Prospective Margin Estimates Predict Local Tumor Progression Following Microwave Ablation of Small Renal Masses.

PURPOSE: To evaluate the relationship between prospectively generated ablative margin estimates and local tumor progression (LTP) among patients undergoing microwave ablation (MWA) of small renal masses (SRMs). MATERIALS AND METHODS: Between 2017 and 2020, patients who underwent MWA for SRM were retrospectively identified. During each procedure, segmented kidney and tumor shapes were coregistered with intraprocedural helical CT images obtained after microwave antenna placement. Predicted ablation zone shape and size were then overlaid onto the resultant model, and a model-to-model distance algorithm was employed to calculate multiple ablative margin estimates. LTP was modeled as a function of each margin estimate by hazard regression. Models were evaluated using hazard ratios and Akaike information criterion. Receiver operating characteristic curve area under the curve was also estimated using Harrell's and Uno's C indices (HI and UI, respectively). RESULTS: One hundred and twenty-eight patients were evaluated (median age 72.1 years). Mean tumor diameter was 2.4 ± 0.9 cm. LTP was observed in nine (7%) patients. Analysis showed that decreased estimated margin size as measured by first quartile (Q1; 25th percentile), maximum, and average ablative margin metrics was significantly associated with risk of LTP. For every one millimeter increase in Q1, maximum, and mean ablative margin, the hazard of LTP increased 67% (HR: 1.67; 95% CI = 1.25-2.20, UI = 0.93, HI = 0.77), 32% (HR: 1.32; 95% CI 1.09-1.60; UI = 0.93; HI = 0.76), and 48% (HR: 1.48; 95% CI 1.18-1.85; UI = 0.83; HI = 0.75), respectively. CONCLUSION: Prospectively generated ablative margin estimates can be used to predict the risk of local tumor progression following microwave ablation of small renal masses. LEVEL OF EVIDENCE 3: Retrospective cohort study.

A Pilot Study of Accelerometer-Based Biometric Data Collection among Patients Undergoing Locoregional Therapies.

This study evaluated the feasibility of measuring patient recovery after locoregional therapies (LRTs) using a wearable activity tracker (WAT). Twenty adult patients with cancer were provided with a WAT device to wear for a minimum of 7 days prior to their procedure (baseline) and for up to 30 days after their procedure (recovery). Daily step counts were continuously recorded. Patient responses to the Short Form 36-Item Health Survey (SF-36) were also collected before and after LRT. Analysis of WAT data demonstrated a mean of 4,850 daily steps taken at baseline, which decreased to 2,000 immediately after LRT and then rapidly increased to approximately 4,300 daily steps over an average of 10 days (P < .001). No significant changes were observed in SF-36 responses between baseline and follow-up assessments (P > .10). These results suggest that WAT devices capture dynamic periprocedural data not reflected in survey-based assessments and may be used to monitor patient recovery after interventional oncologic procedures.

Acute Lower Gastrointestinal Bleeding: Temporal Factors Associated With Positive Findings on Catheter Angiography After (99m)Tc-Labeled RBC Scanning.

OBJECTIVE: The objective of the study was to determine if time to positive (TTP), defined as the time from the start of (99m)Tc-labeled RBC scanning to the appearance of a radionuclide blush (considered to be a positive finding for acute lower gastrointestinal bleeding [LGIB]), and lag time (LT), defined as the time from the appearance of a radionuclide blush to the start of catheter angiography (CA), affected the yield of CA for the detection of acute LGIB. MATERIALS AND METHODS: TTP and LT were retrospectively evaluated in 120 patients who had positive findings for acute LGIB on (99m)Tc-labeled RBC scanning and subsequently underwent CA for the diagnosis and localization of gastrointestinal bleeding. Two nuclear medicine fellowship-trained radiologists independently reviewed the (99m)Tc-labeled RBC scans. Two fellowship-trained interventional radiologists independently reviewed the angiograms. All data were analyzed using SAS software. RESULTS: When a TTP threshold of ≤ 9 minutes was used, the sensitivity, specificity, positive predictive value, and negative predictive value for a positive CA study were 92%, 35%, 27%, and 94%, respectively. In addition, the odds of detecting bleeding on CA increased 6.1-fold with a TTP of ≤ 9 minutes relative to a TTP of > 9 minutes (p = 0.020). A significant inverse relationship was found between LT and a positive CA study (p = 0.041). CONCLUSION: TTP and LT impact the rate of positive CA studies. A TTP threshold of ≤ 9 minutes allows the detection of almost all patients who would benefit from CA for treatment and allows a reduction in unnecessary negative CA studies. The likelihood of positive findings on CA decreases with a delay in the performance of CA.

Basic neuroangiography: review of technique and perioperative patient care.

Neuroangiography (NA) is an important part of diagnosis and treatment of patients with neurological disease. Although NA may be performed for diagnostic purposes, in many instances NA is performed with the intent to treat. Indications for NA range from extracranial diseases (vertebrobasilar insufficiency from subclavian steal, extracranial carotid stenosis, cavernous-carotid fistula, neck trauma, epistaxis, tumor invasion of the carotid artery, and tumor embolization) to intracranial diseases (nontraumatic subarachnoid hemorrhage, cerebral aneurysms, cerebral arteriovenous malformations, cerebral vasospasm, acute stroke, tumor embolization, and WADA test). Similar to peripheral angiography, appropriate preprocedural assessment and postprocedural care, along with understanding of anatomy, catheter technique, and disease processes, are vital to successful outcomes. This article will review the basic technique, equipment, and patient management in NA. With appropriate skill and knowledge, interventional radiologists can perform NA with safe and successful results.

Transcatheter embolization in the management of epistaxis.

A majority of the population will experience epistaxis at some time in their life. Most cases will be from an anterior source and can be treated with pressure, anterior nasal packing, or cautery. Intractable epistaxis is generally posterior in origin and may require endoscopic cautery, posterior packing, surgical ligation, or embolization. Embolization has been used to treat epistaxis for more than 30 years and success can be achieved in approximately 90% of patients, with major complications occurring in approximately 2%. These excellent results require thorough knowledge of the regional anatomy, familiarity with the equipment and various agents used to achieve this type of embolization, as well as attention to detail and meticulous technique. There remains debate on several aspects of embolization, including the agent of choice, preferred size of the embolic, and the number of vessels to embolize. Advances in endoscopic surgery have evolved to the point that similar success rates for embolization and modern surgical techniques in treating epistaxis may be expected. This detailed review of pertinent vascular anatomy, embolization technique, and surgical alternatives should allow practitioners to formulate treatment algorithms that result in optimal outcomes at their institutions.

Contemporary endovascular embolotherapy for meningioma.

Preoperative endovascular tumor embolization has been used for 40 years. Meningiomas are the most common benign intracranial tumor in which preoperative embolization has been most extensively described in the literature. Advocates of embolization report that it reduces operative blood-loss, and softens the tumor, thus making surgery safer and easier. Opponents suggest that it adds additional risk and cost for patients without controlled studies showing conclusive benefit. The literature suggests a 3 to 6% neurological complication rate related to embolization. The combined external and internal carotid artery blood supply and complex anastomoses of the meninges can make embolization challenging. Positive outcomes require thorough knowledge of the pertinent vascular anatomy, familiarity with the neurovascular equipment and embolics, and meticulous technique. There remains debate on several aspects of embolization, including tumors most appropriate for embolization, embolic agent of choice, ideal size of embolic, and the choice of vessel(s) to embolize. This detailed review of pertinent vascular anatomy, embolization technique, results, and complications should allow practitioners to maximize treatment outcomes in this setting.

Carotid artery stenting: review of technique and update of recent literature.

Stroke is the fourth leading cause of death and the number one cause of long-term disability in the United States. Carotid stenosis is an important cause of ischemic strokes, accounting for 20 to 25%. Previous studies have established carotid endarterectomy as standard of care of symptomatic patients with > 50% stenosis and asymptomatic patients with > 60% stenosis; recently, carotid artery stenting has emerged as an alternative treatment for carotid stenosis. Several studies have been published comparing carotid artery stenting with endarterectomy with mixed results. In this article, the authors discuss carotid artery stenting technique, the results from the most recent trials, and future directions.

Impact of laser fiber design on outcome of endovenous ablation of lower-extremity varicose veins: results from a single practice.

The design of laser fibers used for endovenous laser ablation (EVLA) in the management of lower-extremity varicose vein disease may affect treatment success. The purpose of this investigation is to report our experience using the gold-tip NeverTouch VenaCure laser fiber (AngioDynamics, Queensbury, NY) and to compare that to our experience with standard bare-tip fibers. A retrospective chart review of 363 consecutive EVLA treatments using the gold-tip laser fiber was performed. Demographic data including patient age, sex, history of previous varicose vein stripping, vein identity, laterality, treatment length, total applied energy in joules (J), use of adjuvant sclerotherapy and ambulatory phlebectomy, treatment-related complications, and treatment failure, which was defined as recanalization of any portion of the treated vein during follow-up as assessed by duplex ultrasound examination-were entered into a spreadsheet. These data were compared with a control group of 471 EVLA treatments performed with a standard bare-tip laser fiber. Data were analyzed using independent-samples Student's t test, chi-square test, and multivariate analysis. Demographic data were similar between the two groups. Treatments with the gold-tip fiber had a failure rate of 11.1%, whereas treatment with a bare-tip fiber had a failure rate of 2.3% during a similar follow-up period. This difference was highly statistically significant (p<0.0001). Multivariate analysis showed fiber type as the most significant factor associated with treatment failure. We conclude that laser fiber design has a significant effect on treatment success in the performance of EVLA.

Acute deep vein thrombosis (DVT): evolving treatment strategies and endovascular therapy.

DVT and PE contribute to at least 100,000 deaths each year. In addition, 4% of patients with PE will progress to CTEPH and PTS will affect nearly 30%. Anticoagulation alone appears inadequate to prevent PTS in many patients. Newer treatment strategies, including PCDT, appear to offer the possibility of reducing the pain, suffering and expense of PTS especially in the most severe cases. The NIH/NHLBI sponsored the ATTRACT trial, which will compare PCDT plus standard anticoagulation versus standard anticoagulation alone in patients with proximal DVT. The ATTRACT trial will enroll patients at both Miriam and RI Hospitals and is expected to add significantly to the research in this area. When successfully completed, results from the trial may guide therapy in the years ahead.

An investigation of the relationship between energy density and endovenous laser ablation success: does energy density matter?

PURPOSE: To assess the relationship between energy density and the success of endovenous laser ablation (EVLA) treatment. MATERIALS AND METHODS: A total of 586 EVLAs were performed in a period of 35 months. Retrospective chart review was performed, and data collected included the patients' age, sex, and history of venous stripping procedures, as well as the name, laterality, and length of the treated vein segment(s) and the total energy delivered. Energy density was calculated by dividing total energy delivered (in J) by the length of vein (in cm). Energy density selection was based on the treating interventionalist's preference. Ablated segments were grouped into those treated with less than 60 J/cm, 60-80 J/cm, 81-100 J/cm, and more than 100 J/cm. Failure of EVLA was defined by recanalization of any portion of the treated vein during follow-up as assessed by duplex Doppler ultrasound examination. Failure rates were compared with the chi(2) test and Wilcoxon rank-sum test. RESULTS: A total of 471 segments were included in the analysis with an average follow-up period of 5 months (range, 0.2-28.7 months). Overall, 11 failures were encountered, including four in the group treated with less than 60 J/cm (n = 109; 4%), two in the 60-80-J/cm group (n = 77; 3%), four in the 81-100-J/cm group (n = 169; 3%), and one in the group treated with more than 100 J/cm (n = 116; 1%). There was no statistically significant difference in failure rates among energy density ranges. CONCLUSION: EVLA has a low failure rate that is not affected by energy density.

Regional infusion-radioembolization.

Selective internal radiation therapy involves the intra-arterial delivery of radioactive beads to the tumor while minimizing dosing to the adjacent organ. Because this technique invariably results in some degree of embolization, it has also been termed radioembolization. More than 8000 patients have been treated worldwide, with a large body of experience with primary hepatocellular carcinoma (HCC) and metastatic colorectal carcinoma (MCRC) and growing experience with other tumors (metastatic neuroendocrine, breast carcinoma, cholangiocarcinoma). Response rates by FDG-PET are 80% to 90%. Complications are uncommon and most often consist of self-limited malaise. More significant complications, including radiation-induced liver disease, ischemic cholecystitis, and gastrointestinal ulceration may be seen in up to 10% of patients. This underscores the critical importance of patient selection and meticulous technique. Median survival times in patients who have HCC and MCRC are significantly improved compared with historic controls. Further study is required to determine the appropriate role of radioembolization in the context of state-of-the-art chemotherapy and other liver-directed therapies.

The role of percutaneous revascularization for renal artery stenosis.

Renal artery stenosis (RAS) is usually caused by atherosclerosis or fibromuscular dysplasia. RAS leads to activation of the renin-angiotensin-aldosterone system and may result in hypertension, ischemic nephropathy, left ventricular hypertrophy and congestive heart failure. Management options include medical therapy and revascularization procedures. Recent studies have shown angiotensin receptor blockers (ARB) and angiotensin converting enzyme inhibitors (ACE-I) to be highly effective in treating the hypertension associated with RAS and in reducing cardiovascular events; however, they do not correct the underlying RAS and loss of renal mass may continue. Renal artery angioplasty was first performed by Gruntzig in 1978. The routine use of stents has increased technical success rates compared with angioplasty, and surgery is now only rarely performed. Although numerous case series claimed benefit in terms of blood pressure control, no adequately powered randomized, controlled, prospective study of renal artery interventions has reported their effect on cardiovascular morbidity or mortality. The CORAL trial, an ongoing study of renal artery stent placement and optimal medical therapy (OMT) funded by the National Institutes of Health, is the first study to attempt to do so. Until the CORAL trial results are in, physicians will continue to be faced with difficult choices when determining the optimal management for RAS patients and deciding which, if any, patients should be offered revascularization.

Evaluation and management of patients with peripheral artery disease by interventional radiologists: current practices.

PURPOSE: Traditionally, surgeons have served as primary consultants for patients with peripheral vascular disease for whom revascularization is considered. An important component of care for patients with peripheral artery disease (PAD) is risk factor management. The present study was undertaken to determine current management practices of interventional radiologists for patients with PAD and compare them to published data for vascular surgeons. If PAD patient management practices are similar, this would support direct referral of PAD patients who are considered for revascularization from primary care doctors to interventional radiologists. MATERIALS AND METHODS: An online survey was administered to full members of the Society of Interventional Radiology with e-mail addresses on file. Filtering was done to examine and compare interactions among several responses. The margin of error for the survey was +/-2%, based on 95% CIs for the entire surveyed population (N=2,371). RESULTS: Seventy-five percent of respondents see PAD patients in ambulatory office settings. Only eight percent see themselves as the physician responsible for risk factor management, similar to reported results of vascular surgeons (10%). Other variables examined, such as frequency of inquiring about Framingham risk factors, indicate similar practices to those previously reported for vascular surgeons. CONCLUSIONS: For interventional radiologists who accept direct referrals for medical management of patients with PAD, disease management by interventional radiologists is similar to that previously reported for vascular surgeons. This supports the role of interventional radiologists who accept direct referrals of patients with PAD as primary consultants to primary care doctors.

Distal embolic protection for renal arterial interventions.

Distal or embolic protection has intuitive appeal for its potential to prevent embolization of materials generated during interventional procedures. Distal protection devices (DPDs) have been most widely used in the coronary and carotid vascular beds, where they have demonstrated the ability to trap embolic materials and, in some cases, to reduce complications. Given the frequency of chronic kidney disease in patients with renal artery stenosis undergoing stent placement, it is reasonable to propose that these devices may play an important role in limiting distal embolization in the renal vasculature. Careful review of the literature reveals that atheroembolization does occur during renal arterial interventions, although it often goes undetected. Early experience with DPDs in the renal arteries in patients with suitable anatomy suggests retrieval of embolic materials in approximately 71% of cases and renal functional improvement/stabilization in 98% of cases. The combination of platelet inhibition and a DPD may provide even greater benefit. Given the critical importance of renal functional preservation, it follows that everything that can be done to prevent atheroembolism should be undertaken including the use of DPDs when anatomically feasible. The data available at this time support a beneficial role for these devices.

Uterine artery embolization for control of life-threatening hemorrhage at menarche: brief report.

Uncontrolled acute menorrhagia resulting in hemodynamic instability in the adolescent is uncommon. We report a case of life-threatening menorrhagia upon first menses in a 12-year-old girl who was successfully treated with uterine artery embolization after failure of standard gynecologic and medical measures. Testing eventually revealed a coagulopathy that resulted from decreased plasminogen activator inhibitor-1 activity in combination with an immature hypothalamic-pituitary-ovarian axis. Coagulation disorders are more common in patients presenting with severe menorrhagia upon menarche. Interventional radiologists should be aware of such coagulation abnormalities and the differences between adults and adolescents when contemplating uterine artery embolization for adolescent patients.

Interventional management of arc of buhler aneurysm.

The Arc of Buhler (AOB) represents a persistence of the ventral anastomosis between the superior mesenteric artery (SMA) and the celiac arterial systems. The exact incidence of the AOB is not known, but it is believed to be ≤ 4%. Aneurysms of this rare anomaly are even more uncommon. We report a case of an aneurysm of the AOB with an intact pancreaticoduodenal artery arcade (PDAA) and near occlusive celiac origin stenosis. Stenoses or occlusions of the celiac origin have been reported in association with AOB aneurysms, as well as in patients with PDAA aneurysms. Transcatheter embolization (TCE) was successfully performed, thereby excluding the AOB aneurysm while preserving flow through the PDAA. To our knowledge, this is the first report of successful percutaneous treatment of an AOB aneurysm. The pathophysiology and management AOB and PDAA aneurysms are reviewed. Review of the literature suggests that TCE, when feasible, is at least as effective as conventional surgery in patients with PDAA aneurysms, but with lower morbidity and mortality. Based on this data and our experience, we believe that TCE should be the initial treatment of choice in patients with PDAA or AOB aneurysms.

Acute Pericardial Effusion during Endovascular Intervention for Superior Vena Cava Syndrome: Case Series and Review.

We describe three cases of acute pericardial effusion during endovascular treatment of superior vena cava (SVC) syndrome, one of which resulted in fatal pericardial tamponade. SVC syndrome results from impaired venous return from the head and upper extremities to the right atrium. Malignancy and catheter-induced SVC stenosis accounts for the majority of cases of SVC syndrome. Endovascular therapy is the treatment of choice for SVC syndrome due to its rapid relief of symptoms and low morbidity. Acute pericardial effusion and pericardial tamponade may result from inadvertent extraluminal traversal of the SVC in the so-called danger zone above the right atrium, as well as secondary to dissection of wires in a location where fascial planes have been altered by neoplasia or inflammation.

Interventional management of renal vascular origin hematuria.

Several renal vascular pathological processes have been associated with hematuria. These include renal artery aneurysm (RAA), fibromuscular dysplasia (FMD), renal nutcracker syndrome (RNS), renal arteriovenous malformation, renal vasculitis, and renal artery or vein thrombosis. We present an unusual case of hematuria in a patient eventually diagnosed with RAA, FMD, and RNS. Percutaneous therapy, including endovascular coiling, percutaneous transluminal angioplasty, and stent placement were used to address the underlying pathology. The differential diagnosis, pathophysiology, and surgical and interventional management of these renal vascular disorders are reviewed.