Ambispective Cohort Study on the Correlation Between 4G/5G Polymorphism of Plasminogen Activator Inhibitor-1 (PAI-1) Promoter and Moderate to Severe Postoperative Acute Renal Injury in Patients With Aortic Dissection

The incidence of postoperative acute kidney injury（AKI）after cardiac surgery is high, especially in patients with aortic dissection. Moderate to severe postoperative AKI (stage 2 and 3 AKI) is closely related to the poor prognosis after cardiac surgery. Patients with Stanford type A dissection who suffered from stage 2 and 3 postoperative AKI will have a 4.45 times higher mortality than that of patients without AKI. At present, there is no effective treatment for cardiac surgery associated AKI (CSA-AKI), and prevention is more important than treatment. Therefore, screening high-risk patients and implementing individualized preventive measures are of great significance for the prevention of postoperative AKI and improvement of prognosis of patients.

The previous completed RCT study in the investigators' center showed that perioperative administration of inhaled nitric oxide (NO) to patients undergoing cardiopulmonary bypass (CPB) assisted multivalve replacement surgery could significantly reduce the incidence of postoperative AKI, but the NO should be provided before CPB was started, that is, when injury began. This phenomenon implied that NO played a preventive role rather than a therapeutic role. In further studies, the investigators found that the kidney protective mechanism of NO inhalation may be related to its role on PAI-1 regulation. According to the literature, the 4G5G polymorphism in the promoter region of PAI-1 is a natural regulator of the expression level of PAI-1 in vivo. Based on these findings, the investigators reviewed some cases who underwent aortic dissection correction surgery and also PAI-1 4G5G polymorphism test in our hospital, the investigators found that 4G/4G homozygous patients had a much higher proportion of moderate to severe AKI than 4G5G heterozygous patients or 5G/5G homozygous patients. However, due to the small sample size, the differences in AKI incidence between different genotype groups were not statistical significant.

In order to further explore the association between PAI-1 4G5G polymorphism and the risk of CSA-AKI, the investigators planed to expand the sample size and form a ambispective cohort study which include the retrospective cohort mentioned above and a new prospective cohort study. A total of 255 patients will be included to determine the genetic susceptibility of CSA-AKI associated with PAI-1 4G5G deletion / insertion polymorphism. All subjects included in the prospective part of this study will receive PAI-1 4G5G polymorphism test, and record whether postoperative AKI occurs and also AKI stage. There is no other intervention for patients included in this study in addition to blood collection. All medical decision-making processes in hospital will not be interfered by the research.