Predictive Value of Baseline C - reactive protein for Slow Flow/No-Reflow Following Primary Percutaneous Coronary Intervention in Patients with Acute ST-Elevation Myocardial Infarction

Abstract

Objective: This study evaluated the diagnostic and predictive value of baseline C-reactive protein (CRP) for slow flow/no-reflow following primary percutaneous coronary intervention (PCI) in patients presenting with acute ST-elevation myocardial infarction (STEMI). Methodology: This analytical cross-sectional study included 550 consecutive adult patients with acute STEMI who underwent primary PCI at the National Institute of Cardiovascular Diseases, Karachi, Pakistan. Baseline CRP was measured on hospital admission before coronary intervention. The primary outcome was angiographic slow flow/no-reflow, defined as final Thrombolysis in Myocardial Infarction (TIMI) flow grade 0–II after PCI. Results: The median age of the study population was 58.0 years (IQR: 50.0–67.0), and 388 (70.5%) participants were male. Normal coronary reperfusion (TIMI III) was achieved in 440 patients (80.0%), while 110 patients (20.0%) developed slow flow/no-reflow. Baseline CRP concentrations were significantly higher among patients with slow flow/no-reflow than those with normal coronary flow (1.52 [0.90–2.74] mg/L vs. 0.84 [0.50–1.26] mg/L; p<0.001). ROC analysis demonstrated fair predictive performance (AUC=0.730; 95% CI: 0.675–0.782). The optimal CRP cut-off value of 1.44 mg/L yielded a sensitivity of 53.6%, specificity of 81.6%, and overall diagnostic accuracy of 76.0%. After adjustment for demographic, clinical, angiographic, and procedural variables, baseline CRP remained an independent predictor of slow flow/no-reflow (adjusted OR=1.82; 95% CI: 1.33–2.48; p<0.001). Conclusion: Baseline CRP is independently associated with slow flow/no-reflow following primary PCI in patients with acute STEMI and demonstrates fair discriminatory ability. However, because of its moderate sensitivity and limited positive predictive value, CRP should be considered an adjunctive biomarker and interpreted together with clinical, angiographic, and procedural risk factors rather than as a standalone predictor.