Serum C - Reactive Protein Level as a Predictor of New-Onset Postoperative Atrial Fibrillation in Off-Pump Coronary Artery Bypass Grafting

Abstract

Background: Postoperative atrial fibrillation (POAF) complicates up to 30% of coronary artery bypass grafting procedures and is linked to prolonged hospitalization, increased stroke risk, and higher mortality. Although off‑pump CABG (OPCAB) avoids cardiopulmonary bypass–induced inflammation, POAF remains common, suggesting that even minimal surgical trauma provokes an inflammatory environment sufficient to trigger arrhythmia. Serum C‑reactive protein (CRP) is an inexpensive, readily available marker of systemic inflammation; if elevated early after surgery, it may identify patients at higher arrhythmic risk and thus guide targeted prophylaxis. Methods: In this analytical cross‑sectional study, 100 consecutive OPCAB patients (age 35–70 years) were enrolled at the Armed Forces Institute of Cardiology/NIHD, Rawalpindi. Daily serum CRP was measured from postoperative day (POD) 0 through POD5. Patients were stratified into two groups CRP < 10 mg/L versus CRP ≥ 10 mg/L based on the operational definition of elevated inflammation. Continuous ECG monitoring and daily 12‑lead ECGs identified new‑onset POAF (absence of P waves, irregular RR intervals) within five days. Multivariate logistic regression adjusted for hypertension, diabetes, albumin level, and other confounders. Results: POAF incidence was significantly higher in the elevated‑CRP group (36% vs. 14%, p=0.02). After adjustment, CRP ≥ 10 mg/L conferred a 1.29‑fold increased odds of POAF (95% CI: 1.09–1.52; p=0.03), hypertension a 4.7‑fold increase (p=0.02), and hypoalbuminemia a protective but clinically counterintuitive association (aOR 0.05; p=0.01), likely reflecting complex nutritional–inflammatory interactions. Receiver‑operator characteristic analysis yielded an AUC of 0.68 for CRP (cut‑off 10 mg/L), with 72% sensitivity and 57% specificity, underscoring moderate discrimination. Conclusion and Implications: Elevated early postoperative CRP independently predicts POAF in OPCAB patients, affirming the causal role of surgical inflammation in arrhythmogenesis. Although CRP alone offers moderate accuracy, its routine measurement could flag high‑risk individuals for intensified monitoring, anti‑inflammatory prophylaxis (e.g., colchicine, statins), or early antiarrhythmic therapy. Integrating CRP into multifactorial risk models may enhance personalized perioperative care and ultimately reduce the burden of POAF.