Cardiac Outcomes Through Digital Evaluation (CODE) STEMI Project: Prehospital Digitally-Assisted Reperfusion Strategies

Informing Utstein-style reporting guidelines for prehospital thrombolysis: A scoping review

BACKGROUND

Rural Australians with acute myocardial infarction (AMI) face higher mortality rates due to limited access to specialised cardiac services. Paramedic-administered prehospital thrombolysis (PHT) has emerged as an alternative to primary percutaneous intervention (pPCI) for patients facing barriers or delays to cardiac care. There is variability in PHT practices among Australian ambulance services, lacking standardised definitions and outcome measures. The aim of this scoping review was to identify quality indicators and influencing factors associated with outcomes for patients receiving PHT.

METHODS

A systematic search of literature in SCOPUS and Academic Search Complete, CINAHL and Health Source: Nursing/Academic Edition databases via EBSCO (Health) was conducted following the Joanna Briggs Institute methodology. Peer-reviewed studies from the past decade were screened using search criteria relevant to prehospital thrombolysis and quality indicators. Data extraction was performed and themed using five domains from the Utstein-style template commonly known for standardised prehospital cardiac arrest reporting.

RESULTS

After removing duplicates, the search yielded 3596 articles with 28 empirical studies meeting inclusion criteria for the review. These were primarily retrospective cohort studies performed in Australia, Canada and the United States. The scoping review identified 24 clinical quality indicators and factors related to Emergency Medical Service (EMS) systems, AMI recognition and ambulance dispatch, patient variables, PHT processes and patient outcomes. These findings correlate to the Donabedian structure-process-outcome quality of care model and have utility to inform future PHT reporting guidelines for jurisdictional ambulance services.

CONCLUSIONS

Given the variability in prehospital practice across Australian ambulance services, standardised reporting on quality indicators for PHT is needed. The Utstein-style template used to report data on pre-hospital cardiac arrest, trauma and airway management could be used for quality improvement in PHT. This review presents 24 quality indicators representing system, recognition and response, patient, process, and outcomes related to PHT. These results could be used to inform a future Delphi study and Utstein-like reporting guideline for prehospital thrombolysis.

Temporal Trends in Reperfusion Delivery and Clinical Outcomes Following Implementation of a Regional STEMI Protocol – a 12 Year Perspective

Background

The Vancouver Coastal Health (VCH) ST-elevation myocardial infarction (STEMI) program aimed to increase access to primary percutaneous coronary intervention (PPCI) and reduce first-medical-contact-to-device times (FMC-DTs). We evaluated the long-term program impact on PPCI access and FMC-DT, and overall and reperfusion-specific in-hospital mortality.

Methods

We analyzed all VCH STEMI patients between June 2007 and November 2019. The primary outcome was the proportion of patients receiving PPCI over 4 program implementation phases over 12 years. We also evaluated overall changes in median FMC-DT and the proportion of patients achieving guideline-mandated FMC-DT, in addition to overall and reperfusion-specific in-hospital mortality.

Results

A total of 3138 of 4305 VCH STEMI patients were treated with PPCI. PPCI rates increased from 40.2% to 78.7% from 2007 to 2019 (P < 0.001). From phase 1 to 4, median FMC-DT improved from 118 to 93 minutes (percutaneous coronary intervention [PCI]-capable hospitals, P < 0.001) and from 174 to 118 minutes (non-PCI-capable hospitals, P < 0.001), with a concomitant increase in those achieving guideline-mandated FMC-DT (35.5% to 66.1%, P < 0.001). Overall in-hospital mortality was 9.0% (P = 0.20 across phases), with mortality differing significantly by reperfusion strategy (4.0% fibrinolysis, 5.7% PPCI, 30.6% no reperfusion therapy, P < 0.001). Mortality significantly decreased from phase 1 to phase 4 at non-PCI-capable centres (9.6% to 3.9%, P = 0.022) but not at PCI-capable centres (8.7% vs 9.9%, P = 0.27).

Conclusions

A regional STEMI program increased the proportion of patients who received PPCI and improved reperfusion times over 12 years. Although no statistically significant decrease occurred in overall regional mortality incidence, mortality incidence was decreased for patients presenting to non-PCI-capable centres.

Utility of prehospital electrocardiogram interpretation in ST-segment elevation myocardial infarction utilizing computer interpretation and transmission for interventional cardiologist consultation

Objectives

We examined the appropriateness of prehospital cardiac catheter laboratory activation (CCL‐A) in ST‐segment elevation myocardial infarction (STEMI) utilizing the University of Glasgow algorithm (UGA) and remote interventional cardiologist consultation.

Background

The incremental benefit of prehospital electrocardiogram (PH‐ECG) transmission on the diagnostic accuracy and appropriateness of CCL‐A has been examined in a small number of studies with conflicting results.

Methods

We identified consecutive PH‐ECG transmissions between June 2, 2010 and October 6, 2016. Blinded adjudication of ECGs, appropriateness of CCL‐A, and index diagnoses were performed using the fourth universal definition of MI. The primary outcome was the appropriate CCL‐A rate. Secondary outcomes included rates of false‐positive CCL‐A, inappropriate CCL‐A, and inappropriate CCL nonactivation.

Results

Among 1088 PH‐ECG transmissions, there were 565 (52%) CCL‐As and 523 (48%) CCL nonactivations. The appropriate CCL‐A rate was 97% (550 of 565 CCL‐As), of which 4.9% (n = 27) were false‐positive. The inappropriate CCL‐A rate was 2.7% (15 of 565 CCL‐As) and the inappropriate CCL nonactivation rate was 3.6% (19 of 523 CCL nonactivations). Reasons for appropriate CCL nonactivation (n = 504) included nondiagnostic ST‐segment elevation (n = 128, 25%), bundle branch block (n = 132, 26%), repolarization abnormality (n = 61, 12%), artefact (n = 72, 14%), no ischemic symptoms (n = 32, 6.3%), severe comorbidities (n = 26, 5.2%), transient ST‐segment elevation (n = 20, 4.0%), and others.

Conclusions

PH‐ECG interpretation utilizing UGA with interventional cardiologist consultation accurately identified STEMI with low rates of inappropriate and false‐positive CCL‐As, whereas using UGA alone would have almost doubled CCL‐As. The benefits of cardiologist consultation were identifying “masquerading” STEMI and avoiding unnecessary CCL‐As.

Late Outcomes of Patients With Prehospital ST-Segment Elevation and Appropriate Cardiac Catheterization Laboratory Nonactivation

Background Patients with suspected ST-segment-elevation myocardial infarction (STEMI) and cardiac catheterization laboratory nonactivation (CCL-NA) or cancellation have reportedly similar crude and higher adjusted risks of death compared with those with CCL activation, though reasons for these poor outcomes are not clear. We determined late clinical outcomes among patients with prehospital ECG STEMI criteria who had CCL-NA compared with those who had CCL activation. Methods and Results We identified consecutive prehospital ECG transmissions between June 2, 2010 to October 6, 2016. Diagnoses according to the Fourth Universal Definition of myocardial infarction (MI), particularly rates of myocardial injury, were adjudicated. The primary outcome was all-cause death. Secondary outcomes included cardiovascular death/MI/stroke and noncardiovascular death. To explore competing risks, cause-specific hazard ratios (HRs) were obtained. Among 1033 included ECG transmissions, there were 569 (55%) CCL activations and 464 (45%) CCL-NAs (1.8% were inappropriate CCL-NAs). In the CCL activation group, adjudicated index diagnoses included MI (n=534, 94%, of which 99.6% were STEMI and 0.4% non-STEMI), acute myocardial injury (n=15, 2.6%), and chronic myocardial injury (n=6, 1.1%). In the CCL-NA group, diagnoses included MI (n=173, 37%, of which 61% were non-STEMI and 39% STEMI), chronic myocardial injury (n=107, 23%), and acute myocardial injury (n=47, 10%). At 2 years, the risk of all-cause death was higher in patients who had CCL-NA compared with CCL activation (23% versus 7.9%, adjusted risk ratio, 1.58, 95% CI, 1.24-2.00), primarily because of an excess in noncardiovascular deaths (adjusted HR, 3.56, 95% CI, 2.07-6.13). There was no significant difference in the adjusted risk for cardiovascular death/MI/stroke between the 2 groups (HR, 1.23, 95% CI, 0.87-1.73). Conclusions CCL-NA was not primarily attributable to missed STEMI, but attributable to "masquerading" with high rates of non-STEMI and myocardial injury. These patients had worse late outcomes than patients who had CCL activation, mainly because of higher rates of noncardiovascular deaths.

Sex and Gender Equity in Prehospital Electrocardiogram Acquisition

INTRODUCTION

Research in cardiac care has identified significant gender-based differences across many outcomes. Women with heart disease are less likely both to be diagnosed and to receive standard care. Gender-based disparities in the prehospital setting are under-researched, but they were found to exist within rates of 12-lead electrocardiogram (ECG) acquisition within one urban Emergency Medical Services (EMS) agency.

STUDY OBJECTIVE

This study evaluates the quality improvement (QI) initiative that was implemented in that agency to raise overall rates of 12-lead ECG acquisition and reduce the gap in acquisition rates between men and women.

METHODS

This QI project included two interventions: revised indications for 12-lead acquisition, and training that highlighted sex- and gender-based differences relevant to patient care. To evaluate this project, a retrospective database review identified all patient contacts that potentially involved cardiac assessment over 18 months. The primary outcome was the rate of 12-lead acquisition among patients with qualifying complaints. This was assessed by mean rates of acquisition in before and after periods, as well as segmented regression in an interrupted time series. Secondary outcomes included differences in rates of 12-lead acquisition, both overall and in individual complaint categories, each compared between men/women and before/after the interventions.

RESULTS

Among patients with qualifying complaints, the mean rate of 12-lead acquisition in the lead-in period was 22.5% (95% CI, 21.8% - 23.2%) with no discernible trend. The protocol change and training were each associated with a significant absolute level increase in the acquisition rate: 2.09% (95% CI, 0.21% - 4.0%; P = .03) and 3.2% (95% CI, 1.18% - 5.22%; P = .003), respectively. When compared by gender and time period, women received fewer 12-leads than men overall, and more 12-leads were acquired after the interventions than before. There were also significant interactions between gender and period, both overall (2.8%; 95% CI, 1.9% - 3.6%; P < .0001) and in all complaint categories except falls and heart problems.

CONCLUSION

This QI project resulted in an increase in 12-leads acquired. Pre-existing gaps in rates of acquisition between men and women were reduced but did not disappear. On-going research is examining the reasons behind these differences from the perspective of prehospital providers.

Effect of Real-Time Physician Oversight of Prehospital STEMI Diagnosis on ECG-Inappropriate and False Positive Catheterization Laboratory Activation

Background

ST-elevation myocardial infarction diagnosis at first medical contact (FMC) and prehospital cardiac catheterization laboratory (CCL) activation are associated with reduced total ischemic time and therefore have become the dominant ST-elevation myocardial infarction referral method in primary percutaneous coronary intervention systems. We sought to determine whether physician oversight was associated with improved diagnostic performance in a prehospital CCL activation system and what effect the additional interpretation has on treatment delay.

Methods

Between 2012 and 2015, all patients in 2 greater Montreal catchment areas with a chief symptom of chest paint or dyspnea had an in-the-field electrocardiogram (ECG). A machine diagnosis of "acute myocardial infarction" resulted either in automatic CCL (automated cohort without oversight) or transmission of the ECG to the receiving centre emergency physician for reinterpretation before CCL activation. System performance was assessed in terms of the proportion of false positive and inappropriate activations (IA), as well as the proportion of patients with FMC-to-device times ≤ 90 minutes.

Results

Four hundred twenty-eight (428) activations were analyzed (311 automated; 117 with physician oversight). Physician oversight tended to decrease IAs (7% vs 3%; P = 0.062), but was also associated with a smaller proportion of patients achieving target FMC-to-device (76% vs 60%; P < 0.001). There was no significant effect on the proportion of false positive activation.

Conclusions

Real-time physician oversight might be associated with fewer IAs, but also appears to have a deleterious effect on FMC-to-device performance. Identifying predictors of IA could improve overall performance by selecting ECGs that merit physician oversight and streamlining others. Larger clinical studies are warranted.

Reducing Delay to Treatment of ST-Elevation Myocardial Infarction With Software Electrocardiographic Interpretation and Transmission (SCINET)

Background

Prehospital diagnosis of ST-elevation myocardial infarction (STEMI) has resulted in improved outcomes. However, many patients still walk in to the emergency department (ED) with STEMI, experiencing delays and worse outcomes. Software electrocardiogram (ECG) diagnosis of STEMI and electronic transmission to a cardiologist may result in improved door-to-device (D2D) times.

Methods

We retrospectively identified all patients presenting with STEMI from January 2015 to September 2016. Components of delay in D2D, ED variables, and the patients’ ECGs were extracted from our regional database. All ECGs performed for suspected myocardial infarction in the region were extracted over the study period. We assessed the accuracy of the software 12SL in diagnosing STEMI, ED contributors to delays in D2D, and the potential reduction in D2D if software diagnosis of STEMI resulted in activation of the cardiac catheterization laboratory.

Results

A total of 379 patients presented to an ED in our region and received primary percutaneous coronary intervention over the study period. In the 143,574 ECGs performed over the study period for suspected STEMI, the overall sensitivity and specificity of 12SL were 90.5% and 99.98%, respectively. We estimated a potential 17-minute reduction in D2D in the 90.5% of patients correctly identified as having STEMI, with a false activation rate of 4%. Female patients and older patients experienced an even larger potential benefit, with 24- and 25-minute reductions in D2D, respectively.

Conclusions

Patients who walk in to an ED with STEMI experience significant system-related delays in recognition and treatment. Automated software diagnosis of STEMI is accurate and could result in significant improvements in D2D times.

2019 Canadian Cardiovascular Society/Canadian Association of Interventional Cardiology Guidelines on the Acute Management of ST-Elevation Myocardial Infarction: Focused Update on Regionalization and Reperfusion

Rapid reperfusion of the infarct-related artery is the cornerstone of therapy for the management of acute ST-elevation myocardial infarction (STEMI). Canada's geography presents unique challenges for timely delivery of reperfusion therapy for STEMI patients. The Canadian Cardiovascular Society/Canadian Association of Interventional Cardiology STEMI guideline was developed to provide advice regarding the optimal acute management of STEMI patients irrespective of where they are initially identified: in the field, at a non-percutaneous coronary intervention-capable centre or at a percutaneous coronary intervention-capable centre. We had also planned to evaluate and incorporate sex and gender considerations in the development of our recommendations. Unfortunately, inadequate enrollment of women in randomized trials, lack of publication of main outcomes stratified according to sex, and lack of inclusion of gender as a study variable in the available literature limited the feasibility of such an approach. The Grading Recommendations, Assessment, Development, and Evaluation system was used to develop specific evidence-based recommendations for the early identification of STEMI patients, practical aspects of patient transport, regional reperfusion decision-making, adjunctive prehospital interventions (oxygen, opioids, antiplatelet therapy), and procedural aspects of mechanical reperfusion (access site, thrombectomy, antithrombotic therapy, extent of revascularization). Emphasis is placed on integrating these recommendations as part of an organized regional network of STEMI care and the development of appropriate reperfusion and transportation pathways for any given region. It is anticipated that these guidelines will serve as a practical template to develop systems of care capable of providing optimal treatment for a wide range of STEMI patients.

A systematic review of prehospital telehealth utilization

Objective There has been moderate evidence of telehealth utilization in the field of emergency medicine, but less is known about telehealth in prehospital emergency medical services (EMS). The objective of this study is to explore the extent, focus, and utilization of telehealth for prehospital emergency care through the analysis of published research. Methods The authors conducted a systematic literature review by extracting data from multiple research databases (including MEDLINE/PubMed, CINAHL Complete, and Google Scholar) published since 2000. We used consistent key search terms to identify clinical interventions and feasibility studies involving telehealth and EMS, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results We identified 68 articles focused specifically on telehealth interventions in prehospital care. The majority (54%) of the studies involved stroke and acute cardiovascular care, while only 7% of these (4) focused on telehealth for primary care. The two most common delivery methods were real-time video-conferencing capabilities (38%) and store and forward (25%); and this variation was based upon the clinical focus. There has been a significant and positive trend towards greater telehealth utilization. European telehealth programs were most common (51% of the studies), while 38% were from the United States. Discussion and Conclusions Despite positive trends, telehealth utilization in prehospital emergency care is fairly limited given the sheer number of EMS agencies worldwide. The results of this study suggest there are significant opportunities for wider diffusion in prehospital care. Future work should examine barriers and incentives for telehealth adoption in EMS.

Sustained Performance of a "Physicianless" System of Automated Prehospital STEMI Diagnosis and Catheterization Laboratory Activation

BACKGROUND

Treatment times for primary percutaneous coronary intervention frequently exceed the recommended maximum delay. Automated "physicianless" systems of prehospital cardiac catheterization laboratory (CCL) activation show promise, but have been met with resistance over concerns regarding the potential for false positive and inappropriate activations (IAs).

METHODS

From 2010 to 2015, first responders performed electrocardiograms (ECGs) in the field for all patients with a complaint of chest pain or dyspnea. An automated machine diagnosis of "acute myocardial infarction" resulted in immediate CCL activation and direct transfer without transmission or human reinterpretation of the ECG prior to patient arrival. Any activation resulting from a nondiagnostic ECG (no ST-elevation) was deemed an IA, whereas activations resulting from ECG's compatible with ST-elevation myocardial infarction but without angiographic evidence of a coronary event were deemed false positive. In 2012, the referral algorithm was modified to exclude supraventricular tachycardia and left bundle branch block.

RESULTS

There were 155 activations in the early cohort (2010-2012; prior to algorithm modification) and 313 in the late cohort (2012-2015). Algorithm modification resulted in a 42% relative decrease in the rate of IAs (12% vs 7%; P < 0.01) without a significant effect on treatment delay.

CONCLUSIONS

A combination of prehospital automated ST-elevation myocardial infarction diagnosis and "physicianless" CCL activation is safe and effective in improving treatment delay and these results are sustainable over time. The performance of the referral algorithm in terms of IA and false positive is at least on par with systems that ensure real-time human oversight.

The Interdisciplinary Management of Acute Chest Pain

BACKGROUND

Acute chest pain of non-traumatic origin is a common reason for presentation to physician's offices and emergency rooms. Coronary heart disease is the cause in up to 25% of cases. Because acute chest pain, depending on its etiology, may be associated with a high risk of death, rapid, goal-oriented management is mandatory.

METHODS

This review is based on pertinent articles and guidelines retrieved by a selective search in PubMed.

RESULTS

History-taking, physical examination, and a 12-lead electrocardiogram (ECG) are the first steps in the differential diagnostic process and generally allow the identification of features signifying a high risk of lifethreatening illness. If the ECG reveals ST-segment elevation, cardiac catheterization is indicated. The timedependent measurement of highly sensitive troponin values is a reliable test for the diagnosis or exclusion of acute myocardial infarction. A wide variety of other potential causes (e.g., vascular, musculoskeletal, gastroenterologic, or psychosomatic) must be identified from the history if they are to be treated appropriately. Elderly patients need special attention.

CONCLUSION

Acute chest pain is a major diagnostic challenge for the physician. Common errors are traceable to non-recognition of important causes and to an inadequate diagnostic work-up. Future studies should be designed to help optimize the interdisciplinary management of patients with chest pain.

Feasibility of AmbulanCe-Based Telemedicine (FACT) study: safety, feasibility and reliability of third generation in-ambulance telemedicine

Background

Telemedicine is currently mainly applied as an in-hospital service, but this technology also holds potential to improve emergency care in the prehospital arena. We report on the safety, feasibility and reliability of in-ambulance teleconsultation using a telemedicine system of the third generation.

Methods

A routine ambulance was equipped with a system for real-time bidirectional audio-video communication, automated transmission of vital parameters, glycemia and electronic patient identification. All patients ( ≥18 years) transported during emergency missions by a Prehospital Intervention Team of the Universitair Ziekenhuis Brussel were eligible for inclusion. To guarantee mobility and to facilitate 24/7 availability, the teleconsultants used lightweight laptop computers to access a dedicated telemedicine platform, which also provided functionalities for neurological assessment, electronic reporting and prehospital notification of the in-hospital team. Key registrations included any safety issue, mobile connectivity, communication of patient information, audiovisual quality, user-friendliness and accuracy of the prehospital diagnosis.

Results

Prehospital teleconsultation was obtained in 41 out of 43 cases (95.3%). The success rates for communication of blood pressure, heart rate, blood oxygen saturation, glycemia, and electronic patient identification were 78.7%, 84.8%, 80.6%, 64.0%, and 84.2%. A preliminary prehospital diagnosis was formulated in 90.2%, with satisfactory agreement with final in-hospital diagnoses. Communication of a prehospital report to the in-hospital team was successful in 94.7% and prenotification of the in-hospital team via SMS in 90.2%. Failures resulted mainly from limited mobile connectivity and to a lesser extent from software, hardware or human error. The user acceptance was high.

Conclusions

Ambulance-based telemedicine of the third generation is safe, feasible and reliable but further research and development, especially with regard to high speed broadband access, is needed before this approach can be implemented in daily practice.

Performance of a new "physician-less" automated system of prehospital ST-segment elevation myocardial infarction diagnosis and catheterization laboratory activation

The door-to-balloon times frequently exceed the recommended delay. We therefore evaluated the performance of a novel "physician-less" cardiac catheterization laboratory (CCL) activation system relying on the automated electrocardiographic diagnosis alone. From January 2010 to 2012, first responders performed electrocardiograms in the field for all patients with a complaint of chest pain or dyspnea. An automated machine diagnosis of "acute myocardial infarction" resulted in immediate CCL activation and direct transfer without human reinterpretation or transmission of the electrocardiogram. Any activation resulting from a nondiagnostic ECG (no ST-segment elevation) was deemed inappropriate and classified as resulting from either human or machine error. Of 155 activations, 136 (88%) were electrocardiographically appropriate. Of these, 128 patients had a final diagnosis of ST-segment elevation myocardial infarction. A door-to-balloon time of <90 minutes was achieved in 99%, the procedural success was high (94%), and the overall mortality was low (3%). Of the electrocardiographically appropriate activations, 8 (5%) were false-positive results. The remaining 19 activations (12%) were inappropriate. Compared with the electrocardiographically appropriate activations, those with inappropriate activations had significantly greater rates of hypertension (p = 0.0070) and known coronary artery disease (p = 0.0008) and higher presenting heart rates (p <0.0001). The causes for inappropriate activation were approximately evenly split between human and machine error. In conclusion, a combination of prehospital automated ST-segment elevation myocardial infarction diagnosis and "physician-less" CCL activation was safe and effective in ensuring target door-to-balloon times in virtually all patients and resulted in an acceptable rate of inappropriate CCL activation.

To transmit or not to transmit: how good are emergency medical personnel in detecting STEMI in patients with chest pain?

BACKGROUND

There is growing use of prehospital electrocardiograms (ECGs) in establishing early diagnosis of ST segment myocardial infarction (STEMI) to facilitate early reperfusion. This study aimed to determine the predictive value of prehospital ECGs interpreted by nonphysician emergency medical services (EMS) in chest pain presentations.

METHODS

In our city of 658,700 people, EMS/paramedics received 21 hours of instruction on STEMI management, ECG acquisition, and interpretation. Suspected STEMI ECGs were wirelessly transmitted to and discussed with a physician for possible therapy. ECGs deemed negative for STEMI by EMS were not transmitted; patients were transported to the closest hospital without prehospital physician involvement.

RESULTS

From July 21, 2008 to July 21, 2010, there were 5426 chest pain calls to EMS, 380 were suspected STEMI cases. The remaining ECGs were deemed negative for STEMI by EMS. To audit the nontransmitted ECGs we analyzed 323 consecutive patients over 2 selected months (January and June 2010) for comparison. Of nontransmitted cases there was 1 missed and 2 STEMIs that developed subsequently. Based on 380 transmitted and 323 nontransmitted cases, the sensitivity and specificity of EMS detecting STEMI were 99.6% and 67.6%, respectively. The positive and negative predictive values for STEMI were 59.5% and 99.7%, respectively.

CONCLUSIONS

Our findings demonstrate nonphysician EMS interpretation of STEMI on prehospital ECG has excellent sensitivity and high negative predictive value. This finding supports the use of prehospital ECGs interpreted by EMS to help identify and facilitate treatment of STEMI. These results may have broad implications on staffing models for first responder/EMS units.