Irreversible Electroporation for Hepatic Tumors: Protocol Standardization Using the Modified Delphi Technique

PurposeA consensus study of panelists was performed to provide a uniform protocol regarding (contra) indications, procedural parameters, perioperative care, and follow-up of irreversible electroporation (IRE) for the treatment of hepatic malignancies.Materials and MethodsInterventional radiologists who had 2 or more publications on IRE, reporting at least 1 patient cohort in the field of hepatobiliary IRE, were recruited. The 8 panelists were asked to anonymously complete 3 iterative rounds of IRE-focused questionnaires to collect data according to a modified Delphi technique. Consensus was defined as having reached 80% or greater agreement.ResultsPanel members’ response rates were 88%, 75%, and 88% in rounds 1, 2, and 3, respectively; consensus was reached on 124 of 136 items (91%). Percutaneous or intraoperative hepatic IRE should be considered for unresectable primary and secondary malignancies that are truly unsuitable for thermal ablation because of proximity to critical structures. Absolute contraindications are ventricular arrhythmias, cardiac stimulation devices, and congestive heart failure of New York Heart Association class 3 or higher. A metal stent outside the ablation zone should not be considered a contraindication. For the only commercially available IRE device, the recommended settings are an inter-electrode distance of 10–20 mm and an exposure length of 20 mm. After 10 test pulses, 90 treatment pulses of 1500 V/cm should be delivered continuously, with a pulse length of 70–90 μs. The first post-procedural follow-up should take place 1 month after IRE and thereafter every 3 months, using cross-sectional imaging plus tumor marker assessment.ConclusionsThis article provides recommendations, created by a modified Delphi consensus study, regarding patient selection, workup, procedure, and follow-up of IRE treatment for hepatic malignancies.     

Intra-arterial Injection of Lidocaine as a Cell Sensitizer during Irreversible Electroporation

PurposeTo investigate whether intra-arterial injection of lidocaine enhances irreversible electroporation (IRE) in a liver model.Materials and MethodsConventional IRE (C-IRE) and lidocaine-enhanced IRE (L-IRE) were performed in 8 pig livers. Protocol 1 (tip exposure and electrode distance of 2.0 cm each) and protocol 2 (increased tip exposure and electrode distance 2.5 cm each) were used. Animals were sacrificed 3 hours after IRE. Study goals included electrical tissue properties (eg, current, conductivity) during IRE, geometry of IRE zones analyzed using computed tomography and magnetic resonance imaging (eg, volume and sphericity index), degree of acute liver damage, and irreversible cell death analyzed using microscopy (hematoxylin and eosin staining and terminal deoxynucleotidyl transferase deoxyuridine 5-triphosphate nick end labeling). Statistical comparisons were performed using the paired t test and Wilcoxon test.ResultsAll treatments were performed without adverse events. Electrical tissue properties were not significantly different between C-IRE and L-IRE. For protocol 1, the diameter of the largest sphere within the IRE zone was significantly larger for L-IRE than for C-IRE (25.0 ± 4.7 mm vs 18.4 ± 3.1 mm [P = .013]). For protocol 2, the volume of IRE zone was significantly larger for L-IRE compared with C-IRE (46.0 ± 5.4 cm³ vs 22.6 ± 6.4 cm³ [P = .018]), as well as the diameter of the largest sphere within the IRE zone (27.1 ± 2.2 mm vs 19.8 ± 2.3 mm [P = .020]). For protocol 1, a significantly higher degree of irreversible cell death was noted for L-IRE than for C-IRE (1.8 ± 1.0 vs 0.8 ± 1.0 [P = .046]).ConclusionsIntra-arterial injection of lidocaine can enhance IRE in terms of larger IRE zones and an increase of irreversible cell death.     

High-Frequency Irreversible Electroporation for Treatment of Primary Liver Cancer: A Proof-of-Principle Study in Canine Hepatocellular Carcinoma

PurposeTo determine the safety and feasibility of percutaneous high-frequency irreversible electroporation (HFIRE) for primary liver cancer and evaluate the HFIRE-induced local immune response.Materials and MethodsHFIRE therapy was delivered percutaneously in 3 canine patients with resectable hepatocellular carcinoma (HCC) in the absence of intraoperative paralytic agents or cardiac synchronization. Pre- and post-HFIRE biopsy samples were processed with histopathology and immunohistochemistry for CD3, CD4, CD8, and CD79a. Blood was collected on days 0, 2, and 4 for complete blood count and chemistry. Numeric models were developed to determine the treatment-specific lethal thresholds for malignant canine liver tissue and healthy porcine liver tissue.ResultsHFIRE resulted in predictable ablation volumes as assessed by posttreatment CT. No detectable cardiac interference and minimal muscle contraction occurred during HFIRE. No clinically significant adverse events occurred secondary to HFIRE. Microscopically, a well-defined ablation zone surrounded by a reactive zone was evident in the majority of samples. This zone was composed primarily of maturing collagen interspersed with CD3⁺/CD4⁻/CD8⁻ lymphocytes in a proinflammatory microenvironment. The average ablation volumes for the canine HCC patients and the healthy porcine tissue were 3.89 cm³ ± 0.74 and 1.56 cm³ ± 0.16, respectively (P = .03), and the respective average lethal thresholds were 710 V/cm ± 28.2 and 957 V/cm ± 24.4 V/cm (P = .0004).ConclusionsHFIRE can safely and effectively be delivered percutaneously, results in a predictable ablation volume, and is associated with lymphocytic tumor infiltration. This is the first step toward the use of HFIRE for treatment of unresectable liver tumors.     

Therapeutic Effect of Irreversible Electroporation in Combination with Poly-ICLC Adjuvant in Preclinical Models of Hepatocellular Carcinoma

PurposeTo evaluate the therapeutic efficacy of irreversible electroporation (IRE) combined with the intratumoral injection of the immunogenic adjuvant poly-ICLC (polyinosinic-polycytidylic acid and poly-L-lysine, a dsRNA analog mimicking viral RNA) inmediately before IRE.Materials and MethodsMice and rabbits bearing hepatocellular carcinoma tumors (Hepa.129 and VX2 tumor models, respectively) were treated with IRE (2 pulses of 2500V), with poly-ICLC, or with IRE + poly-ICLC combination therapy. Tumor growth in mice was monitored using a digital caliper and by computed tomography in rabbits.ResultsIntratumoral administration of poly-ICLC immediately before IRE elicited shrinkage of Hepa.129 cell-derived tumors in 70% of mice, compared to 30% and 26% by poly-ICLC or IRE alone, respectively (P = .0004). This combined therapy induced the shrinkage of VX-2-based hepatocellular carcinoma tumors in 40% of rabbits, whereas no response was achieved by either individual treatment (P = .045). The combined therapy activated a systemic antitumor response able to inhibit the growth of other untreated tumors.ConclusionsIRE treatment, immediately preceded by the intratumoral administration of an immunogenic adjuvant such as poly-ICLC, might enhance the antitumor effect of the IRE procedure. This combination might facilitate the induction of a long-term systemic response to prevent tumor relapses and the appearance of metastases.     

Experimental High-Frequency Irreversible Electroporation Using a Single-Needle Delivery Approach for Nonthermal Pancreatic Ablation In Vivo

PurposeTo investigate the feasibility of single-needle high-frequency irreversible electroporation (SN-HFIRE) to create reproducible tissue ablations in an in vivo pancreatic swine model.Materials and MethodsSN-HFIRE was performed in swine pancreas in vivo in the absence of intraoperative paralytics or cardiac synchronization using 3 different voltage waveforms (1-5-1, 2-5-2, and 5-5-5 [on-off-on times (μs)], n = 6/setting) with a total energized time of 100 μs per burst. At necropsy, ablation size/shape was determined. Immunohistochemistry was performed to quantify apoptosis using an anticleaved caspase-3 antibody. A numerical model was developed to determine lethal thresholds for each waveform in pancreas.ResultsMean tissue ablation time was 5.0 ± 0.2 minutes, and no cardiac abnormalities or muscle twitch was detected. Mean ablation area significantly increased with increasing pulse width (41.0 ± 5.1 mm² [range 32–66 mm²] vs 44 ± 2.1 mm² [range 38–56 mm²] vs 85.0 ± 7.0 mm² [range 63–155 mm²]; 1-5-1, 2-5-2, 5-5-5, respectively; p < 0.0002 5-5-5 vs 1-5-1 and 2-5-2). The majority of the ablation zone did not stain positive for cleaved caspase-3 (6.1 ± 2.8% [range 1.8–9.1%], 8.8 ± 1.3% [range 5.5–14.0%], and 11.0 ± 1.4% [range 7.1–14.2%] cleaved caspase-3 positive 1-5-1, 2-5-2, 5-5-5, respectively), with significantly more positive staining at the 5-5-5 pulse setting compared with 1-5-1 (p < 0.03). Numerical modeling determined a lethal threshold of 1114 ± 123 V/cm (1-5-1 waveform), 1039 ± 103 V/cm (2-5-2 waveform), and 693 ± 81 V/cm (5-5-5 waveform).ConclusionsSN-HFIRE induces rapid, predictable ablations in pancreatic tissue in vivo without the need for intraoperative paralytics or cardiac synchronization.     

Outcomes of Irreversible Electroporation for Perihilar Cholangiocarcinoma: A Prospective Pilot Study

PurposeTo investigate the safety and efficacy of percutaneous or open irreversible electroporation (IRE) in a prospective cohort of patients with locally advanced, unresectable perihilar cholangiocarcinoma (PHC).Materials and MethodsIn a multicenter Phase I/II study, patients with unresectable PHC due to extensive vascular involvement or N2 lymph node metastases or local recurrence after resection for PHC were included and treated by open or percutaneous IRE combined with palliative chemotherapy (current standard of care). The primary outcome was the number of major adverse events occurring within 90 d after IRE (grade ≥3), and the upper limit was predefined at 60%. Secondary outcomes included technical success rate, hospital stay, and overall survival (OS).ResultsTwelve patients (mean age, 63 y ± 12) were treated with IRE. The major adverse event rate was 50% (6 of 12 patients), and no 90-d mortality was observed. All procedures were technically successful, with no intraprocedural adverse events requiring additional interventions. The median OS from diagnosis was 21 mos (95% confidence interval, 15–27 mos), with a 1-y survival rate of 75% after IRE.ConclusionsPercutaneous IRE in selected patients with locally advanced PHC seems feasible, with a major adverse event rate of 50%, which was below the predefined upper safety limit in this prospective study. Future comparative research exploring the efficacy of IRE is warranted.     

High-Frequency Irreversible Electroporation Using 5,000-V Waveforms to Create Reproducible 2- and 4-cm Ablation Zones—A Laboratory Investigation Using Mechanically Perfused Liver

PurposeTo investigate if high-frequency irreversible electroporation (H-FIRE) treatments can be delivered at higher voltages and with greater energy delivery rates than currently implemented in clinical irreversible electroporation protocols.Materials and MethodsTreatments using 3,000 V and 5,000 V were administered to mechanically perfused ex vivo porcine liver via a single applicator and grounding pad (A+GP) as well as a 4-applicator array (4AA). Integrated energized times (IET) 0.01–0.08 seconds and energy delivery rates 25–300 μs/s were investigated. Organs were preserved at 4°C for 10–15 hours before sectioning and gross analysis using a metabolic stain to identify the size and shape of ablation zones.ResultsA+GP ablations measured between 1.6 cm and 2.2 cm, which did not increase when IET was increased from 0.02 seconds to 0.08 seconds (P > .055; range, 1.9–2.1 cm). Changes in tissue color and texture consistent with thermal damage were observed for treatments with energy delivery rates 50–300 μs/s, but not for treatments delivered at 25 μs/s. Use of the 4AA with a 3-cm applicator spacing resulted in ablations measuring 4.4–4.9 cm with energy delivery times of 7–80 minutes.ConclusionsH-FIRE treatments can rapidly and reproducibly create 2-cm ablations using an A+GP configuration. Treatments without thermal injury were produced at the expense of extended treatment times. More rapid treatments resulted in ablations with varying degrees of thermal injury within the H-FIRE ablation zone. Production of 4-cm ablations is possible using a 4AA.     

Hepatic Hilar Nerve Block for Adjunctive Analgesia during Percutaneous Thermal Ablation of Hepatic Tumors: A Retrospective Analysis

PurposeTo determine whether hepatic hilar nerve block techniques reduce analgesic and sedation requirements during percutaneous image-guided thermal ablation of hepatic tumors.Materials and MethodsA single-center retrospective cohort analysis was performed of 177 patients (median age, 67 years; range, 33–86 years) who underwent percutaneous image-guided thermal ablation of liver tumors. All patients were treated utilizing local anesthetic and moderate sedation between November 2018 and November 2021 at a tertiary level hospital, with or without the administration of a hepatic hilar nerve block. Univariable and multivariable linear regression analyses were performed to determine the relationship between the administration of the hilar nerve block and fentanyl and midazolam dosages.ResultsA total of 114 (64%) patients received a hilar nerve block in addition to procedural sedation, and 63 (36%) patients received procedural sedation alone. There were no significant differences in the baseline demographic and tumor characteristics between the cohorts. The procedure duration was longer in the hilar block cohort than in the unblocked cohort (median, 95 vs 82 minutes; P = .0012). The technical success rate (98% in both the cohorts, P = .93) and adverse event rate (11% vs 3%, P = .14) were not significantly different between the cohorts. After adjusting for patient and tumor characteristics, ablation modality, and procedure and ablation durations, hilar nerve blocks were associated with lower fentanyl (?18.4%, P = .0045) and midazolam (?22.7%, P = .0007) dosages.ConclusionsHepatic hilar nerve blocks significantly decrease the fentanyl and midazolam requirements during thermal ablation of hepatic tumors, without a significant change in the technical success or adverse event rates.     

Predictors of Survival after Yttrium-90 Radioembolization of Chemotherapy-Refractory Hepatic Metastases from Breast Cancer

PurposeTo determine predictors of survival after transarterial radioembolization of hepatic metastases from breast cancer.Materials and MethodsTwenty-four patients with chemotherapy-refractory hepatic metastases from breast cancer who underwent radioembolization from 2013 to 2018 were evaluated based on various demographic and clinical factors before and after treatment. Overall survival (OS) was estimated by Kaplan–Meier method. Log-rank analysis was performed to determine predictors of prolonged OS from the time of first radioembolization and first hepatic metastasis diagnosis.ResultsMedian OS times were 35.4 and 48.6 months from first radioembolization and time of hepatic metastasis diagnosis, respectively. Radioembolization within 6 months of hepatic metastasis diagnosis was a positive predictor of survival from first radioembolization, with median OS of 38.9 months vs 22.1 months for others (P = .033). Estrogen receptor (ER)–positive status predicted prolonged survival (38.6 months for ER⁺ vs 5.4 months for ER⁻; P = .005). The presence of abdominal pain predicted poor median OS: 12.8 months vs 38.6 months for others (P < .001). The presence of ascites was also a negative predictor of OS (1.7 months vs 35.4 months for others; P = .037), as was treatment-related grade ≥ 2 toxicity at 3 months (5.4 months vs 38.6 months for others; P = .017).ConclusionsIn patients with metastatic breast cancer, radioembolization within 6 months of hepatic metastasis diagnosis and ER⁺ status appear to be positive predictors of prolonged survival. Conversely, baseline abdominal pain, baseline ascites, and treatment-related grade ≥ 2 toxicity at 3 months after treatment appear to be negative predictors of OS.     

Value of CT-Guided Percutaneous Irreversible Electroporation Added to FOLFIRINOX Chemotherapy in Locally Advanced Pancreatic Cancer: A Post Hoc Comparison

PurposeTo compare survival after CT-guided percutaneous irreversible electroporation (IRE) and folinic acid, fluorouracil, irinotecan, and oxaliplatin (FOLFIRINOX) chemotherapy versus FOLFIRINOX only in patients with locally advanced pancreatic cancer (LAPC).Materials and MethodsA post hoc comparison was performed of data derived from a prospective IRE-FOLFIRINOX cohort and a retrospective FOLFIRINOX-only cohort. All patients received a minimum of 3 cycles of FOLFIRINOX for LAPC and were considered eligible for CT-guided percutaneous IRE. Endpoints included overall survival (OS), local and distant progression-free survival, and time to progression (TTP) and were compared using stratified Kaplan-Meier analysis. Patients who received > 8 cycles of FOLFIRINOX before IRE and who had tumors > 6 cm in the FOLFIRINOX-only group were excluded.ResultsOf 103 patients with a diagnosis of LAPC, 52 were deemed eligible (n = 30 IRE-FOLFIRINOX and n = 22 FOLFIRINOX-only). Patients in the FOLFIRINOX-only arm had larger tumors (53 mm ± 19 vs 38 mm ± 7, P = .340), had more locoregional lymph node metastases (23% vs 7%, P = .622), and more often received radiotherapy (7 patients vs 2 patients, P = .027); all other baseline characteristics were comparable. Median OS was 17.0 months (range, 5–35 mo; SD = 6) for IRE-FOLFIRINOX versus 12.4 months (range, 3–22 mo; SD = 6) for FOLFIRINOX-only (P = .038). After sensitivity analyses, median OS was 17.2 months (range, 6–27 mo; SD = 6) versus 12.4 months (range, 7–32 mo; SD = 10) (P = .05). Median TTP was longer in the IRE-FOLFIRINOX group: 14.2 months (range, 5–25 mo; SD = 4) versus 5.2 months (range, 2–22; SD = 6) (P = .0001).ConclusionsIn patients with LAPC after FOLFIRINOX chemotherapy, CT-guided percutaneous IRE may improve OS and TTP. This study may facilitate the design of randomized controlled trials to compare survival after IRE-FOLRINOX versus FOLFIRINOX-only.     

Relationship of Antenna Work and Ablation Cavity Volume Following Percutaneous Microwave Ablation of Hepatic Tumors

PurposeTo formulate a statistical model relating ablation time, power, and work with posttreatment cavity volume following percutaneous microwave ablation of hepatic tumors in vivo.Materials and MethodsA retrospective review (October 2015 to October 2018) yielded 122 hepatic tumors treated with microwave ablation. Ablation cavity dimensions were measured at 1-month follow-up examination and calculated using an ellipsoid volume formula. The antenna manufacturer (Neuwave Medical, Madison, Wisconsin) provided the activation time and energy used to calculate the antenna work. Generalized estimating equations with ordinary least-squares regression models were obtained to relate tumor volume with cumulative antenna work. Coefficient of determination (R²) and mean square error were used as statistical measures of model prediction performance.ResultsThere is a logarithmic relationship between postablation cavity volume (cm³) and cumulative work (kJ), represented by the formula: log₁₀ cm³ = ?0.4583 + 0.9887 × cumulative work (log10 kJ) (R² = 0.41, mean square error, 0.102). Ablation volumes were predicted as a function of antenna work, calculated using an antilog transformation. When a single antenna was used, ablation cavity volume was predicted using a generalized estimating equation ordinary least-squares regression model of power and time: log₁₀cm³= ?0.0546 + 0.0485 × total time (min) + 0.0107 × power (W) (R² = 0.30; mean square error, 0.106). Using this model, a nomogram was developed to predict the postablation cavity volume based on total activation time and target power.ConclusionThere is a logarithmic relationship between the ablation work and posttreatment ablation cavity volume, which can be expressed in a nomogram when using a single probe.     

Changes in Modified Raymond–Roy Classification Occlusion Classes and Predictors of Recurrence-Free Survival in Patients with Intracranial Aneurysms after Endovascular Coil Embolization

PurposeTo assess changes in modified Raymond–Roy classification (MRRC) occlusion classes and recurrence rates over time and evaluate recurrence-free survival after coil embolization and its predictors.Materials and MethodsDuring 2007–2016, 201 patients (mean age, 57.1 ± 13.4 years; 75.5% women) with 240 aneurysms treated with coil embolization were enrolled. MRRC Class I (n = 210), Class II (n = 14), Class IIIa (n = 10), and Class IIIb (n =6) closures were assessed. Recurrence was defined as recanalization in MRRC Class I closures or an increase of at least 20% in any of the dimensions of the remnants of the other classes. Recurrence-free survival and its predictors were analyzed using survival analysis.ResultsMost changes in MRRC class occurred in the first year after treatment. MRRC Class I closures had a slightly lower probability of change than that associated with other classes within 1–5 years, whereas Class IIIb closures remained unchanged. Rates of recurrence or regression for all classes were highest within the first year. The median recurrence-free survival times among patients with Class IIIa and Class IIIb closures were 11.56 and 5.55 months, respectively. Significant predictors of recurrence included aneurysm size of 13–24 mm, ruptured or wide-necked aneurysms, and MRRC Class IIIa or IIIb closures.ConclusionsClass changes and recurrence rates for all MRRC classes were highest in the first year. MRRC Class IIIb closures had the highest recurrence rate and the shortest recurrence-free survival. Recurrence risk increased in Classes IIIa and IIIb and with large, ruptured or wide-necked aneurysms.     

The Use of the Transfemoral Transcaval Liver Biopsy Technique for Biopsies of Hepatic Masses

The purpose of this study was to investigate the safety and effectiveness of the transfemoral transcaval (TFTC) liver biopsy technique in patients with hepatic masses with relative contraindications to percutaneous biopsy and/or mass location abutting the inferior vena cava. The medical records of 16 patients (56% men; age range, 21–88 years) who underwent TFTC biopsy of hepatic masses (ranging in diameter from 2.1 to 13.2 cm) from September 2015 to August 2021 were reviewed. Histopathologic diagnoses were made in 15 of 17 (88%) procedures. Two adverse events were noted: worsened preexisting hemobilia requiring embolization in 1 patient, and a decrease in hematocrit level in another patient, requiring only observation. In conclusion, this report showed that the TFTC technique is a relatively safe and effective method for sampling hepatic masses in select cases.     

Radiofrequency Ablation of Liver Tumors in Patients on Antithrombotic Therapy: A Case-Control Analysis of over 10,000 Treatments

PurposeTo evaluate the safety of radiofrequency ablation (RFA) for liver tumors in patients on antithrombotic therapy.Materials and MethodsA total of 10,653 consecutive RFA treatments in 3,485 patients with liver tumors were analyzed. The incidence of complications was analyzed on a treatment basis. The treatments for patients who had received antithrombotic medication up to 1 week prior to RFA comprised the antithrombotic therapy group (n = 806), and the others comprised the control group (n = 9,847). Antithrombotic agents were ceased prior to RFA (aspirin, ticlopidine, clopidogrel, and prasugrel ceased 7 days before RFA; cilostazol, 2 or 3 days before RFA; warfarin, 3 days before RFA; and direct oral anticoagulants, 1 day before RFA) and resumed as soon as possible after RFA. Logistic regression analysis was performed to assess whether the antithrombotic therapy increased the risk of hemorrhagic complications.ResultsHemorrhagic complications were diagnosed after 6 treatments (0.7%) in the antithrombotic group and 48 (0.5%) in the control group, and there was no significant difference between the groups (P = .30). In 3 treatments, hemorrhage was diagnosed on or after 8 days of RFA, all of which were in the antithrombotic group. Thrombotic complications were diagnosed after 2 treatments (0.2%) in the antithrombotic group and after 5 (0.1%) in the control group. In a multivariate analysis, receiving antithrombotic therapy was not an independent risk factor for hemorrhagic complications (adjusted odds ratio, 1.52; 95% confidence interval, 0.60–3.87; P = .38).ConclusionsRFA of liver tumors in patients on antithrombotic therapy is generally safe with appropriate cessation and resumption. Late-onset hemorrhage should be noted in the patients on antithrombotic therapy.     

Temporary Vascular Occlusion with Retrievable Microvascular Plugs to Protect Normal Liver during Yttrium-90 Radioembolization

This case series describes a technique to protect nondiseased liver parenchyma during transarterial radioembolization (TARE) using microvascular plugs to occlude nontarget vessels temporarily and protect normal liver. This technique, defined as temporary vascular occlusion, was performed in 6 patients, with complete vessel occlusion obtained in 5 of the 6 patients and partial occlusion with flow reduction in 1 of the 6 patients. A statistically significant (P = .001) dose decrease of 5.7 ± 3.1 times was measured using postadministration yttrium-90 positron emission tomography/computed tomography in the protected zone compared with that in the treated zone.     

Predictors of Improvement of Sarcopenia after Transjugular Intrahepatic Portosystemic Shunt Creation in Cirrhotic Patients

To investigate the risk factors affecting the improvement of sarcopenia after transjugular intrahepatic portosystemic shunt (TIPS) in cirrhotic patients, this study retrospectively analyzed the data of 111 cirrhotic patients with sarcopenia who underwent TIPS creation. Computed tomography–based measurement of skeletal muscle area was used to calculate skeletal muscle index (SMI) in all patients at baseline and 6 months after TIPS creation. Multivariate logistic regression analysis was used to identify independent risk factors, which showed a significant increase in 6-month post-TIPS SMI compared with that at baseline in both men and women (for both, P < .001). Pre-TIPS SMI (odds ratio [OR], 0.93; 95% CI, 0.87–0.99; P = .031) and change in portal pressure gradient (OR, 1.13; 95% CI, 1.03–1.24; P = .009) were found to be independent risk factors for experiencing substantial improvement in post-TIPS SMI.     

Predictors of Disease Recurrence after Venoplasty and Stent Placement for May–Thurner Syndrome

PurposeTo identify factors independently associated with disease recurrence after venoplasty and stent placement for May–Thurner syndrome (MTS).Materials and MethodsFifty-nine consecutive patients (age, 47 y ± 15; 93% female) were identified who had undergone endovascular stent placement for MTS. Patient charts were reviewed for demographic data, risk factors for venous thrombosis, comorbidities, and venous inflow or outflow at first follow-up (3 wk to 6 mo after treatment). Logistic regression was used to identify independent predictors of symptom recurrence or repeat intervention, and multivariate analysis of variance and receiver operator characteristic curve analysis were used to assess relationships between degrees of in-stent stenosis and other variables in the 73% of patients with available cross-sectional imaging. Median follow up was 20.7 months (interquartile range, 4.7–49.5 mo).ResultsAll procedures were technically successful. Disease recurrence, defined as symptom recurrence following initial postprocedural resolution, was observed in 38% of patients. No preprocedural variable was found to be independently predictive of disease recurrence; however, poor venous inflow or outflow were both strongly associated with recurrent disease, with adjusted odds ratios and 95% confidence intervals of 38.02 (3.76–384.20; P = .002) and 7.00 (1.15–42.71; P = .04), respectively. Higher degrees of in-stent stenosis were also associated with symptom recurrence, with an area under the curve of 0.93 (P = .000002) and 39%–41% stenosis being 78%–83% sensitive and 88%–92% specific for symptom recurrence.ConclusionsThese results suggest that cross-sectional imaging can help differentiate patients in whom closer follow-up may be warranted after venoplasty and stent placement for MTS and also guide counseling regarding prognosis.     

Prognostic Factors for Local Recurrence after Cryoablation of Desmoid Tumors

PurposeTo determine the risk factors for local of adult patients treated for desmoid tumors by cryoablation.Materials and MethodsEighty-four patients treated for nonabdominopelvic desmoid tumors by cryoablation from July 2012 to July 2020 were included in a retrospective study. The population was composed of 64 women (76.19%) and 20 men (23.81%), aged from 16 to 75 years (median, 35 years ± 14.25). Each patient underwent preprocedural gadolinium-enhanced magnetic resonance imaging and was followed up to 36 months with the same technique. Clinical features, such as tumor size and previous treatment, epidemiological features, and the technical parameters of cryoablation, were studied.ResultsLocal relapse was found in 19 (22.62%) of 84 patients. The 12-, 24-, and 36-month progression-free survival rates were 89% (95% confidence interval [CI], 79–94), 74% (95% CI, 60–83), and 68% (95% CI, 53–79), respectively. In univariate analysis, significant prognostic factors associated with local recurrence were non–abdominal wall location (P = .042), debulking strategy (P = .0105), risk of visceral injury (P = .034) or peripheral nerve injury during cryoablation (P = .033), previous radiation therapy (P = .043), and treatment before 2016 (P = .008). In multivariate analysis, abdominal wall tumors displayed the best outcome, whereas the neck and trunk showed a high rate of recurrence (hazard ratio, 7.307 [95% CI, 1.396–38.261]).ConclusionsThe local recurrence of desmoid tumors after cryoablation depends on a number of prognostic factors, in particular, a non–abdominal wall location of the tumor and previous local treatment such as surgery or radiation therapy.     

Simultaneous Stereotactic Radiofrequency Ablation of Multiple (≥ 4) Liver Tumors: Feasibility,Safety, and Efficacy

PurposeTo assess feasibility, safety, and clinical outcome of simultaneous stereotactic radiofrequency (RF) ablation of multiple (≥ 4) primary and metastatic liver tumors.Materials and MethodsThis retrospective observational study included 92 patients (29 women, 62 men), 35 with ≥ 4 hepatocellular carcinomas (HCCs) and 57 with ≥ 4 metastatic liver tumors at initial stereotactic RF ablation between 2005 and 2018. The median size of 178 HCCs and 371 metastases was 2.2 cm (range, 1.0–8.5 cm) and 3.0 cm (range, 0.5–13 cm), respectively. At initial stereotactic RF ablation, 17 (48.6%) patients with HCC and 19 (33.3%) with metastases had 4 liver tumors, 11 (31.4%) and 19 (33.3%) had 5 tumors, and 7 (20%) and 19 (33.3%) had ≥ 6 tumors.ResultsMajor complications occurred in 2 of 35 ablations (5.4%) in patients with HCCs and in 7 of 63 (10%) with metastases. The primary technical efficacy rate (ie, successful initial ablation) was 100% (178/178) in HCCs and 98.8% (363/371) in metastases. Local recurrence was observed in 4 of 178 (2.2%) HCCs and in 17 of 371 (4.6%) metastases. Overall survival (OS) rates at 1, 3, and 5 years from the date of the first stereotactic RF ablation were 88.0%, 54.0%, and 30.4% for patients with HCCs with a median OS of 38.2 months and 86.1%, 53.1%, and 37.3% for patients with metastases with a median OS of 37.4 months.ConclusionsStereotactic RF ablation is a feasible, safe, and efficacious option in simultaneous management of multiple primary and metastatic liver tumors.     

Hepatic Artery Embolization for Postoperative Hemorrhage: Importance of Arterial Collateral Vessels and Portal Venous Impairment

PurposeTo investigate the association between hepatic ischemic complications and hepatic artery (HA) collateral vessels and portal venous (PV) impairment after HA embolization for postoperative hemorrhage.Materials and MethodsFrom October 2003 to November 2019, 42 patients underwent HA embolization for postoperative hemorrhage. HA collateral vessels were classified according to visualization after embolization (grade 1, none; grade 2, 1–4 segmental HA; and grade 3, ≥4 segmental HA). Transhepatic portal vein stent placements were performed in the same session for 5 patients (11.9%) with poor HA collateral vessels (grade 1 or 2) and compromised PV flow (>70% stenosis). Hepatic ischemic complications were analyzed for relevance to HA collateral vessels and PV compromise.ResultsAfter HA embolization, HA flow was found to be preserved (grade 3) through intra- and/or extrahepatic collateral vessels in 23 patients (54.8%), and hepatic complications did not occur regardless of PV flow status (0%). Of the 19 patients (45.2%) with poor HA collateral vessels (grade 1 or 2), segmental hepatic infarction occurred in 2 of 15 patients (13.3%) with preserved PV flow (10 naïve and 5 stented). The remaining 4 patients with poor HA collateral vessels and untreated compromised PV flow experienced multisegmental hepatic infarction (n = 3) or hepatic failure (n = 1) (100%) (P < .005).ConclusionsAfter HA embolization, preserved HA flow (≥4 segmental HA) lowered the risk of hepatic complications regardless of the PV flow. Based on these findings, transhepatic PV stent placement seems to be an effective intervention for the prevention of hepatic complications in cases of poor HA collateral vessels and compromised PV flow.