The barriers associated with emergency medical service use for acute coronary syndrome: the awareness and influence of an Australian public mass media campaign

A protocol for the Heart Matters stepped wedge cluster randomised trial: The effectiveness of heart attack education in regions at highest-risk

AIM

To describe the Heart Matters (HM) trial which aims to evaluate the effectiveness of a community heart attack education intervention in high-risk areas in Victoria, Australia. These local government areas (LGAs) have high rates of acute coronary syndrome (ACS), out-of-hospital cardiac arrest (OHCA), cardiovascular risk factors, and low rates of emergency medical service (EMS) use for ACS.

METHODS

The trial follows a stepped-wedge cluster randomised design, with eight clusters (high-risk LGAs) randomly assigned to transition from control to intervention every four months. Two pairs of LGAs will transition simultaneously due to their proximity. The intervention consists of a heart attack education program delivered by trained HM Coordinators, with additional support from opportunistic media and a geo-targeted social media campaign. The primary outcome measure is the proportion of residents from the eight LGAs who present to emergency departments by EMS during an ACS event. Secondary outcomes include prehospital delay time, rates of OHCA and heart attack awareness. The primary and secondary outcomes will be analysed at the patient/participant level using mixed-effects logistic regression models. A detailed program evaluation is also being conducted. The trial was registered on August 9, 2021 (NCT04995900).

RESULTS

The intervention was implemented between February 2022 and March 2023, and outcome data will be collected from administrative databases, registries, and surveys. Primary trial data is expected to be locked for analysis by October 31st 2023, with a follow-up planned until March 31st 2024.

CONCLUSION

The results from this trial will provide high-level evidence the effectiveness of a community education intervention targeting regions at highest-risk of ACS and low EMS use.

Association of Symptoms and Mode of Transportation to Emergency Department in Patients With Acute Coronary Syndrome

BACKGROUND

Patients with acute coronary syndrome (ACS) with symptoms matching their expectations of a heart attack are more likely to use emergency medical services (EMS) than not.

OBJECTIVE

To determine whether presenting symptom clusters are associated with EMS use in ACS patients and if EMS use or symptom clusters are associated with prehospital delay.

METHODS

This secondary analysis used data from the PROMOTION trial, a randomized clinical trial that enrolled 3522 subjects with a history of or at risk for ACS from 5 sites in the United States, Australia, and New Zealand. Subjects were randomized to usual care or an educational intervention to reduce prehospital delay. During the 2-year follow-up, subjects admitted for ACS were asked about symptoms, time of symptom onset, and mode of transportation to the hospital. Symptoms were grouped into classic ACS, pain symptoms, and stress symptoms clusters.

RESULTS

Of 3522 subjects enrolled, 331 sought care for ACS during follow-up; 278 had transportation mode documented; 121 (44%) arrived via EMS. Classic ACS plus pain symptoms (adjusted odds ratio [AOR], 2.66; P = .011), classic ACS plus stress symptoms (AOR, 2.61; P = .007), and classic ACS plus both pain and stress symptoms (AOR, 3.90; P = .012) were associated with higher odds of EMS use versus classic ACS symptoms alone. Emergency medical services use resulted in a 68.5-minute shorter median delay (P = .002) versus non-EMS use. Symptom clusters were not predictive of delay time in the adjusted model (P = .952).

DISCUSSION

Although chest symptoms were the most prevalent symptoms for most (85%), the combination of classic ACS symptoms with other symptom clusters was associated with higher EMS use. Further research is needed to determine whether a combination of symptom clusters helps patients correctly interpret ACS symptoms to better understand how symptom clusters influence EMS use.

Barriers associated with emergency medical service activation in patients with ST-segment elevation acute coronary syndromes

Many ST-segment elevation acute coronary syndrome (STEACS) patients fail to activate the Emergency Medical System (EMS), with possible dramatic consequences. Prior studies focusing on barriers to EMS activation included patients with any acute coronary syndrome (ACS) without representation of southern European populations. We aimed to investigate the barriers to EMS call for patients diagnosed for STEACS in Italy. A prospective, single-center, survey administered to all patients treated with primary percutaneous coronary intervention for STEACS in a tertiary hospital in northern Italy from 01/06/2018 to 31/05/2020. The questionnaire was filled out by 293 patients. Of these, 191 (65.2%) activated the EMS after symptoms onset. The main reasons for failing to contact EMS were the perception that the symptoms were unrelated to an important health problem (45.5%) and that a private vehicle is faster than EMS to reach the hospital (34.7%). Patients who called a private doctor after symptoms onset did not call EMS more frequently than those who did not and 30% of the patients who did not call the EMS would still act in the same way if a new episode occurred. Previous history of cardiovascular disease was the only predictor of EMS call. Information campaigns are urgently needed to increase EMS activation in case of suspected STEACS and should be primary focused on patients without cardiovascular history, on the misperception that a private vehicle is faster than EMS activation, and on the fact that cardiac arrest occurs early and may be prevented by EMS activation.

The potential of new prediction models for emergency medical dispatch prioritisation of patients with chest pain: a cohort study

Objectives

To develop emergency medical dispatch (EMD) centre prediction models with high sensitivity and satisfying specificity to identify high-priority patients and patients suitable for non-emergency care respectively, when assessing patients with chest pain.

Methods

Observational cohort study of 2917 unselected patients with chest pain who contacted an EMD centre in Sweden due to chest pain during 2018. Multivariate logistic regression was applied to develop models predicting low-risk or high-risk condition, that is, occurrence of time-sensitive diagnosis on hospital discharge.

Results

Prediction models were developed for the identification of patients suitable for high- and low-priority dispatch, using 11 and 10 variables respectively. The area under the receiver-operating characteristic curve (AUROC) for the high-risk prediction model was 0.79 and for the low-risk model it was 0.74. When applying the high-risk prediction model, 56% of the EMS missions were given highest priority, compared with 65% with the current standard. When applying the low-risk model, 7% were given the lowest priority compared to 1% for the current standard. The new prediction models outperformed today’s dispatch priority accuracy in terms of sensitivity as well as positive and negative predictive value in both high- and low-risk prediction. The low-risk model predicted almost six times as many patients as having low-risk conditions compared with today’s standard. This was done without increasing the number of high-risk patients wrongly assessed as low-risk.

Conclusions

By introducing prediction models, based on logistic regression analyses, using variables obtained by standard EMD-questions on age, sex, medical history and symptomology, EMD prioritisation can be improved compared with using current criteria index-based ones. This will allow a more efficient emergency medical services resource allocation.

Impact of a mass media campaign on presentations and ambulance use for acute coronary syndrome

Objective

Between 2009 and 2013, the National Heart Foundation of Australia ran mass media campaigns to improve Australian’s awareness of acute coronary syndrome (ACS) symptoms and the need to call emergency medical services (EMS). This study examined the impact of this campaign on emergency department (ED) presentations and EMS use in Victoria, Australia.

Methods

The Victorian Department of Health and Human Services provided data for adult Victorian patients presenting to public hospitals with an ED diagnosis of ACS or unspecified chest pain (U-CP). We modelled changes in the incidence of ED presentations, and the association between the campaign period and (1) EMS arrival and (2) referred to ED by a general practitioner (GP). Models were adjusted for increasing population size, ACS subtype and demographics.

Results

Between 2003 and 2015, there were 124 632 eligible ED presentations with ACS and 536 148 with U-CP. In patients with ACS, the campaign period was associated with an increase in ED presentations (incidence rate ratio: 1.11; 95% CI 1.07 to 1.15), a decrease in presentations via a GP (adjusted OR (AOR): 0.77; 95% CI 0.70 to 0.86) and an increase in EMS use (AOR: 1.10; 95% CI 1.05 to 1.17). Similar, but smaller associations were seen in U-CP.

Conclusions

The Warning Signs Campaign was associated with improvements in treatment seeking in patients with ACS—including increased EMS use. The increase in ACS ED presentations corresponds with a decrease in out-of-hospital cardiac arrest over this time. Future education needs to focus on improving EMS use in ACS patient groups where use remains low.