Clinical Application of a New Cesarean Scar Pregnancy Classification and Evaluation System and a Risk Scoring System

Abstract

Objective: Cesarean scar pregnancy (CSP) is an uncommon form of ectopic pregnancy that carries the risk of severe bleeding. To date, there has not been a universally accepted classification and treatment strategy. We performed this study to establish a risk scoring system and new CSP classification system for CSP and evaluate its efficacy.

Methods: A total of five groups were generated based on different methods of treatment, and the factors that increase the risk of intraoperative bleeding were examined in our center from 2013 to 2018. The construction of a risk scoring system in this study was based on the use of the chi-square test and multivariate logistic regression analysis. To determine the appropriate cutoff scores, receiver operating characteristic (ROC) curves and the area under the curve (AUC) were generated.

Results: We identified the main high-risk factors for excessive intraoperative hemorrhage during CSP surgery through univariate and multivariate analyses. Within this investigation, the risk factors included gestational sac location and gestational sac diameter. Through analysis, an optimal cutoff score of 3 was determined, and the area under the ROC curve was calculated to be 0.8113 (95% CI=0.7696-0.8531). A score ranging from 0-3 was classified as low risk, while a score ranging from 5-7 was classified as high risk. Additionally, a new classification system for CSP has been established based on sonographic parameters. We also established a diagnostic and treatment process for CSP patients according to the risk scoring method and new CSP classification.

Conclusion: We identified the high-risk factors associated with bleeding during CSP surgery and developed a scoring system incorporating these factors. The utilization of this novel CSP typing method, in conjunction with the risk scoring system, can effectively inform doctors in their decision-making process concerning treatment strategies for patients with CSP.

Keywords: cesarean scar pregnancy; classification; risk; scoring system; treatment.

Figure 1

The goodness of fit of the model was assessed through the utilization of the Hosmer–Lemeshow test for model fitting validation. Following the establishment of the scoring model, the HL test was employed to ascertain the stability of the model and verify its fit. The obtained p value of 0.9418 suggested that the model performed satisfactorily in terms of both prediction and fitting. Furthermore, the majority of the data points (represented by blue points) align closely with the diagonal line, indicating a favorable fit for the model.

Figure 2

The validation of the risk scoring system was assessed through the estimation of the ROC curve. The evaluation employing tenfold crossover validation yielded an AUC of 0.8077. The area under the ROC curve was determined to be 0.8113, with a 95% confidence interval ranging from 0.7696 to 0.8531. A threshold of 3 was identified as the optimal cutoff.

Figure 3

Diagrams of different CSP types and their corresponding Doppler ultrasound characteristics. CSP can be divided into three types: closer type (type I), implantation type (type II) and infiltration type (type III). (A) Closer type (type Ia and type Ib). (B) Implantation type: implantation IIa (thickness ≥ 0.2 cm) and implantation IIb (0.1 cm ≤ thickness < 0.2 cm). (C) Infiltration type: type IIIa (thickness < 0.1 cm) and type IIIb (mass type). (D–F) Ultrasound characteristics of CSP corresponding to different subtypes.

Figure 4

The various treatment strategies were scored differently, and the frequencies corresponding to their scores and classifications differed. (A) Observations were made on the proportion of high-risk and low-risk patients across five distinct surgical methods, as well as their overall scores. The frequencies of surgical procedures were measured using different methods, including the risk scoring system (B) and ultrasound imaging, to determine the type of CSP (C).

Figure 5

CSP diagnosis and treatment flowchart. The patient’s risk score and classification were determined based on the size and location of the gestational sac, followed by the adoption of treatment strategies corresponding to different scores and subtypes.