The Analysis Of The High-risk Factors For Failed Hysteroscopic Treatment Of Cesarean Scar Pregnancy And Building Risk Scoring System

Objective:To discuss the specific indications of hysteroscopic treatment of cesarean scar pregnancy(CSP)by studying the high-risk factors for failed hysteroscopic treatment of cesarean scar pregnancy,to help improve the preoperative evaluation of hysteroscopy in the treatment of cesarean scar pregnancy,and reduce the risk of failure.Methods:112 cesarean scar pregnancy patients admitted in Qingdao Municipal hospital from Jun.2013 to Oct.2018 who received hysteroscopic treatment were analyzed retrospectively.They were divided into two groups by the result of hysteroscopic surgery:(1)the successful group(2)the failed group.In single-variable statistical analysis,some factors were compared between these two groups by using Student’s t-test,Mann-Whitney U-test orχ~2 test,including patients’symptoms(vaginal bleeding,abdominal pain),age,gravidity,parity,times of cesarean sections,abortion,the interval between the current CSP and last cesarean section,gestational age,the level ofβ-HCG,diameter of gestational sac,thickness between gestational sac or mass and bladder,the blood perfusion around cesarean scar(PSV and RI value),presence of fetal cardiac.Therefore,statistically significant factors were obtained.Then draw the receiver operating characteristic curve and get the optimal cut-off.On multivariable logistic regression analysis,most variables were divided into two categories.Each factor was dichotomized by the optimal cut-off.Finally,independent risk factors with p<0.05 were identified.The scoring risk system for cesarean scar pregnancy was built by the independent risk factors’odds ratio(OR).Results:In single-variable statistical analysis the failure group had higher gestational age,higher serumβ-HCG level,larger CSP mass,thinner myometrial layer between the bladder and the sac,higher PSV value,and lower RI value compared with the control group(P﹤0.05).(1)The receiver operating characteristic curve of every risk factor was drawn.And the area under the curve(AUC)of each risk factor’s ROC including gestational age,serumβ-HCG,diameter of gestational sac,thickness of myometrial layer between the bladder and the sac,PSV value,and RI value was 0.941,0.663,0.805,0.921,0.952,0.917 respectively.The optimal cut-off on each ROC was 55days,30737mIU/ml,3.3cm,0.29cm,57.5cm/s,0.385 respectively,the sensitivity of each ROC was93.8%,86.1%,81.3%,87.5%,93.8%,93.8%respectively,and the specificity was 89.6%,46.9%,66.7%,81.2%,88.5%,81.2%.(2)On multivariable logistic regression analysis,the independent risk factors were gestational age≥55 days(OR9.976,95%CI(1.296~76.814),P=0.027),diameter of gestational sac≥3.3cm(OR41.624,95%CI(3.683~470.445),P=0.003),thickness of myometrial layer between the bladder and the sac≤0.29cm(OR10.953,95%CI(1.320~90.867),P=0.027),PSV≥57.5cm/s(OR32.024,95%CI(3.565~287.644),P=0.002),RI≤0.385(OR36.489,95%CI(2.804~474.834),P=0.006),while the independent risk factors did not include the serumβ-HCG level≥30737mIU/ml(OR1.083,95%CI(0.118~9.960),P=0.944).(3)A total of 7.5 points was identified as the optimal cut-off on the ROC curve of the final risk scoring system and it had an AUC of 0.973,sensitivity of 93.8%and specificity of 91.7%.Conclusion:(1)The independent risk factors for failed hysteroscopic treatment of cesarean scar pregnancy include gestational age,diameter of gestational sac,thickness of myometrial layer between the bladder and the sac,and the blood perfusion around the cesarean scar(PSV and RI value).(2)When the CSP patient had gestational age≥55 days,diameter of gestational sac or mass≥3.3cm,thickness of myometrial layer between the bladder and the sac≤0.29cm,PSV≥57.5cm/s and RI≤0.385,the risk of failed hysteroscopic treatment was high.(3)In the terms of the final risk scoring system,hysteroscopic treatment can be the first choice for CSP patients whose total scores are less than 7 points.When patient’s total scores are more than 8 points,preoperative uterine artery embolism can be done or other treatment strategy should be selected.When patient’s total scores are more than 11 points,hysteroscopic treatment should be not recommended.(4)For the CSP patients whose total scores are very high but insist on choosing hysteroscopic treatment,it is necessary to make full preparations in case of changing the surgical method.At the same time,preoperative evaluation should be fully carried out before the operation,so as to facilitate timely decision-making after hysteroscopy failure.