Acute rule-out of non-ST-segment elevation acute coronary syndrome in the (pre)hospital setting by HEART score assessment and a single point-of-care troponin: rationale and design of the ARTICA randomised trial

Pre-hospital rule-out of non-ST-segment elevation acute coronary syndrome by a single troponin: final one-year outcomes of the ARTICA randomised trial

BACKGROUND AND AIMS

The healthcare burden of acute chest pain is enormous. In the randomized ARTICA trial, we showed that pre-hospital identification of low-risk patients and rule-out of non-ST-segment elevation acute coronary syndrome (NSTE-ACS) with point-of-care (POC) troponin measurement reduces 30-day healthcare costs with low major adverse cardiac events (MACE) incidence. Here we present the final 1-year results of the ARTICA trial.

METHODS

Low-risk patients with suspected NSTE-ACS were randomized to pre-hospital rule-out with POC troponin measurement or emergency department (ED) transfer. Primary 1-year outcome was healthcare costs. Secondary outcomes were safety, quality of life (QoL), and cost-effectiveness. Safety was defined as a 1-year MACE consisting of ACS, unplanned revascularization, or all-cause death. QoL was measured with EuroQol-5D-5L questionnaires. Cost-effectiveness was defined as 1-year healthcare costs difference per QoL difference.

RESULTS

Follow-up was completed for all 863 patients. Healthcare costs were significantly lower in the pre-hospital strategy (€1932 ± €2784 vs. €2649 ± €2750), mean difference €717 [95% confidence interval (CI) €347 to €1087; P < 0.001]. In the total population, the 1-year MACE rate was comparable between groups [5.1% (22/434) in the pre-hospital strategy vs. 4.2% (18/429) in the ED strategy; P = 0.54]. In the ruled-out ACS population, 1-year MACE remained low [1.7% (7/419) vs. 1.4% (6/417)], risk difference 0.2% (95% CI -1.4% to 1.9%; P = 0.79). QoL showed no significant difference between strategies.

CONCLUSIONS

Pre-hospital rule-out of NSTE-ACS with POC troponin testing in low-risk patients is cost-effective, as expressed by a sustainable healthcare cost reduction and no significant effect on QoL. One-year MACE remained low for both strategies.

Pre-hospital admission of heparin in patients with suspected non-ST segment elevation acute coronary syndrome

BACKGROUND

Evidence supporting pre-hospital heparin administration in patients with suspected non-ST segment elevation acute coronary syndrome (NSTE-ACS) is lacking. We aim to evaluate if pre-hospital heparin administration by emergency medical service improves clinical outcome in patients with suspected NSTE-ACS.

METHODS

Patients with suspected myocardial infarction (MI) presenting to the emergency department were prospectively enrolled from 2013 to 2021, excluding those with ST segment elevation MI. Patients with and without prehospital heparin administration were compared using propensity score matching. To assess the association between pre-hospital heparin loading, 30-day and 1-year mortality, Kaplan-Meier estimations and Cox regression models were used.

RESULTS

Among 1,234 patients, median age was 69 years, 755 (61.2%) were male, 867 (70.5%) with known hypertension, 177 (14.4%) had diabetes, 280 (23.1%) were current smokers, and 444 (36.0%) had a history of CAD. Compared to patients without pre-hospital heparin administration, heparin pre-treated patients were more often active smokers (26.5% vs. 20.8%). After propensity matching, 475 patients with vs. without pre-hospital heparin administration were compared, with no significant difference in 30-day mortality (no-heparin 1.3% vs. heparin 0.4%) and 1-year mortality (no-heparin 7.2% vs. heparin 5.5%, adjusted HR 0.98, CI 0.95-1.01, p = 0.22). Bleeding events occurred at a low frequency (< 2%) and did not differ between groups.

CONCLUSIONS

In this study, pre-hospital heparin administration was not associated with improved clinical outcome in patients with suspected NSTE-ACS. These findings question pre-hospital heparin therapy in this patient population and might potentially warrant a more restricted utilization pending in-hospital risk assessment.

Pre-hospital evaluation of chest pain patients using the modified HEART-score: rationale and design

Background: This study assesses how ambulance paramedics using the modified HEART-score with a point-of-care cardiac troponin (cTn) compare to the emergency physicians using the modified HEART-score with a high-sensitive cTn (hs-cTn) in patients with suspected non-ST-elevation acute coronary syndrome (NSTE-ACS), focusing on interobserver agreement and diagnostic performance. Methods: In this prospective multicenter cohort, we compare four cTn testing strategies (serial point of care and hs-cTn cTn measurement) with and without the HEART-score. Outcomes include the HEART-score's interobserver agreement, NSTE-ACS at discharge, major adverse cardiovascular events (MACE) after 30 days, and diagnostic accuracy of the different strategies. Conclusion: The POPular HEART study aims to improve NSTE-ACS diagnostic pathways, promoting pre-hospital detection and ruling out of NSTE-ACS to minimize unnecessary hospitalizations and associated costs.Clinical Trial Registration: NCT04851418 (ClinicalTrials.gov).

High-Sensitivity Cardiac Troponin Assays: Ready for Prime Time!

Rapid and accurate triage of patients presenting with chest pain to an emergency department (ED) is critical to prevent ED overcrowding and unnecessary resource use in individuals at low risk of acute myocardial infarction (AMI) and to efficiently and effectively guide patients at high risk to definite therapy. The use of biomarkers for rule-out or rule-in of suspected AMI has evolved substantially over the last several decades. Previously well-established biomarkers have been replaced by cardiac troponin (cTn). High-sensitivity cTn (hs-cTn) assays represent the newest generation of cTn assays and offer tremendous advantages, including improved sensitivity and precision. Still, implementation of these assays in the United States lags behind several other areas of the world. Within this educational review, we discuss the evolution of biomarker testing for detection of myocardial injury, address the specifics of hs-cTn assays and their recommended use within triage algorithms, and highlight potential challenges in their use. Ultimately, we focus on implementation strategies for hs-cTn assays, as they are now clearly ready for prime time.

Differences in risk and costs between prehospital identified low-risk men and women with chest pain

OBJECTIVE

Prehospital rule-out of non-ST-segment elevation acute coronary syndrome (NSTE-ACS) in low-risk patient with a point-of-care troponin measurement reduces healthcare costs with similar safety to standard transfer to the hospital. Risk stratification is performed identical for men and women, despite important differences in clinical presentation, risk factors and age between men and women with NSTE-ACS. Our aim was to compare safety and healthcare costs between men and women in prehospital identified low-risk patients with suspected NSTE-ACS.

METHODS

In the Acute Rule-out of non-ST-segment elevation acute coronary syndrome in the (pre)hospital setting by HEART (History, ECG, Age, Risk factors and Troponin) score assessment and a single poInt of CAre troponin randomised trial, the HEAR (History, ECG, Age and Risk factors) score was assessed by ambulance paramedics in suspected NSTE-ACS patients. Low-risk patients (HEAR score ≤3) were included. In this substudy, men and women were compared. Primary endpoint was 30-day major adverse cardiac events (MACE), secondary endpoints were 30-day healthcare costs and the scores for the HEAR score components.

RESULTS

A total of 863 patients were included, of which 495 (57.4%) were women. Follow-up was completed in all patients. In the total population, MACE occurred in 6.8% of the men and 1.6% of the women (risk ratio (RR) 4.2 (95% CI 1.9 to 9.2, p<0.001)). In patients with ruled-out ACS (97% of the total population), MACE occurred in 1.4% of the men and in 0.2% of the women (RR 7.0 (95% CI 2.0 to 14.2, p<0.001). Mean healthcare costs were €504.55 (95% CI €242.22 to €766.87, p<0.001) higher in men, mainly related to MACE.

CONCLUSIONS

In a prehospital population of low-risk suspected NSTE-ACS patients, 30-day incidence of MACE and MACE-related healthcare costs were significantly higher in men than in women.

TRIAL REGISTRATION NUMBER

NCT05466591.

AI Algorithm to Predict Acute Coronary Syndrome in Prehospital Cardiac Care: Retrospective Cohort Study

BACKGROUND

Overcrowding of hospitals and emergency departments (EDs) is a growing problem. However, not all ED consultations are necessary. For example, 80% of patients in the ED with chest pain do not have an acute coronary syndrome (ACS). Artificial intelligence (AI) is useful in analyzing (medical) data, and might aid health care workers in prehospital clinical decision-making before patients are presented to the hospital.

OBJECTIVE

The aim of this study was to develop an AI model which would be able to predict ACS before patients visit the ED. The model retrospectively analyzed prehospital data acquired by emergency medical services' nurse paramedics.

METHODS

Patients presenting to the emergency medical services with symptoms suggestive of ACS between September 2018 and September 2020 were included. An AI model using a supervised text classification algorithm was developed to analyze data. Data were analyzed for all 7458 patients (mean 68, SD 15 years, 54% men). Specificity, sensitivity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for control and intervention groups. At first, a machine learning (ML) algorithm (or model) was chosen; afterward, the features needed were selected and then the model was tested and improved using iterative evaluation and in a further step through hyperparameter tuning. Finally, a method was selected to explain the final AI model.

RESULTS

The AI model had a specificity of 11% and a sensitivity of 99.5% whereas usual care had a specificity of 1% and a sensitivity of 99.5%. The PPV of the AI model was 15% and the NPV was 99%. The PPV of usual care was 13% and the NPV was 94%.

CONCLUSIONS

The AI model was able to predict ACS based on retrospective data from the prehospital setting. It led to an increase in specificity (from 1% to 11%) and NPV (from 94% to 99%) when compared to usual care, with a similar sensitivity. Due to the retrospective nature of this study and the singular focus on ACS it should be seen as a proof-of-concept. Other (possibly life-threatening) diagnoses were not analyzed. Future prospective validation is necessary before implementation.

Management of patients suspected for non-ST elevation-acute coronary syndrome in the prehospital phase

The management of patients with suspected acute coronary syndrome, especially in prehospital settings, is challenging. This Special Report focuses on studies in emergency medical services concerning chest pain patients' triage and risk stratification. In addition, it emphasizes advancements in point-of-care cardiac troponin testing. These developments are compared with in-hospital guidelines, proposing an initial framework for a new acute care pathway. This pathway integrates a risk stratification tool with high-sensitivity cardiac troponin testing, aiming to deliver optimal care and collaboration within the acute care chain. It has the potential to contribute to a significant reduction in hospital referrals, reduce observation time and overcrowding at emergency departments and hospital admissions.

Performance of a prehospital HEART score in patients with possible myocardial infarction: a prospective evaluation

INTRODUCTION

The History, Electrocardiogram (ECG), Age, Risk Factors and Troponin (HEART) score is commonly used to risk stratify patients with possible myocardial infarction as low risk or high risk in the Emergency Department (ED). Whether the HEART score can be used by paramedics to guide care were high-sensitivity cardiac troponin testing available in a prehospital setting is uncertain.

METHODS

In a prespecified secondary analysis of a prospective cohort study where paramedics enrolled patients with suspected myocardial infarction, a paramedic Heart, ECG, Age, Risk Factors (HEAR) score was recorded contemporaneously, and a prehospital blood sample was obtained for subsequent cardiac troponin testing. HEART and modified HEART scores were derived using laboratory contemporary and high-sensitivity cardiac troponin I assays. HEART and modified HEART scores of ≤3 and ≥7 were applied to define low-risk and high-risk patients, and performance was evaluated for an outcome of major adverse cardiac events (MACEs) at 30 days.

RESULTS

Between November 2014 and April 2018, 1054 patients were recruited, of whom 960 (mean 64 (SD 15) years, 42% women) were eligible for analysis and 255 (26%) experienced a MACE at 30 days. A HEART score of ≤3 identified 279 (29%) as low risk with a negative predictive value of 93.5% (95% CI 90.0% to 95.9%) for the contemporary assay and 91.4% (95% CI 87.5% to 94.2%) for the high-sensitivity assay. A modified HEART score of ≤3 using the limit of detection of the high-sensitivity assay identified 194 (20%) patients as low risk with a negative predictive value of 95.9% (95% CI 92.1% to 97.9%). A HEART score of ≥7 using either assay gave a lower positive predictive value than using the upper reference limit of either cardiac troponin assay alone.

CONCLUSIONS

A HEART score derived by paramedics in the prehospital setting, even when modified to harness the precision of a high-sensitivity assay, does not allow safe rule-out of myocardial infarction or enhanced rule-in compared with cardiac troponin testing alone.

Acute Chest Pain—Diagnostic Accuracy and Pre-Hospital Use of Anticoagulants and Platelet Aggregation Inhibitors

BACKGROUND

Acute chest pain (aCP) can be a symptom of life-threatening diseases such as acute coronary or aortic syndrome, but often has a non-cardiac cause. The recommendations regarding pre-hospital drug treatment of patients with aCP are ambiguous.

METHODS

A retrospective cohort study was conducted of 822 patients with aCP who were attended by emergency physicians. The cause of aCP was classified as follows: acute coronary syndrome without ST-segment elevation (NSTE-ACS), acute aortic syndrome, hypertensive crisis, cardiac arrhythmias, musculoskeletal, or other. The suspected and discharge diagnoses were compared, and the pre-hospital administration of acetylsalicylic acid (ASA) and unfractionated heparin (UFH) was analyzed. Furthermore, the parameters that improved diagnostic accuracy were investigated.

RESULTS

The positive predictive value of the diagnosis assigned by the emergency physician (EP diagnosis) was 39.7%. NSTEACS was the most commonly suspected cause of aCP (74.7%), but was confirmed after hospital admission in only 26.3% of patients. ASA was administered in 51%, UFH in 55%, and both substances in 46.4% of cases. A large proportion of patients received anticoagulants in the pre-hospital setting although the discharge diagnosis was not NSTE-ACS: ASA 62.9%, UFH 66.0%, both substances 56.5%.

CONCLUSION

ASA and UFH are often given to EP-accompanied patients with aCP despite the low accuracy of diagnosis in the pre-hospital setting. Pre-hospital measurement of high-sensitivity troponin T (hs Trop-T) might improve discrimination between NSTE-ACS and other causes of aCP. This is important, as the current guidelines contain no clear recommendations for prehospital drug treatment in NSTE-ACS.

Improved prehospital triage for acute cardiac care: results from HART-c, a multicentre prospective study

BACKGROUND

Cardiac symptoms are one of the most prevalent reasons for emergency department visits. However, over 80% of patients with such symptoms are sent home after acute cardiovascular disease has been ruled out.

OBJECTIVE

The Hollands-Midden Acute Regional Triage-cardiology (HART-c) study aimed to investigate whether a novel prehospital triage method, combining prehospital and hospital data with expert consultation, could increase the number of patients who could safely stay at home after emergency medical service (EMS) consultation.

METHODS

The triage method combined prehospital EMS data, such as electrocardiographic and vital parameters in real time, and data from regional hospitals (including previous medical records and admission capacity) with expert consultation. During the 6‑month intervention and control periods 1536 and 1376 patients, respectively, were consulted by the EMS. The primary endpoint was the percentage change of patients who could stay at home after EMS consultation.

RESULTS

The novel triage method led to a significant increase in patients who could safely stay at home, 11.8% in the intervention group versus 5.9% in the control group: odds ratio 2.31 (95% confidence interval (CI) 1.74-3.05). Of 181 patients staying at home, only 1 (< 1%) was later diagnosed with ACS; no patients died. Furthermore the number of interhospital transfers decreased: relative risk 0.81 (95% CI 0.67-0.97).

CONCLUSION

The HART‑c triage method led to a significant decrease in interhospital transfers and an increase in patients with cardiac symptoms who could safely stay at home. The presented method thereby reduced overcrowding and, if implemented throughout the country and for other medical specialties, could potentially reduce the number of cardiac and non-cardiac hospital visits even further.

Healthcare cost burden of acute chest pain presentations

BACKGROUND

This study aimed to estimate the direct healthcare cost burden of acute chest pain attendances presenting to ambulance in Victoria, Australia, and to identify key cost drivers especially among low-risk patients.

METHODS

State-wide population-based cohort study of consecutive adult patients attended by ambulance for acute chest pain with individual linkage to emergency and hospital admission data in Victoria, Australia (1 January 2015-30 June 2019). Direct healthcare costs, adjusted for inflation to 2020-2021 ($A), were estimated for each component of care using a casemix funding method.

RESULTS

From 241 627 ambulance attendances for chest pain during the study period, mean chest pain episode cost was $6284, and total annual costs were estimated at $337.4 million ($68 per capita per annum). Total annual costs increased across the period ($310.5 million in 2015 vs $384.5 million in 2019), while mean episode costs remained stable. Cardiovascular conditions (25% of presentations) were the most expensive (mean $11 523, total annual $148.7 million), while a non-specific pain diagnosis (49% of presentations) was the least expensive (mean $3836, total annual $93.4 million). Patients classified as being at low risk of myocardial infarction, mortality or hospital admission (Early Chest pain Admission, Myocardial infarction, and Mortality (ECAMM) score) represented 31%-57% of the cohort, with total annual costs estimated at $60.6 million-$135.4 million, depending on the score cut-off used.

CONCLUSIONS

Total annual costs for acute chest pain presentations are increasing, and a significant proportion of the cost burden relates to low-risk patients and non-specific pain. These data highlight the need to improve the cost-efficiency of chest pain care pathways.

Chest Pain Management Using Prehospital Point-of-Care Troponin and Paramedic Risk Assessment

Importance

Prehospital point-of-care troponin testing and paramedic risk stratification might improve the efficiency of chest pain care pathways compared with existing processes with equivalent health outcomes, but the association with health care costs is unclear.

Objective

To analyze whether prehospital point-of-care troponin testing and paramedic risk stratification could result in cost savings compared with existing chest pain care pathways.

Design, Setting, and Participants

In this economic evaluation of adults with acute chest pain without ST-segment elevation, cost-minimization analysis was used to assess linked ambulance, emergency, and hospital attendance in the state of Victoria, Australia, between January 1, 2015, and June 30, 2019.

Interventions

Paramedic risk stratification and point-of-care troponin testing.

Main Outcomes and Measures

The outcome was estimated mean annualized statewide costs for acute chest pain. Between May 17 and June 25, 2022, decision tree models were developed to estimate costs under 3 pathways: (1) existing care, (2) paramedic risk stratification and point-of-care troponin testing without prehospital discharge, or (3) prehospital discharge and referral to a virtual emergency department (ED) for low-risk patients. Probabilities for the prehospital pathways were derived from a review of the literature. Multivariable probabilistic sensitivity analysis with 50 000 Monte Carlo iterations was used to estimate mean costs and cost differences among pathways.

Results

A total of 188 551 patients attended by ambulance for chest pain (mean [SD] age, 61.9 [18.3] years; 50.5% female; 49.5% male; Indigenous Australian, 2.0%) were included in the model. Estimated annualized infrastructure and staffing costs for the point-of-care troponin pathways, assuming a 5-year device life span, was $2.27 million for the pathway without prehospital discharge and $4.60 million for the pathway with prehospital discharge (incorporating virtual ED costs). In the decision tree model, total annual cost using prehospital point-of-care troponin and paramedic risk stratification was lower compared with existing care both without prehospital discharge (cost savings, $6.45 million; 95% uncertainty interval [UI], $0.59-$16.52 million; lower in 94.1% of iterations) and with prehospital discharge (cost savings, $42.84 million; 95% UI, $19.35-$72.26 million; lower in 100% of iterations).

Conclusions and Relevance

Prehospital point-of-care troponin and paramedic risk stratification for patients with acute chest pain could result in substantial cost savings. These findings should be considered by policy makers in decisions surrounding the potential utility of prehospital chest pain risk stratification and point-of-care troponin models provided that safety is confirmed in prospective studies.

Outpatient Myocardial Perfusion Imaging Scan for a Low-Risk Chest Pain Cohort From the Emergency Department: A Retrospective Analysis

Chest pain accounts for a significant attendances at emergency departments (ED). We examined the utility of early stress myocardial perfusion imaging (SMPI) for stratification of low-risk patients post-ED discharge. A retrospective audit was conducted of patients with chest pain and normal troponin-T (<30Ng/L), who were discharged with outpatient SMPI (median = 3 days post-ED discharge) between January 2018 to January 2020. 880 patients were included and followed up for 12 months. Outcomes measured were: 1) Cardiac events (CE) within 1 year of visit or 2) Significant coronary artery disease (CAD) - coronary angiography demonstrating ≥70% stenosis of epicardial vessels or coronary revascularization procedures performed. In the SMPI negative group, 2 of 802 patients (0.25%) had significant CEs and 11 patients (1.37%) were diagnosed with significant CAD. Of the 78 SMPI positive patients, 1 (1.28%) had a significant CE, while 24 had significant CAD. SMPI had a sensitivity of 65.8%, specificity of 93.7%, positive predictive value of 32.1% and a negative predictive value of 98.4% for predicting adverse CE. Early SMPI post-ED discharge demonstrated high negative predictive value in predicting CEs or significant CAD diagnosis at up to 1 year, suggesting that low-risk patients discharge from ED with early outpatient SMPI is a safe management option.

Rule-out of non-ST-segment elevation acute coronary syndrome by a single, pre-hospital troponin measurement: a randomized trial

AIMS

Patients with suspected non-ST-segment elevation acute coronary syndrome (NSTE-ACS) are routinely transferred to the emergency department (ED). A clinical risk score with point-of-care (POC) troponin measurement might enable ambulance paramedics to identify low-risk patients in whom ED evaluation is unnecessary. The aim was to assess safety and healthcare costs of a pre-hospital rule-out strategy using a POC troponin measurement in low-risk suspected NSTE-ACS patients.

METHODS AND RESULTS

This investigator-initiated, randomized clinical trial was conducted in five ambulance regions in the Netherlands. Suspected NSTE-ACS patients with HEAR (History, ECG, Age, Risk factors) score ≤3 were randomized to pre-hospital rule-out with POC troponin measurement or direct transfer to the ED. The sample size calculation was based on the primary outcome of 30-day healthcare costs. Secondary outcome was safety, defined as 30-day major adverse cardiac events (MACE), consisting of ACS, unplanned revascularization or all-cause death. : A total of 863 participants were randomized. Healthcare costs were significantly lower in the pre-hospital strategy (€1349 ± €2051 vs. €1960 ± €1808) with a mean difference of €611 [95% confidence interval (CI): 353-869; P < 0.001]. In the total population, MACE were comparable between groups [3.9% (17/434) in pre-hospital strategy vs. 3.7% (16/429) in ED strategy; P = 0.89]. In the ruled-out ACS population, MACE were very low [0.5% (2/419) vs. 1.0% (4/417)], with a risk difference of -0.5% (95% CI -1.6%-0.7%; P = 0.41) in favour of the pre-hospital strategy.

CONCLUSION

Pre-hospital rule-out of ACS with a POC troponin measurement in low-risk patients significantly reduces healthcare costs while incidence of MACE was low in both strategies.

TRIAL REGISTRATION

Clinicaltrials.gov identifier NCT05466591 and International Clinical Trials Registry Platform id NTR 7346.

Prehospital risk assessment in patients suspected of non-ST-segment elevation acute coronary syndrome: a systematic review and meta-analysis

OBJECTIVE

To review, inventory and compare available diagnostic tools and investigate which tool has the best performance for prehospital risk assessment in patients suspected of non-ST-segment elevation acute coronary syndrome (NSTE-ACS).

METHODS

Systematic review and meta-analysis. Medline and Embase were searched up till 1 April 2021. Prospective studies with patients, suspected of NSTE-ACS, presenting in the primary care setting or by emergency medical services (EMS) were included. The most important exclusion criteria were studies including only patients with ST-elevation myocardial infarction and studies before 1995, the pretroponin era. The primary end point was the final hospital discharge diagnosis of NSTE-ACS or major adverse cardiac events (MACE) within 6 weeks. Risk of bias was evaluated by the Quality Assessment of Diagnostic Accuracy Studies Criteria.

MAIN OUTCOME AND MEASURES

Sensitivity, specificity and likelihood ratio of findings for risk stratification in patients suspected of NSTE-ACS.

RESULTS

In total, 15 prospective studies were included; these studies reflected in total 26 083 patients. No specific variables related to symptoms, physical examination or risk factors were useful in risk stratification for NSTE-ACS diagnosis. The most useful electrocardiographic finding was ST-segment depression (LR+3.85 (95% CI 2.58 to 5.76)). Point-of-care troponin was found to be a strong predictor for NSTE-ACS in primary care (LR+14.16 (95% CI 4.28 to 46.90) and EMS setting (LR+6.16 (95% CI 5.02 to 7.57)). Combined risk scores were the best for risk assessment in an NSTE-ACS. From the combined risk scores that can be used immediately in a prehospital setting, the PreHEART score, a validated combined risk score for prehospital use, derived from the HEART score (History, ECG, Age, Risk factors, Troponin), was most useful for risk stratification in patients with NSTE-ACS (LR+8.19 (95% CI 5.47 to 12.26)) and for identifying patients without ACS (LR-0.05 (95% CI 0.02 to 0.15)).

DISCUSSION

Important study limitations were verification bias and heterogeneity between studies. In the prehospital setting, several diagnostic tools have been reported which could improve risk stratification, triage and early treatment in patients suspected for NSTE-ACS. On-site assessment of troponin and combined risk scores derived from the HEART score are strong predictors. These results support further studies to investigate the impact of these new tools on logistics and clinical outcome.

FUNDING

This study is funded by ZonMw, the Dutch Organisation for Health Research and Development.

TRIAL REGISTRATION NUMBER

This meta-analysis was published for registration in PROSPERO prior to starting (CRD York, CRD42021254122).

Point-of-care testing with high-sensitivity cardiac troponin assays: the challenges and opportunities

Methods to improve the safety, accuracy and efficiency of assessment of patients with suspected acute coronary symptoms have occupied decades of study and have supported significant changes in clinical practice. Much of the progress is reliant on results of laboratory-based high-sensitivity cardiac troponin assays that can detect low concentrations with high precision. Until recently, point-of-care (POC) platforms were unable to perform with similar analytical precision as laboratory-based assays, and recommendations for their use in accelerated assessment strategies for patients with suspected acute coronary syndrome has been limited. As POC assays can provide troponin results within 20 min, and can be used proximate to patient care, improvements in the efficiency of assessment of patients with suspected acute coronary syndrome is possible, particularly with new high-sensitivity assays.

Development of a prehospital prediction model for risk stratification of patients with chest pain

INTRODUCTION

Chest pain is one of the most common reasons for contacting the emergency medical services (EMS). About 15% of these chest pain patients have a high-risk condition, while many of them have a low-risk condition with no need for acute hospital care. It is challenging to at an early stage distinguish whether patients have a low- or high-risk condition. The objective of this study has been to develop prediction models for optimising the identification of patients with low- respectively high-risk conditions in acute chest pain early in the EMS work flow.

METHODS

This prospective observational cohort study included 2578 EMS missions concerning patients who contacted the EMS in a Swedish region due to chest pain in 2018. All the patients were assessed as having a low-, intermediate- or high-risk condition, i.e. occurrence of a time-sensitive diagnosis at discharge from hospital. Multivariate regression analyses using data on symptoms and symptom onset, clinical findings including ECG, previous medical history and Troponin T were carried out to develop models for identification of patients with low- respectively high-risk conditions. Developed models where then tested hold-out data set for internal validation and assessing their accuracy.

RESULTS

Prediction models for risk-stratification based on variables mutual for both low- and high-risk prediction were developed. The variables included were: age, sex, previous medical history of kidney disease, atrial fibrillation or heart failure, Troponin T, ST-depression on ECG, paleness, pain debut during activity, constant pain, pain in right arm and pressuring pain quality. The high-risk model had an area under the receiving operating characteristic curve of 0.85 and the corresponding figure for the low-risk model was 0.78.

CONCLUSIONS

Models based on readily available information in the EMS setting can identify high- and low-risk conditions with acceptable accuracy. A clinical decision support tool based on developed models may provide valuable clinical guidance and facilitate referral to less resource-intensive venues.

Prehospital triage of patients with acute cardiac complaints: study protocol of HART-c, a multicentre prospective study

INTRODUCTION

Emergency department (ED) overcrowding is a major healthcare problem associated with worse patient outcomes and increased costs. Attempts to reduce ED overcrowding of patients with cardiac complaints have so far focused on in-hospital triage and rapid risk stratification of patients with chest pain at the ED. The Hollands-Midden Acute Regional Triage-Cardiology (HART-c) study aimed to assess the amount of patients left at home in usual ambulance care as compared with the new prehospital triage method. This method combines paramedic assessment and expert cardiologist consultation using live monitoring, hospital data and real-time admission capacity.

METHODS AND ANALYSIS

Patients visited by the emergency medical services (EMS) for cardiac complaints are included. EMS consultation consists of medical history, physical examination and vital signs, and ECG measurements. All data are transferred to a newly developed platform for the triage cardiologist. Prehospital data, in-hospital medical records and real-time admission capacity are evaluated. Then a shared decision is made whether admission is necessary and, if so, which hospital is most appropriate. To evaluate safety, all patients left at home and their general practitioners (GPs) are contacted for 30-day adverse events.

ETHICS AND DISSEMINATION

The study is approved by the LUMC's Medical Ethics Committee. Patients are asked for consent for contacting their GPs. The main results of this trial will be disseminated in one paper.

DISCUSSION

The HART-c study evaluates the efficacy and feasibility of a prehospital triage method that combines prehospital patient assessment and direct consultation of a cardiologist who has access to live-monitored data, hospital data and real-time hospital admission capacity. We expect this triage method to substantially reduce unnecessary ED visits.

Performance of a simplified HEART score and HEART-GP score for evaluating chest pain in urgent primary care

Background

Chest pain is a common symptom in urgent primary care. The distinction between urgent and non-urgent causes can be challenging. A modified version of the HEART score, in which troponin is omitted (‘simplified HEART’) or replaced by the so-called ‘sense of alarm’ (HEART-GP), may aid in risk stratification.

Method

This study involved a retrospective, observational cohort of consecutive patients evaluated for chest pain at a large-scale, out-of-hours, regional primary care facility in the Netherlands, with 6‑week follow-up for major adverse cardiac events (MACEs). The outcome of interest is diagnostic accuracy, including positive predictive value (PPV) and negative predictive value (NPV).

Results

We included 664 patients; MACEs occurred in 4.8% (n = 32). For  simplified HEART and HEART-GP, we found C‑statistics of 0.86 (95% confidence interval (CI) 0.80–0.91) and 0.90 (95% CI 0.85–0.95), respectively. Optimal diagnostic accuracy was found for a simplified HEART score ≥2 (PPV 9%, NPV 99.7%), HEART-GP score ≥3 (PPV 11%, NPV 99.7%) and HEART-GP score ≥4 (PPV 16%, NPV 99.4%). Physicians referred 157 patients (23.6%) and missed 6 MACEs. A simplified HEART score ≥2 would have picked up 5 cases, at the expense of 332 referrals (50.0%, p < 0.001). A HEART-GP score of ≥3 and ≥4 would have detected 5 and 3 MACEs and led to 293 (44.1%, p < 0.001) and 186 (28.0%, p = 0.18) referrals, respectively.

Conclusion

HEART-score modifications including the physicians’ ‘sense of alarm’ may be used as a risk stratification tool for chest pain in primary care in the absence of routine access to troponin assays. Further validation is warranted.

Supplementary Information

The online version of this article (10.1007/s12471-020-01529-4) contains supplementary material, which is available to authorized users.

Prehospital use of a modified HEART Pathway and point-of-care troponin to predict cardiovascular events

The HEART Pathway is a validated risk stratification protocol for Emergency Department patients with chest pain that has yet to be tested in the prehospital setting. This study seeks to test the performance of a prehospital modified HEART Pathway (PMHP). A prospective cohort study of adults with chest pain without ST-segment elevation myocardial infarction was conducted at three EMS agencies between 12/2016-1/2018. To complete a PMHP assessment, paramedics drew blood, measured point-of-care (POC) troponin (i-STAT; Abbott Point of Care) and calculated a HEAR score. Patients were stratified into three groups: high-risk based on an elevated troponin, low-risk based on a HEAR score <4 with a negative troponin, or moderate risk for a HEAR score ≥4 with a negative troponin. Sensitivity, specificity, negative and positive predictive values of the PMHP for detection of major adverse cardiac events (MACE: cardiac death, MI, or coronary revascularization) at 30-days were calculated. A total of 506 patients were accrued, with PMHP completed in 78.1% (395/506). MACE at 30-days occurred in 18.7% (74/395). Among these patients, 7.1% (28/395) were high risk yielding a specificity and PPV for 30-day MACE of 96.6% (95%CI: 94.0–98.3%) and 60.7% (95%CI: 40.6–78.6%) respectively. Low-risk assessments occurred in 31.4% (124/395), which were 90.5% (95%CI: 81.5–96.1%) sensitive for 30-day MACE with a NPV of 94.4% (95%CI: 88.7–97.7%). Moderate-risk assessments occurred in 61.5% (243/395), of which 20.6% had 30-day MACE. The PMHP is able to identify high-risk and low-risk groups with high specificity and negative predictive value for 30-day MACE.

Recent developments in diagnosis and risk stratification of non-ST-elevation acute coronary syndrome

In the past year, a number of important papers have been published on non-ST-elevation acute coronary syndrome, highlighting progress in clinical care. The current review focuses on early diagnosis and risk stratification using biomarkers and advances in intracoronary imaging.

Pre-hospital point-of-care troponin measurement: a clinical example of its additional value

In the majority of patients with chest pain, an acute coronary syndrome (ACS) can be ruled out. However, early recognition of an ACS is required in order to start treatment as soon as possible and reduce risks associated with myocardial ischaemia. Because of the lack of pre-hospital protocols to rule out an ACS, patients with a suspected ACS are transported to the emergency department, where the HEART score can be used to estimate the risk of major adverse cardiac events (MACE). Patients with a low HEART score have a low risk of MACE. A point-of-care (POC) troponin measurement enables ambulance paramedics to calculate the HEART score in the pre-hospital setting. POC troponin measurement and HEART score assessment have several potential advantages, including early recognition of an ACS and identification of high-risk patients before hospital arrival. Moreover, pre-hospital rule-out of an ACS could prevent unnecessary emergency department visits. The safety and cost-effectiveness of referring low-risk patients with a normal POC troponin value to the general practitioner are currently being investigated in the ARTICA randomised trial. This point-of-view article demonstrates one of the potential advantages of early detection of an ACS.