Current Evidence for Endovascular Therapies in the Management of Acute Deep Vein Thrombosis.

Acute lower extremity deep vein thrombosis (DVT), specifically proximal iliofemoral DVT, is a relatively common disorder that can result in a chronic debilitating post-thrombotic syndrome (PTS), with a significant effect on a patient's quality of life. Anticoagulation is first-line therapy; however, percutaneous interventions have emerged as treatment options for patients where there is concern that anticoagulation alone will not resolve the DVT as well as prevent PTS. This paper will discuss the existing data on these interventions and review current endovascular techniques, including catheter-directed thrombolysis, pharmacomechanical thrombectomy, and large-bore mechanical thrombectomy in the management of DVT.

Performance Evaluation of a Miniature and Disposable Endovascular Robotic Device.

PURPOSE: The LIBERTY® Robotic System is a miniature, single-use device designed to facilitate remote-controlled navigation to intravascular targets. We aim to evaluate the robot's performance to manipulate a range of microguidewires and microcatheters during percutaneous endovascular procedures. MATERIALS AND METHODS: Six interventional radiologists performed selective robotic-assisted catheterization of eight pre-determined vascular targets in a pig model. The navigation time from the guiding catheter tip to the target vessel was recorded. Each physician with a clinical experience of 20 years completed a questionnaire to evaluate the ease of use, accuracy, and safety of the robotic operation. RESULTS: Most of the physicians reached the vascular targets in less than one minute. There was no angiographic evidence of vascular injury such as artery laceration or contusion. All physicians reported consensus about the high performance of the robot. CONCLUSION: The miniature disposable robot is effective at reaching a range of vessels in a porcine model. Physicians found the device intuitive and easy to operate remotely.

Safety of Irreversible Electroporation Ablation of the Pancreas.

OBJECTIVES: To evaluate the safety of irreversible electroporation (IRE) on swine pancreatic tissue including its effects on peripancreatic vessels, bile ducts, and bowel. METHODS: Eighteen Yorkshire pigs underwent IRE ablation of the pancreas successfully and without clinical complications. Contrast-enhanced computed tomography angiography and laboratory studies before the IRE ablation with follow-up computed tomography angiography, laboratory testing, and pathological examination up to 4 weeks postablation were performed. RESULTS: In a subset of cases, anatomic peripancreatic vessel narrowing was seen by 1 week postablation, persisting at 4 weeks postablation, without apparent functional impairment of blood flow. Laboratory studies revealed elevated amylase and lipase at 24 hours post-IRE, suggestive of acute pancreatitis, which normalized by 4 weeks post-IRE. There was extensive pancreatic tissue damage 24 hours after IRE with infiltration of immune cells, which was gradually replaced by fibrotic tissue. Ductal regeneration without loss of pancreatic acinar tissue and glandular function was observed at 1 and 4 weeks postablation. CONCLUSIONS: In our study, we demonstrated and confirmed the safety and minimal complications of IRE ablation in the pancreas and its surrounding vital structures. These results show the potential of IRE as an alternative treatment modality in patients with pancreatic cancer, especially those with locally advanced disease.

Transcatheter Embolization of Renal-Splenic Shunt to Treat Hematemesis.

Although sequelae of chronic liver disease are the most common causes of altered pressure dynamics in the portal and splanchnic circulations, there are other mechanisms resulting in increased venous pressures with subsequent development of splenic and gastric varices. We report a case of a patient without portal hypertension, but with bleeding gastric varices with a presumed splenorenal shunt (SRS) on CT. Venography revealed flow reversal through the shunt (directed from the renal vein, into the splenic vein and out the portal vein; a renal-splent shunt (RSR)) and thus an anatomically similar but functionally distinct systemic to mesenteric variant. While being anatomically similar to the well-known SRS, the different flow dynamics necessitate a different approach for treatment and important considerations for the use of any liquid embolic.

Retrograde Transvenous Obliteration (RTO): A New Treatment Option for Hepatic Encephalopathy.

Hepatic Encephalopathy (HE) is a complication of liver disease, consisting of brain dysfunction often due to portosystemic shunting of blood flow in the liver. HE can range from minimal HE, presenting with normal neurological function, to overt HE, with neurological and neuropsychiatric abnormalities. Various clinical grading systems are used to differentiate HE to provide the appropriate treatments. Traditional treatment of HE aims to identify and resolve precipitating factors through targeting hyperammonemia and administering antibiotics or probiotics. While retrograde transvenous obliteration (RTO), including balloon-occluded retrograde transvenous obliteration, coil-assisted retrograde transvenous obliteration or plug-assisted retrograde tranvenous obliteration, is an established procedure to manage gastric varices, little is known about its potential to treat HE. RTO is a procedure to occlude a spontaneous portosystemic shunt, minimizing shunting of portal blood to systemic circulation. Though there is not a large study with HE patients who have undergone RTO; the results appear promising in reducing HE. Side effects, however, should be considered in the treatment of HE such as the transient worsening of portal hypertension and the formation of additional shunts. While additional studies are needed to assess the long-term success, RTO appears to be an effective alternative method to alleviate clinical symptoms of HE when pharmacological therapies and other conservative medical managements have failed.

Comparison of Ferumoxytol-enhanced MR Angiography and CT Angiography for the Detection of Pulmonary Arteriovenous Malformations in Hereditary Hemorrhagic Telangiectasia: Initial Results.

PURPOSE: To perform a preliminary comparison of the sensitivity and positive predictive value of ferumoxytol-enhanced MR angiography with those of CT angiography for detection of pulmonary arteriovenous malformations (AVMs) in hereditary hemorrhagic telangiectasia (HHT). MATERIALS AND METHODS: Institutional review board approval and informed patient consent were obtained. Ten patients with pulmonary AVMs who had undergone CT of the chest within 12 months underwent MRI of the chest and abdomen with ferumoxytol at 3.0 T at a dose of 4 mg per kilogram of body weight. Consensus review of MR and CT images assessed the presence and characteristics of pulmonary AVMs, image quality, vessel visibility, and artifact grade. RESULTS: Forty-three AVMs were detected, 13 native and 30 recanalized. Twenty-one AVMs had a feeding artery diameter of greater than 2 mm, of which detection occurred in 19 (at MRI and CT), in two (at MRI only), and zero (at CT only). Twenty-two AVMs had a feeding artery diameter of less than or equal to 2 mm, of which detection occurred in 16 (at MRI and CT), six (at CT only), and zero (at MRI only). For the entire cohort, the sensitivity of ferumoxytol-enhanced MRI using CT as the reference standard was 85.4% (35 of 41), and the positive predictive value was 100% (35 of 35). No significant difference was found between CT and MRI in AVM size, feeding artery and draining vein diameter, and artifact score (P >.05 for all). CONCLUSION: Initial results suggest that ferumoxytol-enhanced MRI is a feasible alternative to CT for detection of pulmonary AVM in HHT, while avoiding repeated exposure to radiation, nephrotoxic contrast material, or gadolinium-based contrast agent.© RSNA, 2020.

Renal denervation as adjunctive therapy to cardiac sympathetic denervation for ablation refractory ventricular tachycardia.

BACKGROUND: Autonomic modulation is finding an increasing role in the treatment of ventricular arrhythmias. Renal denervation (RDN) has been described as a treatment modality for refractory ventricular tachycardia (VT) in case series. OBJECTIVE: The purpose of this study was to evaluate RDN as an adjunctive therapy to cardiac sympathetic denervation (CSD) for ablation refractory VT. METHODS: Patients who underwent RDN after radiofrequency ablation and CSD procedures at our center from 2012 to 2019 were evaluated. RESULTS: Ten patients underwent RDN after CSD (9 bilateral and 1 left-sided only) with a median follow-up of 23 months. The mean age was 59.9 ± 10.4 years, and 9/10 (90%) were men. All had cardiomyopathy with a mean ejection fraction of 33% ± 11% (20% ischemic). Four (40%) underwent CSD during the same hospitalization as that for RDN. Patients who underwent RDN as adjunctive therapy to CSD had a decrease in all implantable cardioverter-defibrillator therapies (shocks + antitachycardia pacing [ATP]) from 29.5 ± 25.2 to 7.1 ± 10.1 comparing 6 months pre-RDN to 6 months post-RDN (P = .028). Implantable cardioverter-defibrillator shocks were significantly decreased from 7.0 ± 6.1 to 1.7 ± 2.5 comparing 6 months pre-RDN to 6 months post-RDN (P = .026). This benefit was driven by a decrease in therapies for 6 patients who had a staged procedure, not performed during the same hospitalization (28.5 ± 24.3 to 1.0 ± 1.2; P = .043). CONCLUSION: RDN demonstrates the potential benefit when VT recurs after radiofrequency ablation and CSD. The benefit is seen in patients who undergo a staged procedure. The need for acute RDN after CSD portends a poor prognosis.

Transjugular Liver Biopsy: Safe Even in Patients With Severe Coagulopathies and Multiple Biopsies.

OBJECTIVES: To investigate the safety profile and diagnostic efficacy of transjugular liver biopsy (TJLB), with a focus on patients with severe coagulopathies and with multiple biopsies. METHODS: Clinical, laboratory, and demographic information was collected on 1,321 TJLBs in 932 patients (mean age 43.5 ± 23.2 years) performed between January 2009 and May 2017 to determine the diagnostic success rate and incidence of both major and minor complications in the 3-day and 30-day period post-biopsies. These outcomes were also analyzed for severely coagulopathic patients and a subgroup of patients who underwent multiple biopsies. RESULTS: The overall success rate (diagnostic yield) of the TJLB procedure was 97.7% (1,291/1,321). Overall, the major and minor complication rates were 1.0% (13/1,321) and 9.5% (126/1,321), respectively. In patients with multiple biopsies, the overall complication rate was similar to the entire study cohort, which was 10.4% (57/550). Patients were also stratified according to the platelet counts of 0-50, 51-100, 101-200, 201-300 and >300 × 10 platelets/µL. The overall complication rates were 8.0% (10/124), 11.6% (36/310), 9.9% (54/547), 11.9% (28/235), and 14.3% (11/77), respectively, and these were not statistically significant from each other. Patients were also stratified by international normalized ratio into 0-1, 1.1-2, 2.1-3, and >3. The overall complication rates of these patients were 8.0% (19/237), 11.8% (113/954), 16.3% (7/43), and 0% (0/9), respectively, and were not statistically significant from each other. DISCUSSION: TJLB is a highly efficacious, well-tolerated and safe procedure. It can be safely performed multiple times in the same patient or in critically ill, severely coagulopathic patients with no significant increase in the rate of complication while maintaining an extremely favorable diagnostic yield.

Salvage of renal transplant with vacuum-assisted thrombectomy of large iliocaval and allograft venous outflow thrombus.

A 47-year-old male with a remote renal transplant due to pediatric glomerulonephritis on oral anticoagulation for symptomatic deep venous thrombosis and pulmonary emboli presented with sudden hip and groin pain. The patient was found to have a spinal epidural hematoma, underwent reversal of anticoagulation, and subsequently developed worsening renal function. Imaging revealed occlusive iliocaval venous thrombosis with extension to the renal allograft. Given risk of epidural hematoma expansion, the patient was deemed high risk for thrombolysis. The AngioVac system was used for single session thrombus removal. The patient's renal function improved and no focal neurologic sequelae was noted postprocedure. Six-month follow-up showed persistent vessel patency.

Management Options for Gastric Variceal Hemorrhage.

IMPORTANCE: Varices are one of the main clinical manifestations of cirrhosis and portal hypertension. Gastric varices are less common than esophageal varices but are often associated with poorer prognosis, mainly because of their higher propensity to bleed. OBSERVATIONS: Currently, treatments used to control and manage gastric variceal bleeding include ß-blockers, endoscopic injection sclerotherapy, endoscopic variceal ligation, endoscopic variceal obturation, shunt surgery, transjugular intrahepatic portosystemic shunts, balloon-occluded retrograde transvenous obliteration (BRTO), and modified BRTO. In the past few decades, Western (United States and Europe) interventional radiologists have preferred transjugular intrahepatic portosystemic shunts that aim to decompress the liver and reduce portal pressure. Conversely, Eastern radiologists (Japan and South Korea) have preferred BRTO that directly targets the gastric varices. Over the past 20 years, BRTO has evolved and procedure-related risks have decreased. Owing to its safety and efficiency in treating gastric varices, BRTO is now starting to gain popularity among Western interventional radiologists. In this review, we present a comprehensive literature review of current and emerging management options, including BRTO and modified BRTO, for the treatment of gastric varices in the setting of cirrhosis and portal hypertension. CONCLUSIONS AND RELEVANCE: Balloon-occluded retrograde transvenous obliteration has emerged as a safe and effective alternative treatment option for gastric variceal hemorrhage. A proper training, evidence-based consensus and guideline, thorough preprocedural and postprocedural evaluation, and a multidisciplinary team approach with BRTO and modified BRTO are strongly recommended to ensure best patient care.

High resolution, 3-dimensional Ferumoxytol-enhanced cardiovascular magnetic resonance venography in central venous occlusion.

BACKGROUND: Although cardiovascular magnetic resonance venography (CMRV) is generally regarded as the technique of choice for imaging the central veins, conventional CMRV is not ideal. Gadolinium-based contrast agents (GBCA) are less suited to steady state venous imaging than to first pass arterial imaging and they may be contraindicated in patients with renal impairment where evaluation of venous anatomy is frequently required. We aim to evaluate the diagnostic performance of 3-dimensional (3D) ferumoxytol-enhanced CMRV (FE-CMRV) for suspected central venous occlusion in patients with renal failure and to assess its clinical impact on patient management. METHODS: In this IRB-approved and HIPAA-compliant study, 52 consecutive adult patients (47 years, IQR 32-61; 29 male) with renal impairment and suspected venous occlusion underwent FE-CMRV, following infusion of ferumoxytol. Breath-held, high resolution, 3D steady state FE-CMRV was performed through the chest, abdomen and pelvis. Two blinded reviewers independently scored twenty-one named venous segments for quality and patency. Correlative catheter venography in 14 patients was used as the reference standard for diagnostic accuracy. Retrospective chart review was conducted to determine clinical impact of FE-CMRV. Interobserver agreement was determined using Gwet's AC1 statistic. RESULTS: All patients underwent technically successful FE-CMRV without any adverse events. 99.5% (1033/1038) of venous segments were of diagnostic quality (score ≥ 2/4) with very good interobserver agreement (AC1 = 0.91). Interobserver agreement for venous occlusion was also very good (AC1 = 0.93). The overall accuracy of FE-CMRV compared to catheter venography was perfect (100.0%). No additional imaging was required prior to a clinical management decision in any of the 52 patients. Twenty-four successful and uncomplicated venous interventions were carried out following pre-procedural vascular mapping with FE-CMRV. CONCLUSIONS: 3D FE-CMRV is a practical, accurate and robust technique for high-resolution mapping of central thoracic, abdominal and pelvic veins and can be used to inform image-guided therapy. It may play a pivotal role in the care of patients in whom conventional contrast agents may be contraindicated or ineffective.

A reality check in transradial access: a single-centre comparison of transradial and transfemoral access for abdominal and peripheral intervention.

OBJECTIVES: The purpose of this study was to describe a single institution's experience with transradial access (TRA) for angiographic interventions, and to compare technical success, complication rate and radiation dose of procedures performed with TRA to those performed with transfemoral access (TFA). METHODS: A retrospective cohort study of patients undergoing peripheral interventions via TRA or TFA from 2015 to 2017 was performed. The cohort comprised 33 patients undergoing 44 procedures via TRA and 37 patients undergoing 44 procedures via TFA. Outcome measures were technical success, access-related complications, fluoroscopy time and radiation exposure. Differences at p < 0.05 were considered to be statistically significant. RESULTS: Baseline characteristics were similar between patients who had procedures via TRA versus those who had procedures via TFA, including age, sex and body mass index. Technical success was achieved in 41/44 (93.2%) of procedures performed via TRA, compared to 44/44 (100%) of procedures performed via TFA (p = 0.241). There were three access-related complications (6.8%) when TRA was performed, compared to none when TFA was performed (p = 0.241). Fluoroscopy time was longer in procedures performed with TRA compared to those performed with TFA (27.3 vs 20.4, p = 0.033). Dose area product (DAP) did not differ with access site choice (p = 0.186). CONCLUSIONS: TRA is a safe and feasible alternative to TFA for a range of peripheral interventions. However, TRA must be performed with prudence as it is not without complications and is technically challenging, leading to longer fluoroscopy time. KEY POINTS: • Transradial access (TRA) is feasible in a variety of peripheral interventions, achieving success in 93.2% of cases. • Access-related complications are comparable between transfemoral access (TFA) and TRA (p = 0.241), but prudence must be taken during TRA as it could be technically challenging. • Procedures performed with TRA tend to have longer fluoroscopy time compared to those performed with TFA (p = 0.033), but the DAPs are comparable (p = 0.186).

Interventional Oncology: Keeping Out of Trouble in Ablation Techniques.

Interventional radiologists provide an essential role in the therapy and management of cancer patients. Computed-tomography (CT) guided percutaneous procedures have enabled interventionalists to treat multiple solid organ malignancies with minimal risk, however, certain lesions may present challenges to physicians due to a difficult approach, or their close proximity to other vital structures. The following presents a brief summary of tips and tricks the interventionalist may use to provide their patients with safe and effective therapy.

Portal Venous Interventions: How to Recognize, Avoid, or Get Out of Trouble in Transjugular Intrahepatic Portosystemic Shunt (TIPS), Balloon Occlusion Sclerosis (ie, BRTO), and Portal Vein Embolization (PVE).

Portal venous interventions comprise a large portion of many Interventional Radiology practices today, and remain some of the more technically challenging cases in one's repertoire of procedures. The patients upon whom these procedures are performed are often critically ill, have decompensated disease, or are burdened with comorbid conditions such that they are poor surgical candidates. This leaves them with few options outside the care of Interventional Radiology. Some portal venous interventions, such as transjugular intrahepatic portosystemic shunt, have an established history of excellent clinical success with numerous technical advancements over the years helping to improve outcomes. Others, like balloon occlusion sclerotherapy or portal venous recanalization, are less well established but are nonetheless invaluable in the treatment of portal venous diseases. The goal of this article is to help dispel some of the anxiety experienced by individuals performing the three main procedures of the portal venous system, namely transjugular intrahepatic portosystemic shunt, balloon-occlusion retrograde transvenous obliteration, and portal vein embolization.

Venographic Analysis of Portal Flow After TIPS Predicts Future Shunt Revision.

OBJECTIVE: The purpose of this study was to investigate a new method-the portal vein enhancement curve-for quantifying portal vein blood flow immediately at transjugular intrahepatic portosystemic shunt (TIPS) creation using digital subtraction angiography images and its potential usefulness as a predictor of TIPS revision. CONCLUSION: The portal vein flow time constant, Qτ, was significantly different (p = 0.002) between patients grouped by 12-month revision (TIPS angioplasty, TIPS reduction, no revision); Qτ was higher in patients who required TIPS reduction.

Coil-Assisted Retrograde Transvenous Obliteration (CARTO): An Alternative Treatment Option for Refractory Hepatic Encephalopathy.

BACKGROUND: Overt hepatic encephalopathy (OHE) is a serious complication of liver dysfunction, which is associated with severe morbidity/mortality and healthcare resource utilization. OHE can be medically refractory due to spontaneous portosystemic shunts (SPSSs) and therefore a new treatment option for these SPSSs is critical. METHODS: This is a retrospective study of 43 patients with medically refractory OHE, who underwent CARTO (Coil-Assisted Retrograde Transvenous Obliteration) procedures between June 2012 and October 2016. The patient demographic characteristics, technical and clinical outcomes with an emphasis on HE improvement, and complications are reviewed and analyzed. RESULTS: The overall clinical success rate was 91% with a significant HE improvement. Eighty-one percent of patients had clinically significant improvement from OHE and 67% of patients had complete resolution of their HE symptoms during our follow-up period of 893 ± 585 days (range 36-1881 days, median 755.0 days). The median WH score improved from 3 (range 2-4) pre-CARTO to 1 (range 0-4) post-CARTO (p < 0.001). The median ammonia level significantly decreased from 134.5 pre-CARTO to 70.0 post-CARTO (p < 0.001) in 3 days. The overall mean survival was 1465.5 days (95% CI of 1243.0 and 1688.0 days). Only three patients had recurrent HE symptoms. There were 39.6% minor complication rate including new or worsened ascites and esophageal varices, and only 2.3% major complication rate requiring additional treatment (one patient with bleeding esophageal varices requiring treatment). No procedure-related death is noted. CONCLUSIONS: CARTO appears to be a safe and effective treatment option for refractory overt hepatic encephalopathy (OHE) due to spontaneous portosystemic shunts. CARTO could be an excellent addition to currently available treatment options for these patients.

Percutaneous Transthoracic Treatment of Ascending Aortic and Root Pseudoaneurysms: Procedural Aspects and Guidance with the Use of Multimodality Imaging.

Open repair of ascending aortic pseudoaneurysms (AAPs) is currently the standard of care, but it is associated with high morbidity and mortality. A single-center retrospective experience of 4 patients after cardiac surgery undergoing 5 percutaneous transthoracic embolization procedures is presented. In 3 of the 4 patients, the primary outcome of complete thrombosis was achieved after the first procedure, with a mean follow-up time of 11.5 months. In all 5 procedures, the patients tolerated the procedure well without associated acute complications. Percutaneous transthoracic embolization of AAPs offers an alternate minimally invasive treatment pathway for prohibitive-risk candidates.

Pharmacomechanical Catheter-Directed Thrombolysis for Deep-Vein Thrombosis.

BACKGROUND: The post-thrombotic syndrome frequently develops in patients with proximal deep-vein thrombosis despite treatment with anticoagulant therapy. Pharmacomechanical catheter-directed thrombolysis (hereafter "pharmacomechanical thrombolysis") rapidly removes thrombus and is hypothesized to reduce the risk of the post-thrombotic syndrome. METHODS: We randomly assigned 692 patients with acute proximal deep-vein thrombosis to receive either anticoagulation alone (control group) or anticoagulation plus pharmacomechanical thrombolysis (catheter-mediated or device-mediated intrathrombus delivery of recombinant tissue plasminogen activator and thrombus aspiration or maceration, with or without stenting). The primary outcome was development of the post-thrombotic syndrome between 6 and 24 months of follow-up. RESULTS: Between 6 and 24 months, there was no significant between-group difference in the percentage of patients with the post-thrombotic syndrome (47% in the pharmacomechanical-thrombolysis group and 48% in the control group; risk ratio, 0.96; 95% confidence interval [CI], 0.82 to 1.11; P=0.56). Pharmacomechanical thrombolysis led to more major bleeding events within 10 days (1.7% vs. 0.3% of patients, P=0.049), but no significant difference in recurrent venous thromboembolism was seen over the 24-month follow-up period (12% in the pharmacomechanical-thrombolysis group and 8% in the control group, P=0.09). Moderate-to-severe post-thrombotic syndrome occurred in 18% of patients in the pharmacomechanical-thrombolysis group versus 24% of those in the control group (risk ratio, 0.73; 95% CI, 0.54 to 0.98; P=0.04). Severity scores for the post-thrombotic syndrome were lower in the pharmacomechanical-thrombolysis group than in the control group at 6, 12, 18, and 24 months of follow-up (P<0.01 for the comparison of the Villalta scores at each time point), but the improvement in quality of life from baseline to 24 months did not differ significantly between the treatment groups. CONCLUSIONS: Among patients with acute proximal deep-vein thrombosis, the addition of pharmacomechanical catheter-directed thrombolysis to anticoagulation did not result in a lower risk of the post-thrombotic syndrome but did result in a higher risk of major bleeding. (Funded by the National Heart, Lung, and Blood Institute and others; ATTRACT ClinicalTrials.gov number, NCT00790335 .).