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This study, conducted over two time periods, aimed to evaluate the effectiveness of the diffusion of data, implementation of correctives measures and updated protocols in reducing time to reperfusion in acute myocardial infarction (AMI) management in the out‐of‐hospital setting. Mean (SD) time to hospital admission and to arterial puncture improved (58 (13) vs 67 (18) min, p=0.03; and 82 (16) vs 95 (29) min, p=0.02). The study, performed according to quality control programme methodology, showed that the chronology of AMI management could be improved by appropriate interventions and monitoring of intervention times.
The reduction of early and long‐term mortality of patients with acute myocardial infarction (AMI) is related to the time to reperfusion.1,2 Percutaneous coronary intervention has become the preferred approach for treating ST elevation AMI,3,4 and the time to balloon has become a challenge for all care providers involved in the pathway of patients presenting with AMI.5,6 The French emergency medical services (EMS) system is based on mobile intensive care units (MICU) with emergency physicians on board the ambulance, who provide on‐scene diagnosis of AMI and start reperfusion treatments.7 To improve the pre‐hospital management of AMI, a regional registry was implemented in the Paris area. The aim of this study is to evaluate the efficiency of the registry in improving AMI management, as part of a quality control programme.
The e‐Must Registry is a prospective, descriptive study, which was conducted in our EMS department, covering an area of 290172 inhabitants during two, 1 year periods. Inclusion criteria were the presence of typical chest pain and an electrocardiogram (ECG) with ST elevation in two contiguous leads or new left bundle branch blockade. Reperfusion strategy was defined as the first treatment chosen to restore coronary reflow: pre‐hospital thrombolysis or primary angioplasty, up to the physician's discretion during the first 3 h and always primary angioplasty after 3 h. Data were collected on demographic characteristics, AMI location, possible complications, and reperfusion strategy. The different time intervals were recorded. The data collected during the year 2002 were analysed and the results were passed to all physicians and paramedics during a formal session, but also using an electronic mailing list.
Corrective strategies were defined as: systematic admission to the catheterisation laboratory; early request for catheterisation laboratory to avoid waiting for destination; early activation of catheterisation laboratory to ensure that the interventional cardiologist is ready when the patient arrives; choice of destinations in favour of the nearest catheterisation laboratory. A workgroup has been sorted out among the staff to work out on updated protocols in accordance with the cardiologists of our hospital and according to recent guidelines.8 These protocols were explained to all the teams and repeated training sessions and implemented. During these training sessions, the importance of early reperfusion in reducing myocardium damage was emphasised, and explained by simple messages such as “time saves muscle” or “golden hour”.
Throughout 2004, a new audit was carried out to evaluate the efficiency of interventions on delay to reperfusion. Entry criteria and methods remained strictly the same. The primary aim of the study was to compare the evolution of time intervals between the two periods. Results are reported as mean (SD) for continuous variables. Qualitative data are expressed as the percentage of patients. Statistical analysis was performed using a one‐way analysis of variance (ANOVA) for quantitative data and a χ2 test for qualitative data. Significance was defined as p<0.05.
Ninety‐eight patients were included: 56 patients during the first period and 42 patients during the second period. All the patients presenting inclusion criteria were enrolled. Characteristics of patients were similar in both groups (table 11).). The reperfusion strategy is shown in table 22.. The time to the call and the time to the dispatching strategy (before the MICU management) were similar in both groups: mean time from occurrence of chest pain to arrival of MICU was 227 (256) vs 203 (190) min, during period 1 and period 2, respectively.
The time from arrival of the medical team to hospital reperfusion for patients with primary angioplasty was significantly improved in group 2 vs group 1 (table 33).). The pre‐hospital management reduction cannot be related to the distances covered because the duration of transfer was similar: 11 (5) vs 9 (4) min (p=0.07). For patients who received pre‐hospital thrombolysis, time from arrival of the MICU to thrombolytic infusion was similar: 36 (16) min for group 1 vs 38 (21) min for group 2 (p=0.8).
This study, performed according to quality control programme methodology, demonstrated that chronology of AMI management could be improved by appropriate interventions and monitoring of intervention times. We note also that the mean (SD) time from arrival of the MICU to arterial puncture was reduced from 95 (29) to 82 (16) min (table 33),), which means that the process is now better managed and more predictable. The main corrective measures were to insist for a very early request for access to a catheterisation laboratory and also for direct admission to the catheter laboratory, which became systematic in period 2, bypassing admission to the ICU or emergency department. These measures helped to reduce the initial time spent upon arrival at the hospital and have been previously described in studies evaluating the whole pathway of AMI management.9
AMI - acute myocardial infarction
ECG - electrocardiogram
EMS - emergency medical services
MICU - mobile intensive care units
Competing interests: None declared