Serial Assessment of Natriuretic Peptides in Patients Undergoing Interventional Closure of the Left Atrial Appendage

Abstract

Background: Closure of the left atrial appendage (LAA) to prevent cardioembolic events is an alternative therapy to oral anticoagulation in patients with non-valvular atrial fibrillation. The LAA is an important source of natriuretic peptides and its exclusion from the circulation may alter the blood level of these hormones, thereby influencing their diagnostic value and clinical effects.

Methods: We aimed to prospectively assess potential changes in mid-regional pro A-type natriuretic peptide (MR-proANP) and N-terminal pro B-type natriuretic peptide (NT-proBNP) levels 6 weeks and 6 months after interventional LAA closure using the WATCHMAN device.

Results: In 29 consecutive patients with successful LAA closure baseline MR-proANP level was 274±208pmol/l and decreased by -24.5±68 (p=0.07) and -15.0±44pmol/l (p=0.10) after 6 weeks and 6 months, respectively. The drop in the MR-proANP level after 6 weeks and 6 months was significant in patients with elevated (≥214pmol/l) baseline MR-proANP level (n=15: -54.3±78.0, p<0.01 and -31.8±45.4pmol/l, p=0.03, respectively) and those with reduced left ventricular ejection fraction (LVEF<45%, n=7: -87.4±97.3, p=0.02 and -60.3±42.6pmol/l, p=0.01, respectively). Baseline NT-proBNP level (median 1054pg/ml; IQR 621-1977pg/ml), sodium, potassium, mean systolic or diastolic blood pressure did not change significantly in the mentioned patient groups.

Conclusions: After LAA closure, MR-proANP level decreased significantly in patients with elevated baseline MR-proANP level or reduced LVEF, whereas NT-proBNP level remained unchanged, thereby altering the correlation coefficient between the two biomarkers. Our findings should be considered when using these biomarkers for diagnostic or prognostic evaluation in patients with interventional LAA closure.

Keywords: LAA closure; MR proANP; NT proBNP; Natriuretic peptides; WATCHMAN device.