Atrial Natriuretic Peptide (ANP) Independently Predicts Latent Paroxysmal Atrial Fibrillation in Embolic Stroke Patients
Background
Embolic stroke of undetermined source (ESUS) accounts for a significant portion of ischemic strokes, with paroxysmal atrial fibrillation (PAF) being a major underlying cause. Detecting PAF is challenging as it often goes undiagnosed during initial presentation, leaving patients at risk for recurrent stroke. Current diagnostic methods, like standard ECG monitoring, frequently miss intermittent PAF episodes. Identifying reliable, acute biomarkers that reflect atrial stress and predict latent PAF could significantly improve secondary stroke prevention strategies. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are cardiac hormones released in response to atrial and ventricular stretch, respectively, making them potential candidates for reflecting cardiac load and identifying underlying arrhythmias.
Study Design
This prospective, single-center cohort study enrolled 64 patients presenting with embolic stroke of undetermined source (ESUS) within 24 hours of symptom onset, excluding those with admission atrial fibrillation (AF). Researchers measured admission plasma levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). All patients underwent 14-day continuous ECG monitoring to screen for latent paroxysmal atrial fibrillation (PAF). Patients were then categorized into either a PAF-detected group or an ESUS group. Logistic regression analysis, incorporating left atrial diameter (LAD), ANP, and BNP, was used to assess independent associations with PAF detection, while receiver operating characteristic (ROC) analysis evaluated diagnostic performance.
Results
Out of 111 initial ESUS patients, 64 were included in the final analysis, with 30 patients (46.9%) subsequently diagnosed with paroxysmal atrial fibrillation (PAF) via 14-day continuous ECG. Baseline comparisons revealed significant differences in age, ANP, BNP, and left atrial diameter (LAD) between the PAF-detected and ESUS groups. > In multivariable logistic regression, ANP was independently associated with PAF detection (p=0.015), while BNP and LAD were not significant predictors. ROC analysis demonstrated an area under the curve (AUC) of 0.901 (95% CI, 0.818-0.984) for ANP and 0.892 (95% CI, 0.811-0.973) for BNP, with no significant difference between their diagnostic performances (p=0.821). A clinically useful cutoff value for ANP was identified at 63.9 pg/mL, yielding a sensitivity of 94.1% and a specificity of 83.3% for detecting PAF.
Key Findings
- Atrial Natriuretic Peptide (ANP) was an independent predictor of paroxysmal atrial fibrillation (PAF) detection in ESUS patients (p=0.015).
- ANP showed strong diagnostic performance for PAF, with an AUC of 0.901.
- A cutoff value of 63.9 pg/mL for ANP yielded 94.1% sensitivity and 83.3% specificity for PAF detection.
- Brain Natriuretic Peptide (BNP) also showed high diagnostic performance (AUC 0.892) but was not an independent predictor in multivariable analysis.
Why It Matters
ANP emerges as a promising, readily available biomarker for identifying latent paroxysmal atrial fibrillation (PAF) in patients with embolic stroke of undetermined source (ESUS), potentially enabling earlier intervention. Given its atrial origin and very short half-life, ANP levels may offer a more acute and specific reflection of atrial load compared to BNP, which is also influenced by ventricular function. This finding suggests that measuring ANP in acute stroke settings could guide targeted, prolonged ECG monitoring or early initiation of anticoagulation, improving secondary stroke prevention. While a specific protocol isn't provided, the identified cutoff value of 63.9 pg/mL offers a practical threshold for clinical consideration. This could lead to a more efficient and cost-effective screening strategy, reducing the burden of undiagnosed PAF and subsequent stroke recurrence.