Minimizing false activation of cath lab for STEMI — A realistic goal?

Missing occlusions: Quality gaps for ED patients with occlusion MI

BACKGROUND

ST-elevation Myocardial Infarction (STEMI) guidelines encourage monitoring of false positives (Code STEMI without culprit) but ignore false negatives (non-STEMI with occlusion myocardial infarction [OMI]). We evaluated the hospital course of emergency department (ED) patients with acute coronary syndrome (ACS) using STEMI vs OMI paradigms.

METHODS

This retrospective chart review examined all ACS patients admitted through two academic EDs, from June 2021 to May 2022, categorized as 1) OMI (acute culprit lesion with TIMI 0-2 flow, or acute culprit lesion with TIMI 3 flow and peak troponin I >10,000 ng/L; or, if no angiogram, peak troponin >10,000 ng/L with new regional wall motion abnormality), 2) NOMI (Non-OMI, i.e. MI without OMI) or 3) MIRO (MI ruled out: no troponin elevation). Patients were stratified by admission for STEMI. Initial ECGs were reviewed for automated interpretation of "STEMI", and admission/discharge diagnoses were compared.

RESULTS

Among 382 patients, there were 141 OMIs, 181 NOMIs, and 60 MIROs. Only 40.4% of OMIs were admitted as STEMI: 60.0% had "STEMI" on ECG, and median door-to-cath time was 103 min (IQR 71-149). But 59.6% of OMIs were not admitted as STEMI: 1.3% had "STEMI" on ECG (p < 0.001) and median door-to-cath time was 1712 min (IQR 1043-3960; p < 0.001). While 13.9% of STEMIs were false positive and had a different discharge diagnosis, 32.0% of Non-STEMIs had OMI but were still discharged as "Non-STEMI."

CONCLUSIONS

STEMI criteria miss a majority of OMI, and discharge diagnoses highlight false positive STEMI but never false negative STEMI. The OMI paradigm reveals quality gaps and opportunities for improvement.

A Retrospective Clinical Evaluation of an Artificial Intelligence Screening Method for Early Detection of STEMI in the Emergency Department

BACKGROUND

Rapid revascularization is the key to better patient outcomes in ST-elevation myocardial infarction (STEMI). Direct activation of cardiac catheterization laboratory (CCL) using artificial intelligence (AI) interpretation of initial electrocardiography (ECG) might help reduce door-to-balloon (D2B) time. To prove that this approach is feasible and beneficial, we assessed the non-inferiority of such a process over conventional evaluation and estimated its clinical benefits, including a reduction in D2B time, medical cost, and 1-year mortality.

METHODS

This is a single-center retrospective study of emergency department (ED) patients suspected of having STEMI from January 2021 to June 2021. Quantitative ECG (QCG™), a comprehensive cardiovascular evaluation system, was used for screening. The non-inferiority of the AI-driven CCL activation over joint clinical evaluation by emergency physicians and cardiologists was tested using a 5% non-inferiority margin.

RESULTS

Eighty patients (STEMI, 54 patients [67.5%]) were analyzed. The area under the curve of QCG score was 0.947. Binned at 50 (binary QCG), the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 98.1% (95% confidence interval [CI], 94.6%, 100.0%), 76.9% (95% CI, 60.7%, 93.1%), 89.8% (95% CI, 82.1%, 97.5%) and 95.2% (95% CI, 86.1%, 100.0%), respectively. The difference in sensitivity and specificity between binary QCG and the joint clinical decision was 3.7% (95% CI, -3.5%, 10.9%) and 19.2% (95% CI, -4.7%, 43.1%), respectively, confirming the non-inferiority. The estimated median reduction in D2B time, evaluation cost, and the relative risk of 1-year mortality were 11.0 minutes (interquartile range [IQR], 7.3-20.0 minutes), 26,902.2 KRW (22.78 USD) per STEMI patient, and 12.39% (IQR, 7.51-22.54%), respectively.

CONCLUSION

AI-assisted CCL activation using initial ECG is feasible. If such a policy is implemented, it would be reasonable to expect some reduction in D2B time, medical cost, and 1-year mortality.

An Artificial Intelligence-Based Alarm Strategy Facilitates Management of Acute Myocardial Infarction

(1) Background: While an artificial intelligence (AI)-based, cardiologist-level, deep-learning model for detecting acute myocardial infarction (AMI), based on a 12-lead electrocardiogram (ECG), has been established to have extraordinary capabilities, its real-world performance and clinical applications are currently unknown. (2) Methods and Results: To set up an artificial intelligence-based alarm strategy (AI-S) for detecting AMI, we assembled a strategy development cohort including 25,002 visits from August 2019 to April 2020 and a prospective validation cohort including 14,296 visits from May to August 2020 at an emergency department. The components of AI-S consisted of chest pain symptoms, a 12-lead ECG, and high-sensitivity troponin I. The primary endpoint was to assess the performance of AI-S in the prospective validation cohort by evaluating F-measure, precision, and recall. The secondary endpoint was to evaluate the impact on door-to-balloon (DtoB) time before and after AI-S implementation in STEMI patients treated with primary percutaneous coronary intervention (PPCI). Patients with STEMI were alerted precisely by AI-S (F-measure = 0.932, precision of 93.2%, recall of 93.2%). Strikingly, in comparison with pre-AI-S (N = 57) and post-AI-S (N = 32) implantation in STEMI protocol, the median ECG-to-cardiac catheterization laboratory activation (EtoCCLA) time was significantly reduced from 6.0 (IQR, 5.0–8.0 min) to 4.0 min (IQR, 3.0–5.0 min) (p < 0.01). The median DtoB time was shortened from 69 (IQR, 61.0–82.0 min) to 61 min (IQR, 56.8–73.2 min) (p = 0.037). (3) Conclusions: AI-S offers front-line physicians a timely and reliable diagnostic decision-support system, thereby significantly reducing EtoCCLA and DtoB time, and facilitating the PPCI process. Nevertheless, large-scale, multi-institute, prospective, or randomized control studies are necessary to further confirm its real-world performance.

Diagnostic performance of a new ECG algorithm for reducing false positive cases in patients suspected acute coronary syndrome

BACKGROUND

Early and correct diagnosis of ST-segment elevation myocardial infarction (STEMI) is crucial for providing timely reperfusion therapy. Patients with ischemic symptoms presenting with ST-segment elevation on the electrocardiogram (ECG) are preferably transported directly to a catheterization laboratory (Cath-lab) for primary percutaneous coronary intervention (PPCI). However, the ECG often contains confounding factors making the STEMI diagnosis challenging leading to false positive Cath-lab activation. The objective of this study was to test the performance of a standard automated algorithm against an additional high specificity setting developed for reducing the false positive STEMI calls.

METHODS

We included consecutive patients with an available digital prehospital ECG triaged directly to Cath-lab for acute coronary angiography between 2009 and 2012. An adjudicated discharge diagnosis of STEMI or no myocardial infarction (no-MI) was assigned for each patient. The new automatic algorithm contains a feature to reduce false positive STEMI interpretation. The STEMI performance with the standard setting (STD) and the high specificity setting (HiSpec) was tested against the adjudicated discharge diagnosis in a retrospective manner.

RESULTS

In total, 2256 patients with an available digital prehospital ECG (mean age 63 ± 13 years, male gender 71%) were included in the analysis. The discharge diagnosis of STEMI was assigned in 1885 (84%) patients. The STD identified 165 true negative and 1457 true positive (206 false positive and 428 false negative) cases (77.3%, 44.5%, 87.6% and 17.3% for sensitivity, specificity, PPV and NPV, respectively). The HiSpec identified 191 true negative and 1316 true positive (180 false positive and 569 false negative) cases (69.8%, 51.5%, 88.0% and 25.1% for sensitivity, specificity, PPV and NPV, respectively). From STD to HiSpec, false positive cases were reduced by 26 (12,6%), but false negative results were increased by 33%.

CONCLUSIONS

Implementing an automated ECG algorithm with a high specificity setting was able to reduce the number of false positive STEMI cases. However, the predictive values for both positive and negative STEMI identification were moderate in this highly selected STEMI population. Finally, due the reduced sensitivity/increased false negatives, a negative AMI statement should not be solely based on the automated ECG statement.

Direct angiographic intervention for acute ischemic stroke with large vessel occlusion

Background:Rapid and effective revascularization is the cornerstone of acute ischemic stroke treatment. Endovascular thrombectomy reperfusion has dramatically changed patients' outcomes with large vessel occlusions. Results of randomized controlled trials have shown that the benefit of this treatment is highly time-sensitive. The purpose of this review is to introduce a new approach to acute stroke treatment - direct angiographic intervention for selected patients. Methods & Results:We examined the issues related to the current guideline-based practice, emphasizing whether the benefit of using advanced multimodal imaging is worth the potential resultant disability generated by delayed reperfusion times. The published evidence supporting this novel concept was reviewed, its safety and feasibility discussed, and appropriate predictive tools for patient selection explored.Conclusion:This new approach may provide benefits for appropriately selected patients. Further prospective trials are needed to clarify the risk-versus-benefit of this approach.Abbreviations and Acronyms: AHA: American Heart AssociationAIS: acute ischemic strokeASA: American Stroke AssociationASPECTS: Alberta Stroke Program Early Computed Tomography ScoreCT: computed tomographyCTA: computed tomography angiographyCTP: computed tomography perfusionDMVO: distal, medium vessel occlusionDSA: digital subtraction angiographyED: Emergency DepartmentEVT: endovascular thrombectomyFD: flat detectorIA: intra-arterialIV: intravenousICH: intracerebral hemorrhageMR: magnetic resonanceMRA: magnetic resonance angiographyMSU: mobile stroke unitNIHSS: National Institutes of Health Stroke ScaleNCCT: non-contrast computed tomographyPLVO: proximal, large vessel occlusionPPV: positive predictive valuePWI: magnetic resonance perfusion-weighted imaging.

Sharing and Teaching Electrocardiograms to Minimize Infarction (STEMI): reducing diagnostic time for acute coronary occlusion in the emergency department

BACKGROUND

Limits to ST-Elevation Myocardial Infarction (STEMI) criteria may lead to prolonged diagnostic time for acute coronary occlusion. We aimed to reduce ECG-to-Activation (ETA) time through audit and feedback on STEMI-equivalents and subtle occlusions, without increasing Code STEMIs without culprit lesions.

METHODS

This multi-centre, quality improvement initiative reviewed all Code STEMI patients from the emergency department (ED) over a one-year baseline and one-year intervention period. We measured ETA time, from the first ED ECG to the time a Code STEMI was activated. Our intervention strategy involved a grand rounds presentation and an internal website presenting weekly local challenging cases, along with literature on STEMI-equivalents and subtle occlusions. Our outcome measure was ETA time for culprit lesions, our process measure was website views/visits, and our balancing measure was the percentage of Code STEMIs without culprit lesions.

RESULTS

There were 51 culprit lesions in the baseline period, and 64 in the intervention period. Median ETA declined from 28.0 min (95% confidence interval [CI] 15.0-45.0) to 8.0 min (95%CI 6.0-15.0). The website garnered 70.4 views/week and 27.7 visitors/week in a group of 80 physicians. There was no change in percentage of Code STEMIs without culprit lesions: 28.2% (95%CI 17.8-38.6) to 20.0% (95%CI 11.2-28.8%). Conclusions Our novel weekly web-based feedback to all emergency physicians was associated with a reduction in ETA time by 20 min, without increasing Code STEMIs without culprit lesions. Local ECG audit and feedback, guided by ETA as a quality metric for acute coronary occlusion, could be replicated in other settings to improve care.

False activation of the cardiac catheterization laboratory: The price to pay for shorter treatment delay

Introduction

In patients with acute ST elevation myocardial ischemia (STEMI), national efforts have focused on reducing door-to-balloon (D2B) times for primary percutaneous coronary intervention (PCI). This emphasis on time-to-treatment may increase the rate of inappropriate cardiac catheterization laboratory (CCL) activations and unnecessary healthcare utilization. To achieve lower D2B times, community hospitals and EMS systems have enabled emergency medical technicians (EMTs) and emergency department (ED) physicians to activate the CCLs without immediately consulting a cardiologist.

Objective

The purpose of this study is to determine the rate and main causes of inappropriate activation of the CCL which will aid in finding solutions to reduce this occurrence.

Method

This is a retrospective study, based on an electronic medical system review of all inappropriate CCL activation who presented to Providence Hospital and Medical Centers (PHMC) in Michigan, from January 2015 to July 2016.

Results

The CCL was activated 375 times for suspected STEMI. The false STEMI activation was identified in 47 patients which represents 12.5% of total CCL activation. The vast majority of this false activation was due to non-diagnostic electrocardiogram (ECG) that did not meet the STEMI criteria.

Conclusion

The subjective interpretation of the ECG by EMTs and ED physicians tend to show a wide variability, which may lead to higher-than-anticipated false activation rates of up to 36% in one study. Some studies had reported that up to 72% of inappropriate activations were caused by ECG misinterpretations. These false activations have ramifications that lead to both clinical and financial costs.

Diagnostic accuracy of prehospital electrocardiograms interpreted remotely by emergency physicians in myocardial infarction patients

BACKGROUND

Prehospital 12‑lead electrocardiogram (ECG) is the most widely used screening tool for recognition of ST-segment elevation myocardial infarction (STEMI). However, prehospital diagnosis of STEMI based solely on ECGs can be challenging.

OBJECTIVES

To evaluate the ability of emergency department (ED) physicians to accurately interpret prehospital 12‑lead ECGs from a remote location.

METHODS

All suspected prehospital STEMI patients who were transported by EMS and underwent angiography between 2006 and 2014 were included. We reviewed prehospital ECGs and grouped them based on: 1) presence or absence of a culprit artery lesion following angiography; and 2) whether they met the 3rd Universal Definition of Myocardial Infarction. We also described characteristics of ECGs that were misinterpreted by ED physicians.

RESULTS

A total of 625 suspected STEMI cases were reviewed. Following angiography, 94% (590/625) of patients were found having a culprit artery lesion, while 6% (35/625) did not. Among these 35 patients, 24 had ECGs that mimicked STEMI criteria and 9 had non-ischemic signs. Upon ECG reinterpretation, 92% (577/625) had standard STEMI criteria while 8% (48/625) did not. Among these 48 patients, 35 had ischemic signs ECGs and 13 did not. Characteristics of misinterpreted ECGs included pericarditis, early repolarization, STE > 1 mm (1‑lead only), and negative T-wave.

CONCLUSIONS

Remote interpretation of prehospital 12‑lead ECGs by ED physicians was a useful diagnostic tool in this EMS system. Even if the rate of ECG misinterpretation is low, there is still room for ED physicians operating from a remote location to improve their ability to accurately diagnose STEMI patients.

Multicentre analysis of current ST-elevation myocardial infarction acute care pathways

BACKGROUND

Rapid reperfusion with percutaneous coronary intervention (PCI) is vital for patients with ST segment elevation myocardial infarction (STEMI). However, the guideline-recommended time targets are regularly exceeded. The goal of this study was to gain insight into how Dutch PCI centres try to achieve these time targets by comparing their care processes with one another and with the European guideline-recommended process. In addition, accelerating factors perceived by care providers were identified.

METHODS

In this multiple case study, interviews with STEMI care providers were conducted, transcribed and used to create process descriptions per centre. Analyses consisted of within-case and between-case analyses of the processes. Accelerating factors were identified by means of open and axial coding.

RESULTS

In total, 28 interviews were conducted in six PCI centres. The centres differed from the guideline-recommended process on, for example, additional, unavoidable patient routings and monitoring delays, and from one another on the communication of diagnostic information (eg, transmitting all, only ambiguous or no ECGs) and catheterisation room preparation. These differences indicated diverging choices to maintain a balance between speed and diagnostic accuracy. Factors perceived by care providers as accelerating the process included trust in the tentative diagnosis, and avoiding unnecessary intercaregiver consultations. The combination of processes and accelerating factors were summarised in a model.

CONCLUSIONS

Numerous differences in processes between PCI centres were identified. Several time-saving strategies were applied by PCI centres, however, in different configurations. To further improve the care for patients with STEMI, best practices can be shared between centres and countries.

Interfacility Transfer Directly to the Neuroangiography Suite in Acute Ischemic Stroke Patients Undergoing Thrombectomy

BACKGROUND AND PURPOSE

In patients identified at referring facilities with acute ischemic stroke caused by a large vessel occlusion, bypassing the emergency department (ED) with direct transport to the neuroangiography suite may safely shorten reperfusion times.

METHODS

We conducted a single-center retrospective review of consecutive patients transferred to our facility for consideration of endovascular therapy. Patients were identified as admitted directly to the neuroangiography suite (DAN), transferred to the ED before intra-arterial therapy (ED-IA), and transferred to the ED but did not receive IA therapy (ED-IV).

RESULTS

A retrospective review of a prospectively maintained database of transfer patients between January 2013 and October 2016 with large vessel occlusions identified 108 ED-IV patients and 261 patients who underwent mechanical thrombectomy (DAN=111 patients and ED-IA=150 patients). There were no differences in baseline characteristics among the 3 groups. The median computed tomography ASPECTS (Alberta Stroke Program Early CT Score) was lower in the ED-IV group versus the ED-IA and DAN groups (8 versus 9; P=0.001). In the DAN versus ED-IA cohort, there were comparable rates of TICI2b/3 recanalization and access to recanalization time. There was significantly faster hospital arrival to groin access time in the DAN cohort (81 minutes versus 22 minutes; P=0.001). Functional independence at 90 days was comparable in the DAN versus ED-IA cohorts but worse in the ED-IV group (43% versus 44% versus 22%; P=0.001).

CONCLUSIONS

DAN is safe, feasible, and associated with faster times of hospital arrival to recanalization. The clinical benefit of this approach should be assessed in a prospective randomized trial.

Frequency and factors associated with inappropriate for intervention cardiac catheterization laboratory activation

BACKGROUND

Current guidelines emphasize timely coronary intervention with a door to balloon time of ≤90min for favorable survival impact after STEMI. Efforts to achieve these targets may result in unnecessary emergent angiography for inappropriate activations.

OBJECTIVE

Evaluate the frequency, trend and factors which are significantly associated with inappropriate for intervention cardiac catheterization laboratory (CCL) activation.

METHODS

We analyzed 1764 consecutive emergent CCL activation for possible ST segment elevation myocardial infarction (STEMI) between 7/2005 and 8/2013. Inappropriate for intervention activation was defined as negative STEMI (incorrect diagnosis: insignificant coronary lesion, not requiring any intervention) and inappropriate patients (true STEMI but poor CCL candidacy).

RESULTS

Inappropriate for intervention CCL activation occurred in 317 patients (17.9%): 292 incorrect diagnosis (negative STEMI diagnosis), 25 inappropriate patients, with no difference in the frequency based on time of the day (18.6% regular hours vs. 17.6% off-hours, p=0.6). On multivariable analysis, female gender (OR 1.9 [1.2-3.0]), African American race (OR 1.9[1.3-2.7]), and prior coronary artery bypass graft surgery (OR 3.6 [2.3-5.5]) were significantly associated with incorrect diagnosis (negative STEMI diagnosis) (all p<0.005) and hyperlipidemia (OR 0.2 [0.1-0.3]), tobacco use (OR 0.2 [0.1-0.3]), and stroke/TIA (OR 0.2 [0.1-0.4]) had a significant inverse association (all p<0.001). ST Elevation with no reciprocal depression and pericarditis/myocarditis were the most common ECG finding and etiology respectively.

CONCLUSION

Inappropriate for intervention CCL activation is not uncommon and should be closely monitored to maximize resource utilization. Females, African American patients with few or no risk factors and patients presenting ST elevation but no reciprocal depression constitute a population that may require attention.

Reperfusion therapy for ST-segment elevation myocardial infarction: has ECG information been underutilized?

This perspective makes a contentious viewpoint that ECG information is underutilized in ST-segment elevation myocardial infarction (STEMI) and the next breakthrough rests on its full utilization. This is to better diagnose difficult cases such as ST changes during bundle branch block, posterior ST elevation and right-sided ST elevation during normal conduction, and aVR ST elevation. More importantly, this is to better characterize the STEMI for tailored reperfusion. The proposal is to develop a system capable of recording from multiple electrodes that one can apply onto oneself, and having analysis coordinated centrally via phone-internet transmission. This provides 'longitudinal' in addition to 'cross-sectional' ECG information. STEMI will be classified on a gray-scale according to its potential size and speed of Q wave evolution. The hypothesis is that large rapidly progressive STEMI is best treated by on-site fibrinolysis with prompt transferral to a percutaneous coronary intervention center; while small stuttering STEMI is best treated by primary percutaneous coronary intervention despite a long delay.