Pediatric liver transplant portal vein anastomotic stenosis: a comparative study between Doppler ultrasound and intravascular manometry / 中华超声影像学杂志

ABSTRACT

Objective:To investigate the correlation between Doppler ultrasound parameters and pressure gradient of portal vein in pediatric liver transplant patients, and to analyze the diagnostic value of Doppler ultrasound for portal vein stenosis.Methods:This retrospective study involved the data from 92 pediatric liver transplant patients in Tianjin First Central Hospital from June 2014 to September 2021, who underwent pressure gradient measurement. The collected ultrasonic parameters included the diameter and flow velocity of the native portal vein, the portal vein anastomosis, and the donor portal vein. The anastomotic stenosis rate=(the native portal vein diameter–the portal vein anastomosis diameter)/the native portal vein diameter, the velocity ratio=the portal vein anastomosis velocity /the native portal vein velocity, the velocity difference=the portal vein anastomosis velocity–the native portal vein velocity. According to the diagnostic standard of portal vein stenosis, pressure gradient more than 5 mmHg was the portal vein stenosis group, and the pressure gradient less than 5 mmHg was the non-stenosis group. The correlation and differences between ultrasonic parameters and pressure gradient were analyzed. ROC curve was used to evaluate the diagnostic efficiency of each parameter.Results:Firstly, there was a positive correlation between pressure gradient and the portal vein anastomosis velocity, the velocity difference and the velocity ratio ( r=0.521, 0.531, 0.417; all P<0.001). And there was a negative correlation between pressure gradient and the anastomotic diameter ( r=-0.284, P=0.004). Secondly, the portal vein anastomotic velocity, velocity difference and velocity ratio in stenosis group were significantly higher than those in non-stenosis group [135.5(111.0, 169.0)cm/s vs 103.7(72.9, 118.7)cm/s, (112.2±40.3)cm/s vs (67.9±30.5)cm/s, 5.56(3.73, 7.26) vs 3.85(2.78, 4.70); all P≤0.001]; Furthermore, by ROC curve analysis, the cut-off value, the area under the ROC curve, Jordan index, accuracy, sensitivity and specificity of each parameter for the diagnosis of portal vein stenosis were the anastomotic velocity 124.5 cm/s, 0.814, 0.592, 80.0%, 65.5% and 93.7%; velocity ratio 5.67, 0.760, 0.488, 73.0%, 48.8% and 100%; velocity difference 107.25 cm/s, 0.797, 0.511, 76.0%, 51.9% and 100%. Conclusions:The anastomosis velocity, velocity difference and velocity ratio of portal vein in pediatric liver transplant patients are correlated with the pressure gradient, and there is higher accuracy and specificity of each parameter for diagnosing portal vein stenosis, but the sensitivity is slightly lower.