Underuse of prehospital strategies to reduce time to reperfusion for ST-elevation myocardial infarction patients in 5 Canadian provinces

Outcomes of a Provincial Myocardial Infarction Reperfusion Strategy: A Population-Based, Retrospective Cohort Study

BACKGROUND

Fibrinolysis is an acceptable treatment for acute ST-segment elevation myocardial infarction (STEMI) when primary percutaneous coronary intervention (PCI) cannot be performed within 120 minutes. The American Heart Association has recommended Emergency Medical Services (EMS) interventions such as prehospital fibrinolysis (PHF), prehospital electrocardiogram (ECG), and hospital bypass direct to PCI center. Nova Scotia, Canada has incorporated these interventions into a unique province-wide approach to STEMI care. A retrospective cohort analysis comparing the primary outcome of 30-day mortality for patients receiving either prehospital or emergency department (ED) fibrinolysis (EDF) to patients transported directly by EMS from community or regional ED for primary PCI was conducted.

METHODS

This retrospective, population-based cohort study included all STEMI patients in Nova Scotia who survived to hospital admission from July 2011 through July 2013. Three provincial databases were used to collect demographic, 30-day mortality, hospital readmission, and rescue PCI data. The results were grouped and compared according to reperfusion strategy received: PHF, EDF, patients brought by ambulance via EMS direct to PCI (EMS to PCI), and ED to PCI (ED to PCI).

RESULTS

There were 1,071 STEMI patients included with 145 PHF, 606 EDF, 98 EMS to PCI, and 222 ED to PCI. There were no significant differences in 30-day mortality across groups (n, %): PHF 5(3); EDF 36(6); EHS to PCI <5(2); and ED to PCI 10(4); P = .28. There was no significant difference in patients receiving fibrinolysis who underwent rescue PCI.

CONCLUSIONS

Prehospital fibrinolysis incorporated into a province-wide approach to STEMI treatment is feasible with no observed difference in patient 30-day mortality outcomes observed.

Resource Use and Burden of Hospitalization, Outpatient, Physician, and Drug Costs in Short- and Long-term Care After Acute Myocardial Infarction

BACKGROUND

Little is known about the resource use and cost burden of acute myocardial infarction (AMI) beyond the index event. We examined resource use and care costs during the first and each subsequent year, among patients with incident AMI.

METHODS

Patients aged ≥18 years who were admitted with incident AMI at emergency departments or hospitals in Alberta, Canada, between April 2004 and March 2014 were included. Incident cases were defined as those without an AMI hospitalization in the previous 10 years. Inpatient, outpatient, practitioner claims, drug claims, and vital statistics were linked and follow-up data were available until March 2016. Resource use and care costs per patient for each year after the AMI were calculated.

RESULTS

The analysis included 41,210 patients with incident AMI (non-ST-segment elevation myocardial infarction [NSTEMI] = 50.8%, ST-segment elevation myocardial infarction = 36.8%, and undefined myocardial infarction [MI] = 12.5%). Resource use and care costs were highest during the first year. Compared with other MI groups, patients with ST-segment elevation myocardial infarction had more frequent outpatient visits (mean 1.64 vs 0.99 [NSTEMI] and 0.87 [undefined MI] visits) but spent fewer days in hospital (mean 7.72 vs 9.23 [NSTEMI] and 8.5 [undefined MI] days) during the first year. AMI costs were $19,842 during the first year and $845 per year for the next 5 years. Hospitalization costs accounted for the majority of costs during the first year (81.1%), whereas drug costs did for the next 5 years (62.1%).

CONCLUSIONS

The long-term annual cost burden of AMI is modest compared with care costs during the first year. Although hospitalization dominates first year costs, pharmaceuticals do so in the long term.

Effect of the number of request calls on the time from call to hospital arrival: a cross-sectional study of an ambulance record database in Nara prefecture, Japan

OBJECTIVES

In Japan, ambulance staff sometimes must make request calls to find hospitals that can accept patients because of an inadequate information sharing system. This study aimed to quantify effects of the number of request calls on the time interval between an emergency call and hospital arrival.

DESIGN AND SETTING

A cross-sectional study of an ambulance records database in Nara prefecture, Japan.

CASES

A total of 43 663 patients (50% women; 31.2% aged 80 years and over): (1) transported by ambulance from April 2013 to March 2014, (2) aged 15 years and over, and (3) with suspected major illness.

PRIMARY OUTCOME MEASURES

The time from call to hospital arrival, defined as the time interval from receipt of an emergency call to ambulance arrival at a hospital.

RESULTS

The mean time interval from emergency call to hospital arrival was 44.5 min, and the mean number of requests was 1.8. Multilevel linear regression analysis showed that ∼43.8% of variations in transportation times were explained by patient age, sex, season, day of the week, time, category of suspected illness, person calling for the ambulance, emergency status at request call, area and number of request calls. A higher number of request calls was associated with longer time intervals to hospital arrival (addition of 6.3 min per request call; p<0.001). In an analysis dividing areas into three groups, there were differences in transportation time for diseases needing cardiologists, neurologists, neurosurgeons and orthopaedists.

CONCLUSIONS

The study revealed 6.3 additional minutes needed in transportation time for every refusal of a request call, and also revealed disease-specific delays among specific areas. An effective system should be collaboratively established by policymakers and physicians to ensure the rapid identification of an available hospital for patient transportation in order to reduce the time from the initial emergency call to hospital arrival.

Initial experience with pre-activation of the cardiac catheterization lab and emergency room bypass for patients with ST-elevation myocardial infarction in Halifax, Nova Scotia

BACKGROUND

To determine whether pre-activation of the cardiac catheterization lab by Emergency Health Services (EHS) with a single call system in the field was associated with reduced time to reperfusion in patients with ST-Elevation Myocardial Infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI).

METHODS

Consecutive STEMI patients identified by EHS and subsequently taken to the Queen Elizabeth II Health Sciences Center (QEIIHSC) for PPCI between February 1, 2011 and January 30, 2013 were examined. Patients who had pre-activation of the catheterization lab from the field (pre-act group) after the acquisition of the LifeNet® system (Physio Control, Redmond Washington) were compared to those who had usual activation (routine group) prior to the acquisition of the LifeNet® system, for outcomes including treatment timeline data and mortality.

RESULTS

271 patients were included in the analysis, 149 patients in the pre-act group and 122 patients in the routine group. Door-to-device (DTD) times of less than 90min were achieved more frequently in the Pre-act group (91.9% vs. 62.2%; P<0.001). DTD time was shorter in the Pre-act group (48min IQR: 38 to 63min vs. 78min IQR: 64-101min; p=0.001) as was first medical contact-to-device (FMCTD) time (91min IQR: 78 to 106min vs. 115min IQR: 90 to 139min; P<0.001). False activation of the catheterization lab was infrequent (1.3%).

CONCLUSIONS

Implementation of catheterization lab pre-activation using the LifeNet® system was associated with more efficient reperfusion times as measured by reduced FMCTD and DTD times without excess false activation rates.

Adaptation and promotion of emergency medical service transportation for climate change

The purpose of this study is to find a proper prehospital transportation scenario planning of an emergency medical service (EMS) system for possible burdensome casualties resulting from extreme climate events. This project focuses on one of the worst natural catastrophic events in Taiwan, the 88 Wind-caused Disasters, caused by the Typhoon Morakot; the case of the EMS transportation in the Xiaolin village is reviewed and analyzed. The sequential-conveyance method is designed to promote the efficiency of all the ambulance services related to transportation time and distance. Initially, a proposed mobile emergency medical center (MEMC) is constructed in a safe location near the area of the disaster. The ambulances are classified into 2 categories: the first-line ambulances, which reciprocate between the MEMC and the disaster area to save time and shorten the working distances and the second-line ambulances, which transfer patients in critical condition from the MEMC to the requested hospitals for further treatment. According to the results, the sequential-conveyance method is more efficient than the conventional method for EMS transportation in a mass-casualty incident (MCI). This method improves the time efficiency by 52.15% and the distance efficiency by 56.02%. This case study concentrates on Xiaolin, a mountain village, which was heavily destroyed by a devastating mudslide during the Typhoon Morakot. The sequential-conveyance method for the EMS transportation in this research is not only more advantageous but also more rational in adaptation to climate change. Therefore, the findings are also important to all the decision-making with respect to a promoted EMS transportation, especially in an MCI.

Canada Acute Coronary Syndrome Risk Score: a new risk score for early prognostication in acute coronary syndromes

BACKGROUND

Despite the availability of several acute coronary syndrome (ACS) prognostic risk scores, there is no appropriate score for early-risk stratification at the time of the first medical contact with patients with ACS. The primary objective of this study is to develop a simple risk score that can be used for early-risk stratification of patients with ACS.

METHODS

We derived the risk score from the Acute Myocardial Infarction in Quebec and Canada ACS-1 registries and validated the risk score in 4 other large data sets of patients with ACS (Canada ACS-2 registry, Canada-GRACE, EFFECT-1, and the FAST-MI registries). The final risk score is named the Canada Acute Coronary Syndrome Risk Score (C-ACS) and ranged from 0 to 4, with 1 point assigned for the presence of each of these variables: age ≥75 years, Killip >1, systolic blood pressure <100 mm Hg, and heart rate >100 beats/min. The primary end points were short-term (inhospital or 30-day) and long-term (1- or 5-year) all-cause mortality.

RESULTS

The C-ACS has good predictive values for short- and long-term mortality of patients with ST-segment elevation myocardial infarction and non-ST-segment elevation ACS. The negative predictive value of a C-ACS score ≥1 is excellent at ≥98% (95% CI 0.97-0.99) for short-term mortality and ≥93% (95% CI 0.91-0.96) for long-term mortality. In other words, a C-ACS score of 0 can potentially identify correctly ≥97% short-term survivors and ≥91% long-term survivors.

CONCLUSION

The C-ACS risk score permits rapid stratification of patients with ACS. Because this risk score is simple and easy to memorize and calculate, it can be rapidly applied by health care professionals without advanced medical training.

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.

The utility of the prehospital electrocardiogram

OBJECTIVES

The 12-lead electrocardiogram (ECG) can capture valuable information in the prehospital setting. By the time patients are assessed by an emergency department (ED) physician, their symptoms and any ECG changes may have resolved. We sought to determine whether the prehospital electrocardiogram (pECG) could influence ED management and how often the pECG was available to and reviewed by the ED physician.

METHODS

A retrospective medical record review was conducted on a random sample of patients ≥ 18 years who had a prehospital 12-lead ECG and were transported to one of two tertiary care centres. Data were recorded onto a standardized data extraction tool. Three investigators independently compared the pECG to the first ECG obtained in the ED after patient arrival at the hospital. Any abnormalities not present on the ED ECG were adjudicated to ascertain whether they had the potential to change ED management.

RESULTS

Of 115 ambulance runs selected, 47 had no pECG attached to the ambulance call record (ACR) and another 5 were excluded (one ST elevation myocardial infarction, one cardiac arrest, three ACR missing). Of the 63 pECGs reviewed, 16 (25%) showed changes not apparent on the initial ED ECG (κ  =  0.83; 95% CI 0.74-0.93), of which 12 had differences that might influence ED management (κ  =  0.76; 95% CI 0.72-0.82). Only one hospital record contained a copy of the pECG, despite the current protocol that paramedics print two copies of the pECG on arrival in the ED (one copy for the ACR and one to be handed to the medical personnel). None of 110 ED charts documented that the pECG was reviewed by the ED physician.

CONCLUSION

The pECG has the potential to influence ED management. Improvement in paramedic and physician documentation and a formal pECG handover process appear necessary.

Temporal changes in emergency department triage of patients with acute myocardial infarction and the effect on outcomes

BACKGROUND

All patients who present to an emergency department (ED) are triaged. The ED triage score may determine when patients are seen by a physician. Half of patients with acute myocardial infarction (AMI) were given a low priority score in Ontario in 2000/2001. We assessed the appropriateness of ED triage and its association with quality indicators and outcomes in a more recent AMI cohort and compared this with previous findings.

METHODS

We conducted a retrospective cohort study of a population-based cohort of patients with AMI admitted to 96 hospitals in Ontario, Canada, in 2004/2005. Outcome measures included rate of low-priority ED triage (score of 3, 4, or 5), compared with an earlier cohort (fiscal year 2000) at the same sites, and the adjusted effect of low-priority ED triage on door-to-electrocardiogram, door-to-needle, and door-to-balloon time; hospital length of stay (LOS); and mortality.

RESULTS

Among 6,605 patients with AMI, low-priority triage was less frequent than in the earlier cohort, at 33.3% versus 50.3%. In patients with ST-segment elevation myocardial infarction (STEMI), it was 25.9%, versus 43.8% previously. Between cohorts, the greatest improvement in triage occurred in patients with chest pain, in those seen at higher AMI volume EDs, and in ambulatory patients; patients seen at low AMI volume EDs, those with diabetes, and the elderly showed the least improvement. Being assigned a low-priority triage score was associated with an adjusted increase in median door-to-electrocardiogram and door-to-needle time of 12.2 (P < .001) and 20.7 minutes (P < .001), respectively, longer than in the earlier cohort (4.4 and 15.1 minutes). It was associated with hospital LOS >75th percentile (odds ratio [OR] 1.25, P < .001), and higher 90-day (OR 1.50, P = .02) and 1-year mortality (OR 1.37, P = .05) in patients with STEMI.

CONCLUSION

Emergency department triage of patients with AMI improved substantially over 5 years. For the third of patients with AMI who continue to receive a low priority score, including 25% of patients with STEMI, the associated delays in diagnosis and therapy were greater than previously and were associated with increased hospital LOS and mortality. Given the impact of this initial, cursory assessment, hospital systems should consider monitoring the quality of their ED triage.

Effect of time to electrocardiogram on time from electrocardiogram to fibrinolysis in acute myocardial infarction patients

OBJECTIVE

The American Heart Association (AHA) recommends a benchmark door-to-electrocardiogram (ECG) time of 10 minutes for acute myocardial infarction patients, but this is based on expert opinion (level of evidence C). We sought to establish an evidence-based benchmark door-to-ECG time.

METHODS

This retrospective cohort study used a population-based sample of patients who suffered an ST elevation myocardial infarction (STEMI) in Ontario between 1999 and 2001. Using cubic smoothing splines, we described (1) the relationship between door-to-ECG time and ECG-to-needle time and (2) the proportion of STEMI patients who met the benchmark door-to-needle time of 30 minutes based on their door-to-ECG time. We hypothesized nonlinear relationships and sought to identify an inflection point in the latter curve that would define the most efficient (benefit the greatest number of patients) door-to-ECG time.

RESULTS

In 2,961 STEMI patients, the median door-to-ECG and ECG-to-needle times were 8.0 and 27.0 minutes, respectively. There was a linear increase in ECG-to-needle time as the door-to-ECG time increased, up to approximately 30 minutes, after which the ECG-to-needle time remained constant at 53 minutes. The inflection point in the probability of achieving the benchmark door-to-needle time occurred at 4 minutes, after which it decreased linearly, with every minute of door-to-ECG time decreasing the average probability of achievement by 2.2%.

CONCLUSIONS

Hospitals that are not meeting benchmark reperfusion times may improve performance by decreasing door-to-ECG times, even if they are meeting the current AHA benchmark door-to-ECG time. The highest probability of meeting the reperfusion target time for fibrinolytic administration is associated with a door-to-ECG time of 4 minutes or less.

The effect of a charted history of depression on emergency department triage and outcomes in patients with acute myocardial infarction

BACKGROUND

Patients with acute myocardial infarction may have worse outcomes if they also have a history of depression. The early management of acute myocardial infarction is known to influence outcomes, and patients with a coexisting history of depression may be treated differently in the emergency department than those without one. Our goal was to determine whether having a charted history of depression was associated with a lower-priority emergency department triage score and worse performance on quality-of-care indices.

METHODS

We conducted a retrospective population-based cohort analysis involving patients with acute myocardial infarction admitted to 96 acute care hospitals in the province of Ontario from April 2004 to March 2005. We calculated the adjusted odds of low-priority triage (Canadian Emergency Department Triage and Acuity Scale score of 3, 4 or 5) for patients with acute myocardial infarction who had a charted history of depression. We compared these odds with those for patients having a charted history of asthma or chronic obstructive pulmonary disease (COPD). Secondary outcome measures were the odds of meeting benchmark door-to-electrocardiogram, door-to-needle and door-to-balloon times.

RESULTS

Of 6784 patients with acute myocardial infarction, 680 (10.0%) had a past medical history of depression documented in their chart. Of these patients, 39.1% (95% confidence interval [CI] 35.3%-42.9%) were assigned a low-priority triage score, as compared with 32.7% (95% CI 31.5%-33.9%) of those without a charted history of depression. The adjusted odds of receiving a low-priority triage score with a charted history of depression were 1.26 (p = 0.01) versus 0.88 (p = 0.23) with asthma and 1.12 (p = 0.24) with COPD. For patients with a charted history of depression, the median door-to-electrocardiogram time was 20.0 minutes (v. 17.0 min for the rest of the cohort), median door-to-needle time was 53.0 (v. 37.0) minutes, and median door-to-balloon time was 251.0 (v. 110.0) minutes. The adjusted odds of missing the benchmark time with a charted history of depression were 1.39 (p < 0.001) for door-to-electrocardiogram time, 1.62 (p = 0.047) for door-to-needle time and 9.12 (p = 0.019) for door-to-balloon time.

INTERPRETATION

Patients with acute myocardial infarction who had a charted history of depression were more likely to receive a low-priority emergency department triage score than those with other comorbidities and to have worse associated performance on quality indicators in acute myocardial infarction care.