Balancing the Risks of Recurrent Ischaemic and Bleeding Events in a Stable Post ACS Population.

OBJECTIVE: To better guide decisions regarding antithrombotic treatment in individual patients surviving 6 months following an acute coronary syndrome (ACS) by balancing between subsequent recurrent ischaemic and bleeding risk. METHODS: Patients surviving 6 months following an ACS were followed in an Australian registry. Ischaemic (composite of cardiovascular death, myocardial infarction or stroke) and bleeding (≥BARC 2) events were collected. A dual binary outcome modelling strategy was used arriving at a common set of variables from which bleeding and ischaemic risk could be independently determined in individual patients. Patients in whom bleeding rates exceeded composite ischaemic event rates during the follow-up period were identified. RESULTS: The cohort comprised 5,905 patients in whom 215 experienced an ischaemic event and 49 a bleeding event. The single set of variables included in both ischaemic and bleeding models (C-statistics 0.71 and 0.72 respectively) included modified TIGRIS1 ischaemic score, mode of revascularisation, history of heart failure, anaemia, multivessel disease, readmission within 6 months of index ACS and age >75. In the majority, ischaemic events were more frequent than bleeding events. In higher risk patients post coronary artery bypass grafting (CABG), bleeding events were more frequent than recurrent ischaemic events. CONCLUSION: The risk of recurrent ischaemic events exceeds bleeding in most patients followed 6 to 24 months following an ACS. Post CABG patients with comorbidities have a higher risk of bleeding over this period during which time attention should be directed towards modifiable bleeding risk factors including requirement for dual antiplatelet therapy.

Composite Echocardiographic Score to Predict Long-Term Survival Following Myocardial Infarction.

BACKGROUND: Whilst the left ventricular ejection fraction (LVEF) remains the primary echocardiographic measure widely utilised for risk stratification following myocardial infarction (MI), it has a number of well recognised limitations. The aim of this study was to compare the prognostic utility of a composite echocardiographic score (EchoScore) composed of prognostically validated measures of left-ventricular (LV) size, geometry and function, to the utility of LVEF alone, for predicting survival following MI. METHODS: Retrospective data on 394 consecutive patients with a first-ever MI were included. Comprehensive echocardiography was performed within 24 hours of admission for all patients. EchoScore consisted of LVEF<50%, left atrial volume index>34 mL/m2, average E/e >14, E/A ratio>2, abnormal LV mass index, and abnormal LV end-systolic volume index. A single point was allocated for each measure to derive a score out of 6. The primary outcome measure was all-cause mortality. RESULTS: At a median follow-up of 24 months there were 33 deaths. On Kaplan-Meier analysis, a high EchoScore (>3) displayed significant association with all-cause mortality (log-rank χ2=74.48 p<0.001), and was a better predictor than LVEF<35% (log-rank χ2=17.01 p<0.001). On Cox proportional-hazards multivariate analysis incorporating significant clinical and echocardiographic predictors, a high EchoScore was the strongest independent predictor of all-cause mortality (HR 6.44 95%CI 2.94-14.01 p<0.001), and the addition of EchoScore resulted in greater increment in model power compared to addition of LVEF (model χ2 56.29 vs 44.71 p<0.001, Harrell's C values 0.83 vs 0.79). CONCLUSIONS: A composite echocardiographic score composed of prognostically validated measures of LV size, geometry, and function is superior to LVEF alone for predicting survival following MI.

Oral Anticoagulant Use in Patients With Atrial Fibrillation and Chronic Kidney Disease: A Review of the Evidence With Recommendations for Australian Clinical Practice.

Chronic kidney disease is common in patients with atrial fibrillation (AF) and is associated with heightened risks of stroke/systemic embolisation and bleeding. In this review we outline the evidence for AF stroke prevention in kidney disease, identify current knowledge gaps, and give recommendations for anticoagulation at various stages of chronic kidney disease. Overall, anticoagulation is underused. Warfarin use becomes increasingly difficult with advancing kidney disease, with difficulty maintaining international normalised ratio (INR) in therapeutic range, increased risk of intracranial and fatal bleeding compared to non-vitamin K oral anticoagulants (NOACs), and high rates of discontinuation. Similarly, the direct thrombin inhibitor dabigatran is not recommended as it is predominantly renally excreted with consequent increased plasma levels and bleeding risk with advanced kidney disease. The Factor Xa inhibitors apixaban and rivaroxaban have less renal excretion (25-35%), modest increases in plasma levels with advancing kidney disease, and are the preferred first line choice for anticoagulation in moderate kidney disease based on strong evidence from randomised clinical trials (RCTs). In severe kidney disease there is a paucity of RCT data, but extrapolation of the pharmacokinetic and RCT data for moderate kidney disease, and observational studies, support the considered use of dose-adjusted Factor Xa inhibitors unless the bleeding risk is prohibitive. In Australia, apixaban is approved for creatinine clearance down to 25 mL/min, and rivaroxaban down to 15 mL/min. For end-stage kidney disease warfarin is the only agent approved, but we recommend against anticoagulation (except in selected cases) due to high bleeding risk, multiple co-morbidities, and questionable benefit.

Determinants of Diastolic Dysfunction Following Myocardial Infarction: Evidence for Causation Beyond Infarct Size.

BACKGROUND: The determinants of severe diastolic dysfunction (DD) following myocardial infarction (MI) are not well defined. This study sought to define the determinants of severe DD (restrictive mitral inflow pattern on Doppler echocardiography [RFP]) in patients with a first-ever MI, with particular emphasis on the impact of infarct size. METHODS: Retrospective single-centre study including consecutive patients admitted to a tertiary referral centre with a first-ever non-ST-elevation-MI (NSTEMI) or ST-elevation-MI (STEMI) (n=477). Peak troponin-I (Peak-TnI) was used as the principal measure of infarct size, whilst left ventricular ejection fraction (LVEF) and wall motion score index (WMSI) were regarded as surrogate measures. Echocardiography was performed within 24 hours of admission for all patients. RFP was defined as E/A ratio >2.0 or E/A ratio >1.5 and E-wave deceleration time <140 ms. RESULTS: A total of 69 patients (14.5%) had RFP. Peak-TnI levels were higher in the RFP group (32.6±32.7 versus 16.9±25.2 µg/L, p<0.001). In sequential multivariable models incorporating significant clinical, angiographic and left ventricular (LV) size-related variables, Peak-TnI (OR 1.98, p=0.001), WMSI (OR 2.34, p=0.048) and LVEF (OR 0.97, p=0.044) were independent predictors of RFP. Presence of diabetes was also an independent predictor in all the models constructed. When patients were stratified according to an LVEF of 50%, 39% of RFP patients had a preserved LVEF (RFP/preserved EF group), and these patients had lower Peak-TnI levels compared to the RFP/reduced EF group (14.4±18.7 vs 44.5±35.5 µg/L). CONCLUSIONS: Whilst infarct size is a major determinant of severe diastolic dysfunction after MI, a significant subset of patients develop severe diastolic dysfunction despite a small infarct size and preserved LVEF, highlighting that other factors such as pre-existing diastolic dysfunction due to risk factors such as diabetes have an important role in causation.

Pre-hospital administration of ticagrelor in diabetic patients with ST-elevation myocardial infarction undergoing primary angioplasty: A sub-analysis of the ATLANTIC trial.

OBJECTIVE: We investigated, in the contemporary era of ST-elevation myocardial infarction (STEMI) treatment, the influence of diabetes mellitus (DM) on cardiovascular outcomes, and whether pre-hospital administration of ticagrelor may affect these outcomes in a subgroup of STEMI patients with DM. BACKGROUND: DM patients have high platelet reactivity and a prothrombotic condition which highlight the importance of an effective antithrombotic regimen in this high-risk population. METHODS: In toal 1,630 STEMI patients enrolled in the ATLANTIC trial who underwent primary percutaneous coronary intervention (PCI) were included. Multivariate analysis was used to explore the association of DM with outcomes and potential treatment-by-diabetes interaction was tested. RESULTS: A total of 214/1,630 (13.1%) patients had DM. DM was an independent predictor of poor myocardial reperfusion as reflected by less frequent ST-segment elevation resolution (≥70%) after PCI (OR 0.59, 95% CI 0.43-0.82, P < 0.01) and was an independent predictor of the composite 30-day outcomes of death/new myocardial infarction (MI)/urgent revascularization/definite stent thrombosis (ST) (OR 2.80, 95% CI 1.62-4.85, P < 0.01), new MI or definite acute ST (OR 2.46, 95% CI 1.08-5.61, P = 0.03), and definite ST (OR 10.00, 95% CI 3.54-28.22, P < 0.01). No significant interaction between pre-hospital ticagrelor vs in-hospital ticagrelor administration and DM was present for the clinical, electrocardiographic and angiographic outcomes as well as for thrombolysis in myocardial infarction major bleeding. CONCLUSIONS: DM remains independently associated with poor myocardial reperfusion and worse 30-day clinical outcomes. No significant interaction was found between pre-hospital vs in-hospital ticagrelor administration and DM status. Further approaches for the treatment of DM patients are needed. CLINICAL TRIAL REGISTRATION: clinicaltrials.gov identifier: NCT01347580.

Duration of ischemia and treatment effects of pre- versus in-hospital ticagrelor in patients with ST-segment elevation myocardial infarction: Insights from the ATLANTIC study.

BACKGROUND: Among patients with STEMI in the ATLANTIC study, pre-hospital administration of ticagrelor improved post-PCI ST-segment resolution and 30-day stent thrombosis. We investigated whether this clinical benefit with pre-hospital ticagrelor differs by ischemic duration. METHODS: In a post hoc analysis we compared absence of ST-segment resolution post-PCI and stent thrombosis at 30 days between randomized treatment groups (pre- versus in-hospital ticagrelor) stratified by symptom onset to first medical contact (FMC) duration [≤1 hour (n = 773), >1 to ≤3 hours (n = 772), and >3 hours (n = 311)], examining the interaction between randomized treatment strategy and duration of symptom onset to FMC for each outcome. RESULTS: Patients presenting later after symptom onset were older, more likely to be female, and have higher baseline risk. Patients with symptom onset to FMC >3 hours had the greatest improvement in post-PCI ST-segment elevation resolution with pre- versus in-hospital ticagrelor (absolute risk difference: ≤1 hour, 2.9% vs. >1 to ≤3 hours, 3.6% vs. >3 hours, 12.2%; adjusted p for interaction = 0.13), while patients with shorter duration of ischemia had greater improvement in stent thrombosis at 30 days with pre- versus in-hospital ticagrelor (absolute risk difference: ≤1 hour, 1.3% vs. >1 hour to ≤3 hours, 0.7% vs. >3 hours, 0.4%; adjusted p for interaction = 0.55). Symptom onset to active ticagrelor administration was independently associated with stent thrombosis at 30 days (adjusted OR 1.89 per 100 minute delay, 95%CI 1.20-2.97, P < .01), but not post-PCI ST-segment resolution (P = .41). CONCLUSIONS: The effect of pre-hospital ticagrelor to reduce stent thrombosis was most evident when given early within 3 hours after symptom onset, with delay in ticagrelor administration after symptom onset associated with higher rate of stent thrombosis. These findings re-emphasize the need for early ticagrelor administration in primary PCI treated STEMI patients.

Prehospital ticagrelor in ST-segment elevation myocardial infarction.

BACKGROUND: The direct-acting platelet P2Y12 receptor antagonist ticagrelor can reduce the incidence of major adverse cardiovascular events when administered at hospital admission to patients with ST-segment elevation myocardial infarction (STEMI). Whether prehospital administration of ticagrelor can improve coronary reperfusion and the clinical outcome is unknown. METHODS: We conducted an international, multicenter, randomized, double-blind study involving 1862 patients with ongoing STEMI of less than 6 hours' duration, comparing prehospital (in the ambulance) versus in-hospital (in the catheterization laboratory) treatment with ticagrelor. The coprimary end points were the proportion of patients who did not have a 70% or greater resolution of ST-segment elevation before percutaneous coronary intervention (PCI) and the proportion of patients who did not have Thrombolysis in Myocardial Infarction flow grade 3 in the infarct-related artery at initial angiography. Secondary end points included the rates of major adverse cardiovascular events and definite stent thrombosis at 30 days. RESULTS: The median time from randomization to angiography was 48 minutes, and the median time difference between the two treatment strategies was 31 minutes. The two coprimary end points did not differ significantly between the prehospital and in-hospital groups. The absence of ST-segment elevation resolution of 70% or greater after PCI (a secondary end point) was reported for 42.5% and 47.5% of the patients, respectively. The rates of major adverse cardiovascular events did not differ significantly between the two study groups. The rates of definite stent thrombosis were lower in the prehospital group than in the in-hospital group (0% vs. 0.8% in the first 24 hours; 0.2% vs. 1.2% at 30 days). Rates of major bleeding events were low and virtually identical in the two groups, regardless of the bleeding definition used. CONCLUSIONS: Prehospital administration of ticagrelor in patients with acute STEMI appeared to be safe but did not improve pre-PCI coronary reperfusion. (Funded by AstraZeneca; ATLANTIC ClinicalTrials.gov number, NCT01347580.).

Validating the Manchester Acute Coronary Syndromes (MACS) and Troponin-only Manchester Acute Coronary Syndromes (T-MACS) rules for the prediction of acute myocardial infarction in patients presenting to the emergency department with chest pain.

BACKGROUND: The Manchester Acute Coronary Syndromes (MACS) rule and the Troponin-only MACS (T-MACS) rule risk stratify patients with suspected acute coronary syndrome (ACS). This observational study sought to validate and compare the MACS and T-MACS rules for assessment of acute myocardial infarction (AMI). METHODS: Prospectively collected data from twoEDs in Australia and New Zealand were analysed. Patients were assigned a probability of ACS based on the MACS and T-MACS rules, incorporating high-sensitivity troponin T, heart-type fatty acid-binding protein, ECG results and clinical symptoms. Patients were then deemed very low risk, low risk, intermediate or high risk if their MACS probability was less than 2%, between 2% and 5%, between 5% and 95% and greater than 95%, respectively. The primary endpoint was 30-day diagnosis of AMI. The secondary endpoint was 30-day major adverse cardiac event (MACE) including AMI, revascularisation or coronary stenosis (>70%). Sensitivity, specificity and predictive values were calculated to assess the accuracy of the MACS and T-MACS rules. RESULTS: Of the 1244 patients, 114 (9.2%) were diagnosed with AMI and 163 (13.1%) with MACE. The MACS and T-MACS rules categorised 133 (10.7%) and 246 (19.8%) patients, respectively, as very low risk and potentially suitable for early discharge from the ED. There was one false negative case for both rules making sensitivity 99.1% (95.2%-100%). CONCLUSIONS: MACS and T-MACS accurately risk stratify very low risk patients. The T-MACS rule would allow for more patients to be discharged early. The potential for missed MACE events means that further outpatient testing for coronary artery disease may be required for patients identified as very low risk.

Differences in Presentation, Management and Outcomes in Women and Men Presenting to an Emergency Department With Possible Cardiac Chest Pain.

BACKGROUND: Research suggests that female patients with acute coronary syndrome (ACS) experience delays in emergency department (ED) management and are less likely to receive guideline-based treatments and referrals for follow-up testing. Women are often found to have poorer clinical outcomes in comparison to men. This study aimed to assess current sex differences in the presentation, management and outcomes of patients with undifferentiated chest pain presenting to a tertiary ED. METHODS: Data were analysed from two prospective studies conducted at a single Australian site between 2007 and 2014. Eligible patients were those of 18 years of age or older presenting with at least 5 minutes of chest pain or other symptoms for which the treating physician planned to investigate for possible ACS. Presenting symptoms, ED time measures, follow-up testing and outcomes, including 30-day ACS and mortality, were measured and compared between male and female patients. RESULTS: Of 2349 (60% men) patients presenting with chest pain, 153 men and 51 women were diagnosed with ACS within 30days . Presenting symptoms were similar in men and women with confirmed ACS. Time from symptom onset to ED presentation, time spent in the ED and total time in hospital were similar between the sexes. Male and female patients had similar rates of follow-up provocative testing. After adjustment for clinical factors, the odds of undergoing angiography were 1.8 (95% CI: 1.36-2.40) times higher for men than women. Of those undergoing coronary angiography within 30 days, a smaller proportion of women, compared to men, received revascularisation. Within 30 days, three (0.2%) male and one (0.1%) female patient died. CONCLUSION: Minimal sex differences were observed in the contemporary emergency management of patients presenting with suspected ACS. Thirty-day outcomes were similarly low in men and women despite lower rates of coronary angiography and revascularisation in women. Further research is required to replicate these results in different hospital systems and cultural settings.

Suspected ACS Patients Presenting With Myocardial Damage or a Type 2 Myocardial Infarction Have a Similar Late Mortality to Patients With a Type 1 Myocardial Infarction: A Report From the Australian and New Zealand 2012 SNAPSHOT ACS Study.

BACKGROUND: Cardiac troponin (T and I) are considered the standard markers for detection of myocardial damage and the diagnosis of acute coronary syndrome (ACS) among patients who present to an emergency department with chest pain. However, these markers can be released in other situations and may be associated with short- and long-term clinical outcomes. In this study, we examine late mortality rates among patients presenting with a suspected ACS due to an unstable coronary plaque and those patients having a non-ACS. METHODS: 4388 patients were hospitalised with suspected ACS, between 14 and 27 May 2012 in the Australia and New Zealand SNAPSHOT ACS study. Those patients were categorised in five diagnostic groups: 1) ST elevation MI (n=419); 2) non-ST elevation MI (n=1012); 3) unstable angina (n=925); 4) non-ACS diagnoses (n=837); and 5) chest pain considered unlikely ischaemic (not otherwise specified, n=1195). RESULT: The respective mortality rates at 18 months in these groups were 16.2%, 16.3%, 6.8%, 12.8%, and 4.8%; Pearson χ2=110 p<0.001. Among non-ACS diagnoses patients (group 4) those with the highest mortality rates (cardiac (14.4%), respiratory (18.2%), sepsis (15.4%) and neoplastic (67%) diagnoses) had the highest rates of elevated troponin levels (48%, 31%, 38% and 67% respectively). By contrast, those with the lowest mortality rates (musculoskeletal (2.9%), gastrointestinal disorders (3.9%) and non-specific chest pain (7.4%)) had the lowest rate of elevated troponin levels (9%, 18% and 15.8% respectively). However, after adjusting for baseline clinical and demographic characteristics, the mortality rate at 18 months for patients with elevated troponin was similar for ACS or non-ACS diagnoses (Hazard Ratio, 95% C.I.0.98-1.07, p=0.333). CONCLUSIONS: Among patients in the 2012 SNAPSHOT ACS study, non-ACS diagnoses characterised by high rates of elevated troponin levels had high mortality rates similar to those diagnosed with ACS. Therapies known to be effective in ACS patients, including early invasive management, should be examined in these non-ACS patients with troponin elevations within adequately powered randomised trials.

Two-Hour Algorithm for Triage toward Rule-Out and Rule-In of Acute Myocardial Infarction by Use of High-Sensitivity Cardiac Troponin I.

BACKGROUND: The early triage of patients toward rule-out and rule-in of acute myocardial infarction (AMI) is challenging. Therefore, we aimed to develop a 2-h algorithm that uses high-sensitivity cardiac troponin I (hs-cTnI). METHODS: We prospectively enrolled 1435 (derivation cohort) and 1194 (external validation cohort) patients presenting with suspected AMI to the emergency department. The final diagnosis was adjudicated by 2 independent cardiologists. hs-cTnI was measured at presentation and after 2 h in a blinded fashion. We derived and validated a diagnostic algorithm incorporating hs-cTnI values at presentation and absolute changes within the first 2 h. RESULTS: AMI was the final diagnosis in 17% of patients in the derivation and 13% in the validation cohort. The 2-h algorithm developed in the derivation cohort classified 56% of patients as rule-out, 17% as rule-in, and 27% as observation. Resulting diagnostic sensitivity and negative predictive value (NPV) were 99.2% and 99.8% for rule-out; specificity and positive predictive value (PPV) were 95.2% and 75.8% for rule-in. Applying the 2-h algorithm in the external validation cohort, 60% of patients were classified as rule-out, 13% as rule-in, and 27% as observation. Diagnostic sensitivity and NPV were 98.7% and 99.7% for rule-out; specificity and PPV were 97.4% and 82.2% for rule-in. Thirty-day survival was 100% for rule-out patients in both cohorts. CONCLUSIONS: A simple algorithm incorporating hs-cTnI baseline values and absolute 2-h changes allowed a triage toward safe rule-out or accurate rule-in of AMI in the majority of patients.

A Clinical Decision Rule to Identify Emergency Department Patients at Low Risk for Acute Coronary Syndrome Who Do Not Need Objective Coronary Artery Disease Testing: The No Objective Testing Rule.

STUDY OBJECTIVE: We derive a clinical decision rule for ongoing investigation of patients who present to the emergency department (ED) with chest pain. The rule identifies patients who are at low risk of acute coronary syndrome and could be discharged without further cardiac testing. METHODS: This was a prospective observational study of 2,396 patients who presented to 2 EDs with chest pain suggestive of acute coronary syndrome and had normal troponin and ECG results 2 hours after presentation. Research nurses collected clinical data on presentation, and the primary endpoint was diagnosis of acute coronary syndrome within 30 days of presentation to the ED. Logistic regression analyses were conducted on 50 bootstrapped samples to identify predictors of acute coronary syndrome. A rule was derived and diagnostic accuracy statistics were computed. RESULTS: Acute coronary syndrome was diagnosed in 126 (5.3%) patients. Regression analyses identified the following predictors of acute coronary syndrome: cardiac risk factors, age, sex, previous myocardial infarction, or coronary artery disease and nitrate use. A rule was derived that identified 753 low-risk patients (31.4%), with sensitivity 97.6% (95% confidence interval [CI] 93.2% to 99.5%), negative predictive value 99.6% (95% CI 98.8% to 99.9%), specificity 33.0% (95% CI 31.1% to 35.0%), and positive predictive value 7.5% (95% CI 6.3% to 8.9%) for acute coronary syndrome. This was referred to as the no objective testing rule. CONCLUSION: We have derived a clinical decision rule for chest pain patients with negative early cardiac biomarker and ECG testing results that identifies 31% at low risk and who may not require objective testing for coronary artery disease. A prospective trial is required to confirm these findings.

Relationship Between Physiological Parameters and Acute Coronary Syndrome in Patients Presenting to the Emergency Department With Undifferentiated Chest Pain.

UNLABELLED: The investigators of this study sought to examine whether abnormal physiological parameters are associated with increased risk for acute coronary syndrome (ACS) in patients presenting to the emergency department (ED) with chest pain. METHODS: We used prospectively collected data on adult patients presenting with suspected ACS in 2 EDs in Australia and New Zealand. Trained research nurses collected physiological data including temperature, respiratory rate, heart rate, and systolic blood pressure (SBP) on presentation to the ED. The primary endpoint was ACS within 30 days of presentation, as adjudicated by cardiologists using standardized guidelines. The prognostic utility of physiological parameters for ACS was examined using risk ratios. RESULTS: Acute coronary syndrome was diagnosed in 384 of the 1951 patients (20%) recruited. Compared with patients whose SBP was between 100 and 140 mm Hg, patients with an SBP of lower than 100 mm Hg or higher than 140 mm Hg were 1.4 times (95% confidence interval, 1.2-1.7) more likely to have ACS. Similarly, compared with patients whose temperature was between 36.5°C and 37.5°C, patients with temperature of lower than 36.5°C or higher than 37.5°C were 1.4 times (95% confidence interval, 1.1-1.6) more likely to have ACS. Heart rate and respiratory rate were not predictors of ACS. CONCLUSIONS: Patients with abnormal temperature or SBP were slightly more likely to have ACS, but such risk was of too small a magnitude to be useful in clinical decision making. Other physiological parameters (heart rate and respiratory rate) had no prognostic value. The use of physiological parameters cannot reliably confirm or rule out ACS.

External validation of the emergency department assessment of chest pain score accelerated diagnostic pathway (EDACS-ADP).

OBJECTIVE: The emergency department assessment of chest pain score accelerated diagnostic pathway (EDACS-ADP) facilitates low-risk ED chest pain patients early to outpatient investigation. We aimed to validate this rule in a North American population. METHODS: We performed a retrospective validation of the EDACS-ADP using 763 chest pain patients who presented to St Paul's Hospital, Vancouver, Canada, between June 2000 and January 2003. Patients were classified as low risk if they had an EDACS <16, no new ischaemia on ECG and non-elevated serial 0-hour and 2-hour cardiac troponin concentrations. The primary outcome was the number of patients who had a predetermined major adverse cardiac event (MACE) at 30 days after presentation. RESULTS: Of the 763 patients, 317 (41.6%) were classified as low risk by the EDACS-ADP. The sensitivity, specificity, negative predictive value and positive predictive value of the EDACS-ADP for 30-day MACE were 100% (95% CI 94.2% to 100%), 46.4% (95% CI 42.6% to 50.2%), 100% (95% CI 98.5% to 100.0%) and 17.5% (95% CI 14.1% to 21.3%), respectively. CONCLUSIONS: This study validated the EDACS-ADP in a novel context and supports its safe use in a North American population. It confirms that EDACS-ADP can facilitate progression to early outpatient investigation in up to 40% of ED chest pain patients within 2 hours.

Characteristics and Clinical Course of STEMI Patients who Received no Reperfusion in the Australia and New Zealand SNAPSHOT ACS Registry.

BACKGROUND: Cohort studies of STEMI patients have reported that over 30% receive no reperfusion. Barriers to greater use of reperfusion in STEMI patients require further elucidation. METHODS: We collected data on STEMI patients with no reperfusion as part of the SNAPSHOT ACS Registry, which recruited consecutive ACS patients in 478 hospitals throughout Australia and New Zealand during 14-27 May 2012. RESULTS: Of 4387 patients enrolled, 419 were diagnosed with STEMI. Primary PCI (PPCI) was performed in 160 (38.2%), fibrinolysis was used in 105 (25.1%), and 154 (36.7%) had no reperfusion. Patients with no reperfusion had a mean age of 70.3±15.0 years compared with 63.1±13.5 in the reperfusion group (p<0.0001). There were more females in the no reperfusion group (37.1% v 23.0% p=0.002) and they were significantly more likely to have prior PCI or CABG, heart failure, atrial fibrillation, chronic kidney disease and other vascular disease, and to be nursing home residents (all p<0.05). Patients without reperfusion had a significantly higher mortality in hospital (11.7% v 4.9%, p=0.011). In 370 patients who presented within 12hours, 28 had early angiography without PCI, which was considered an attempt at reperfusion. Therefore reperfusion was attempted in 293 of 370 eligible patients (79.2%). CONCLUSION: Of consecutive STEMI patients, 36.7% did not receive any reperfusion and they had a higher risk of death in hospital. In eligible patients, reperfusion was attempted in 79.2%. National strategies to encourage earlier medical contact and greater use of reperfusion in eligible patients may lead to better outcomes.

Survival after an acute coronary syndrome: 18-month outcomes from the Australian and New Zealand SNAPSHOT ACS study.

OBJECTIVES: To assess the impact of the availability of a catheterisation laboratory and evidence-based care on the 18-month mortality rate in patients with suspected acute coronary syndromes (ACS). DESIGN, SETTING AND PARTICIPANTS: Management and outcomes are described for patients enrolled in the 2012 Australian and New Zealand SNAPSHOT ACS audit. Patients were stratified according to their presentation to hospitals with or without cardiac catheterisation facilities. Data linkage ascertained patient vital status 18 months after admission. Descriptive and Cox proportional hazards analyses determined predictors of outcomes, and were used to estimate the numbers of deaths that could be averted by improved application of evidence-based care. MAIN OUTCOME MEASURES: Mortality for ACS patients from admission to 18 months after admission. RESULTS: Definite ACS patients presenting to catheterisation-capable (CC) hospitals (n = 1326) were more likely to undergo coronary angiography than those presenting to non-CC hospitals (n = 1031) (61.5% v 50.8%; P = 0.0001), receive timely reperfusion (for ST elevation myocardial infarction (STEMI) patients: 45.2% v 19.2%; P < 0.001), and be referred for cardiac rehabilitation (57% v 53%; P = 0.05). All-cause mortality over 18 months was highest for STEMI (16.2%) and non-STEMI (16.3%) patients, and lowest for those presenting with unstable angina (6.8%) and non-cardiac chest pain (4.8%; P < 0.0001 for trend). After adjustment for patient propensity to present to a CC hospital and patient risk, presentation to a CC hospital was associated with 21% (95% CI, 2%-37%) lower mortality than presentation to a non-CC hospital. This mortality difference was attenuated after adjusting for delivery of evidence-based care. CONCLUSION: In Australia and New Zealand, the availability of a catheterisation laboratory appears to have a significant impact on long-term mortality in ACS patients, which is still substantial. This mortality may be reduced by improvements in evidence-based care in both CC and non-CC hospitals.

Availability of highly sensitive troponin assays and acute coronary syndrome care: insights from the SNAPSHOT registry.

OBJECTIVES: To examine differences in care and inhospital course of patients with possible acute coronary syndrome (ACS) in Australia and New Zealand based on whether a highly sensitive (hs) troponin assay was used at the hospital to which they presented. DESIGN, SETTING AND PATIENTS: A snapshot study of consecutive patients presenting to hospitals in Australia and New Zealand from 14 to 27 May 2012 with possible ACS. MAIN OUTCOME MEASURES: Rates of major adverse cardiac events (inhospital death, new or recurrent myocardial infarction, stroke, cardiac arrest or worsening heart failure); association between assay type and outcome (via propensity score matching and a generalised estimating equation [GEE]; averages of the predicted outcomes among patients who were treated with and without the availability of an hs assay (via inverse probability-weighting [IPW] with regression-adjusted estimators). RESULTS: 4371 patients with possible ACS were admitted to 283 hospitals. Over half of the hospitals (156 [55%]) reported using the hs assay and most patients (2624 [60%]) had hs tests (P = 0.004). Use of the hs assay was independent of hospital coronary revascularisation capability. Patients tested with the hs assay had more non-invasive investigations (exercise tests, stress echocardiography, stress nuclear scans, and computed tomography coronary angiography) than those tested with the sensitive assay. However, there were no differences between the groups in rates of angiography or revascularisation. All adjusted analyses showed a consistently lower rate of inhospital events, including recurrent heart failure in patients for whom the hs assay was used (GEE odds ratio, 0.75; 95% CI, 0.60-0.94; P = 0.014); IPW analysis showed a 2.3% absolute reduction in these events with the use of the hs assay (P = 0.018). CONCLUSION: Use of hs troponin testing of patients hospitalised with possible ACS was associated with an increased rate of non-invasive cardiac investigations and fewer inhospital adverse events.

Cost and outcomes of assessing patients with chest pain in an Australian emergency department.

OBJECTIVES: We sought to characterise the demographics, length of admission, final diagnoses, long-term outcome and costs associated with the population who presented to an Australian emergency department (ED) with symptoms of possible acute coronary syndrome (ACS). DESIGN, SETTING AND PARTICIPANTS: Prospectively collected data on ED patients presenting with suspected ACS between November 2008 and February 2011 was used, including data on presentation and at 30 days after presentation. Information on patient disposition, length of stay and costs incurred was extracted from hospital administration records. MAIN OUTCOME MEASURES: Primary outcomes were mean and median cost and length of hospital stay. Secondary outcomes were diagnosis of ACS, other cardiovascular conditions or non-cardiovascular conditions within 30 days of presentation. RESULTS: An ACS was diagnosed in 103 (11.1%) of the 926 patients recruited. 193 patients (20.8%) were diagnosed with other cardiovascular-related conditions and 622 patients (67.2%) had non-cardiac-related chest pain. ACS events occurred in 0 and 11 (1.9%) of the low-risk and intermediate-risk groups, respectively. Ninety-two (28.0%) of the 329 high-risk patients had an ACS event. Patients with a proven ACS, high-grade atrioventricular block, pulmonary embolism and other respiratory conditions had the longest length of stay. The mean cost was highest in the ACS group ($13 509; 95% CI, $11 794-$15 223) followed by other cardiovascular conditions ($7283; 95% CI, $6152-$8415) and non-cardiovascular conditions ($3331; 95% CI, $2976-$3685). CONCLUSIONS: Most ED patients with symptoms of possible ACS do not have a cardiac cause for their presentation. The current guideline-based process of assessment is lengthy, costly and consumes significant resources. Investigation of strategies to shorten this process or reduce the need for objective cardiac testing in patients at intermediate risk according to the National Heart Foundation and Cardiac Society of Australia and New Zealand guideline is required.

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.

Should fee-for-service be for all guideline-advocated acute coronary syndrome (ACS) care? Observations from the Snapshot ACS study.

OBJECTIVE: The aim of the present study was to explore the association of health insurance status on the provision of guideline-advocated acute coronary syndrome (ACS) care in Australia. METHODS: Consecutive hospitalisations of suspected ACS from 14 to 27 May 2012 enrolled in the Snapshot study of Australian and New Zealand patients were evaluated. Descriptive and logistic regression analysis was performed to evaluate the association of patient risk and insurance status with the receipt of care. RESULTS: In all, 3391 patients with suspected ACS from 247 hospitals (23 private) were enrolled in the present study. One-third of patients declared private insurance coverage; of these, 27.9% (304/1088) presented to private facilities. Compared with public patients, privately insured patients were more likely to undergo in-patient echocardiography and receive early angiography; furthermore, in those with a discharge diagnosis of ACS, there was a higher rate of revascularisation (P < 0.001). Each of these attracts potential fee-for-service. In contrast, proportionately fewer privately insured ACS patients were discharged on selected guideline therapies and were referred to a secondary prevention program (P = 0.056), neither of which directly attracts a fee. Typically, as GRACE (the Global Registry of Acute Coronary Events) risk score rose, so did the level of ACS care; however, propensity-adjusted analyses showed lower in-hospital adverse events among the insured group (odds ratio 0.68; 95% confidence interval 0.52-0.88; P = 0.004). CONCLUSION: Fee-for-service reimbursement may explain differences in the provision of selected guideline-advocated components of ACS care between privately insured and public patients.