CLINICAL RESEARCH: MYOCARDIAL INFARCTION
Utilization and Impact of Pre-Hospital Electrocardiograms for Patients With Acute ST-Segment Elevation Myocardial InfarctionData From the NCDR (National Cardiovascular Data Registry) ACTION (Acute Coronary Treatment and Intervention Outcomes Network) Registry
Deborah B. Diercks, MD, MSc*,*,
Michael C. Kontos, MD ,
Anita Y. Chen, MS ,
Charles V. Pollack, Jr, MD, MS ,
Stephen D. Wiviott, MD||,
John S. Rumsfeld, MD, PhD¶,
David J. Magid, MD, MPH¶,
W. Brian Gibler, MD#,
Christopher P. Cannon, MD**,
Eric D. Peterson, MD, MPH,
Matthew T. Roe, MD, MHS on behalf of the NCDR ACTION Registry Participants
* University of California Davis Medical Center, Sacramento, California
Virginia Commonwealth University Health System, Richmond, Virginia
Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina
Pennsylvania Hospital, Philadelphia, Pennsylvania
|| Brigham and Women's Hospital, Boston, Massachusetts
¶ University of Colorado Medical Center, Denver, Colorado
# University of Cincinnati Hospital, Cincinnati, Ohio
** TIMI Study Group, Brigham and Women's Hospital, Boston, Massachusetts
Manuscript received July 11, 2008;
revised manuscript received September 10, 2008,
accepted September 15, 2008.
* Reprint requests and correspondence: Dr. Deborah B. Diercks, Department of Emergency Medicine, University of California, Davis Medical Center, 2315 Stockton Boulevard, PSSB 2100, Sacramento, California 95661 (Email: dbdiercks{at}ucdavis.edu).
 |
Abstract
|
|---|
Objectives: This study sought to determine the association of pre-hospital electrocardiograms (ECGs) and the timing of reperfusion therapy for patients with ST-segment elevation myocardial infarction (STEMI).
Background: Pre-hospital ECGs have been recommended in the management of patients with chest pain transported by emergency medical services (EMS).
Methods: We evaluated patients with STEMI from the NCDR (National Cardiovascular Data Registry) ACTION (Acute Coronary Treatment and Intervention Outcomes Network) registry who were transported by EMS from January 1, 2007, through December 31, 2007. Patients were stratified by the use of pre-hospital ECGs, and timing of reperfusion therapy was compared between the 2 groups.
Results: A total of 7,098 of 12,097 patients (58.7%) utilized EMS, and 1,941 of these 7,098 EMS transport patients (27.4%) received a pre-hospital ECG. Among the EMS transport population, primary percutaneous coronary intervention was performed in 92.1% of patients with a pre-hospital ECG versus 86.3% with an in-hospital ECG, whereas fibrinolytic therapy was used in 4.6% versus 4.2% of patients. Median door-to-needle times for patients receiving fibrinolytic therapy (19 min vs. 29 min, p = 0.003) and median door-to-balloon times for patients undergoing primary percutaneous coronary intervention (61 min vs. 75 min, p < 0.0001) were significantly shorter for patients with a pre-hospital ECG. A suggestive trend for a lower risk of in-hospital mortality was observed with pre-hospital ECG use (adjusted odds ratio: 0.80, 95% confidence interval: 0.63 to 1.01).
Conclusions: Only one-quarter of these patients transported by EMS receive a pre-hospital ECG. The use of a pre-hospital ECG was associated with a greater use of reperfusion therapy, faster reperfusion times, and a suggested trend for a lower risk of mortality.
Key Words: myocardial infarction • pre-hospital electrocardiogram • reperfusion
|
Abbreviations and Acronyms
| | CHF = congestive heart failure | | DTB = door-to-balloon time | | DTN = door-to-needle time | | ECG = electrocardiogram | | EMS = emergency medical services | | IQR = interquartile range | | PCI = percutaneous coronary intervention | | STEMI = ST-segment elevation myocardial infarction |
|
The American College of Cardiology/American Heart Association ST-segment elevation myocardial infarction (STEMI) guidelines recommend prompt reperfusion with fibrinolytic agents within 30 min of hospital arrival (door-to-needle time [DTN]) or primary percutaneous coronary intervention (PCI) within 90 min of arrival (door-to-balloon time [DTB]) (1). However, contemporary analyses show that the majority of hospitals in the U.S. do not meet these benchmarks for the timing reperfusion therapy (2). A recent consensus statement endorsed the use of pre-hospital electrocardiograms (ECGs) to rapidly diagnose and triage patients transported by emergency medical services (EMS) with a suspected STEMI before hospital arrival (3). Regional or municipal studies performed within the last few years have shown that the use of pre-hospital ECGs was associated with shorter reperfusion times, and nationwide efforts have recently been developed to increase the availability of pre-hospital ECGs across the U.S. (4–7). We therefore analyzed data from the NCDR (National Cardiovascular Data Registry) ACTION (Acute Coronary Treatment and Intervention Outcomes Network) registry to evaluate the nationwide utilization and impact of pre-hospital ECGs in a large cohort of patients with STEMI.
|
Methods
|
|---|
The NCDR ACTION registry and quality improvement program began January 1, 2007. As applicable at each site, data collected for this registry were either approved by an institutional review board or considered quality assurance data, and not subject to institutional review board approval.
Patient inclusion criteria.
Between January 1, 2007, and December 31, 2007, 271 ACTION hospitals enrolled 19,481 patients with STEMI (defined as persistent ST-segment elevation or new left bundle branch block and presenting within 24 h of ischemic symptom onset). We excluded the following patients: those not evaluated first in the emergency department or the cardiac catheterization laboratory (n = 2,575); patients transferred to an ACTION-participating hospital because the structure of the data collection form prevented delineation of location of the first ECG obtained (pre-hospital vs. in the outside hospital emergency department) (n = 4,568); those with missing information on EMS transport (n = 79); those with missing data on pre-hospital ECG (n = 69); and those not listed as being transported by EMS, but who had a pre-hospital ECG recorded (n = 93). The total initial analysis sample thus consisted of 12,097 patients with STEMI who directly presented to ACTION-participating hospitals either by self-transport or EMS transport.
Data collection and accuracy.
Data were abstracted by a trained data collector at each hospital. Variables collected included pre-hospital data, medical history, treatments administered, as well as associated major contraindications to evidence-based therapies, and in-hospital outcomes.
Statistical analyses.
Patients were initially categorized by whether or not they were transported by EMS. An in-depth comparison was made among those patients with and without a pre-hospital ECG, after restricting the analysis cohort to only those transported by EMS.
Demographic and clinical characteristics, reperfusion strategies, treatment patterns, and in-hospital outcomes were compared between patients with and without a pre-hospital ECG. Median values with interquartile ranges (IQRs) (25th, 75th percentile) were used to describe continuous variables, and numbers (percentages) were used for categorical variables. Patients were additionally classified regarding presenting during "on hours" (7 AM to 7 PM, Monday through Friday) or "off hours" (all other time periods), and by the time to the in-hospital ECG  10 or >10 min. To test for independence, pre-hospital ECG and baseline characteristics, in-hospital care patterns and outcomes, and the continuous and ordinal categorical variables were compared using stratum-adjusted Wilcoxon rank-sum tests, whereas nominal categorical variables were compared using stratum adjusted chi-square tests, for which stratification is by hospital.
We evaluated 2 process-of-care measures: time from door to reperfusion treatment with either fibrinolytic agents or primary PCI. In examining the association between pre-hospital ECG and time to reperfusion, we used the generalized estimating equations method to account for within-hospital clustering. Variables entered into the model are based on known clinical predictors of outcome. Furthermore, the relationship between in-hospital outcomes and pre-hospital ECG was explored using the logistic generalized estimating equations method adjusting for patient baseline characteristics only. Because DTB and DTN times were skewed, a log-transformation of these times was applied to normalize the distribution. When a dependent variable of a regression analysis has been transformed, the estimated coefficients must also be transformed to be interpreted appropriately (8). All analyses were performed using SAS software (version 9.1, SAS Institute, Cary, North Carolina).
|
Results
|
|---|
Clinical characteristics and treatment.
A total of 7,098 of 12,097 patients (58.7%) included were transported to the ACTION-participating hospital by EMS. Patients transported by EMS were older; were less commonly male; more commonly had prior myocardial infarction (MI), prior congestive heart failure (CHF), and signs of CHF on presentation; and had shorter times from symptom onset to hospital presentation compared with patients who were self-transported to the ACTION-participating hospital (Table 1). Among the 7,098 patients transported by EMS, 1,941 (24.7%) received a pre-hospital ECG. Patients with a pre-hospital ECG were more commonly male, and less commonly had diabetes and left bundle branch block or signs of CHF on presentation compared with patients with an in-hospital ECG. The time from symptom onset to hospital presentation was similar between the groups (Table 2).
Use of reperfusion therapy and acute medications by pre-hospital ECG use.
Patients with a pre-hospital ECG were more likely to undergo primary PCI and less likely to receive no reperfusion therapy compared with patients with an in-hospital ECG (Table 3). Patients with a pre-hospital ECG were more likely to receive aspirin, clopidogrel, and glycoprotein IIb/IIIa inhibitors within the first 24 h (Table 4).
Timing of reperfusion therapy.
Among patients receiving reperfusion therapy, DTN and DTB times were faster in those with a pre-hospital ECG (Table 5). This difference persisted when stratified analysis were performed by "off-hours" versus "on-hours" presentation and by time to the in-hospital ECG (10 min or not). These differences in DTN and DTB times persisted after adjusting for confounders. Patients who had a pre-hospital ECG had faster DTN times (adjusted decrease of 24.9%, 95% confidence interval: –38.1% to –9.0%) and faster DTB times (adjusted decrease of 19.3%, 95% confidence interval: –23.3% to –15.2%) compared with patients with an in-hospital ECG.
In-hospital clinical outcomes.
Among the overall EMS transport population, pre-hospital ECG use was associated with a trend toward a reduced risk of adjusted in-hospital mortality, CHF, and shock (Table 6). Among patients who received any reperfusion therapy, there was no difference in the adjusted risk of mortality by pre-hospital ECG use.
|
Discussion
|
|---|
On a national level, there has been increased interest in the U.S. in the development of STEMI systems of care to develop integrated reperfusion approaches based on local and regional EMS and hospital capabilities. The utilization of pre-hospital ECGs by EMS providers is a key component in the development of STEMI systems of care and reducing reperfusion times, because pre-hospital identification of STEMI patients allows for direct transport of patients to the nearest hospital with primary PCI capabilities as well as early activation of the cardiac catheterization laboratory before the patient arrives at the receiving hospital (3). However, broad adoption of pre-hospital ECGs has not yet occurred in the U.S. as we have shown that fewer than 20% of patients transported by EMS had a pre-hospital ECG performed (7,9). However, practical factors that may have limited the use of pre-hospital ECGs in the U.S., such as the cost of capital equipment purchases for local EMS services, challenges of training of EMS providers in ECG interpretation, and technical limitations regarding transmission of pre-hospital ECG findings to hospitals for physician over-read, will need to be addressed to stimulate more widespread adoption of this technology.
Study limitations.
This study has several potential limitations. First, there likely were unmeasured differences in the clinical presentation of patients for whom a pre-hospital ECG was used. Second, we did not collect information on how the pre-hospital ECGs were interpreted (EMS provider interpretation vs. wireless transmission for physician over-read), whether and how the results were transmitted to the ACTION hospital before the patient's arrival, how the pre-hospital ECG impacted catheterization laboratory activation, and whether patients were diverted from a community hospital to a tertiary hospital participating in the ACTION registry based on the pre-hospital ECG results. Third, we cannot comment on the specificity or sensitivity of pre-hospital ECGs for accurately identifying STEMI patients because there was no central core laboratory interpretation of the ECGs and information was not collected regarding the accuracy of the EMS providers' interpretation of the pre-hospital ECGs. Fourth, because patients with a pre-hospital ECG were younger and had fewer comorbidities compared with patients with an in-hospital ECG, the use of pre-hospital ECGs may have been preferentially directed toward patients with a more straightforward presentation and ischemic symptoms that triggered use of pre-hospital ECG. The lower use of reperfusion therapy in the in-hospital ECG group may support this observation. Finally, we excluded a significant proportion of patients, including those who did not present first to the emergency department or cardiac catheterization laboratory, so the impact of pre-hospital ECGs may not have been completely assessed.
|
Conclusions
|
|---|
Among a contemporary population of STEMI patients in the U.S. transported by EMS, one-quarter received a pre-hospital ECG. Pre-hospital ECG use was associated with a greater use of reperfusion therapy, faster reperfusion times with both fibrinolytic agents and primary PCI, and a trend for a lower adjusted risk of in-hospital mortality. These data provide contemporary evidence supporting a more widespread use of pre-hospital ECGs as a key triage tool for patients with ischemic symptoms and suspected STEMI who are first evaluated by EMS.
|
References
|
|---|
1. Antman EM, Hand M, Armstrong PW, et al. 2007 focused update of the ACC/AHA 2004 guidelines for the management of patients with ST-elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (2007 Writing Group to Review New Evidence and Update the ACC/AHA 2004 Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction) J Am Coll Cardiol 2008;51:210-247.[Free Full Text]2. Nallamothu BK, Bates ER, Herrin J, Wang Y, Bradley EH, Krumholz HM. Times to treatment in transfer patients undergoing primary percutaneous coronary intervention in the United States: National Registry of Myocardial Infarction (NRMI)-3/4 analysis Circulation 2005;111:761-767.[Abstract/Free Full Text] 3. Ting HH, Krumholz HM, Bradley EH, et al. Implementation and integration of prehospital ECGs into systems of care for acute coronary syndrome. A scientific statement from the American Heart Association Interdisciplinary Council on Quality of Care and Outcomes Research, Emergency Cardiovascular Care Committee, Council on Cardiovascular Nursing, and Council on Clinical Cardiology. Circulation 2008;118:1066-1079.[Free Full Text] 4. Le May MR, So DY, Dionne R, et al. A citywide protocol for primary PCI in ST-segment elevation myocardial infarction N Engl J Med 2008;358:231-240.[CrossRef][Web of Science][Medline] 5. Dhruva VN, Abdelhadi SI, Anis A, et al. ST-Segment Analysis Using Wireless Technology in Acute Myocardial Infarction (STAT-MI) trial J Am Coll Cardiol 2007;50:509-513.[Abstract/Free Full Text] 6. Amit G, Cafri C, Gilutz H, Ilia R, Zahger D. Benefit of direct ambulance to coronary care unit admission of acute myocardial infarction patients undergoing primary percutaneous intervention Int J Cardiol 2007;119:355-358.[CrossRef][Medline] 7. Afolabi BA, Novaro GM, Pinski SL, Fromkin KR, Bush HS. Use of the prehospital ECG improves door-to-balloon times in ST segment elevation myocardial infarction irrespective of time of day or day of week Emerg Med J 2007;24:588-591.[Abstract/Free Full Text] 8. Zhou X, Stroupe KT, Tierney WM. Regression analysis of health care charges with heteroscedasticity J R Stat Soc C (Appl Stat) 2001;50:303-312. 9. Bradley EH, Roumanis SA, Radford MJ, et al. Achieving door-to-balloon times that meet quality guidelines: how do successful hospitals do it? J Am Coll Cardiol 2005;46:1236-1241.[Abstract/Free Full Text]
Related Article
-
Inside This Issue of JACC
J. Am. Coll. Cardiol. 2009 53: A24.
[Full Text]
[PDF]
This article has been cited by other articles:
|
|
|
|
 
J. L. Garvey, L. Monk, C. B. Granger, J. R. Studnek, M. L. Roettig, C. C. Corbett, and J. G. Jollis
Rates of Cardiac Catheterization Cancelation for ST-Segment Elevation Myocardial Infarction After Activation by Emergency Medical Services or Emergency Physicians: Results From the North Carolina Catheterization Laboratory Activation Registry
Circulation,
January 17, 2012;
125(2):
308 - 313.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. A. Mixon, E. Suhr, G. Caldwell, R. D. Greenberg, F. Colato, J. Blackwell, C.-H. Jo, and G. J. Dehmer
Retrospective Description and Analysis of Consecutive Catheterization Laboratory ST-Segment Elevation Myocardial Infarction Activations With Proposal, Rationale, and Use of a New Classification Scheme
Circ Cardiovasc Qual Outcomes,
January 1, 2012;
5(1):
62 - 69.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
D. M. Nestler, R. D. White, C. S. Rihal, L. A. Myers, C. M. Bjerke, R. J. Lennon, J. L. Schultz, M. R. Bell, B. J. Gersh, D. R. Holmes Jr, et al.
Impact of Prehospital Electrocardiogram Protocol and Immediate Catheterization Team Activation for Patients With ST-Elevation-Myocardial Infarction
Circ Cardiovasc Qual Outcomes,
November 1, 2011;
4(6):
640 - 646.
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. P. Vavalle and C. B. Granger
The Need for Regional Integrated Care for ST-Segment Elevation Myocardial Infarction
Circulation,
August 16, 2011;
124(7):
851 - 856.
[Full Text]
[PDF]
|
|
|
|
|
|
|
R. Mathews, E. D. Peterson, S. Li, M. T. Roe, S. W. Glickman, S. D. Wiviott, J. F. Saucedo, E. M. Antman, A. K. Jacobs, and T. Y. Wang
Use of Emergency Medical Service Transport Among Patients With ST-Segment-Elevation Myocardial Infarction: Findings From the National Cardiovascular Data Registry Acute Coronary Treatment Intervention Outcomes Network Registry-Get With the Guidelines
Circulation,
July 12, 2011;
124(2):
154 - 163.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. W. Glickman, B. L. Lytle, F.-S. Ou, G. Mears, S. O'Brien, C. B. Cairns, J. L. Garvey, D. J. Bohle, E. D. Peterson, J. G. Jollis, et al.
Care Processes Associated With Quicker Door-In-Door-Out Times for Patients With ST-Elevation-Myocardial Infarction Requiring Transfer: Results From a Statewide Regionalization Program
Circ Cardiovasc Qual Outcomes,
July 1, 2011;
4(4):
382 - 388.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. Martinoni, S. D. Servi, E. Boschetti, R. Zanini, T. Palmerini, A. Politi, G. Musumeci, G. Belli, M. D. Paolis, F. Ettori, et al.
Importance and limits of pre-hospital electrocardiogram in patients with ST elevation myocardial infarction undergoing percutaneous coronary angioplasty
European Journal of Cardiovascular Prevention & Rehabilitation,
June 1, 2011;
18(3):
526 - 532.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Sanchez-Ross, G. Oghlakian, J. Maher, B. Patel, V. Mazza, D. Hom, V. Dhruva, D. Langley, J. Palmaro, S. Ahmed, et al.
The STAT-MI (ST-Segment Analysis Using Wireless Technology in Acute Myocardial Infarction) Trial Improves Outcomes
J. Am. Coll. Cardiol. Intv.,
February 1, 2011;
4(2):
222 - 227.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. Huber, K. A. A. Fox, P. Goldstein, and N. Danchin
Chapter 40 Systems of care for patients with acute coronary syndrome
The ESC Textbook of Acute and Intensive Cardiac Care,
December 1, 2010;
1(1):
med-9780199584314-chapter - med-9780199584314-chapter.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. R. Studnek, L. Garvey, T. Blackwell, S. Vandeventer, and S. R. Ward
Association Between Prehospital Time Intervals and ST-Elevation Myocardial Infarction System Performance
Circulation,
October 12, 2010;
122(15):
1464 - 1469.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. G. Jollis
Moving Care Forward: Prehospital Emergency Cardiac Systems
Circulation,
October 12, 2010;
122(15):
1443 - 1445.
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. W. Glickman, C. B. Granger, F.-S. Ou, S. O'Brien, B. L. Lytle, C. B. Cairns, G. Mears, J. W. Hoekstra, J. L. Garvey, E. D. Peterson, et al.
Impact of a Statewide ST-Segment-Elevation Myocardial Infarction Regionalization Program on Treatment Times for Women, Minorities, and the Elderly
Circ Cardiovasc Qual Outcomes,
September 1, 2010;
3(5):
514 - 521.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. W. Baran, K. A. Kamrowski, J. J. Westwater, V. H. Tschida, C. F. Alexander, M. M. Beahrs, T. A. Biggs, P. T. Koller, B. D. Mahoney, S. T. Murray, et al.
Very Rapid Treatment of ST-Segment-Elevation Myocardial Infarction: Utilizing Prehospital Electrocardiograms to Bypass the Emergency Department
Circ Cardiovasc Qual Outcomes,
July 1, 2010;
3(4):
431 - 437.
[Full Text]
[PDF]
|
|
|
|
|
|
|
H.-J. Dieker, S. S. B. Liem, H. El Aidi, P. van Grunsven, W. R. M. Aengevaeren, M. A. Brouwer, and F. W. A. Verheugt
Pre-Hospital Triage for Primary Angioplasty: Direct Referral to the Intervention Center Versus Interhospital Transport
J. Am. Coll. Cardiol. Intv.,
July 1, 2010;
3(7):
705 - 711.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
D. H. Daudelin, A. J. Sayah, M. Kwong, M. C. Restuccia, W. A. Porcaro, R. Ruthazer, J. D. Goetz, W. M. Lane, J. R. Beshansky, and H. P. Selker
Improving Use of Prehospital 12-Lead ECG for Early Identification and Treatment of Acute Coronary Syndrome and ST-Elevation Myocardial Infarction
Circ Cardiovasc Qual Outcomes,
May 1, 2010;
3(3):
316 - 323.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. R. Pitta, L. A. Myers, C. M. Bjerke, R. D. White, and H. H. Ting
Using Prehospital Electrocardiograms to Improve Door-to-Balloon Time for Transferred Patients With ST-Elevation Myocardial Infarction: A Case of Extreme Performance
Circ Cardiovasc Qual Outcomes,
January 1, 2010;
3(1):
93 - 97.
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. H. Pedersen, S. Galatius, P. R. Hansen, R. Mogelvang, S. Z. Abildstrom, R. Sorensen, U. Davidsen, A. Galloe, U. Abildgaard, A. Iversen, et al.
Field Triage Reduces Treatment Delay and Improves Long-Term Clinical Outcome in Patients With Acute ST-Segment Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention
J. Am. Coll. Cardiol.,
December 8, 2009;
54(24):
2296 - 2302.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
Top
Abstract
Methods