Hospital process intervals, not EMS time intervals, are the most important predictors of rapid reperfusion in EMS Patients with ST-segment elevation myocardial infarction

Comparison of the outcomes of EMS vs. Non-EMS transport of patients with ST-segment elevation myocardial infarction (STEMI) in Southern Iran: a population-based study

BACKGROUND

In the medical management of acute myocardial infarction, the transport of patients and primary care provided by emergency medical technicians (EMTs) and paramedics are effective in reducing the mortality and disabilities. Therefore, the present study aimed to compare the outcomes of emergency medical services (EMS) vs. non-EMS transport of patients with ST-segment elevation myocardial infarction (STEMI) in southern Iran.

METHODS

This is an analytical, cross-sectional study. The study population consisted of the individuals registered in Fasa Registry on Acute Myocardial Infarction (FaRMI) in the south of Iran. 2244 patients with STEMI were included in the study. Statistical analyses were performed using Chi-Square test and independent t-test at a significance level of P < 0.05 in SPSS 22.

RESULTS

Out of the 2244 patients with STEMI, 1552 (69.16%) were male and 672 patients (29.94%) were female. 934(41.62%) patients used EMS transport to the hospital, while 1310 (58.37%) patients used non-EMS transport to the hospital. A total of 169 patients with STEMI (7.26%) expired (out-of-hospital cardiac arrest); of them, 113 (66.86%) patients did not use EMS transport to the hospital. Successful cardiopulmonary resuscitation (CPR) was performed on 52 patients who used EMS transport. 27 patients also received an effective DC shock due to ventricular fibrillation (VF). Of the total number of patients, 49 had a stroke; among them, 37(75.51%) patients did not use EMS transport.

CONCLUSION

In the present study, the death rate in patients with acute myocardial infarction who used EMS transport was lower than those who used non-EMS transport. The health system managers and policymakers in the healthcare systems are recommended to take the necessary measures to increase public health awareness and knowledge about the use of EMS and consequently reduce the death rate and complications of acute myocardial infarction.

Neutrophil crosstalk during cardiac wound healing after myocardial infarction

Myocardial infarction (MI) initiates an intense inflammatory response that induces neutrophil infiltration into the infarct region. Neutrophils commence the pro-inflammatory response that includes upregulation of cytokines and chemokines (e.g., interleukin-1 beta) and degranulation of pre-formed proteases (e.g., matrix metalloproteinases -8 and -9) that degrade existing extracellular matrix to clear necrotic tissue. An increase or complete depletion of neutrophils both paradoxically impair MI resolution, indicating a complex role of neutrophils in cardiac wound healing. Following pro-inflammation, the neutrophil shifts to a reparative phenotype that promotes inflammation resolution and aids in scar formation. Across the shifts in phenotype, the neutrophil communicates with other cells to coordinate repair and scar formation. This review summarizes our current understanding of neutrophil crosstalk with cardiomyocytes and macrophages during MI wound healing.

Evaluation of Door-to-Balloon Times After Implementation of a ST-Segment Elevation Myocardial Infarction Network

BACKGROUND

ST-segment elevation myocardial infarction (STEMI) requires prompt therapy. It is recommended for door-to-balloon (DTB) times to be less than 90 minutes. In the United States, some locations have difficulty meeting this goal.

OBJECTIVE

The objective of this study was to determine whether implementation of a STEMI network decreased DTB times at a large, STEMI-receiving, metropolitan academic hospital in the southeastern United States. Furthermore, differences among presentation types, including walk-in, emergency medical services, and transfers, were explored.

METHODS

A pre-post time series study of electronic medical record data was conducted to evaluate the efficacy of a STEMI network.

RESULTS

The sample included 127 patients with a diagnosis of STEMI, collected during 3 periods (T1, T2, and T3). Patients were primarily White (78.0%) and male (67.7%), with a mean (SD) age of 58.9 (13.9) years. The 1-way analysis of variance revealed a significant difference in overall DTB times, F2 = 11.66, P < .001. Post hoc comparisons indicated longer mean DTB times for T1 compared with T3 (P < .001) and T2 (P < .001). When exploring presentation type, 1-way analysis of variance revealed a significant difference in mean DTB times in transfer patients between T1 and T2 (P < .001) and T1 to T3 (P < .001). No other statistical differences were noted; however, all DTB times with the exception of T2 for emergency medical services presentation decreased.

CONCLUSIONS

Implementation of a STEMI network was effective at decreasing overall DTB times with patients who presented to the hospital with a diagnosis of STEMI.

Reperfused vs. nonreperfused myocardial infarction: when to use which model

There is a lack of understanding in the cardiac remodeling field regarding the use of nonreperfused myocardial infarction (MI) and reperfused MI in animal models of MI. This Perspectives summarizes the consensus of the authors regarding how to select the optimum model for your experiments and is a part of ongoing efforts to establish rigor and reproducibility in cardiac physiology research.

Impact of emergency medical service delays on time to reperfusion and mortality in STEMI

Objectives

To explore the relationship between emergency medical service (EMS) delay time, overall time to reperfusion and clinical outcome in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI).

Methods

This was a retrospective observational study of 2976 patients with STEMI who presented to EMS and underwent PPCI between January 2014 and December 2017. We performed multivariable logistic models to assess the relationship between EMS delay time and 30-day mortality and to identify factors associated with system delay time.

Results

EMS delay time accounted for the first half of total system delay (median=59 min (IQR=48–77)). Compared with those who survived, those who died had longer median EMS delay times (59 (IQR=11–74) vs 74 (IQR=57–98), p<0.001). EMS delay time was independently associated with a higher risk of mortality (adjusted OR 1.20; 95% CI 1.02 to 1.40, for every 30 min increase), largely driven by complicated patients with cardiogenic shock or cardiac arrest. Independent predictors of longer EMS delay times were older age, women, cardiogenic shock, cardiac arrest, prehospital notification and intensive care management. Although longer EMS delay times were associated with shorter door-to-balloon times, total system delay times increased with increasing EMS delay times.

Conclusion

Increasing EMS delay times, particularly those result from haemodynamic complications, increase total time to reperfusion and are associated with 30-day mortality after STEMI. All efforts should be made to monitor and reduce EMS delay times for timely reperfusion and better outcome.

Paramedic-initiated helivac to tertiary hospital for primary percutaneous coronary intervention: a strategy for improving treatment delivery times

Background

In regions of New Zealand without coronary catheterisation laboratory (CCL) facilities, patients presenting with ST-elevation myocardial infarction (STEMI) are often subjected to prolonged delays before receiving primary percutaneous coronary intervention (PPCI) if it is the chosen reperfusion strategy. Therefore, we aimed to trial a new process of paramedic-initiated helivac of STEMI patients from the field directly to the CCL.

Methods

Utilising a prospective observational approach, over a 48-month period, paramedics identified patients with a clinical presentation and electrocardiogram features consistent with STEMI and transported them directly to the regional air ambulance base for helivac to the CCL (flight time 30-35 minutes). These patients were compared to two historic STEMI cohorts either transported by paramedics to the region's local hospital or self-presenting, prior to helivac. The primary outcome measures were: first medical contact-to-balloon (FMCTB) time and accuracy of paramedic diagnosis. Secondary outcome measures were mortality at 30 days and six months, and hospital length of stay (LOS).

Results

A total of 92 patients underwent helivac for PPCI (mean age of 64 years, SD ±10.3). Median FMCTB time was 155 minutes (IQR 27) for the historic cohorts (n=57), versus 102 minutes (IQR 16) for the experimental cohort (n=35, P<0.001). Paramedic diagnosis showed a sensitivity of 97% (95% CI: 85 to 99) and a specificity of 100% (95% CI: 84 to 100) with no inappropriate CCL activations. No significant difference was observed between groups in terms of 30 day and 6-month mortality. Hospital LOS was significantly shorter among the experimental cohort (P=0.01).

Conclusions

Paramedic-initiated helivac of STEMI patients from the field directly to the CCL for PPCI is safe and feasible and can significantly improve time-to-treatment to within benchmark timeframes, resulting in reduced hospital LOS.

Emergency medical service delays in ST-elevation myocardial infarction: a meta-analysis

OBJECTIVES

To evaluate emergency medical services (EMS) delays and their impact on time to treatment and mortality in patients with ST-elevation myocardial infarction (STEMI).

METHOD

We collected data on EMS time intervals from published studies across five electronic databases. The primary EMS interval was the time in minutes between first medical contact and arrival at hospital door (FMC-to-door time). Secondary intervals were other components of EMS delay. Weighted means were measured using random-effects models. Meta-regression was used to identify factors associated with EMS delays and to assess the impact of EMS delay on the proportion of patients treated within90 min and mortality.

RESULTS

Two independent reviewers included 100 studies (125 343 patients) conducted in 20 countries. The weighted mean FMC-to-door time was 41 min (n=101 646; 95% CI 39 to 43, range 21-88). However, substantial heterogeneity was observed with each interval, which could be explained by region and urban classification, distance to hospital and method of ECG interpretation. In a meta-regression adjusted for door-to-balloon time, a 10 min increase in FMC-to-door time was associated with a 10.6% (95% CI 7.6% to 13.5%; p<0.001) reduction in the proportion of patients treated within 90 min. Shorter EMS delay was significantly associated with lower short-term mortality in patients receiving prehospital thrombolysis (p=0.018).

CONCLUSION

EMS delays account for half of the total system delay in STEMI. There is a fourfold global variation in EMS delays, which are not completely explained by differences in system characteristics. Reducing unexplained variation could yield improvements in the time to treatment and outcome of STEMI patients.

PROSPERO REGISTRATION NUMBER

CRD42017074118.

Outcomes by Mode of Transport of ST Elevation MI Patients in the United Arab Emirates

INTRODUCTION

The purpose of this multicenter study was to assess differences in demographics, medical history, treatment times, and follow-up status among patients with ST-elevation myocardial infarction (STEMI), who were transported to the hospital by emergency medical services (EMS) or by private vehicle, or were transferred from other medical facilities.

METHODS

This multicenter study involved the collection of both retrospective and prospective data from 455 patients admitted to four hospitals in Abu Dhabi. We collected electronic medical records from EMS and hospitals, and conducted interviews with patients in person or via telephone. Chi-square tests and Kruskal-Wallis tests were used to examine differences in variables by mode of transportation.

RESULTS

Results indicated significant differences in modes of transportation when considering symptom-onset-to-balloon time (p < 0.001), door-to-balloon time (p < 0.001), and health status at six-month and one-year follow-up (p < 0.001). Median times (interquartile range) for patients transported by EMS, private vehicle, or transferred from an outside facility were as follows: symptom-onset-to-balloon time in hours, 3.1 (1.8-4.3), 3.2 (2.1-5.3), and 4.5 (3.0-7.5), respectively; door-to-balloon time in minutes, 70 (48-78), 81 (64-105), and 62 (46-77), respectively. In all cases, EMS transportation was associated with a shorter time to treatment than other modes of transportation. However, the EMS group experienced greater rates of in-hospital events, including cardiac arrest and mortality, than the private transport group.

CONCLUSION

Our results contribute data supporting EMS transportation for patients with acute coronary syndrome. Although a lack of follow-up data made it difficult to draw conclusions about long-term outcomes, our findings clearly indicate that EMS transportation can speed time to treatment, including time to balloon inflation, potentially reducing readmission and adverse events. We conclude that future efforts should focus on encouraging the use of EMS and improving transfer practices. Such efforts could improve outcomes for patients presenting with STEMI.

Overall ED efficiency is associated with decreased time to percutaneous coronary intervention for ST-segment elevation myocardial infarction

BACKGROUND

Performance of percutaneous coronary intervention (PCI) within 90 minutes of hospital arrival for ST-segment elevation myocardial infarction patients is a commonly cited clinical quality measure. The Centers for Medicare and Medicaid Services use this measure to adjust hospital reimbursement via the Value-Based Purchasing Program. This study investigated the relationship between hospital performance on this quality measure and emergency department (ED) operational efficiency.

METHODS

Hospital-level data from Centers for Medicare and Medicaid Services on PCI quality measure performance was linked to information on operational performance from 272 US EDs obtained from the Emergency Department Benchmarking Alliance annual operations survey. Standard metrics of ED size, acuity, and efficiency were compared across hospitals grouped by performance on the door-to-balloon time quality measure.

RESULTS

Mean hospital performance on the 90-minute arrival to PCI measure was 94.0% (range, 42-100). Among hospitals failing to achieve the door-to-balloon time performance standard, median ED length of stay was 209 minutes, compared with 173 minutes among those hospitals meeting the benchmark standard (P < .001). Similarly, median time from ED patient arrival to physician evaluation was 39 minutes for hospitals below the performance standard and 23 minutes for hospitals at the benchmark standard (P < .001). Markers of ED size and acuity, including annual patient volume, admission rate, and the percentage of patients arriving via ambulance did not vary with door-to-balloon time.

CONCLUSION

Better performance on measures associated with ED efficiency is associated with more timely PCI performance.

Association between prehospital electrocardiogram use and patient home distance from the percutaneous coronary intervention center on total reperfusion time in ST-segment-elevation myocardial infarction patients: a retrospective analysis from the national cardiovascular data registry

BACKGROUND

Current guidelines recommend ≤90 minutes from first medical contact to percutaneous coronary intervention (FMC2B) for ST-segment-elevation myocardial infarction (STEMI) patients. We evaluated the relationship between patient home distance from a percutaneous coronary intervention (PCI) center, prehospital electrocardiogram (ECG) use, and FMC2B time among patients with STEMI.

METHODS

We performed a retrospective cohort study including all STEMI patients in the ACTION-Get With The Guidelines registry from July 1, 2008, to September 30, 2012, who were transported by ambulance to a PCI center. Patient home distance was defined as the driving distance from the patient's home zip code to the PCI center address. Distance was classified into tertiles, and linear regression was used to characterize the interaction between prehospital ECG use and patient home distance with respect to FMC2B time.

RESULTS

Of the 29,506 STEMI patients, 19,690 (67%) received a prehospital ECG. The median patient home distance to the PCI center was 11.0 miles among patients with and 9.9 miles among those without a prehospital ECG. Prehospital ECGs were associated with a 10-minute reduction in the FMC2B time (P < .0001), which was consistent across distance tertiles (11 vs 11 vs 10 minutes). The association between prehospital ECGs and shorter FMC2B was attenuated by 0.8 minute for every 10-mile increase in distance (interaction P = .0002).

CONCLUSIONS

Prehospital ECGs are associated with a 10-minute reduction in the FMC2B time. However, patient home distance from a PCI center does not substantially change this association.

Information on myocardial ischemia and arrhythmias added by prehospital electrocardiograms

BACKGROUND

The prehospital electrocardiogram (ECG) allows earlier identification of acute ST-segment elevation myocardial infarction (STEMI). Its utility for detection of other acute cardiac events, as well as for transient ST-segment abnormalities no longer present when the first hospital ECG is performed, is not well characterized.

OBJECTIVE

We sought to examine whether the prehospital ECG adds supplemental information to the first ECG obtained in hospital, by comparing data on possible cardiac ischemia and arrhythmias provided by the two ECGs, in ambulance patients later diagnosed as having cardiac disorders, including STEMI.

METHODS

Ambulance personnel acquired 12-lead ECGs for patients suspected of having an acute ischemic event, prior to transport to hospital. The first emergency department 12-lead ECG was provided by medical records at the receiving hospital, and the principal hospital diagnosis for the event was extracted from chart data. Two cardiologists, blinded to the hospital diagnosis, provided their consensus interpretation of 1,209 pairs of ECGs, noting the presence or absence of specific abnormalities on each tracing.

RESULTS

Among the 82 patients who had an eventual hospital diagnosis of STEMI, the study cardiologists identified 71 with ST-segment elevations on the ECGs they examined. The vast majority of these (97%) were observed on both ECGs, but the prehospital ECG showed ST-segment elevation for two additional patients (3%). No additional instances were seen only on the hospital ECG. Among the 116 patients with a hospital diagnosis of non-ST-segment elevation myocardial infarction (NSTEMI), the cardiologists identified 36 with ST-segment depressions: 28 (78%) of these were present on both ECGs, seven (19%) only on the prehospital ECG, and one (3%) only on the hospital ECG. Among the 567 patients with any cardiac hospital diagnosis, the cardiologists identified 87 with arrhythmias: 73 (84%) on both ECGs, 12 (14%) only on the prehospital ECG, and two (2%) only on the hospital ECG.

CONCLUSIONS

Beyond identifying ST-segment elevation earlier, prehospital ECGs detect important transient abnormalities, information not otherwise available from the first emergency department ECG. These data can expedite diagnosis and clinical management decisions among patients suspected of having an acute cardiac event. The prehospital ECG should be fully integrated into emergency medicine practice.

Clinical events and treatment in prehospital patients with ST-segment elevation myocardial infarction

BACKGROUND

Little is known about clinically important events and advanced care treatment that patients with ST-segment elevation myocardial infarction (STEMI) encounter in the prehospital setting.

OBJECTIVES

We sought to determine the proportion of community patients with STEMI who experienced a clinically important event or received advanced care treatment prior to arrival at a designated percutaneous coronary intervention (PCI) laboratory or emergency department (ED).

METHODS

We reviewed 487 consecutive community patients with STEMI between May 2008 and June 2009. All patients were geographically within a single large "third-service" urban emergency medical services (EMS) system and were transported by paramedics with an advanced care scope of practice. We recorded predefined clinically important events and advanced care treatment that occurred in patients being transported directly to a PCI laboratory or ED (group 1) or interfacility transfer to a PCI laboratory (group 2).

RESULTS

One or more clinically important events occurred in 92 of 342 (26.9%) group 1 patients and nine of 145 (6.2%) group 2 patients. The most common were sinus bradycardia, hypotension, and cardiac arrest. Additionally, 33 of 342 (9.6%) group 1 and nine of 145 (6.2%) group 2 patients received one or more advanced care treatments. The most common were administration of morphine and administration of atropine. Eight group 1 patients and three group 2 patients received cardiopulmonary resuscitation (CPR) or defibrillation.

CONCLUSIONS

Clinically important events and advanced care treatment are common in community STEMI patients undergoing prehospital transport or interfacility transfer to a PCI center. Several patients required CPR or defibrillation. Further research is needed to define the clinical experience of STEMI patients during the out-of-hospital phase and the scope of practice required of EMS providers to safely manage these patients.