Quantity and Quality of Healthcare Professionals, Transfer Delay and In-hospital Mortality Among ST-Segment Elevation Myocardial Infarction: A Mixed-Method Cross-Sectional Study of 89 Emergency Medical Stations in China

Effect of the "door-to-balloon" time on the results of treatment of patients with ST-segment elevation myocardial infarction, depending on the duration of the pre-hospital delay

Aim    To analyze the effect of the door-to-balloon time on treatment outcomes in patients with acute ST-segment elevation myocardial infarction (STEMI) depending on the duration of pre-hospital delay.Material ad methods    The study used data of the hospital registry of percutaneous coronary interventions (PCI) in STEMI from 2006 through 2017. The analysis included 1333 patients. All patients were divided into two groups. The first group included 574 (43.1%) patients with the time from the pain syndrome onset to admission was ≤120 min. The second group consisted of 759 (56.9 %) patients with the time of pre-hospital delay exceeding 120 min. Results of the treatment were analyzed for each group depending on the door-to-balloon time, ≤60 min or >60 min.Results    In the group of patients with the prehospital delay less than 120 min and the door-to-balloon time ≤60 min vs. patients with the door-to-balloon time >60 min, the following was observed: decreased in-hospital mortality (1.3 % vs. 6.8 %, p=0.001), reduced incidence of major adverse cardiac effects (МАСЕ) (3.2 % vs. 8.3 %, p=0.008), and reduced incidence of the no-reflow phenomenon (3.9 % vs. 9.4 %, p=0.007). Also, immediate angiographic success of PCI was more frequently achieved in these patents (94.5 % vs. 87.5 %, p=0.003). In addition, in the group with the prehospital delay ≤120 min and the door-to-balloon time ≤60 min, a higher ejection fraction was noted at discharge from the hospital (48 [43; 51] % vs. 46 [42; 51] %, р=0.038). Comparison of treatment outcomes between the groups with different door-to-balloon time (≤60 min or >60 min) and a prehospital delay >120 min did not show any significant intergroup differences. According to a multivariate analysis, the door-to-balloon time ≤60 min did not predict in-hospital mortality. There was a strong correlation between the time of prehospital delay and the total time of myocardial ischemia (r=0.87; р<0.001) while the correlation between the door-to-balloon time and the total time of myocardial ischemia was moderate (r=0.41; р<0.001). At the same time, there was no correlation between the time of prehospital delay and the door-to-balloon time.Conclusion    In STEMI patients with a prehospital delay less than 120 min from the pain syndrome onset, a decrease in the door-to-balloon time was associated with better outcome of the hospital treatment. When the duration of prehospital delay was more than 120 min, a decrease in door-to-balloon time did not influence the treatment outcome. The time of prehospital delay strongly correlated with the total time of myocardial ischemia.

Urban-suburb disparities in pre-hospital emergency medical resources and response time among patients with out-of-hospital cardiac arrest: A mixed-method cross-sectional study

Aim

To investigate (1) the association between pre-hospital emergency medical resources and pre-hospital emergency medical system (EMS) response time among patients with Out-of-hospital cardiac arrest (OHCA); (2) whether the association differs between urban and suburbs.

Methods

Densities of ambulances and physicians were independent variables, respectively. Pre-hospital emergency medical system response time was dependent variable. Multivariate linear regression was used to investigate the roles of ambulance density and physician density in pre-hospital EMS response time. Qualitative data were collected and analyzed to explore reasons for the disparities in pre-hospital resources between urban areas and suburbs.

Results

Ambulance density and physician density were both negatively associated with call to ambulance dispatch time, with odds ratios (ORs) 0.98 (95% confidence interval [CI] 0.96-0.99; P = 0.001) and 0.97 (95% CI; 0.93-0.99; P < 0.001), respectively. ORs of ambulance density and physician density in association with total response time were 0.99 (95% CI: 0.97-0.99; P = 0.013) and 0.90 (95% CI: 0.86-0.99; P = 0.048). The effect of ambulance density on call to ambulance dispatch time in urban areas was 14% smaller than that in suburb areas and that on total response time in urban areas was 3% smaller than the effect in suburbs. Similar effects were identified for physician density on urban-suburb disparities in call to ambulance dispatch time and total response time. The main reasons summarized from stakeholders for a lack of physicians and ambulances in suburbs included low income, poor personal incentive mechanisms, and inequality in financial distribution of the healthcare system.

Conclusion

Improving pre-hospital emergency medical resources allocation can reduce system delay and narrow urban-suburb disparity in EMS response time for OHCA patients.