Does the Canadian Syncope Risk Score Work Outside of Canada?

June 1, 2022

Written by Jonathan Brewer

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This external validation of the Canadian Syncope Risk Score (CSRS) demonstrated good performance in identifying patients at low risk for serious outcome and was superior to the preexisting European OESIL score.

Why does this matter?
The CSRS has been validated within 9 Canadian EDs and was found to be superior when compared with multiple other current tools. This was the first large international validation that included the United States, Australia, New Zealand, and 5 European countries and compared the CSRS to a previously validated European syncope risk stratification score (OESIL score).

Canadians to the Rescue
This was a large, prospective cohort study that included 2,283 patients ≥ 40 years that presented to the ED within 12 hours of syncope. The primary outcomes of the study were a composite of serious clinical events (i.e. myocardial infarction, life-threatening arrhythmia, etc.) and procedural interventions for treatment of syncope (i.e. pacemaker or ICD) within 30 days, along with a clinical-only outcome that did not include procedural interventions.

Among this large cohort, 1,235 (54%) were hospitalized; 60% were classified as low or very low risk by CSRS in comparison to 48% by OESIL. Of these patients, only 0.6% had adverse clinical-only outcomes at 30 days with the CSRS versus 1.5% with the OESIL score. Prognostic performance of the CSRS was good for both 30-day composite outcomes and better when compared with the OESIL score (AUC, 0.85 vs 0.74 and 0.80 vs 0.69, respectively).

Clinician classification of syncope (a subjective ‘gestalt’) was just one component of the score, but this single component was almost as accurate as the full CSRS score. In fact, when a simplified model was utilized that only included the clinician classification of syncope (cardiac vs vasovagal vs neither), similar discrimination as the CSRS for the primary composite outcome was found (AUC, 0.83).

Overall, this score seems to show good performance in the identification of patients at low risk for serious outcomes and may help us identify candidates for discharge from the ED.

Editor’s note: I actually felt better about the CSRS before I read this study. The CSRS missed some patients classified as very low and low risk in this external validation study. I’m with the authors in their final conclusion, “The clinical utility of the CSRS remains uncertain.” ~Clay Smith

Source
International Validation of the Canadian Syncope Risk Score : A Cohort Study. Ann Intern Med. 2022 Apr 26. doi: 10.7326/M21-2313. Online ahead of print.