Syncope: cardiac biomarkers independently predict 30-day outcomes

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Takeaway

  • In patients with syncope presenting to the emergency department (ED), high-sensitivity troponin (hsTnT) and natriuretic peptide (NT-proBNP) were independent predictors of death or serious cardiac events within 30 days.
  • Low values may allow for safe discharge.

Why this matters

  • Prediction tools are lacking to help disposition decisions in syncope for patients aged ≥60 years.

Key results

  • 77.74% of patients were admitted.
  • Primary outcome occurred in 10.8% (367 patients). 
  • Both biomarkers were independent predictors, without significant interaction with each other.
  • Adjusted absolute risk with (95% CIs):
    • hsTnT ≤5 ng/L: 4% (3%-5%).
    • hsTnT >50 ng/L: 29% (26%-33%). 
    • NT-proBNP ≤125 ng/L: 4% (4%-5%).
    • NT-proBNP >2000 ng/L: 29% (25%-32%).
  • Similar findings upon sensitivity analyses.
  • When omitting events occurring during index visit: 
    • hsTnT ≤5 ng/L:
      • absolute 30-day risk, 0.02;
      • negative predictive value (NPV), 0.985 (95% CI, 0.973-0.993).
    • NT-proBNP ≤125 ng/L:
      • absolute 30-day risk, 0.02;
      • NPV, 0.985 (95% CI, 0.976-0.991).

Study design

  • Planned secondary analysis of prospective multicenter observational SRS study of patients presenting to 11 US EDs after syncope or near-syncope (n=3392).
  • Outcome: combined 30-day all-cause mortality and serious cardiac events.
  • Funding: NIH.

Limitations

  • Older cohort.
  • Single blood draw.