Use of CT-guided marking of the portal vein in creation of 150 transjugular intrahepatic portosystemic shunts

t-PA power-pulse spray with rheolytic mechanical thrombectomy using cross-sectional image-guided portal vein access for single setting treatment of subacute superior mesenteric vein thrombosis

Background:

Isolated superior mesenteric vein (SMV) thrombosis is a rare but potentially fatal condition if untreated. Current treatments include transjugular or transhepatic approaches for rheolytic mechanical thrombectomy and subsequent infusions of thrombolytics. Tissue plasminogen activator (t-PA) power-pulse spray can provide benefit in a single setting without thrombolytic infusions. Computed tomography (CT) guidance for portal vein access is underutilized in this setting.

Materials and Methods:

Case 1 discusses acute SMV thrombosis treated with rheolytic mechanical thrombectomy alone using ultrasound guidance for portal vein access. Case 2 discusses subacute SMV thrombosis treated with the addition of t-PA power-pulse spray to the rheolytic mechanical thrombectomy, using CT guidance for portal vein access.

Results:

With rheolytic mechanical thrombectomy alone, the patient in Case 1 had significant improvement in abdominal pain. Follow-up CT demonstrated no residual SMV thrombosis and the patient continued to do well in long-term follow-up. With the addition of t-PA power-pulse spray to rheolytic mechanical thrombectomy, the patient in Case 2 with subacute SMV thrombosis dramatically improved postprocedure with resolution of abdominal pain. Follow-up imaging demonstrated patency to the SMV and partial resolution of thrombus. The patient continued to do well at 2-year follow-up.

Conclusions:

Adding t-PA power-pulse spray to rheolytic mechanical thrombectomy can provide benefit in a single setting versus mechanical thrombectomy alone and prevent the need for subsequent infusions of thrombolytic therapy. CT guidance is a useful alternative of localization for portal vein access via the transhepatic route that is nonoperator-dependent and helpful in the case of obese patients.

Transjugular intrahepatic porto-systemic shunt in the elderly: Palliation for complications of portal hypertension

AIM

To present a dedicated series of transjugular intrahepatic porto-systemic shunts (TIPS) in the elderly since data is sparse on this population group.

METHODS

A retrospective review was performed of patients at least 65 years of age who underwent TIPS at our institutions between 1997 and 2010. Twenty-five patients were referred for TIPS. We deemed that 2 patients were not considered appropriate candidates due to their markedly advanced liver disease. Of the 23 patients suitable for TIPS, the indications for TIPS placement was portal hypertension complicated by refractory ascites alone (n = 9), hepatic hydrothorax alone (n = 2), refractory ascites and hydrothorax (n = 1), gastrointestinal bleeding alone (n = 8), gastrointestinal bleeding and ascites (n = 3).

RESULTS

Of these 23 attempted TIPS procedure patients, 21 patients had technically successful TIPS procedures. A total of 29 out of 32 TIPS procedures including revisions were successful in 21 patients with a mean age of 72.1 years (range 65-82 years). Three of the procedures were unsuccessful attempts at TIPS and 8 procedures were successful revisions of our existing TIPS. Sixteen of 21 patients who underwent successful TIPS (excluding 5 patients lost to follow-up) were followed for a mean of 14.7 mo. Ascites and/or hydrothorax was controlled following technically successful procedures in 12 of 13 patients. Bleeding was controlled following technically successful procedures in 10 out of 11 patients.

CONCLUSION

We have demonstrated that TIPS is an effective procedure to control refractory complications of portal hypertension in elderly patients.

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.

Transjugular Intrahepatic Portosystemic Shunt Creation in Budd-Chiari Syndrome: Percutaneous Ultrasound-Guided Direct Simultaneous Puncture of the Portal Vein and Vena Cava

Budd-Chiari syndrome (BCS) is an uncommon disorder that can be life-threatening, depending on the degree of hepatic venous outflow obstruction. Transjugular intrahepatic portosystemic shunt (TIPS) provides decompression of the congested liver but the hepatic vein obstruction makes the procedure more difficult. We describe a modified method that involved a single percutaneous puncture of the portal vein and inferior vena cava simultaneously for TIPS creation in a patient with BCS.

Transjugular Intrahepatic Portosystemic Shunt Placement in Liver Transplant Recipients: Experiences with Pediatric and Adult Patients

OBJECTIVE

The purpose of our study was to evaluate the safety and efficacy of transjugular intrahepatic portosystemic shunts (TIPS) in pediatric and adult liver transplant recipients. A retrospective review of six TIPS placed in six liver transplant recipients-a pediatric patient with a split liver transplant, a pediatric patient with left lateral segment transplant, and four adult patients-was performed.

CONCLUSION

TIPS placement in both pediatric and adult liver transplant recipients is feasible. In liver transplant patients who are recipients of a left lateral segment or a split liver transplant, knowledge of the liver transplant anatomy is critical in the placement of TIPS. TIPS placement is a treatment option and a bridge to retransplantation for patients who have undergone liver transplantation and develop sequelae of portal hypertension.

CT-guided transfemoral portocaval shunt creation

A patient with superior vena cava (SVC) occlusion presented with severe ascites and urgent transjugular intrahepatic portosystemic shunt (TIPS) was requested. The patient had a chronically occluded SVC. An alternative to classic TIPS was employed using CT guidance to traverse the left portal vein to the inferior vena cava with a small gauge needle. Fluoroscopic guidance was then used to snare a wire placed through the needle and then work from the femoral vein to create a portocaval shunt that passed through the caudate lobe. This procedure was a technical success and improved the patient's ascites.

Adjunctive 3D US for achieving portal vein access during transjugular intrahepatic portosystemic shunt procedures

PURPOSE

To evaluate the usefulness of information provided by three-dimensional ultrasound (3D US) and to determine whether 3D US decreased the number of passes required to obtain portal vein (PV) access during creation of transjugular intrahepatic portosystemic shunts (TIPS).

MATERIALS AND METHODS

Intermittent 3D US volume acquisitions were obtained during creation of TIPS in 20 patients. Useful information provided by 3D US was tabulated. The number of passes required to achieve PV access was recorded and results were compared retrospectively to 25 patients who underwent TIPS without 3D US.

RESULTS

3D US documented that the operator's opinion of which hepatic vein had been selected was incorrect in nine patients (45%), detected unfavorable PV anatomy that required modification of equipment or technique in seven patients (35%), permitted estimation of the trajectory required to access the targeted PV in all patients (100%), assisted in selecting the optimal point along the hepatic vein for origination of the needle pass in 11 patients (55%), allowed avoidance of a large hepatocellular carcinoma in one patient (5%), and confirmed that access into the main PV was intrahepatic in four patients (20%). The mean number of needle passes decreased from 10.4 in the historic control group to 4.6 in the 3D US group (P = .0001).

CONCLUSION

3D US provided imaging information that detected technical errors and altered anatomy, and provided positional and directional information to significantly improve needle pass efficiency.

Adjunctive 3D US for achieving portal vein access during transjugular intrahepatic portosystemic shunt procedures

PURPOSE

To evaluate the usefulness of information provided by three-dimensional ultrasound (3D US) and to determine whether 3D US decreased the number of passes required to obtain portal vein (PV) access during creation of transjugular intrahepatic portosystemic shunts (TIPS).

MATERIALS AND METHODS

Intermittent 3D US volume acquisitions were obtained during creation of TIPS in 20 patients. Useful information provided by 3D US was tabulated. The number of passes required to achieve PV access was recorded and results were compared retrospectively to 25 patients who underwent TIPS without 3D US.

RESULTS

3D US documented that the operator's opinion of which hepatic vein had been selected was incorrect in nine patients (45%), detected unfavorable PV anatomy that required modification of equipment or technique in seven patients (35%), permitted estimation of the trajectory required to access the targeted PV in all patients (100%), assisted in selecting the optimal point along the hepatic vein for origination of the needle pass in 11 patients (55%), allowed avoidance of a large hepatocellular carcinoma in one patient (5%), and confirmed that access into the main PV was intrahepatic in four patients (20%). The mean number of needle passes decreased from 10.4 in the historic control group to 4.6 in the 3D US group (P = .0001).

CONCLUSION

3D US provided imaging information that detected technical errors and altered anatomy, and provided positional and directional information to significantly improve needle pass efficiency.

Primary placement of Palmaz long medium stents in transjugular intrahepatic portosystemic shunts

PURPOSE

To describe our results with primary placement of the long-medium Palmaz stent for transjugular intrahepatic portosystemic shunts (TIPS).

MATERIALS AND METHODS

Between December 1997 and December 1998 primary placement of long-medium Palmaz stents was performed for TIPS procedures in 17 patients. Patency was determined with ultrasound, angiography, or pathologic examination in the event of transplant.

RESULTS

Primary patency was achieved in 13 of 17 patients (76.5%) (follow up, 1-399 days; mean, 99 days). Secondary patency was achieved in 17 of 17 patients (100%) (follow-up, 1-399 days; mean, 110 days). Among the four patients who required revision, the mean time to revision from initial shunt creation was 81 days (range, 13-125 days). Two of these four patients had symptoms of worsening ascites as well as abnormal ultrasound findings prior to their revision; the other two patients were asymptomatic and had abnormal ultrasound findings only. Revisions were performed for intimal hyperplasia within the stent in three of the patients and acute thrombus within the stent in the remaining patient. Kaplan-Meier survival analysis for primary patency yielded mean survival time of 265 days (standard error, 52 days).

CONCLUSION

The long-medium Palmaz stent is a viable stent for creation of TIPS shunts.

TIPS placement in swine, guided by electromagnetic real-time needle tip localization displayed on previously acquired 3-D CT

PURPOSE

To determine the feasibility of guiding a transjugular intrahepatic portosystemic shunt (TIPS) procedure with an electromagnetic real-time needle tip position sensor coupled to previously acquired 3-dimensional (3-D) computed tomography (CT) images.

METHODS

An electromagnetic position sensor was placed at the tip of a Colapinto needle. The real-time position and orientation of the needle tip was then displayed on previously acquired 3-D CT images which were registered with the five swine. Portal vein puncture was then attempted in all animals.

RESULTS

The computer calculated accuracy of the position sensor was on average 3 mm. Four of five portal vein punctures were successful. In the successes, only one or two attempts were necessary and success was achieved in minutes.

CONCLUSION

A real-time position sensor attached to the tip of a Colapinto needle and coupled to previously acquired 3-D CT images may potentially aid in entering the portal vein during the TIPS procedure.

An iterative algorithm for X-ray CT fluoroscopy

X-ray computed tomography fluoroscopy (CTF) enables image guidance of interventions, synchronization of scanning with contrast bolus arrival, and motion analysis. However, filtered backprojection (FB), the current method for CTF image reconstruction, is subject to motion and metal artifacts from implants, needles, or other surgical instruments. Reduced target lesion conspicuity may result from increased image noise associated with reduced tube current. In this report, we adapt the row-action expectation-maximization (EM) algorithm for CTF. Because time-dependent variation in images is localized during CTF, the row-action EM-like algorithm allows rapid convergence. More importantly, this iterative CTF algorithm has fewer metal artifacts and better low-contrast performance than FB.