The role of coronary angiography in out-of-hospital cardiac arrest patients in the absence of ST-segment elevation: A literature review

Variation in practice for out-of-hospital cardiac arrest treated with percutaneous coronary intervention in England and Wales

OBJECTIVES

We assessed the association between total center volume, operator volume, and out-of-hospital cardiac arrest (OHCA) percutaneous coronary intervention (PCI) volume.

BACKGROUND

Variations between OHCA PCI volume, hospital total PCI, and primary PCI volume are not well studied and are unlikely to be clinically justifiable.

METHODS

Patients undergoing PCI for the acute coronary syndrome (ACS) between January 1, 2014, and March 31, 2019, in England and Wales were grouped as OHCA PCI and non-OHCA PCI. Spearman's correlation was used to determine the degree of correlation between each hospital PCI volume and OHCA PCI volume.

RESULTS

Out of 250,088 PCI procedures undertaken for ACS, 12,016 (4.8%) were performed for OHCA, and 238,072 (95.2%) were non-OHCA PCI procedures. The OHCA PCI group were younger [mean age (SD) 63.2 (12.3) and 65.6 (12.5, p < 0.001)], less likely to be female (20.2% vs. 26.9%, p < 0.001) or Black, Asian, and Minority Ethnicity (11.5% vs. 14.8%, p < 0.001) compared to the non-OHCA PCI group. Although there was a degree of correlation between total PCI and OHCA PCI, there was wide variation for both ACS cohort (Spearman correlation R²  = 0.50) and total PCI volume (Spearman correlation R²  = 0.60). Furthermore, the correlation between primary PCI volume and OHCA PCI within centers was weak (R²  = 0.10). Similarly, wide variations between operator PCI volume and OHCA PCI volume were observed.

CONCLUSION

These national data demonstrate wide variation in the practice of OHCA PCI both between centers and individuals. These variations are not expected according to clinical factors and require further investigation.

Cardiac arrest centres: what, who, when, and where?

PURPOSE OF REVIEW

Cardiac arrest centres (CACs) may play a key role in providing postresuscitation care, thereby improving outcomes in out-of-hospital cardiac arrest (OHCA). There is no consensus on CAC definitions or the optimal CAC transport strategy despite advances in research. This review provides an updated overview of CACs, highlighting evidence gaps and future research directions.

RECENT FINDINGS

CAC definitions vary worldwide but often feature 24/7 percutaneous coronary intervention capability, targeted temperature management, neuroprognostication, intensive care, education, and research within a centralized, high-volume hospital. Significant evidence exists for benefits of CACs related to regionalization. A recent meta-analysis demonstrated clearly improved survival with favourable neurological outcome and survival among patients transported to CACs with conclusions robust to sensitivity analyses. However, scarce data exists regarding 'who', 'when', and 'where' for CAC transport strategies. Evidence for OHCA patients without ST elevation postresuscitation to be transported to CACs remains unclear. Preliminary evidence demonstrated greater benefit from CACs among patients with shockable rhythms. Randomized controlled trials should evaluate specific strategies, such as bypassing nearest hospitals and interhospital transfer.

SUMMARY

Real-world study designs evaluating CAC transport strategies are needed. OHCA patients with underlying culprit lesions, such as those with ST-elevation myocardial infarction (STEMI) or initial shockable rhythms, will likely benefit the most from CACs.

Validation of the CREST score for predicting circulatory-aetiology death in out-of-hospital cardiac arrest without STEMI

AIMS

The CREST tool was recently developed to stratify the risk of circulatory-aetiology death (CED) in out-of-hospital cardiac arrest (OHCA) patients without ST-elevation myocardial infarction (STEMI). We aimed to validate the CREST score using an external cohort and determine whether it could be improved by the addition of serum lactate on admission.

METHODS

The study involved the retrospective analysis of consecutive patients admitted to a single tertiary centre with OHCA of presumed cardiac origin over a 51-month period. The CREST score was calculated by attributing points to the following variables: Coronary artery disease (CAD), non-shockable Rhythm, Ejection fraction <30%, cardiogenic Shock at presentation and ischaemic Time ≥25 minutes. The primary endpoint was CED vs neurological aetiology death (NED) or survival.

RESULTS

Of 500 patients admitted with OHCA, 211 did not meet criteria for STEMI and were included. 115 patients died in hospital (71 NED, 44 CED). When analysed individually, CED was associated with all CREST variables other than a previous diagnosis of CAD. The CREST score accurately predicted CED with excellent discrimination (C-statistic 0.880, 95% CI 0.813-0.946) and calibration (Hosmer and Lemeshow P=0.948). Although an admission lactate ≥7 mmol/L also predicted CED, its addition to the CREST score (the C-AREST score) did not significantly improve the predictive ability (CS 0.885, 0.815-0.954, HS P=0.942, X² difference in -2 log likelihood =0.326, P=0.850).

CONCLUSION

Our study is the first to independently validate the CREST score for predicting CED in patients presenting with OHCA without STEMI. Addition of lactate on admission did not improve its predictive ability.

Timing of coronary angiography in patients following out-of-hospital cardiac arrest without ST-segment elevation: A systematic review and Meta-analysis of randomized trials

INTRODUCTION

Out-of-hospital cardiac arrest (OHCA) has a poor prognosis. The timing and role of early coronary angiography (CAG) in OHCA patients without ST elevation remains unclear.

OBJECTIVE

We performed a meta-analysis of randomized controlled trials (RCTs) that compared early CAG to delayed CAG in OHCA patients without ST elevation.

METHODS

We searched PubMed, Cochrane, and ClinicalTrials.gov databases (from inception to September 2021) for studies comparing early CAG to delayed CAG in OHCA patients without ST elevation. We used a random-effect model to calculate relative ratio (RR) with 95% confidence interval (CI). The primary outcome was all-cause mortality at 30 days. Secondary outcomes included neurological status with cerebral performance category ≤2 (CPC) and the rate of percutaneous coronary intervention (PCI) following CAG.

RESULTS

A total of 6 RCTs including 1822 patients, of whom 895 underwent early CAG, and 927 underwent delayed CAG, were included in this meta-analysis. There was no statistically significant difference between the 2 groups in terms of 30-day all-cause mortality (Relative risk [RR] 1.06; 95%CI 0.94-1.20; P = 0.32; I² = 13%), neurological status (CPC ≤2) (RR 1.01; 95%CI 0.90-1.13; P = 0.85, I² = 37%), and rates of PCI following CAG (RR 1.08; 95%CI 0.84-1.39; P = 0.56; I² = 49%).

CONCLUSION

In patients suffering OHCA without ST-elevation, early CAG is not associated with reduced 30-day mortality when compared to patients who underwent delayed CAG. Given our meta-analysis results including multiple trials that have not shown a benefit, it is likely that updated guidelines will not support early angiography in patients suffering OHCA without ST-elevation.