Endovascular Venous Stenosis and Thrombosis Large Animal Model: Angiographic,Histological, and Biomechanical Characterizations

PurposeTo characterize an ovine endovascular radiofrequency (RF) ablation-based venous stenosis and thrombosis model for studying venous biomechanics and response to intervention.Materials and MethodsUnilateral short-segment (n = 2) or long-segment (n = 6) iliac vein stenoses were created in 8 adult sheep using an endovenous RF ablation technique. Angiographic assessment was performed at baseline, immediately after venous stenosis creation, and after 2-week (n = 6) or 3-month (n = 2) survival. Stenosed iliac veins and the contralateral healthy controls were harvested for histological and biomechanical assessment.ResultsAt follow-up, the short-segment RF ablation group showed stable stenosis without occlusion. The long-segment group showed complete venous occlusion/thrombosis with the formation of collateral veins. Stenosed veins showed significant wall thickening (0.28 vs 0.16 mm, P = .0175) and confluent collagen deposition compared with the healthy controls. Subacute nonadherent thrombi were apparent at 2 weeks, which were replaced by fibrous luminal obliteration with channels of recanalization at 3 months. Stenosed veins demonstrated increased longitudinal stiffness (448.5 ± 5.4 vs 314.6 ± 1.5 kPa, P < .0001) and decreased circumferential stiffness (140.8 ± 2.6 vs 246.0 ± 1.6 kPa, P < .0001) compared with the healthy controls.ConclusionEndovenous RF ablation is a reliable technique for creating venous stenosis and thrombosis in a large animal model with histological and biomechanical attributes similar to those seen in humans. This platform can facilitate understanding of venous biomechanics and testing of venous-specific devices and interventions.     

Technical Feasibility of Suction Thrombectomy Using a Large-Bore Aspiration System in the Portomesenteric Venous System

PurposeTo assess technical feasibility and safety of portal vein thrombectomy with suction thrombectomy using a large-bore thrombectomy device for portomesenteric venous thrombosis (PMVT).Materials and MethodsAfter receiving approval from institutional review board, patients undergoing PMVT treatment using a large-bore aspiration thrombectomy device (Inari FlowTriever or ClotTriever) between July 2019 and June 2021 were identified at 2 medical centers. Charts were reviewed for demographic information, imaging findings, and procedural details. PMVT was categorized using the Yerdel grading system. The thrombectomy procedure was performed via transjugular access through the existing or a new transjugular intrahepatic portosystemic shunt (TIPS) or transsplenic or transhepatic approach. Technical success was defined as successful clot reduction and restoration of portal venous flow at the conclusion of the procedure. Patient outcomes based on clinical presentation, adverse events, and thrombectomy-associated adverse events were recorded.ResultsTwenty patients, with a median age of 58 years (range, 23–72 years), underwent large-bore aspiration thrombectomy, which was technically successful in 19 of 20 (95%) patients. In 9 of 20 (45%) patients, 9 of 20 (45%) patients, and 2 of 20 (10%) patients, the 20-F, 16-F, and 24-F devices were used, respectively. Fourteen patients had a pre-existing TIPS, and 6 patients had a TIPS created. In 5 of 20 (25%) patients, overnight lysis was performed in conjunction with Inari thrombectomy. Thrombus resolution with restoration of flow was achieved in 19 of 20 (95%) cases. There were no thrombectomy-associated adverse events. The mean follow-up time was 70 days (±113) at which time primary patency of the portal venous system was present in 16 of 20 (80%) patients.ConclusionsLarge-bore aspiration portal vein thrombectomy is feasible for PMVT.     

Factors Affecting Recurrent Deep Vein Thrombosis after Pharmacomechanical Thrombolysis and Left Iliac Vein Stent Placement in Patients with Iliac Vein Compression Syndrome

PurposeThis study evaluated the factors affecting contralateral and ipsilateral recurrent deep vein thrombosis (DVT) after iliac vein stent placement in patients with iliac vein compression syndrome (IVCS).Materials and MethodsData from 130 patients (95 female patients) who underwent catheter-directed thrombolysis and stent placement for IVCS with left lower leg thrombosis at a single institution were retrospectively analyzed. Mean patient age was 69.0 ± 14.0 years old. Median follow-up was 14 months (range, 3–164 months). Anticoagulation therapy was prescribed for 6 months, followed by lifelong antiplatelet therapy. Multivariate logistic regression analysis was performed to evaluate the factors affecting the development of contralateral and ipsilateral recurrent DVT.ResultsSeven patients (5.4%) developed contralateral DVT (median, 26 months; range, 2–61 months), and 11 patients (8.5%) developed ipsilateral DVT (median, 1 month; range, 0–53 months). Stent location (odds ratio [OR], 11.564; 95% confidence interval [CI], 1.159–115.417) and in-stent thrombosis during follow-up (OR, 15.142; 95% CI, 1.406–163.119) were predictors of recurrent contralateral DVT. Thrombophilia (OR, 47.560; 95% CI, 2.369–954.711), remaining inferior vena cava filter (OR, 30.552; 95% CI, 3.495–267.122), and in-stent thrombosis during follow-up (OR, 82.057; 95% CI, 2.915–2309.848) were predictors of ipsilateral DVT.ConclusionsContralateral DVT occurs late and is associated with extension of the iliac vein stent to the inferior vena cava and in-stent thrombosis. Ipsilateral DVT occurs relatively early and is associated with thrombophilia, remaining inferior vena cava filter, and in-stent thrombosis.     

Impact of Intrahepatic Venovenous Shunt on Hepatic Venous Pressure Gradient Measurement

PurposeTo quantitatively analyze the impact of intrahepatic venovenous shunt (IHVS) on hepatic venous pressure gradient (HVPG) measurement.Materials and MethodsFrom 2015 to 2019, 222 HVPG measurements performed during transjugular intrahepatic portosystemic shunt creation were eligible for this study. Digital subtraction angiography (DSA) software color-coded each pixel of a two-dimensional DSA series by time-intensity curve to classify IHVS. Different degrees of IHVS were found in 36.5% of patients (81/222). Mild IHVS was found in 10.8% of patients (24/222), moderate IHVS was found in 10.8% of patients (24/222), and severe IVHS was found in 14.9% of patients (33/222).ResultsMean wedged hepatic vein pressure (WHVP) and HVPG were significantly lower in patients with IHVS compared with patients without IHVS (WHVP: 17.78 mm Hg ± 7.00 vs 24.89 mm Hg ± 8.69, P = .001; HVPG: 11.93 mm Hg ± 5.76 vs 18.6 mm Hg ± 6.85, P < .001). Mild IHVS had little effect on WHVP and HVPG. Mean WHVP and HVPG were 11 mm Hg lower in patients with moderate IHVS (WHVP: 20.38 mm Hg ± 8.38 vs 31.5 mm Hg ± 9.39, P = .026; HVPG: 13.88 mm Hg ± 6.33 vs 25.00 mm Hg ± 9.81, P < .001) and 15 mm Hg lower in patients with severe IHVS (WHVP: 13.45 mm Hg ± 5.28 vs 28.64 mm Hg ± 6.38, P = .017; HVPG: 8.27 mm Hg ± 3.85 vs 23.45 mm Hg ± 6.95, P < .001) than mean portal vein pressure and portal vein gradient.ConclusionsFor patients with moderate or severe IHVS, HVPG might greatly underestimate the actual value of portal vein pressure, and the portal vein should be catheterized to measure portal pressure.     

Percutaneous Thrombectomy with the JETi8 Peripheral Thrombectomy System for the Treatment of Deep Vein Thrombosis

PurposeThis study evaluated the safety and efficacy of the JETi8 peripheral thrombectomy system in treating acute deep vein thrombosis (DVT).Materials and MethodsA retrospective study was conducted in 18 consecutive patients (mean age, 41 years old [range, 15-74 years old]; 5 men and 13 women). There were 21 instances of DVTs (9 iliofemoral, 10 axillosubclavian, and 2 portal), which were treated using the JETi8 thrombectomy device between November 2016 and July 2018. Thrombus was laced with recombinant tissue plasminogen activator (r-TPA) (9.3 mg, on average; range, 2–12 mg) in 17 procedures (81%) prior to thrombectomy. Technical success was defined as restoration of antegrade flow using the JETi8 with or without additional treatment of an underlying obstructive lesion. Procedural success was defined as technical success with or without the addition of overnight catheter-directed thrombolysis (CDT)ResultsMean procedure time was 83 minutes (range, 30–160 minutes), and mean thrombus reduction with the JETi8 alone was 92% (range, 60%–100%). Stent placement was required in 6 procedures (29%). Technical success using the JETi8 system alone was 76% (16 of 21 procedures), whereas 5 procedures (24%) required subsequent overnight CDT in the intensive care unit. Procedural success rate was 100% (20 of 20 procedures). Mean aspirated volume was 531 mL (range, 250–1,230 mL). The only adverse event was a subsegmental pulmonary embolism. Seven patients (33%) were discharged the same day. Recurrent thrombosis was observed in 5 patients (24%), of whom 3 were successfully treated with the JETi8 system.ConclusionsThe JETi8 system may be a safe and effective option for thrombectomy of acute DVT.     

Evaluation of a Novel Spun Polytetrafluoroethylene Stent Graft in an Ovine External Iliac Artery Model

PurposeTo evaluate the patency, cellular response, and thrombogenicity of a novel vascular stent graft.Materials and MethodsTest stent grafts, incorporating luminal spun polytetrafluoroethylene and a nonpermeable fluoropolymer layer, and control stent grafts, constructed of permeable expanded polytetrafluoroethylene, were implanted in the external iliac arteries of 14 adult sheep with a median weight of 73.4 kg ranging from 60.6–86.8 kg for 30 (n = 4), 90 (n = 4), and 180 (n = 6) days. Angiographic patency and percent diameter stenosis (%DS) were assessed at termination. Excised stent grafts were fixed and stained for histopathologic analysis, including neointimal coverage (NC) assessment.ResultsTest and control device migration occurred in 1 animal, resulting in test device thrombosis. Both devices were excluded from analysis. Mean %DS in test and control implants was 4.6% and 8.2% (P = .563), 2.0% and 10.9% (P = .363), and 2.1% and 10.3% (P = .009) at 30, 90, and 180 days, respectively. Median NC scores at 30, 90, and 180 days were significantly lower in middle test device sections (P < .05). Proximal and distal test and control sections exhibited similar median NC scores at all time periods (P > .05). When present, test and control devices exhibited no neointimal detachment from the graft surface. Except for the migrated test device, no thrombus was observed. Transgraft cellular migration was absent in test devices but present in control devices with tissue accumulation around the stent struts.ConclusionsTest and control devices demonstrated excellent patency in an ovine model. Compared to the control, test devices exhibited significantly lower %DS values at 180 days and significantly lower mid-device NC scores at 30, 90, and 180 days.     

Maturation for Hemodialysis in the Ellipsys Post-Market Registry

PurposeTo prospectively evaluate the maturation of the endovascular arteriovenous fistula system (EndoAVF) for 2-needle cannulation (2NC).Materials and MethodsFrom October 2018 to June 2019, evaluation of 123 patients resulted in 95 arteriovenous fistulae, a rate of 63% (60 of 95) EndoAVF, and 37% (35 of 60) fistulae treated surgically. At 4 weeks, EndoAVF was not suitable for 2NC (defined as a palpable target vein [TV], 500 mL/min flow volume, and 5-mm diameter) underwent maturation procedures.ResultsTechnical success of EndoAVF creation was 96.7% (60 of 62). At 4 weeks, 67% (40 of 60) fistulae underwent maturation procedures: 62% (37 of 60) had balloon dilation, 32% (19 of 60) had brachial vein embolization, and 30% (18 of 60) had cubital vein banding, increasing TV flow volume from 182 ± 123 mL/min to 572 ± 225 mL/min (P < 0.0005). Transposition was required in 33% of patients (20 of 60), reducing the mean TV depth from 10.9 to 3.7 mm (P < .0001). 2NC and fistula success (2NC × 3) was achieved in 87% (47 of 54); 10% of patients (6 of 60) were not on dialysis; 6.8% of patients (4 of 60) died; 5% of fistulas (3 of 60) were abandoned for arm swelling, steal syndrome, and thrombosis. Time to 2NC, fistula success, and tunneled catheter removal were 65.6 ± 45.7 days, 79.1 ± 50.9 days, and 113.4 ± 62 days, respectively. Patients achieving 2NC had brachial artery flow of 944 ± 284 mL/min; and TV flow, diameter, and depth of 674 ± 292 mL/min, 6.1 ± 0.8 mm, and 3.6 ± 1.3 mm, respectively. Major complications were arm swelling, steal syndrome, and thrombosis.ConclusionsMost patients had EndoAVF with maturation procedures at 4 weeks that achieved rapid maturation (Ellipsys Fistula for Hemodialysis Access; NCT03828253).     

Phantom and Animal Study of a Robot-Assisted,CT-Guided Targeting System using Image-Only Navigation for Stereotactic Needle Insertion without Positional Sensors

PurposeTo evaluate the feasibility and accuracy of a robotic system to integrate and map computed tomography (CT) and robotic coordinates, followed by automatic trajectory execution by a robotic arm. The system was hypothesized to achieve a targeting error of <5 mm without significant influence from variations in angulation or depth.Materials and MethodsAn experimental study was conducted using a robotic system (Automated Needle Targeting device for CT [ANT-C]) for needle insertions into a phantom model on both moving patient table and moving gantry CT scanners. Eight spherical markers were registered as targets for 90 insertions at different trajectories. After a single ANT-C registration, the closed-loop software targeted multiple markers via the insertion of robotically aligned 18-gauge needles. Accuracy (distance from the needle tip to the target) was assessed by postinsertion CT scans. Similar procedures were repeated to guide 10 needle insertions into a porcine lung. A regression analysis was performed to test the effect of needle angulation and insertion depth on the accuracy of insertion.ResultsIn the phantom model, all needle insertions (median trajectory depth, 64.8 mm; range, 46.1–153 mm) were successfully performed in single attempts. The overall accuracy was 1.36 mm ± 0.53, which did not differ between the 2 types of CT scanners (1.39 mm ± 0.54 [moving patient table CT] vs 1.33 mm ± 0.52 [moving gantry CT]; P = .54) and was not significantly affected by the needle angulation and insertion depth. The accuracy for the porcine model was 9.09 mm ± 4.21.ConclusionsRobot-assisted needle insertion using the ANT-C robotic device was feasible and accurate for targeting multiple markers in a phantom model.     

Single-Session Treatment of Patients with Symptomatic Iliocaval and Iliofemoral Deep Vein Thrombosis: Technical Results of a Prospective Pilot Study

PurposeTo investigate the short-term results of single-session treatment of iliocaval and iliofemoral DVT using a single thrombectomy device.Materials and MethodsThis prospective pilot study analyzed patients with acute iliocaval or iliofemoral DVT treated in a single session using the JETi thrombectomy system. All analyses were performed on an intention-to-treat basis. The cohort consisted of 53 limbs in 47 patients (27 women), with a mean age of 57 years (range, 16–88 years). The primary safety and efficacy endpoints were freedom from major adverse events (MAEs) and reestablishment of unobstructed flow in a single session, respectively.ResultsThe mean duration of symptoms was 8.5 days ± SD 9.2, with 10 patients (11 limbs, 21.3%) presenting with a symptom duration of >14 days. Twelve (25.5%) patients had thrombosis of the inferior vena cava and the iliofemoral segments. During the index procedure, unobstructed flow was reestablished in 47 of 53 (88.6%) limbs in 41 of 47 (87.2%) patients (primary endpoint) with no MAEs through 30 days. Overall, unobstructed flow was restored in 50 of 53 (94.3%) limbs and in 44 of 47 (93.6%) patients.ConclusionsSuccessful single-session treatment of patients with acute iliocaval and iliofemoral DVT is feasible with a high rate of efficacy and a low rate of adverse events. Such patients may be treated on an outpatient basis.     

Pelvic Venous Disorders in Women due to Pelvic Varices: Treatment by Embolization: Experience in 520 Patients

PurposeThe purpose of this study was to determine the efficacy and safety of embolization treatment in pelvic venous disorders in women refluxing in the ovarian and or internal iliac veins in women with chronic pelvic pain.Materials and MethodsA retrospective study conducted from January 2000 to June 2017 in 617 patients diagnosed with pelvic venous disorders (PeVDs) with a mean age of 43.2 ± 7.2 years were treated using an embolization procedure. A total of 520 were included, and 97 patients were excluded. The main inclusion criteria were PeVD symptoms for more than 6 months and transvaginal Doppler ultrasonography (TV-DUS) diagnosis of varicose veins in the pelvis with a diameter greater than 6 mm. The main objective was to embolize the 4 main pelvic venous plexi (ovarian and internal iliac veins) whenever possible. Follow-up was performed using clinical symptoms (visual analog scale) and TV-DUS at 1, 3, 6, and 12 months and then every year up to 5 years.ResultsThe technical success (embolization of the 4 main pelvic veins) was achieved in 84.4% of the patients. The average follow-up was 58.7 ± 5.7 months. The visual analog scale was improved from 7.63 ± 0.9 points pretreatment to 0.91 ± 1.5 at 5 years. A total of 26 patients (5%) presented with symptom recurrence and pelvic varicose veins. There were 57 minor complications (10.9%) and 11 major complications (2.1%), with 7 cases (1.34%) of device migration to the lung.ConclusionsThe embolization of pelvic varicose veins is a safe and effective procedure. The selection of the embolic agents and the number of veins needed to be treated.     

Comparison of Fibered versus Nonfibered Coils for Venous Embolization in an Ovine Model

PurposeTo compare nylon fibered (F) with nonfibered (NF) coils for embolization in an ovine venous model.Materials and MethodsFour- to 8-mm-diameter, 0.035-inch F and NF coils were deployed in 24 veins in 6 sheep. The number of coils, total length of the coils, and length of implanted coil pack required to achieve complete stasis were recorded, as were vessel diameter, radiation dose, ease of packing, damage to embolized vessel, and time to stasis. Venography at 1 and 3 months was used to assess the migration and durability of vessel occlusion. Veins were harvested at 3 months.ResultsF and NF coils were deployed in 24 veins, and stasis was achieved, without immediate coil migration or vessel damage. The mean numbers of F and NF coils per vein were 5 and 8.75, respectively (P = .007). The vessel diameter between the groups was not statistically different. The total coil length (F, 70 cm vs NF, 122.5 cm; P = .0007), coil pack length (F, 29.3 mm vs NF, 39.4 mm; P = .003), time to stasis (F, 5.3 minutes vs NF, 9.0 minutes; P = .008), and radiation dose (F, 25.3 mGy vs NF, 34.9 mGy; P = .037) were significantly different between the groups. Challenges with the animal model prevented conclusive long-term results. Migration occurred with 8 of 11 (72%) coil packs in the femoral veins and 0 of 13 (0%) coil packs in the internal iliac and deep femoral veins. Venography demonstrated that of 16 remaining coil packs, 11 were occluded at 1 month and 10 remained occluded at 3 months.ConclusionsFibers allow for significantly fewer coils to achieve immediate venous occlusion.     

Transjugular Intrahepatic Portosystemic Shunt Creation Using a Radiofrequency Wire: Prospective Clinical Safety and Feasibility Trial in Cirrhosis

PurposeTo assess the safety and feasibility of using a radiofrequency (RF) wire for portosystemic shunt creation.Materials and MethodsTen patients undergoing elective creation of a transjugular intrahepatic portosystemic shunt (TIPS) or a direct intrahepatic portosystemic shunt (DIPS) were prospectively enrolled. Primary outcomes were the safety and feasibility of RF wire used for the creation of TIPS and DIPS. Median age was 66.5 ± 6.1 years. Causes of liver disease included alcohol (n = 5), nonalcoholic steatohepatitis (n = 2), hepatitis C virus (n = 1), primary biliary cirrhosis (n = 1), autoimmune hepatitis (n = 1). The median score for model for end-stage liver disease was 11 ± 4.3. The Rosch-Uchida TIPS set was used with intravascular ultrasonography guidance in all cases. A 0.035-inch RF wire was used in lieu of the trocar needle through the 5-F TIPS set catheter to create a track between the hepatic vein and the portal vein. All shunts were created using stent grafts.ResultsTechnical success rate was 100%. In 7 of 10 patients, portal vein access was achieved with a single pass. A DIPS was created in 2 patients based on anatomic favorability. Median fluoroscopy time was 13.3 ± 3.8 min, and median total procedure time was 102 ± 19 min. The wire passed through parenchyma without subjective deflection. There was 1 case of extracapsular puncture with no clinical consequence. The RF wire was too stiff to curve into the main portal vein, requiring wire exchange in all but 1 case. Mean portosystemic gradient decreased from 13.9 ± 3.3 to 5.9 ± 2.1 mm Hg. No immediate complications were encountered. Shunt patency was 100% at 30 days.ConclusionsCreation of TIPS and DIPS using an RF wire was safe and feasible, enabling creation of an intrahepatic track without subjective deflection in cirrhotic patients.     

Large-Bore Aspiration Thrombectomy versus Catheter-Directed Thrombolysis for Acute Pulmonary Embolism: A Propensity Score–Matched Comparison

PurposeTo compare effectiveness and safety of large-bore aspiration thrombectomy (LBAT) with catheter-directed thrombolysis (CDT) for treatment of acute massive and submassive pulmonary embolism (PE).Materials and MethodsThis retrospective review included patients with acute PE treated with LBAT or CDT using tissue plasminogen activator (tPA) between December 2009 and May 2020. A propensity score based on Pulmonary Embolism Severity Index class and PE severity (massive vs submassive) was calculated, and 26 LBAT cases (age 60.2 y ± 17.1, 14/26 women) were matched with 26 CDT cases (age 59.7 y ± 14.2, 14/26 women).ResultsThe CDT group had 22.1 mg ± 8.1 tPA infused over 21.2 h ± 6.6. Both groups demonstrated similar initial and final systolic pulmonary artery pressure (PAP) (LBAT: 54.5 mm Hg ± 12.9 vs CDT: 54.5 mm Hg ± 16.3, P = .8, and LBAT: 42.5 mm Hg ± 14.1 vs CDT: 42.6 mm Hg ± 12.1, P = .8, respectively) and similar reductions in heart rate (LBAT: −5.4 beats/min ± 19.2 vs CDT: −9.6 beats/min ± 15.8, P = .4). CDT demonstrated a higher reduction in Miller score (−10.1 ± 3.9 vs −7.5 ± 3.8, P = .02). LBAT resulted in 1 minor hemorrhagic complication and 2 procedure-related mortalities, and CDT resulted in 1 minor and 1 major hemorrhagic complication.ConclusionsLBAT and CDT resulted in similar reductions of PAP and heart rate when used to treat acute PE. CDT reduced thrombus burden to a greater degree. Although hemorrhagic complications rates were not significantly different, the LBAT group demonstrated a higher rate of procedure-related mortality. Larger studies are needed to compare the safety of these techniques.     

Single-Center Prospective Pilot Study of Sirolimus Drug-Coated Balloon Angioplasty in Maintaining the Patency of Thrombosed Arteriovenous Graft

PurposeTo investigate the use of a sirolimus drug-coated balloon (DCB) in the management of a thrombosed arteriovenous graft (AVG).Materials and MethodsA single-center prospective pilot study was conducted between October 2018 and October 2019. Twenty patients (age = 67.0 years ± 10; male = 35%; mean time on dialysis = 31 months) with thrombosed upper limb AVG were enrolled. After successful pharmacomechanical thrombectomy and adequate treatment of the graft vein junction, sirolimus DCB angioplasty was performed at the graft vein junction. The patients were followed-up for 6 months, and all adverse events occurring during the study period were recorded.ResultsThe primary circuit patency rates at 3 and 6 months were 76% and 65%, respectively, while the assisted-primary circuit patency rates at 3 and 6 months were 82% and 65%, respectively. The 3- and 6-month secondary circuit patency rates were 88% and 76%, respectively. Using Kaplan-Meier analyses, the estimated mean primary, assisted-primary, and secondary patencies were 285 days (95% confidence interval (CI) = 194–376 days), 319 days (95% CI = 221–416 days), and 409 days (95% CI = 333–485 days). No adverse event directly related to sirolimus DCB use was observed.ConclusionsThe results of this pilot study suggest that the application of sirolimus DCB at the graft vein junction after the successful thrombectomy of AVG may be a feasible option to improve patency outcomes.     

Endovascular Repair of Narrow Distal Aortas Using an In Situ Fenestration Technique

PurposeTo demonstrate that in situ fenestration (ISF) of an aorto-uni-iliac endograft to treat aortoiliac disease with narrow distal aorta (NDA) vessels is effective and safe.Materials and MethodsData for all patients treated by use of ISF between August 2014 and December 2019 were retrospectively analyzed. The series included 27 patients, aged 70 years ± standard error (SE) 11. The pathologies treated included aortoiliac occlusive disease (n = 16), asymptomatic abdominal aortic aneurysm (n = 8), and a ruptured abdominal aortic aneurysm (n = 3). The technique consisted of deploying an aorto-uni-iliac graft, which was converted into a bifurcated repair through contralateral iliac ISF. The inclusion criteria encompassed the presence of an abdominal aortic aneurysm (diameter of >50 mm, rapid growth, ruptured or symptomatic) associated with NDA or the presence of severe aortoiliac occlusive disease with NDA. NDA is defined as an aortic diameter of <16 mm.ResultsThe mean aortic bifurcation diameter was 11.9 mm ± SE 1.5. In total, 55% of the fenestrated endografts were performed with a multifilament polyester endograft and 45% with expanded polytetrafluoroethylene endograft. Technical success was 100%. Fluoroscopy time was 28 minutes ± SE 12, and 94 mL ± SE 43 of iodinated contrast medium was used. In the postoperative course, a single minor retroperitoneal hematoma was identified. The mean hospital stay was 5 days ± SE 3. At the mean follow-up of 26 months ± SE 22, overall primary patency was 94% and no endoleak was observed at the ISF site.ConclusionsThe ISF technique is safe and effective in the treatment of aortoiliac disease with NDA. Comparisons with alternative techniques are needed to determine the long-term durability.     

Anatomical Variations of the Left Adrenal Vein Encountered During Venous Sampling

PurposeTo identify anatomical variations in the left adrenal vein (LAV) and to evaluate the role of preprocedural contrast-enhanced computed tomography (CT) planning.MethodsThe length of the left adrenal central vein (LACV), the vessel that receives blood from all tributaries of the left adrenal gland, was measured using venograms of patients who had undergone adrenal venous sampling (AVS) for the diagnosis of primary aldosteronism between October 2017 and December 2019. The anatomical variants of the LAV were described and classified. Contrast-enhanced CT was used to evaluate the detection rate of the following: (a) confluence of the left inferior phrenic vein and the LAV and (b) the last tributary flowing into the LAV.ResultsIn total, 311 patients (143 men, 168 women; mean age: 49.3 years ± 11.0) were enrolled. Of them, 9 (2.9%) patients had anatomical variants lacking a LACV. In patients with a LACV (n = 302), the venographic LACV length was 9.0 mm ± 3.9 (<1 mm in 9 patients). The detection rate of the confluence of the left inferior phrenic vein and LAV, as determined using contrast-enhanced CT, was high (96.2%), whereas that of the last tributary flowing into the LAV was low (0.8%). In 4 of 18 patients with short or absent LACV, the variant was visualized using contrast-enhanced CT.ConclusionsIn some patients, the LACV is absent or short, which is an anatomical variation. Understanding venographic anatomical variations can help avoid misleading results resulting from a suboptimal sampling site in AVS. For some subtypes, contrast-enhanced CT may also help in planning the AVS procedure.     

4D Flow MR Imaging to Improve Microwave Ablation Prediction Models: A Feasibility Study in an In Vivo Porcine Liver

PurposeTo characterize the effect of hepatic vessel flow using 4-dimensional (4D) flow magnetic resonance (MR) imaging and correlate their effect on microwave ablation volumes in an in vivo non-cirrhotic porcine liver model.Materials and MethodsMicrowave ablation antennas were placed under ultrasound guidance in each liver lobe of swine (n = 3 in each animal) for a total of 9 ablations. Pre- and post-ablation 4D flow MR imaging was acquired to quantify flow changes in the hepatic vasculature. Flow measurements, along with encompassed vessel size and vessel-antenna spacing, were then correlated with final ablation volume from segmented MR images.ResultsThe linear regression model demonstrated that the preablation measurement of encompassed hepatic vein size (β = –0.80 ± 0.25, 95% confidence interval [CI] –1.15 to –0.22; P = .02) was significantly correlated to final ablation zone volume. The addition of hepatic vein flow rate found via 4D flow MRI (β = –0.83 ± 0.65, 95% CI –2.50 to 0.84; P = .26), and distance from antenna to hepatic vein (β = 0.26 ± 0.26, 95% CI –0.40 to 0.92; P = .36) improved the model accuracy but not significantly so (multivariate adjusted R² = 0.70 vs univariate (vessel size) adjusted R² = 0.63, P = .24).ConclusionsHepatic vein size in an encompassed ablation zone was found to be significantly correlated with final ablation zone volume. Although the univariate 4D flow MR imaging-acquired measurements alone were not found to be statistically significant, its addition to hepatic vein size improved the accuracy of the ablation volume regression model. Pre-ablation 4D flow MR imaging of the liver may assist in prospectively optimizing thermal ablation treatment.     

Iliocaval Skip Stent Reconstruction Technique for Chronic Bilateral Iliocaval Venous Occlusion

PurposeTo report safety and efficacy of a skip stent technique using nitinol stents in patients with chronic bilateral iliocaval venous occlusions.Materials and MethodsA retrospective analysis of 48 consecutive patients (32 men; mean age, 40.7 years; age range, 18–68 years) with chronic bilateral iliocaval obstructions treated using a nonoverlapping stent technique was conducted at a single center. None of the patients had May-Thurner syndrome. Iliocaval confluence was treated by deploying a nitinol stent in inferior vena cava (IVC) and a nitinol stent in each common iliac vein close to the caval stent. Patency of stents was assessed by duplex US at 2 weeks, 3 months, and 6 months and yearly thereafter.ResultsRecanalization and stent reconstruction was technically successful in 47 (98%) patients. The sinus-XL venous stent was used to treat IVC (95 [100%]). Common iliac and external iliac veins were treated with sinus-Venous and VENOVO stents (80 [83%] and 16 [17%] limbs, respectively). External iliac and common femoral veins were treated with sinus-Venous and VENOVO stents (83 [92%] and 7 [18%] limbs, respectively). Early thrombosis (< 30 days) of the iliac vein with stent occurred in 2 limbs. Cumulative primary, assisted primary, and secondary patency rates at 30 months were 74%, 83%, and 97%.ConclusionsFindings of this study suggest that leaving a skipped lesion at the level of iliocaval confluence may not adversely affect stent patency. Patency rates were comparable with other reported techniques of stent reconstruction at the level of iliocaval confluence.     

Woodchuck Hepatic Anatomy and Vascular Alterations Due to Hepatocellular Carcinoma with Angiographic Atlas of the Abdomen and Pelvis

PurposeTo characterize the hepatic and abdominal angiographic anatomy of woodchucks and vascular changes associated with hepatocellular carcinoma (HCC).Materials and MethodsTwenty-nine woodchucks (23 with viral-associated HCC, 6 without) underwent multiphasic computed tomography (CT). Fourteen woodchucks (8 with HCC) also underwent diagnostic angiography. Hepatic arterial diameters were measured on the CT scans. Woodchucks were divided into 3 groups: non–tumor-bearing, largest tumor supplied by the right hepatic artery (RHA), and largest tumor supplied by the left hepatic artery (LHA). Statistical analysis with a repeated measures model was performed to determine the effects of tumor location (right, left), vessel measured (RHA, LHA), and interaction between the 2 on vessel diameter. Lobar arteries supplying HCC were compared with those that did not.ResultsCT anatomy and normal and variant vascular anatomy were defined. In woodchucks with HCC, LHA and RHA supplying tumors had mean diameters of 2.0 mm ± 0.3 and 1.6 mm ± 0.3 versus 1.5 mm ± 0.3 and 1.1 mm ± 0.2 for non–tumor-supplying arteries (P = .0002 and P < .0001), respectively. Lobar arteries supplying tumors were similarly ectatic. The right lateral lobe artery had the most profound increase in the mean diameter when supplying tumors, measuring 1.7 mm ± 0.1 versus 1.0 mm ± 0.1 in the non–tumor-supplying artery (P < .0001). There were no differences in the diameters of the aorta and celiac, common, and proper hepatic arteries between tumor- and non–tumor-bearing woodchucks. An angiographic atlas of the abdominal vessels was generated.ConclusionsHCC tumoral vasculature in woodchucks was ectatic compared with normal vasculature. This phenomenon recapitulates human HCC and may facilitate investigation of transcatheter and drug delivery therapies in an HCC animal model.     

Preoperative Arterial Embolization for Heterotopic Ossification of the Hip

PurposeTo investigate the efficacy and safety of preoperative arterial embolization for neurogenic heterotopic ossification (NHO) of the hip.Materials and MethodsThis single-center retrospective study reviewed outcomes in 16 consecutive patients who had surgical resection of NHO of the hip: 8 of whom underwent preoperative arterial embolization and 8 of whom did not. Both patient cohorts had similar baseline characteristics. A mean of 2.62 ± 1.9 arteries per patient, including the gluteal, lateral circumflex femoral, and deep circumflex iliac branches, were embolized using an n-butyl cyanoacrylate (NBCA)–ethiodized oil mixture. Data from both cohorts regarding intraoperative blood loss, volume of blood transfused, complications, and duration of hospitalization were compared.ResultsA mean of 2.6 ± 1.9 arteries were embolized with NBCA–ethiodized oil, mainly the gluteal arteries, lateral circumflex femoral artery, and deep circumflex iliac artery. In the embolization group, mean intraoperative blood loss was 875 mL ± 320, mean number of units of blood used was 0.5 ± 0.7, and mean number of days of hospitalization was 6.4 days ± 1.6. In the control group, mean intraoperative blood loss was 1,350 mL ± 120, mean number of units of blood used was 2 ± 1.1, and average number of days of hospitalization was 11.5 days ± 1.4. The embolization group had a mean reduction in blood loss of 40.7% (P = 0.035), reduction in units of blood administered of 75% (P = 0.021), and reduction in days of hospitalization of 44.7% (P = 0.014). No procedural complications were recorded.ConclusionsPreoperative arterial embolization is effective and safe in reducing intraoperative blood loss, number of hospitalization days, and need for blood transfusions in surgical resection of NHO of the hip.