Prospective evaluation of post-interventional passive expansion of partially dilated transjugular intrahepatic portosystemic shunt (TIPS) stents – A 3D-sonography study

Aim: To prospectively investigate early expansion kinetics of underdilated self-expanding Viatorr stent-grafts used for TIPS-creation within the first six weeks after intervention.

Materials and methods: Patients undergoing TIPS-creation with underdilatation of 10 mm Viatorrstent-grafts, received 2D- and 3D-sonography examinations immediately after TIPS-creation, one and six weeks later. Using a commercially available 3D-transducer volume data sets were generated in longitudinal direction of the stent. Orthogonal views of the TIPS within the parenchymal tract were reconstructed from 3D-data. Reconstructed 3D- and primary 2D-images were used for blinded stent diameter measurements. The measurement technique was validated with intra-interventional plain-radiographic images with a sizing-catheter within the stent as the gold-standard.

Stent diameter changes over time and interrelations with individual patient characteristics were analyzed using a general linear model for repeated measures.

Results: 20 patients (7 female; mean age 66; range 31 – 80) with liver cirrhosis (etiology: 14 alcoholic, 2 hepatitis, 4 other) were included. Indications for TIPS were variceal bleeding in 5, refractory ascites in 14 and for both indications in 1 patient. After dilatation to a diameter of 8 mm, 3D-measurements showed an initial stent-recoil to a mean diameter of 7.6 mm (± 0.17 standard deviation [SD]). The diameter of TIPS increased to 8.7 mm (± 0.27SD) and 9.4 mm (± 0.11SD), one and six weeks later respectively (p < 0.001). 2D-measurements showed comparable results. Validation measurements showed no significant differences between 2D- or 3D-sonography and the gold-standard. There were no statistically significant associations of stent expansion with clinical parameters. Stent expansion occurred less in patients of higher liver-stiffness measured by Shear-wave elastography in the subgroup of patients with alcoholic liver disease.

Conclusion: Underdilated self-expanding Viatorr stent-grafts used for TIPS-creation significantly expand already within the first 6 weeks after intervention. 3D-sonography might be useful to monitor these changes non-invasively.