Management of Acute Coronary Syndromes in Patients in Rural Australia: The MORACS Randomized Clinical Trial

Importance

Treatment of ST-segment elevation myocardial infarction (STEMI) in rural settings involves thrombolysis followed by transfer to a percutaneous coronary intervention-capable hospital. The first step is accurate diagnosis via electrocardiography (ECG), but one-third of all STEMI incidents go unrecognized and hence untreated.

Objective

To reduce missed diagnoses of STEMI.

Design, Setting, and Participants

This cluster randomized clinical trial included 29 hospital emergency departments (EDs) in rural Australia with no emergency medicine specialists, which were randomized to usual care vs automatically triggered diagnostic support from the tertiary referral hospital (management of rural acute coronary syndromes [MORACS] intervention). Patients presenting with symptoms compatible with acute coronary syndromes (ACS) were eligible for inclusion. The study was conducted from December 2018 to April 2020. Data were analyzed in August 2021.

Intervention

Triage of a patient with symptoms compatible with ACS triggered an automated notification to the tertiary hospital coronary care unit. The ECG and point-of-care troponin results were reviewed remotely and a phone call was made to the treating physician in the rural hospital to assist with diagnosis and initiation of treatment.

Main Outcomes and Measures

The proportion of patients with missed STEMI diagnoses.

Results

A total of 6249 patients were included in the study (mean [SD] age, 63.6 [12.2] years; 48% female). Of 7474 ED presentations with suspected ACS, STEMI accounted for 77 (2.0%) in usual care hospitals and 46 (1.3%) in MORACS hospitals. Missed diagnosis of STEMI occurred in 27 of 77 presentations (35%) in usual care hospitals and 0 of 46 (0%) in MORACS hospitals (P < .001). Of eligible patients, 48 of 75 (64%) in the usual care group and 36 of 36 (100%) in the MORACS group received primary reperfusion (P < .001). In the usual care group, 12-month mortality was 10.3% (n = 8) vs 6.5% (n = 3) in the MORACS group (relative risk, 0.64; 95% CI, 0.18-2.23). Patients with missed STEMI diagnoses had a mortality of 25.9% (n = 7) compared with 2.0% (n = 1) for those with accurately diagnosed STEMI (relative risk, 13.2; 95% CI, 1.71-102.00; P = .001). Overall, there were 6 patients who did not have STEMI as a final diagnosis; 5 had takotsubo cardiomyopathy and 1 had pericarditis. There was no difference between groups in the rate of alternative final diagnosis.

Conclusion and Relevance

The findings indicate that MORACS diagnostic support service reduced the proportion of missed STEMI and improved the rates of primary reperfusion therapy. Accurate diagnosis of STEMI was associated with lower mortality.

Trial Registration

anzctr.org.au Identifier: ACTRN12619000533190.

Not All STEMI Patients Receive Timely Reperfusion: Considerations for Rural Emergency Departments

Early reperfusion for ST-elevation myocardial infarction (STEMI) is well known to improve patient outcomes. A review of patient records in one rural health service in New South Wales, Australia, suggested that not all STEMI patients were receiving timely reperfusion. Consequently, the aim of this study was to further investigate factors influencing clinical decision making by primary care providers in relation to rural STEMI patients. This cross-sectional observational study was in two phases, a retrospective audit of patient records and a survey of rural general practitioners (GPs). In the first phase, patients with STEMI who were referred from small rural hospitals to a regional hospital emergency department (ED) were identified through the local health district database. In phase two, information from the database informed questions for a survey distributed to the GP visiting medical officers (VMOs) at small rural hospitals in the region. The survey was designed to ascertain factors that may contribute to delays in the care of STEMI patients. Of the STEMI patients identified (n = 139), 15% (21) who were eligible for medical reperfusion were not administered thrombolysis within 4 hours of triage. Auditing of this group's records found that ECGs were inaccurately interpreted for 76% of the missed STEMI patients. In the survey, about 55% of the GP respondents said they “very much agree” with the statement that they felt competent in STEMI management. Only 64% of the GP VMOs agreed they felt competent in diagnosis and management of a failed thrombolysis and not all respondents were aware of the relevant clinical guideline. Patients with missed STEMI are at higher risk of morbidity and mortality and increased length of stay, adding burden to the patient, carer and health service. Without addressing gaps in service provision and better adherence to clinical guidelines, unacceptable delays in STEMI management in rural health services are likely to continue.

Missed Acute Myocardial Infarction (MAMI) in a rural and regional setting

Background

Delay in treatment and/or failure to provide reperfusion in ST-segment elevation myocardial infarction (STEMI) impacts on morbidity and mortality. This occurs more often outside metropolitan areas yet the reasons for this are unclear. This study aimed to describe factors associated with missed diagnosis of acute myocardial infarction (MAMI) in a rural and regional setting.

Methods

Using a retrospective cohort design, patients who presented with STEMI and failed to receive reperfusion therapy within four hours were identified as MAMI. Univariate analyses were undertaken to identify differences in clinical characteristics between the treated STEMI group and the MAMI group. Mortality, 30-day readmission rates and length of hospital stay are reported.

Results

Of 100 patients identified as MAMI (70 male, 30 female), 24 died in hospital. Demographics and time from symptom onset were similar in the treated STEMI and MAMI groups. Of the MAMI patients who died, rural hospitals recorded the highest inpatient mortality (69.6% p = 0.008). MAMI patients compared to treated STEMI patients had higher 30 day readmission (31.6% vs 3.3%, p = 0.001) and longer length of stay (5.5 vs 4.3 days p = 0.029). Inaccurate identification of STEMI on electrocardiogram (72%) and diagnostic uncertainty (65%) were associated with MAMI. The Glasgow algorithm to identify STEMI was utilised on 57% of occasions, with 93% accuracy.

Conclusion

Mortality following MAMI is high particularly in smaller rural hospitals. MAMI results in increased length of stay and readmission rate. Electrocardiogram interpretation and diagnostic accuracy require improvement to determine if this improves patient outcomes.