EBQ:San Francisco Syncope Rule

Under Review Journal Club Article

Quinn J. et al.. "Prospective validation of the San Francisco Syncope Rule to predict patients with serious outcomes". Ann Emerg Med. 2006. 31(26):2992-6.
PubMed Full text PDF

Clinical Question

Can the San Francisco Syncope Rule be used in clinical practice to risk stratify patients presenting with syncope?

Conclusion

• The San Francisco Syncope Rule demonstrated to be highly sensitive (98% sensitivity, 95% CI 89-100%) but not very specific (56%, 95% CI 52-60%) for predicting serious outcomes.

Major Points

Criteria (CHESS Pneumonic)

• CHF History
• Hct < 30%
• ECG Abnormality
• SOB history
• SBP < 90mmHg at triage

The rule is positive if any of the above apply to the patient.

Study Design

• A prospective cohort study
• N=791
• Consecutive patients with syncope or near syncope presenting to an emergency department of a large, urban teaching hospital were identified and enrolled from July 15, 2002 to August 31, 2004
• Physicians prospectively applied the San Francisco Syncope Rule
  • Patient follow up performed to determine if the patient suffered a predefined serious outcome within 30 days of their ED visit
  • Physicians completed a short Web-based form and enrolled patients after their assessment
  • Study investigators reviewed all data forms in order to ensure the correct interpretation of the rule
• 30 day follow-up completed after patients' index ED visit to determine short-term outcomes that would require admission
  • Short-term serious outcomes defined as:
    • Death
    • Myocardial Infarction
    • Arrhythmia
    • Pulmonary Embolism
    • Stoke
    • Subarachnoid Hemorrhage
    • Significant Hemorrhage or Anemia Requiring Transfusion
    • Procedural intervention to treat a related cause of syncope or any condition causing or likely to cause a return ED visit
    • Hospitalization for a related event

Population

Patient Demographics

• 364 men, 427 females
• Mean age: 61
• Admitted: 469
• Patients with serious outcomes after ED visit: 54 (6.8%)
  • Death: 3
  • Arrhythmia: 23
  • Myocardial Infarction: 11
  • Valvular Heart Disease: 1
  • Significant Hemorrhage: 7
  • TIA/Stroke: 3
  • Sepsis: 3
  • Admission after ED Discharge : 3

Inclusion Criteria

• Consecutive patients presenting with syncope or near syncope without any of the predefined exclusion criteria

Exclusion Criteria

• Trauma-related loss of consciousness
• Alcohol-related loss of consciousness
• Drug-related loss of consciousness
• Definite seizure

Outcomes

• 30 day follow-up after the patients' index ED visit to determine serious short-term outcomes
• Serious short-term outcomes defined as: death, myocardial infarction, arrhythmia, pulmonary embolism, stroke, subarachnoid hemorrhage, significant hemorrhage or anemia requiring transfusion, procedural intervention to treat a related cause of syncope or any condition likely to cause a return ED visit, and hospitalization for a related event

Primary Outcome

• Patients with serious outcomes after ED visit: 54 (6.8%)

Performance of the San Francisco Syncope Rule in the validation cohort

Decision Rule	Yes	No
Rule Positive	52	290
Rule Negative	1	370

• Sensitivity 98% (95% CI 89% to 100%)
• Specificity 56% (95% CI 52% to 60%)
• Negative Predictive Value 99.7% (95% CI 98% to 100%)
• Positive Predictive Value 15% (95% CI 12% to 20%)
• Death: 3
• Arrhythmia: 23
• Myocardial Infarction: 11
• Valvular Heart Disease: 1
• Significant Hemorrhage: 7
• TIA/Stroke: 3
• Sepsis: 3
• Admission after ED discharge: 3

Secondary Outcomes

• Physicians accurately interpreted the rule 95% of the time
  • Physicians felt comfortable using the rule in 79% of the cases
  • Physicians felt neutral using the rule in 15% of cases
  • Physicians felt uncomfortable using the rule in 6% of cases
• The San Francisco Syncope Rule would have classified 52% of the patients as high risk
  • Using the rule potentially would have decreased overall admissions by 7%
  • Applying the rule to only the 453 patients admitted might have decreased admissions by 24%

Criticisms & Further Discussion

• Patient’s from only one hospital enrolled in the study
• Validation study is performed at the same center used to derive the original rule

Funding

• A career development grant from the National Institutes of Health available to Dr. James Quinn, MD, MS, primary investigator of the study