Intravascular ultrasound for transvenous interventions.

Since the development of intravascular ultrasound in the late 1980s, the modality has been used both to image the vascular system and to direct interventions in target vessels. Intravascular ultrasound (IVUS) was initially used to image atherosclerosis and aid in its treatment, but it has more recently been employed within the venous system, allowing for both intravenous and transvenous image-guided interventions. IVUS is now used for both direct and transjugular intrahepatic portosystemic shunt placement, for transcaval liver biopsy and transcaval puncture of type II endoleaks, and for cardiac mass biopsy, among other interventions. The use of IVUS not only yields potential for reduced fluoroscopy dose in and increased safety of established procedures, but it also allows for the development of altogether new procedures.

Dural venous sinus angioplasty and stenting for the treatment of idiopathic intracranial hypertension.

BACKGROUND: Lumboperitoneal shunt (LPS), ventriculoperitoneal shunt (VPS) and optic nerve sheath fenestration (ONSF) are accepted surgical therapies for medically refractory idiopathic intracranial hypertension (IIH). In the subset of patients with IIH and venous sinus stenosis, dural venous sinus stenting has emerged as an alternative surgical approach. METHODS: All cases of dural stents for IIH at our institution were retrospectively reviewed. Eligibility criteria included medically refractory IIH with documented papilledema and dural venous sinus stenosis of the dominant venous outflow system (gradient ≥10 mm Hg). RESULTS: Fifteen cases (all women) of mean age 34 years were identified. All had failed medical therapy and six had failed surgical intervention. Technical success was achieved in all patients without major periprocedural complications. The mean preprocedural gradient across the venous stenosis was reduced from 24 mm Hg before the procedure to 4 mm Hg after the procedure. Headache resolved or improved in 10 patients. Papilledema resolved in all patients and visual acuity stabilized or improved in 14 patients. There were no instances of restenosis among the 14 patients with follow-up imaging. CONCLUSION: In this small case series, dural sinus stenting for IIH was performed safely with a high degree of technical success and with excellent clinical outcomes. These results suggest that angioplasty and stenting for the treatment of medically refractory IIH in patients with dural sinus stenosis warrants further investigation as an alternative to LPS, VPS and ONSF.

Stent assisted coil embolization of unruptured middle cerebral artery aneurysms.

BACKGROUND: Due to anatomic features, including wide necks and incorporation of important branches, endovascular coiling of middle cerebral artery (MCA) aneurysms has proved challenging. Stent assisted embolization may increase the likelihood of successful treatment. METHODS: Consecutive patients undergoing stent assisted coil embolization utilizing the Neuroform stent from 2004 to 2009 were identified by hospital billing records. Procedural and clinical information-including procedure related mortality and morbidity and long term outcomes-were then obtained by retrospective chart review. RESULTS: Treatment was successful in 22/23 (96%) patients. Median age was 61 years and 16/22 (73%) were women. Aneurysm size was: <5 mm in 5/22 (23%); 5-9 mm in 14/22 (64%); and ≥10 mm in 3/22 (14%) patients. There were four periprocedural complications (including one stroke and one intraprocedural rupture), none associated with neurological dysfunction. Angiographic follow-up was available in 18/22 (82%) and clinical follow-up in 19/22 (86%) patients, both at a median of 1 year (mean 1.2 years) after coiling. Aneurysm occlusion was complete in 12/18 (67%), a neck remnant was present in 3/18 (17%) and persistent aneurysmal filling was present in 3/18 (17%) patients, requiring retreatment in 1/18 (6%) patient. In-stent stenosis of 50%, which was asymptomatic, occurred in 1/18 (6%) patient. No subarachnoid hemorrhages and no ischemic events related to the procedure were observed during follow-up. CONCLUSION: In this small series, the technical success rate was 96%, there were no transient or permanent neurological complications and complete aneurysmal occlusion was achieved in two-thirds of treated aneurysms on follow-up angiography. These results suggest that in appropriately selected patients, stent assisted coil embolization of MCA aneurysms can be performed with a high degree of safety and acceptable durability.

Outcomes of open operation for aortoiliac occlusive disease after failed endovascular therapy.

OBJECTIVES: To compare patient outcomes of primary open operation for aortoiliac occlusive disease (AIOD) with those of secondary open operations for failed endovascular therapy (ET) of AIOD. DESIGN: A retrospective cohort study was performed analyzing demographic characteristics, comorbidities, and outcomes. SETTING: Affiliated Veterans Affairs Hospital from January 1, 1998, through March 31, 2010. PATIENTS: Patients who underwent primary open operation for AIOD or secondary open operation for failed ET of AIOD. MAIN OUTCOME MEASURES: Overall survival and limb salvage. RESULTS: Primary open operations (n = 153) were 67 aortobifemoral grafts (43.8%), 38 axillobifemoral grafts (24.8%), and 48 femoral-femoral grafts (31.4%). Secondary open operations (n = 35) were 28 aortobifemoral grafts (80.0%), 5 axillobifemoral grafts (14.3%), and 2 femoral-femoral grafts (5.7%). Mean (SD) 5-year survival was 48.2% (5.6%) and 66.8% (10.0%), respectively, for patients undergoing primary vs secondary open surgery for AIOD (P = .01). There were 7 amputations during a mean follow-up of 3 years, all in the primary open surgery group. CONCLUSIONS: Despite a higher proportion of coronary artery disease and a 20% conversion of claudication to critical limb ischemia after failed ET for AIOD, survival was longer in patients undergoing secondary vs primary open surgery. Patients who underwent open surgery after failed ET for AIOD did not require amputation. Failed ET for AIOD does not lead to worse outcomes for patients undergoing open surgery for AIOD.

Comparing patient outcomes between multiple ipsilateral iliac artery stents and isolated iliac artery stents.

OBJECTIVE: Endovascular stents are accepted therapy for iliac artery stenoses and occlusions. Surgery is the recommended therapy for patients with severe iliac artery disease, including those with the combination of ipsilateral common iliac artery (CIA) and external iliac artery (EIA) stenoses/occlusions. This study compared patient outcomes, including late open conversion rates, for combined ipsilateral CIA and EIA stenting vs CIA or EIA stents alone. METHODS: Between 1998 and 2010, 588 patients underwent iliac artery stenting at two institutions. Patient comorbidities and outcomes were retrospectively reviewed, and analyses were performed using multivariate regression and Kaplan-Meier methods. RESULTS: There were 436 extremities with CIA stents, 195 with EIA stents, and 157 with CIA and EIA stents. The groups did not differ significantly in demographics, comorbidities, or treatment indications. During follow-up, 183 patients died, 95 underwent an endovascular reintervention, and 48 required late open conversion. For patients in the CIA or EIA stent group, the mean ± standard error survival was 5.3 ± 0.3 years, secondary endovascular intervention-free survival was 7.4 ± 0.6 years, late open conversion-free survival was 9.8 ± 0.4 years, and amputation-free survival was 7.6 ± 0.4 years. In the CIA and EIA stent group, survival was 6.1 ± 0.6 years, secondary endovascular intervention-free survival was 7.2 ± 0.6 years, late open conversion-free survival was 9.0 ± 1.1 years, and amputation-free survival was 8.4 ± 0.5 years. Survival, reintervention-free survival, late open conversion-free survival, and amputation-free survival were all similar between patient groups (all P > .05). CIA and EIA stenting in combination was not a predictor of death, reintervention, late open conversion, or amputation. CONCLUSIONS: Outcomes are similar for patients with CIA or EIA stents and for those with combined ipsilateral CIA and EIA stents. Late open conversions for iliac artery stent failure are uncommon and not influenced by the location or extent of prior iliac artery stent placement. Endovascular therapy for aortoiliac disease should be extended to consider selected patients with ipsilateral CIA and EIA stenoses/occlusions.

Stent-grafts in the treatment of emergent or urgent carotid artery disease: review of 25 cases.

PURPOSE: To report the authors' initial experience with carotid artery stent-grafts in a comparatively large patient series for the treatment of acute bleeding and impending rupture or the prevention of distal embolization. MATERIALS AND METHODS: This retrospective study was approved by the institutional review boards and performed according to HIPPA standards. Twenty-five patients were treated with 27 carotid artery stent-grafts (Gore Viabahn, n = 10; Bard Fluency, n = 9; polytetrafluoroethylene-covered Palmaz, n = 5; and Wallgraft, n = 3). Thirteen stent-grafts were placed in patients with carotid blow-out syndrome (including three patients with carotid-airway fistula), 12 in patients with either pseudoaneurysm (n = 9) or true aneurysm (n = 3), and two in patients with intractable high-grade bare stent restenosis. RESULTS: The technical success rate was 100% (27 of 27 cases). No acute procedural transient ischemic attacks or strokes occurred. Procedural dissections occurred in two of the 27 cases (7.4%). Short-term complications occurred in three of the 27 cases (11%) (repeat hemorrhage, n = 2; common carotid artery occlusion, n = 1). The overall patient mortality rate was 36% (nine of 25 patients, all with carotid blow-out syndrome). Six-month follow-up in 15 of the 16 living patients demonstrated widely patent stent-grafts. Two patients with pseudoaneurysm also demonstrated patent stents at 18- and 33-month follow-up. CONCLUSIONS: Stent-grafts may be useful in the treatment of carotid artery bleeding syndrome, aneurysm, and stenosis, with a high procedural success rate in selected cases. The results of mid-term follow-up are encouraging, but results of long-term follow-up must be evaluated in future studies.

Intravascular US-guided direct intrahepatic portocaval shunt with an expanded polytetrafluoroethylene-covered stent-graft.

PURPOSE: To retrospectively evaluate the midterm patency rate of the nitinol (Viatorr, W.L. Gore and Associates, Flagstaff, Ariz) stent-graft for direct intrahepatic portacaval shunt (DIPS) creation. MATERIALS AND METHODS: Institutional Review Board approval for this retrospective HIPAA-compliant study was obtained with waiver of informed consent. DIPS was created in 18 men and one woman (median age, 54 years; range, 45-65 years) by using nitinol polytetrafluoroethylene (PTFE)-covered stent-grafts. The primary indications were intractable ascites (n = 14), acute variceal bleeding (n = 3), and hydrothorax (n = 2). Follow-up included Doppler ultrasonography at 1, 6, and 12 months and venography with manometry at 6-month intervals after the procedure. Shunt patency and cumulative survival were evaluated by using the Kaplan-Meier method and survival curves were plotted. Differences in mean portosystemic gradients (PSGs) were evaluated by using the Student t test. Multiple regression analysis for survival and DIPS patency were performed for the following parameters: Child-Pugh class, model of end-stage liver disease score, pre- and post-DIPS PSGs, pre-DIPS liver function tests, and pre-DIPS creatinine levels. RESULTS: DIPS creation was successful in all patients. Effective portal decompression and free antegrade shunt flow was achieved in all patients. Intraperitoneal bleeding occurred in one patient during the procedure and was controlled during the same procedure by placing a second nitinol stent-graft. The primary patency rate was 100% at all times during the follow-up period (range, 2 days to 30 months; mean, 256 days; median, 160 days). Flow restrictors were deployed in two (11%) of 19 patients. The 1-year mortality rate was 37% (seven of 19). CONCLUSION: Patency after DIPS creation with the nitinol PTFE-covered stent-graft was superior to that after TIPS with the nitinol stent-graft.

Direct intrahepatic portocaval shunt.

The direct intrahepatic portacaval shunt (DIPS) is a modification of the TIPS procedure, using intravascular ultrasound-guidance, combined with fluoroscopy. The DIPS procedure was initially conceived to increase the durability of shunt patency and extend the spectrum of patients with portal hypertension for whom endovascular portocaval shunting can be performed. The DIPS procedure involves intravascular ultrasound-guided puncture from the inferior vena cava to the portal vein through the caudate lobe of the liver. The shunt is completed with a polytetrafluoroethylene-covered stent graft. This article describes the indications, technique, and outcomes of the DIPS procedure to enable the interventional radiologist currently experienced with TIPS to incorporate this procedure into their practice.

Safety of inferior vena cava filter retrieval in anticoagulated patients.

PURPOSES: To evaluate the safety of inferior vena cava (IVC) filter retrieval in therapeutically anticoagulated patients in comparison to prophylactically or not therapeutically anticoagulated patients with respect to retrieval-related hemorrhagic complications. MATERIALS AND METHODS: This was a retrospective study of 115 consecutive attempted IVC filter retrievals in 110 patients. Filter retrievals were stratified as performed in patients who were therapeutically anticoagulated (group 1), prophylactically anticoagulated (group 2), or not therapeutically anticoagulated (group 3). The collected data included anticoagulant and antiplatelet medications (type, form and duration of administration, dosage) at the time of retrieval. Phone interviews and chart review was performed for the international normalized ratio (INR), activated partial thromboplastin time, platelet count, infusion of blood products, and retrieval-related hemorrhagic complications. RESULTS: Group 1 included 65 attempted filter retrievals in 61 therapeutically anticoagulated patients by measured INR or dosing when receiving low-molecular-weight heparin (LMWH). Four retrievals were not successful. In patients receiving oral anticoagulation, the median INR was 2.35 (range, 2 to 8). Group 2 comprised 23 successful filter retrievals in 22 patients receiving a prophylactic dose of LMWH. Group 3 included 27 attempted filter retrievals in 27 patients not receiving therapeutic anticoagulation. Six retrievals were not successful. Five patients were receiving oral anticoagulation with a subtherapeutic INR (median, 1.49; range, 1.16 to 1.69). No anticoagulation medication was administered in 22 patients. In none of the groups were hemorrhagic complications related to the retrieval procedures identified. CONCLUSIONS: These results suggest that retrieval of vena cava filters in anticoagulated patients is safe. Interruption or reversal of anticoagulation for the retrieval of vena cava filters is not indicated.

A flexible stent with small intestinal submucosa covering for direct intrahepatic portocaval shunt: experimental pilot study in swine.

The suitability of the flexible sandwich Zilver stent-graft (SZSG) with a biologically active tissue layer (small intestinal submucosa) for creation of the intravascular ultrasound (IVUS)-guided direct intrahepatic portocaval shunt (DIPS) was explored in six young swine in a search for a flexible system to replace the rigid polytetrafluoroethylene (PTFE) stent originally used by this group with limited success. The portal vein was punctured from the inferior vena cava through the caudate lobe of the liver using IVUS guidance. After balloon dilation of the puncture tract, DIPS was successfully created in all animals with use of an SZSG 9 mm in diameter and 6 cm or 8 cm long. Only one DIPS remained well patent at 14 days when the animal had to be killed because of encephalopathy. DIPS in the other five animals were found to be either severely stenosed (3 animals) or occluded (2 animals) at 4 weeks due to accelerated formation of neointimal hyperplasia (NIH) in the liver parenchymal portion of the shunt and superimposed thrombosis. The lack of high pressure in the portal system contributed to early endograft closure. The flexible stent and the covering fail badly. The reason for this could be due to either component. More work is required to find a reliable flexible system with long-term patency. Exploration of the IVUS-guided direct extrahepatic portocaval shunt is suggested.

Peripheral vascular disease: blinded study of dedicated calf MR angiography versus standard bolus-chase MR angiography and film hard-copy angiography.

PURPOSE: To compare the accuracy of contrast material-enhanced three-dimensional (3D) dedicated calf magnetic resonance (MR) angiography with that of bolus-chase MR angiography, with conventional angiography as the reference standard, in patients with symptomatic peripheral vascular disease (PVD). MATERIALS AND METHODS: Thirty men with symptomatic PVD were examined. MR angiography was performed at 1.5 T before conventional angiography. MR angiographic examination included 3D contrast-enhanced dedicated calf MR angiography and three-station bolus-chase MR angiography. Two radiologists blinded to conventional angiographic results evaluated the MR angiograms independently. Two angiographers evaluated the conventional angiograms in consensus. Calf artery segments were graded as having 50% or less stenosis, greater than 50% stenosis, or occlusion or as being nondiagnostic. Statistical analyses were performed with paired permutation testing. RESULTS: Analyses of 472 calf segments and 420 pelvic and thigh segments were performed. Of the 472 calf segments, three and 75 segments (reader 1) and seven and 91 segments (reader 2) were graded as nondiagnostic at dedicated calf MR angiography and bolus-chase MR angiography, respectively. Differences in diagnostic grade between the two examinations were significant (P <.001), accounting for within-subject correlations, with a mean estimated difference of -17.1% (95% confidence interval [CI]: -25.8%, -8.4%). In the calf arteries, the dedicated and bolus-chase MR angiographic sequences had diagnostic accuracies, respectively, of 81.5% (reader 1) and 79.1% (reader 2) and of 67.8% (reader 1) and 63.4% (reader 2). The dedicated calf sequence was significantly more accurate than the bolus-chase sequence (P =.001). The point estimate of the difference was 14.7%, with estimated correct diagnosis rates of 80.3% and 65.6% for the dedicated calf and bolus-chase examinations, respectively (95% CI for difference: 4.0%, 25.4%). The diagnostic accuracy of bolus-chase MR angiography at the pelvis-thigh level was slightly higher when it was performed first: 81.9% (reader 1) and 83.8% (reader 2) versus 74.3% (reader 1) and 80.0% (reader 2) when it was performed last. The difference was not significant (P =.21). CONCLUSION: Use of dedicated calf MR angiography led to significantly increased diagnostic accuracy in the calf arteries compared with standard bolus-chase MR angiography. Use of the dual-bolus technique did not jeopardize the diagnostic accuracy in the pelvic and thigh arteries.

Clinical outcome after intrahepatic venous stent placement for malignant inferior vena cava syndrome.

We evaluated the clinical outcome of malignant inferior vena cava (IVC) syndrome after intrahepatic IVC stent placement by retrospective analysis of 50 consecutive patients (25 men, 25 women, age 32-83 years) with malignant IVC syndrome who were treated with intrahepatic stent placement. Gianturco-Rosch-Z (GRZ) stents (n = 45), and Wallstents (n = 5) were inserted. Clinical outcome was assessed from patients' records using a score based on leg swelling, scrotal/vulvar edema, ascites and anasarca before and after stent placement, as well as at last follow-up visit before death. Clinical follow-up was supplemented by duplex sonography in 36 patients. Inferior venocavography was performed in 5 patients prior to re- intervention. Follow-up time ranged from 1 to 932 days (mean 62 days). Mean pressure gradient in the IVC was reduced from 14 +/- 4.1 mmHg before to 2.9 +/- 3.2 mmHg after stent placement (p < 0.001). Four patients had stent occlusion, 2 of whom were successfully re-stented. Primary and secondary patency was 59% and 100%, respectively at 540 days. Immediate clinical data were available in 44 patients: 38 improved; 6 did not respond. Last follow-up visit data were available in 36 patients: 24 showed persistent symptom relief till death. All symptom scores were significantly improved after stent placement (p < 0.001) and with the exception of ascites, remained significantly improved (p < 0.05) until the last follow-up. Increased serum bilirubin was a common characteristic of clinical failures and recurrences. Intrahepatic IVC stent placement resulted in significant symptomatic relief in patients with malignant IVC syndrome. Palliation was effective even in patients with a very short life expectancy.

Two fatal complications after parallel tracheal-esophageal stenting.

Two patients with malignant obstructions of both the trachea and esophagus underwent parallel stent placement with Gianturco-Rösch Z (GRZ) stents for palliation of symptoms. Fatal hemorrhage occurred in both patients 2 and 3 weeks after stent placement respectively. An autopsy performed on one of these patients demonstrated esophageal tissue necrosis and erosion with perforation of both the tracheal and esophageal walls at sites where the stent struts were in direct opposition, leading to bleeding from the esophageal venous plexus. GRZ stents have been successful in the treatment of both solitary tracheal and esophageal stenoses. However, parallel tracheal-esophageal stenting with GRZ stents places patients at high risk for complications due to the high radial force exerted by this particular stent and the minimal amount of intervening tissue between the two structures.