Intrahepatic flow diversion prior to segmental Yttrium-90 radioembolization for challenging tumor vasculature

Background

Hepatic tumors with complex vascular supply or poor relative perfusion are prone to decreased rates of objective response. This is compounded in the setting of Yttrium-90 (Y90) transarterial radioembolization (TARE), which is minimally embolic and flow-dependent, relying on high threshold dose for complete response.

Objective

We describe our experience with intrahepatic flow diversion (FD) prior to TARE of hepatocellular carcinoma (HCC) with challenging vascular supply.

Materials and methods

Between April 2014 and January 2020, 886 cases of coinciding MAA or TARE and bland embolization or temporary occlusion were identified. Intraprocedural embolizations performed for more routine purposes were excluded. FD was performed by bland embolization or temporary occlusion of vessels supplying non-malignant parenchyma in cases where flow was not preferential to target tumor. Lesion characteristics, vascular supply, treatment approach, angiography, and adverse events (AEs) were reviewed. Radiographic response was assessed using mRECIST criteria.

Results

22 cases of FD of focal HCC were identified. Embolics included calibrated microspheres (n ​= ​11), microcoils (n ​= ​4), gelfoam (n ​= ​3), temporary balloon occlusion (n ​= ​2) and temporary deployment of a microvascular plug (n ​= ​1). Post-treatment SPECT-CT dosimetry coverage was concordant with target lesions in all cases. Mean follow-up was 16.7 months (1.4-45 ​mos). Tumor-specific response per mRECIST was 41% complete response, 50% objective response, and 59% disease control rate. No major adverse events or grade 3/4 hepatotoxicity were reported.

Conclusion

Our findings suggest that FD prior to TARE is safe and potentially effective in treating HCC with complex vascular supply or poor tumor perfusion.

Nylon Fibered Versus Non-Fibered Embolization Coils: Comparison in a Swine Model

PURPOSE

To determine whether nylon fibers improve the performance of platinum embolization coils in porcine arteries.

MATERIALS AND METHODS

Platinum 0.035" embolization coils, both with and without nylon fibers, were used to embolize a total of 24 hindlimb arteries in 6 swine: 12 with fibered coils and 12 with non-fibered coils. Apart from fibers, the coils were identical. Immediate and late results were studied, including number of coils needed to achieve vessel occlusion and durability of occlusion at 1 and 3 months. Arteriographic as well as histopathologic analysis were performed.

RESULTS

A mean of 3.2 (range, 2-4) non-fibered coils was required to achieve occlusion, whereas a mean of 1.3 (range, 1-2) fibered coils achieved occlusion in similarly sized arteries (2.3-3.2-mm diameter, P < .001). The mean percent cross-sectional area occupied by thrombus was greater in arteries with fibered coils than with non-fibered coils at 1 month (63% ± 6% and 48% ± 15%, respectively, P = .03) but not at 3 months (61% ± 6% and 49% ± 15%, respectively, P = .06). Some recanalization was observed at follow-up and did not differ between groups at 1 month (P = .07) or 3 months (P = .22).

CONCLUSIONS

Nylon fibers allow significantly fewer embolization coils to achieve acute occlusion of arteries compared to bare metal coils. Both fibered and non-fibered coils showed recanalization at follow-up.

Red Flags, Pitfalls, and Cautions in Y90 Radiotherapy

Radioembolization with yttrium-90 (Y90) microspheres is increasingly used to palliate patients with liver-dominant malignancy. With appropriate patient selection, this outpatient treatment is efficacious with limited toxicity profile. This article reviews common scenarios that can present in daily practice including evaluation of liver functions, evaluation of previous therapies, integrating Y90 into ongoing systemic therapy, determining performance status, and considering retreatment for patients who have already undergone Y90 who have hepatic dominant progression. Finally, we address the importance of evaluating tumors in potential watershed zones to maximize treatment response by using c-arm computed tomography. Many of these potential variables can overlap in an individual patient. By considering these factors individually, the consulting Interventional Radiologist can present a thorough treatment plan with a full description of expected outcomes and toxicities to clinic patients.

Gastrodoudenal Embolization: Indications, Technical Pearls, and Outcomes

The gastroduodenal artery (GDA) is frequently embolized in cases of upper GI bleed that has failed endoscopic therapy. Additionally, it may be done for GDA pseudoaneurysms or as an adjunctive procedure prior to Yttrim-90 (Y90) treatment of hepatic tumors. This clinical review will summarize anatomy and embryology of the GDA, indications, outcomes and complications of GDA embolization.

Coil embolization of reversed-curve hepatointestinal collaterals in radioembolization: potential solutions for a challenging task

Depending on the planned catheter position for selective internal radioembolization, coil embolization of hepatic artery branches can be necessary to enable a selective and safe procedure. The anatomy of the hepatic arterial bed has been demonstrated to have a substantial number of anatomic variations, which turns coil embolization into a challenge if the feeder shows a reversed, "hairpin-like" turn immediately after its origin. Hepatointestinal collateral vessels originating from the periphery of the right hepatic artery often present with such a reversed course and can preclude patients from uncomplicated radioembolization if catheterization fails. The purpose of this report is to describe 2 potential solutions for successful coil embolization of reversed-curve hepatointestinal collateral vessels using either a regular 4 French RIM catheter or a novel steerable tip-deflecting microcatheter.

Radioembolization: Is Prophylactic Embolization of Hepaticoenteric Arteries Necessary? A Systematic Review

PURPOSE

To study the effectiveness of prophylactic embolization of hepaticoenteric arteries to prevent gastrointestinal complications during radioembolization.

METHODS

A PubMed, Embase and Cochrane literature search was performed. We included studies assessing both a group of patients with and without embolization.

RESULTS

Our search revealed 1401 articles of which title and abstract were screened. Finally, eight studies were included investigating 1237 patients. Of these patients, 456 received embolization of one or more arteries. No difference was seen in the incidence of gastrointestinal complications in patients with prophylactic embolization of the gastroduodenal artery (GDA), right gastric artery (RGA), cystic artery (CA) or hepatic falciform artery (HFA) compared to patients without embolization. Few complications were reported when microspheres were injected distal to the origin of these arteries or when reversed flow of the GDA was present. A high risk of confounding by indication was present because of the non-randomized nature of the included studies.

CONCLUSION

It is advisable to restrict embolization to those hepaticoenteric arteries that originate distally or close to the injection site of microspheres. There is no conclusive evidence that embolization of hepaticoenteric arteries influences the risk of complications.

Safety of Radioembolization with (90)Yttrium Resin Microspheres Depending on Coiling or No-Coiling of Aberrant/High-Risk Vessels

PURPOSE

To evaluate the safety of radioembolization (RE) with (90)Yttrium ((90)Y) resin microspheres depending on coiling or no-coiling of aberrant/high-risk vessels.

MATERIALS AND METHODS

Early and late toxicity after 566 RE procedures were analyzed retrospectively in accordance with the National Cancer Institute's Common Terminology Criteria for Adverse Events (CTCAE v3.0). For optimal safety, aberrant vessels were either coil embolized (n = 240/566, coiling group) or a more peripheral position of the catheter tip was chosen to treat right or left liver lobes (n = 326/566, no-coiling group).

RESULTS

Clinically relevant late toxicities (≥ Grade 3) were observed in 1% of our overall cohort. The no-coiling group had significantly less "any" (P = 0.0001) or "clinically relevant" (P = 0.0003) early toxicity. There was no significant difference (P > 0.05) in delayed toxicity in the coiling versus the no-coiling group. No RE-induced liver disease was noted after all 566 procedures.

CONCLUSION

RE with (90)Y resin microspheres is a safe and effective treatment option. Performing RE without coil embolization of aberrant vessels prior to treatment could be an alternative for experienced centers.

Selective internal radiation therapy of hepatic tumours: is coiling of the gastroduodenal artery always beneficial?

AIM

To assess the effect of gastroduodenal artery (GDA) occlusion prior to selective internal radiation therapy (SIRT) with regards to arterial hepato-intestinal collateralization (HIC).

MATERIALS AND METHODS

Six hundred and six patients were scheduled for SIRT between 2006 and 2012 at University Hospital Essen, Germany. Digital subtraction angiography (DSA) followed by administration of 99m-technetium labelled human serum albumin microspheres ((99m)Tc-HSAM) and single-photon emission computed tomography combined with computed tomography (SPECT/CT) was initially performed. Depending on vascular anatomy and hepatic tumour load, GDA coil embolization was considered. In subsequent (99m)Tc-HSAM rescans or therapeutic DSA, HIC and its consequences for SIRT were analysed.

RESULTS

The GDA was occluded in 86 of 606 patients (14%). Twenty-two of these 86 patients did not undergo SIRT due to the patients' clinical status or SIRT contraindications. In 28 of the remaining 64 patients, newly apparent or reopened HIC were seen either at the site of the proximal GDA (n = 21) or in the periphery of the hepatic arteries (n = 7). In 25 of these 28 patients, the HIC could be occluded or the catheter position could be changed achieving a safe (90)Y application. However, due to the newly visible HIC in three of 28 patients, SIRT was regarded as unsafe and was abandoned.

CONCLUSION

Coil embolization of the GDA may induce arterial hepato-intestinal collaterals. Although most of these collaterals do not impede (90)Y administration, SIRT may become unfeasible in specific occasions. Hence, segmental or lobar SIRT instead of a whole-liver approach with coiling of the GDA is recommended.

Gastroduodenal artery recanalization after transcatheter fibered coil embolization for prevention of hepaticoenteric flow: incidence and predisposing technical factors in 142 patients

BACKGROUND

Prophylactic occlusion of extrahepatic vessels prior to radioembolization or chemotherapy infusion is an effective method to prevent gastrointestinal complications. Unfortunately, vascular recanalization can occur.

PURPOSE

To retrospectively determine the rate and technical factors associated with gastroduodenal artery (GDA) recanalization after transcatheter occlusion with fibered coils.

MATERIAL AND METHODS

Patients with hepatic malignancy who underwent fibered coil occlusion of the GDA origin for radioembolization or hepatic arterial chemotherapy infusion with at least one subsequent hepatic angiogram between March 2006 and January 2011 were included. One hundred and forty-two patients (men, 71; women, 71) met study criteria. Hepatic arteriograms were reviewed to determine the frequency of arterial recanalization. Additional parameters included: patients' demographics, GDA diameter, length of coil pack, distance between GDA origin and most cephalad coil, persistent flow at the conclusion of the initial GDA occlusion procedure, platelet count, and international normalized ratio (INR). Chi-square test and pooled t-test were used to compare the two groups. Prospective multivariate analysis was performed with a logistic regression model.

RESULTS

Twenty-nine of 142 patients (20.4%) experienced GDA recanalization. The distance between the GDA origin and most cephalad coil was significantly greater in the recanalization group than in the non-recanalization group (9.6 mm vs. 12.6 mm, P = 0.01). A prospective multivariate analysis established that the further the coil was from the origin the more likely the GDA was to recanalize. The two groups did not differ on the basis of any other factors examined.

CONCLUSION

GDA origin recanalization after fibered coil occlusion is common. The distance between the GDA origin and most cephalad coil appears to be a predisposing factor for recanalization. Familiarity with this phenomenon is beneficial to reduce the likelihood of gastrointestinal tract complications during hepatic locoregional therapy.

Superiority of proximal embolization of the gastroduodenal artery with the Amplatzer vascular plug 4 before yttrium-90 radioembolization: a retrospective comparison with coils in 134 patients

PURPOSE

To evaluate the effectiveness of proximal embolization of the gastroduodenal artery (GDA) using the Amplatzer Vascular Plug 4 (AVP 4) compared with pushable coils to avoid hepaticoenteric collaterals of the GDA stump, which may serve as pathways for nontarget embolization.

MATERIALS AND METHODS

One hundred thirty-four patients scheduled for 90-yttrium radioembolization (Y-90 RE) using either plugs (n = 67) or standard coils (n = 67) for GDA occlusion were retrospectively analyzed. Parameters recorded were length of the perfused GDA stump, distance device to the GDA origin, perfused proximal side branches after embolization, and durability of vessel occlusion at Y-90 RE.

RESULTS

Length of the residually perfused GDA stump was 3.89 ± 2.86 mm for the AVP 4, which was significantly shorter compared with 5.78 ± 3.85 mm for coils (p = 0.005). Distance of the plug to the GDA origin was 1.41 ± 2.60 mm, which was also significantly shorter than 4.73 ± 3.44 mm for coils (p < 0.001). This resulted in significantly fewer patients with residually perfused side branches in the AVP 4 group (n = 2; 3.0%) compared with the coil group (n = 18; 26.9%; p < 0.001). At Y-90 RE, no GDA reperfusion was found after plug embolization compared with 2 cases after coil embolization (3.0%; p = 0.156). Only one patient had a radiation-induced duodenal ulcer after coil embolization, whereas no Y-90-related toxicity was identified after plug embolization.

CONCLUSION

Use of the AVP 4 for embolization of the GDA allowed an optimal proximal and more effective target vessel occlusion compared with coil embolization, which can avoid complications caused by extrahepatic gastrointestinal deposition of Y-90 microspheres by way of residually perfused proximal side branches.