The Value Of Multi-slice Computed Tomography In Prediction Of Mortality Risk And Evaluation Of Pulmonary Arteries Development After Central Shunt

BackgroundCentral shunt(CS)is one of the important palliative operations for complex congenital heart diseases with decreased pulmonary blood flow(CCHDs-DPBF),which aims to improve hypoxia and promote the development of pulmonary arteries(PAs).However,the mortality of CS is high,and the factors relating to mortality and PAs growth after CS are not completely clear.Morphological assessment by cardiac computed tomography angiography(CTA)may contribute to predicting the postoperative outcomes after CS.Purpose1.To investigate the risk predictors of postoperative mortality after CS in patients with CCHDs-DPBF based on preoperative cardiac CTA;2.To assess the development of PAs and its influencing factors after CS in patients with CCHDs-DPBF by preoperative and postoperative cardiac CTA.Materials and Methods1.95 patients who underwent CS with preoperative cardiac CTA were enrolled retrospectively.The end-point was defined as death from any cause before next-stage surgery.Logistic regression analysis and Cox proportional hazards model were used to evaluate the risk factors of 30-day mortality and overall mortality(before next-stage surgery)after CS,including the basic characteristics of patients,the morphological parameters of cardiac CTA and the surgical data.2.Among 95 patients mentioned above,50 patients who underwent CS with preoperative and postoperative(before next-stage surgery)CTA were collected retrospectively.The area of left pulmonary artery(LPA)and right pulmonary artery(RPA)just before their bifurcation was measured on the preoperative and postoperative CTA images,the normalized area was calculated by the body surface area(BSA)to calculate the normalized PAs index change.And the development of PAs was evaluated by Wilcoxon paired test.Combined with the basic characteristics of patients,the morphological parameters of CTA and the surgical data,a stepwise multiple linear regression analysis was performed to assess factors associated with the change of Nakata index.Results1.The median age and weight were 232 days(IQR:74 days,3.5 years)and 7.0(1QR:4.2,11.0)kg,respectively.During a median follow-up of 345 days,a total of 25 deaths were observed,the 30-day mortality was 13.7%and the overall mortality rate was 26.3%.Multivariate analysis showed that patients with preoperative Nakata index>139mm2/m2[Hazard ratio(HR)=12.46,P=0.002)],no postoperative patent ductus arteriosus(PDA)/major aortopulmonary collateral arteries(MAPCAs)(HR=10.54,P=0.032)had a higher likelihood of death within 30 days after CS.Functional single ventricle(HR=3.00,P=0.034),preoperative Nakata index>130mm2/m2(HR=:5.46,P<0.01)and no postoperative PDA/MAPCAs(HR=5.25,P=0.002)were independent risk factors for overall mortality.The area under the receiver-operating characteristic curve for Nakata index was 0.75,and a cut-off point of 130 mm2/m2 was deemed the significant threshold for survival(sensitivity 68%,specificity 77%).2.Of the 50 patients with CTA before and after CS,during the follow-up of 380 days,4 patients had no pulmonary artery development,the overall Nakata index of the remaining 46 patients increased from 84.76(IQR:54.43,117.32)mm2/m2 to 209.31(IQR:129.63,307.16)mm2/m2(P<0.001).LPA index increased from 39.23(IQR:24.25,52.04)mm2/m2 to 104.41(IQR:55.69,136.81)mm2/m2(P<0.001),RPA index increased from 38.36(IQR:24.36,57.39)mm2/m2 to 99.30(IQR:58.67,173.59)mm2/m2(P<0.001).There was no significant difference in the index change between LPA and RPA(P =0.160).Postoperative CTA images showed 24 cases of shunt stenosis,of which 13 cases were mild(<50%),I11 cases were severe(>50%),including 4 cases of complete occlusion.Large shunt diameter/BSA(P<0.001),postoperative residual PDA(P =0.041)and no severe shunt stenosis(P=0.003)were beneficial to the increase of Nakata index after CS.Conclusions1.These morphological parameters based on preoperative cardiac CTA have the potential to predict the risk of death after CS.Preoperative Nakata index>130mm2/m2,FSV and no postoperative PDA/MAPCAs after CS may be predictors of mortality after CS;2.Cardiac CTA can be used to evaluate the development of PAs after CS.CS can promote the balanced development of PAs.More pulmonary blood flow can help promote the gro.Awth of PAs.