ACS patients with lower plasma calprotectin level versus ACS patients with higher plasma calprotectin level
A total of 176 ACS patients was included in this study. The 176 patients were divided into 2 groups according to the median of calprotectin detected in our study (3681ng/ml). There were 83 patients (mean age 63 ± 10 and 65.1% male) in lower calprotectin group (group 1) and 93 patients (mean age 65 ± 12 and 76.1% male) in higher calprotectin group (group 2). Baseline clinical characteristics and laboratory factors are shown in Table 1. Mean age was not significantly different. There were more ST segment elevation ACS (STE-ACS) patients (58 (63.0%) vs. 15 (18.1%), p＜0.001) and higher grace scores (139.03±36.73 vs. 102.23±36.27, p＜0.001) in group 2 compared with group 1. With respect to coronary risk factors, there was significant higher presence of diabetes mellitus (p = 0.012) in group 2 than in group 1. However, no significant difference were found in hypertension, smoking, hypercholesterolemia, body mass index and previous coronary artery disease (CAD) history between groups (all p＞0.05).
With respect to baseline laboratory variables, the serum total cholesterol (TC) and low density lipoprotein cholesterol (LDL-c) were significantly higher in group 2 than in group 1 (p = 0.037 and p=0.007 respectively). Serum glucose on admission and fasting blood glucose were also significantly higher in group 2 (p = 0.009 and p = 0.018 respectively), while there were no significant differences in high density lipoprotein cholesterol (HDL-c), triglyceride, blood hemoglobin, platelet, mean platelet volume (MPV)，platelet distribution width (PDW) between groups (all p＞0.05). Compared with group 1, high-sensitive cardiac troponin I (hs-cTnI) on admission and B-type natriuretic peptide (BNP) on admission were found to be significantly higher in group 2 (p＜0.001). In addition, the other admission parameters comprising serum Creatine, blood urea nitrogen, C-reactive protein (CRP), D-Dimer, white blood cell count (WBC) and neutrophil count were higher in group 2 than in group 1 (p =0.001, p = 0.026, p = 0.005, p = 0.002, p = 0.003 and p =0.001 respectively). As for echocardiography variables, significantly higher left ventricular diastolic diameter (LVDd) and lower left ventricle ejection fraction (LVEF) were found in group 2 (p =0.005 and p =0.004). However, previous medication history of variable drugs were not significantly different between groups (all p＞0.05). (Table 1)
Patients in group 2 seemed to have higher in-hospital mortality (4(4.3%) vs. 1(1.2%), p=0.217) and in-hospital MACE (8(8.6%) vs. 3(3.6%), p=0.172) compared with in group 1, but the difference was not significant. The no-reflow was much more frequent in group 2 than in group 1 (21(22.8%) vs. 1(1.2%), p＜0.001). (Table 1)
ACS patients with no-reflow versus ACS patients without no-reflow
Compared with group 1, platelet activation biomarker PMA was found to be significantly higher in group 2 (p＜0.001) (Table 1). ACS patients with no-reflow had higher plasma calprotectin and PMA compared with those without no-reflow (6062.9±999.8 vs 3625.7±1526.8 ng/ml, p<0.001; 47.58±12.30 % vs 36.73±12.55%, p<0.001, respectively) as shown in figure 1 (A and B).
Determinants of plasma calprotectin and PMA in ACS patients
The analyses of correlation demonstrated that either calprotectin or PMA were positively associated with hs-cTnI on admission, BNP on admission, glucose on admission, GRACE score, LDL-c, TC, CRP, WBC and neutrophil lymphocyte ratio (N/L). Calprotectin and PMA were negatively associated with LVEF (Table 2). Figure 2 showed that calprotectin was positively correlated with PMA (r=0.439, p<0.001). Only calprotectin and hs-cTnI on admission were found to be independently associated with PMA as shown in table 3.
Determinants of no-reflow in ACS patients
The analysis of univariate logistic regression revealed that no-reflow was associated with calprotectin, PMA, diabetes mellitus history, LDL-c, N/L ratio, glucose on admission and BNP on admission (all p<0.05). The multivariate logistic regression showed that only calprotectin and LDL-c were independent predictors of no-reflow (p< 0.001 and p=0.017 respectively) (Table 4). The ROC curves of calprotectin and LDL-c for predicting no-reflow were shown in figure 3. AUROC of calprotectin and LDL-c for predicting no-reflow were 0.898 and 0.779, respectively. The cut-off value of plasma calprotectin for no-reflow was 4748.77 ng/ml with a sensitivity of 0.95 and a specificity of 0.77. The cut-off value of LDL-c for no-reflow was 3.06 mmol/l with a sensitivity of 0.77 and a specificity of 0.69.