Deepak Sudheendra

Retrieval of Tip-embedded Inferior Vena Cava Filters by Using the Endobronchial Forceps Technique: Experience at a Single Institution

PURPOSE To evaluate the use of endobronchial forceps to retrieve tip-embedded inferior vena cava (IVC) filters. MATERIALS AND METHODS This institutional review board-approved, HIPAA-compliant retrospective study included 114 patients who presented with tip-embedded IVC filters for removal from January 2005 to April 2014. The included patients consisted of 77 women and 37 men with a mean age of 43 years (range, 18-79 years). Filters were identified as tip embedded by using rotational venography. Rigid bronchoscopy forceps were used to dissect the tip or hook of the filter from the wall of the IVC. The filter was then removed through the sheath by using the endobronchial forceps. Statistical analysis entailed calculating percentages, ranges, and means. RESULTS The endobronchial forceps technique was used to successfully retrieve 109 of 114 (96%) tip-embedded IVC filters on an intention-to-treat basis. Five failures occurred in four patients in whom the technique was attempted but failed and one patient in whom retrieval was not attempted. Filters were in place for a mean of 465 days (range, 31-2976 days). The filters in this study included 10 Recovery, 33 G2, eight G2X, 11 Eclipse, one OptEase, six Option, 13 Günther Tulip, one ALN, and 31 Celect filters. Three minor complications and one major complication occurred, with no permanent sequelae. CONCLUSION The endobronchial forceps technique can be safely used to remove tip-embedded IVC filters.

Appropriate Premedication Risk Reduction During Adrenal Ablation

Editor: We read with great interest Atwell et al (1) report in the March issue of JVIR on “Malignant hypertension during cryoablation of an adrenal gland tumor.” We cannot stress enough the importance of effective collaboration between the interventional radiologist and anesthesia team. During manipulation of the adrenal gland by surgery or minimally invasive modalities, a hypertensive crisis due to systemic catecholamine release is a rare although not unheard of complication (1–4). When catecholamine release is thought to be likely (ie, functional adrenal tumor or pheochromocytoma), premedication with alpha adrenergic blockade such as phenoxybenzamine for several days prior to the procedure is critical in preventing hypertensive crisis. In these riskier settings, many patients may also require beta blockade due to the resultant tachycardia associated with alpha blockade, and thus the clinician should ensure that the patient receives beta blockade only after adequate alpha blockade. This is due to the fact that unopposed alpha receptor stimulation can also precipitate a hypertensive crisis (6). Furthermore, α-methyl-para-tyrosine or metyrosine (Demser™; Merck, Sharp & Dohme, West Point, PA) should be considered several weeks before the procedure. Metyrosine is a tyrosine hydroxylase inhibitor that blocks the conversion of tyrosine to DOPA, the rate-limiting step in the production of catecholamines, and subsequently reduces catecholamine production by 50 to 80% (7). Studies during surgery for pheochromocytoma have shown that a combination regimen of phenoxybenzamine and metyrosine is more effective in controlling blood pressure and results in less need for use of antihypertensive medication or pressors than single-agent α-adrenergic blockade alone (4). Less blood loss and less intraoperative fluid replacement have also been seen with this combination regimen (5). Since these findings have not been confirmed by any prospective study, it should be noted that the addition of metyrosine may not be suitable for every patient and should be considered on a case by case basis since preloading and dose titration of metyrosine may take weeks (7). The report by Atwell et al and other groups (1–3) on malignant hypertension in patients presumed to have nonfunctional tumors suggests that perhaps more patients with these tumors should be premedicated prior to surgery or ablation. While completely eliminating the possibility of a hypertensive crisis is unlikely, proper precautions could significantly decrease such events from occurring.

Intermittent hepatic vein balloon occlusion during radiofrequency ablation in the liver.

The purpose of the study was to assess the feasibility of intermittent hepatic vein balloon occlusion during percutaneous radiofrequency (RF) ablation. Eight non-anticoagulated patients who had primary (n = 2) and metastatic (n = 6) liver tumors with a mean diameter of 4.2 cm (range 2.4–6.5 cm) were treated, resulting in a mean ablation diameter of 6.3 cm (range 4.3–9.3 cm). Six of 9 (67%) of the balloon-occluded hepatic veins were patent. No clinical sequelae of thrombosis were noted. Mean length of follow-up with CT and/or MRI was 12 months. Local tumor control was achieved in 5 of 8 patients. Intermittent hepatic vein balloon occlusion could potentially be a low-risk adjunctive maneuver for thermal ablation therapy in the treatment of large tumors and tumors adjacent to large vessels.

Comparison of Three Different Needles for Percutaneous Injections

Several percutaneous local ablative therapies have been used to treat unresectable malignancies including percutaneous ethanol injection therapy (PEIT), acetic acid, hyperthermic saline and distilled water, gene therapy, liposomal or micelle vectors, and chemotherapeutic agents such as cisplatin. However, mechanical methods for injection of therapeutics remain primitive. Treatments must be able to distribute a small volume of therapeutic agent evenly and widely throughout the tumor, including the tumor margin, without tracking along fascial planes and killing healthy tissue. Because percutaneous injection therapy relies on the ability to accurately distribute the therapeutic agent within the tumor, the orientation of the needle and needle holes may be an important factor. Two different types of needles are commonly used in percutaneous injection procedures: single end-hole needles and needles with a closed conical tip and three terminal side-holes (Fig. 1A). Alternatively, a three-pronged array needle with variable intra-prong distances (Fig. 1B) has recently become available (Quadra-Fuse, Rex Medical, Radnor, PA, USA). The injection distributions of these three injection systems were compared. Fig. 1 a–c. Diffusion of contrast agent by single end-hole, three side-hole, and array needles. a Three side-hole needle. b Array needle. c Coronal CT scan of cow liver showing distribution of contrast agent by type of needle. For this purpose, an experiment was performed on a 7.71 kg cow liver comparing three distinct types of injection needles: an 18G, 15 cm DISP Chiba Biopsy needle with a single end-hole (Cook, Bloomington, IN, USA); a 22G, 15 cm Bernadino three side-hole infusion needle (Cook, Bloomington, IN, USA); and an 18G Rex Medical Quadra-Fuse three-pronged array injection needle (Rex Medical, Radnor, PA, USA). Each needle type (single end-hole, three side-hole, and array) was used to inject two different contrast solutions (5 cm3). All six injections were in the same plane to ensure visualization in one computed tomography (CT) slice (Fig. 1C). The two different contrast solutions used to visualize injection were 10% Hypaque-Cysto (diatrizoate meg-lumine) in normal saline, and 10% ethiodol (37% iodine) in Johnson’s Baby Oil (Johnson & Johnson, Skillman, NJ, USA). For the single end-hole and three side-hole needles, contrast solution was injected beginning at 3 cm with the tips slowly raised in approximately 2 mm increments with 0.5 cm3 injections until 4 cm3 had been injected. The needles were then lowered to the initial 3 cm depth and the remaining 1 cm3 was injected. The array needle was inserted 3 cm into the liver and deployed 1 cm. Then 0.5 cm3 of contrast solution was injected. The array was retracted, the needle rotated 60° and redeployed to 1 cm followed by another 0.5 cm3 injection. This method was repeated with deployment increments of 1 cm until the entire 5 cm3 volume was injected (5 cm maximum deployment). A detailed image analysis of the solutions’ trajectories within the cow liver was done with a helical CT scanner (General Electric, 120 kV, 100 mA, 0.625 mm slice thickness, 0.625 cycles per second). The three side-hole needle provided improved echogenicity and linear tracking compared with standard biopsy needles. Using equivalent injection volumes, the three side-hole needle produced greater zones of chemical dispersion for both the saline and oil contrast agents when compared with the single side-hole needle. Both the single-side-hole and the three side-hole needles produced confined distributions. A study by Geschwind et al. compared necrosis diameters and volumes after PEIT using a single side-hole needle and the three-pronged array needle. After injection of identical volumes of ethanol, the three-pronged array needle achieved larger necrosis volumes and diameters [1]. Contrast injection was better distributed and dispersed over a broader volume with the array needle (Fig. 1B) compared with the same contrast volume with the other needles. Both the single end-hole needle and to a lesser extent the three side-hole needle (Fig. 1A) produced poorly controlled injection distributions. These distributions appeared to be elongated in the anterior-posterior plane parallel to the direction of the needle, presumably along blood vessels and fascial planes. The array needle produced a star-shaped distribution visualized regularly in coronal slices (Fig. 1C). After allowing sufficient time for diffusion, a spherical zone of contrast agent was visualized around the array, while the distributions around the single end-hole and three side-hole needles were elongated and less uniform. Although measurements were done retrospectively in the x-axis using one CT image, the array needle had a 5.0 cm zone of distribution with both oil and saline. The single end-hole needle had a 2.0 and 2.5 cm zone of distribution for oil and saline respectively. The triple side-hole needle had a zone of distribution of 2.0 and 1.0 cm for oil and saline, respectively. While these findings are intriguing, there are several limitations to this study. Because the experiment was performed ex vivo, the lack of perfusion may have limited the distribution of contrast solution. However, this limitation is likely to affect all three needles similarly. Because the liver specimen was not uniform and injections were performed only once with each contrast solution, variable orientations of fascial planes and vasculature might have affected the distributions of each needle unequally. Confirming these distribution patterns in vivo and correlating these observations with the imaging and histologic findings might verify our findings. Moreover, depending on the disease process affecting the liver (i.e., primary hepatocellular carcinoma versus metastatic liver disease versus cholangiocarcinoma), diffusion of contrast agents may differ and subsequently CT imaging of contrast distribution may not correlate with cell destruction. While these limitations preclude a quantitative analysis of volume distributions within the liver specimen, the qualitative results obtained from CT are still interesting. Qualitative visualization of injection distributions suggests that the array needle might produce more spherical distributions which would presumably lead to more predictable zones of treatment. The array needle is currently our needle of choice for injectable therapeutics and is being used to inject gene therapy in a clinical trial. More uniform distribution of injected anticancer agents could improve efficacy of current percutaneous therapies.

Effect of Central Venous Angioplasty on Hemodialysis Access Circuit Flow: Prospective Study of 25 Symptomatic Patients

PURPOSE To quantify the effect of central venous percutaneous transluminal angioplasty (PTA) on blood flow within hemodialysis access circuits in patients with symptomatic central venous stenosis (CVS). MATERIALS AND METHODS This prospective study enrolled 30 adults with symptoms attributable to CVS ipsilateral to their access. Five subjects were deregistered because of a lack of CVS (n = 1), untreatable lesion (n = 1), or improper flow measurement timing (n = 3); 25 completed the study (15 men and 10 women; mean age, 62 y; age range, 33-87 y). There were 7 fistulae, 15 grafts, and 3 hybrid access circuits. Mean access age was 675 days (range, 16-3,039 d). Mean CVS symptom duration was 37 days (range, 3-120 d). Peripheral stenoses, if present, were treated first. Intraaccess flow was measured immediately before and immediately after CVS treatment (PTA, stent). RESULTS Eleven patients had only CVS, whereas 14 had at least 1 peripheral lesion in addition to CVS. All stenoses underwent PTA. Mean flow rates were 1,424 mL/min (range, 565-2,765 mL/min) before PTA and 1,535 mL/min (range, 598-2,545 mL/min) afterward, yielding a mean increase of 111 mL/min ± 456 or 15% ± 34 (range, -70% to +100%; 95% confidence interval, 1%-29%). Flow was decreased in 9 patients (36%). CVS symptoms were reduced in 24 patients (96%) and recurred in 14 (58%) within a mean of 110 days (range, 7-459 d) after initial PTA. Mean follow-up was 371 days (range, 17-592 d). CONCLUSIONS CVS symptoms were observed to occur over a wide range of blood flow rates. On average, central venous PTA only mildly increased flow yet reduced symptoms regardless of flow change.

Radiologic Techniques and Effectiveness of Angiography to Diagnose and Treat Acute Upper Gastrointestinal Bleeding

The use of catheter-based techniques to treat upper gastrointestinal hemorrhage has evolved considerably over the past few decades. At present, the state-of-the-art interventional suites provide optimal imaging. Coupled with advanced catheter technology, the two may be used to manage and treat the patient with acute upper gastrointestinal hemorrhage. This article summarizes these techniques and, when possible, compares them with other methods such as surgery and endoscopy. The specific role of transcatheter embolotherapy is highlighted, alongside an additional discussion on pharmacologic infusion of vasopressin.

Effect of Substituting 50% Isovue for Sterile Water as the Delivery Medium for SIR-Spheres: Improved Dose Delivery and Decreased Incidence of Stasis.

Purpose The objective of this study was to evaluate the effect of substituting 50% Isovue (Bracco Diagnostics Inc, Monroe Township, NJ) for sterile water on the delivery of 90Y resin microspheres (SIR-Spheres [Sirtex Medical Limited, Sydney, Australia]). Materials and Methods The authors retrospectively reviewed all SIR-Spheres radioembolizations at the authors’ institution from January 1, 2011, to February 10, 2014. From January 1, 2011, to April 30, 2013, all users performed SIR-Spheres radioembolization per the manufacturer’s original instructions using sterile water in the B and D lines and intermittently checking the progress of the embolization by injecting contrast via the B line. Beginning May 1, 2013, a modified technique using Isovue diluted 50% with saline in place of sterile water in both the B and D lines of the infusion set. The authors compared the prepared versus administered activity of 90Y SIR-Spheres, fluoroscopy time, administration time, and frequency of radioembolizations terminated for stasis when using water versus dilute contrast in the B and D lines. Results One hundred seventy-five radioembolizations were performed, 132 (75%) with water as the delivery medium and 43 (25%) with 50% contrast as delivery medium. The mean percentage of the 90Y activity administered was 98% with contrast versus 87% with water (P < 0.01). More than 95% of cases using contrast resulted in 90% or more delivery of the prepared 90Y activity versus 59% of cases with water (P < 0.01). For cases using water, 17% were terminated for stasis, whereas 2% (1 case) using contrast was terminated for stasis. The mean 90Y administration time was 7 minutes with contrast versus 22 minutes with water (P = 0.015). Excluding the 37 cases involving coil embolization, the mean fluoroscopy time was 8.3 minutes with contrast versus 11.5 minutes with water (P < 0.05). No complications occurred with the contrast method; however, there were 4 complications with water, including 1 nontarget gastric ulceration. Conclusions Using dilute contrast as the delivery medium for SIR-Spheres resulted in a significantly greater percentage of the prepared activity administered to the patient with substantially shorter administration time. Termination for stasis occurred less often with dilute contrast. No complications were observed when using dilute contrast, which allowed continuous real-time monitoring of the 90Y microsphere administration.

Role of Catheter-directed Thrombolysis in Management of Iliofemoral Deep Venous Thrombosis

The treatment for iliofemoral deep venous thrombosis (DVT) is challenging, as the use of anticoagulation alone can be insufficient for restoring venous patency and thus lead to prolongation of acute symptoms and an increased risk of chronic complications, including venous insufficiency and postthrombotic syndrome (PTS). In these cases, earlier and more complete thrombus removal can ameliorate acute symptoms and reduce long-term sequelae. Endovascular therapies involving the use of pharmacologic, mechanical, and combined pharmacomechanical modalities have been developed to achieve these goals. The most frequently used of these techniques, catheter-directed thrombolysis (CDT), involves the infusion of a thrombolytic agent through a multiple-side-hole catheter placed within the thrombosed vein to achieve high local doses and thereby break down the clot while minimizing systemic thrombolytic agent exposure. Randomized controlled trial results have indicated decreased PTS rates and improved venous patency rates in patients treated with CDT compared with these rates in patients treated with anticoagulation. The use of newer pharmacomechanical techniques, as compared with conventional CDT, reduces procedural times and thrombolytic agent doses and is the subject of ongoing investigations. Endovascular thrombus removal techniques offer a means to improve venous valvular function and decrease the risk of debilitating long-term complications such as PTS and are a promising option for treating patients with iliofemoral DVT. (©)RSNA, 2016.

Initial Clinical Experience: Symmetric-Tip Dialysis Catheter with Helical Flow Characteristics Improves Patient Outcomes

PURPOSE To report preliminary clinical experience with a new symmetric-tip dialysis catheter compared with a conventional split-tip catheter. MATERIALS AND METHODS Over a 5-month period, patients requiring a tunneled catheter for hemodialysis or undergoing exchange of a dysfunctional dialysis catheter at a tertiary academic medical center were retrospectively analyzed. Patients underwent placement of a VectorFlow or Ash Split Cath catheter at the discretion of the inserting interventional radiologist. Patient demographics, catheter patency, mean blood flow rate, and arterial and venous pressures were compared according to catheter type. Catheter failure was analyzed based on clinical and anatomic variables by using a multivariate Cox proportional-hazards model. RESULTS A total of 33 VectorFlow and 46 Ash Split Cath catheters were placed. Patients in the VectorFlow group had significantly higher body mass index (P = .013) and Charlson Comorbidity Index (P = .049), as well as more non-internal jugular vein placements. At 120 days, 89% of VectorFlow catheters remained functional, compared with 45% of Ash Split Cath catheters (P = .046). The VectorFlow catheter was associated with 16% lower arterial pressures during dialysis (P = .009); mean blood flow rate was equivalent. On multivariate analysis, the risk of catheter failure was 13.3 times higher in the Ash Split Cath group compared with the VectorFlow group (P = .004). Left-sided catheters were also predictive of catheter failure (relative risk = 5.5; P = .02). CONCLUSIONS The VectorFlow catheter was associated with a significant increase in intervention-free catheter patency compared with the Ash Split Cath catheter, with equivalent flow at lower arterial pressures during dialysis.

Catheter-Directed Therapy Options for Iliofemoral Venous Thrombosis

Proximal deep venous thrombosis (DVT) is linked to a 50% risk of pulmonary embolism and a 50% risk of postthrombotic syndrome. This article reviews catheter-directed thrombolysis options for iliofemoral DVT and discusses the risks, benefits, and techniques commonly used in performing endovascular procedures for iliofemoral DVT.