Inflammation Is Associated With Preoperative Lung Injury In Acute Type A Aortic Dissection

Objective:The patients who have type A aortic dissection often have hypoxemia before operation. We sought to know risk factors which were influence hypoxemia before operation. We detected the expression of C-reactive protein and interleukin6 in patients’ serum and lung tissues. Inflammatory reaction actively participates in this change. Methods: In the first part, 70 person developed type A AAD. Preoperative hypoxemia is defined by an arterial partial oxygen/inspired oxygen fraction(Pa O2/Fi O2) ratio of 200 or lower. We divided the patients into group A(hypoxemia group) and group B(non-hypoxemia group). Data were collected including age、gender、height dissection、weight、current smoking、history of drinking、history of hypertension、history of diabetes mellitus、CRP、D-dimer、PT、creatinine、BNP、ESR、IL-6、LVEF、pericardial effusion、the dissection involving renal artery or mesenteric artery from patients before surgery. After surgery, all patients should do arterial blood gas analysis. Postoperative lung injury is defined by Pa O2/Fi O2 ratio of 200 or lower. In addition, twenty-seven patients were diagnosis type A AAD. They had received at least 4 days of conservative treatment were examined. Every 4 hours, we should exam not only C-reactive protein and Interleukin6 in the serum but also arterial partial. We divided the patients into group A(Lung injury) and group B(nonLung injury). The t test should be used. The analysis of variance also would be used. We need chi-squared(χ2) criterion in our tests. We should do spearman correlation analysis to know the relationships among inflammatory reaction with lung injury. At last, we opted 20 people who owed type A AAD. Ten people had ALI before operation. Ten patients did not have lung injury before operation. CRP and IL6 in patients’ serum were examined. Before establishing extracorporeal circulation, we take some lung tissues(about 0.5g). We used these lung tissues to calculate the rate of wet weight /dry weight. We use a little lung tissues to exam CRP and IL6 by immunohistochemistry. We also use a little lung tissues to quantify CRP and IL6 by RT-PCR. Results Firstly, we find BMI、CRP、D-dimer、IL-6、the dissection involving renal artery or mesenteric artery are the risk facts. In addition, if people had injury in the lung, the peak CRP levels and peak IL6 levers were significantly higher than those without. With the past of time, Oxygenation index was constantly changing with serum CRP level and serum IL6 lever. We also found the distinction between two groups in rate of wet weight /dry weight was significant. The immunohistochemistry demonstrated that the expression of CRP and IL6 in protein levers were significantly high in group A. The RT-PCR demonstrated that the expression of CRP and IL6 in gene levers were little obvious difference. Conclusion Body Mass Index、D-dimer、Systemic inflammatory response、dissection scope are predictors of postoperative hypoxemia in patients with type A AAD. With the past of time, Oxygenation index was continuously changing with serum CRP level and serum IL6 lever. We may safely draw a Conclusion that lung injury in type A AAD was not Lung disease by lung itself. The inflammatory reaction puts up a vital part in this procession.