Increased Preoperative Serum Apoptosis Marker Fas Ligand Correlates with Histopathology and New-Onset of Atrial Fibrillation in Patients After Cardiac Surgery

Increased Preoperative Serum Apoptosis BackgroundWe evaluated if preoperative serum apoptosis markers correlate with atrial histological remodeling and postoperative atrial fibrillation (POAF) after cardiac surgery. Methods and ResultsA total of 33 patients with sinus rhythm (SR) and without history of atrial fibrillation (AF) undergoing cardiac surgery were prospectively enrolled. Serum concentrations of Fas (apoptosis-stimulating fragment ligand) and TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) were measured preoperatively. Right atrial appendage (RAA) tissue was obtained during surgery. Atrial apoptosis was assessed via TUNEL assay and degree of atrial fibrosis was categorized histologically by visual quantification. Continuous ECG-Monitoring was used to screen for POAF throughout 10 days after cardiac surgery. POAF occurred in 15 patients (45%). Atrial apoptosis was higher in patients with POAF as compared to those without (35.9 9.8% vs 14.5 +/- 7.5%; P < 0.0001) and correlated with the degree of atrial fibrosis (r = 0.69; P < 0.0001). In contrast to TRAIL (87.0 +/- 8.2 pg/mL vs 83.3 +/- 9.4 pg/mL; P = 0.77), preoperative Fas serum concentration was significantly higher in patients with POAF compared to patients in stable SR (91.3 +/- 7.2 pg/mL vs 66.7 +/- 3.0 pg/mL; P < 0.01). Serum Fas concentration correlated with the degree of atrial apoptosis (r = 0.63; P < 0.001) and the degree of atrial fibrosis (r = 0.39; P < 0.05). ConclusionPreoperative evaluation of serum apoptosis marker Fas is useful to identify patients at risk for POAF undergoing cardiac surgery. Fas but not TRAIL correlates with the documented degree of atrial apoptosis and atrial fibrosis in RAA tissue. Further studies need to identify the prospective role of Fas in predicting POAF events.