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Department of Cardiology, Rigshospitalet, University of Copenhagen, DenmarkDepartment of Cardiology, Køge Hospital, University of Copenhagen, DenmarkInterventional Cardiovascular Research and Clinical Trials, The Zena and Michael A. Wiener Cardiovascular Institute, The Icahn School of Medicine at Mount Sinai, New York, New York
Interventional Cardiovascular Research and Clinical Trials, The Zena and Michael A. Wiener Cardiovascular Institute, The Icahn School of Medicine at Mount Sinai, New York, New York
Interventional Cardiovascular Research and Clinical Trials, The Zena and Michael A. Wiener Cardiovascular Institute, The Icahn School of Medicine at Mount Sinai, New York, New York
Adequate health care is increasingly dependent on prehospital systems and cardiovascular (CV) disease remains the most common cause for hospital admission. However the prevalence of CV dispatches of emergency medical services (EMS) is not well reported and survival data described in clinical trials and registries are subject to selection biases. We aimed to describe the prevalence and prognosis of acute CV disease and the effect of invasive treatment, in an unselected and consecutive prehospital cohort of 3,410 patients calling the national emergency telephone number from 2005 to 2008 with follow-up in 2013. Individual-level data from national registries were linked to the dedicated EMS database of primary ambulance dispatches supported by physician-manned emergency units. Outcome data were obtained from the Central Population Registry, the National Patient Registry, and the National Registry of Causes of Death. In patients calling the national emergency telephone number, a CV related ambulance alarm code was given in 2,541 patients of 3,410 patients (74.5%) resulting in 2,056 of 3,410 primary CV discharge diagnoses (60.3%) with a 30-day and 5-year all-cause mortality of 24.5% and 46.4%, respectively. Stroke, acute heart failure, and ST-segment elevation myocardial infarction (STEMI) carried a 25- to 50-fold adjusted mortality hazard during the first 4 days. In patients with suspected STEMI, 90.5% had an acute angiography performed. Nontransferred, nonreperfused patients with STEMI (9.1%) carried 80% short-term mortality. Noninvasive management of non–ST-segment elevation myocardial infarction was common (37.9%) and associated with an increased adjusted long-term mortality hazard (hazard ratio 4.17 [2.51 to 8.08], p <0.001). Survival in 447 out-of-hospital cardiac arrest patients (13.1%) was 11.6% at 30 days. In conclusion, patients with a CV ambulance alarm call code and a final CV discharge diagnosis constitute most patients handled by EMS with an extremely elevated short-term mortality hazard and a poor long-term prognosis. Although co-morbidities and frailty may influence triage, this study emphasizes the need for an efficient prehospital phase with focus on CV disease and proper triage of patients suitable for invasive evaluation if the outcomes of acute heart disease are to be improved further in the current international context of hospitals merging into highly specialized entities resulting in longer patient transfers.
An uncovered need remains for investigating the true underlying mortality rates in acute cardiovascular (CV) disease. Recently, a national Danish survey based on the National Patient Registry, in which all hospitalized patients are coded according to the International Classification of Diseases (ICD-10), showed a 14.8% (confidence interval 14.5% to 15.2%) 30-day mortality rate from 2004 to 2008 for all myocardial infarctions diagnoses (ICD I21 diagnoses: ST-segment elevation myocardial infarction [STEMI], non–ST-segment elevation myocardial infarction [NSTEMI], and unspecified myocardial infarction [MI]),
25 year trends in first time hospitalisation for acute myocardial infarction, subsequent short and long term mortality, and the prognostic impact of sex and comorbidity: a Danish nationwide cohort study.
USIK USIC 2000 InvestigatorsFAST MI Investigators Association of changes in clinical characteristics and management with improvement in survival among patients with ST-elevation myocardial infarction.
Because of this mortality discrepancy between randomized clinical trials, registries, and national data, we relied on a prehospital register of patients with a potential upstream acute CV diagnosis, enabling us to follow primary discharge diagnoses of patients calling emergency medical services (EMS) for suspected CV disease, rather than relying on acute coronary syndrome (ACS) discharge diagnoses obtained after admission at the invasive center in a consequently selected patient population. To describe the burden of CV disease in an EMS setting is important, as adequate health care is increasingly dependent on elaborate prehospital systems because hospitals condensate into fewer and highly specialized entities, conjoining smaller or rural hospitals and thereby enhancing catchment areas and transfer distances. We aimed to describe the prevalence and prognosis of CV disease in an upstream unselected prehospital cohort of patients calling the national emergency telephone number, for example 112 or 911.
Methods
We investigated a consecutive Danish cohort of 4,083 patient contacts with EMS in Storstrøm County in the southern part of Zealand (262,781 inhabitants and 3,398 km2). The former Storstrøm county is a nonurban region of small cities with <45,000 inhabitants and confluent suburban areas, as well as large areas of rural character. The rate of elderly citizens >75 years of age is higher than the national average. Population increase, educational level, employment rate, and self-assessed health are lower than the national average, whereas the average alcohol and cigarette consumption and the incidence of long-term sick leave are above national average.
Pre-hospital diagnosis and transfer of patients with acute myocardial infarction: a decade long experience from one of Europe's largest STEMI networks.
Usually the first EMS to arrive at scene is the primary ambulance staffed by emergency medical technicians or paramedics. These primary ambulances are supported by emergency medical units manned with physicians. A patient contact was registered every time a patient called the national emergency telephone number, activating a primary ambulance and physician-manned unit. Calls that did not result in an ambulance dispatch were not registered. Patients were entered, regardless of vital status at the arrival of EMS and regardless of being permanent residents in Storstrøm county. We only considered the first admission of every patient and excluded 641 (15.7%) register entries of patients repeatedly admitted by EMS (Figure 1).
Figure 1Flow chart. We identified a total of 447 cases with OHCA. The OHCA group (n = 338) depicted in the flow chart is exclusively constituted by nonresuscitated patients and patients who were resuscitated but died immediately after without having obtained any diagnosis leading to the cardiac arrest. Resuscitated patients and patients without return of spontaneous circulation but with a specific diagnosis for the cardiac arrest are included under their respective diagnosis.
The physician-manned units are fast vehicles without the space to transport patients, but are dispatched simultaneously with the primary ambulance to the injury site for a so-called “rendezvous” with the primary ambulance at the injury site or on the way, to triage and initiate advanced treatment for stabilization before transport. Patients were transferred to 2 around the clock invasive centers in Copenhagen and 4 noninvasive hospitals within the county.
We linked individual-level data from national registries to the dedicated prehospital EMS database, using the personal registration number provided to all Danish residents. The inclusion period was May 1, 2005, to January 31, 2008, with follow-up from May 6, 2013, to May 14, 2013. The EMS database contained data entries based on ambulance charts reporting time information on alarm call, arrival at scene, departure from scene and hospital arrival, vital parameters, and the tentative prehospital diagnosis. Outcome data were obtained from the Central Population Registry, the National Patient Registry, and the National Registry of Causes of Death, enabling follow-up of all patients who had not emigrated. Long-term follow-up was at least 5 years in all patients, maximum follow-up was 8 years, and median follow-up was 5 years and 6 months.
Patients were categorized according to their primary discharge diagnosis based on the ICD-10 codes. STEMI was defined by the ICD-10 codes I210B, I211B, and I213, and NSTEMI was defined by the codes I210A, I211A, and I214. The diagnosis of MI has been validated in the National Patient Registry.
The validity of the diagnosis of acute myocardial infarction in routine statistics: a comparison of mortality and hospital discharge data with the Danish MONICA registry.
Patients treated invasively with diagnostic coronary angiography, percutaneous coronary intervention (PCI), or coronary artery bypass grafting (CABG) were also registered in the eastern Denmark PCI database. Non specified MI was defined by I219. In these patients, we applied all available data from the registries, as well as the eastern Denmark PCI database and individual discharge letter reviews, to allocate I219 to either the STEMI or NSTEMI group. Unstable angina pectoris (UAP) was defined by I200 and also by I208, I209 and I259, as patients in this population called 112 for chest pain due to acute onset or aggravation of known angina pectoris. ACS rule-out diagnosis was defined by a discharge diagnosis Z034, Z035, and R072-74. Heart failure was defined by I420, I500-509, and R570; atrial fibrillation by I48-I489; and out-of-hospital cardiac arrest (OHCA) by ambulance charts and I46-I469 at emergency room arrival. The term OHCA covers both patients with community cardiac arrest and cardiac arrest during ambulance transfer. Chronic kidney disease was defined by N17-19. The study was approved by the Danish Data Protection Agency (2011-41-5849) and the National Board of Health (7-505-29-1710/1/FSE).
Continuous variables are presented as mean ± SD. The independent samples t test was used for comparison. Discrete data are presented as frequencies and percentages. The chi-square test, Fisher's exact test, Mann-Whitney test, and Kruskal-Wallis test were used for comparison of categorical and continuous variables as appropriate. Mortality hazards were adjusted for age and gender in multivariate Cox regression analysis. Hazard ratios are presented according to time interval after admission by EMS with patients discharged with an ACS rule-out diagnosis as the reference group. Independent predictors of all-cause 30-day to 5-year mortality in non–ST-segment elevation (NSTE)-ACS were identified using Cox proportional hazard regression analysis. We excluded patients with STEMI from the prediction analysis of invasive management, as patients with STEMI per definition are invasively managed because of the Danish national reperfusion strategy with primary percutaneous coronary intervention (pPCI).
The Primary Coronary Angioplasty vs. Thrombolysis Group Does time matter? A pooled analysis of randomized clinical trials comparing primary percutaneous coronary intervention and in-hospital fibrinolysis in acute myocardial infarction patients.
The statistical significance level was p <0.05 (2-sided test). Data were analyzed using the PASW Statistics 18 software package (SPSS Inc., Chicago, Illinois).
Results
In 3,442 consecutive patient contacts calling the national emergency telephone number, follow-up was 99.2% complete; thus, we included 3,410 patients. A CV related diagnosis by ambulance call alarm code was given in 2,541 (74.5%) of patients and a CV related final primary discharge diagnosis in 2,056 (60.3%) of patients (Figure 1). Of these, 1,294 (38%) patients were discharged with an ischemic heart disease–related diagnosis. Baseline characteristics and crude mortality rates according to discharge diagnosis are listed in Tables 1 and 2, respectively.
Table 1Baseline variables
STEMI
NSTEMI
UAP
ACS rule out
Variable
(n=275)
(n=211)
(n=321)
(n=497)
Men
198 (72%)
133 (63%)
216 (67.3%)
290 (58.4%)
Age (years)
65.0 ± 13.1
71.2 ± 13.1
68.5± 13.3
62.9 ± 15.7
Diabetes mellitus
41 (14.9%)
37 (17.5%)
63 (19.6%)
72 (14.5%)
Chronic kidney disease
9 (3.3%)
21 (10%)
20 (6.2%)
15 (3%)
Prior myocardial infarction
35 (12.7%)
58 (27.5%)
98 (30.5%)
50 (10.1%)
Prior percutaneous coronary intervention
19 (6.9%)
25 (11.8%)
78 (24.3%)
33 (6.6%)
Prior coronary artery bypass
3 (1.1%)
9 (4.3%)
41 (12.8%)
9 (1.8%)
Prior stroke
9 (3.3%)
17 (8.1%)
24 (7.5%)
33 (6.6%)
Invasive management (Total of CAG without PCI, PCI, CABG)
Table 2All-cause mortality rates n (%) for each diagnosis category. Patients with out of hospital cardiac arrest are included in each respective category in case they were resuscitated and obtained a specific diagnosis. Nonresuscitated OHCA patients (n = 338) are included in the total cardiovascular category
Patients with a primary STEMI discharge diagnosis were invasively investigated in 90.5% of cases. Those treated with pPCI within 12 hours had a 30-day mortality of 6.3%, whereas patients who did not undergo any attempt of reperfusion had a 30-day mortality rate of 80% (Table 3). The reasons for nonreperfusion were death at the local hospital before transfer in 17 cases (68%) and 4 patients (16%) were judged too frail. Three patients (12%) were not accepted by the attending cardiologist at the pPCI center, and 1 patient (4%) refused transfer. Nonreperfused patients were significantly older (median 81 years [interquartile range 70 to 87] vs 64 [interquartile range 55 to 73], p <0.001), more often women (48% vs 26%, p = 0.019), had higher incidence of previous stroke (16% vs 2%, p <0.001) and diabetes (32% vs 13.2%, p = 0.012), presented more often with prehospital hypotension (35.1% vs 15%, p = 0.022) and tachycardia (57.1% vs 25.4%, p = 0.002), and more frequently had OHCA before admission at the non-pPCI center (24% vs 10.8%, p = 0.053).
Table 3Mortality rates in STEMI patients according to treatment
N
30 day
1 year
3 year
5 year
Primary percutaneous coronary intervention
222 (80.7%)
14 (6.3%)
19 (8.6%)
30 (13.5%)
45 (20.3%)
Percutaneous coronary intervention >12 hours
11 (4%)
1 (9.1%)
3 (27.6%)
3 (27.6%)
7 (63.6%)
Acute coronary artery bypass graft
8 (2.9%)
0 (0%)
0 (0%)
0 (0%)
0 (0%)
Acute coronary angiography, no percutaneous coronary intervention
In patients with NSTEMI, an angiography was performed in 62.1% of the cases. Of these, 34.6% were treated by PCI within 30 days and 9% by CABG within 90 days, and 37.9% were noninvasively managed. In patients with UAP, 17.4% of patients had an angiography performed, whereas 4.7% were treated by PCI within 30 days and 3.4% by CABG within 90 days, and 82.6% were noninvasively managed. The mortality rates according to treatment for patients with NSTE-ACS are listed in Table 4. Noninvasively treated patients with NSTE-ACS had higher all-cause mortality in the period from 30 days to 5 years (41.5% vs 18.6%, p <0.001) compared with invasively handled patients with a coronary angiography (CAG) <30 days. Patients without invasive management were older (71.6 ± 13.1 vs 65.7 ± 12.8, p <0.001) and had a higher burden of CV disease in terms of more known ischemic heart disease (51.8 vs 39.7%, p = 0.008) and CABG (12.2% vs 3.9% p = 0.002). In patients with NSTEMI, prehospital tachycardia (Heart rate >100; 54.3% vs 28.4%. p <0.001) was more frequent in patients without invasive management. There were no differences for gender, known chronic kidney disease, previous stroke, and diabetes.
Table 4Mortality in NSTE-ACS (NSTEMI and UAP) patients according to treatment. Only invasive treatment within the first 30 days after index admission was considered
Medical management without subacute CAG performed within 30 days was independently associated with 30-day and 5-year all-cause mortality. Other independent long-term predictors were age, gender, diabetes, chronic kidney disease, prehospital tachycardia, and an NSTEMI diagnosis (Table 5). Age and gender adjusted hazard ratios are shown in Figure 2. All CV diagnoses had substantially elevated risk of all-cause mortality during the first 4 days after admission, which mitigated to nonsignificant hazard levels after 30 days from EMS admission, except for patients with NSTEMI, heart failure and stroke, where mortality risk remained significantly elevated during the 5-year follow-up.
Table 5Predictors of all-cause 30-day to 5-year mortality by Cox proportional hazard in 532 NSTE-ACS patients (NSTEMI, UAP). All baseline variables from Table 1 were tested, and only univariable predictors (P <0.1) and gender were entered in the multivariable model
Hazard ratio (HR) compared to CAG ≤30 days. CABG within 90 days did not carry any additional risk. Non-invasively managed patients had no coronary angiography performed within 30 days.
3.69 (2.04 – 6.67)
<0.001
4.17 (2.51- 8.08)
<0.001
NSTEMI vs. UAP
1.39 (1.01 – 1.87)
0.041
1.87 (1.28 - 2.73)
<0.001
MI = myocardial infarction.
∗ Hazard ratio (HR) compared to CAG ≤30 days. CABG within 90 days did not carry any additional risk. Non-invasively managed patients had no coronary angiography performed within 30 days.
Mortality rates for 447 (13.1%) patients with OHCA according to resuscitation and initial retrievable rhythm are listed in Table 6. Thirty-three (12%) patients with STEMI had OHCA; of those, 19 patients (57.6%) were EMS witnessed during ambulance transfer and 14 (43.4%) were bystander witnessed before ambulance arrival. Patients with STEMI with OHCA had a significantly elevated 30-day mortality compared with all patients with STEMI without OHCA (30.3 vs 12.4%, p = 0.004). However, the excess mortality was confined to patients who suffered community-based OHCA (57.1 vs 12.4% p = 0.004), as patients with STEMI who experienced EMS-witnessed OHCA had no excess mortality (10.5 vs 12.4%, p = 0.84), in comparison to patients with STEMI without OHCA.
Table 6Survival in patients with out-of-hospital cardiac arrest (OHCA)
Seventeen (3.2%) patients with NSTE-ACS had OHCA with significantly higher 30-day mortality (41.2% vs 5%, p <0.001) and 5-year mortality (70.6% vs 36.3%, p <0.001) than patients with NSTE-ACS without OHCA. None of the baseline variables were associated with OHCA in patients with NSTE-ACS, but patients with OHCA tended to be younger (65.3 ± 12.5 vs 69.7 ± 12.3, p = 0.186).
Discussion
In this large unselected cohort of patients dialing for EMS, most patients (75%) handled in the prehospital phase by physician-manned EMS received a CV alarm call code, and 6 of 10 admitted patients received a final primary CV hospital discharge diagnosis. These CV patients carried a poor long-term prognosis with a very elevated acute 4-day mortality hazard. The 30-day mortality rates in this unselected prehospital population including nontransferred and nonreperfused patients with ACS with nonspecific MI diagnoses were 14.5% for patients with STEMI and 10% for patients with NSTEMI. These incidences suggest considerably higher actual population rates than reported in randomized clinical trials (2% to 5% for STEMI
USIK USIC 2000 InvestigatorsFAST MI Investigators Association of changes in clinical characteristics and management with improvement in survival among patients with ST-elevation myocardial infarction.
By including upstream patients evaluated by EMS, we are privy to the adverse outcomes of CV disease without the selection bias of making it to the hospital. Despite our dire mortality results, the findings are quite actionable. This is elucidated by the substantially better survival of patients with STEMI with EMS-witnessed cardiac arrest, compared with community based cardiac arrest in patients with STEMI and the very differential rates of return of spontaneous circulation in patients with ventricular fibrillation or tachycardia compared with asystole/pulseless electric activity.
Developing an analytical tool for evaluating EMS system design changes and their impact on cardiac arrest outcomes: combining geographic information systems with register data on survival rates.
Our results therefore highlight the need of immediate and seamless EMS processes and early referral to invasive centers, also stressed by another central finding; although the large majority of patients with STEMI (90.5%) were treated with pPCI due to the Danish national reperfusion strategy,
the ≈10% of patients that were never transferred to a tertiary pPCI center nor perfused largely accounted for the elevated 30-day mortality of 14.5%. Nontransferred patients with STEMI were more likely to be frail elderly women with acute and chronic co-morbidities. Whether the 80% 30-day mortality rate in nontransferred patients was an inevitable outcome despite best clinical practice, or whether apt resources had not been allocated properly in these patients cannot be determined in this study. Meanwhile, life expectancy and quality-of-life assessment in this patient group is complex in the acute setting. Therefore, frailty and age should not prohibit immediate invasive management, as pPCI also in the very elderly (>80 years) improves prognosis.
Real-world outcome from ST elevation myocardial infarction in the very elderly before and after the introduction of a 24/7 primary percutaneous coronary intervention service.
We found that 30-day mortality in patients with STEMI with EMS-witnessed OHCA was similar to invasively treated patients with STEMI without OHCA, which stresses that advanced life support can safely be performed “en route” to a pPCI center. Consequently, optimal STEMI networks should provide physician-manned prehospital ground or helicopter units that can intubate and infuse antiarrhythmic, inotropic, and vasopressor agents during transfer. Beyond the well-known survival benefits of reducing reperfusion delays in patients with STEMI,
The Primary Coronary Angioplasty vs. Thrombolysis Group Does time matter? A pooled analysis of randomized clinical trials comparing primary percutaneous coronary intervention and in-hospital fibrinolysis in acute myocardial infarction patients.
our results illustrate how the absolutely greatest potential in survival improvement for patients with ACS lies within the first days after admission. In summary, all transfer resources in STEMI networks should therefore be considered in any patient with STEMI.
Although mortality risk in patients with STEMI and UAP was attenuated after 30 days, NSTEMI presenters maintained a ≈50% surplus of adjusted mortality hazard during the following 5 years. This is in line with findings from the Global Registry of Acute Coronary Events.
The ≈40% prevalence of patients with NSTEMI being noninvasively managed is very similar to results from the second Euro Heart Survey on ACS conducted during 2004 in 32 countries,
The second Euro Heart Survey on acute coronary syndromes: characteristics, treatment, and outcome of patients with ACS in Europe and the Mediterranean Basin in 2004.
suggesting that this proportion has not changed over time. It has been suggested that CAG use is concentrated in the lowest-risk group of patients with NSTE-ACS, which could inflate the described benefits of revascularization.
We found patients who were noninvasively managed to be older, with more known coronary artery disease, and prehospital tachycardia. Despite these associations, noninvasive management remained an independent predictor of short- and long-term mortality, adjusted for age, gender, and co-morbidity. This indicates that increased invasive management of patients with NSTE-ACS improves short- and long-term outcome, regardless of age.
Use of invasive strategy in non-ST-segment elevation myocardial infarction is a major determinant of improved long-term survival: FAST-MI (French Registry of Acute Coronary Syndrome).
Immediate coronary angiography in survivors of OHCA with or without ST-segment elevation appears to improve survival, as approximately 70% of patients with OHCA have coronary artery disease,
Immediate percutaneous coronary intervention is associated with better survival after out-of-hospital cardiac arrest: insights from the PROCAT (Parisian Region Out of hospital Cardiac ArresT) registry.
Patients with stroke and heart failure had an extreme mortality hazard in the first days after EMS admission. Time is therefore of the essence also in these patients; however, structured treatment networks with efficient triage alike those for patients with STEMI have only started to appear for patients with acute heart failure in need of cardiac intensive care unit admission and bridging invasive left ventricular support.
It is well known that intravenous administration of alteplase in patients with acute ischemic stroke has a number needed to treat for favorable outcome that rapidly decreases from 2 after the first 90 minutes to 14 after 3 to 4.5 hours.
Hypertension and dyslipidemia are treated by general practitioners, and the respective ICD diagnoses are therefore not registered in the hospital sector–based central patient registries, applied in this study. Therefore, these variables are likely underreported and their predictive strength is not conferred in univariate and multivariate analyses. Conversely, the remaining covariates have therefore strong reliability as they are based on in-hospital diagnostic and procedure codes whereas the prehospital vital parameters were reported in ≈90% of cases. Some of the CV discharge diagnosis categories are small in numbers and the correspondent hazard ratios are therefore less stable with large confidence intervals. Still, the following previous studies support the external validity of our results: Rawshani et al found that in elderly (≥65 years of age) patients dialing for EMS for chest pain, 1-year all-cause mortality was 18%.
Correspondingly, we found a very similar 17.1% 1-year mortality incidence in patients with similar age demographics for the diagnoses likely to lead to chest pain (i.e., STEMI, NSTEMI, UAP, ACS rule-out, atrial fibrillation, heart failure, and “other CV” [e.g., tachycardia or aortic stenosis]). Furthermore, the 30-day survival after OHCA was 10.7% in a recent large Swedish cohort and very similar to our rate of 11.6%.
Dr. Schoos has received a 3-year scholarship as part of a PhD program at Rigshospitalet, University of Copenhagen, which had no role in the preparation of this manuscript. The authors declare no support from any organization for the submitted work, no financial relationships with any organizations that might have an interest in the submitted work in the previous 3 years, and no other relationships or activities that could appear to have influenced the submitted work.
References
Schmidt M.
Jacobsen J.B.
Lash T.L.
Bøtker H.E.
Sørensen H.T.
25 year trends in first time hospitalisation for acute myocardial infarction, subsequent short and long term mortality, and the prognostic impact of sex and comorbidity: a Danish nationwide cohort study.
Pre-hospital diagnosis and transfer of patients with acute myocardial infarction: a decade long experience from one of Europe's largest STEMI networks.
The validity of the diagnosis of acute myocardial infarction in routine statistics: a comparison of mortality and hospital discharge data with the Danish MONICA registry.
The Primary Coronary Angioplasty vs. Thrombolysis Group
Does time matter? A pooled analysis of randomized clinical trials comparing primary percutaneous coronary intervention and in-hospital fibrinolysis in acute myocardial infarction patients.
Developing an analytical tool for evaluating EMS system design changes and their impact on cardiac arrest outcomes: combining geographic information systems with register data on survival rates.
Real-world outcome from ST elevation myocardial infarction in the very elderly before and after the introduction of a 24/7 primary percutaneous coronary intervention service.
The second Euro Heart Survey on acute coronary syndromes: characteristics, treatment, and outcome of patients with ACS in Europe and the Mediterranean Basin in 2004.
Use of invasive strategy in non-ST-segment elevation myocardial infarction is a major determinant of improved long-term survival: FAST-MI (French Registry of Acute Coronary Syndrome).
Immediate percutaneous coronary intervention is associated with better survival after out-of-hospital cardiac arrest: insights from the PROCAT (Parisian Region Out of hospital Cardiac ArresT) registry.
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