Variation in outcome of hospitalised patients with out-of-hospital cardiac arrest from acute coronary syndrome: a cohort study

Abstract

Background Each year, approximately 30,000 people have an out-of-hospital cardiac arrest (OHCA) that is treated by UK ambulance services. Across all cases of OHCA, survival to hospital discharge is less than 10%. Acute coronary syndrome (ACS) is a common cause of OHCA. Objectives To explore factors that influence survival in patients who initially survive an OHCA attributable to ACS. Data source Data collected by the Myocardial Ischaemia National Audit Project (MINAP) between 2003 and 2015. Participants Adult patients who had a first OHCA attributable to ACS and who were successfully resuscitated and admitted to hospital. Main outcome measures Hospital mortality, neurological outcome at hospital discharge, and time to all-cause mortality. Methods We undertook a cohort study using data from the MINAP registry. MINAP is a national audit that collects data on patients admitted to English, Welsh and Northern Irish hospitals with myocardial ischaemia. From the data set, we identified patients who had an OHCA. We used imputation to address data missingness across the data set. We analysed data using multilevel logistic regression to identify modifiable and non-modifiable factors that affect outcome. Results Between 2003 and 2015, 1,127,140 patient cases were included in the MINAP data set. Of these, 17,604 OHCA cases met the study inclusion criteria. Overall hospital survival was 71.3%. Across hospitals with at least 60 cases, hospital survival ranged from 34% to 89% (median 71.4%, interquartile range 60.7–76.9%). Modelling, which adjusted for patient and treatment characteristics, could account for only 36.1% of this variability. For the primary outcome, the key modifiable factors associated with reduced mortality were reperfusion treatment [primary percutaneous coronary intervention (pPCI) or thrombolysis] and admission under a cardiologist. Admission to a high-volume cardiac arrest hospital did not influence survival. Sensitivity analyses showed that reperfusion was associated with reduced mortality among patients with a ST elevation myocardial infarction (STEMI), but there was no evidence of a reduction in mortality in patients who did not present with a STEMI. Limitations This was an observational study, such that unmeasured confounders may have influenced study findings. Differences in case identification processes at hospitals may contribute to an ascertainment bias. Conclusions In OHCA patients who have had a cardiac arrest attributable to ACS, there is evidence of variability in survival between hospitals, which cannot be fully explained by variables captured in the MINAP data set. Our findings provide some support for the current practice of transferring resuscitated patients with a STEMI to a hospital that can deliver pPCI. In contrast, it may be reasonable to transfer patients without a STEMI to the nearest appropriate hospital. Future work There is a need for clinical trials to examine the clinical effectiveness and cost-effectiveness of invasive reperfusion strategies in resuscitated OHCA patients of cardiac cause who have not had a STEMI. Funding The National Institute for Health Research Health Services and Delivery Research programme.

Prognostic Significance of Ventricular Arrhythmias in 13 444 Patients With Acute Coronary Syndrome: A Retrospective Cohort Study Based on Routine Clinical Data (NIHR Health Informatics Collaborative VA‐ACS Study)

“…Because of the limitations of ICD‐10 coding, we were unable to accurately differentiate shockable (VT or VF) versus nonshockable (bradyarrhythmia or pulseless electrical activity) rhythms during CA. However, previous data from a similar cohort suggested that 89.6% of patients who have out‐of‐hospital CA in the context of ACS have VT or VF as the presenting rhythm, 1 which provide the basis for our assumption that the vast majority of CAs at the time of ACS in our study are attributed to VAs.…”

“…A minority of acute coronary syndrome (ACS) patients who survive to hospital admission are associated with ventricular arrhythmia (VA), a subset of which cause cardiac arrest (CA). 1 Acute myocardial ischemia leads to a series of progressive electrophysiological changes at the cellular level that predispose to VA, 2 although it remains unclear why only a minority of patients with ACS develop VA, whereas the vast majority do not. 3 …”

The effect of prehospital critical care on survival following out-of-hospital cardiac arrest: A prospective observational study

“…Finally, transfer to a cardiac arrest centre is thought to improve survival following OHCA but a potential effect size has not been clearly defined. 28,29 In our study, bypass of the nearest hospital in favour of a cardiac centre was a relatively common prehospital critical care intervention. However, the receiving hospital for patients in the ALS group was a cardiac arrest centre in nearly half of the patients transferred, thereby diluting a potentially small to moderate effect of prehospital critical care.…”

Short- and Long-term Myocardial Infarction Survival Rate According to the Type of Drugs Prescribed at the Time of Discharge: A Study Using Iran National Registry Data

“…Nevertheless, there is much variability in longterm prognosis for patients with acute coronary syndrome who survive to be discharged from the hospital. 7,8 Some studies have been conducted in Iran to determine the survival rate in different provinces, but none of them has been population-based, considering the whole country using MI registry data and type of drugs prescribed at the time of discharge. Therefore, this retrospective cohort study was designed to estimate short-and long-term survival rates in MI patients and their contributing factors and medications prescribed at the time of discharge in patients with the first attack of MI in the Islamic Republic of Iran.…”