[The levels of angiopoietin-2 in patients with acute respiratory distress syndrome and its value on prognosis].

OBJECTIVE: To approach the correlation between angiopoietin-2 (Ang-2) levels and degree of lung injury and prognosis and its clinical significance in patients with acute respiratory distress syndrome (ARDS).

METHODS: A prospective observation was conducted. Fifty-three ARDS patients admitted to Department of Critical Care Medicine of Third Affiliated Hospital of Anhui Medical University from January 2012 to March 2014 were enrolled. According to the criteria of the Berlin Definition of ARDS, the patients were divided into mild group (n=15), moderate group (n=22) and severe group (n=16). Meanwhile, ARDS patients were further divided into survival group(n=29) and non-survival group(n=24) according to 28-day outcomes. Twenty cases of non-ARDS patients were served as control. The acute physiology and chronic health evaluation II(APACHEII) score, sequential organ failure assessment (SOFA) score, oxygenation index (PaO₂/FiO₂), lung injury score (LIS) were recorded within 24 hours after admission. And the plasma levels of Ang-2, interleukin-6 (IL-6) and C-reaction protein (CRP) were measured. The independent risk factors of ARDS were analyzed by univariate and multivariable logistic regression. Receiver operating characteristic curve (ROC) was plotted to evaluate the value of Ang-2 in predicting ARDS.

RESULTS: Compared with non-ARDS group, APACHEII score, SOFA score, LIS score, mortality were significantly increased, PaO2/FiO2 was significantly decreased, and plasma Ang-2, IL-6, CRP were significantly elevated [APACHEII score: 20.7 ± 5.0 vs. 14.1 ± 5.3, SOFA score: 7.7 ± 3.5 vs. 3.5 ± 2.1, LIS score: 1.69 ± 0.71 vs. 0.28 ± 0.27, PaO₂/FiO₂(mmHg, 1 mmHg = 0.133 kPa): 159.5 ± 61.3 vs. 394.0 ± 3.2, mortality: 45.3% (24/53) vs. 20.0% (4/20), Ang-2(μg/L): 4.73(2.59, 6.99)vs. 1.22 (0.61, 1.52), IL-6(ng/L): 56.50 (27.15, 139.90)vs. 13.05 (4.38, 15.55), CRP (mg/L): 95.75(41.74, 189.72) vs. 10.56 (3.92, 21.36), P<0.05 or P<0.01]. Each index increased or decreased more significantly with the aggravation of the disease. It was shown by correlation analysis that the plasma levels of Ang-2 was significantly positive correlated with IL-6 (r=0.468,P=0.000), CRP(r = 0.492, P = 0.000), APACHEII score (r = 0.560, P = 0.000), SOFA score (r = 0.508, P = 0.000) and LIS score (r = 0.588, P = 0.000), significantly negatively correlated with PaO2/FiO2 (r=-0.685,P=0.000). Factors, APACHEII score, LIS score, PaO2/FiO2, Ang-2 and IL-6 founded statistical significance in univariate analysis were analyzed using multivariable logistic regression. High APACHEII score at admission [odds ratio (OR) = 1.316, 95% confidence interval (95% CI) = 1.040-1.633, P = 0.022] and increased plasma Ang-2 levels (OR = 1.287, 95% CI = 1.041-1.760, P = 0.038) were the independent prognostic factors for the 28-day mortality in ARDS. The area under the ROC curve of Ang-2 was 0.964, the optimal critical value of Ang-2 was 1.79 μg/L, the specificity was 90.0%, and sensitivity was 92.5%. Plasma levels of Ang-2 was better in predicting ARDS than APACHEII score, SOFA score and IL-6.

CONCLUSIONS: The plasma level of Ang-2 was significantly increased in patients with ARDS. The plasma level of Ang-2 was correlated with the severity of acute lung injury and had important prognosis evaluation.