall), 12 using a higher threshold and 6 using a lower threshold, of which 3 appeared to be the limit of detection.
High-sensitivity troponin was reported to be used for rapid rule out of MI in 92/110 Trusts (84%), with one additional Trust reporting use for rule out in only one of its two sites. We received copies of guidelines from 95/110 Trusts. Review of the guidelines identified 71/95 (75%) using high-sensitivity troponin for rapid rule out of MI: 57 recommended testing at 0 and 3 hours, 4 recommended 0 and 2 hours, and 9 recommended 0 and 1 hour, and timing was unclear at one Trust.
Discussion
English acute hospital Trusts report widespread use of high-sensitivity troponin for rapid rule out of MI, suggesting that recent NICE guidance has been widely implemented. Most hospitals use high-sensitivity troponin and most of these use it for rapid rule out of MI. The most commonly used assay is the Roche high-sensitivity troponin T. Timing of sampling varies, with most Trusts recommending sampling at 0 and 3 hours, but some recommending shorter time intervals. The findings suggest that availability of high-sensitivity troponin has increased since a survey of 94 hospital laboratories in 2015 reported that 60% had implemented a high-sensitivity troponin assay.4 A recent international survey reported that 72% of 80 UK sites use high-sensitivity troponin, with serial sampling at 3–6 hours in 78%.5 Our findings report a slightly higher use of high-sensitivity troponin (88%) across a larger and potentially more representative sample, with additional detail regarding timings and assays used.
The survey has strengths and limitations. The response rate was high, facilitated by the FOI request and simple design, thus ensuring a comprehensive sample of English Trusts. A disadvantage of this approach is that we were unable to specify or determine who completed the survey. It is limited to England, so it is unclear whether similar uptake of high-sensitivity troponin testing has occurred in the devolved nations of the UK. It describes reported practice rather than actual practice, so it is unclear whether the guidance presented is actually followed.
The last point is probably the most salient. Our survey suggests progressive implementation of NICE guidance across the English NHS that may be reflected in admission rates for chest pain, which have plateaued and started to fall after showing a progressive rise prior to implementation of high-sensitivity troponin.1 However, NICE guidance anticipated that implementation would lead to markedly reduced admissions, which is not yet obvious from routinely available data. It has been suggested elsewhere6 that high-sensitivity troponins could lead to overdiagnosis and overinvestigation. Further research could explore whether implementation of high-sensitivity troponin testing at different times across different Trusts over the last decade is associated with an effect on admissions with chest pain.
As noted in the Results section, NICE did not recommend the Beckman Coulter assay as a high-sensitivity assay and Siemens have only recently released a high-sensitivity assay. The 22% of Trusts reporting use of these assays may therefore not have genuinely been using a high-sensitivity assay.
In conclusion, English acute hospital Trusts report widespread implementation of high-sensitivity troponin for rapid rule out of MI, with most recommending testing at 0 and 3 hours.
Acknowledgments
We thank the Trusts for providing the data.
Supplementary materials
Supplementary Data
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Footnotes
Contributors SG conceived the study. SG and RW designed the study. ST collected and analysed the data. ST wrote the first draft. All authors contributed to redrafting and approved the final draft.
Funding The University of Sheffield funded the study.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request.