Regional Systems of Care Demonstration Project: American Heart Association Mission: Lifeline STEMI Systems Accelerator

BACKGROUND

Up to 50% of patients fail to meet ST-segment-elevation myocardial infarction (STEMI) guideline goals recommending a first medical contact-to-device time of <90 minutes for patients directly presenting to percutaneous coronary intervention-capable hospitals and <120 minutes for transferred patients. We sought to increase the proportion of patients treated within guideline goals by organizing coordinated regional reperfusion plans.

METHODS

We established leadership teams, coordinated protocols, and provided regular feedback for 484 hospitals and 1253 emergency medical services (EMS) agencies in 16 regions across the United States.

RESULTS

Between July 2012 and December 2013, 23 809 patients presented with acute STEMI (direct to percutaneous coronary intervention hospital: 11 765 EMS transported and 6502 self-transported; 5542 transferred). EMS-transported patients differed from self-transported patients in symptom onset to first medical contact time (median, 47 versus 114 minutes), incidence of cardiac arrest (10% versus 3%), shock on admission (11% versus 3%), and in-hospital mortality (8% versus 3%; P<0.001 for all comparisons). There was a significant increase in the proportion of patients meeting guideline goals of first medical contact-to-device time, including those directly presenting via EMS (50% to 55%; P<0.001) and transferred patients (44%-48%; P=0.002). Despite regional variability, the greatest gains occurred among patients in the 5 most improved regions, increasing from 45% to 57% (direct EMS; P<0.001) and 38% to 50% (transfers; P<0.001).

CONCLUSIONS

This Mission: Lifeline STEMI Systems Accelerator demonstration project represents the largest national effort to organize regional STEMI care. By focusing on first medical contact-to-device time, coordinated treatment protocols, and regional data collection and reporting, we were able to increase significantly the proportion of patients treated within guideline goals.

Comparison of performance on Hospital Compare process measures and patient outcomes between hospitals that do and do not participate in Acute Coronary Treatment and Intervention Outcomes Network Registry-Get With The Guidelines

BACKGROUND

Acute Coronary Treatment and Intervention Outcomes Network Registry-Get With The Guidelines (ACTION Registry-GWTG) was designed to measure and improve the treatment and outcomes of patients with acute myocardial infarction (AMI), yet it is unknown whether performance of Medicare Hospital Compare metrics and outcomes differ between hospitals participating versus those not participating in the registry.

METHODS

Using 2007 to 2010 Hospital Compare data, we matched participating to nonparticipating hospitals based on teaching status, size, percutaneous coronary intervention capability, and baseline (2007) Hospital Compare AMI process measure performance. We used linear mixed modeling to compare 2010 Hospital Compare process measure adherence, 30-day risk-adjusted mortality, and readmission rates. We repeated these analyses after stratification according to baseline performance level.

RESULTS

Compared with nonparticipating hospitals, those participating were larger (median 288 vs 139 beds, P < .0001), more often teaching hospitals (18.8% vs 6.3%, P < .0001), and more likely had interventional catheterization lab capabilities (85.7% vs 34.0%, P < .0001). Among 502 matched pairs of participating and nonparticipating hospitals, we found high levels of process measure adherence in both 2007 and 2010, with minimal differences between them. Rates of 30-day mortality and readmission in 2010 were also similar between both groups. Results were consistent across strata of baseline performance level.

CONCLUSIONS

In this observational analysis, there were no significant differences in the performance of Hospital Compare process measures or outcomes between hospitals in Acute Coronary Treatment and Intervention Outcomes Network Registry-Get With The Guidelines and other hospitals not in the registry. However, baseline performance on the Hospital Compare process measures was very high in both groups, suggesting the need for new quality improvement foci to further improve patient outcomes.

American Heart Association Response to the 2015 Institute of Medicine Report on Strategies to Improve Cardiac Arrest Survival

The American Heart Association (AHA) commends the recently released Institute of Medicine (IOM) report, Strategies to Improve Cardiac Arrest Survival: A Time to Act (2015). The AHA recognizes the unique opportunity created by the report to meaningfully advance the objectives of improving outcomes for sudden cardiac arrest. For decades, the AHA has focused on the goal of reducing morbidity and mortality from cardiovascular disease though robust support of basic, translational, clinical, and population research. The AHA also has developed a rigorous process using the best available evidence to develop scientific, advisory, and guideline documents. These core activities of development and dissemination of scientific evidence have served as the foundation for a broad range of advocacy initiatives and programs that serve as a foundation for advancing the AHA and IOM goal of improving cardiac arrest outcomes. In response to the call to action in the IOM report, the AHA is announcing 4 new commitments to increase cardiac arrest survival: (1) The AHA will provide up to $5 million in funding over 5 years to incentivize resuscitation data interoperability; (2) the AHA will actively pursue philanthropic support for local and regional implementation opportunities to increase cardiac arrest survival by improving out-of-hospital and in-hospital systems of care; (3) the AHA will actively pursue philanthropic support to launch an AHA resuscitation research network; and (4) the AHA will cosponsor a National Cardiac Arrest Summit to facilitate the creation of a national cardiac arrest collaborative that will unify the field and identify common goals to improve survival. In addition to the AHA’s historic and ongoing commitment to improving cardiac arrest care and outcomes, these new initiatives are responsive to each of the IOM recommendations and demonstrate the AHA’s leadership in the field. However, successful implementation of the IOM recommendations will require a timely response by all stakeholders identified in the report and a coordinated approach to achieve our common goal of improved cardiac arrest outcomes.

Association of Bystander and First-Responder Intervention With Survival After Out-of-Hospital Cardiac Arrest in North Carolina, 2010-2013

IMPORTANCE

Out-of-hospital cardiac arrest is associated with low survival, but early cardiopulmonary resuscitation (CPR) and defibrillation can improve outcomes if more widely adopted.

OBJECTIVE

To examine temporal changes in bystander and first-responder resuscitation efforts before arrival of the emergency medical services (EMS) following statewide initiatives to improve bystander and first-responder efforts in North Carolina from 2010-2013 and to examine the association between bystander and first-responder resuscitation efforts and survival and neurological outcome.

DESIGN, SETTINGS, AND PARTICIPANTS

We studied 4961 patients with out-of-hospital cardiac arrest for whom resuscitation was attempted and who were identified through the Cardiac Arrest Registry to Enhance Survival (2010-2013). First responders were dispatched police officers, firefighters, rescue squad, or life-saving crew trained to perform basic life support until arrival of the EMS.

EXPOSURES

Statewide initiatives to improve bystander and first-responder interventions included training members of the general population in CPR and in use of automated external defibrillators (AEDs), training first responders in team-based CPR including AED use and high-performance CPR, and training dispatch centers in recognition of cardiac arrest.

MAIN OUTCOMES AND MEASURES

The proportion of bystander and first-responder resuscitation efforts, including the combination of efforts between bystanders and first responders, from 2010 through 2013 and the association between these resuscitation efforts and survival and neurological outcome.

RESULTS

The combination of bystander CPR and first-responder defibrillation increased from 14.1% (51 of 362; 95% CI, 10.9%-18.1%) in 2010 to 23.1% (104 of 451; 95% CI, 19.4%-27.2%) in 2013 (P < .01). Survival with favorable neurological outcome increased from 7.1% (82 of 1149; 95% CI, 5.8%-8.8%) in 2010 to 9.7% (129 of 1334; 95% CI, 8.2%-11.4%) in 2013 (P = .02) and was associated with bystander-initiated CPR. Adjusting for age and sex, bystander and first-responder interventions were associated with higher survival to hospital discharge. Survival following EMS-initiated CPR and defibrillation was 15.2% (30 of 198; 95% CI, 10.8%-20.9%) compared with 33.6% (38 of 113; 95% CI, 25.5%-42.9%) following bystander-initiated CPR and defibrillation (odds ratio [OR], 3.12; 95% CI, 1.78-5.46); 24.2% (83 of 343; 95% CI, 20.0%-29.0%) following bystander CPR and first-responder defibrillation (OR, 1.70; 95% CI, 1.06-2.71); and 25.2% (109 of 432; 95% CI, 21.4%-29.6%) following first-responder CPR and defibrillation (OR, 1.77; 95% CI, 1.13-2.77).

CONCLUSIONS AND RELEVANCE

Following a statewide educational intervention on rescusitation training, the proportion of patients receiving bystander-initiated CPR and defibrillation by first responders increased and was associated with greater likelihood of survival. Bystander-initiated CPR was associated with greater likelihood of survival with favorable neurological outcome.

Cardiac arrest and clinical characteristics, treatments and outcomes among patients hospitalized with ST-elevation myocardial infarction in contemporary practice: A report from the National Cardiovascular Data Registry

BACKGROUND

Cardiac arrest (CA) is a major complication of patients with ST-elevation myocardial infarction (STEMI). Its prevalence and prognostic impact in contemporary US practice has not been well assessed.

METHODS

We evaluated STEMI patients included in the National Cardiovascular Data Registry (NCDR) Acute Coronary Treatment Intervention Outcomes Network Registry-Get With the Guidelines (ACTION Registry-GWTG) from 4/1/11 to 6/30/12. Patient clinical characteristics, treatments, and inhospital outcomes were compared by the presence or absence of CA on first medical contact-either before hospital arrival or upon presentation to the ACTION hospital.

RESULTS

Of the 49,279 STEMI patients included, 3,716 (7.5%) had CA. Cardiac arrest patients were more likely to have heart failure (15.5% vs 6.9%) and shock (42.9% vs 4.9%) on presentation and higher median (25th and 75th percentiles) ACTION Registry-GWTG mortality risk scores (42 [32, 54] vs 32 [26, 38]) than non-CA patients (all P < .001). Primary percutaneous coronary intervention was performed in most patients with and without CA (76.7% vs 79.1%). Inhospital mortality was significantly higher in patients with than without CA (28.8% vs 4.0%; P < .001), both in patients who presented with cardiogenic shock (46.9% vs 27.1%; P < .001) and those without shock (15.4% vs 2.9%; P < .001). The ACTION Registry-GWTG inhospital mortality model underestimated mortality risk in CA patients; however, prediction significantly improved after adding CA to the model.

CONCLUSIONS

Almost 8% of STEMI patients present with CA. More than 25% die during the hospitalization, despite high use of primary percutaneous coronary intervention. Cardiogenic shock and CA frequently coexist. Our results suggest that development of systems of care and treatments for both STEMI and CA is needed to reduce the high mortality in these patients.

Predictors and progression of aortic stenosis in patients with preserved left ventricular ejection fraction

We aimed to characterize the hemodynamic progression of aortic stenosis (AS) in a contemporary unselected cohort of patients with preserved left ventricular ejection fraction. Current guidelines recommend echocardiographic surveillance of hemodynamic progression. However, limited data exist on the expected rate of progression and whether clinical variables are associated with accelerated progression in contemporarily managed patients with AS. We conducted a retrospective analysis of patients presenting with AS and explored the trajectory of AS mean gradient over time using generalized estimating equations and fit a longitudinal linear regression model with adjustment for baseline clinical variables. A total of 1,558 patients (median age 72; interquartile range 65 to 79) having mild (n = 982), moderate (n = 363), or severe AS (n = 213) were included. In patients with mild AS at baseline (n = 983), 303 (31%) had progressed to moderate/severe AS/AVR within 5 years of the index echo. In patients with moderate AS, 159 of 363 (44%) had progressed to severe AS/AVR within 2 years of the index echo. The annual change in mean gradient was dependent on baseline AS severity. Average annual increases in mean gradient were 6.8% (95% confidence interval 6.0 to 7.6) and 7.1% (95% confidence interval 4.8 to 9.3) in patients with mild and moderate AS, respectively. In the subset of patients with mild AS at baseline, age (p = 0.0310) and gender (p = 0.0270) had significant interaction with change in mean gradient over time. In patients with moderate AS, age (p <0.0001), gender (p = 0.0346), renal dysfunction (p = 0.0036), and hyperlipidemia (p = 0.0010) demonstrated significant interaction with change in mean gradient over time. In conclusion, although average disease progression was slower than previously reported, a significant proportion of patients with mild and moderate AS progressed to higher grades within the currently recommended time windows for echocardiographic follow-up.

Relationship of the distance between non-PCI hospitals and primary PCI centers, mode of transport, and reperfusion time among ground and air interhospital transfers using NCDR's ACTION Registry-GWTG: a report from the American Heart Association Mission: Lifeline Program

BACKGROUND

ST-segment myocardial infarction patients frequently present to non-percutaneous coronary intervention (PCI) hospitals and require interhospital transfer for primary PCI. The effect of distance and mode of transport to the PCI center and the frequency that recommended primary PCI times are met are not clear.

METHODS AND RESULTS

Data from the ACTION Registry(®)-GWTG™ were used to determine the distance between the Non-PCI and PCI center and first door time to balloon time based on transfer mode (ground and air) for patients having interhospital transfer for primary PCI. From July 1, 2008, to December 31, 2012, 17 052 ST-segment myocardial infarction patients were transferred to 413 PCI hospitals. The median distance from the non-PCI hospital to the primary PCI center was 31.9 miles (Q1, Q3: 19.1, 47.9; ground 25.2 miles; air 43.9 miles; P<0.001). At distances <40 miles, ground transport was the primary transport method, whereas at distances >40 miles air transport predominanted. Median first door time to balloon time time for patients transferred for primary PCI was 118 minutes (Q1, Q3: 95 152), with time for patients transported by air significantly longer (median 124 versus 113 minutes; respectively, P<0.001) than for patients transported by ground. Fifty-three percent of patients had a first door time to balloon time ≤120 minutes, with only 20% ≤90 minutes. A first door time to balloon time ≤120 minutes was more likely in ground than in air transport patients (57.0% versus 45.6%; P<0.001).

CONCLUSIONS

Interhospital transfer for primary PCI is associated with prolonged reperfusion times. These delays should prompt increased consideration of fibrinolytic therapy, emergency medical services hospital bypass protocols, and improved systems of care for ST-segment myocardial infarction patients requiring transfer.

Regional systems of care demonstration project: Mission: Lifeline STEMI Systems Accelerator: design and methodology

ST-segment elevation myocardial infarction (STEMI) systems of care have been associated with significant improvement in use and timeliness of reperfusion. Consequently, national guidelines recommend that each community should develop a regional STEMI care system. However, significant barriers continue to impede widespread establishment of regional STEMI care systems in the United States. We designed the Regional Systems of Care Demonstration Project: Mission: Lifeline STEMI Systems Accelerator, a national educational outcome research study in collaboration with the American Heart Association, to comprehensively accelerate the implementation of STEMI care systems in 17 major metropolitan regions encompassing >1,500 emergency medical service agencies and 450 hospitals across the United States. The goals of the program are to identify regional gaps, barriers, and inefficiencies in STEMI care and to devise strategies to implement proven recommendations to enhance the quality and consistency of care. The study interventions, facilitated by national faculty with expertise in regional STEMI system organization in partnership with American Heart Association representatives, draw upon specific resources with proven past effectiveness in augmenting regional organization. These include bringing together leading regional health care providers and institutions to establish common commitment to STEMI care improvement, developing consensus-based standardized protocols in accordance with national professional guidelines to address local needs, and collecting and regularly reviewing regional data to identify areas for improvement. Interventions focus on each component of the reperfusion process: the emergency medical service, the emergency department, the catheterization laboratory, and inter-hospital transfer. The impact of regionalization of STEMI care on clinical outcomes will be evaluated.

Stress cardiac MR imaging compared with stress echocardiography in the early evaluation of patients who present to the emergency department with intermediate-risk chest pain

PURPOSE

To compare the utility and efficacy of stress cardiac magnetic resonance (MR) imaging and stress echocardiography in an emergency setting in patients with acute chest pain (CP) and intermediate risk of coronary artery disease (CAD).

MATERIALS AND METHODS

Written informed consent was obtained from all patients. This HIPAA-compliant study was approved by the institutional review board for research ethics. Sixty patients without history of CAD presented to the emergency department with intermediate-risk acute CP and were prospectively enrolled. Patients underwent both stress cardiac MR imaging and stress echocardiography in random order within 12 hours of presentation. Stress imaging results were interpreted clinically immediately (blinded interpretation was performed months later), and coronary angiography was performed if either result was abnormal. CAD was considered significant if it was identified at angiography (narrowing >50% ) or if a cardiac event (death or myocardial infarction) occurred during follow-up (mean, 14 months ± 5 [standard deviation]). McNemar test was used to compare the diagnostic accuracy of techniques.

RESULTS

Stress cardiac MR imaging and stress echocardiography had similar specificity, accuracy, and positive and negative predictive values (92% vs 96%, 93% vs 88%, 67% vs 60%, and 100% vs 91%, respectively, for clinical interpretation; 90% vs 92%, 90% vs 88%, 58% vs 56%, and 98% vs 94%, respectively, for blinded interpretation). Stress cardiac MR imaging had higher sensitivity at clinical interpretation (100% vs 38%, P = .025), which did not reach significance at blinded interpretation (88% vs 63%, P = .31). However, multivariable logistic regression analysis showed stress cardiac MR imaging to be the strongest independent predictor of significant CAD (P = .002).

CONCLUSION

In patients presenting to the emergency department with intermediate-risk CP, adenosine stress cardiac MR imaging performed within 12 hours of presentation is safe and potentially has improved performance characteristics compared with stress echocardiography. Online supplemental material is available for this article.

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.

Growth in percutaneous coronary intervention capacity relative to population and disease prevalence

Background

The access to and growth of percutaneous coronary intervention (PCI) has not been fully explored with regard to geographic equity and need. Economic factors and timely access to primary PCI provide the impetus for growth in PCI centers, and this is balanced by volume standards and the benefits of regionalized care.

Methods and Results

Geospatial and statistical analyses were used to model capacity, growth, and access of PCI hospitals relative to population density and myocardial infarction (MI) prevalence at the state level. Longitudinal data were obtained for 2003–2011 from the American Hospital Association, the U.S. Census, and the Centers for Disease Control and Prevention (CDC) with geographical modeling to map PCI locations. The number of PCI centers has grown 21.2% over the last 8 years, with 39% of all hospitals having interventional cardiology capabilities. During the same time, the US population has grown 8.3%, from 217 million to 235 million, and MI prevalence rates have decreased from 4.0% to 3.7%. The most densely concentrated states have a ratio of 8.1 to 12.1 PCI facilities per million of population with significant variability in both MI prevalence and average distance between PCI facilities.

Conclusions

Over the last decade, the growth rate for PCI centers is 1.5× that of the population growth, while MI prevalence is decreasing. This has created geographic imbalances and access barriers with excess PCI centers relative to need in some regions and inadequate access in others.

Multistate implementation of guideline-based cardiac resuscitation systems of care: description of the HeartRescue project

BACKGROUND

There is large and significant regional variation in out-of-hospital cardiac arrest (OHCA), and despite advances in treatment, survival remains low. The American Heart Association has called for the creation of integrated cardiac resuscitation systems of care capable of measuring and improving evidence-based care from bystanders through to hospital discharge.

METHODS

The HeartRescue Project was initiated in 2010 by the Medtronic Foundation in collaboration with 5 academic medical centers and American Medical Response. The HeartRescue Project aims to develop regional cardiac resuscitation systems of care that will implement guideline-based best practice bystander, prehospital, and hospital care with standardized data reporting linked to outcomes. The primary goal is to improve collective OHCA survival by 50% over 5 years.

RESULTS

The total population in the 5 participating states is 41.1 million. At baseline, the HeartRescue Project covers approximately 26.1 million people (63.6%) and has engaged 767 emergency medical services agencies and 269 hospitals. Data will be collected for quality improvement, to inform provider feedback, and serve to define effective strategies to improve cardiac arrest care.

CONCLUSION

The HeartRescue Project is the largest public health initiative of its kind focused entirely on cardiac arrest outcomes. The project is designed to significantly improve OHCA survival by implementing and measuring model systems of care for cardiac resuscitation.

Temporal differences in out-of-hospital cardiac arrest incidence and survival

BACKGROUND

Understanding temporal differences in the incidence and outcomes of out-of-hospital cardiac arrest (OHCA) has important implications for developing preventative strategies and optimizing systems for OHCA care.

METHODS AND RESULTS

We studied 18 588 OHCAs of presumed cardiac origin in patients aged ≥18 years who received resuscitative efforts by emergency medical services (EMS) and were enrolled in the Cardiac Arrest Registry to Enhance Survival (CARES) from October 1, 2005, to December 31, 2010. We evaluated temporal variability in OHCA incidence and survival to hospital discharge. There was significant variability in the frequency of OHCA by hour of the day (P<0.001), day of the week (P<0.001), and month of the year (P<0.001), with the highest incidence occurring during the daytime, from Friday to Monday, in December. Survival to hospital discharge was lowest for OHCA that occurred overnight (from 11:01 pm to 7 am; 7.1%) versus daytime (7:01 am to 3 pm; 10.8%) or evening (3:01 pm to 11 pm; 11.3%; P<0.001) and during the winter (8.8%) versus spring (11.1%), summer (11.0%), or fall (10.0%; P<0.001). There was no difference in survival to hospital discharge between OHCAs that occurred on weekends and weekdays (9.5% versus 10.4%, P=0.06). After multivariable adjustment for age, sex, race, witness status, layperson resuscitation, first monitored cardiac rhythm, and emergency medical services response time, compared with daytime and spring, survival to hospital discharge remained lowest for OHCA that occurred overnight (odds ratio, 0.81; 95% confidence interval, 0.70-0.95; P=0.008) and during the winter (odds ratio, 0.81; 95% confidence interval, 0.70-0.94; P=0.006), respectively.

CONCLUSIONS

There is significant temporal variability in the incidence of and survival after OHCA. The relative contribution of patient pathophysiology, likelihood of the OHCA being observed, and prehospital and hospital-based resuscitative factors deserves further exploration.

Bypassing the Emergency Department and Time to Reperfusion in Patients With Prehospital ST-Segment–Elevation

Background—

Among patients identified prehospital with ST-segment–elevation myocardial infarction, emergency medical service transport from the field directly to the catheterization laboratory, thereby bypassing the emergency department (ED), may shorten time to reperfusion.

Methods and Results—

We studied 1687 patients identified prehospital with ST-segment–elevation myocardial infarction from the Reperfusion in Acute Myocardial Infarction in Carolina Emergency Departments (RACE) project, transported via emergency medical service directly to 21 North Carolina hospitals for primary percutaneous coronary intervention between July 2008 and December 2009. Treatment time intervals were compared between patients evaluated in the ED (ED evaluation) and those transported directly to the catheterization laboratory (ED bypass). Emergency medical service transported 1401 (83.0%) patients to the ED, whereas the ED was bypassed for 286 (17.0%) patients. Overall, first medical contact to device activation within 90 minutes was achieved in 913 (54.1%) patients. Among patients evaluated in the ED, median time (25th–75th percentiles) from ED arrival to catheterization laboratory arrival was 30 (20–41) minutes. First medical contact to device activation occurred faster (75 [59–93] versus 90 [76–109] minutes; P <0.001) and was more frequently achieved within 90 minutes (74.1% versus 50.1%; P <0.001) among ED bypass patients.

Conclusions—

Among patients identified prehospital with ST-segment–elevation myocardial infarction and transported directly to a percutaneous coronary intervention hospital, only 1 in 2 achieve device activation within 90 minutes. A median of 30 minutes is spent in the ED, contributing significantly to the failure to achieve timely reperfusion. The strategy to bypass the ED is used infrequently and represents a potential opportunity to improve reperfusion times.