Correlation of uterine artery Doppler flow velocimetry and β-human chorionic gonadotropin levels during postmolar evacuation surveillance: A pilot study in a tertiary hospital

Abstract

BACKGROUND: During postmolar evacuation surveillance, beta-human chorionic gonadotropin (β-hCG) regression levels can predict invasive disease while Doppler ultrasound can assess in vivo tumor neovascularization and quantify uterine blood supply. As an ancillary tool to β-hCG monitoring, ultrasound can detect the early presence of viable trophoblastic tissues and identify patients at risk of developing postmolar gestational trophoblastic Neoplasia (PMGTN). OBJECTIVE: The objective of this study was to correlate uterine artery Doppler ultrasound with β-hCG levels during pre- and postmolar evacuation surveillance among patients with complete mole. MATERIALS AND METHODS: A cohort of patients with sonographic diagnosis of complete hydatidiform mole and managed with suction curettage in the same institution were prospectively followed up after evacuation. The pre- and postmolar evacuation surveillance period was at days 1, 7, 14, 21, 28, and 35. Monitoring of serum β-hCG levels was based on the standard regression curve. For Doppler ultrasound parameters, monitoring of the systolic/diastolic (S/D) ratio, pulsatility index (PI), resistance index (RI), and peak systolic velocity (PSV) was based on its relationship with its serum β-hCG levels. The ultrasound images generated were archived and reviewed by the authors. Descriptive and inferential statistics were utilized to analyze median differences. For the correlation of uterine artery Doppler flow parameters, analysis for the test of difference used Pearson correlation and multiple linear regression analysis for the odds ratio. RESULTS: Sixteen of the 23 enrolled patients completed the protocol (16 of 23, 69.50%). A majority had spontaneous remission (13; 81%) while 3 cases (19%) presented increasing and plateauing β-hCG levels. The pre- and post evacuation median β-hCG levels showed a significant decrease (P = 0.001). As post evacuation β-hCG levels decreased, PSV also decreased (r = 0.478, P = 0.061) while Doppler parameters, RI, PI, and S/D ratio increased. However, when post evacuation β-hCG levels rose or plateaued, Doppler parameters decreased. These changes had statistical correlation (all P < 0.05). Moreover, the magnitude of the relationship for β-hCG and Doppler parameters was moderate and ranged from 0.524 to 0.581. Among the Doppler parameters, the S/D ratio and RI of the right uterine artery strongly predicted a rise in β-hCG levels. The odds ratio of predicting increased β-hCG levels and risk of gestational trophoblastic neoplasia by the right S/D ratio were − 2683.67 (confidence interval [CI] = −271.692–5095.655; P = 0.034) and by the right RI − 66,193.34 (CI = −161,818.107–29,431.433; P = 0.046). Notably, Doppler parameter changes appeared early at day 14 up to day 35 and before the appearance of abnormal β-hCG regression patterns. CONCLUSION: There is a strong correlation between uterine artery Doppler flow changes and β-hCG levels during postmolar evacuation surveillance. The inverse relationship of the S/D ratio, PI and RI, and β-hCG regression patterns confirms spontaneous remission of the disease. For patients with abnormal β-hCG patterns, this relationship is altered. The Doppler changes become erratic, unpredictable, and significantly decreased. These changes were detected as early as 2 weeks post evacuation. Thus, the use of ultrasound as an adjunct to β-hCG post evacuation surveillance can predict abnormal β-hCG regression patterns and identify patients at risk of developing postmolar gestational trophoblastic neoplasia (PMGTN).