Rationale for establishing regional ST-elevation myocardial infarction receiving center (SRC) networks

Development of a unified national database of primary percutaneous coronary intervention centers with co-located emergency departments, 2020

BACKGROUND

Although primary percutaneous coronary intervention (pPCI) is the preferred intervention for ST-elevation myocardial infarction (STEMI), not all patients are admitted directly to an emergency department (ED) with 24/7/365 pPCI capabilities. This is partly due to a lack of a national system of known pPCI-capable EDs. Our objective was to create a unified, national database of confirmed 24/7/365 pPCI centers co-located in hospitals with EDs.

METHODS

We compiled all hospitals designated as Chest Pain Centers with Primary PCI by the American College of Cardiology's (ACC) National Clinical Data Registry (NCDR), all STEMI Receiving Centers designated by the American Heart Association's (AHA) Mission: Lifeline registry, and all state-designated pPCI-capable hospitals and designation criteria from state departments of health. We matched ACC, AHA, and state-designated facilities to those in the 2019 National ED Inventory (NEDI)-USA database to identify all EDs in pPCI-capable hospitals.

RESULTS

Overall, 467 hospitals were recognized as Chest Pain Centers with Primary PCI by ACC, 293 hospitals were recognized as being STEMI Receiving Centers by AHA, and 827 hospitals were confirmed to be pPCI-capable by state designations and operated 24/7/365. Together, there were 1,178 EDs (21% of 5,587 total) co-located in pPCI-capable hospitals operating 24/7/365.

CONCLUSIONS

There is substantial heterogeneity in cardiac systems of care, with large regional systems existing alongside local state-led initiatives. We created a unified national database of confirmed 24/7/365 pPCI centers co-located in hospitals with EDs. This data set will be valuable for future cardiac systems research and improving access to pPCI.

Emergency Interhospital Transfer of Patients With ST-Segment-Elevation Myocardial Infarction: Call 9-1-1-The American Heart Association Mission: Lifeline Program

The American Heart Association Mission: Lifeline program objectives are to improve the quality of care and outcomes for patients with ST-segment-elevation myocardial infarction. Every minute of delay in treatment adversely affects 1-year mortality. Transfer of patients safely and timely to hospitals with primary percutaneous coronary intervention capability is needed to improve outcomes. But treatment times continue to show delays, especially during interhospital transfers. A simple 3-step process of an interhospital "Call 9-1-1" protocol may expedite this process. This STAT TRANSFER process uses a systems approach that considers diverse ways in which patients access care, how EMS responds and determines destinations, how referring hospital transfers are performed, urban and rural differences, and how receiving hospitals prepare for an incoming patient with ST-segment-elevation myocardial infarction. This initiative suggests a strategy to reduce variability in interhospital transfer times using a STAT TRANSFER and a Call 9-1-1 process in a system of care that involves all stakeholders.

Combined therapy with dapagliflozin and entresto offers an additional benefit on improving the heart function in rat after ischemia-reperfusion injury

BACKGROUND

This study tested whether combined dapagliflozin and entresto treatment would be superior to either one alone for preserving the left-ventricular ejection-fraction (LVEF) in rat after ischemia-reperfusion (IR) injury.

METHODS AND RESULTS

In vitro flow-cytometric result showed that the intracellular and mitochondrial reactive oxygen species and mitochondrial permeability transition pore, and protein levels of oxidative-stress/DNA-damaged markers [NADPH-oxidase-1 (NOX-1)/NOX-2/oxidized-protein/γ-H2A-histone-family member X (γ-H2AX)] were significantly higher in hydrogen peroxide (H₂O₂) (300μM)-treated H9C2 cells as compared with the controls that were significantly reversed in sacubitril/valsartan and dapagliflozin therapy in the same H₂O₂-treated condition, whereas the protein expressions of antioxidants [Sirtuin-1 (SIRT1)/SIRT3/superoxide dismutase/catalase/glutathione peroxidase) exhibited an opposite pattern among the groups (all p<0.001). Adult-male-Sprague-Dawley rat (n=40) were equally categorized into group 1 (sham-operated control), group 2 (IR), group 3 (IR+dapagliflozin/20mg/kg/orally at 3h and post-days 1/2/3 after IR), group 4 (IR+entresto/100mg/kg/orally at 3h and post-days 1/2/3 after IR) and group 5 (IR+dapagliflozin+entresto) and the hearts were harvested by day 3 after IR. The 3^rd day's LVEF was highest in group 1, lowest in group 2 and significantly higher in group 5 than in groups 3/4, but it was similar between the latter two groups (p<0.001). The protein expressions of oxidative-stress (NOX-1/NOX-2/oxidized protein), fibrotic (transforming-growth factor-ß/phosphorylated-Smad3), apoptotic [mitochondrial-Bax/cleaved-caspase-3/cleaved-poly (ADP-ribose) polymerase], mitochondria/DNA damaged (cytosolic-cytochrome-C/γ-H2AX), pressure-overload/heart-failure [brain natriuretic peptide (BNP)/ß-myosin heavy chain] and autophagic (ratio of meiotic cyclins CLB3-II/CLB3-I) biomarkers, and the upstream (high-mobility group box 1/Toll-like receptor-4/MyD88/phosphorylated-nuclear factor-κB and downstream [interleukin (IL)-1ß/IL-6/tumor necrosis factor-α] inflammatory signalings revealed an antithetical features of LVEF among the groups (all p<0.0001). The cellular levels of inflammatory (myeloperoxidase+/CD68+), pressure-overload/heart-failure (BNP+) and DNA-damage (γ-H2AX+) biomarkers as well as infarct area demonstrated an opposite pattern of LVEF among the groups (all p<0.0001).

CONCLUSION

Incorporated entresto-dapagliflozin treatment was superior to either one alone on protecting the heart against IR injury.

Reperfusion Therapy Optimization in Acute Myocardial Infarction with ST-Segment Elevation using WhatsApp®-Based Telemedicine

BACKGROUND

About 40% of patients with ST-segment elevation myocardial infarction (STEMI) in Brazil do not receive reperfusion therapy.

OBJECTIVE

The use of a telemedicine network based on WhatsApp® could increase the percentage of patients receiving reperfusion therapy.

METHODS

A cross-sectional study analyzed outcomes before and after the organization of a telemedicine network to send the electrocardiogram via WhatsApp® of patients suspected of STEMI from 25 municipalities that are members of the Regional Health Department of Ribeirão Preto (DRS-XIII) to a tertiary hospital, which could authorize immediate patient transfer using the same system. The analyzed outcomes included the percentage of patients who received reperfusion therapy and the in-hospital mortality rate. A p value < 0.05 was considered statistically significant.

RESULTS

The study compared 82 patients before (February 1, 2016 to January 31, 2018) with 196 patients after this network implementation (February 1, 2018 to January 31, 2020). After implementing this network, there was a significant increase in the proportion of patients who received reperfusion therapy (60% vs. 92%), relative risk (RR): 1.594 [95% confidence interval (CI) 1.331 - 1.909], p < 0.0001 and decrease in the in-hospital mortality rate (13.4% vs. 5.6%), RR: 0.418 [95%CI 0.189 - 0.927], p = 0.028.

CONCLUSION

The use of WhatsApp®-based telemedicine has led to an increase in the percentage of patients with STEMI who received reperfusion therapy and a decrease in the in-hospital mortality rate.

Regional Systems of Care in ST Elevation Myocardial Infarction

ST-segment elevation myocardial infarction is a medical emergency with significant health care delivery challenges to ensure rapid triage and treatment. Several developments over the past decades have led to improved care delivery, decreased time to reperfusion, and decreased mortality. Still, significant challenges remain to further optimize the delivery of care for this patient population.

Optimizing Safety for Surgical Patients Undergoing Interhospital Transfer

Interhospital transfers play a key role in ensuring that patients receive necessary care. However, patients who are transferred between hospitals are a vulnerable population, and outcomes of transferred patients are suboptimal. Despite the critical nature of interhospital transfers, only limited effort has been dedicated to standardization and improvement of the transfer process. Studying and adapting quality improvement efforts directed at other transitions of care, particularly those that cross between different facilities and care teams "such as the transition from hospital to home or extended care facilities" may improve the care of surgical patients transferred between acute care institutions.

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.

Cancellation of the Cardiac Catheterization Lab After Activation for ST-Segment-Elevation Myocardial Infarction

BACKGROUND

Prehospital ECG-based cardiac catheterization laboratory (CCL) activation for ST-segment-elevation myocardial infarction reduces door-to-balloon times, but CCL cancellations (CCL^X) remain a challenging problem. We examined the reasons for CCL^X, clinical characteristics, and outcomes of patients presenting as ST-segment-elevation myocardial infarction activations who receive emergent coronary angiography (EA) compared with CCL^X.

METHODS AND RESULTS

We reviewed all consecutive CCL activations between January 1, 2012, and December 31, 2014 (n=1332). Data were analyzed comparing 2 groups stratified as EA (n=466) versus CCL^X (n=866; 65%). Reasons for CCL^X included bundle branch block (21%), poor-quality prehospital ECG (18%), non-ST-segment-elevation myocardial infarction ST changes (18%), repolarization abnormality (13%), and arrhythmia (8%). A multivariate logistic regression model using age, peak troponin, and initial ECG findings had a high discriminatory value for determining EA versus CCL^X (C statistic, 0.985). CCL^X subjects were older and more likely to be women, have prior coronary artery bypass grafting, or a paced rhythm ( P<0.0001 for all). All-cause mortality did not differ between groups at 1 year or during the study period (mean follow-up, 2.186±1.167 years; 15.8% EA versus 16.2% CCL^X; P=0.9377). Cardiac death was higher in the EA group (11.8% versus 3.0%; P<0.0001). After adjusting for clinical variables associated with survival, CCL^X was associated with an increased risk for all-cause mortality during the study period (hazard ratio, 1.82; 95% CI, 1.28-2.59; P=0.0009).

CONCLUSIONS

In this study, prehospital ECG without overreading or transmission lead to frequent CCL^X. CCL^X subjects differ with regard to age, sex, risk factors, and comorbidities. However, CCL^X patients represent a high-risk population, with frequently positive cardiac enzymes and similar short- and long-term mortality compared with EA. Further studies are needed to determine how quality improvement initiatives can lower the rates of CCL^X and influence clinical outcomes.

Effect of Specialized Critical Care Transport Unit on Short-Term Mortality of Critically ILL Patients Undergoing Interhospital Transport

Objective: To minimize risk and prevent harmful incidents during interhospital transport, the critical care transport unit service called Seoul Mobile Intensive Care Unit (SMICU) was organized and initiated its service within the city of Seoul. We sought to evaluate the effectiveness of critical care transport units on outcomes of critically ill patients undergoing interhospital transport in Seoul. Methods: A retrospective observational case-control study was designed to evaluate the effectiveness of critical care transport units on outcomes of critically ill patients undergoing interhospital transport. ED patients transported from other hospitals in Seoul during 2016 were identified in the National Emergency Department Information System (NEDIS) and according to use of the SMICU. One-to-one propensity matching was performed to balance covariates between groups. The association of SMICU transport on survival outcome was calculated in a multivariable logistic regression model. Results: Among 42,188 ED patients transported from other hospitals in 2016, 482 (1.1%) of patients were transported by SMICU. Patients transported by SMICU had a higher proportion of severe emergency disease and use of a mechanical ventilator. The adjusted odds ratio for 24-hour mortality after interhospital transport was 0.45 (95% CI: 0.26-0.81) in total cohort and was 0.34 (95% CI: 0.16-0.71) in a one-to-one propensity-matched cohort. Conclusions: Transport by specialized critical care transport unit for patients undergoing interhospital transport was associated with lower 24-hour mortality, demonstrating the benefits of the SMICU.

Percutaneous coronary intervention in patients with acute coronary syndrome in Chinese Military Hospitals, 2011-2014: a retrospective observational study of a national registry

OBJECTIVES

Interventional treatment of patients with acute coronary syndrome (ACS) is surging dramatically in China in recent years, whereas nationwide assessments of the quality of percutaneous coronary intervention (PCI) procedural performance and outcomes are scarce. We aimed to provide an updated and real-world overview of the performance of PCI in patients with ACS since 2011 in China after the China PEACE study from 2001 to 2011.

METHODS

In this cross-sectional study, data were extracted from the National Registry of Cardiovascular Intervention in Military Hospitals database to create a national sample of 144 659 patients with ACS undergoing PCI at 117 military hospitals in all regions of China from calendar years 2011-2014. Patient characteristics, procedural performance, PCI outcomes and adverse events and temporal changes were analysed.

RESULTS

During 2011-2014, patients with ACS undergoing PCI increased dramatically. Small numbers of high-volume hospitals performed the majority of PCI procedures. However, only half of these patients were adequately covered and proportions for the use of assisted devices and novel medications were relatively small. Radial artery access was still increasing with time. Primary PCIs were performed on 45.4% ST-segment elevation myocardial infarction patients with PCI procedures. 3.8% lesion vessels involve left main artery. Implanted stents, the overall complications and in-hospital mortality were decreasing remarkably.

CONCLUSIONS

In Chinese military hospitals, interventional resources were limited with great regional disparities, there are still gaps to be filled to better serve patients with ACS. Our findings can serve as an indispensable supplement to a more comprehensive understanding of the practice of contemporary cardiac intervention in China.

Combined Therapy with SS31 and Mitochondria Mitigates Myocardial Ischemia-Reperfusion Injury in Rats

Myocardial ischemia-reperfusion (IR) injury contributes to adverse cardiac outcomes after myocardial ischemia, cardiac surgery, or circulatory arrest. In this study, we evaluated the ability of combined SS31-mitochondria (Mito) therapy to protect heart cells from myocardial IR injury. Adult male SD rats (n = 8/each group) were randomized: group 1 (sham-operated control), group 2 (IR, 30-min ischemia/72 h reperfusion), group 3 (IR-SS31 (2 mg intra-peritoneal injection at 30 min/24 h/48 h after IR)), group 4 (IR-mitochondria (2 mg/derived from donor liver/intra-venous administration/30 min after IR procedure)), and group 5 (IR-SS31-mitochondria). In H9C2 cells, SS31 suppressed menadione-induced oxidative-stress markers (NOX-1, NOX-2, oxidized protein) while it increased SIRT1/SIRT3 expression and ATP levels. In adult male rats 72 h after IR, left ventricular ejection fraction (LVEF) was highest in sham-operated control animals and lowest in the IR group. LVEF was also higher in IR rats treated with SS31-Mito than untreated IR rats or those treated with Mito or SS31 alone. Areas of fibrosis/collagen-deposition showed the opposite pattern. Likewise, levels of oxidative-stress markers (NOX-1, NOX-2, oxidized protein), inflammatory markers (MMP-9, CD11, IL-1β, TNF-α), apoptotic markers (mitochondrial-Bax, cleaved-caspase-3, PARP), fibrosis markers (p-Smad3, TGF-β), DNA-damage (γ-H2AX), sarcomere-length, and pressure/volume overload markers (BNP, β-MHC) all showed a pattern opposite that of LVEF. Conversely, anti-apoptotic (BMP-2, Smad1/5) and energy integrity (PGC-1α/mitochondrial cytochrome-C) markers exhibited a pattern identical to that of LVEF. This study demonstrates that the combined SS31-Mito therapy is superior to either therapy alone for protecting myocardium from IR injury and indicates that the responsible mechanisms involved increased SIRT1/SIRT3 expression, which suppresses inflammation and oxidative stress and protects mitochondrial integrity.

Sex-based differences in quality of care and outcomes in a health system using a standardized STEMI protocol

BACKGROUND

Recent data from the National Cardiovascular Data Registry indicate that women with ST-segment-elevation myocardial infarction (STEMI) continue to have higher mortality and reported delays in treatment compared with men. We aimed to determine whether the sex difference in mortality exists when treatment disparities are reduced.

METHODS

Using a prospective regional percutaneous coronary intervention (PCI)-based STEMI system database with a standardized STEMI protocol, we evaluated baseline characteristics, treatment, and clinical outcomes of STEMI patients stratified by sex.

RESULTS

From March 2003 to January 2016, 4,918 consecutive STEMI patients presented to the Minneapolis Heart Institute at Abbott Northwestern Hospital regional STEMI system including 1,416 (28.8%) women. Compared with men, women were older (68.4 vs 60.9 years) with higher rates of hypertension (66.7% vs 55.7%), diabetes (21.7% vs 17.4%), and cardiogenic shock (11.5% vs 8.0%) (all P < .001). Pre-revascularization medications and PCI were performed with same frequencies, but women were less likely to receive statin or antiplatelet therapy at discharge. After age adjustment, women had similar in-hospital mortality to men (5.1% vs 4.8%, P = .60) despite slightly longer door-to-balloon time (95 vs 92 minutes, P = .004). Five-year follow-up confirmed absence of a sex disparity in age-adjusted survival post-STEMI.

CONCLUSIONS

Previously reported treatment disparities between men and women are diminished in a regional PCI-based STEMI system using a standardized STEMI protocol. No sex differences in short-term or long-term age-adjusted mortality are present in this registry despite some treatment disparities. These results suggest that STEMI health care disparities and mortality in women can be improved using STEMI protocols and systems.

Global Challenges and Solutions: Role of Telemedicine in ST-Elevation Myocardial Infarction Interventions

Major disparities exist between developed and developing countries in the management of acute myocardial infarction (AMI). These pronounced differences result in significantly increased morbidity and mortality from AMI in different regions of the world. Lack of infrastructure, insurance, facilities, and skilled personnel are the major constraints. Primary percutaneous coronary intervention has revolutionized the treatment of AMI; however, its global use is limited by the listed constraints. Telemedicine provides an efficient methodology that can hugely increase access and accuracy of AMI management.

Effectiveness of a Prehospital Wireless 12-Lead Electrocardiogram and Cardiac Catheterization Laboratory Activation for ST-Elevation Myocardial Infarction

The aim of the study was to determine the prevalence of false-positive and inappropriate cardiac catheterization laboratory (CCL) activation in patients suspected with ST-elevation myocardial infarction (STEMI) diverted to a percutaneous coronary intervention (PCI) facility after paramedics wireless 12-lead electrocardiogram transmission to an emergency physician at an online medical control center. This retrospective study collected data from medical records of patients with suspected STEMI from 2006 to 2014. It included demographics, coronaropathic risk factors, cardiac biomarkers, time from the first medical contact to treatment, and final diagnosis. Primary outcome was the rate of false-positive and inappropriate CCL activation. As secondary outcomes, we compared patient characteristics between cases of appropriate and inappropriate CCL activation, and we assessed the presence of cardiac biomarkers, time from first medical contact to start of PCI, and final diagnosis. Overall, 673 patients with suspected STEMI were included in the analysis. A total of 640 patients (95%) had coronarography, of which 10% (62 of 640) did not have a culprit coronary artery (false positive). Angiography was canceled for 5% (33 of 673) of patients. The total false-positive and inappropriate CCL activation rate was 14% (95 of 673). Average time from the first medical contact to the start of PCI was 47 ± 18.1 minutes. Unwanted CCL activations were more likely to involve men aged >65 years and patients with a history of coronary artery disease. In conclusion, our system of transmitted prehospital electrocardiography and STEMI interpretation by emergency physicians at an online medical control center showed a total false-positive and inappropriate CCL activation rate of 14% over the 8-year study period.

The impact of recommended percutaneous coronary intervention care on hospital outcomes for interhospital-transferred STEMI patients

BACKGROUND

Timely transfer and percutaneous coronary intervention (PCI) with or without thrombolysis are recommended by the American Heart Association (AHA) to care for ST-segment elevation myocardial infarction (STEMI) patients who present first to a non-PCI-capable hospital. This study was to evaluate the impact on in-hospital mortality of the compliance with guidelines regarding to the time of PCI for patients with STEMI who were transferred to a capable PCI hospital.

METHODS

We used the CArdioVAscular disease Surveillance data from November 2007 to December 2012 for this study. Adult patients who were diagnosed with STEMI and transferred from a primary hospital for PCI were included. Patients who underwent PCI or coronary artery bypass graft surgery in the primary hospital and patients with an unknown emergency department disposition were excluded. The main exposure was the AHA recommendation for reperfusion therapy. We tested the association between compliance with AHA and hospital mortality.

RESULTS

A total of 2078 patients were analyzed, 30.0% of whom were treated in compliance with the guidelines, whereas the remaining 70.0% were not. Thrombolysis was performed in 7.9% and 0.8% (P value < .01) and hospital mortality was 5.0% and 6.8% (P value = .11) in the compliant and violence groups, respectively. The adjusted odds ratios (95% confidence intervals) of the compliant group for hospital mortality were 0.75 (0.46-1.21), respectively. A sensitivity analysis of symptom onset to arrival time was a trend for a beneficial effect in the compliant group.

CONCLUSIONS

Among the patients who were transferred for STEMI care, undergoing PCI as recommended by the AHA was not associated with a mortality benefit, but the patients whose symptom onset to hospital arrival time was within 30 minutes showed an association between compliance and lower mortality.

Characteristics of ST Elevation Myocardial Infarction Patients Who Do Not Undergo Percutaneous Coronary Intervention After Prehospital Cardiac Catheterization Laboratory Activation

OBJECTIVES

To assess the clinical and electrocardiographic characteristics of patients diagnosed with ST elevation myocardial infarction (STEMI) that are associated with an increased likelihood of not undergoing percutaneous coronary intervention (PCI) after prehospital Cardiac Catheterization Laboratory activation in a regional STEMI system.

METHODS

We performed a retrospective analysis of prehospital Cardiac Catheterization Laboratory activations in Mecklenburg County, North Carolina, between May 2008 and March 2011. Data were extracted from the prehospital patient record, the prehospital electrocardiogram, and the regional STEMI database. The independent variables of interest included objective patient characteristics as well as documented cardiac history and risk factors. Analysis was performed using descriptive statistics and logistic regression.

RESULTS

Two hundred thirty-one prehospital activations were included in the analysis. Five independent variables were found to be associated with an increased likelihood of not undergoing PCI: increasing age, bundle branch block, elevated heart rate, left ventricular hypertrophy, and non-white race. The variables with the most significance were any type of bundle branch block [adjusted odds ratios (AOR), 5.66; 95% confidence interval (CI), 1.91-16.76], left ventricular hypertrophy (AOR, 4.63; 95% CI, 2.03-10.53), and non-white race (AOR, 3.53; 95% CI, 1.76-7.08). Conversely, the only variable associated with a higher likelihood of undergoing PCI was the presence of arm pain (AOR, 2.94; 95% CI, 1.36-6.25).

CONCLUSIONS

Several of the above variables are expected electrocardiogram mimics; however, the decreased rate of PCI in non-white patients highlights an area for investigation and process improvement. This may guide the development of prehospital STEMI protocols, although avoiding false positive and inappropriate activations.

Importance of hospital entry: walk-in STEMI and primary percutaneous coronary intervention

INTRODUCTION

Patients with ST elevation myocardial infarction (STEMI) require rapid identification and triage to initiate reperfusion therapy. Walk-in STEMI patients have longer treatment times compared to emergency medical service (EMS) transported patients. While effective triage of large numbers of critically ill patients in the emergency department is often cited as the reason for treatment delays, additional factors have not been explored. The purpose of this study was to evaluate baseline demographic and clinical differences between walk-in and EMS-transported STEMI patients and identify factors associated with prolonged door to balloon (D2B) time in walk-in STEMI patients.

METHODS

We performed a retrospective review of 136 STEMI patients presenting to an urban academic teaching center from January 2009 through December 2010. Baseline demographics, mode of hospital entry (walk-in versus EMS transport), treatment times, angiographic findings, procedures performed and in-hospital clinical events were collected. We compared walk-in and EMS-transported STEMI patients and identified independent factors of prolonged D2B time for walk-in patients using stepwise logistic regression analysis.

RESULTS

Walk-in patients (n=51) were more likely to be Latino and presented with a higher heart rate, higher systolic blood pressure, prior history of diabetes mellitus and were more likely to have an elevated initial troponin value, compared to EMS-transported patients. EMS-transported patients (n=64) were more likely to be white and had a higher prevalence of left main coronary artery disease, compared to walk-in patients. Door to electrocardiogram (ECG), ECG to catheterization laboratory (CL) activation and D2B times were significantly longer for walk-in patients. Walk-in patients were more likely to have D2B time >90 minutes, compared to EMS- transported patients; odds ratio 3.53 (95% CI 1.03, 12.07), p=0.04. Stepwise logistic regression identified hospital entry mode as the only independent predictor for prolonged D2B time.

CONCLUSION

Baseline differences exist between walk-in and EMS-transported STEMI patients undergoing primary percutaneous coronary intervention (PCI). Hospital entry mode was the most important predictor for prolonged treatment times for primary PCI, independent of age, Latino ethnicity, heart rate, systolic blood pressure and initial troponin value. Prolonged door to ECG and ECG to CL activation times are modifiable factors associated with prolonged treatment times in walk-in STEMI patients. In addition to promoting the use of EMS transport, efforts are needed to rapidly identify and expedite the triage of walk-in STEMI patients.

Inhibition of dipeptidyl peptidase-IV enzyme activity protects against myocardial ischemia-reperfusion injury in rats

Background

We investigated whether attenuating dipeptidyl peptidase-IV (DPP4) enzyme activity protected rat heart from ischemia-reperfusion (IR) injury (40-min left anterior descending coronary artery ligation followed by 72 h reperfusion).

Methods and results

Adult male Fischer 344 rats (n = 24) were equally divided into sham-control (WT-SC), WT-IR, and WT-IR-Sita (oral sitagliptin 400 mg/kg/day for 3 days) groups, whereas adult male DPP4-deficiency (DPP4^D) rats (n = 16) were equally divided into DPP4^D-SC and DPP4^D-IR groups. Animals were sacrificed at 72 h after reperfusion with collection of heart specimens. Infarct area (H&E), collagen deposition (Sirius-red stain), fibrotic area (Masson's trichrome), and fluorescent-ROS intensity (H₂DCFDA-labeling myocardium) of left ventricle were significantly higher in WT-IR than those in other groups, significantly higher in WT-IR-Sita and DPP4^D-IR groups than in WT-SC and DPP4^D-SC groups (all p < 0.001), but there was no difference between the latter two groups. Protein expressions of oxidative stress (oxidized protein), reactive oxygen species (NOX-1, NOX-2), inflammation (TNF-α, NF-κB, MMP-9, VCAM-1), apoptosis (mitochondrial Bax, cleaved caspase-3 and PARP), myocardial damage markers (cytosolic cytochrome-C, γ-H2AX), and number of inflammatory cells (CD14+, CD68+, CD40+ cells) showed a pattern identical to that of histological changes among all groups (all p < 0.005), whereas markers of anti-apoptosis (Bcl-2) and mitochondrial integrity (mitochondrial cytochrome-C) as well as left ventricular ejection fraction showed an opposite pattern (all p < 0.001). Protein expressions of anti-oxidants (HO-1, NQO-1), angiogenesis factors (SDF-1α, CXCR4), and glycogen-like-peptide-1-receptor were significantly higher inWT-IR-Sita and DPP4^D-IR than those in other groups (all p < 0.001).

Conclusion

Abrogation of DPP4 activity protects against myocardial IR injury and preserved heart function.

Paramedic specialization: a strategy for better out-of-hospital care

Demographic, economic, and political forces are driving significant change in the US health care system. Paramedics are a health profession currently providing advanced emergency care and medical transportation throughout the United States. As the health care system demands more team-based care in nonacute, community, interfacility, and tactical response settings, specialized paramedic practitioners could be a valuable and well-positioned resource to meet these needs. Currently, there is limited support for specialty certifications that demand appropriate education, training, or experience standards before specialized practice by paramedics. A fragmented approach to specialty paramedic practice currently exists across our country in which states, regulators, nonprofit organizations, and other health care professions influence and regulate the practice of paramedicine. Multiple other medical professions, however, have already developed effective systems over the last century that can be easily adapted to the practice of paramedicine. Paramedicine practitioners need to organize a profession-based specialty board to organize and standardize a specialty certification system that can be used on a national level.

Evaluation of a regional ST-elevation myocardial infarction primary percutaneous coronary intervention program at the Rouge Valley Health System

BACKGROUND

ST-elevation myocardial infarction (STEMI) remains the second leading cause of death in Canada. Primary percutaneous coronary intervention (PCI) has been recognized as an effective method for treating STEMI. Improved access to primary PCI can be achieved through the implementation of regional PCI centres, which was the impetus for implementing the PCI program in an east Toronto hospital in 2009. As such, the purpose of this study was to measure the efficacy of this program regional expansion.

METHODS

A retrospective review of 101 patients diagnosed with STEMI from May to Sept 2010 was conducted. The average door-to-balloon time for these STEMI patients was calculated and the door-to-balloon times using different methods of arrival were analyzed. Method of arrival was by one of three ways: paramedic initiated referral; patient walk-ins to PCI centre emergency department; or transfer after walk-in to community hospital emergency department.

RESULTS

The study found that mean door-to balloon time for PCI was 112.5 minutes. When the door-to-balloon times were compared across the three arrival methods, patients who presented by paramedic-initiated referral had significantly shorter door-to-balloon times, (89.5 minutes) relative to those transferred (120.9 minutes) and those who walked into a PCI centre (126.7 minutes) (p = 0.047).

CONCLUSIONS

The findings suggest that the partnership between the hospital and its EMS partners should be continued, and paramedic initiated referral should be expanded across Canada and EMS systems where feasible, as this level of coverage does not currently exist nationwide. Investments in regional centres of excellence and the creation of EMS partnerships are needed to enhance access to primary PCI.

Variable penetration of primary angioplasty in Europe--what determines the implementation rate?

Primary percutaneous coronary intervention (PPCI) is the recommended treatment for patients with acute ST-segment elevation myocardial infarction (STEMI). A survey conducted in 2008 in the European Society of Cardiology (ESC) countries reported that the annual incidence of hospital admissions for acute STEMI is around 800 patients per million inhabitants. The survey also showed that STEMI patients' access to reperfusion therapy and the use of PPCI or thrombolytic therapy (TT) vary considerably among countries. Northern, Western and Central Europe already had well-developed PPCI services, offering PPCI to 60-90% of all STEMI patients. Southern Europe and the Balkans were still predominantly using TT and had a higher proportion of patients who were left without any reperfusion treatment. The survey concluded that a nationwide PPCI strategy results in more patients being offered reperfusion therapy. To address the inequalities in STEMI patients' access to life-saving PPCI and to support the implementation of the ESC STEMI treatment guidelines in Europe, the Stent for Life (SFL) Initiative was launched jointly by the European Association of Percutaneous Cardiovascular Interventions (EAPCI) and EuroPCR in 2008. The aim of the SFL Initiative is to improve the delivery of life-saving PPCI for STEMI patients. Currently, 10 national cardiac societies support the SFL Initiative in their respective countries. SFL national action programmes have been developed and are being implemented in several countries. The formation of regional PPCI networks involving emergency medical services, non-PPCI hospitals and PPCI centres is considered to be a critical factor in implementing PPCI services effectively. Better monitoring of STEMI incidence and prospective registration of PPCI in all countries is required to document improvements in health care and to identify areas where further effort is required. Furthermore, studies on potential factors or characteristics that explain the national penetration of PPCI are needed. Such knowledge will be necessary to increase the effectiveness and efficiency of the implementation, and will be the first step in ensuring equal access to PPCI treatment for STEMI patients in Europe. Establishing the delivery of PPCI in an effective, high-quality and timely manner is a great challenge.

Emergency medical services management of ST-segment elevation myocardial infarction in the United States--a report from the American Heart Association Mission: Lifeline Program

OBJECTIVE

ST-segment elevation myocardial infarction (STEMI) is a major cause of morbidity and mortality in the United States. Emergency medical services (EMS) agencies play a critical role in its initial identification and treatment. We conducted this study to assess EMS management of STEMI care in the United States.

METHODS

A structured questionnaire was administered to leaders of EMS agencies to define the elements of STEMI care related to 4 core measures: (1) electrocardiogram (ECG) capability at the scene, (2) destination protocols, (3) catheterization laboratory activation before hospital arrival, and (4) 12-lead ECG quality review. Geographic areas were grouped into large metropolitan, small metropolitan, micropolitan, and noncore (or rural) by using Urban Influence Codes, with a stratified analysis.

RESULTS

Data were included based on responses from 5296 EMS agencies (36% of those in the United States) serving 91% of the US population, with at least 1 valid response from each of the 50 states and the District of Columbia. Approximately 63% of agencies obtained ECGs at the scene using providers trained in ECG acquisition and interpretation. A total of 46% of EMS systems used protocols to determine hospital destination, cardiac catheterization laboratory activation, and communications with the receiving hospital. More than 75% of EMS systems used their own agency funds to purchase equipment, train personnel, and provide administrative oversight. A total of 49% of agencies have quality review programs in place. In general, EMS systems covering higher population densities had easier access to resources needed to maintain STEMI systems of care. Emergency medical services systems that have adopted all 4 core elements cover 14% of the US population.

CONCLUSIONS

There are large differences in EMS systems of STEMI care in the United States. Most EMS agencies have implemented at least 1 of the 4 core elements of STEMI care, with many having implemented multiple elements.

Predictors of reperfusion delay in patients with ST elevation myocardial infarction self-transported to the hospital (from the American Heart Association's Mission: Lifeline Program)

Primary percutaneous coronary intervention for ST elevation myocardial infarction (STEMI) is beneficial if performed in a timely manner. Self-transport patients with STEMI have prolonged treatment times compared with Emergency Medical Services-transported patients. This study evaluated self-transport patients with STEMI undergoing primary percutaneous coronary intervention to identify factors associated with prolonged door-to-balloon (D2B) times. From January 2007 to March 2011, data for 13,379 self-transport patients with STEMI treated at 432 hospitals in the Acute Coronary Treatment Intervention Outcomes Network Registry-Get With The Guidelines Registry were evaluated. Patients with a D2B time >90 minutes were compared with those with D2B time ≤90 minutes. Factors associated with prolonged D2B (>90 minutes) were explored using logistic generalized estimating equations. The median (twenty-fifth, seventy-fifth percentiles) D2B time for the entire cohort was 72 minutes (58, 86), and 19% had a D2B time of >90 minutes. Over the study period, there was a significant increase in the percentage of patients achieving D2B time ≤90 minutes. There were significant baseline differences between patients with D2B time ≤ versus >90 minutes. The main factors associated with prolonged treatment time were off-hour presentation (weekends and 7 p.m. to 7 a.m. weekdays), not obtaining an electrocardiogram within 10 minutes of hospital arrival, previous coronary artery bypass surgery, black race, older age, and female gender. In conclusion, although prolonged delay from arrival to electrocardiographic acquisition is a modifiable factor contributing to prolonged D2B times among self-transport patients with STEMI, additional factors (age, race, and gender) indicate that historic disparities for cardiovascular care still persist in terms of contemporary metrics for STEMI reperfusion.

Reduction in STEMI transfer times utilizing a municipal "911" ambulance service

INTRODUCTION

The time interval from diagnosis to reperfusion therapy for patients experiencing ST-segment elevation myocardial infarction (STEMI) has a significant impact on morbidity and mortality.

HYPOTHESIS

It is hypothesized that the time required for interfacility patient transfers from a community hospital to a regional percutaneous coronary intervention (PCI) center using an Advanced Life Support (ALS) transfer ambulance service is no different than utilizing the "911" ALS ambulance.

METHODS

Quality assurance data collected by a tertiary care center cardiac catheterization program were reviewed retrospectively. Data were collected on all patients with STEMI requiring interfacility transfer from a local community hospital to the tertiary care center's PCI suite, approximately 16 miles away by ground, 12 miles by air. In 2009, transfers of patients with STEMI were redirected to the municipal ALS ambulance service, instead of the hospital's contracted ALS transfer service. Data were collected from January 2007 through May 2013. Temporal data were compared between transports initiated through the contracted ALS ambulance service and the municipal ALS service. Data points included time of initial transport request and time of ambulance arrival to the sending facility and the receiving PCI suite.

RESULTS

During the 4-year study period, 63 patients diagnosed with STEMI and transferred to the receiving hospital's PCI suite were included in this study. Mean times from the transport request to arrival of the ambulance at the sending hospital's emergency department were six minutes (95% CI, 4-7 minutes) via municipal ALS and 13 minutes (95% CI, 9-16 minutes) for the ALS transfer service. The mean times from the ground transport request to arrival at the receiving hospital's PCI suite when utilizing the municipal ALS ambulance and hospital contracted ALS ambulance services were 48 minutes (95% CI, 33-64 minutes) and 56 minutes (95% CI 52-59 minutes), respectively. This eight-minute period represented a 14% (P = .001) reduction in the mean transfer time to the PCI suite for patients transported via the municipal ALS ambulance.

CONCLUSION

In the appropriate setting, the use of the municipal "911" ALS ambulance service for the interfacility transport of patients with STEMI appears advantageous in reducing door-to-catheterization times.

Emergency medical services as a strategy for improving ST-elevation myocardial infarction system treatment times

BACKGROUND

Reducing delays in time to treatment is a key goal of ST-elevation myocardial infarction (STEMI) emergency care. Emergency medical services (EMS) are a critical component of the STEMI chain of survival.

STUDY OBJECTIVE

We sought to assess the impact of the careful integration of EMS as a strategy for improving systemic treatment times for STEMI.

METHODS

We conducted a study of all 747 nontransfer STEMI patients who underwent primary percutaneous coronary intervention (PCI) in Dallas County, Texas from October 1, 2010 through December 31, 2011. EMS leaders from 24 agencies and 15 major PCI receiving hospitals collected and shared common, de-identified patient data. We used 15 months of data to develop a generalized linear regression to assess the impact of EMS on two treatment metrics-hospital door to balloon (D2B) time, and symptom onset to arterial reperfusion (SOAR) time, a new metric we developed to assess total treatment times.

RESULTS

We found statistically significant reductions in median D2B (11.1-min reduction) and SOAR (63.5-min reduction) treatment times when EMS transported patients to the receiving facility, compared to self-transport. In addition, when trained EMS paramedics field-activated the cardiac catheterization laboratory using predefined specified protocols, D2B times were reduced by 38% (43 min) after controlling for confounding variables, and field activation was associated with a 21.9% reduction (73 min) in the mean SOAR time (both with p < 0.001).

CONCLUSION

Active EMS engagement in STEMI treatment was associated with significantly lower D2B and total coronary reperfusion times.

Enhancing the efficacy of delivering reperfusion therapy: a European and North American experience with ST-segment elevation myocardial infarction networks

Advances in technique and adjunctive medication have improved outcome of ST-segment elevation myocardial infarction (STEMI) patients. However, the timely delivery and administration of reperfusion strategies to all eligible patients remain challenging. Currently, up to one-third of eligible STEMI patients in industrialized countries worldwide receive no specific reperfusion treatment, a problem that is rectified by the development and implementation of STEMI networks, as also recommended by the latest European Society of Cardiology and American College of Cardiology/American Heart Association guidelines. Indeed, over the last 5 years, published figures demonstrate that STEMI networks increase the percentage of patients treated by any reperfusion strategy, and the percentage of patients receiving treatment within the recommended time frames has also improved, thereby reducing in-hospital and long-term mortality to very low levels. This manuscript demonstrates how STEMI networks can be adapted to local needs and circumstances against pre-existing barriers and despite the heterogeneity in local situations, patient's characteristics, treatment delays, and distances for transfer. Modern and efficacious networks must be prepared to offer both primary percutaneous coronary intervention and thrombolytic therapy, preferably prehospital, as long as primary percutaneous coronary intervention cannot be guaranteed to all individuals within the recommended timeline.

Integrated Regional Networks for ST-Segment–Elevation Myocardial Infarction Care in Developing Countries

Background—

Regionalized integrated networks for ST-segment–elevation myocardial infarction (STEMI) care have been proposed as a step forward in overcoming real-world obstacles, but data are lacking on its performance in developing countries. We describe an integrated regional STEMI network in Salvador, Bahia, Brazil.

Methods and Results—

The network was created in 2009. It was coordinated by the prehospital emergency medical service and encompassed the public emergency system (prehospital mobile units, community-based emergency units, general hospitals, and cardiology reference centers). The 12-lead ECGs are interpreted via telemedicine. This network operates as follows: The Telemedicine Center sends each ECG suggestive of STEMI to a Regional STEMI Alert Team, which, together with emergency medical services, offers support for thrombolysis or immediate transfer for primary percutaneous coronary intervention. In 14 months, there were 433 suspected victims, of which in 287 (76.5%) the STEMI could be confirmed (age, 62.1±12.5 years; 63.4% men). Most of them were self-transported. The median pain-to-admission time was 180 minutes (interquartile range, 90–473 minutes), and the median admission-to-ECG time was 159.5 minutes (interquartile range, 83.5–340 minutes). The median interval time between the ECG and the telemedicine report was 31 minutes (interquartile range, 21–44 minutes). For those who sought medical attention and had an ECG performed within 12 hours after symptoms onset (n=119), the reperfusion rate was 75.6% (34.4% by thrombolysis and 65.6% by primary percutaneous coronary intervention).

Conclusions—

Regional STEMI networks may be feasible in developing countries. Preliminary results showed this network to be effective, achieving primary reperfusion rtes comparable with those reported internationally despite the obstacles faced.

Why Does Primary Angioplasty Not Work in Registries? Quantifying the Susceptibility of Real-World Comparative Effectiveness Data to Allocation Bias

Background—

Meta-analysis of registries (comparative effectiveness research) shows that primary angioplasty and fibrinolysis have equivalent real-world survival. Yet, randomized, controlled trials consistently find primary angioplasty superior. Can unequal allocation of higher-risk patients in registries have masked primary angioplasty benefit?

Methods and Results—

First, we constructed a model to demonstrate the potential effect of allocation bias. We then analyzed published registries (55022 patients) for allocation of higher-risk patients (Killip class ≥1) to determine whether the choice of reperfusion therapy was affected by the risk level of the patient. Meta-regression was used to examine the relationship between differences in allocation of high-risk patient to primary angioplasty or fibrinolysis and mortality. Initial modeling suggested that registry outcomes are sensitive to allocation bias of high-risk patients. Across the registries, the therapy receiving excess high-risk patients had worse mortality. Unequal distribution of high-risk status accounted for most of the between-registry variance (adjusted R 2 meta =83.1%). Accounting for differential allocation of higher-risk patients, primary angioplasty gave 22% lower mortality (odds ratio, 0.78; 95% confidence interval, 0.64–0.97; P =0.029). We derive a formula, called the number needed to abolish, highlighting situations in which comparative effectiveness studies are particularly vulnerable to this bias.

Conclusions—

In ST-segment elevation myocardial infarction, clinicians’ preference for management of a few high-risk patients can shift mortality substantially. Comparative effectiveness research in any disease is vulnerable to this, especially diseases with an immediately identifiable high-risk subgroup that clinicians prefer to allocate to 1 therapy. For this reason, preliminary indications from registry-based comparative effectiveness research should be definitively tested by randomized, controlled trials.

Setting Up a Population-Based Program to Optimize ST-Segment Elevation Myocardial Infarction Care

The development of ST-segment elevation myocardial infarction (STEMI) systems of care at the city, region, or nation levels has not only improved the speed of reperfusion but also enhanced the reach of primary angioplasty to areas far from percutaneous coronary intervention (PCI) centers. Setting up a STEMI system of care is a sophisticated process that requires a solid PCI hospital and emergency medical services infrastructure, disciplined collaboration, and a focus on outcomes measurement and continuous quality improvement. This article reviews the accumulated evidence supporting the development of STEMI systems of care and offers practical insights into this process.

Regionalization of post-cardiac arrest care: implementation of a cardiac resuscitation center

BACKGROUND

Guidelines recommend standardized treatment of post-cardiac arrest patients to improve outcomes. However, the infrastructure, resources, and personnel required to meet the complex needs of cardiac arrest victims remain a barrier to care. Given that regionalization of time-dependent high-acuity illness is an emerging paradigm, the aim of the present study was to develop and implement a regionalized approach to post-cardiac arrest care.

METHODS

We performed a prospective observational study on all patients treated in a regionalized clinical pathway from November 2007 through June 2011. All patients were enrolled after admission to an urban academic medical center. Clinical data including arrest and treatment variables, complications, and outcome were collected on consecutive patients with the use of a preformatted standard data collection tool using Utstein criteria.

RESULTS

A total of 220 patients were enrolled; 127 (58%) patients were local direct admissions from our community, and 93 (42%) were transferred from 1 of 24 outlying referral hospitals. One hundred six (48%, 95% CI 38%-53%) patients survived to hospital discharge. The primary outcome of hospital survival with good neurologic function was observed in 94 (43%, 95% CI 32%-48%). There was no difference in survival with good neurologic outcome among local and referred patients. Overall 1-year survival was 44% (95% CI 38%-51%). Among patients discharged from the hospital with good neurologic function, 93% (95% CI 85%-97%) remained alive at 1 year.

CONCLUSION

Development of a regionalized approach to post-cardiac arrest care using previously established referral relationships is feasible, and implementation of such an approach was clinically effective in our region.

Systems of Care for ST-Segment–Elevation Myocardial Infarction: A Report From the American Heart Association’s Mission: Lifeline

Background—

National guidelines call for participation in systems to rapidly diagnose and treat ST-segment–elevation myocardial infarction (STEMI). In order to characterize currently implemented STEMI reperfusion systems and identify practices common to system organization, the American Heart Association surveyed existing systems throughout the United States.

Methods and Results—

A STEMI system was defined as an integrated group of separate entities focused on reperfusion therapy for STEMI within a geographic region that included at least 1 hospital that performs percutaneous coronary intervention and at least 1 emergency medical service agency. Systems meeting this definition were invited to participate in a survey of 42 questions based on expert panel opinion and knowledge of existing systems. Data were collected through the American Heart Association Mission: Lifeline website.

Between April 2008 and January 2010, 381 unique systems involving 899 percutaneous coronary intervention hospitals in 47 states responded to the survey, of which 255 systems (67%) involved urban regions. The predominant funding sources for STEMI systems were percutaneous coronary intervention hospitals (n = 320, 84%) and /or cardiology practices (n = 88, 23%). Predominant system characteristics identified by the survey included: STEMI patient acceptance at percutaneous coronary intervention hospital regardless of bed availability (N = 346, 97%); single phone call activation of catheterization laboratory (N = 335, 92%); emergency department physician activation of laboratory without cardiology consultation (N = 318, 87%); data registry participation (N = 311, 84%); and prehospital activation of the laboratory through emergency department notification without cardiology notification (N = 297, 78%). The most common barriers to system implementation were hospital (n = 139, 37%) and cardiology group competition (n = 81, 21%) and emergency medical services transport and finances (n = 99, 26%).

Conclusions—

This survey broadly describes the organizational characteristics of collaborative efforts by hospitals and emergency medical services to provide timely reperfusion in the United States. These findings serve as a benchmark for existing systems and should help guide healthcare teams in the process of organizing care for patients with STEMI.

Ground emergency medical services requests for helicopter transfer of ST-segment elevation myocardial infarction patients decrease medical contact to balloon times in rural and suburban settings

OBJECTIVES

  ST-segment elevation myocardial infarction (STEMI) care is time-dependent. Many STEMI patients require interhospital helicopter transfer for percutaneous coronary intervention (PCI) if ground emergency medical services (EMS) initially transport the patient to a non-PCI center. This investigation models potential time savings of ground EMS requests for helicopter EMS (HEMS) transport of a STEMI patient directly to a PCI center, rather than usual transport to a local hospital with subsequent transfer.

METHODS

  Data from a multicenter retrospective chart review of STEMI patients transferred for primary PCI by a single HEMS agency over 12 months were used to model medical contact to balloon times (MCTB) for two scenarios: a direct-to-scene HEMS response and hospital rendezvous after ground EMS initiation of transfer.

RESULTS

  Actual MCTB median time for 36 hospital-initiated transfers was 160 minutes (range = 116 to 321 minutes). Scene response MCTB median time was estimated as 112 minutes (range = 69 to 187 minutes). The difference in medians was 48 minutes (95% confidence interval [CI] = 33 to 62 minutes). Hospital rendezvous MCTB median time was estimated as 113 minutes (range = 74 to 187 minutes). The difference in medians was 47 minutes (95% CI = 32 to 62 minutes). No patient had an actual MCTB time of less than 90 minutes; in the scene response and hospital rendezvous scenarios, 2 of 36 (6%) and 3 of 36 (8%), respectively, would have had MCTB times under 90 minutes.

CONCLUSIONS

  In this setting, ground EMS initiation of HEMS transfers for STEMI patients has the potential to reduce MCTB time, but most patients will still not achieve MCTB time of less than 90 minutes.

Differentiating ST-elevation myocardial infarction from nonischemic ST-elevation in patients with chest pain

Current guidelines state that patients with compatible symptoms and ST-segment elevation (STE) in ≥2 contiguous electrocardiographic leads should undergo immediate reperfusion therapy. Aggressive attempts at decreasing door-to-balloon times have led to more frequent activation of primary percutaneous coronary intervention (pPCI) protocols. However, it remains crucial to correctly differentiate STE myocardial infarction (STEMI) from nonischemic STE (NISTE). We assessed the ability of experienced interventional cardiologists in determining whether STE represents acute STEMI or NISTE. Seven readers studied electrocardiograms of consecutive patients showing STE. Patients with left bundle branch block or ventricular rhythms were excluded. Readers decided if, based on electrocardiographic results, they would have activated the pPCI protocol. If NISTE was chosen, readers selected from 12 possible explanations as to why STE was present. Of 84 patients, 40 (48%) had adjudicated STEMI. The percentage for which readers recommended pPCI varied (33% to 75%). Readers' sensitivity and specificity ranged from 55% to 83% (average 71%) and 32% to 86% (average 63%), respectively. Positive and negative predictive values ranged from 52% to 79% (average 66%) and 67% to 79% (average 71%), respectively. Broad inconsistencies existed among readers as to the chosen reasons for NISTE classification. In conclusion, we found wide variations in experienced interventional cardiologists in differentiating STEMI with a need for pPCI from NISTE.