Cardiac Catheterization Laboratory Activation Research Articles

The appropriateness of single page of activation of the cardiac catheterization laboratory by emergency physician for patients with suspected ST-segment elevation myocardial infarction: a cohort study

BackgroundThe early use of reperfusion therapy has a significant effect on the prognosis of patients with ST-segment elevation myocardial infarction (STEMI), and it is recommended that emergency department (ED) physicians activate the cardiac catheterization laboratory (CCL) as soon as possible to treat these patients. The aim of this study was to examine the appropriateness of emergency physician activation of the CCL for patients with suspected STEMI. Inappropriate activations (i.e., false positive activations) were identified according to a variety of criteria.MethodsAll patients with emergency physician CCL activations between August 2009 and April 2011 were included in the study. False positive cases were defined according to ECG criteria and cardiologists' reviews of patients' initial clinical information.ResultsED physicians used a STEMI page to activate the CCL 117 times. According to reviews by cardiologists, this activation was appropriate 89.8% of the time (in 105/117 cases). Truly unnecessary activation (i.e., cases in which STEMI was not identified by the cardiologists, no clear culprit coronary artery was present, no significant coronary artery disease and cardiac biomarkers were negative) occurred 5.1% of the time (in 6/117 cases).ConclusionsCCL activation was appropriate for most patients and was unnecessary in a relatively small percentage of cases. This result supports the current recommendation for CCL activation by emergency physicians. Such early activation is a key strategy in the reduction of door-to-balloon time.

Primary Percutaneous Coronary Intervention for Patients Presenting With ST-Elevation Myocardial Infarction: Process Improvements in Rural Prehospital Care Delivered by Emergency Medical Services

Background Safe and effective patient care for ST-elevation myocardial infarction (STEMI) relies on prompt emergency medical service (EMS) and established care coordination with receiving hospitals to conduct primary percutaneous coronary intervention (PCI). Likewise, a new emphasis has been placed on first medical contact-to-balloon (E2B) times as opposed to door-to-balloon times, identifying prehospital care as an important contributing factor for high-quality STEMI care. Therefore, we evaluated EMS processes of care before and after a period of continuous quality improvement to improve E2B times in our rural tertiary care medical center. Methods A retrospective, consecutive cohort study was conducted on 177 patients who received primary PCI at Dartmouth-Hitchcock Medical Center, a rural hospital, from January 1, 2006 to October 31, 2009. This cohort was stratified from January 1, 2008 to May 1, 2008 (n = 88) and May 1, 2008 to October 31, 2009 (n = 89), to acknowledge periods of no improvement (pre) and continuous quality improvement (post) in STEMI care. Primary outcome measures included frequency of non–PCI-capable hospital bypass, E2B, and frequency of prehospital electrocardiogram (ECG) and cardiac catheterization laboratory (CCL) activation. Descriptive statistics and log-rank tests were used to determine whether measures differed significantly by time period. A time-to-event analysis was conducted using a Cox proportional hazards model to assess the impact of outcomes measures on E2B pre/post–May 1, 2008. Results Patients who presented before May 1, 2008 had longer E2B times compared with patients in the post–May 1, 2008 cohort (145.1 minutes vs 115.2 minutes, t test P = .01). A log-rank test confirmed this (pre: 130 minutes vs post: 106 minutes, χ 2 = 5.3, log-rank P = .02). Similarly, patients who presented before May 1, 2008 had lower percentages of prehospital ECGs (49% vs 80%, P = .001) and CCL activations (4% vs 32%, P < .001). When prehospital ECGs (140 minutes vs 106 minutes, χ 2 = 5.9, log-rank P = .01) or CCL activations (125 minutes vs 98 minutes, χ 2 = 4.2, log-rank P = .04) were conducted, E2B times were significantly reduced. Patients who received both prehospital ECGs and prehospital CCL activations had significantly reduced E2B times compared with those who did not (125 minutes vs 91 minutes, χ 2 = 4.8, P = .02). Conclusions The time saving benefits of prehospital ECGs may not be fully realized unless prehospital CCL activations also occur. EMS providers achieved further reductions in median E2B of approximately 24 minutes when prehospital ECGs were combined with prehospital CCL activation. Every effort should be made by PCI-capable medical centers to assess prehospital STEMI care and to integrate EMS providers into regional STEMI care quality improvement initiatives and education.

The impact of prehospital activation of the cardiac catheterization team on time to treatment for patients presenting with ST-segment-elevation myocardial infarction

Objective We sought to evaluate the accuracy of emergency medical services (EMS) activation of the cardiac catheterization laboratory (CCL) for patients with ST-elevation myocardial infarction (STEMI) and its impact on treatment intervals from dispatch to reperfusion. Methods We conducted a before-and-after cohort study of patients presenting via EMS with prehospital electrocardiogram findings consistent with STEMI. Before August 20, 2007, percutaneous coronary intervention was initiated after patient arrival. Afterward, EMS providers could activate the CCL if the prehospital electrocardiogram automated interpretation indicated STEMI. All interval times from EMS dispatch to percutaneous coronary intervention were measured via synchronized timepieces. Results A total of 53 patients, 14 before and 39 after prehospital activation, were included. Emergency medical services CCL activation was 79.6% sensitive (95% confidence interval [CI], 65.2%-89.3%) and 99.7% specific (95% CI, 99.1%-99.9%). Mean door-to-hospital electrocardiogram and mean CCL-to-reperfusion times were unaffected by the intervention. Prehospital activation of the CCL significantly improved mean door-to-balloon (D2B) time by 18.2 minutes (95% CI, 7.69-28.71 minutes; P = .0029) and door-to-CCL by 14.8 minutes (95% CI, 6.20-23.39 minutes; P = .0024). Improvements in D2B were independent of presentation during peak hours (F ratio = 17.02, P < .0001). There were significant time savings reflected in all EMS intervals: 20.7 minutes (95% CI, 9.1-32.3 minutes; P = .0015) in mean dispatch-to-reperfusion time, 22.2 minutes (95% CI, 11.45-32.95 minutes; P = .0003) in mean first medical contact-to-reperfusion time, and 20 minutes (95% CI, 10.95-29.05 minutes; P = .0001) in recognition-to-reperfusion time. Conclusions Emergency medical service providers can appropriately activate the CCL for patients with STEMI before emergency department arrival, significantly reducing mean D2B time. Significant reduction is demonstrated throughout EMS intervals.

Emergency physician–initiated cath lab activation reduces door to balloon times in ST-segment elevation myocardial infarction patients

Objectives We evaluated the impact of emergency physician (EP)–initiated primary percutaneous coronary intervention (PCI) via a single-group page on door to balloon (D2B) interval times in patients with ST-segment elevation myocardial infarction. Methods Consecutive ST-segment elevation myocardial infarction patients presenting to the emergency department between February 2004 and September 2008 were divided into 4 groups: group 1, PCI performed on an ad hoc basis after cardiology consultation; group 2, primary PCI activated via a single-group page only on-call cardiology consultation; group 3, primary PCI with EP cardiac catheterization laboratory (CCL) activation via the same page strategy; group 4, prehospital CCL activation based on prehospital diagnostic electrocardiogram. Composite D2B and relevant time intervals were measured for each time group. Results A total of 295 consecutive patients undergoing emergent angiography were included. Times decreased for most time intervals from groups 1 to 4. Although there was no significant change in composite D2B or any measured interval time with the introduction of PCI after emergent cardiology consultation, each decreased significantly after implementing an EP-initiated PCI strategy except CCL2B (D2B 95 to 77 minutes, D2E 14 to 10 minutes, D2CCL 71 to 50 minutes). Further significant reductions in D2B time were achieved among all patients after the institution of emergency medicine services activation of the CCL (D2B 77 to 64 minutes, D2CCL 50 to 38 minutes, CCL2B 28 to 22 minutes). Conclusions A systematic process of initiating D2B recommendations, including EP-initiated CCL activation via a single-group page, significantly reduces D2CCL and D2B times.

Early Cardiac Catheterization Laboratory Activation by Paramedics for Patients with ST-segment Elevation Myocardial Infarction on Prehospital 12-Lead Electrocardiograms

Background. Prompt reperfusion in ST-segment elevation myocardial infarction (STEMI) saves lives. Although studies have shown that paramedics can reliably interpret STEMI on prehospital 12-lead electrocardiograms (p12ECGs), prehospital activation of the cardiac catheterization laboratory by emergency medical services (EMS) has not yet gained widespread acceptance. Objective. To quantify the potential reduction in time to percutaneous coronary intervention (PCI) by early prehospital activation of the cardiac catheterization laboratory in STEMI. Methods. This prospective, observational study enrolled all patients diagnosed with STEMI by paramedics in a mid-sized regional EMS system. Patients were enrolled if: 1) the paramedic interpreted STEMI on the p12ECG, 2) the Acute Cardiac Ischemia Time-Insensitive Predictive Instrument (ACI-TIPI) score was 75%% or greater, and 3) the patient was transported to either of two area PCI centers. Data recorded included the time of initial EMS “STEMI alert” from the scene, time of arrival at the emergency department (ED), and time of actual catheterization laboratory activation by the ED physician, all using synchronized clocks. The primary outcome measure was the time difference between the STEMI alert and the actual activation (i.e., potential time savings). The false-positive rate (patients incorrectly diagnosed with STEMI by paramedics) was also calculated and compared with a locally accepted false-positive rate of 10%%. Results. Twelve patients were enrolled prior to early termination of the study. The mean and median potential time reductions were 15 and 11 minutes, respectively (range 7–29 minutes). There was one false STEMI alert (8.3%% false-positive rate) for a patient with a right bundle branch block who subsequently had a non–ST-segment elevation myocardial infarction. The study was terminated when our cardiologists adopted a prehospital catheterization laboratory activation protocol based on our initial data. Conclusion. Important reductions in time to reperfusion seem possible by activation of the catheterization laboratory by EMS from the scene, with an acceptably low false-positive rate in this small sample. This type of clinical research can inform multidisciplinary policies and bring about meaningful clinical practice changes.

Abstract 4863: Emergency Cardiac Catheterization for “False-Positive” ST-Segment Elevation Myocardial Infarction

Introduction : In a push to treat STEMI patients with primary PCI within 90 minutes of door-to-balloon time, medical institutions have developed emergency cardiac catheterization laboratory activation protocols that bypass other routine clinical assessments. This has raised concerns about more frequent catheterizations in patients who may not need them. Our study objective was to determine the incidence, predictors and prognosis of false-positive STEMI. Methods : We studied a prospective cohort of patients diagnosed with STEMI who received emergency cardiac catheterization with intention of primary PCI between January 2005 and December 2007 at a tertiary care center serving more than 20 community hospitals. False-positive STEMI was defined as absence of a clear culprit lesion on coronary angiography. Multivariate logistic regression was used to identify independent predictors of false-positive STEMI. Results : Of 489 patients who received emergency cardiac catheterization indicated for STEMI, 54 (11.0%, 95% CI 8.3%–13.8%) had no culprit lesion on coronary angiography. Independent predictors of false-positive STEMI identified on multivariate analysis are shown in the table . Among patients with false-positive STEMI, 22.2% had a serious cardiac diagnosis by catheterization. One-year incidence of acute myocardial infarction or PCI was 7.5% in patients with a culprit lesion vs. 1.9% in patients with no culprit lesion (p=0.08). One-year mortality was 6.5% among patients with a culprit lesion vs. 3.7% without (p=0.22). Conclusion : False-positive STEMI is common among patients undergoing emergency cardiac catheterization. A better understanding of the identifiers for false-positive STEMI may help physicians quickly reassess the utility of emergency cardiac catheterization when the diagnosis of STEMI is in doubt. Independent Predictors of False-Positive ST-Segment Elevation Myocardial Infarction From Multivariate Analysis

“False-positive” cardiac catheterization laboratory activation among patients with suspected ST-segment elevation myocardial infarction

“False-positive” cardiac catheterization laboratory activation among patients with suspected ST-segment elevation myocardial infarction

An Evaluation of the Accuracy of Emergency Physician Activation of the Cardiac Catheterization Laboratory for Patients With Suspected ST-Segment Elevation Myocardial Infarction

Current recommendations indicate that emergency physicians should activate cardiac catheterization laboratory personnel by a single page for ST-segment elevation myocardial infarction (STEMI) patients. We assessed the accuracy of emergency physician cardiac catheterization laboratory activations, angiographic findings, outcomes, and treatment times among patients with and without STEMI. We classified the appropriateness and outcomes of consecutive emergency physician STEMI pages between June 2006 and September 2008. Emergency physician activations of the cardiac catheterization laboratory were classified according to the findings of the initial ECG compared with cardiology interpretation for the presence of STEMI and presence of coronary disease. During a 27-month period, emergency physician activation of the cardiac catheterization laboratory occurred 249 times. There were 188 (76%) patients with a true STEMI, of whom 13 did not receive emergency angiography. Of the 37 (15%) patients who had ECG findings meeting STEMI criteria and who ultimately did not have myocardial necrosis and underwent emergency angiography, 12 had significant disease and 5 had revascularization performed. Eleven patients had ECGs concerning for but not meeting STEMI criteria; all had emergency angiography (n=11) or received a diagnosis of non-STEMI (n=6). Only 13 patients were considered as having received unnecessary cardiac catheterization laboratory activations (5.2%) in which emergency angiography was not performed and myocardial infarction was excluded. A significant number of emergency physician STEMI cardiac catheterization laboratory activations are for patients who did not meet standard STEMI criteria. However, most had ECG findings and symptoms that lead to emergency angiography, had significant disease, or were diagnosed with non-STEMI. Only a small percentage of patients received unnecessary cardiac catheterization laboratory activations. Our findings support current recommendations for emergency physician cardiac catheterization laboratory activation for potential STEMI patients.

Can Paramedics Read ST-segment Elevation Myocardial Infarction on Prehospital 12-Lead Electrocardiograms?

Introduction. Activation of the cardiac catheterization laboratory prior to patient arrival at the hospital, based on a prehospital 12-lead electrocardiogram (ECG), reduces door-to-balloon time by 10–55 minutes for patients with ST-segment elevation myocardial infarction (STEMI). In emergency medical services (EMS) systems where transmission of the ECG to the emergency department (ED) is not feasible, the ability of paramedics to accurately read 12-lead ECGs is crucial to the success of a prehospital catheterization laboratory activation program. Objective. To determine whether paramedics can accurately diagnose STEMI on a prehospital 12-lead ECG anddecide to activate the cardiac catheterization laboratory appropriately. Methods. Five chest pain scenarios were generated, with standardized prehospital ECGs accompanying each: three STEMI cases that should result in catheterization laboratory activation andtwo non-STEMI cases that should not. A convenience sample of paramedics in an urban/suburban EMS system examined each scenario andECG, andindicated whether the patient had STEMI andwhether they would activate the catheterization laboratory. A series of demographic andoperational questions were also asked of each participant. We report diagnostic statistics, agreement (kappa), and95% confidence intervals (CIs). Results. A convenience sample of 103 of 147 eligible paramedics (70%) was enrolled. For STEMI diagnosis, paramedics' sensitivity was 92.6% (95% CI 88.9–95.1) andspecificity was 85.4% (79.7–89.8); for catheterization laboratory activation, sensitivity was 88.0% (83.8–91.3) andspecificity was 88.3% (83.0–92.2). False-positive activation of the catheterization laboratory occurred in 8.1% (5.4–12.0) of cases. Of the STEMI cases, 94.1% were correctly read as STEMI, and91.0% had the catheterization laboratory appropriately activated. Of the non-STEMI cases, 14.9% were incorrectly read as STEMI, and12.0% had the catheterization laboratory inappropriately activated. The paramedics' comfort with calling a “chest pain alert” with no resulting catheterization laboratory activation (the current practice in this system) was not statistically different from their comfort with calling a chest pain alert if that call were to automatically result in catheterization laboratory activation (p > 0.05). Conclusions. Paramedics in an urban/suburban EMS system can diagnose STEMI andidentify appropriate cardiac catheterization laboratory activations with a high degree of accuracy, andan acceptable false-positive rate, when tested using paper-based scenarios.

The Need for Uniform Definitions in the Regionalized Care of ST‐segment Elevation Myocardial Infarction

The Need for Uniform Definitions in the Regionalized Care of ST‐segment Elevation Myocardial Infarction

Misinterpretation of Electrocardiograms and Cardiac Catheterization Laboratory Activations

To the Editor: In a prospective registry study of a regional ST-elevation myocardial infarction (STEMI) treatment program, Dr Larson and colleagues found that the “falsepositive” rate of cardiac catheterization laboratory activation ranged from 9% to 11%, depending on the definition used. As pointed out by Dr Masoudi in the accompanying Editorial, some degree of false-positive laboratory activation may be inevitable. In particular, current guidelines recommend an immediate invasive strategy over fibrinolytic therapy when the diagnosis of STEMI is uncertain, especially among patients at high risk of bleeding and intracranial hemorrhage. Furthermore, ancillary diagnostic tests such as echocardiography may have limited utility in differentiating between previous and acute myocardial infarction. Thus, to a certain extent, false-positive activation of cardiac catheterization laboratory may be entirely appropriate. This concept may be akin to the use of exploratory laparotomy for suspected appendicitis, where some falsepositive results are generally accepted given the potentially dire consequences of not identifying all patients with appendicitis. We believe that effective quality improvement efforts should aim to eliminate or minimize the misinterpretation of electrocardiograms (ECGs), which led to clearly inappropriate referrals for primary percutaneous coronary intervention in 1.8% of patients in this study. This prevalence was substantially lower than that reported in other, less selective multicenter observational studies, which may reflect the quality of initial training, ongoing support, and feedback for the selected participating sites in this registry. Widespread implementation of regional STEMI treatment programs without careful planning and proper quality control would be expected to have a much more profound adverse effect on resource usage. An important implication of the study by Larson et al is that, in addition to reporting the prevalence of falsepositive activation of the catheterization laboratory, elucidating the precise reasons for this activation (recognizing that some cases may be well justified) should be a key component of quality improvement measures for regional STEMI programs.

Misinterpretation of Electrocardiograms and Cardiac Catheterization Laboratory Activations—Reply

Misinterpretation of Electrocardiograms and Cardiac Catheterization Laboratory Activations—Reply

Misinterpretation of Electrocardiograms and Cardiac Catheterization Laboratory Activations—Reply

Misinterpretation of Electrocardiograms and Cardiac Catheterization Laboratory Activations—Reply

Effect of Prehospital 12-Lead Electrocardiogram on Activation of the Cardiac Catheterization Laboratory and Door-to-Balloon Time in ST-Segment Elevation Acute Myocardial Infarction

Reducing door-to-balloon (D + B) time during primary percutaneous coronary intervention for patients with ST-segment elevation myocardial infarction (STEMI) reduces mortality. Prehospital 12-lead electrocadiography (ECG) with cardiac catheterization laboratory (CCL) activation may reduce D + B time. Paramedic-performed ECG was initiated in the city of San Diego in January 2005 with STEMI diagnosis based on an automated computer algorithm. We undertook this study to determine the effect of prehospital CCL activation on D + B time for patients with acute STEMI brought to our institution. All data were prospectively collected for patients with STEMI including times to treatment and clinical outcomes. We evaluated 78 consecutive patients with STEMI from January 2005 to June 2006, and the study group consisted of all patients with prehospital activation of the CCL (field STEMI; n = 20). The control groups included concurrently-treated patients with STEMI during the same period who presented to the emergency department (nonfield STEMI; n = 28), and all patients with STEMI treated in the preceding year (2004) (historical STEMI; n = 30). Prehospital CCL activation significantly reduced D + B time (73 +/- 19 minutes field STEMI, 130 +/- 66 minutes nonfield STEMI, 141 +/- 49 minutes historical STEMI; p <0.001) with significant reductions in door-to-CCL and CCL-to-balloon times as well. The majority of patients with field STEMI achieved D + B times of <90 minutes (80% field STEMI, 25% nonfield STEMI, 10% historical STEMI; p <0.001). In conclusion, this study demonstrates that prehospital electrocardiographic diagnosis of STEMI with activation of the CCL markedly reduces D + B time.

“False-Positive” Cardiac Catheterization Laboratory Activation Among Patients With Suspected ST-Segment Elevation Myocardial Infarction

Allowing the emergency department physician to activate the cardiac catheterization laboratory is a key strategy to reduce door-to-balloon times in patients with ST-segment elevation myocardial infarction (STEMI). There are limited data on the frequency of "false-positive" catheterization laboratory activation in patients undergoing percutaneous coronary intervention for suspected STEMI. To determine the prevalence, etiology, and outcomes of false-positive cardiac catheterization laboratory activation in patients with a suspected STEMI. Prospective registry from a regional system that includes transfer of patients with STEMI from 30 community and rural hospitals with pretransfer catheterization laboratory activation for percutaneous coronary intervention at a tertiary cardiovascular center in Minnesota. A total of 1345 patients were enrolled from March 2003 to November 2006. Prevalence of false-positive catheterization laboratory activation in patients with suspected STEMI by 3 criteria: no culprit coronary artery, no significant coronary artery disease, and negative cardiac biomarker results. Of the 1335 patients with suspected STEMI who underwent angiography, 187 (14%; 95% confidence interval [CI], 12.2%-16.0%) had no culprit coronary artery and 127 (9.5%; 95% CI, 8.0%-11.2%) did not have significant coronary artery disease. Cardiac biomarker levels were negative in 11.2% (95% CI, 9.6%-13.0%) of patients. The combination of no culprit artery with negative cardiac biomarker results was present in 9.2% (95% CI, 7.7%-10.9%) of patients. Thirty-day mortality was 2.7% (95% CI, 0.4%-5.0%) without vs 4.6% (95% CI, 3.4%-5.8%) with a culprit coronary artery (P = .33). The frequency of false-positive cardiac catheterization laboratory activation for suspected STEMI is relatively common in community practice, depending on the definition of false-positive. Recent emphasis on rapid door-to-balloon times must also consider the consequences of false-positive catheterization laboratory activation.

155: Paramedic-Initiated Out-of-Hospital Cardiac Catheterization Lab Activation for Acute ST-Segment Elevation Myocardial Infarction Patients

Achieving and exceeding a door-to-balloon time (DBT) of 90 minutes with acute ST-segment elevation myocardial infarction (STEMI) patients receiving primary percutaneous coronary intervention (PCI) is challenging. Recognizing an acute STEMI in the out-of-hospital setting by paramedics could reduce DBT by early mobilization of the cardiac catheterization team.

Cardiac catheterization laboratory activation by the emergency physician without prior consultation decreases Door-to-Balloon time

Study objectives: The importance of minimizing door-to-balloon time (DTBT) in acute ST-segment elevation myocardial infarction (STEMI) is universally accepted. The purpose of this before-and-after study is to determine whether an emergency department (ED) strategy that calls for cardiac catheterization laboratory activation directly by the emergency physician is effective in decreasing DTBT. Methods: In our active community teaching hospital ED with an annual census of 55,000, the traditional practice for STEMI required cardiology consultation before cardiac catheterization laboratory notification. In November 2003, we instituted an ED protocol that mandated direct cardiac catheterization laboratory activation by the emergency physician for eligible STEMI patients without previous notification of the cardiologist. We measured clinically relevant intervals, including DTBT, before and after institution of the protocol. Only those meeting the following exclusion criteria, previous coronary artery bypass graft surgery, nursing home patient, dementia, do-not-resuscitate order, age older than 80 years, and dye allergy, were exempted from the study. Results: Twenty-four patients were enrolled after institution of the protocol; these were compared with 20 STEMI patients enrolled before the new protocol. DTBT decreased significantly, from 118 to 89 minutes (<i>P</i>=.039). Other ED parameters, including door to examination time (17 versus 15 minutes) and total ED time (80 versus 56 minutes, <i>P</i>=.056) decreased postprotocol but were not significantly different for the 2 periods. Those arriving by ambulance continued to have a significantly lower DTBT than nonambulance patients (preprotocol: Δ47 minutes, <i>P</i>=.03; postprotocol: Δ33 minutes; <i>P</i>=.012). Both groups were affected similarly by the change in protocol, decreasing DTBT by approximately 25%. Conclusion: We conclude that a strategy that mandates cardiac catheterization laboratory activation by the emergency physician for STEMI without previous cardiology consultation reduces DTBT.