Introduction NICE guidelines recommend functional testing for chest pain of recent onset where there is an intermediate pre-test probability (30–59%) of ischaemic heart disease using the Diamond Forrester (DF) score . When the pre-test probability is low (10–29%), cardiac CT is recommended, and for patients with a high pre-test probability, invasive coronary angiography is recommended. In practice however, pathways can be influenced by local availability of imaging modalities. This audit aimed to assess appropriateness of referrals and outcome of patients referred for DSE in a district general hospital.
Methodology A retrospective audit of patients undergoing DSE from 1st Nov 2015–1st May 2016 was undertaken. Baseline demographics, risk factors, DF score and DSE outcome (positive or negative for ischaemia) were recorded. For patients with a positive DSE, findings at angiography were assessed. For patients with a negative study, the electronic care record was reviewed to assess incidence of adverse outcomes including acute coronary syndrome (ACS) and mortality. Statistical analysis was performed using Chi square test for parametric categorical variables and Mann Whitney U test for parametric continuous variables, p<0.05 taken as significant.
Results In total, 62 patients underwent DSE; 33 (53%) were male. Mean age was 67.5 yrs (SD 10.9 yrs). Mean DF score was 48% (SD 21%). In total 31 (50%) had a DF pre-test probability of 30–59% and were therefore appropriately referred according to NICE guidelines. Ten patients (16.2%) had a positive DSE of which 9 (90%) were male (see table 1). In the DSE positive group the mean DF score was 72%, range 12–89% (SD 23%) compared with a mean DF score of 46%, range 14–92% (SD 18%) in the DSE negative group, p<0.05. With the exception of one patient in the DSE positive group (DF 12%), all patients had a DF score of 60–89%, and according to NICE guidance would have proceeded directly to invasive angiography. Of the 10 positive DSEs, 9 had obstructive coronary disease at angiography and 5 proceeded to intervention.
In the DSE negative group, 30 (58%) had a DF score 30–59%, 7 (13.5%) patients had a DF score 60–89%, and 15 (28.8%) had a DF score 10–29%.
Of the 52 (83.4%) patients with negative DSE, there were no admissions for ACS during a follow up period of 6–18 months and no mortality.
Conclusion Patients referred for DSE had a range of DF scores with only 50% patients being appropriately referred according to NICE guidelines. Despite this, DSE correctly identified patients with obstructive coronary disease which required further therapy with a high degree of specificity. Patients with negative studies appear to have a low risk of cardiac events in the short to medium term despite an average DF score of 46%.
Local referral patterns do not adhere to NICE guidance and this may be influenced by access to investigations. DSE appears to identify high and low risk groups even across a range of DF scores.
Reference 1. Chest pain of recent onset: Assessment and Diagnosis. NICE Guidelines [CG95] Published Date: March 2010 (updated Nov 2016)
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