For this study, 125 consecutive patients were recruited. Among them, 14 (11.2%) patients developed CRS within 7 days after admission to the CCU. The demographic characteristics, biomarkers, and clinical presentations are listed in Table 1. Compared with patients without CRS, those with CRS were older (71.9 ± 7.5 vs. 62.9 ± 14.5 years old; p=0.024), had a lower incidence of coronary heart disease (35.7% vs. 71.2%, p = 0.013), were less likely to use ACEI/ARB (57.1% vs. 84.7%, p = 0.022), were more likely to have a history of cerebrovascular disease (28.6% vs. 8.1%, p=0.040), and were more likely to use loop diuretics (78.6% vs. 36.9%, p = 0.004). CRS patients presented lower hemoglobin levels (11.4 ± 2.1 vs. 13.3 ± 2.2 g/dL, p =0.003) and baseline eGFR levels (65.7 ± 34.5 vs. 85.5 ± 35.0 mL/minute/1.73m2, p = 0.048) compared to patients without CRS. CRS patients presented higher BNP plasma levels (1797.2 ± 1649.1 vs. 687.8 ± 976.6 pg/mL, p = 0.008), Ang-2 (7524.7 ± 8485.5 vs. 3325.3 ± 4740.9 pg/mL, p = 0.006), and sTM plasma levels (7763.8 ± 3803.7 vs. 4661.3 ± 1896.8 ng/mL, p < 0.001) compared to patients without CRS. No significant differences were observed between the two groups in terms of gender, comorbidities, smoking status, body mass index (BMI), blood pressure, heart rate, LVEF, leukocyte count, hsCRP, VEGF, vWF, Tie-2, or Ang-1. Multivariate analysis was not performed due to the low incidence of CRS events in the study cohort.
In the study population, 99 patients had baseline eGFR > 60 mL/min/1.73m2, while 26 patients had eGFR < 60 mL/min/1.73m2. The incidence of AKI among patients with eGFR < 60 mL/min/1.73m2 (5/26, 19.2%) was similar to that among patients with eGFR > 60 mL/min/1.73m2 (9/99, 9.1%; odds ratio, 1.13; 95% C.I. 0.92-1.37; p=0.166). Among patients with eGFR < 60 mL/min/1.73m2, we observed higher Ang-2 plasma levels (11573 ± 9441 pg/mL, n=5 vs. 4652 ± 7415 pg/mL, n=21; p = 0.021) and sTM plasma levels (11641 ± 3795 pg/mL, n=5 vs. 7032 ± 2147 ng/mL, n=21; p =0.008) in patients with AKI than in patients without AKI (Figure 1). Among patients with eGFR > 60 mL/min/1.73m2, we also observed elevated Ang-2 plasma levels (5883 ± 7425 pg/mL, n=9 vs. 2951 ± 3825 pg/mL, n= 90; p = 0.05) and sTM plasma levels (6165 ± 2874 pg/mL, n=9 vs. 4102 ± 1323 pg/mL, n=90; p =0.0002) in AKI patients compared with those without AKI. This indicates that baseline eGFR levels were not associated with the difference between sTM and Ang-2 levels in patients with and without CRS.
Table 2 demonstrates the ROC curves of Ang-2 and sTM to predict development of CRS. Areas under the ROC curves (AUROC) revealed that Ang-2 and TM plasma levels had modest discriminative powers pertaining to the development of CRS (0.704, 95% CI 0.55-0.859, p =0.013; and 0.789, 95% CI 0.675-0.903, p <0.001, respectively). The cutoff values for Ang-2 and sTM in predicting AKI were 2479 pg/mL and 4855.2g/mL, respectively.
Figure 2 shows the incidence of AKI stratified by the quartiles of Ang-2 and sTM plasma levels. The incidences of AKI were markedly higher in the 4th quartile group Ang-of2 (8/32, 25%; p=0.032) and 4th quartile group of sTM (8/30, 26.7%; p=0.001) than in the other three quartiles. By contrast, the incidence of AKI was significantly lower in the Ang-2 1st quartile group (1/31, 3.2%) and sTM 1st quartile group (0/32, 0%) than in the other three quartiles.
We also examined the correlation between Ang-2, sTM, Hb concentration, WBC count, hsCRP, and BNP levels. Table 3 lists the correlations between serum mediators and these variables. sTM levels were correlated with the concentrations of Hb (r=-0.516; p<0.001) and BNP (r=0.434; p=0.001). Ang-2 levels were positively correlated with hsCRP (r=0.314; p=0.005) and BNP levels (r=0.696; p<0.001) but negatively correlated with Hb (r=-0.313; p<0.001) and LVEF (r=-0.405; p<0.001) levels.
sTM plasma levels were higher in patients with MACE than in patients without MACE (5892.1± 3495.9 vs. 4754.7 ± 1896.8 pg/mL, p=0.026) (Figure 3A). Ang-2 plasma levels were similar in patients with and without MACE (2902.7 ± 3028.2 vs. 4061 ± 5919 pg/mL, p=0.321). Ang-2 plasma levels were significantly higher in patients with LVEF < 45% (7178 ± 8416 pg/ml) than in patients with LVEF > 45% (2361 ± 2295 pg/ml, p<0.0001) (Figure 3B) as well as significantly higher in patients with Killip class 2 to 4 than in patients with Killip class 1 (4314 ± 5028 vs. 2334 ± 3887 pg/ml, p = 0.0001) (Figure 3C).