Risk Factors Of Cardiac Valve Calcification And Its Effect On The Prognosis Of Peritoneal Dialysis Patients

Objective:To explore the risk factors of cardiac valve calcification in pre-dialysis uremia patients and peritoneal dialysis patients and its effect on the prognosis of peritoneal dialysis patients,so as to guide clinical treatment and improve prognosis.Method:The subjects were peritoneal dialysis patients who underwent peritoneal dialysis catheterization in the Department of Nephrology,Second Hospital of Jilin University from January 2012 to June 2018.All patients underwent cardiac ultrasonography at the time of catheterization and at least three months after catheterization.According to whether there was cardiac valve calcification at the time of catheterization,they were divided into calcification group and non-calcification group at baseline.The noncalcification group was further divided into newly developed calcification group and non-newly developed calcification group according to whether new cardiac valve calcification occurred during the follow-up period.General clinical data and laboratory findings of all patients were collected during catheterization.At the end of the followup,patients were divided into two groups according to whether they had calcification of cardiac valves,the valvular calcification group(including calcification group at baseline and newly developed calcification group)and the non-valvular calcification group.And then the cardiac function parameters of patients in the calcification group and non-calcification group at baseline and in the valvular calcification group and nonvalvular calcification group at the end of follow-up were compared.Multivariate logistic regression was used to analyze the risk factors of cardiac valve calcification in pre-dialysis uremia patients and peritoneal dialysis patients.Kaplan-Meier method was used to calculate the cumulative survival rate and Cox regression was used to analyze the risk factors affecting the survival rate.All patients were followed up until 31 December 2018 and their outcomes were analyzed.The end points of follow-up were death,combined dialysis,conversion to hemodialysis or kidney transplantation.Results:1.A total of 189 patients were enrolled in the study,and 30 patients had cardiac valve calcification at the time of catheterization for peritoneal dialysis,accounting for 15.9% of the total.After a median follow-up of 26(14.5,37.5)months,60 patients with cardiac valve calcification have been found so far,including 52 patients of simple aortic valve calcification,2 patients of simple mitral valve calcification and 6 patients of aortic valve plus mitral valve calcification.Thirty-two patients had newly developed cardiac valve calcification during the study,including 2 patients of newly developed cardiac valve calcification on the basis of previous calcification at baseline,and 30 patients of newly developed cardiac valve calcification during dialysis without any calcification at baseline.2.Compared with the non-calcification group,the patients in the calcification group at baseline were older,higher in urea nitrogen and lower in albumin.The difference was statistically significant(P<0.05).Multivariate Logistic regression analysis showed that the age and blood urea nitrogen were independently positively correlated with cardiac valve calcification at baseline while albumin was independently negatively correlated with cardiac valve calcification at baseline.Compared with the non-newly developed calcification group,the patients in the newly developed calcification group were older,and had a high proportion of hypertension,high level of alkaline phosphatase and low hemoglobin and albumin.The difference was statistically significant(P<0.05).Multivariate Logistic regression analysis showed that alkaline phosphatase and hypertension were positively correlated with newly developed cardiac valve calcification,while albumin was negatively correlated with newly developed cardiac valve calcification.3.The difference in left ventricular ejection fraction and E/A was statistically significant(P<0.05)between the calcification group and non-calcification group at baseline.However,the difference in left atrial diameter,left ventricular diastolic diameter,interventricular septal thickness,left ventricular posterior wall thickness,left ventricular fractional shortening,left ventricular hypertrophy,moderate to severe mitral valve insufficiency and moderate to severe aortic valve insufficiency was not statistically significant(P>0.05).After a median follow-up of 26(14.5,37.5)months,the patients were divided into valve calcification group(including calcification group at baseline and newly developed calcification group)and non-valvular calcification group according to the presence of cardiac valve calcification at the end of follow-up.The cardiac function parameters were compared between the two groups.The results showed that the difference in the left atrium diameter and E/A was statistically significant(P<0.05)between the two groups.The left ventricular diastolic diameter,interventricular septal thickness,left ventricular posterior wall thickness,left ventricular ejection fraction,left ventricular fractional shortening,left ventricular hypertrophy,moderate to severe mitral insufficiency and moderate to severe aortic insufficiency were compared.The difference was not statistically significant(P>0.05).4.Outcome: The proportion of patients undergoing combined dialysis in the calcification group at baseline was higher than that in the non-calcification group.The difference was statistically significant(P<0.05).The difference in continuous peritoneal dialysis,death,converted to hemodialysis and renal transplantation was not statistically significant(P>0.05)between the two groups.The mortality of newly developed calcification group was higher than that of non-newly developed calcification group.The difference was statistically significant(P<0.05).The difference in peritoneal dialysis,combined dialysis,converted to hemodialysis and kidney transplantation was not statistically significant(P>0.05)between the two groups.5.Kaplan-Meier univariate survival analysis showed that the difference in survival rate was not statistically significant(P>0.05)between the calcification group and the non-calcification group at baseline.Difference in survival rate was statistically significant(P < 0.05)between the newly calcification group and the non-new calcification group.Multivariate regression analysis of Cox regression model showed that valve calcification(P=0.036,HR=2.454,95%CI 1.063-5.666)was an independent risk factor for the survival of patients with PD.Conclusion:1.Cardiac valve calcification is more commonly seen in patients with peritoneal dialysis,and aortic valve calcification is more than mitral valve calcification.2.Old age,low albumin and high urea nitrogen are independent risk factors for cardiac valve calcification in patients with uremia before dialysis.Low albumin,high alkaline phosphatase and hypertension are independent risk factors for newly developed cardiac valve calcification in patients with peritoneal dialysis.3.Valve calcification is an independent risk factor that affects the survival of patients with peritoneal dialysis.