CT-guided transfemoral portocaval shunt creation

Intrahepatic arterial localizer guided transjugular intrahepatic portosystemic shunt placement: Feasibility, efficacy, and technical success assessed by a case series-a STROBE- compliant article

Transjugular intra-hepatic portosystemic shunts (TIPS) had been considered a standard procedure in patients suffering from portal hypertension. The most challenging step in TIPS placement is blind puncture of the portal vein. We had established a localization method by introducing an Intra-Hepatic Arterial based puncture directing Localizer (IHAL) with the assistance of the enhanced computed tomography (CT) reconstruction. This study aimed to evaluate the feasibility, efficacy, and technical success of this method.From June 2018 to August 2018, 10 consecutive patients suffering from refractory ascites or esophageal gastric bleeding by liver cirrhosis were included in this retrospective study to evaluate feasibility, efficacy, and technical success of enhanced CT assisted IHAL-guided puncture of the portal vein. As a control, 10 patients receiving TIPS placement before Jun 2018 with cone beam CT (CBCT)-guided puncture were included to compare the reduction of portal-systemic pressure gradient (PSPG), portal entry time (PET), the number of puncture, dose area product (DAP) and contrast medium consumption.Technical success was 100% in the study group (IHAL-guided group) and in 90.0% of the control group (CBCT-guided group). Appropriate IHAL point could be achieved in all patients under the enhanced CT reconstruction assistance. The median number of punctures and DAP in IHAL group were significantly less than those in CBCT group. The reduction of PSPG, PET, and contrast medium consumption in IHAL group showed no significant differences than those in CBCT group.Enhanced CT reconstruction assisted IHAL-guided portal vein puncture is technically feasible and a reliable tool for TIPS placement resulting in a significant reduction of the number of punctures and DAP.

Three-dimensional C-arm CT-guided transjugular intrahepatic portosystemic shunt placement: Feasibility, technical success and procedural time

OBJECTIVES

Establishment of transjugular intrahepatic portosystemic shunts (TIPS) constitutes a standard procedure in patients suffering from portal hypertension. The most difficult step in TIPS placement is blind puncture of the portal vein. This study aimed to evaluate three-dimensional mapping of portal vein branches and targeted puncture of the portal vein.

METHODS

Twelve consecutive patients suffering from refractory ascites by liver cirrhosis were included in this retrospective study to evaluate feasibility, technical success and procedural time of C-arm CT-targeted puncture of the portal vein. As a control, 22 patients receiving TIPS placement with fluoroscopy-guided blind puncture were included to compare procedural time.

RESULTS

Technical success could be obtained in 100 % of the study group (targeted puncture) and in 95.5 % of the control group (blind puncture). Appropriate, three-dimensional C-arm CT-guided mapping of the portal vein branches could be achieved in all patients. The median number of punctures in the C-arm CT-guided study group was 2 ± 1.3 punctures. Procedural time was significantly lower in the study group (14.8 ± 8.2 min) compared to the control group (32.6 ± 22.7 min) (p = 0.02).

CONCLUSIONS

C-arm CT-guided portal vein mapping is technically feasible and a promising tool for TIPS placement resulting in a significant reduction of procedural time.

KEY POINTS

• C-arm CT-mapping of the portal vein for 3D TIPS guidance is feasible. • Targeted punctures of the portal vein by C-arm CT reduce procedural time. • A decreased number of punctures could improve patient safety.

Novel Image Guidance Techniques for Portal Vein Targeting During Transjugular Intrahepatic Portosystemic Shunt Creation

The most challenging part of transjugular intrahepatic portosystemic shunt creation is arguably the transvenous access from the hepatic vein to the portal vein. As experience and technology have evolved, the image guidance aspect of this critical step in the procedure has become more robust. Improved means to target the portal vein include both direct and indirect methods of portal vein opacification, cross-sectional imaging for both targeting and access, and novel use of transabdominal and intravascular ultrasound guidance. These techniques are described herein.

Transjugular intrahepatic portosystemic shunt creation using intravascular ultrasound guidance

PURPOSE

To describe the use of intravascular ultrasound (US) guidance for creation of transjugular intrahepatic portosystemic shunts (TIPSs) in humans.

MATERIALS AND METHODS

The initial 25 cases of intravascular US-guided TIPS were retrospectively compared versus the last 75 conventional TIPS cases during the same time period at the same institution in terms of the number of needle passes required to establish portal vein (PV) access, fluoroscopy time, and needle pass-related complications.

RESULTS

Intravascular US-guided TIPS creation was successful in all cases, and there was no statistically significant difference in number of needle passes, fluoroscopy time, or needle pass-related complications between TIPS techniques. Intravascular US-guided TIPS creation was successful in cases in which conventional TIPS creation had failed as a result of PV thrombosis or distorted anatomy. Intravascular US guidance for TIPS creation was additionally useful in a patient with Budd-Chiari syndrome and in a patient with intrahepatic tumors.

CONCLUSIONS

Intravascular US is a safe and reproducible means of real-time image guidance for TIPS creation, equivalent in efficacy to conventional fluoroscopic guidance. Real-time sonographic guidance with intravascular US may prove advantageous for cases in which there is PV thrombus, distorted anatomy, Budd-Chiari syndrome, or hepatic tumors.

Implementation of an electromagnetic tracking system for accurate intrahepatic puncture needle guidance: accuracy results in an in vitro model

RATIONALE AND OBJECTIVES

Electromagnetic tracking potentially may be used to guide percutaneous needle-based interventional procedures. The accuracy of electromagnetic guided-needle puncture procedures has not been specifically characterized. This article reports the functional accuracy of a needle guidance system featuring real-time tracking of respiratory-related target motion.

MATERIALS AND METHODS

A needle puncture algorithm based on a "free-hand" needle puncture technique for percutaneous intrahepatic portocaval systemic shunt was employed. Preoperatively obtained computed tomographic images were displayed on a graphical user interface and registered with the electromagnetically tracked needle position. The system and procedure was tested on an abdominal torso phantom containing a liver model mounted on a motor-driven platform to simulate respiratory excursion. The liver model featured two hollow tubes to simulate intrahepatic vessels. Registration and respiratory motion tracking was performed using four skin fiducials and a needle fiducial within the liver. Success rates for 15 attempts at simultaneous puncture of the two "vessels" of different luminal diameters guided by the electromagnetic tracking system were recorded.

RESULTS

Successful "vessel" puncture occurred in 0%, 33%, and 53% of attempts for 3-, 5-, and 7-mm diameter "vessels," respectively. Using a two-dimensional accuracy prediction analysis, predicted accuracy exceeded actual puncture accuracy by 25%-35% for all vessel diameters. Accuracy outcome improved when depth-only errors were omitted from the analysis.

CONCLUSIONS

Actual puncture success rate approximates predicted rates for target vessels 5 mm in diameter or greater when depth errors are excluded. Greater accuracy for smaller diameter vessels would be desirable for implementation in a broader range of clinical applications.

Simplified Technique for Percutaneous Transrenal Arteriovenous Dialysis Graft Creation in a Swine Model

PURPOSE

To investigate the experimental creation of a percutaneous arteriovenous graft via the renal vessels using a simplified technique and to report on its safety, complications, and 1-month follow-up.

MATERIALS AND METHODS

Transrenal arteriovenous grafts were created from the renal artery to the renal vein in six swine. Using a combined transfemoral and percutaneous approach, a 7 mm x 150 mm stent graft was deployed to create a renal vein limb, and a 6 mm x 150 mm stent graft was deployed to form the renal artery limb. The external portion of the arterial limb was telescoped into the venous limb to form one continuous loop and was placed into a subcutaneous pocket. The duration and technical success of the procedure were recorded. Shunt patency was assessed by auscultation and angiography, as well as by necropsy and histopathology.

RESULTS

Arteriovenous graft creation was technically successful in all six animals with rapid arteriovenous shunting documented with angiography at completion. The mean procedure duration was 84 minutes (range, 70-130 minutes). Auscultation and angiography revealed that four of the six shunts were occluded at 4 weeks. Moderate (50% to 75%) diffuse in-stent angiographic stenosis was present in the two remaining animals. No technical complications occurred. Midterm complications of localized and gradual concentric stenosis due to mural thrombosis occurred in three animals. Graft infection resulting in late abrupt thrombosis occurred in four animals.

CONCLUSIONS

Transrenal arteriovenous graft creation using the simplified technique can be performed safely in swine. Delayed complications including graft infection and in-stent stenosis must be addressed prior to use of the technique in clinical settings.

Transjugular Intrahepatic Portosystemic Shunt in a Living Donor Left Lateral Segment Liver Transplant Recipient: Technical Considerations

The technical aspects of placing transjugular intrahepatic portosystemic shunts (TIPS) in liver transplant recipients with full allografts have well been described. In the era of live related hepatic donors, and the growing population of their recipients, it is likely that TIPS shunts will be placed in failing transplant lobes/segments. Growing allografts that are initially undersized can have an unconventional orientation of the hepatic and portal veins, which may also change with remodeling and rotation of the graft during their growth. The authors review the technical differences for TIPS procedures in transplants, particularly split grafts. They describe a technically successful TIPS procedure in an undersized and remodeled left lateral segment liver recipient and the additional difficulty this may pose.

Transrenal arteriovenous dialysis graft creation: survival and patency in a swine model

PURPOSE

To investigate transrenal arteriovenous graft creation in an animal model and to report survival and patency.

MATERIALS AND METHODS

Arteriovenous grafts were created from the renal artery to the renal vein in 10 swine. Renal access was accomplished with a combined percutaneous and transvascular approach. A reinforced 6-mm polytetrafluoroethylene conduit was tunneled between both flank access points, and stent-grafts were deployed from each of the renal origins into the conduit. Clopidogrel (10 mg per kilogram of body weight) was administered intravenously during the procedure, followed by a daily oral dose (75 mg) for up to 2 weeks. Animals were monitored with auscultation and angiography for up to 1 month; necropsy was performed in all animals.

RESULTS

Rapid arteriovenous flow at completion angiography was achieved in eight of 10 animals. Shunts were patent in five of six animals that were followed for 1 month. Diffuse pseudointimal hyperplasia was mild in three of six shunts and moderate in two (focal stenoses). Immediate thrombosis occurred in the first two animals when the clopidogrel bolus was administered after stent-graft deployment. These shunts were recanalized mechanically. Shunts were immediately patent in five of the six remaining shunts when the clopidogrel bolus was administered prior to stent-graft deployment. Complications occurred in four of 10 animals, three of which were euthanized within 1 week. The bowel was traversed in two animals, and renal vein laceration occurred during two procedures because of failure of the stent-graft delivery system.

CONCLUSION

Transrenal arteriovenous graft creation in swine is technically feasible, and long-term patency is possible with antiplatelet therapy.