Diagnostic and prognostic value of troponins and natriuretic peptides in syncope: a systematic review and meta-analysis

The diagnostic and prognostic values of brain natriuretic peptide (BNP), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and high-sensitivity cardiac troponins T (hs-cTnT) and I (hs-cTnI) in syncope remain to be elucidated. The objective of this study is to conduct a thorough assessment of their utility in diagnosing and predicting outcomes for syncope patients.

A comprehensive literature search was performed in PubMed, Embase, Cochrane Library, and Web of Science databases up to June 20, 2023. Studies were included if they were original English-language cohort research articles involving human participants with sufficient data to determine diagnostic metrics. The quality of the studies on diagnostic accuracy was evaluated using the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies-2) tool. The random-effect model was used to address heterogeneity. The diagnostic and prognostic metrics, including sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratio, and the area under the summary receiver operating characteristic curve (AUC), all accompanied by their respective 95% confidence intervals (CIs) were reported. Subgroup analyses were conducted based on the follow-up time.

In total, 16 articles involving 12,547 patients were included. The majority of the studies exhibited low risk in both bias and clinical applicability, with a few exceptions. BNP demonstrated a combined sensitivity and AUC of 0.80 (95% CI: 0.75-0.84) and 0.86 (95% CI: 0.82-0.91), respectively, in identifying cardiac syncope. However, hs-cTnT and hs-cTnI demonstrated a modest decrease in sensitivity (0.75, 95% CI: 0.71-0.78; 0.80, 95% CI: 0.75-0.85, respectively) in identifying cardiac syncope. NT-proBNP showed a slightly higher combined sensitivity and AUC, with values of 0.85 (95% CI: 0.82-0.88) and 0.81 (95% CI: 0.63-0.99), respectively, in identifying cardiac syncope. Regarding the predictive performance of these biomarkers for unfavorable outcomes, BNP had a combined AUC of 0.82 (95% CI: 0.73-0.91). NT-proBNP exhibited a similar predictive capability with a combined AUC of 0.80 (95% CI: 0.74-0.85). In contrast, hs-cTnT showed a lower predictive performance with a combined AUC of 0.71 (95% CI: 0.61-0.80) For follow-up periods of ≤1 month, the pooled sensitivity of BNP for predicting adverse outcomes was 0.41 (95% CI: 0.32-0.50), while for periods exceeding 1 month, it increased to 0.87 (95% CI: 0.69-0.96). For follow-up periods of ≤1 month, the pooled sensitivity of NT-proBNP for predicting adverse outcomes was 0.88 (95% CI: 0.85-0.91), while for periods exceeding 1 month, it decreased to 0.69 (95% CI: 0.58-0.78).

BNP, NT-proBNP, and high-sensitivity troponin showed good diagnostic and prognostic abilities for syncope, indicating that they may be applied to improve risk stratification and outcomes of syncope patients.