Para-Axial Central Venous Stent Placement in Patients with Malignant Central Venous Obstruction with a Venous Port 

Summary

Endovascular central venous stent (CVS) placement has been shown to improve symptoms and outcomes related to central venous obstruction. In patients with malignant central venous obstruction, preservation of previously placed indwelling port catheters is an important consideration during CVS placement. Previously, catheters were removed during CVS placement and replaced within the stent lumen to achieve an intra-stent configuration (i-CVS). This prospective cohort study explores the option of para-axial stent placement (p-CVS) which would obviate the need for removal and replacement of the port catheter. A total of 61 patients with malignant central venous obstruction were included in the study, of which 38 underwent p-CVS and 23 underwent i-CVS. Patients who had previously placed implanted port catheters underwent p-CVS placement. i-CVS placement was performed in all patients who had stents placed prior to port catheter placement. The authors defined successful stent and catheter placement as deployment of the central venous stent without port dysfunction or residual central venous stenosis on completion venography. Follow up chest radiography was used to evaluate for catheter fracture or stent migration. At 6 month follow up, none of the patients suffered from catheter dysfunction/fracture or stent migration. Follow up CT imaging revealed in-stent stenosis in 6/24 of the p-CVS patients and 6/18 of the i-CVS patients, a statistically insignificant difference (p = 0.33).



Figure. (a, b) Transverse CT image and plain chest film show the i-CVS placement state. The catheter (arrow) of the implanted venous port is located in the lumen of the stent. (c, d) Transverse CT image and plain chest film show the p-CVS placement. The catheter (arrow) of the implanted venous port is located between the stent and the vessel wall.

Commentary

The logistical challenges associated with placement of central venous stents in patients with previously placed port catheters have not been previously adequately addressed. Removal and re-implantation of central venous ports or repositioning of the catheter tip using a snare to achieve an intra-stent configuration exposes patients to increased complication risks and additional procedural costs. The authors propose an alternate solution of leaving the port catheter external to the lumen of the stent and were able to show no complications of stent migration or catheter dysfunction as a result of this configuration. The authors do not specifically comment on whether any dual-lumen catheters were used during the study but they do note that a limitation of the study was that small diameter ports were used during the study. Conceivably, use of larger diameter catheters such as dialysis catheters or even dual lumen ports during p-CVS placement could contribute to an increased rate of catheter dysfunction or stent migration. This question needs to be addressed in follow up studies to help determine whether this could be a viable option in patients with ESRD. Longer term follow up is also needed to assess for potential increased complications that could occur with p-CVS placement. Additionally, since only 1 of the para-axial port catheters had to be removed during the study, it is not currently known whether removal of these catheters is associated with increased rates of intra-procedural catheter fracture or stent migration. Nonetheless, this study provides substantial evidence that para-axial port placement in patients with central venous obstruction is a viable option.

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Kim, Su Ho, et al. “Para-Axial Central Venous Stent Placement in Patients with Malignant Central Venous Obstruction with a Venous Port.” Journal of Vascular and Interventional Radiology, vol. 29, no. 11, Nov. 2018, pp. 1567–1570.

Post Author:
Shuaib Mohammad, MD
Department of Radiology
Wake Forest Baptist Medical Center
@WakeForest_IR

Catheter-Directed Thrombolysis for Portal Vein Thrombosis in Children: A Case Series

Summary

Pediatric portal vein thrombosis (PVT) in children has a high morbidity related to portal hypertension (PH). The current study retrospectively described the experience using catheter-directed thrombolysis (CDT) in the treatment of PVT within 10 consecutive children (mean age 11.9 years) undergoing 13 interventions. PVT confirmed via ultrasound or computed tomography was treated by first obtaining percutaneous transhepatic and/or transjugular intrahepatic portal access followed by placement of a transjugular intrahepatic portosystemic shunt (TIPS) in patients with PH. CDT consisted of intraprocedural tissue plasminogen activator (tPA) administration followed by mechanical thrombectomy, and if indicated, overnight thrombolysis.

Complete thrombolysis and partial thrombolysis was achieved in 7 (53.8%) and 3 (23.1%) cases, respectively. Two major complications occurred including hemoperitoneum requiring blood transfusion and right hemothorax requiring chest tube placement. Six patients (66%) did not have recurrent PVT on mean follow-up of 30.4 months. Regarding the remaining 3 patients; one developed cavernous transformation of the portal vein, one was found to have an occlusion of the left portal vein, and one developed recurrent thrombosis of the portal vein. CDT for PVT can be safely performed in children with similar recanalization rates to those recorded in literature for thrombolysis in PVT in adults.

Figure
Incremental response to CDT in a 15-year-old girl with PVT and superior mesenteric vein involvement. (a) Initial portal venogram from a PTH approach demonstrates extensive thrombus throughout the superior mesenteric vein with extension into the main, right, and left portal veins. (b) Follow-up portal venogram obtained after 36 hours of tPA infusion demonstrating partial lysis of PVT with decreased thrombus burden in the main portal vein but with continued extensive thrombus in the superior mesenteric vein. (c) Final portal venogram obtained after CDT in conjunction with TIPS placement demonstrating complete lysis of previously seen PVT.

Commentary

This case series represents the largest cohort of pediatric patients undergoing CDT for the treatment of PVT and attempts to establish the efficacy and safety of the procedure in this population.

Interestingly, both major complications occurred as a result of percutaneous transhepatic access. It would appear that utilization of the transjugular approach not only reduces the complication profile of the procedure, but also facilitates simultaneous TIPS placement in patients with PH. As access and familiarity with intravascular ultrasound expands, transjugular access for CDT within the portal system should become more efficient and safer.

All patient were discharged on twice-daily enoxaparin for a minimum of 3 months, with 2 patients receiving additional aspirin 81 mg daily. Given this younger population, consideration regarding long-term anticoagulation and the associated risks must be balanced with probability of developing recurrent PVT.

Currently, CDT in PVT in children appears to be a technically safe procedure with promising recanalization rates. Prospective studies with systematic procedural and follow-up imaging protocols are still required to fully understand the safety profile and long-term efficacy of this procedure.

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Koo KSH, Lamar DL, Shaw DWW, Monroe EJ, Shivaram GM. Catheter-Directed Thrombolysis for Portal Vein Thrombosis in Children: A Case Series. Journal of Vascular and Interventional Radiology. 2018 Nov 1;29(11):1578–83.

Post Author:
Jacob Bundy, MD, MPH
PGY-1
Department of Surgery
University of Michigan Health System
@JBundyRad

Albumin-Bilirubin Score: An accurate Predictor of Hepatic Decompensation in High-Risk Patients Undergoing Transarterial Chemoembolization for Hepatocellular Carcinoma

Summary

Patient selection is a critical component within the decision paradigm in patients with hepatocellular carcinoma. Most interventional radiologists use total bilirubin values and Child-Turcotte-Pugh (CP) scores to aid in decision making. In fact, CP scores are one of four factors that comprise the Barcelona Clinic Liver Cancer (BCLC) classification, along with tumor extension, physical status, and cancer-related symptoms. However, the CP score was originally created to predict mortality following surgery in the cirrhotic population. Under BCLC recommendations, any CP class C patient is recommended for best supportive care, relegating a significant number of patients without a treatment option.

The albumin-bilirubin (ALBI) grade was created in 2015 as a purely objective assessment of underlying liver function. The goal of this study from the Stanford group was to identify predictors of acute-on-chronic liver failure (ACLF) following chemoembolization (TACE) and evaluating the use of ALBI grade as a predictor of ACLF in the high risk patients. The study evaluated patients with a CP score greater than or equal to 8 who underwent TACE. Patients were treated with both conventional TACE and drug-eluting-bead TACE. ALBI grades were designated as grade 1 if ≤ -2.60, grade 2 if > -2.60 but ≤ -1.39, and grade 3 if > -1.39. ACLF was reported at 30 days and 90 days following TACE using the chronic liver failure-sequential organ failure assessment algorithm.

ACLF occurred within 30 days in 8% of cases, with an additional 5% between 30 and 90 days. Significant predictors of ACLF or worsening ascites or encephalopathy at 90 days included bilirubin, albumin, and ALBI grade. ALBI score was the only remaining statistically significant variable following multivariate regression analysis. The authors concluded that TACe can be performed safely in patients with moderate to severe liver dysfunction and that ALBI score can help determine risk stratification.



Figure 2. Prediction curve from logistic regression model for ACLF at 90 days using ALBI scores showing the risk of ACLF is negligible for ALBI scores < -1.5, increases minimally when the ALBI score reaches -1.39 (ABLI grade 3), and increases rapidly as the ALBI score nears 0.

ALBI Score = (log10 bilirubin x 0.66) + (albumin x -0.085)
Bilirubin is in µmol/L and albumin in g/L.

Commentary

In the past three years, ALBI score has drawn a fair amount of attention within the interventional oncology world as a purely objective scale for predicting survival within cirrhotics with hepatocellular carcinoma. Patients with moderate and severe liver dysfunction and hepatocellular carcinoma have proven to be a challenging patient population. Following the BCLC algorithm, any patient with CP class C liver dysfunction is deemed terminal with recommendation for best supportive care. This study demonstrates the role of the ALBI score in aiding interventional radiologists in selecting which CP C patients are safe to TACE, with risk of ACLF increasing only when the ALBI score > -1. With using ALBI to determine which high risk patients have unacceptable morbidity and mortality risks following TACE, a significant population of CP C patients could now be offered treatment confidently. The impact would include improving overall survival with potential to down-stage patients to become transplant candidates or keep them transplant eligible. This paper adds to the existing literature supporting the use of ALBI score in not only survival prediction, but also risk stratification for ACLF and thus tumor board decision making and patient counseling.

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Mohmammed M, Khalaf M, Liang T, et al. Albumin-Bilirubin Score: An Accurate Predictor of Hepatic Decompensation in High-Risk Patients Undergoing Transarterial Chemoembolization for Hepatocellular Carcinoma. J Vasc Interv Radiol. 2018; 29: 1527-1534.

Post Author:
David M Mauro, MD
Assistant Professor
Department of Radiology
Vascular and Interventional Radiology
University of North Carolina
@DavidMauroMD