Prognostic value of cardiac biomarkers in the risk stratification of syncope: a systematic review.

The role of cardiac biomarkers in risk stratification of syncope is unclear. We undertook a systematic review to assess their predictive value for short-term major adverse cardiovascular events (MACE). We conducted a systematic review using MEDLINE, EMBASE, DARE and Cochrane databases from inception to July 2014. We included studies involving adult syncope patients that evaluated cardiac biomarker levels for risk stratification during acute management and excluded case reports, reviews and studies involving children. Primary outcome (MACE) included death, cardiopulmonary resuscitation, myocardial infarction (MI), structural heart disease, pulmonary embolism, significant hemorrhage or cardiac procedural interventions. Secondary outcome analysis assessed for prediction of MI, cardiac syncope and death. Two reviewers extracted patient-level data based on the cut-off reported. Pooled sensitivities and specificities were calculated using patient-level data. A total of 1862 articles were identified, and 11 studies with 4246 patients were included. Studies evaluated 3 biomarkers: contemporary troponin (2693 patients), natriuretic peptides (1353 patients) and high-sensitive troponin (819 patients). The pooled sensitivities and specificities for MACE were: contemporary troponin 0.29 (95 % CI 0.24, 0.34) and 0.88 (95 % CI 0.86, 0.89); natriuretic peptides 0.77 (95 % CI 0.69, 0.85) and 0.73 (95 % CI 0.70, 0.76); high-sensitive troponin 0.74 (95 % CI 0.65, 0.83) and 0.65 (95 % CI 0.62, 0.69), respectively. Natriuretic peptides and high-sensitive troponin showed good diagnostic characteristics for both primary and secondary outcomes. Natriuretic peptides and high-sensitive troponin might be useful in risk stratification.