[High preoperative pulmonary artery systolic pressure is associated with acute kidney injury and prognosis in patients underwent cardiopulmonary bypass surgery].

OBJECTIVE: To observe the relationship between pulmonary artery systolic pressure (PASP) and acute renal injury (AKI) and prognosis after cardiopulmonary bypass (CPB) heart surgery.

METHODS: The clinical data of 9 860 patients who underwent CPB heart surgery in Beijing Anzhen Hospital from January 1st, 2015 to December 31st, 2016 were analyzed retrospectively. The patients were divided into two groups according to whether AKI occurred after operation. The clinical data were obtained from hospital information system (HIS) and DoCare including general information, types of operation, preoperative complication, ejection fraction, serum creatinine (SCr), PASP, intraoperative CPB duration, aortic occlusion duration, fluid balance, blood products and drug usage, postoperative mechanical ventilation duration, length of intensive care unit (ICU) and hospital stay, and perioperative central venous pressure (CVP). Multivariate Logistic regression analysis was used to screen the risk factors of AKI after operation. According to the preoperative PASP level, the patients were divided into ≥ 60 mmHg (1 mmHg = 0.133 kPa) group and < 60 mmHg group, and the incidence of AKI and prognosis after operation were compared between the two groups. All patients were followed up by telephone after discharge, and they were divided into survival group and death group according to the follow-up results, and the clinical data were compared between the two groups. Multivariate Cox regression analysis was used to screen the risk factors of long-term prognosis. Kaplan-Meier survival curve was used to analyze the long-term prognosis of two groups with different preoperative PASP levels.

RESULTS: 6 285 patients were enrolled in the final analysis. (1) Among the 6 285 patients, 2 592 patients (41.2%) suffered from AKI after operation, of whom 1 697 (65.5%) were stage 1 according to Kidney Disease: Improving Global Outcomes (KDIGO), which was the main type of AKI. Univariate analysis showed that age, preoperative ejection fraction, SCr, PASP, coronary heart disease, hypertension, diabetes, intraoperative CPB duration, aortic occlusion duration, fluid balance, red blood cell input and norepinephrine, dopamine, epinephrine dosage, postoperative mechanical ventilation duration, the length of ICU and hospital stay, and perioperative CVP might be the risk factors of AKI after operation. Multivariate Logistic regression analysis showed that preoperative PASP was one of independent risk factors for AKI in patients undergoing CPB heart surgery [odds ratio (OR) = 4.753, 95% confidence interval (95%CI) was 1.328-8.417, P = 0.004]. The incidence of AKI after operation in PASP ≥ 60 mmHg group was significantly higher than that in < 60 mmHg group [73.8% (712/965) vs. 35.3% (1 880/5 320), P < 0.01]. (2) After a follow-up of (11±3) months, 237 patients (3.8%) died in 6 285 patients. The mortality of patients in PASP ≥ 60 mmHg group was significantly higher than that in < 60 mmHg group [9.5% (92/965) vs. 2.7% (145/5 320), P < 0.01]. Kaplan-Meier survival curve analysis showed that there was a significant difference between the two groups in cumulative survival rate (Log-Rank test: χ2 = 144.400, P < 0.001). Univariate analysis showed that male, age, preoperative hypertension, ejection fraction, PASP, intraoperative CPB duration, aortic occlusion duration, fluid balance, epinephrine dosage, postoperative mechanical ventilation duration, the length of ICU and hospital stay, and perioperative CVP might be risk factors for long-term death of patients undergoing CPB heart surgery. Multivariate Cox regression analysis showed that for every 1 mmHg increase in preoperative PASP, the long-term mortality increased by 1.126 times [hazard ratio (HR) = 1.126, 95%CI was 1.003-1.604, P = 0.021].

CONCLUSIONS: The increase of PASP is related to AKI after CPB heart surgery, which is an independent risk factor for long-term mortality.