Independent risk factors and the long-term outcomes for postoperative continuous renal replacement treatment in patients who underwent emergency surgery for type a acute aortic dissection

OBJECTIVE: The study objective was to investigate the incidence and risk factors of continuous renal replacement therapy (CRRT) in patients undergoing emergency surgery for type A acute aortic dissection (TA-AAD) and evaluate the perioperative and long-term outcomes. METHODS: From January 2014 to December 2018, 712 consecutive patients were enrolled in the study. These patients were divided into two groups according to whether or not needed postoperative CRRT: the CRRT group vs the control group. Univariate analysis and binary logistic regression analysis were used to analyze the risk factors of CRRT. To avoid the selection bias and confounders, baseline characteristics were matched for propensity scores. Kaplan-Meier curves were generated to provide survival estimates at postoperative points in time. RESULTS: Before propensity score matching, univariate analysis showed that there were significant differences in age, preoperative hypertension, pericardial effusion, preoperative serum creatinine (sCr), intraoperative need for combined coronary artery bypass grafting (CABG) or mitral valve or tricuspid valve surgery, cardiopulmonary bypass (CPB) time, extracorporeal circulation assistant time, aortic cross-clamp time, drainage volume 24 h after surgery and ventilator time between two groups. All were higher in the CRRT group (P < 0.05). These risk factors were included in binary logistic regression. It showed that preoperative sCr and CPB time were independent risk factors for CRRT patients undergoing surgery for TA-AAD. And there were significant differences regarding 30-day mortality (P < 0.001) and long-term overall cumulative survival (P < 0.001) with up to a 6-year follow-up. After propensity scoring, 29 pairs (58 patients) were successfully matched. Among these patients, the analysis showed that CPB time was still significantly longer in the CRRT group (P = 0.004), and the 30-day mortality rate was also higher in this group (44.8% vs 10.3%; P = 0.003). CONCLUSION: CRRT after TA-AAD is common and worsened short- and long- term mortality. The preoperative sCr and CPB time are independent risk factors for postoperative CRRT patients. Shorten the CPB time as much as possible is recommended to reduce the risk of CRRT after the operation.