Examining the translational success of an initiative to accelerate the assessment of chest pain for patients in an Australian emergency department: a pre-post study.

BACKGROUND: The Improved assessment of chest pain trial (IMPACT) protocol is an accelerated strategy for the risk stratification and management of patients presenting to the emergency department (ED) with chest pain. This study sought to describe the adoption, sustainability and health services implications of implementing the IMPACT protocol. METHODS: This was a study of adult patients in a large Australian tertiary hospital who had serial troponin testing commenced within the ED. Data from two periods were utilized; the pre-implementation period (8th April 2012 to 5th April 2014) and the post-implementation period (6th April 2014 to 2nd April 2016). The primary outcome was the proportion of patients undergoing accelerated care. Secondary endpoints were ED assessment time, hospital length of stay, and costs. Data were compared in the pre- and post-implementation periods. RESULTS: The proportion of patients receiving accelerated care increased from 3% in the pre- to 34% in the post-intervention period. This increase occurred rapidly after implementation of IMPACT and was sustained over a 2-year period. For patients with troponin concentrations <99th percentile, the mean ED assessment time reduced from 12.3 h in the pre- to 10.1 h in the post-implementation period. Mean hospital length of stay was similar in the pre- and post-implementation periods (82.4 and 80.9 h). The average cost of chest pain assessment reduced from $3520 pre implementation to $3204 post implementation; a $316 reduction per patient. CONCLUSIONS: The IMPACT protocol was rapidly adopted and utilised after implementation into standard care. The initial increase in the proportion of patients undergoing accelerated assessment, followed by a plateau towards the end of the study period indicate adoption and sustainability of the IMPACT protocol over a two-year period. Modest reductions in length of stay and cost were seen after implementation. Given the large number of patients investigated for chest pain, such reductions may have substantial impact on the overall healthcare system.

Utility of Routine Exercise Stress Testing among Intermediate Risk Chest Pain Patients Attending an Emergency Department.

BACKGROUND: To assess the utility of routine exercise stress testing (EST) in patients at intermediate risk of acute coronary syndrome (ACS) according to the Heart Foundation of Australia/Cardiac Society of Australia and New Zealand (HFA/CSANZ) guidelines. METHOD: Prospective observational study of patients presenting to the Emergency Department (ED) with chest pain suggestive of ACS between November 2008 and July 2014. Participants included 1205 patients who presented to the ED with chest pain suggestive of ACS and who met the HFA/CSANZ intermediate risk criteria. The outcome was diagnosis of ACS occurring on presentation or within 30 days of presentation to the ED. ACS included acute myocardial infarction and unstable angina pectoris. RESULTS: Twenty (1.66%) of the intermediate risk patients were diagnosed with ACS. Of the 777 patients who underwent EST, eight had ACS. EST identified all ACS cases except for one patient with a negative test, who was ultimately diagnosed with ACS following angiography. 164 patients deemed inappropriate to undergo EST underwent an alternative form of objective testing, of which 12 were positive for ACS. 264 patients underwent no objective testing. CONCLUSION: EST stratifies intermediate risk patients to a near zero short-term risk of ACS. However, the overall yield of EST within this group of patients is extremely low. Intermediate risk patients with normal zero and six hour biomarkers have a very low probability of ACS, and over half of these patients ultimately diagnosed with ACS in this group were deemed unsuitable for EST anyway. Future research should focus on the identification of patients who do not require EST and the inclusion of routine EST within the HFA/CSANZ guidelines should be reconsidered.

Sex-specific versus overall cut points for a high sensitivity troponin I assay in predicting 1-year outcomes in emergency patients presenting with chest pain.

OBJECTIVE: To evaluate the incidence of major adverse cardiac events (MACE) at 1 year in emergency department (ED) patients with possible acute coronary syndromes, stratified by high sensitivity troponin (hs-cTnI) concentrations using sex-specific cut points compared with overall cut points. METHODS: In a multicentre observational study of 2841 patients, presentation hs-cTnI concentrations were categorised using sex-specific (women 16 ng/L; men 34 ng/L) and overall (26 ng/L) cut points. The primary outcome was MACE occurring within 1 year of presentation. Patients with hs-cTnI values concentrations within these categories were reported by sex and 1-year MACE. Net reclassification improvement (NRI) was computed to measure the change in prediction after altering the hs-cTnI cut points, and was calculated separately for events and non-events. RESULTS: Application of sex-specific 99th percentile cut points rather than the overall cut point of 26 ng/L, reclassified 25 females from having a non-elevated troponin to having an elevated troponin, and 29 males from having an elevated troponin value to having a non-elevated troponin value on presentation. Of these, 7 (28.0%) females and 12 (41.4%) males had a 1-year MACE. There was no reclassification improvement for those with or without 1-year MACE (NRIevents=-1.5%, 95% CI -4.0% to 1.1%; NRInon-events -0.04%, 95% CI -0.5% to 0.4%). CONCLUSIONS: Sex-specific cut points improve the identification of women but not men at risk for 1-year MACE. The net-effect across the whole ED population with possible cardiac chest pain is minimal. Lowering the clinical cut point for both sexes may be appropriate for prognostic purposes. TRIAL REGISTRATION NUMBER: ISRCTN No. 21109279, ACTRN12609000283279.