RESUMO
OBJECTIVES: Transjugular intrahepatic portosystemic shunt (TIPS) is a catheter-based, minimally invasive procedure to reduce portal hypertension. The aim of the study was to investigate dysfunction and mortality after TIPS and to identify factors associated with these events. METHODS: A retrospective analysis of 834 patients undergoing TIPS implantation in a single center from 1993-2018 was performed. Cumulative incidence curves were estimated, and frailty models were used to assess associations between potentially influential variables and time to dysfunction or death. RESULTS: 1-, 2-, and 5-year mortality rates were 20.9% (confidence interval (CI) 17.7-24.1), 22.5% (CI 19.1-25.8), and 25.0% (CI: 21.1-28.8), 1-year, 2-year, and 5-year dysfunction rates were 28.4% (CI 24.6-32.3), 38.9% (CI 34.5-43.3), and 52.4% (CI 47.2-57.6). The use of covered stents is a protective factor regarding TIPS dysfunction (hazard ratio (HR) 0.47, CI 0.33-0.68) but does not play a major role in survival (HR 0.95, CI 0.58-1.56). Risk factors for mortality are rather TIPS in an emergency setting (HR 2.78, CI 1.19-6.50), a previous TIPS dysfunction (HR 2.43, CI 1.28-4.62), and an increased Freiburg score (HR 1.45, CI 0.93-2.28). CONCLUSION: The use of covered stents is an important protective factor regarding TIPS dysfunction. Whereas previous TIPS dysfunction, emergency TIPS implantation, and an elevated Freiburg score are associated with increased mortality. Awareness of risk factors could contribute to a better selection of patients who may benefit from a TIPS procedure and improve clinical follow-up with regard to early detection of thrombosis/stenosis. CRITICAL RELEVANCE STATEMENT: The use of covered stents reduces the risk of dysfunction after transjugular intrahepatic portosystemic shunt (TIPS). TIPS dysfunction, emergency TIPS placement, and a high Freiburg score are linked to higher mortality rates in TIPS patients. KEY POINTS: The risk of dysfunction is higher for uncovered stents compared to covered stents. Transjugular intrahepatic portosystemic shunt dysfunction increases the risk of instantaneous death after the intervention. A higher Freiburg score increases the rate of death after the intervention. Transjugular intrahepatic portosystemic shunt implantations in emergency settings reduce survival rates.
RESUMO
Metal artifacts notoriously pose significant challenge in computed tomography (CT), leading to inaccuracies in image formation and interpretation. Artifact reduction tools have been designed to improve cone beam computed tomography (CBCT) image quality by reducing artifacts caused by certain high-density materials. Metal artifact reduction (MAR) tools are specific algorithms that are applied during image reconstruction to minimize or eliminate artifacts degrading CBCT images. The purpose of the study is to evaluate the effect of a MAR algorithm on image quality in CBCT performed for evaluating patients before transarterial radioembolization (TARE). We retrospectively included 40 consecutive patients (aged 65 ± 13 years; 23 males) who underwent 45 CBCT examinations (Allura FD 20, XperCT Roll protocol, Philips Healthcare, Best, The Netherlands) in the setting of evaluation for TARE between January 2017 and December 2018. Artifacts caused by coils, catheters, and surgical clips were scored subjectively by four readers on a 5-point scale (1 = artifacts affecting diagnostic information to 5 = no artifacts) using a side-by-side display of uncorrected and MAR-corrected images. In addition, readers scored tumor visibility and vessel discrimination. MAR-corrected images were assigned higher scores, indicating better image quality. The differences between the measurements with and without MAR were most impressive for coils with a mean improvement of 1.6 points (95%CI [1.5 1.8]) on the 5-point likert scale, followed by catheters 1.4 points (95%CI [1.3 1.5]) and clips 0.7 points (95%CI [0.3 1.1]). Improvements for other artifact sources were consistent but relatively small (below 0.25 points on average). Interrater agreement was good to perfect (Kendall's W coefficient = 0.68-0.95) and was higher for MAR-corrected images, indicating that MAR improves diagnostic accuracy. A metal artifact reduction algorithm can improve diagnostic and interventional accuracy of cone beam CT in patients undergoing radioembolization by reducing artifacts caused by diagnostic catheters and coils, lowering interference of metal artifacts with adjacent major structures, and improving tumor visibility.