Clinical evaluation of in silico planning and real-time simulation of hepatic radiofrequency ablation (ClinicIMPPACT Trial).

OBJECTIVES: To evaluate the accuracy and clinical integrability of a comprehensive simulation tool to plan and predict radiofrequency ablation (RFA) zones in liver tumors. METHODS: Forty-five patients with 51 malignant hepatic lesions of different origins were included in a prospective multicenter trial. Prior to CT-guided RFA, all patients underwent multiphase CT which included acquisitions for the assessment of liver perfusion. These data were used to generate a 3D model of the liver. The intra-procedural position of the RFA probe was determined by CT and semi-automatically registered to the 3D model. Size and shape of the simulated ablation zones were compared with those of the thermal ablation zones segmented in contrast-enhanced CT images 1 month after RFA; procedure time was compared with a historical control group. RESULTS: Simulated and segmented ablation zone volumes showed a significant correlation (ρ = 0.59, p < 0.0001) and no significant bias (Wilcoxon's Z = 0.68, p = 0.25). Representative measures of ablation zone comparison were as follows: average surface deviation (absolute average error, AAE) with 3.4 ± 1.7 mm, Dice similarity coefficient 0.62 ± 0.14, sensitivity 0.70 ± 0.21, and positive predictive value 0.66 ± 0. There was a moderate positive correlation between AAE and duration of the ablation (∆t; r = 0.37, p = 0.008). After adjustments for inter-individual differences in ∆t, liver perfusion, and prior transarterial chemoembolization procedures, ∆t was an independent predictor of AAE (ß = 0.03 mm/min, p = 0.01). Compared with a historical control group, the simulation added 3.5 ± 1.9 min to the procedure. CONCLUSION: The validated simulation tool showed acceptable speed and accuracy in predicting the size and shape of hepatic RFA ablation zones. Further randomized controlled trials are needed to evaluate to what extent this tool might improve patient outcomes. KEY POINTS: • More reliable, patient-specific intra-procedural estimation of the induced RFA ablation zones in the liver may lead to better planning of the safety margins around tumors. • Dedicated real-time simulation software to predict RFA-induced ablation zones in patients with liver malignancies has shown acceptable agreement with the follow-up results in a first prospective multicenter trial suggesting a randomized controlled clinical trial to evaluate potential outcome benefit for patients.

GPU-based RFA simulation for minimally invasive cancer treatment of liver tumours.

PURPOSE: Radiofrequency ablation (RFA) is one of the most popular and well-standardized minimally invasive cancer treatments (MICT) for liver tumours, employed where surgical resection has been contraindicated. Less-experienced interventional radiologists (IRs) require an appropriate planning tool for the treatment to help avoid incomplete treatment and so reduce the tumour recurrence risk. Although a few tools are available to predict the ablation lesion geometry, the process is computationally expensive. Also, in our implementation, a few patient-specific parameters are used to improve the accuracy of the lesion prediction. METHODS: Advanced heterogeneous computing using personal computers, incorporating the graphics processing unit (GPU) and the central processing unit (CPU), is proposed to predict the ablation lesion geometry. The most recent GPU technology is used to accelerate the finite element approximation of Penne's bioheat equation and a three state cell model. Patient-specific input parameters are used in the bioheat model to improve accuracy of the predicted lesion. RESULTS: A fast GPU-based RFA solver is developed to predict the lesion by doing most of the computational tasks in the GPU, while reserving the CPU for concurrent tasks such as lesion extraction based on the heat deposition at each finite element node. The solver takes less than 3 min for a treatment duration of 26 min. When the model receives patient-specific input parameters, the deviation between real and predicted lesion is below 3 mm. CONCLUSION: A multi-centre retrospective study indicates that the fast RFA solver is capable of providing the IR with the predicted lesion in the short time period before the intervention begins when the patient has been clinically prepared for the treatment.

Incidental finding of sclerosing angiomatoid nodular transformation of the spleen.

BACKGROUND: The prevalence of tumors in the spleen is rare; most tumors are benign and of vascular origin. In 2004 a vascular lesion was first described, the sclerosing angiomatoid nodular transformation (SANT), which is a benign lesion with good circumscription and multinodular angiomatoid appearance. We report a case of this rare tumor in the spleen which was incidentally found in a patient with a tumorous lesion in the pancreatic tail. CASE REPORT: A 69-year-old patient was referred to our hospital with a tumor in the pancreatic tail which was suspicious for cancer. Radiologic work-up revealed furthermore a 4 cm in diameter large lesion central in the spleen suspicious for metastasis of the pancreatic tumor. The patient underwent surgery and a distal pancreatectomy with splenectomy was performed. Histologic specimen obtained a sclerosing angiomatoid nodular transformation in the spleen. The operative and postoperative course was uneventful. CONCLUSIONS: SANT of the spleen are very rare tumors and should be considered as an important differential diagnosis to other vascular lesions.

Vessel segmentation for ablation treatment planning and simulation.

In this paper, a novel segmentation method for liver vasculature is presented, intended for numerical simulation of radio frequency ablation (RFA). The developed method is a semiautomatic hybrid based on multi-scale vessel enhancement combined with ridge-oriented region growing and skeleton-based postprocessing. In addition, an interactive tool for segmentation refinement was developed. Four instances of three-phase contrast enhanced computed tomography (CT) images of porcine liver were used in the evaluation. The results showed improved accuracy over common approaches and illustrated the method's suitability for simulation purposes.

Sclerosing mesenteritis, a rare cause of a retroperitoneal tumor.

Sclerosing mesenteritis is a chronic and extremely rare inflammatory process that predominantly affects the small bowel mesentery. However, the peripancreatic region, the omentum and the retroperitoneum can also be involved. The etiology and pathogenesis of the disease are as yet unknown, but autoimmune disorders, previous abdominal surgery, trauma, ischemia and drugs could play a role. The clinical picture is nonspecific and varies from asymptomatic to diffuse abdominal complaints. Radiologic work-up and histologic evaluation of a biopsy specimen usually do not reveal typical findings and therefore establishment of the correct diagnosis is challenging. Owing to the rarity of the disease, there is no consensus on optimal pharmaceutical treatment and most patients are treated empirically. Surgical therapy is limited to biopsies for histologic confirmation of the tumor and management of complications. We report a case of a 51-year-old man with a large retroperitoneal mass. Magnetic resonance angiography showed a 9.7 x 7.7 x 5.9 cm tumor above the aortic bifurcation with encasement of the aorta and the vena cava. CT-guided biopsy was inconclusive but surgical biopsy provided a histologic diagnosis of sclerosing mesenteritis. The operative and postoperative course was uneventful and therapy with prednisolone and azathioprine was started. At 6 months' follow-up, the patient was in good condition and asymptomatic. Sclerosing mesenteritis, though a rare entity, should be included in the differential diagnosis when a patient presents with a mesenterial or retroperitoneal tumor.

Computer oriented image acquisition of the liver: Toward a better numerical model for radiofrequency ablation.

Simulating physiological interventions for planning purposes requires an accurate virtual liver model as computation input. To best meet the demands the data acquisition has to be oriented on image processing purposes. We provide a CT imaging protocol which makes it possible to extract much more vessels with the same segmentation algorithms than when using them on data sets from the clinical routine. Medical evaluation of physiological models demand a statistical evaluation in a pre-clinical study, that means in a first step reproducible results for a large number of subjects. So data acquisition should be as automatic as possible without neglecting modeling demands. Image quality should be reproducible to guarantee an ongoing high quality of image processing results. We evaluate the protocol by comparison of segmentation results with results achieved on standard data sets from clinical routine using the same segmentation methods. Results show that typically up to ten times more vessels can be extracted and the surface accuracy is improved.

Graz Endocrine Causes of Hypertension (GECOH) study: a diagnostic accuracy study of aldosterone to active renin ratio in screening for primary aldosteronism.

BACKGROUND: Primary aldosteronism (PA) affects approximately 5 to 10% of all patients with arterial hypertension and is associated with an excess rate of cardiovascular complications that can be significantly reduced by a targeted treatment. There exists a general consensus that the aldosterone to renin ratio should be used as a screening tool but valid data about the accuracy of the aldosterone to renin ratio in screening for PA are sparse. In the Graz endocrine causes of hypertension (GECOH) study we aim to prospectively evaluate diagnostic procedures for PA. METHODS AND DESIGN: In this single center, diagnostic accuracy study we will enrol 400 patients that are routinely referred to our tertiary care center for screening for endocrine hypertension. We will determine the aldosterone to active renin ratio (AARR) as a screening test. In addition, all study participants will have a second determination of the AARR and will undergo a saline infusion test (SIT) as a confirmatory test. PA will be diagnosed in patients with at least one AARR of >or= 5.7 ng/dL/ng/L (including an aldosterone concentration of >or= 9 ng/dL) who have an aldosterone level of >or= 10 ng/dL after the saline infusion test. As a primary outcome we will calculate the receiver operating characteristic curve of the AARR in diagnosing PA. Secondary outcomes include the test characteristics of the saline infusion test involving a comparison with 24 hours urine aldosterone levels and the accuracy of the aldosterone to renin activity ratio in diagnosing PA. In addition we will evaluate whether the use of beta-blockers significantly alters the accuracy of the AARR and we will validate our laboratory methods for aldosterone and renin. CONCLUSION: Screening for PA with subsequent targeted treatment is of great potential benefit for hypertensive patients. In the GECOH study we will evaluate a standardised procedure for screening and diagnosing of this disease.

Towards validation for physiological models in intervention planning.

Computer supported treatment planning systems aim at predicting treatment results. Recently attacked challenges base not only on anatomical findings, but include physiological processes. This way, interventions which are highly depending on patient physiology become predictable and can be supported in computer based planning. Though the necessity to validate computations used for treatment planning is unquestioned available models lack validation. This contribution discusses challenges for designing a validation study for the example intervention of radiofrequency ablation (RFA) in the liver.

Endovascular treatment of mycotic aortic pseudoaneurysms with stent-grafts.

Mycotic aortic aneurysms remain a therapeutic challenge, especially in patients who are not suitable for open surgery. Endovascular treatment with stent-grafts in this indication is still disputed. Between January 2002 and January 2006, six patients with mycotic aneurysms of the thoracoabdominal or abdominal aorta were admitted to our department. All patients were male, aged 57-83 years (mean, 74.6 years). The mycotic aneurysms were diagnosed on the basis of clinical signs of infection, on CT, and, in four cases, on a positive blood culture. In all patients the mycotic aortic aneurysms were treated endovascularly by stent-graft implantation. Technical and clinical success was achieved in all patients. There was no in-hospital or 30-day mortality. In the follow-up period (range, 2-47 months) four patients died of cancer, cardiac failure, or unknown cause (one case). Two patients are still alive with nearly complete regression of the aneurysms. We conclude that treatment of mycotic aortic aneurysms with stent-grafts may be an alternative in selected patients.

Fatal hemobilia resulting from an iatrogenic arteriobiliary fistula as a rare complication of transjugular liver biopsy.

Transjugular liver biopsy is an important tool for diagnosing and/or staging of advanced liver disease. This procedure is considered safe even in the presence of severe coagulopathy, although rare fatal complications have been described. We herein report the first case of fatal hemobilia after transjugular liver biopsy. A patient with alcoholic liver cirrhosis developed hematemesis 1 day after transjugular liver biopsy. Upper gastrointestinal endoscopy revealed bleeding from the papilla of Vater. Despite early intervention by angiography and embolization of an arteriobiliary fistula, the patient deteriorated and ultimately died due to multiorgan failure.

Partial splenic embolization in children with hereditary spherocytosis.

OBJECTIVES: Although total splenectomy is able to reduce clinical symptoms in patients with hereditary spherocytosis (HS), splenectomized patients are at risk to develop overwhelming bacterial infections and, to a lesser extent, thromboembolic complications. In contrast, partial splenectomy or partial splenic embolization (PSE) may also decrease the rate of hemolytic complications while maintaining residual splenic function. The aim of this study was to investigate the benefit of PSE in children with moderate to severe HS. PATIENTS AND METHODS: We performed PSE via retrograde transfemoral access in eight children (four female, four male) with moderate to severe HS at a median age of 8 yr. HS-related complications before PSE included gallstones in six and aplastic crises in four children. One patient was transfusion-dependent. RESULTS: No acute side effects were seen during or after PSE. Median hemoglobin increased significantly from levels between 7.5 g/dL and 11.65 g/dL before PSE to levels between 8.4 g/dL and 13.35 g/dL after PSE (P = 0.012). Median splenic sizes before PSE ranged from 9.7 cm/m2 to 19.0 cm/m2 and significantly decreased to values between 4.4 cm/m2 and 15.65 cm/m2 during follow-up (P = 0.012). CONCLUSIONS: PSE appears to be a safe, effective and feasible treatment option for the management of children with moderate to severe HS.

Hepatic encephalopathy following transjugular intrahepatic portosystemic shunt (TIPS): management with L-ornithine-L-aspartate and stent reduction.

Hepatic encephalopathy (HE) is a common problem after insertion of a trans-jugular intrahepatic portosystemic shunt (TIPS), which may be difficult to manage. We present a case of severe post-TIPS HE unresponsive to high doses of L-ornithine-L-aspartate (LOLA) despite reduction of venous ammonia levels in a dose-dependent fashion. Ultimately, high-grade HE was successfully treated by a reduction stent and the patient subsequently underwent successful liver transplantation.

Routine use of three-dimensional contrast-enhanced moving-table MR angiography in patients with peripheral arterial occlusive disease: comparison with selective digital subtraction angiography.

PURPOSE: To compare the diagnostic accuracy of contrast-enhanced (CE) three-dimensional (3D) moving-table magnetic resonance (MR) angiography with that of selective digital subtraction angiography (DSA) for routine clinical investigation in patients with peripheral arterial occlusive disease. METHODS: Thirty-eight patients underwent CE 3D moving-table MR angiography of the pelvic and peripheral arteries. A commercially available large-field-of-view adapter and a dedicated peripheral vascular phased-array coil were used. MR angiograms were evaluated for grade of arterial stenosis, diagnostic quality, and presence of artifacts. MR imaging results for each patient were compared with those of selective DSA. RESULTS: Two hundred and twenty-six arterial segments in 38 patients were evaluated by both selective DSA and MR angiography. No complications related to MR angiography were observed. There was agreement in stenosis classification in 204 (90.3%) segments; MR angiography overgraded 16 (7%) segments and undergraded 6 (2.7%) segments. Compared with selective DSA, MR angiography provided high sensitivity and specificity and excellent interobserver agreement for detection of severe stenosis (97% and 95%, kappa = 0.9 +/- 0.03) and moderate stenosis (96.5% and 94.3%, kappa = 0.9 +/- 0.03). CONCLUSION: Compared with selective DSA, moving-table MR angiography proved to be an accurate, noninvasive method for evaluation of peripheral arterial occlusive disease and may thus serve as an alternative to DSA in clinical routine.

Percutaneous nephrostomy and antegrade ureteral stenting: technique-indications-complications.

In this review the technique, indication for and complications of percutaneous nephrostomy (PCN) and antegrade ureter stent insertion are described. In the majority of the cases PCN is performed to relieve urinary obstruction, which can be of benign or malignant nature. Another indication for PCN is for treatment of urinary fistulas. PCN can be performed under ultrasound and/or fluoroscopic guidance, with a success rate of more than 90%. The complication rate is approximately 10% for major and minor complications together and 4-5% for major complications only. Percutaneous antegrade double-J stent insertion usually is performed if retrograde ureter stenting has not been successful. However, especially in malignant obstructions, the success rate for antegrade stenting is higher than for retrograde transvesical double-J stent insertion. In the case of severe infection and bleeding after PCN JJ-stent insertion may be contraindicated so long as there is no sufficient concomitant drainage via a PCN . Lower urinary tract dysfunction should be excluded before stent placement. The complication rate is 2-4%. Consequent stent surveillance with regular stent exchange is mandatory.

Three-dimensional gadolinium-enhanced magnetic resonance angiography used as a "one-stop shop'' imaging procedure for venous thromboembolism: a pilot study.

Pulmonary embolism and deep venous thrombosis are individual manifestations of a single entity, venous thromboembolic disease. This study aimed to assess the feasibility of 3-dimensional gadolinium-enhanced magnetic resonance angiography used as an "one-stop shop'' imaging procedure visualizing both the pulmonary arteries and the deep lower venous system within a single investigation. The inclusion criterion was a proven or excluded venous thromboembolism. Diagnosis was based on an imaging work-up for pulmonary embolism including either perfusion lung scan or contrast-enhanced spiral computed tomography, or both, and an imaging work-up for deep venous thrombosis including either venous color-coded duplex sonography or ascending phlebography, or both. A gadolinium-enhanced "one-stop shop'' magnetic resonance angiography was performed within 24 hours of completed diagnostic imaging work-up for pulmonary embolism and deep venous thrombosis in 20 patients. Results of pulmonary magnetic resonance angiography were concordant with perfusion lung scan and/or computed tomography in 90% of patients. Magnetic resonance angiography results of the deep lower venous system were concordant with venous duplex sonography and/or phlebography in 75% of patients and seemed to be more precise in 25% of patients. The "one-stop shop'' imaging procedure using gadolinium-enhanced magnetic resonance angiography was feasible and proved to offer a reliable and rapid diagnostic approach in thromboembolic disease, sparing patients' exposure to ionizing radiation and iodinated contrast media.

Crimping and repositioning of a maldeployed balloon-expandable arterial stent using a gooseneck snare.

PURPOSE: To describe a technique for repositioning a fully deployed iliac stent from the infrarenal aorta into the common iliac artery (CIA). CASE REPORT: A 58-year-old man was undergoing treatment for a significant right CIA stenosis when a 7x24-mm Palmaz Genesis medium stent was mistakenly deployed in the infrarenal aorta. With the stent still over the guidewire, an 8x60-mm balloon catheter was placed coaxially in the stent. Via a left groin access, a 6-F vascular sheath was introduced retrograde, and a 2.5-cm Amplatz gooseneck snare was advanced into the infrarenal abdominal aorta and pulled back over the stent. The snare was tightly closed to crimp the stent onto the collapsed balloon; this maneuver was repeated several times until the stent was contracted along its entire length. The balloon/stent assembly was carefully pulled back into the right CIA, and the stent was deployed across the target lesion, although there was overlap of the left CIA. Color duplex sonography at 1 year showed no signs of significant iliac arterial stenoses on either side. The patient reported no claudication. CONCLUSIONS: Using a gooseneck snare, fully deployed balloon-expandable iliac stents can be recrimped on a balloon.

Frequency and significance of lumbar and inferior mesenteric artery perfusion after endovascular repair of abdominal aortic aneurysms.

PURPOSE: To evaluate the frequency and influence of perfused side branches (lumbar arteries [LA] and inferior mesenteric artery trunks) on development of type II endoleaks (EL-II) and on volume changes of abdominal aortic aneurysms (AAA) after endovascular repair. METHODS: Of 114 patients undergoing EVR of AAA, 89 patients (83 men; mean age 72+/-7.5 years, range 51-88) with >6 months' follow-up and no type I endoleaks were retrospectively analyzed to determine any relationships between retrograde perfusion, endoleaks, and sac volume. Data were derived from computed tomographic angiographic (CTA) scans taken before and after intervention, at discharge, and at 1, 3, 6, and semi-annually thereafter in follow-up. Two groups were identified and compared based on their status at 6 months post EVR: without perfused side branches (group 1) and with perfused collaterals (group 2); group 2 was further divided according to the absence (2a) or presence (2b) of endoleak. RESULTS: Median follow-up was 24 months (range 6-36). Based on a total of 582 CTAs analyzed, 17 (19%) patients developed type II endoleaks (EL-II) during follow-up. There was a significant difference in the number of perfused LAs prior to EVR between groups 1 (n=44) and the 45 patients with postprocedural patent collateral arteries in group 2 (p<0.05); there was no significant difference between groups 2a and 2b (p=0.88) relative to the number of pre-existing patent collaterals. The number of pLAs preoperatively and the rate of type II endoleak were significantly correlated (p<0.05). No type II endoleak was seen in patients without perfused side branches (p=0.01). No significant differences in mean volumes were found between groups 1 and 2a (no EL-II), but significant differences between groups 1 and 2b were seen in later follow-up. CONCLUSIONS: A larger number of patent LAs before EVR was associated with a significantly higher rate of type II endoleak. Patent collateral vessels were common after aneurysm repair, but the frequency decreased during follow-up. Persistent side branch perfusion was associated with increased type II endoleak after endovascular AAA repair. Significant differences in volume changes in later follow-up were seen between patients with or without type II endoleak.

The outback catheter: a new device for true lumen re-entry after dissection during recanalization of arterial occlusions.

PURPOSE: To report the initial experience with a new catheter system (The Outback catheter) designed to allow fluoroscopically controlled re-entry of the true arterial lumen after subintimal guidewire passage during recanalization procedures of arterial occlusions. METHODS: The catheter was used in 10 patients with intermittent claudication caused by chronic segmental occlusions of the superficial femoral or popliteal arteries. In all patients, conventional guidewire recanalization had failed. RESULTS: In 8 patients, successful true lumen re-entry was achieved with the Outback catheter. Percutaneous transluminal angioplasty was successfully performed in these patients without complications. Two technical failures occurred in heavily calcified arteries. CONCLUSION: The Outback catheter was safe and effective when used in complicated recanalization procedures in the superficial femoral and popliteal artery and the tibial trunk.

Multislice spiral CT angiography in peripheral arterial occlusive disease: a valuable tool in detecting significant arterial lumen narrowing?

The aim of this study was to evaluate the potential of multislice CT angiography (CTA) in detecting hemodynamically significant (> or =70%) lesions of lower extremity inflow and runoff arteries. Fifty patients (42 men, 8 women; mean age 68 years) with peripheral arterial occlusive disease underwent multislice spiral CTA and digital subtraction angiography (DSA) from the infrarenal aorta to the supramalleolar region. CT parameters were 4x2.5-mm collimation, 15-mm table increment/rotation (pitch 6), and 1.25-mm reconstruction increment. Semitransparent volume rendering technique (STVR) images with semitransparent display of the arterial lumen (opacity: 50%) and vascular calcifications (opacity: 20%), as well as maximum intensity projection (MIP), and MIP together with axial CT studies were independently reviewed for hemodynamically significant lesions (> or =70% cross-sectional area reduction). DSA was the standard of reference. In 46 patients, 260 lesions were found (95 stenoses, 165 occlusions). For detecting > or =70% lesions in all vessel regions, sensitivity and specificity were 84% and 78% (STVR), 89% and 74% (MIP), and 92% and 83% (MIP+axial CT), respectively, with a significantly lower sensitivity of STVR ( p<0.05) and a significantly lower specificity of MIP studies ( p<0.01). Sensitivity and specificity were, respectively, 81% and 93% (STVR), 88% and 75% (MIP). and 92% and 95% (MIP+axial CT) at aortoiliac arteries, 92% and 73% (STVR), 95% and 70% (MIP) and 98% and 70% (MIP+axial CT) at femoropopliteal arteries, as well as 82% and 64% (STVR), 86% and 74% (MIP), and 90% and 74% (MIP+axial CT) at infrapopliteal arteries. Specificity of MIP-CTA was significantly lower in the aortoiliac region ( p<0.01), whereas STVR revealed significantly lower specificity at infrapopliteal arteries ( p<0.05). In the infrapopliteal region, the particular CTA imaging modalities led to misinterpretation regarding stenoses and occlusions in 39-45 cases, whereas only 0-6 significant aortoiliac and femoropopliteal lesions were misinterpreted. Multislice CTA is helpful in detecting hemodynamically significant lesions in peripheral arterial occlusive disease. Since axial CT studies yielded the most correct results, they should always be reviewed additionally. In the infrapopliteal region, exact lesion assessment remains problematic due to small vessel diameters.

Transjugular intrahepatic portosystemic shunt creation with the Viatorr expanded polytetrafluoroethylene-covered stent-graft.

PURPOSE: To evaluate the midterm clinical results and patency of transjugular portosystemic shunts (TIPS) created with a commercially available expanded polytetrafluoroethylene (ePTFE)-covered stent-graft based on angiographic and ultrasonographic (US) criteria in a series of 71 patients. MATERIALS AND METHODS: Seventy-one patients (61 men, 10 women; mean age, 58.6 years, range, 25-78 years) were included in this series, which was performed in two centers. Indications for TIPS creation were refractory ascites (n = 44) and recurrent esophageal bleeding (n = 27). Ten patients had Child-Pugh class A liver cirrhosis, 43 had class B disease, and 18 had class C disease. Underlying liver diseases were alcoholic cirrhosis (n = 58), cirrhosis resulting from hepatitis (n = 9), cryptogenic cirrhosis (n = 3), and Budd-Chiari syndrome (n = 1). TIPS were created with commercially available ePTFE-covered stent-grafts in all patients. The diameters of the stent-grafts were 10 mm in 58 patients and 8 mm in the remaining 13 patients. Follow-up included clinical examination and color-coded US after 5 days, 1, 3, and 6 months, and every 6 months thereafter. Shunt angiograms were obtained every 6 months. Median follow-up was 16.3 months (range, 3.8-26.6 months). RESULTS: TIPS creation was successful in all patients without complications, and effective portal decompression was observed with a reduction of the mean portal gradient from 19 mm Hg to 6 mm Hg before and after TIPS creation. Four shunt occlusions were observed after 5 days, 2 months, 3 months, and 6 months. Shunt stenosis was observed in three patients at the hepatic vein, which was not fully covered by the stent-graft, after 6 months (n = 2) and 12 months, and at the portal side after 1 month in a patient who initially had portal vein thrombosis. The repeat intervention rate was 11.3%. The primary patency rates were 87.4% (95% CI, 77.7%-97.1%) after 6 months and 80.8% (95% CI, 68.2%-93.4%) after 12 months. The rate of de novo or deteriorated hepatic encephalopathy was 31%. The recurrent bleeding rate was 3.7% (one of 27), and ascites improved or resolved in 64% of patients after 1 month. CONCLUSION: TIPS patency can be significantly increased if the ePTFE-covered stent-graft is used for shunt creation. The increased shunt patency contributes to low repeat intervention and recurrent bleeding rates. The rate of hepatic encephalopathy is within the range of previously reported rates.