Robert G. Dixon

Guidelines for Patient Radiation Dose Management

Michael S. Stecker, MD, Stephen Balter, PhD, Richard B. Towbin, MD, Donald L. Miller, MD, Eliseo Vano, PhD,Gabriel Bartal, MD, J. Fritz Angle, MD, Christine P. Chao, MD, Alan M. Cohen, MD, Robert G. Dixon, MD,Kathleen Gross, MSN, RN-BC, CRN, George G. Hartnell, MD, Beth Schueler, PhD, John D. Statler, MD,Thierry de Baere, MD, and John F. Cardella, MD, for the SIR Safety and Health Committee and the CIRSEStandards of Practice Committee

Transcatheter Thrombolytic Therapy for Acute Mesenteric and Portal Vein Thrombosis

PURPOSE The purpose of this study was to evaluate the utility of transcatheter thrombolytic therapy in 20 patients with acute or subacute (symptoms <40 days) portal and/or mesenteric vein thrombosis with severe symptoms, deteriorating clinical condition, and/or persistent symptoms despite anticoagulation. MATERIALS AND METHODS This retrospective study examined 12 male patients and eight female patients seen over a period of 11 years. The average age was 37.6 years. Four of the patients had previously undergone liver transplantation. An anatomic classification system was established to describe the extent of thrombus at the time of diagnosis. Patients were treated with thrombolytic therapy via the transhepatic route, common femoral vein route, and/or superior mesenteric artery route. Improvement in symptoms, avoidance of bowel resection, complications, and radiographic evidence of clot resolution were the main clinical outcomes. RESULTS Fifteen of the 20 patients exhibited some degree of lysis of the thrombus. Three patients had complete resolution, 12 had partial resolution, and five had no resolution. Eighty-five percent of patients (n = 17) had resolution of symptoms. Sixty percent of patients (n = 12) developed a major complication. No patients required bowel resection after thrombolytic therapy. One patient died with gastrointestinal hemorrhage and septic shock 2 weeks after thrombolytic therapy. Other major complications included bleeding and conditions requiring transfusion. No patients developed new portal or mesenteric thromboses. Two of the patients who received transplants eventually required repeat transplantation. CONCLUSIONS Transcatheter thrombolysis was beneficial in avoiding patient death, resolving thrombus, improving symptoms, and avoiding bowel resection. However, there was a high complication rate, indicating that this therapy should be reserved for patients with severe disease. Further evaluation of these techniques and outcomes should continue to be pursued.

Embedded Inferior Vena Cava Filter Removal: Use of Endobronchial Forceps

PURPOSE Removing a retrievable inferior vena cava (IVC) filter can be extremely difficult with the use of standard techniques if the filter is tilted and embedded in the wall of the IVC. The use of rigid endobronchial forceps has been described in case reports to remove embedded IVC filters, and the present report describes the use of this technique to remove a series of tip-embedded IVC filters in two separate institutions. MATERIALS AND METHODS The medical records were reviewed of 21 consecutive patients at two institutions who underwent attempted IVC filter removal with rigid endobronchial forceps over a 34-month period. The mean age of patients was 32.4 years (range, 14.1-54.1 y). The patients had the following filters: Recovery (n = 6), G2 (n = 10), Günther Tulip (n = 4), and OptEase (n = 1). RESULTS Rotational or biplane venography was used to confirm that the filters were tilted and embedded in the wall of the IVC in all 21 patients. Rigid endobronchial forceps were used successfully to remove 20 embedded IVC filters in 21 patients. There was one case of failure to remove an embedded suprarenal G2 filter. There were no major complications. CONCLUSIONS Rigid endobronchial forceps may be used as a reliable option for removal of embedded IVC filters.

Quality Improvement Guidelines for Recording Patient Radiation Dose in the Medical Record for Fluoroscopically Guided Procedures

ACR American College of Radiology, CRCPD Conference of Radiation Control Program Directors, FDA Food and Drug Administration, ICRU International Commission on Radiation Units and Measurements, IEC International Electrotechnical Commission, IRP interventional reference point, Ka,r total air kerma at the interventional reference point, NCRP National Council on Radiation Protection and Measurements, PKA kerma–area product, PSD peak skin dose, RDSR Radiation Dose Structured Report

Long-term Retrieval Success Rate Profile for the Günther Tulip Vena Cava Filter

PURPOSE To evaluate the likelihood of successful retrieval of the Günther Tulip vena cava filter after various implant durations (up to 494 days). MATERIALS AND METHODS Retrievable Günther Tulip filters were placed in 554 patients. All patients satisfied requirements for filter placement; the primary indication for placement was specified for 394 patients (71%), as follows: unspecified trauma (n = 164), bariatric procedures (n = 128), orthopedic procedures (n = 36), and other (n = 66). Filter tilt and vena cava injury were assessed at implantation. Filters were not repositioned after placement. At retrieval, filter orientation, vena cava injury, other device-related incidents, and the degree of difficulty associated with retrieval were reported. RESULTS Filter retrieval was attempted in 275 patients and successful in 248 (90.2%). The mean filter indwell time was 58.9 days (range, 3-494 days). Unsuccessful retrievals (n = 27) were attributed primarily to improper hook orientation (n = 10) or excessive tissue in-growth at the filter legs (n = 16). Of the remaining 279 patients, 223 withdrew from the study, 41 were associated with a decision to keep the filter as a permanent device, 13 died for reasons unrelated to the study, and two had no reported endpoint data. A Kaplan-Meier product-limit survival estimate revealed that the probability of successful device retrieval remained greater than 94% at 12 weeks and greater than 67% at 26 weeks. CONCLUSIONS This study contributes to the body of clinical data related to retrievable filters, demonstrating reliable retrieval rates at 12 weeks, with successful retrievals up to 17 months after implantation.

Factors Associated with Failed Retrieval of the Günther Tulip Inferior Vena Cava Filter

PURPOSE To identify potential factors associated with failed retrieval of the Günther Tulip inferior vena cava (IVC) filter. MATERIALS AND METHODS A retrospective review was performed of patients who underwent placement of the Günther Tulip filter with at least one attempt at filter retrieval over a 3-year period. Patient demographics, filter dwell time, filter angulation, and filter leg protrusion were analyzed. RESULTS A total of 188 patients were included in the study. Primary retrieval success was achieved in 166 patients (88.3%), for an overall retrieval success rate of 94.2%. The overall mean dwell time was 63 days, whereas the mean dwell time in cases of retrieval failure was 95.4 days. A total of seven filters were in place for longer than 6 months, four of which were successfully retrieved. The degree of filter tilt was not found to be significantly related to retrieval success (P = .36), even though filter angulation was commonly cited as a reason for retrieval failure. On venography, 90.9% of filters that could not be retrieved showed leg protrusion beyond the lumen of the IVC. Finally, increasing patient age also correlated with retrieval failure (P = .01). CONCLUSIONS Prolonged dwell time and increasing patient age are associated with failed filter retrieval. However, even filters in place for extended periods can be safely removed.

Radiation management for interventions using fluoroscopic or computed tomographic guidance during pregnancy: A joint guideline of the Society of Interventional Radiology and the Cardiovascular and Interventional Radiological Society of Europe with endorsement by the Canadian Interventional Radiology Association

Lawrence T. Dauer, PhD, CHP, Raymond H. Thornton, MD, Donald L. Miller, MD, John Damilakis, PhD, Robert G. Dixon, MD, M. Victoria Marx, MD, Beth A. Schueler, PhD, Eliseo Vano, PhD, Aradhana Venkatesan, MD, Gabriel Bartal, MD, Dimitrios Tsetis, MD, PhD, and John F. Cardella, MD, for the Society of Interventional Radiology Safety and Health Committee and the Cardiovascular and Interventional Radiology Society of Europe Standards of Practice Committee

Transcatheter Arterial Embolization of Gastroduodenal Artery Stump Pseudoaneurysms after Pancreaticoduodenectomy: Safety and Efficacy of Two Embolization Techniques

PURPOSE To evaluate the safety and efficacy of two transcatheter arterial embolization (TAE) techniques used to treat pseudoaneurysms of the gastroduodenal artery (GDA) stump after pancreaticoduodenectomy. MATERIALS AND METHODS Between March 2003 and March 2008, 16 patients were treated with TAE for pseudoaneurysms of the GDA stump after pancreaticoduodenectomy. Two embolization techniques were employed: endovascular trapping of the hepatic artery (embolization of the hepatic artery proximal and distal to GDA stump; group A; n = 13) and selective embolization of the GDA stump and/or pseudoaneurysm sparing hepatic arterial flow (group B; n = 3). Technical success, initial hemostasis, recurrence of bleeding, and complications were compared between the two groups retrospectively. RESULTS All TAE procedures were technically successful and immediate hemostasis was achieved in all patients. There was no recurrent bleeding in group A; however, all three patients in group B experienced recurrent bleeding after initial hemostasis (P = .002), and these patients required subsequent embolization with the endovascular trapping technique. Two patients died of multiple organ failure (one patient in each group) despite successful hemostasis. Three patients experienced subsegmental (n = 1, group A) and multisegmental (n = 2, group B) liver infarction, which were successfully managed with conservative treatment. There was a higher incidence of major complications in group B (15.4% vs 100%; P = .018). CONCLUSIONS Endovascular trapping of the hepatic artery is a safe and effective treatment of pseudoaneurysms of the GDA stump after pancreaticoduodenectomy. Hepatic ischemic complications are not rare, but can be conservatively managed. Selective embolization of the GDA stump and/or pseudoaneurysm is frequently associated with recurrence of bleeding, which eventually leads to major complications.

Risk-group targeted inferior vena cava filter placement in gastric bypass patients.

BackgroundDespite a growing body of evidence guiding appropriate perioperative thromboprophylaxis in the general population, few data direct strategies to reduce deep venous thrombosis (DVT) and pulmonary embolism (PE) in the morbidly obese. We have implemented a novel protocol for venous thromboembolism (VTE) risk stratification in Roux-en-Y gastric bypass (RYGB) candidates at our institution, which augments clinical assessment with screening for thrombophilias, to guide retrievable inferior vena cava (IVC) filter utilization.MethodsA retrospective review of prospectively collected data from patients who underwent primary RYGB between 2001 and 2008 at the University of North Carolina at Chapel Hill was completed. During that time, clinical assessment of VTE risk was amplified by focused plasma screening for common thrombophilias (factors VIII, IX, and XI, d-dimer, fibrinogen). Preoperative prophylactic IVC filters were offered to high-risk patients. The database was reviewed for perioperative DVTs, PEs, and filter-related complications.ResultsOf 330 patients, in 162 attempts, 160 had prophylactic IVC filters placed with four complications overall (2.47%). No patient had symptoms of PE during the planned 6-week filter period, though one had a PE occur immediately after filter removal (0.63%); in contrast, five of 170 patients (2.94%) without prophylactic IVC filters presented with symptomatic PE (p = 0.216). In total, 147 (91.88%) prophylactic filters were removed.ConclusionsRisk-group targeted prophylactic inferior vena cava filter placement prior to RYGB is safe with a trend towards reduced occurrence of PE.

Radiation Protection in Interventional Radiology: Survey Results of Attitudes and Use

PURPOSE To assess attitudes of interventional radiologists toward personal radiation protection and the use of radiation protection devices. MATERIALS AND METHODS Invitations to an anonymous online survey that comprised eight questions focused on operator attitudes toward radiation protection devices were sent via e-mail to the active membership of the Society of Interventional Radiology (SIR): a total of 3,158 e-mail invitations. A single reminder e-mail was sent. RESULTS There were 504 survey responders (16% response rate). Reported radiation safety device use included lead apron (99%), thyroid shield (94%), leaded eyeglasses (54%), ceiling-suspended leaded shield (44%), rolling leaded shields (12%), ceiling-suspended/rolling lead-equivalent apron (4%), radiation-attenuating sterile surgical gloves (1%), and sterile lead-equivalent patient-mounted drape (4%). Reasons commonly cited for not using certain devices were comfort (eyewear), ease of use (mounted shields), and lack of availability (rolling/hanging shields and patient-mounted shields). CONCLUSIONS Interventionalists have an array of tools from which to choose for personal radiation protection; however, for a variety of reasons related to lack of availability or choice, these tools are not universally employed. Further study may be of value to clarify why comfort was cited most often as the primary barrier to the use of protective eyewear and difficulty of use was cited as the primary barrier to use of mounted shields (despite reporting that concern for radiation-induced injury to the eye is paramount). It may also be of interest to further study why certain devices with demonstrable protection effects are not readily available, such as rolling/hanging and patient-mounted shields.