Elsevier

American Heart Journal

Volume 234, April 2021, Pages 31-41
American Heart Journal

Curriculum in Cardiology
Out-of-hospital cardiac arrest: A systematic review of current risk scores to predict survival

https://doi.org/10.1016/j.ahj.2020.12.011Get rights and content

Importance

The arrest and the post-arrest period are an incredibly emotionally traumatic time for family and friends of the affected individual. There is a need to assess prognosis early in the patient pathway to offer objective, realistic and non-emotive information to the next-of-kin regarding the likelihood of survival.

Objective

To present a systematic review of the clinical risk scores available to assess patients on admission following out-of-hospital cardiac arrest (OHCA) which can predict in-hospital mortality.

Evidence review

A systematic search of online databases Embase, MEDLINE and Cochrane Central Register of Controlled Trials was conducted up until 20th November 2020.

Findings

Out of 1,817 initial articles, we identified a total of 28 scoring systems, with 11 of the scores predicting mortality following OHCA included in this review. The majority of the scores included arrest characteristics (initial rhythm and time to return of spontaneous circulation) as prognostic indicators. Out of these, the 3 most clinically-useful scores, namely those which are easy-to-use, comprise of commonly available parameters and measurements, and which have high predictive value are the OHCA, NULL-PLEASE, and rCAST scores, which appear to perform similarly. Of these, the NULL-PLEASE score is the easiest to calculate and has also been externally validated.

Conclusions

Clinicians should be aware of these risk scores, which can be used to provide objective, nonemotive and reproducible information to the next-of-kin on the likely prognosis following OHCA. However, in isolation, these scores should not form the basis for clinical decision-making.

Section snippets

Methods

We performed a systematic review of available risk scores to predict outcome in patients presenting with OHCA. This is reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.7 For each score, we examined the details of original development and any subsequent validation cohorts, comparing the scores in terms of ease of use, ability to predict survival, and availability of independent external validation.

Results

The systematic search identified 1,817 articles, from which 16 articles were included in this review (Figure 1). A total of 28 scoring systems were identified which assessed patients on admission, 11 of the scores included predicted mortality following OHCA, 14 predicted neurological outcome and 3 scores, not specific to the OHCA-population including the GRACE8 (which was developed for use in mortality prediction in acute coronary syndrome), the APACHE II9 and the SOFA10 scores (used for

Discussion

A useful scoring system should provide high sensitivity (to predict patients with poor prognosis) and high specificity (to ensure all patients with potentially good outcomes are treated).28,29 This systematic review has identified many risk scores from the current literature with variable predictive ability in this high-risk cohort of patients which reflects firstly, the emphasis on having an admission prognosis prediction and secondly, the difficulty in providing a “perfect” risk prediction

Limitations

Publication bias is one of the main limitations of this review as studies with smaller impact may not have been published. The varied presentation and heterogenicity of patients presenting with OHCA within each paper is not always available and may have an impact on the predictive value provided. There has been no formal head-to-head comparison of the various risk scores although this could be possible with pooling analysis using individual patient-level data. Outcome following OHCA may vary by

Conclusion

There are a number of risk scores available to determine the likelihood of survival following OHCA. The OHCA, NULL-PLEASE and rCAST scores appear most favorable and perform similarly in predicting survival, and of these, we recommend the NULL-PLEASE score as the one that is easiest to calculate and which has been externally validated. Risk scores should be used by medical professionals to provide objective, nonemotive and reproducible information to next-of-kin, but in isolation, should not

Patient and public involvement

There was no patient or public involvement in this project.

Ethics

As this was a systematic review not involving direct patient care or data, ethical approval was not sought.

Disclosures

The authors have no disclosures to make in respect of this manuscript.

CRediT authorship contribution statement

Ying X. GUE: Conceptualization, Methodology, Data curation, Writing - original draft, Visualization. Krishma ADATIA: Methodology, Investigation. Rahim KANJI: Methodology, Investigation. Tatjana POTPARA: Conceptualization, Methodology, Validation. Gregory Y.H. LIP: Conceptualization, Methodology, Validation. Diana A. GOROG: Conceptualization, Methodology, Validation, Writing - review & editing, Visualization, Supervision.

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