Association between P-selectin levels and left atrial blood stasis in patients with nonvalvular atrial fibrillation

Background: P-selectin - a biomarker of platelet and endothelial cell activation is elevated in patients with non-valvular atrial fibrillation (NVAF). However, the association between sP-selectin level and thromboembolic complications in NVAF patients remains controversial. We tested the hypothesis that plasma soluble P-selectin (sPSL) level correlates with the measures of left atrial blood stasis in NVAF. Methods: Plasma sPSL concentration was measured using solid-phase ELISA in 103 NVAF patients (age 63 +/- 14 years; 26% women) and 48 normal sinus rhythm controls (NSR; age 64 +/- 14 years; 41% women) who were not on aspirin. Within the group of NVAF cases, 27 had no spontaneous echocardiographic contrast (SEC) detected by transesophageal echocardiography, 31had mild SEC, 15 moderate, 20 severe, and 10 patients had left atrial appendage thrombus (LAAT). Results: The median soluble sPSL level was higher in NVAF cases compared to NSR controls [(interquartile range) 26 (20-32) ng/mL vs 22 (15-29) ng/mL, p=0.0045]. Only NVAF patients with CHA(2)DS(2)-VASc score >= 1 had higher sPSL level compared to NSR controls. Patients with severe SEC had significantly higher sPSL levels [32 (24-38) ng/mL] compared to all other NVAF patients (p = 0.0042) and to NSR controls (p < 0.0001). Also NVAF patients with LAAT had higher sPSL level compared to NSR controls. Conclusions: There is a direct correlation between p-selectin level and severe blood stasis in the left atrium. Only NVAF patients with CHA2DS2-VASc score >= 1 or with LAAT had higher sPSL level compared to NSR controls.