Point-of-Care Guides

Canadian Syncope Risk Score: A Validated Risk Stratification Tool

 

Am Fam Physician. 2021 Mar 15;103(6):375-376.

Author disclosure: No relevant financial affiliations.

Clinical Question

Which adults presenting to the emergency department with syncope should be admitted?

Evidence Summary

Syncope accounts for almost 1% of all emergency department visits.1 Although only approximately 10% of patients presenting with syncope have a serious underlying cardiac condition, nearly one-third are admitted to the hospital.1 Several clinical prediction rules have been developed to help physicians identify patients with syncope who are at higher risk of adverse outcomes and those for whom discharge without hospitalization may be reasonable.

The San Francisco Syncope Rule was originally derived from a cohort of 684 patients and consists of five risk factors: abnormal findings on an electrocardiogram, hematocrit less than 30%, history of congestive heart failure, reported shortness of breath, and systolic blood pressure less than 90 mm Hg. If any of these risk factors are present, the patient is considered at high risk of a serious outcome. A meta-analysis of 12 validation studies with 5,316 patients found that for predicting serious outcomes in those classified as high risk, the San Francisco Syncope Rule has a sensitivity of 87% (95% CI, 79% to 93%), specificity of 52% (95% CI, 43% to 62%), positive likelihood ratio of 1.8 (95% CI, 1.7 to 1.9), and negative likelihood ratio of 0.25 (95% CI, 0.20 to 0.31).2

The ROSE (risk stratification of syncope in the emergency department) rule was derived from a cohort of 529 patients and prospectively validated in a cohort of 550 patients. It consists of six risk factors: brain natriuretic peptide of 300 pg per mL (300 ng per L) or greater, hemoglobin level of 9 g per dL (90 g per L) or less, bradycardia, chest pain, abnormal electrocardiogram finding (bradycardia of 50 beats per minute or less or Q wave present in a lead other than lead III), oxygen saturation of 94% or less, and the presence of fecal occult blood. Admission is recommended if any of these risk factors are present. The ROSE rule has a sensitivity of 87% (95% CI, 73% to 96%), specificity of 66% (95% CI, 61% to 70%), positive likelihood ratio of 2.5 (95% CI, 2.1 to 3.0), and a negative likelihood ratio of 0.20 (95% CI, 0.09 to 0.45).3

The Canadian Syncope Risk Score (Table 14,5) was initially derived from a prospective multi-center study involving six large Canadian academic emergency departments and 4,030 adult patients.4 Patients were excluded if they had immediate postsyncopal complications (prolonged loss of consciousness, altered mental status, seizure, or major trauma), a language barrier affecting the ability to obtain a detailed history, or a serious outcome identified during the initial emergency department visit. Patients were followed for 30 days to assess for serious outcomes. The Canadian Syncope Risk Score includes patient history, electrocardiogram findings, clinical impression, and troponin testing. The probability of a serious outcome was estimated at less than 1% in the low-risk and very low-risk groups and more than 12% in the high-risk and very high-risk groups.4

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TABLE 1.

Canadian Syncope Risk Score for Estimating Risk of Serious Outcomes Within 30 Days

CategoryPoints

Clinical evaluation

Predisposition to vasovagal symptoms

−1

History of heart disease

1

Any systolic blood pressure measurements < 90 mm Hg or > 180 mm Hg

2

Investigations

Elevated troponin level (> 99th percentile of the normal population)

2

Abnormal QRS axis (< −30 degrees or > 100 degrees)

1

QRS duration > 130 ms

1

Corrected QT interval > 480 ms

2

Diagnosis in emergency department

Vasovagal syncope

−2

Cardiac syncope

2

Total:

Risk level

Total score

Serious outcomes5


Very low

≤ −2

0.2%

Low

−1 to 0

0.7%

Medium

1 to 3

8%

High

4 to 5

19%

Very high

6

51%


Note: Serious outcomes include death, cardiac arrhythmia, structural heart disease, other cardiac event, pulmonary embolism, and gastrointestinal bleeding or other hemorrhage.

Adapted with permission from Thiruganasambandamoorthy V, Kwong K, Wells GA, et al. Development of the Canadian Syncope Risk Score to predict serious adverse events after emergency department assessment of syncope. CMAJ. 2016;188(12):e296, with additional information from reference 5.

TABLE 1.

Canadian Syncope Risk Score for Estimating Risk of Serious Outcomes Within 30 Days

CategoryPoints

Clinical evaluation

Predisposition to vasovagal symptoms

−1

History of heart disease

1

Any systolic blood pressure measurements < 90 mm Hg or > 180 mm Hg

2

Investigations

Elevated troponin level (> 99th percentile of the normal population)

2

Abnormal QRS axis (< −30 degrees or > 100 degrees)

1

QRS duration > 130 ms

1

Corrected QT interval > 480 ms

2

Diagnosis in emergency department

Vasovagal syncope

−2

Cardiac syncope

2

Total:

Risk level

Total score

Serious outcomes5


Very low

≤ −2

0.2%

Low

−1 to 0

0.7%

Medium

1 to 3

8%

High

4 to 5

19%

Very high

6

51%


Note: Serious outcomes include death, cardiac arrhythmia, structural heart disease, other cardiac event,

Address correspondence to Aaron Saguil, MD, MPH, at aaron.saguil@usuhs.edu. Reprints are not available from the authors.

Author disclosure: No relevant financial affiliations.

References

show all references

1. Sun BC, Emond JA, Camargo CA Jr. Characteristics and admission patterns of patients presenting with syncope to U.S. emergency departments, 1992–2000. Acad Emerg Med. 2004;11(10):1029–1034....

2. Saccilotto RT, Nickel CH, Bucher HC, et al. San Francisco Syncope Rule to predict short-term serious outcomes: a systematic review. CMAJ. 2011;183(15):E1116–E1126.

3. Reed MJ, Newby DE, Coull AJ, et al. The ROSE (risk stratification of syncope in the emergency department) study. J Am Coll Cardiol. 2010;55(8):713–721.

4. Thiruganasambandamoorthy V, Kwong K, Wells GA, et al. Development of the Canadian Syncope Risk Score to predict serious adverse events after emergency department assessment of syncope. CMAJ. 2016;188(12):E289–E298.

5. Thiruganasambandamoorthy V, Sivilotti MLA, Le Sage N, et al. Multi-center emergency department validation of the Canadian Syncope Risk Score. JAMA Intern Med. 2020;180(5):737–744.

This guide is one in a series that offers evidence-based tools to assist family physicians in improving their decision-making at the point of care.

This series is coordinated by Mark H. Ebell, MD, MS, deputy editor for evidence-based medicine.

A collection of Point-of-Care Guides published in AFP is available at https://www.aafp.org/afp/poc.

 

 

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