Kong T. Tan

Radiofrequency In Situ Fenestration for Aortic Arch Vessels During Thoracic Endovascular Repair

Purpose: To report the first clinical application of a novel technique using radiofrequency puncture to create retrograde in situ fenestrations during thoracic endovascular aortic repair (TEVAR). Methods: Between June 2011 and December 2013, 40 TEVAR procedures were performed in our facility, including 10 cases in which in situ fenestration was planned. Two thoracic stent-graft models were deployed: the Valiant (n=5) and the Zenith TX2 (n=5). A 0.035-inch PowerWire radiofrequency guidewire delivered from a brachial approach was used to fenestrate the grafts covering a left subclavian artery (LSA) in 9 cases and a left common carotid artery in one. The fenestrations were serially dilated to 6 mm, and self-expanding Advanta V12 covered stents were positioned in the target arteries. Results: Technical success was achieved in 6 of the 10 planned cases. Of the remaining 4 cases, stent-grafts were deployed in zone 3 in 2 cases (one received a chimney to the LSA). Another stent-graft was deployed in zone 2 without endoleak after fenestration was abandoned (the LSA had good filling via the vertebral artery). In the last case, the fenestration was unsuccessful in double-layered (proximal extension overlap) stent-grafts; a carotid-axillary bypass was required. There were no fenestration-related complications, but overall surgical complications included a case of paraparesis that resolved following spinal drainage and a death from a preexisting aortoesophageal fistula. There were no postoperative strokes. All fenestrations remained patent, and there were no endoleaks at a mean 12-month follow-up (range 1–33). Conclusion: Radiofrequency puncture is a viable alternative to needle or laser punctures for in situ fenestration during TEVAR. Early clinical results suggest technical feasibility and acceptable early outcomes.

Pain after Percutaneous Liver Biopsy for Diffuse Hepatic Disease: A Randomized Trial Comparing Subcostal and Intercostal Approaches

PURPOSE To compare pain levels as measured by visual analog scale (VAS) and analgesic requirement between intercostal and anterior subcostal ultrasound (US)-guided biopsy. MATERIALS AND METHODS Seventy consecutive patients were randomized to undergo biopsy via an intercostal (n = 33) or subcostal (n = 37) approach. The groups were matched with regard to baseline characteristics: mean age, 44 years; age range, 20-70 years; sex, 43 male and 27 female; and indications of hepatitis C in 69%, hepatitis B in 16%, and others in 15%. The VAS score was obtained immediately after biopsy and hourly for 4 hours until the patients were discharged. Analgesic requirements and postprocedural complications were documented. RESULTS No significant difference in VAS scores was seen between the groups. At hours 0, 1, 2, 3, and 4, the VAS scores (on a scale of 100) in the intercostal and subcostal groups were 10.3 +/- 16.7 versus 11.8 +/- 16.0 (P = .70), 19.1 +/- 24.0 versus 13.9 +/- 16.2 (P = .30), 11.5 +/- 14.8 versus 11.8 +/- 15.1 (P = .93), 6.2 +/- 8.9 versus 7.5 +/- 11.5 (P = .63), and 5.4 +/- 8.2 versus 4.7 +/- 8.5 (P = .72), respectively. The average VAS was less than 10. In the intercostal biopsy group, 36.4% of patients required additional analgesia after biopsy, compared with 27.0% in the subcostal biopsy group (P = .64). One patient in the intercostal group refused to have future follow-up biopsy even if it was clinically indicated, compared with no such patients in the subcostal biopsy group. No differences in diagnostic samples or major complications were seen in either group. CONCLUSION US-guided percutaneous liver biopsy performed with fentanyl and midazolam premedication is a well-tolerated procedure with minimal patient discomfort. The location of the biopsy does not influence the outcome of the procedure.

Venous aneurysms in autogenous hemodialysis fistulas: is there an association with venous outflow stenosis.

Purpose To determine whether patients with venous aneurysms in their arteriovenous fistulas (AVFs) have associated venous outflow stenoses. Materials and Methods A retrospective study was performed, which included all patients presenting with dysfunction and had venous aneurysms in their AVFs. Patients medical records and imaging studies were examined and data collected including access characteristics, patient demographics and imaging findings. Data were analyzed using Fishers exact test. Results A total of 89 patients (58 men, 31 women; mean age 60) presented for intervention related to access dysfunction with incident venous aneurysms over the study period. Of the 89 patients with venous aneurysms (mean diameter 2.3 cm) of their AVFs, 69 (78%) patients had an associated venous outflow stenosis. The stenoses were present most commonly in the outflow cephalic vein (57%), followed by the cephalic arch (20%), brachiocephalic vein (10%) and subclavian vein (6%). Outflow stenoses in AVFs with venous aneurysms were observed in 87% of brachiocephalic AVFs, 60% of radiocephalic AVFs and 80% of brachiobasilic AVFs. Brachiocephalic AVFs with venous aneurysms were significantly more likely to have an associated outflow stenosis than radiocephalic AVFs with venous aneurysms (P=0.007). AVFs with outflow stenosis were on average 1502 days old while AVFs without outflow stenosis were on average 2351 days old, which was a statistically significant difference (P=0.031). No statistically significant differences were observed for sex and side of the fistula. Conclusions Outflow stenosis was observed to be associated with venous aneurysms in AVFs with a more statistically significant association in brachiocephalic AVFs compared to other AVFs.

Use of Expanded Polytetrafluoroethylene–covered Nitinol Stents for the Salvage of Dysfunctional Autogenous Hemodialysis Fistulas

The use of expanded polytetrafluoroethylene (ePTFE)-covered nitinol stents for salvage of hemodialysis fistulas was retrospectively examined. Seven covered stents were placed in five patients with failing fistulas considered unsalvageable. Indications included recurrent stenoses, thrombosis, and pseudoaneurysm formation. Before intervention, all patients required multiple interventions. The technical success rate was 100%. The primary patency rate was 80%, with secondary patency and lesion patency rates of 100% at 9 months. The incidence of follow-up repeat intervention was 0.3 per year. There were no complications. The use of ePTFE-covered stent placement in dysfunctional autogenous fistulas is technically feasible and, in this small series, was effective in preserving function and preventing access abandonment.

Randomized Trial Comparing Radiologic Pigtail Gastrostomy and Peroral Image-Guided Gastrostomy: Intra- and Postprocedural Pain, Radiation Exposure, Complications, and Quality of Life

PURPOSE To prospectively compare radiologically created pigtail gastrostomy (PG), in which the tube is inserted directly through the abdominal wall, versus peroral image-guided gastrostomy (POG), in which the tube is inserted through the mouth. Pain profiles (primary outcome measure), fluoroscopy times, total room times, technical success, complications, and quality of life (QOL) were measured. MATERIALS AND METHODS Sixty patients were prospectively randomized to receive 14-F PG or 20-F POG tubes. All patients received prophylactically created gastrostomies before radiation therapy for head and neck squamous-cell carcinoma. Patients receiving palliative treatment were excluded, as were those with established pharyngeal obstruction. Pain was measured by numeric rating scale (NRS) scores for 6 weeks after the procedure and by intraprocedural fentanyl and midazolam doses and postprocedural 24-h morphine doses. Fluoroscopy times, total room times, technical success, complications up to 6 months, and gastrostomy-related QOL (using the Functional Assessment of Cancer Therapy-Enteral Feeding questionnaire) were determined. RESULTS Fifty-six patients underwent the randomized procedure. The POG group required significantly higher intraprocedural midazolam and fentanyl doses (mean, 1.2 mg and 67 μg, respectively, for PG vs 1.9 mg and 105 μg for POG; P < .001) and had significantly longer fluoroscopy times (mean, 1.3 min for PG vs 4.8 min for POG; P < .0001). NRS scores, morphine doses, total room times, technical success, complication rates, and QOL did not differ significantly between groups. The one major complication, a misplaced PG in the peritoneal cavity, followed a technical failure of POG creation. CONCLUSIONS Despite the differences in insertion technique and tube caliber, the measured outcomes of POG and PG are comparable.

Direct sac puncture versus transarterial embolization of type II endoleaks: An evaluation and comparison of outcomes.

Purpose To determine the outcomes of type II endoleak embolization with aneurysm sac obliteration and whether the approach – direct sac puncture or transarterial – affects outcome. Methods A retrospective review of patients who underwent endovascular aneurysm repairs and subsequent type II endoleak embolization over 10 years was performed. Twenty-three patients (median age: 73 years, range: 40–88 years) underwent 35 embolizations. Embolization was performed with the goal of obliterating both the endoleak sac and feeding vessels. Embolization agents used include cyanoacrylate glue only (48%), glue and coils (36%), coils only (13%), and other (3%). Results Mean follow-up was 21.8 months. Patients underwent an average of 1.5 embolizations, with 35% requiring more than one. Technical success rate was 89%. Freedom from aneurysm sac expansion was achieved in 91%. Freedom from type II endoleak was accomplished in 70%. There were no ruptured aneurysms during the follow-up period. Direct sac puncture and transarterial approaches had similar incidences of aneurysm sac growth (p = 0.74), persistent type II endoleak (p = 0.32), and complications (p = 0.64). However, direct sac puncture had significantly shorter fluoroscopy (p < 0.001) and total procedure times (p < 0.001) than transarterial embolizations. Conclusion Direct sac puncture and transarterial embolization of type II endoleak with aneurysm sac obliteration are similarly effective for the prevention of aneurysm sac growth. However, direct sac puncture is our preferred approach given its significantly shorter fluoroscopic and procedural times.

Central Venous Stenosis Associated with Pacemaker Leads: Short-Term Results of Endovascular Interventions

PURPOSE To determine the safety and outcomes of performing endovascular interventions across pacemaker (PM) lead-related central vein stenosis/occlusion. MATERIALS AND METHODS Clinical and imaging records from April 2002 to August 2010 were reviewed for patients presenting with clinically significant central venous stenosis or central venous obstruction with indwelling PM leads and were evaluated to determine if any lead dysfunction or complications occurred following intervention. Thirteen patients were identified who underwent 14 interventions. Outcomes were assessed based on recurrent clinical symptoms and repeat venograms, and patency was determined with Kaplan-Meier analysis. RESULTS All procedures were technically successful (100%) with no procedural complications. All patients underwent balloon angioplasty; two patients also underwent stent placement for persistent flow-limiting stenosis within the superior vena cava. No incidence of PM or lead dysfunction, infection, or need for PM intervention was identified in any patient at the time of the index procedure and at 30 or 90 days. In the two patients who received stents across PM leads, no manifestations of PM or lead dysfunction or infection, or need for intervention, were identified at 1 year after stent placement in one patient and at 3 years in the other patient. For eight patients, sufficient follow-up studies were available, with 30-, 60-, and 120-day primary patency rates of 87.5%, 75%, and 50%, respectively. CONCLUSIONS Endovascular interventions across PM leads resulted in no adverse clinical cardiac or PM sequelae, but with limited primary patency compared with historical outcomes for central venous interventions in the absence of PM leads.

Intraarterial Lidocaine for Pain Control in Uterine Artery Embolization: A Prospective, Randomized Study

PURPOSE To assess efficacy of two different techniques of lidocaine injection in the uterine arteries to reduce pain following uterine artery embolization (UAE) for leiomyomas. MATERIALS AND METHODS This prospective randomized single-blinded study was performed with 60 patients enrolled between November 2014 and December 2015 equally randomized to 3 arms. Group A received 10 mL lidocaine 1% (100 mg) mixed with polyvinyl alcohol particles (355-500 μm). Group B received the same dose of lidocaine injected after embolization. Group C was a control group. Pain was assessed on a 100-point visual analog scale at 4, 7, and 24 hours after the procedure. Narcotic agent dose to 24 hours was recorded. Outcomes were examined by analysis of variance and pairwise comparison. Leiomyoma infarction was assessed with magnetic resonance imaging 3 months after the procedure. RESULTS Technical success rate of UAE was 100%. Mean pain score at 4 hours was significantly lower in the lidocaine groups (group A, 28.6; group B, 35.8) compared with the control group (59.4; P = .001). Pain scores at 7 and 24 hours were not statistically different among the 3 arms. The mean in-hospital narcotic agent dose was significantly lower in both lidocaine groups than in the control group (group A, 8.5 mg [P = .002]; group B, 11.1 mg [P = .03]; group C, 17.4 mg). There were no adverse events related to the use of lidocaine. The number of patients with complete infarction of leiomyomas at 3 months was significantly lower in group A at 38.9% (group B, 77.8%; group C, 75%; P = .0451). CONCLUSIONS Lidocaine injected in the uterine arteries reduced postprocedural pain and narcotic agent dose after UAE. There were more cases of incomplete necrosis when lidocaine was mixed with the particles.

Effects of Pulsatile Fatigue on In Situ Antegrade Fenestrated Polyester Stent Grafts Deployed in a Patient-Specific Phantom Model of Juxtarenal Aortic Aneurysm

PURPOSE To evaluate the effects of in situ fenestration on the fabric of stent grafts deployed in a patient-specific phantom of a juxtarenal abdominal aortic aneurysm. MATERIALS AND METHODS Four patient-specific juxtarenal abdominal aortic aneurysm polyurethane models were created, and bifurcated Zenith (Cook, Inc, Bloomington, Indiana) and Endurant (Medtronic, Minneapolis, Minneapolis) endografts were deployed into the models, covering the renal arteries. Antegrade in situ fenestration was carried out with radiofrequency puncture followed by balloon dilation with either conventional or cutting balloons. Renal covered stents were deployed and flared. Specimens were mounted onto an accelerated fatigue tester for 40M cycles (1 patient life-year), and evaluated with microscopy, caliper measurements, and fabric counts. RESULTS Cutting balloons resulted in more fabric fraying. None of the fenestrations grew beyond the targeted 6-mm diameter despite accelerated fatigue. Fluoroscopic images demonstrated a very prominent waist of the renal fenestration in the Cook device when a conventional balloon was used compared with a cutting balloon. The average fenestration diameter for the Cook device was only 3.1 mm with the conventional balloon compared with 4.8 mm with the cutting balloon. The average fenestration diameter for the Medtronic device was 3.8 mm with the conventional balloon compared with 5.1 mm with the cutting balloon. The fabric counts suggested crowding of yarns around the fenestrations with conventional balloons but less with cutting balloons. CONCLUSIONS This experimental work suggests that the size of in situ renal fenestrations does not expand beyond the target diameter despite cyclic fatigue. Although the small number of devices tested and selected aortorenal anatomy in this study may limit conclusions, textile analysis suggests that cutting balloons should be used for the Cook Zenith device, whereas conventional balloons should be used for the Medtronic Endurant device when performing in situ fenestration.

Bridging stent-graft pullout force analysis.

Purpose To assess the pullout force (POF) of bridging stent-grafts used in thoracoabdominal stent-grafts and iliac bifurcated grafts. Methods In an experimental setup, the POFs of Viabahn or Fluency with or without a Zilver stent were measured when deployed into the renal and celiac branches of a Zenith thoracoabdominal cuff-bearing branched stent-graft. The POFs of the Atrium i-Cast, Viabahn, Fluency, and Fluency+Zilver were measured when deployed into an iliac bifurcated graft with a short side-branch for the internal iliac artery. At least 10 trials were performed for each stent in air at room temperature. Results The median POF (IQR; absolute range) required to dislodge each bridging stent-graft from the 6-mm renal branch was 1.89 N (0.47 N; 1.65–2.5) for the 7-mm Viabahn, 1.17 N (0.39 N; 0.68–1.57 N) for the 7-mm Fluency, and 2.08 N (0.49 N; 1.59–2.62 N) for the 7-mm Fluency with a supporting 8-mm Zilver stent (p<0.001). For the 8-mm celiac branch, the POFs were 2.79 N (0.82 N; 2.31–4.16 N), 1.74 N (0.18 N; 1.51–1.91 N), and 2.73 N (0.94 N; 1.9–3.61 N) for the 9-mm Viabahn, 9-mm Fluency, and 9-mm Fluency with a 10-mm Zilver stent, respectively (p<0.001). For the 8-mm internal iliac branch, the POFs were 3.53 N (0.85 N; 2.55–4.72 N) for the 9-mm i-Cast, 3.82 N (0.41 N; 3.29–4.45 N) for the 9-mm Viabahn, 2.32 N (0.23 N; 1.63–2.64 N) for the 9-mm Fluency, and 2.61 N (0.71 N; 1.65–3.63 N) for the 9-mm Fluency with a 10-mm Zilver stent (p<0.001). Conclusion There is a small but significant difference in pullout forces among various bridging stent-grafts. As pullout forces may be one factor contributing to type III endoleaks in complex endovascular repairs involving fenestrated and branched stent-grafts, further study is warranted to compare these grafts clinically to determine if they perform differently. According to this study, the theoretical advantages associated with the Viabahn stent-graft make it a strong choice for minimizing branch dislocations.