LAUSR

While high-sensitivity cardiac troponin (hs-cTn) and B-Type natriuretic peptide (BNP) have been assessed separately for the diagnosis and risk-stratification of patients with syncope, their combined accuracy is unknown. We assessed the diagnostic and prognostic accuracy of the combination of hs-cTnI and BNP in a prospective international multicenter study enrolling patients 40 years and older presenting with syncope to the emergency department (ED). Hs-cTnI (Architect) and BNP (Architect) concentrations were measured in a blinded fashion. Cardiac syncope, as adjudicated by two independent physicians using all available clinical information including one year follow-up, was the diagnostic endpoint. MACE were defined as death, resuscitation, life-threatening arrhythmia, implantation of a pacemaker or implantable cardioverter defibrillator (ICD), acute myocardial infarction, pulmonary embolism, stroke/transient ischemic attack (TIA), intracranial bleeding or valvular intervention. Patients were classified in three risk groups (low (<10%), medium (10–30%), high (>30%)) for cardiac syncope based on hs-cTnI and BNP levels. Among 1533 patients, cardiac syncope was the adjudicated final diagnosis in 233 (15.2%). Hs-cTnI and BNP concentrations both remained independent predictors of cardiac syncope in multivariable models. The diagnostic accuracy of the combination hs-cTnI/BNP for cardiac syncope was good with an area under the curve (AUC) of 0.81 (95%-CI 0.78–0.84) and significantly better than each biomarker separately or a set of clinical variables (each p<0.001). The classification of patients in three risk groups, depending on the probability for cardiac syncope based on their hs-cTnI and BNP values, translated well in predictions for MACE (AUC 0.79, 95%-CI 0.77–0.82) and death (AUC 0.78, 95%-CI 0.74–0.82) at 2 years follow-up. Based on these results, we designed a visual tool allowing convenient patient-specific diagnostic and prognostic risk evaluation based solely on hs-cTnI and BNP concentrations (Figure). Risk stratification based on hs-cTnI/BNP The combination hs-cTnI/BNP may have clinical utility in patients presenting to the ED with syncope as it allows good diagnostic as well as prognostic discrimination. Swiss National Science Foundation, Swiss Heart Foundation, Cardiovascular Research Foundation Basel, University Basel