Prehospital versus hospital fibrinolytic therapy using automated versus cardiologist electrocardiographic diagnosis of myocardial infarction: abortion of myocardial infarction and unjustified fibrinolytic therapy

Impact of telemedicine interventions on mortality in patients with acute myocardial infarction: a systematic review and meta-analysis

BACKGROUND

Despite the promise of telemedicine to improve care for ischaemic heart disease, there are significant obstacles to implementation. Demonstrating improvement in patient-centred outcomes is important to support development of these innovative strategies.

OBJECTIVE

To assess the impact of telemedicine interventions on mortality after acute myocardial infarction (AMI).

METHODS

Articles were searched in MEDLINE, Cochrane Central Register of Controlled Trials, Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), Base de Dados de Enfermagem (BDENF), Indice Bibliográfico Español en Ciencias de la Salud (IBECs), Web of Science, Scopus and Google Scholar, from January 2004 to January 2018. Study selection and data extraction were performed by two independent reviewers. In-hospital mortality (primary outcome), and door-to-balloon (DTB) time, 30-day mortality and long-term mortality (secondary outcomes) were assessed. Random effects models were applied to estimate pooled results.

RESULTS

Thirty non-randomised controlled and seven quasi-experimental studies were included (16 960 patients). They were classified as moderate or serious risk of bias by ROBINS-I (Risk Of Bias In Non-randomized Studies-of Interventions tool). In 31 studies, the intervention was prehospital ECG transmission. Telemedicine was associated with reduced in-hospital mortality compared with usual care (relative risk (RR) 0.63(95% confidence interval[CI] 0.55 to 0.72); I² <0.001%). DTB time was consistently reduced (mean difference -28 (95% CI -35 to -20) min), but showed large heterogeneity (I²=94%). Thirty-day mortality (RR 0.62;95% CI 0.43 to 0.85) and long-term mortality (RR 0.61(95% CI 0.40 to 0.92)) were also reduced, with moderate heterogeneity (I²=52%).

CONCLUSIONS

There is moderate-quality evidence that telemedicine strategies, in particular ECG transmission, combined with the usual care for AMI are associated with reduced in-hospital mortality and very-low quality evidence that they reduce DTB time, 30-day mortality and long-term mortality.

Pre-hospital versus in-hospital thrombolysis for ST-elevation myocardial infarction

BACKGROUND

Early thrombolysis for individuals experiencing a myocardial infarction is associated with better mortality and morbidity outcomes. While traditionally thrombolysis is given in hospital, pre-hospital thrombolysis is proposed as an effective intervention to save time and reduce mortality and morbidity in individuals with ST-elevation myocardial infarction (STEMI). Despite some evidence that pre-hospital thrombolysis may be delivered safely, there is a paucity of controlled trial data to indicate whether the timing of delivery can be effective in reducing key clinical outcomes.

OBJECTIVES

To assess the morbidity and mortality of pre-hospital versus in-hospital thrombolysis for STEMI.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (OVID), EMBASE (OVID), two citation indexes on Web of Science (Thomson Reuters) and Cumulative Index to Nursing and Allied Health Literature (CINAHL) for randomised controlled trials and grey literature published up to June 2014. We also searched the reference lists of articles identified, clinical trial registries and unpublished thesis sources. We did not contact pharmaceutical companies for any relevant published or unpublished articles. We applied no language, date or publication restrictions. The Cochrane Heart Group conducted the primary electronic search.

SELECTION CRITERIA

We included randomised controlled trials of pre-hospital versus in-hospital thrombolysis in adults with ST-elevation myocardial infarction diagnosed by a healthcare provider.

DATA COLLECTION AND ANALYSIS

Two authors independently screened eligible studies for inclusion and carried out data extraction and 'Risk of bias' assessments, resolving any disagreement by consulting a third author. We contacted authors of potentially suitable studies if we required missing or additional information. We collected efficacy and adverse effect data from the trials.

MAIN RESULTS

We included three trials involving 538 participants. We found low quality of evidence indicating uncertainty whether pre-hopsital thrombolysis reduces all-cause mortality in individuals with STEMI compared to in-hospital thrombolysis (risk ratio 0.73, 95% confidence interval 0.37 to 1.41). We found high-quality evidence (two trials, 438 participants) that pre-hospital thrombolysis reduced the time to receipt of thrombolytic treatment compared with in-hospital thrombolysis. For adverse events, we found moderate-quality evidence that the occurrence of bleeding events was similar between participants receiving in-hospital or pre-hospital thrombolysis (two trials, 438 participants), and low-quality evidence that the occurrence of ventricular fibrillation (two trials, 178 participants), stroke (one trial, 78 participants) and allergic reactions (one trial, 100 participants) was also similar between participants receiving in-hospital or pre-hospital thrombolysis. We considered the included studies to have an overall unclear/high risk of bias.

AUTHORS' CONCLUSIONS

Pre-hospital thrombolysis reduces time to treatment, based on studies conducted in higher income countries. In settings where it can be safely and correctly administered by trained staff, pre-hospital thrombolysis may be an appropriate intervention. Pre-hospital thrombolysis has the potential to reduce the burden of STEMI in lower- and middle-income countries, especially in individuals who have limited access to in-hospital thrombolysis or percutaneous coronary interventions. We found no randomised controlled trials evaluating the efficacy of pre-hospital thrombolysis for STEMI in lower- and middle-income countries. Large high-quality multicentre randomised controlled trials implemented in resource-constrained countries will provide additional evidence for the efficacy and safety of this intervention. Local policy makers should consider their local health infrastructure and population distribution needs. These considerations should be taken into account when developing clinical guidelines for pre-hospital thrombolysis.

To transmit or not to transmit: how good are emergency medical personnel in detecting STEMI in patients with chest pain?

BACKGROUND

There is growing use of prehospital electrocardiograms (ECGs) in establishing early diagnosis of ST segment myocardial infarction (STEMI) to facilitate early reperfusion. This study aimed to determine the predictive value of prehospital ECGs interpreted by nonphysician emergency medical services (EMS) in chest pain presentations.

METHODS

In our city of 658,700 people, EMS/paramedics received 21 hours of instruction on STEMI management, ECG acquisition, and interpretation. Suspected STEMI ECGs were wirelessly transmitted to and discussed with a physician for possible therapy. ECGs deemed negative for STEMI by EMS were not transmitted; patients were transported to the closest hospital without prehospital physician involvement.

RESULTS

From July 21, 2008 to July 21, 2010, there were 5426 chest pain calls to EMS, 380 were suspected STEMI cases. The remaining ECGs were deemed negative for STEMI by EMS. To audit the nontransmitted ECGs we analyzed 323 consecutive patients over 2 selected months (January and June 2010) for comparison. Of nontransmitted cases there was 1 missed and 2 STEMIs that developed subsequently. Based on 380 transmitted and 323 nontransmitted cases, the sensitivity and specificity of EMS detecting STEMI were 99.6% and 67.6%, respectively. The positive and negative predictive values for STEMI were 59.5% and 99.7%, respectively.

CONCLUSIONS

Our findings demonstrate nonphysician EMS interpretation of STEMI on prehospital ECG has excellent sensitivity and high negative predictive value. This finding supports the use of prehospital ECGs interpreted by EMS to help identify and facilitate treatment of STEMI. These results may have broad implications on staffing models for first responder/EMS units.

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

OBJECTIVE

Timely reperfusion therapy for ST-elevation myocardial infarction (STEMI) is an important determinant of outcome, yet targets for time to treatment are frequently unmet in North America. Prehospital strategies can reduce time to reperfusion. We sought to determine the extent to which emergency medical services (EMS) use these strategies in Canada.

METHODS

We carried out a cross-sectional survey in 2007 of ground EMS operators in British Columbia, Alberta, Ontario, Quebec and Nova Scotia. We focused on the use of 4 prehospital strategies: 1) 12-lead electrocardiogram (ECG), 2) routine expedited emergency department (ED) transfer of STEMI patients (from a referring ED to a percutaneous coronary intervention [PCI] centre), 3) prehospital bypass (ambulance bypass of local EDs to transport patients directly to PCI centres) and 4) prehospital fibrinolysis.

RESULTS

Ninety-seven ambulance operators were surveyed, representing 15 681 paramedics serving 97% of the combined provincial populations. Of the operators surveyed, 68% (95% confidence interval [CI] 59%-77%) had ambulances equipped with 12-lead ECGs, ranging from 40% in Quebec to 100% in Alberta and Nova Scotia. Overall, 47% (95% CI 46%-48%) of paramedics were trained in ECG acquisition and 40% (95% CI 39%-41%) were trained in ECG interpretation. Only 18% (95% CI 10%-25%) of operators had prehospital bypass protocols; 45% (95% CI 35%-55%) had protocols for expedited ED transfer. Prehospital fibrinolysis was available only in Alberta. All EMS operators in British Columbia, Alberta and Nova Scotia used at least 1 of the 4 prehospital strategies, and one-third of operators in Ontario and Quebec used 0 of 4. In major urban centres, at least 1 of the 3 prehospital strategies 12-lead ECG acquisition, bypass or expedited transfer was used, but there was considerable variation within and across provinces.

CONCLUSION

The implementation of widely recommended prehospital STEMI strategies varies substantially across the 5 provinces studied, and relatively simple existing technologies, such as prehospital ECGs, are underused in many regions. Substantial improvements in prehospital services and better integration with hospital-based care will be necessary in many regions of Canada if optimal times to reperfusion, and associated outcomes, are to be achieved.

Prognostic significance and magnetic resonance imaging findings in aborted myocardial infarction after primary angioplasty

BACKGROUND

Aborted myocardial infarction (MI) is defined by major (> or =50%) ST-segment resolution and a lack of subsequent cardiac enzyme rise > or =2 the upper normal limit. This ultimate myocardial salvage has been observed in approximately 15% of ST-elevation MI (STEMI) patients after fibrinolysis. So far, the prognostic significance and magnetic resonance imaging (MRI) findings of an aborted MI after primary angioplasty have not been evaluated appropriately.

METHODS

We examined 420 consecutive STEMI patients undergoing primary angioplasty within 12 hours after symptom onset. All patients underwent MRI within 1 to 4 days. Clinical end points were major adverse cardiovascular events within 6 months after the index event.

RESULTS

Of the 420 STEMI patients, 58 (14%) fulfilled aborted MI criteria. As compared with true MI, patients with aborted MI had a significant lower infarct size, shorter pain-to-balloon time, and better left ventricular ejection fraction (P < .001, respectively). Aborted MI patients had a 6-month major adverse cardiovascular event rate of 1.7% versus 19.6% of true MI patients (P = .001). In aborted MI patients, MRI detected no myocardial scar in 30 (56%), and a minor necrosis/scar formation in 24 patients (44%).

CONCLUSION

The proven prognostic relevance of aborted MI makes it a meaningful end point and therapeutic target in future MI studies. MRI can further distinguish between true aborted MI with absence of myocardial scar and aborted MI with scar formations.

Paramedic transtelephonic communication to cardiologist of clinical and electrocardiographic assessment for rapid reperfusion of ST-elevation myocardial infarction

BACKGROUND/PURPOSE

We tested the hypothesis that paramedic recognition of ST-elevation myocardial infarction (STEMI) and cardiologist activation of the cardiac catheterization laboratory without transmission of the electrocardiogram reduces door-to-balloon times.

METHODS

We studied a consecutive series of patients suspected to have STEMI who were taken to the cardiac catheterization laboratory in the 6-month period before hotline implementation (historical controls) and during the first year of hotline use (intervention group, hotline; emergency medical service patients without hotline, concurrent controls).

RESULTS

Emergency medical services activated the hotline 47 times, and 25 patients were subsequently taken to the catheterization laboratory. Patients who received PCI involving hotline use (n = 20) had significantly shorter door-to-balloon times (58 minutes; 25th-75th percentile, 52-73 minutes) than historical controls (n = 15) (112 minutes; 25th-75th percentile, 81-137; P < .0001) and concurrent controls (n = 15) (92 minutes; 25th-75th percentile, 76-112; P = .019).

CONCLUSIONS

Paramedic transtelephonic communication to cardiologist of clinical and electrocardiogram assessment resulted in a 54-minute reduction in door-to-balloon time for patients with STEMI.

Meanaging Knowledge for the emergency care of heart attack patients: Paramedics and thrombolytic treatment

The objective of this paper is to examine the Knowledge Management(KM) paradigm in the context of UK paramedics' assessment and treatment of patients with suspected acute myocardial infarction (MI) or ;heart attack' We outline the role of thrombolytic therapy and other aspects of emergency cardiac care and discuss how contemporary KM tools and techniques can be used to support the development and retention of key clinical skills and knowledge in this emerging field of parcice.

The value of both ST-segment and QRS complex changes during acute coronary occlusion for prediction of reperfusion-induced myocardial salvage in a canine model

BACKGROUND

Analysis of ST-segment elevation for assessment of patients with suspected acute coronary occlusion is in widespread use for diagnostic and prognostic purposes. In this study, changes in the QRS complex also were analyzed to determine if these changes that are seldom used clinically can provide additional prognostic information. An acute coronary occlusion canine model, in which direct measurements of myocardial salvage were made, was used to assess whether ST-segment and QRS complex changes during coronary occlusion yielded independent estimates of the amount of salvage provided by reperfusion with arterial blood.

METHODS AND RESULTS

Continuous electrocardiographic recordings were obtained from 14 study dogs undergoing a 90-minute period of coronary artery occlusion in which the severity of the ischemia during the occlusion was estimated at 10 and 45 minutes by microsphere injections. After 3 hours of reperfusion, the myocardium at risk and postmortem infarct size was measured. Myocardial salvage correlated inversely with both ST-segment elevation (r = -0.85; P < .0001), and QRS complex prolongation (r = -0.72; P = .003). When dogs were paired so that they had equal amounts of ST elevation but differed with respect to the presence of QRS prolongation, less myocardial salvage was found in those with QRS prolongation. The independent value of QRS prolongation was supported further by the observation that presence of QRS prolongation resulted in a loss of the highly significant correlation between ST elevation and salvage (r = -0.60; P = .2).

CONCLUSIONS

High magnitudes of ST elevation are correlated significantly with less myocardial salvage. Moreover, for a given magnitude of ST elevation, the presence of concurrent QRS prolongation is associated with even less myocardial salvage.

Prehospital fibrinolysis

Reperfusion therapy for ST-elevation acute coronary syndromes aims at early and complete recanalization of the infarct-related artery to salvage myocardium and improve both early and late clinical outcomes. Prehospital diagnosis of ST-elevation acute coronary syndrome can be made by electrocardiography with or without transtelephonic transmission, and subsequent fibrinolytic therapy can be instituted at home or in the ambulance. Prehospital fibrinolysis decreases time to treatment by approximately 1 hour compared with in-hospital therapy resulting in a significant 15% relative risk reduction in early mortality. This may compare well with primary angioplasty for ST-elevation acute coronary syndrome, although more studies are necessary.

Bypassing the emergency room reduces delays and mortality in ST elevation myocardial infarction: the USIC 2000 registry

OBJECTIVE

To study the impact on outcomes of direct admission versus emergency room (ER) admission in patients with ST-segment elevation myocardial infarction (STEMI) DESIGN: Nationwide observational registry of STEMI patients

SETTING

369 intensive care units in France.

INTERVENTIONS

Patients were categorised on the basis of the initial management pathway (direct transfer to the coronary care unit or catheterisation laboratory versus transfer via the ER).

MAIN OUTCOME MEASURES

Delays between symptom onset, admission and reperfusion therapy. Mortality at five days and one year.

RESULTS

Of 1204 patients enrolled, 66.9% were admitted direct and 33.1% via the ER. Bypassing the ER was associated with more frequent use of reperfusion (61.7% v 53.1%; p = 0.001) and shorter delays between symptom onset and admission (244 (interquartile range 158) v 292 (172) min; p < 0.001), thrombolysis (204 (150) v 258 (240) min; p < 0.01), hospital thrombolysis (228 (156) v 256 (227) min, p = 0.22), and primary percutaneous coronary intervention (294 (246) v 402 (312) min; p < 0.005). Five day mortality rates were lower in patients who bypassed the ER (4.9% v 8.6%; p = 0.01), regardless of the use and type of reperfusion therapy. After adjusting for the simplified Thrombolysis in Myocardial Infarction (TIMI) risk score, admission via the ER was an independent predictor of five day mortality (odds ratio 1.67, 95% confidence interval 1.01 to 2.75).

CONCLUSIONS

In this observational analysis, bypassing the ER was associated with more frequent and earlier use of reperfusion therapy, and with an apparent survival benefit compared with admission via the ER.

Consideration of Pitfalls in and Omissions from the Current ECG Standards for Diagnosis of Myocardial Ischemia/Infarction in Patients Who Have Acute Coronary Syndromes

The ECG is the key clinical test available for the emergency determination of which patients who presenting with acute coronary syndromes indeed have acute myocardial ischemia/infarction. Because typically the etiology is thrombosis, the correct clinical decision regarding reperfusion therapy is crucial. This review follows the efforts of an AHA working group to develop new standards for clinical application of electrocardiology. The pitfalls in the current diagnostic standards regarding ischemia/infarction that have been identified by sufficiently documented studies are corrected in their report. This article focuses on the pitfalls for which new standards will emerge in future years.

Aborted myocardial infarction: a new target for reperfusion therapy

Reperfusion therapy for ST-elevation acute coronary syndromes aims at early and complete recanalization of the infarct-related artery in order to salvage myocardium and improve both early and late clinical outcomes. Myocardial necrosis is usually confirmed and quantified by myocardial enzyme release in plasma. However, over 10% of patients treated with reperfusion therapy fail to develop an enzyme rise, but do exhibit transient ECG changes, which are consistent with an aborted myocardial infarction. The earlier the reperfusion therapy is instituted, the higher the incidence of aborted infarction. Treatment within an hour after symptom onset may result in 25% of aborted infarction and is in combination with complete (70%) ST-segment resolution associated with better survival. This endpoint is easy to define and occurs promptly in time. The faster that effective treatment is initiated, the more likely aborted infarction will occur. Given that mortality, re-infarction, and stroke are declining in incidence, we suggest the introduction of aborted infarction as an endpoint in clinical trials of ST-elevation acute coronary syndromes.

Comparative accuracy of manual versus computerized electrocardiographic measurement of J-, ST- and T-wave deviations in patients with acute coronary syndrome

Accurate and rapid electrocardiographic interpretation is of crucial importance in acute coronary syndrome (ACS). Computerized electrocardiographic algorithms are often used in out-of-hospital settings. Their accuracy should be carefully validated in ACS, particularly in ST-elevation myocardial infarction. This study evaluated the comparative accuracy of lead-specific computer-based versus manual measurements of the J-point, ST-segment, and T-wave deviations in standard 12-lead electrocardiograms (ECGs) (excluding lead aVR). Sixty-nine consecutive patients with suspected ACS were included. The interobserver reliability in the determination of ST-segment deviation>or=0.2 mV in leads V2 and V3 was very good (kappa=0.94 and 0.93, respectively). Agreement between a cardiologist and the computer regarding ST elevation>or=0.2 mV in lead V2 was moderate (kappa=0.72) and in V3 was very good (kappa=0.85). For ST depression or elevation>or=0.05 mV in lead LIII, agreement was good and moderate (kappa=0.79 and 0.51, respectively). Bland-Altman analysis demonstrated clinically acceptable limits of agreement comparing measurements of the J point and the T wave, but clinically inadequate limits of agreement with respect to ST-segment deviation, between the electrocardiographer and the computer. The optimal cut-off points were 0.115 mV (sensitivity 89%, specificity 98%) for the computer program to detect ST elevation>or=0.2 mV and 0.045 mV (sensitivity 74%, specificity 99%) for revealing ST elevation>or=0.1 mV. It was found that automatically measured ST-segment deviations were smaller than those manually measured. In conclusion, a correction should be performed to obtain optimal results in the automated analysis of ECGs, because the results have important implications for clinical decision making.

Appropriate invasive and conservative treatment strategies for patients with ST elevation myocardial infarction

PURPOSE OF REVIEW

The goal of treatment strategies for patients with ST elevation myocardial infarction is to reperfuse the occluded coronary artery, as rapidly and safely as possible. This review discusses evidence regarding the appropriate treatment strategy for patients with ST elevation myocardial infarction taking into consideration geographical and logistical barriers.

RECENT FINDINGS

Primary percutaneous coronary intervention is considered the gold standard of myocardial reperfusion. As therapy is time dependent, logistical barriers limit its use to no more than 29% of ST elevation myocardial infarction patients worldwide. Most patients with ST elevation myocardial infarction who undergo primary angioplasty achieve mechanical reopening of the infarct-related artery beyond the established time limit from which left ventricular preservation and clinical benefit are less probable. In contrast, early administration of newer fibrin-specific thrombolytics is at least as effective as primary angioplasty, and can abort infarction and dramatically reduce mortality when given during the first 1-2 hours of onset. Consequently, key elements from the current guidelines recommend that patients with ST elevation myocardial infarction should be reperfused either by primary percutaneous coronary intervention performed 90 minutes after the first medical contact or by thrombolysis within 30 minutes of presentation to hospital. These advantages and disadvantages should generate distinct viewpoints on reperfusion strategies for patients with infarction. For patients admitted in a hospital with primary percutaneous coronary intervention facilities, this should be considered the reperfusion strategy. Options for patients admitted to community hospitals without percutaneous coronary intervention facilities include administration of fibrinolysis or transfer to a tertiary care center for primary percutaneous coronary intervention.

SUMMARY

Implementation of reperfusion strategies should vary based on the mode of transportation of the patient and capabilities at the receiving hospital.

Real-time paramedic compared with blinded physician identification of ST-segment elevation myocardial infarction: results of an observational study

The aim of the study were to determine if paramedics can accurately identify ST-segment elevation myocardial infarction (STEMI) on prehospital 12-lead (PHTL) electrocardiogram and to compare paramedic with blinded physician identification of STEMI. Paramedics identified definite STEMI, or possible acute myocardial infarction but not definite, and nondiagnostic. Two blinded readers (cardiologist and emergency physician) independently categorized each PHTL. A third reviewer assigned final diagnoses and determined whether the PHTL met STEMI criteria. One hundred sixty-six PHTL were acquired over an 8-month period. Fifteen were excluded from analysis. Sixty-two percent of the patients (94/151) were male, mean age was 61.1 years (+/-14.8 SD, range 20-92 years), and 81% had chest pain. Twenty-five patients (16.6%; 95% confidence interval [CI], 11%-23.5%) had confirmed STEMI and 16 (10.6%) had confirmed non-STEMI acute myocardial infarction. Paramedic sensitivity was 0.80 (95% CI, 0.64-0.96); specificity was 0.97 (95% CI, 0.94-1.00) with positive likelihood ratio of 25.2 and negative likelihood ratio of 0.21. Overall accuracy was similar for paramedic and physician reviewers (0.94, 0.93, 0.95). Highly trained paramedics in an urban emergency medical services system can identify patients with STEMI as accurately as blinded physician reviewers.

Reduction of treatment delay in patients with ST-elevation myocardial infarction: impact of pre-hospital diagnosis and direct referral to primary percutanous coronary intervention

AIMS

The majority of patients with ST-elevation myocardial infarction (STEMI) are admitted to local hospitals without primary percutaneous coronary intervention (primary PCI) facilities. Acute transferral to an interventional centre is necessary to treat these patients with primary PCI. The present study assessed the reduction in treatment delay achieved by pre-hospital diagnosis and referral directly to an interventional centre.

METHODS AND RESULTS

Two local hospitals without primary PCI facilities were serving the study region. Pre-hospital diagnoses were established with the use of telemedicine, by ambulance physicians, or by general practitioners. Primary PCI was accepted as the preferred reperfusion therapy in patients with STEMI. From 31 October 2002 to 31 January 2004 all patients transported by ambulance and transferred for primary PCI were registered. Patients with STEMI were divided into three groups: (A) patients diagnosed at a local hospital (n = 55), (B) patients diagnosed pre-hospitally and admitted to a local hospital (n = 85), and (C) patients diagnosed pre-hospitally and referred directly to the interventional centre (n = 21). When comparing group A with group B and C, no difference was found in age, sex, infarct location, or distance from the scene of event to the interventional centre, whereas the median time from ambulance call to first balloon inflation was 41 min shorter in group B compared with group A (P<0.001) and 81 min shorter in group C compared with group A (P<0.001).

CONCLUSION

In a cohort of patients scheduled for admission to a local hospital and subsequent transferral to an interventional centre for primary PCI, those diagnosed pre-hospitally had shorter treatment delay compared with those diagnosed in hospital, both in the setting of initial admission to a local hospital, and to an even larger extent in the setting of referral directly to the interventional centre.