Ognjen, Gajic

Variability in novel inflammatory markers (HBP and SAA) post-surgery could indicate ongoing perioperative inflammation. This pilot cohort study collected blood from 99 patients undergoing elective cardiac surgery at baseline, 24 hours, 7 days, and 3 months post-surgery. Inflammatory markers (HBP, SAA, PCT, CRP, IL-6) were measured with a point-of-care device. Demographic and clinical data were extracted from health records. Serum SAA increased significantly in the acute postoperative phase (M e [IQR];SAA baseline =81.1[87] vs SAA 24hr= 232.65[88.02];U[72]=2343,p<0.0001), remained elevated at 7 days (Me 7d =252.6[88.56];U[57]=1484,p<0.0001) and were still more pronounced than baseline at t 3m (Me 3m =118.44[101.52];U[38]=448,p=0.0008). HBP showed a significant rise at seven days (HBP baseline =45[26;89] vs HBP 7d =121[69.75;224.5]; U[56]=805,p<0.0001) then returned to near baseline by t 3m (Me 3m =32.5[15.75;98.5]). Traditional inflammatory markers PCT, CRP, and IL-6 demonstrated a rapid increase at t 24h and plateaued at t 7d . None of the biomarkers showed variability at baseline or postoperatively with preoperative status or postoperative complications. Cluster analysis of the inflammatory markers at 24 hours (t 24h ) identified distinct subgroups. Cluster #1-patients with a modest increase in all markers; Cluster#2 characterized with a robust increase in IL-6; Cluster #3 showed increase in CRP and decline in HBP; Cluster #4 showed a modest increase in IL-6 and decline in HBP; Cluster #5 represented a decline in both CRP and SAA. Patients in these clusters differ with respect to age, pre-existing peripheral artery disease, and borderline differences in perioperative acetaminophen use. SAA and HBP remain elevated longer than IL-6, CRP, and PCT after surgery, suggesting that inflammation may persist beyond 3 months.