Increased plasma levels of N-terminal pro-B-type natriuretic peptide as biomarker for the diagnosis of cardioembolic ischaemic stroke

Background: Despite comprehensive study, the aetiology of stroke is not identified in 35% of cases.

Aims: We conducted a study to assess the diagnostic capacity of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in the identification of ischaemic stroke of cardioembolic origin. The secondary purpose of the study was to evaluate the prognostic value of NT-proBNP for predicting 90-day all-cause mortality.

Methods: We designed a prospective observational study including patients hospitalised due to stroke between March 2019 and March 2020. Blood samples were collected on admission to the emergency department and serum NT-proBNP levels were determined. Statistical analysis was performed using a bivariate logistic regression model and receiver operating characteristic (ROC) and Kaplan-Meier curves. Statistical significance was established at p<.05.

Results: The study included 207 patients with first ischaemic stroke. Plasma NT-proBNP levels were significantly higher (p<.001) in the cardioembolic stroke group (2069pg/mL±488.5). ROC curves showed that NT-proBNP>499pg/mL was the optimum value for diagnosing cardioembolic ischaemic stroke (sensitivity, 82%; specificity, 80%). Moreover, plasma NT-proBNP levels>499pg/mL were independently associated with cardioembolic stroke (OR: 9.881; p=.001). Finally, NT-proBNP>1500pg/mL was useful for predicting 90-day mortality (sensitivity, 70%; specificity, 93%).

Conclusions: NT-proBNP was independently associated with cardioembolic stroke and should be quantified in blood tests within 24h of stroke onset. High plasma levels (>499pg/mL) may indicate an underlying cardioembolic cause, which should be further studied, while NT-proBNP >1500pg/mL was associated with increased 90-day mortality.