Exploring The Minium Z Value Of Preserving Pulmonary Valve Annulus In Corrective Operation Of Tetralogy Of Fallot (TOF)

OBJECTIVE:A large number of clinical studies have shown that the long-term outcome of preserving pulmonary valve annulus is superior to insert trans-annulus patch(TAP)in corrective operation of Tetralogy of Fallot(TOF).Therefore,In addition to reliefing the right ventricular outflow tract obstruction(ROVTO),the physiological function and potential growth of PVA should be preserved as much as possible,which is recognized by the majority of cardiac surgeons.However,there is no standard for the optimal Z Value of preserving pulmonary valve annulus(PVA).This study aimed to explore the relationship between preoperative Z Value and preserving PVA.METHODS:This is a retrospective study of 407 patients with corrective surgery of TOF performed during the period between January 2012-01-01 and 2018-12-12 in our hospital,including the right ventricular double outlet(DORY)of TOF type.All enrolled cases strictly followed the inclusion and exclusion criteria and the standard of the surgeon.Inclusion criteria:age<18 years;diagnosized TOF or DORY of TOF type;no surgical contraindications;exclusion criteria:age>18 years;DORV of not TOF type and PA;surgical contraindications;combined with other complex cardiac malformations.Standard of the surgeon:The three main surgeons have been engaged in more than 10 years of experience in children's cardiac surgery,and have completed more than 100 cases of TOF surgery.Using the ROC curve to explore the critical value of inserting trans-annulus patch(TAP)by using SPSS 20.0 software,and continue to group according to the Z Value threshold for comparison;Correctting preoperative parameters and determining observation indicators;using Kolmogorov-Smirnov test to analyse whether continuous variables for normal distribution;using independent sample T test to analyse normal distribution variables;using non-parametric Mann-Whitney test to analyse non-normal distribution variables;using chi-square test analyse categorical variables;P<0.05 was statistically different.RESULTS:1.Using the ROC curve and the Yoden index method,explore the relationship between Preoperative Z Value and preserving pulmonary valve annulus.and obtain the critical Z Value:Z=-2.65.2.The prognosis such as PR ratio.ICU time(h),ventilator assistant time(h),and postoperative hospital time(d)between the PVA-reserved group and the trans-annulus group were statistically significant(P<0.0001),that is,the PVA-reserved group is better than the trans-annulus group.3.When Z Value>-2.65,70.54%preserves PVA.The prognosis between the PVA-reserved group and the trans-annulus group was statistically significant(p<0.0001).PR ratio,ICU time(h),ventilator assistant time(h),and postoperative hospital time(d).PVA-reserved group is better than trans-annulus group.4.When Z Value<-2.65,only 26 cases(14.21%)PVA-reserved.The prognosis such as PR ratio,ICU time(h),ventilator assistant time(h)and postoperative hospital time(d)between the PVA-reserved group and the trans-annulus group was statistically significant(P<0.0001),that is,the PVA-reserved group is better than trans-annulus group.CONCLUSION:1.The critical point of Z value to insert TAP is "-2.65".If Z<-2.65,we tend to insert TAP;If Z>-2.65,we tend to preserve the PVA.2.The prognosis of PVA-reserved group were better than the trans-annulus group of the overall 407 patients;the prognosis of PVA-reserved group was better than the trans-annulus group in both"Z<-2.65"and"Z>-2.65”.3.It can be considered that the criterion of'Z=-2.65" is safe for preserving PVA,but may be conservative.Therefore,it is necessary to explore more optimal Z Value by larger sample and technology advancement in the future.