Blood biomarkers to detect new-onset atrial fibrillation and cardioembolism in ischemic stroke patients

BACKGROUND Accumulating data suggest blood biomarkers could inform stroke etiology. OBJECTIVE The purpose of this study was to investigate the performance of multiple blood biomarkers in elucidating stroke etiology with a focus on new-onset atrial fibrillation (AF) and cardioembolism. METHODS Between January and December 2017, information on clinical and laboratory parameters and stroke characteristics was prospectively collected from ischemic stroke patients recruited from the National University Hospital, Singapore. Multiple blood biomarkers (N-terminal pro-brain natriuretic peptide [NT-proBNP], D-dimer, S100 beta, neuron-specific enolase, vitamin D, cortisol, interleukin-6, insulin, uric acid, and albumin) were measured in plasma. These variables were compared with stroke etiology and the risk of new-onset AF and cardioembolism using multivariable regression methods. RESULTS Of the 515 ischemic stroke patients (mean age 61 years; 71% men), 44 (8.5%) were diagnosed with new-onset AF, and 75 (14.5%) had cardioembolism. The combination of 2 laboratory parameters (total cholesterol <= 169 mg/dL; triglycerides <= 44.5 mg/dL) and 3 biomarkers (NT-proBNP >= 294 pg/mL; S100 beta >= 64 pg/mL; cortisol >= 471 nmol/l) identified patients with new-onset AF (negative predictive value [NPV] 90%; positive predictive value [PPV] 73%; area under curve [AUC] 85%). The combination of 2 laboratory parameters (total cholesterol <= 169 mg/dL; triglycerides <= 44.5 mg/dL) and 2 biomarkers (NT-proBNP >= 507 pg/mL; S100 beta >= 65 pg/mL) identified those with cardioembolism (NPV 86%; PPV 78%; AUC 87%). Adding clinical predictors did not improve the performance of these models. CONCLUSION Blood biomarkers could identify patients with increased likelihood of cardioembolism and direct the search for occult AF.