Monitoring of gadolinium-BOPTA uptake into the vessel wall during magnetic resonance (MR)-guided angioplasty of the peripheral arteries with a paclitaxel/gadolinium-BOPTA-coated balloon: an experimental study at 3 Tesla.

PURPOSE: The success of paclitaxel distribution within the vessel wall during paclitaxel-coated balloon angioplasty to prevent restenosis cannot be monitored under X-ray guidance. The aim of this pilot study was to demonstrate the feasibility of monitoring Gadolinium-BOPTA delivery within the vessel wall during magnetic resonance (MR)-guided paclitaxel/Gadolinium-BOPTA-coated balloon angioplasty of the peripheral arteries. MATERIALS AND METHODS: 6 pigs (47 ±â€Š2 kg) were investigated. All experiments were performed using a 3 Tesla MR scanner. MR-guided bilateral angioplasty of the iliac arteries was performed using a paclitaxel/MR contrast agent-coated balloon catheter. The feasibility of monitoring the delivery of Gadolinium-BOPTA to the vessel wall was assessed in 4 animals. In two additional animals, bilateral stenosis was surgically induced in the iliac arteries. Delivery of paclitaxel to the vessel wall was monitored using a 3 D T1-weighted gradient echo (GE) sequence for delineation of the vessel wall. Normalized signal intensity (SI) of the vessel wall was measured before and repeatedly after the intervention for 45 min. in all animals. RESULTS: Paclitaxel/gadolinium-BOPTA-coated balloon angioplasty was successfully accomplished in all iliac arteries (n = 12). In animals with stenosis MR-angiography demonstrated successful dilatation (n = 4). The normalized SI of the vessel wall on T1-weighted GE images significantly increased after the intervention in all animals with and without stenosis for more than 45 min. (p < 0.001). CONCLUSION: Monitoring of Gadolinium-BOPTA into the vessel wall during MR-guided coated balloon angioplasty is feasible. This is a first step towards providing a tool for the online control of homogenous drug delivery after paclitaxel-coated balloon angioplasty. KEY POINTS: • Monitoring of gadolinium-BOPTA uptake into the vessel wall during MR-guided coated balloon angioplasty is feasible.• Endovascular MR-guided interventions on a 3 Tesla MR scanner are feasible.• This is a first step towards providing a tool for online control of homogenous drug delivery after paclitaxel-coated balloon angioplasty.

Herpes simplex virus type-I and pyogenic granuloma: a vascular endothelial growth factor-mediated association?

Pyogenic granuloma (PG) is a vascular endothelial growth factor (VEGF)-related neoangiogenic process. Minor trauma, chronic irritation, certain drugs and pregnancy may favor PG. Viral triggers have not been reported up to date. A 52-year-old woman with hairy-cell leukemia presented because of a 3-month history of a giant pseudotumoral lesion on her left cheek. All prior antibacterial, antifungal and anti-inflammatory treatments had failed. Histology revealed PG with sparse and isolated epithelial cell aggregates. Immunohistochemistry (IHC) identified herpes simplex virus type-I (HSV-I) antigens in the nuclei and cytoplasm of normal-appearing as well as cytopathic epithelial cells, suggesting a chronic, low-productive HSV infection. No HSV-I signal was evidenced in the endothelial cells of the PG. Furthermore, IHC revealed VEGF in the HSV-I infected epithelial cells as well as within the PG endothelial cells. These results incited oral treatment with valaciclovir, and the PG promptly resolved after 2 weeks. These findings suggest that a chronic HSV-I infection might play an indirect, partial role in neoangiogenesis, presumably via HSV-I infection-related stimulation of keratinocytic VEGF production.

Ultrasound thrombolysis in hemodialysis access: in vitro investigation.

PURPOSE: To evaluate the effectiveness of ultrasound thrombolysis in occluded hemodialysis access shunts using an in vitro model. METHODS: Thrombosed hemodialysis accesses were simulated by clotted bovine blood in a flow model (silicone tubing; inner diameters 4, 6, and 9 mm). After retrograde and antegrade sheath placement (7 Fr), mechanical thrombolysis was performed using an ultrasound probe (Acolysis, Angiosonics, Morrisville, NC, USA). The tip of the device measured 2.2 mm in diameter. During sonication, the catheter was moved slowly back and forth using an over-the-wire system. Thirty complete occlusions [tubing diameters 4 mm (n = 12), 6 mm (n = 12), 9 mm (n = 6)] were treated. Initial thrombus weights were 3.5 (+/- 0.76) g, 7.7 (+/- 1.74) g, and 19.4 (+/- 2.27) g for the three diameters. Maximum sonication time was 15 min for each probe. RESULTS: With this device, we were able to restore a continuous lumen in all 12 occluded 4 approximately mm silicone tubes. No wall-adherent thrombi remained after sonication for 3.5--9.6 min. In hemodialysis access models with diameters of 6 mm, thrombus fragments persisted in 25% (3/12 accesses). These were located in the medial portion of the access loop and near to the puncture sites. However, flow was re-established after 5.0--13.0 min of treatment in all settings. Mechanical dissolution of thrombus material failed in five of six access models with diameters of 9 mm, even though ultrasound energy was applied for the maximum of 15 min. CONCLUSION: In a clotted hemodialysis shunt model, successful ultrasound thrombolysis was limited to small access diameters and small amounts of thrombus.

MR evaluation of stent patency: in vitro test of 22 metallic stents and the possibility of determining their patency by MR angiography.

RATIONALE AND OBJECTIVES: To determine the extent to which visualization of intrastent anatomy in stents of different composition and design is possible by using contrast-enhanced MR angiography. METHODS: Twenty-two MR-compatible stents, most of which had a diameter of 8 mm, were positioned in a phantom filled with aqueous gadolinium solution. Coronal and axial spoiled three-dimensional gradient-echo sequences were performed. Images were acquired with stents positioned at varying angulations to the main magnetic field B0. Profiles orthogonal to the stent axis allowed measurement of artifact sizes independent of window width and center. RESULTS: Oriented along B0, the Cragg, Corvita, Passager, Wallstent, Strecker, Impag, Perflex, and ZA stents allowed visualization of more than 48% of the lumen. The Memotherm, Smart, and Jostent SelfX stents showed a prominent reduction of the inner lumen to below 41%. The lumina of the covered Jostent, Palmaz, Sinus, and Symphony stents were completely obscured. The Impag, Perflex, and Strecker tantalum stents showed growing artifact sizes and a lumen reduction of at least 40% with increasing angulation to B0. CONCLUSIONS. Evaluation of the inner stent lumen by applying contrast-enhanced, three-dimensional gradient-echo sequences is not possible for the majority of stents because of their large artifacts. These depend on the stent type and orientation to B0. Even stents made of nitinol and cobalt alloys only allow qualitative patency assessment but no quantification of stenosis.

[Diagnosis and visualization of renal artery stenosis by color-coded Doppler ultrasonography. Comparison of central and peripheral flow patterns]. / Diagnostik und Darstellung von Stenosen der Arteria renalis mittels Farbkodierter Dopplersonographie. Vergleich von zentraler und peripherer Flussableitung.

PURPOSE: Comparison between central and peripheral flow patterns with color-coded duplex sonography in the diagnosis of renal artery stenosis. MATERIALS AND METHODS: In a prospective study with sixty-six patients systolic velocity (central examination) and acceleration index (peripheral examination) were determined using color-coded duplex sonography examination in order to detect and visualize renal artery stenosis. If the central and peripheral measurements were negative, no angiography was performed. In contrast, if one of the methods yielded a pathological finding, catheter angiography was performed to verify the results (21 patients), as well as in two other unclear cases. RESULTS: An agreement between central and peripheral measuring was seen in 49 of 66 patients. In ten patients central and peripheral measurements showed different results. In seven cases the peripheral measurements were not clear. Compared to angiography, peripheral measurement showed a sensitivity of 60%, a specificity of 75% and a positive predictive value of 81.8%. In contrast, central examination had a sensitivity of 100%, a specificity of 75% and a positive predictive value of 88.2%. CONCLUSIONS: Based on our preliminary results, the measurement of the systolic velocity peak seems to be an effective method to detect renal artery stenosis.

Arteriovenous fistulas induced by femoral arterial catheterization: percutaneous treatment.

PURPOSE: To evaluate the use of stent-grafts for the percutaneous closure of arteriovenous fistulas that develop after cardiac catheterization. MATERIALS AND METHODS: From January 1994 to November 1997, 14 arteriovenous fistulas in 13 patients (eight men, five women; age range, 46-65 years; mean age, 53.5 years) were treated. Eleven fistulas were situated between the deep femoral artery and the common femoral vein, and three fistulas were between the superficial femoral artery and the common femoral vein. All fistulas were closed with stent-grafts positioned in the artery at the level of the fistula. RESULTS: The percutaneous treatment of arteriovenous fistulas was successful in all cases. The findings at angiography performed after the procedure demonstrated the closure of the fistulas and the correct positioning of the prostheses; veins were no longer visible. One complication occurred--a partial thrombosis of the common femoral vein at the puncture site after manual compression. CONCLUSION: On the basis of the preliminary data, the authors believe that the percutaneous closure of arteriovenous fistulas with stent-grafts is a safe and effective alternative to conventional surgery.

Percutaneous endoluminal bypass of iliac aneurysms with a covered stent.

To evaluate the feasibility of percutaneous treatment of iliac aneurysms, a covered stent was inserted in nine men suffering from common iliac artery aneurysms (six cases), external iliac aneurysms (one case), or pseudoaneurysms (two cases). Placement of the stent was successful in all patients. In one patient, an endoprosthesis thrombosed after 15 days, but was successfully treated by thrombolysis and additional stent placement. At the follow-up examinations (mean period 22 months) all stent-grafts had remained patent. No late leakage or stenosis was observed.

Feasibility of intraoperative balloon angioplasty and additional stent placement of isolated stenosis of the brachiocephalic trunk.

OBJECTIVE: We sought to evaluate the feasibility and results of intraoperative balloon angioplasty and additional stent placement of isolated stenosis of the brachiocephalic trunk. PATIENTS AND METHODS: Between May 1993 and October 1996, we treated eight patients with local stenosis of the innominate artery. Seven lesions were situated in the proximal and one in the middle third of the brachiocephalic trunk. Five patients were men and three were women, with ages ranging from 55 to 72 years (mean 59.5 years). All stenoses provoked severe blood flow reduction and caused clinical symptoms. Procedures were performed in an operating suite with fluoroscopic imaging capabilities. Through an anterolateral cervical approach the right common carotid artery was surgically exposed and then clamped to avoid atheroembolization during the subsequent procedure. Retrograde catheterization was performed to reach the stenosis of the brachiocephalic trunk. The lesion was dilated with a balloon catheter and successively stented. Follow-up examinations (color-coded duplex sonography, accompanied by clinical inspection and systolic blood pressure) were scheduled every 6 months. RESULTS: In all patients the dilation of the stenosis of the innominate artery and the stent placement were successful without any side effects. No embolic events or other complications occurred. The postintervention angiography showed successfully dilated stenoses and patent stents in all cases. The technical success rate was 100%. CONCLUSIONS: On the basis of our preliminary data, we believe that, in selected patients, intraoperative balloon angioplasty of stenosis of the innominate artery with stent placement from the right common carotid artery approach is a safe and effective alternative to conventional operations.

Exclusion of an internal carotid aneurysm by a covered stent.

The authors report a case of a patient with thromboembolic strokes caused by a high internal carotid artery aneurysm. Considering the position and the anatomic structure of this aneurysm the sac was excluded transluminally by placing an endovascular covered stent.

Combined surgical and endovascular treatment of a traumatic pseudo-aneurysm of the brachiocephalic trunk with anatomical anomaly.

The authors report a case of combined surgical and endovascular treatment of a traumatic pseudo-aneurysm of the innominate artery in which the left common carotid artery originated from the brachiocephalic trunk. After a conventional surgical intervention with the implantation of the left common artery on the left subclavian artery, to correct the anatomic anomaly, a safe and effective endovascular stent-graft placement excluded the aneurysm. This new technique proposes a good chance for polytraumatized patients to receive a better prognosis and a much faster rehabilitation.