The use of video motion analysis to determine the impact of anatomic complexity on endovascular performance in carotid artery stenting.

OBJECTIVE: Video motion analysis (VMA) uses fluoroscopic sequences to derive information on catheter and guidewire movement and is able to calculate two-dimensional catheter tip path length (PL) on the basis of frame-by-frame pixel coordinates. The objective of this study was to evaluate the effect of anatomic complexity on the efficiency of completion of defined stages of simulated carotid artery stenting as measured by VMA. METHODS: Twenty interventionists each performed a standardized easy, medium, and difficult carotid artery stenting case in random order on an ANGIO Mentor (Simbionix, Airport City, Israel) simulator. Videos of all procedures were analyzed using VMA software, and performance was expressed in terms of two-dimensional guidewire tip trajectory distance (PL). Comparisons of PL were used to identify differences in cannulation performance of the participants between the three cases of varying difficulty. The procedure was subdivided into four procedural phases: arch navigation, common carotid artery (CCA) cannulation, external carotid manipulation, and carotid lesion crossing. Comparisons of PL were used to identify differences in performance between the three cases of varying difficulty for each of the procedural phases. RESULTS: There were significant differences in PL in relation to anatomic complexity, with a stepwise increase in PL from easy to difficult cases: easy, median of 5000 pixels (interquartile range, 4075-5403 pixels); intermediate, 9059 (5974-14,553) pixels; difficult, 17,373 (11,495-26,594) pixels (P < .001). Similarly, during CCA cannulation, there was a stepwise increase in PL from easy to difficult cases: easy, 749 (603-1403) pixels; intermediate, 3274 (1544-8142) pixels; difficult, 8845 (5954-15,768) pixels (P < .001). There were no observed differences across the groups of anatomic difficulty for the phases of arch navigation, external carotid manipulation, and carotid lesion crossing. CONCLUSIONS: Increasing anatomic complexity leads to significant increases in PL of endovascular tools, in particular during CCA cannulation. This increase in tool movement may have a bearing on clinical outcome.

Robot-assisted uterine artery embolization: a first-in-woman safety evaluation of the Magellan System.

PURPOSE: To provide a technical description of robot-assisted uterine artery embolization and to investigate the safety and feasibility of the Magellan (Hansen Medical, Mountain View, California, USA) robotic catheter in this complex arterial bed. MATERIALS AND METHODS: Five women (mean age, 48.8 y) underwent robot-assisted bilateral uterine artery embolization over a 10-month period using the Magellan robotic catheter. Demographic, clinicopathologic, and endovascular performance metric data (fluoroscopy and cannulation times) were recorded as well as short-term outcomes. RESULTS: Robotic cannulation of bilateral internal iliac and uterine arteries was successful in all cases. Median right and left internal iliac artery cannulation and total fluoroscopy times were 3 minutes (interquartile range [IQR], 1.5-4 min), 2 minutes (IQR, 1.5-4 min), and 11 minutes (IQR, 9.5-14 min). Median right and left uterine artery cannulation times were both 11 minutes (IQR, 6.5-15 min and 8-12 min, respectively). Technical success was 100%. All patients were discharged on postoperative day 1, and there were no major or access site complications. At 6 months after the procedure, all patients reported significant improvement of symptoms, with a median increase in health-related quality-of-life score of 58% (48.5%-61.75%). CONCLUSIONS: The use of the new-generation Magellan system in uterine artery embolization is feasible and appears to be safe. The additional navigational capability and added maneuverability of the NorthStar catheter (Hansen Medical, Mountain View, California) may facilitate selective catheterization of small iliac artery divisions and may be useful in any procedure where complex arterial selection is needed.

Experience with a novel custom-made fenestrated stent graft in the repair of juxtarenal and type IV thoracoabdominal aneurysms.

OBJECTIVE: Fenestrated stent grafting has become increasingly popular as a means to manage complex aortic pathology, including juxta- and pararenal aneurysms. The design of a recently developed custom-made fenestrated stent graft, in theory, confers advantages when managing anatomically challenging aortic morphology. This study evaluated its feasibility in anatomically challenging scenarios. METHODS: Over a 12-month period, 20 patients received fenestrated stent grafts. Among those, 13 patients with juxtarenal or type IV thoracoabdominal aortic aneurysms underwent endovascular repair with the novel fenestrated stent graft at a single UK institution. Data on aneurysm morphology and immediate and short-term results were collected prospectively. RESULTS: The mean aneurysmal sac size was 7.3 cm (range, 5.5-10.0 cm). The mean infrarenal neck length was 4.4 mm (range, 0-9 mm), and in three cases was lined by a pre-existing infrarenal stent graft. Nine cases had an infrarenal neck angulation of 60(°) or more in either the anteroposterior or coronal planes. Five cases had ≥50% thrombus at the proximal landing zone. A total of 35 target vessels were cannulated, of which six right renal and four left renal arteries were angulated ≥120(°). Two-thirds of cannulated celiac trunks were angulated ≥120(°), and one cannulated superior mesenteric artery was angulated ≥ 140(°). Seven of the cannulated targets were stenosed more than 60%. One patient had two right renal arteries arising 3 mm from each other. Four right and four left common iliac arteries were angulated ≥90(°) in relation to the infrarenal aorta. Technical success was 100%. Median time from date of procedure to most recent follow-up with computed tomography scanning was 33 weeks. There was no type I or III endoleak. One type II endoleak was observed at the time of most recent computed tomography scanning and treated expectantly. There was a single incident of left renal artery occlusion. One patient required repair of a brachial artery, fasciotomies, and temporary haemofiltration. One patient died from ischemic heart disease 77 weeks after the procedure. CONCLUSIONS: The use of the novel fenestrated stent graft system in patients with hostile aortic aneurysmal morphology is feasible with acceptable short-term outcomes.

Preliminary comparative study of small amplitude helical and conventional ePTFE arteriovenous shunts in pigs.

Intimal hyperplasia (IH), which causes occlusion of arterial bypass grafts and arteriovenous (A-V) shunts, develops preferentially in low wall shear, or stagnation, regions. Arterial geometry is commonly three-dimensional, generating swirling flows, the characteristics of which include in-plane mixing and inhibition of stagnation. Clinical arterial bypass grafts are commonly two-dimensional, favouring extremes of wall shear. We have developed small amplitude helical technology (SwirlGraft) devices and shown them to generate physiological-type swirling flows. Expanded polytetrafluorethylene (ePTFE) grafts, although widely used as A-V shunts for renal dialysis access, are prone to thrombosis and IH. In a small preliminary study in pigs, we have implanted SwirlGraft ePTFE carotid artery-to-jugular vein shunts on one side and conventional ePTFE carotid artery-to-jugular vein shunts contralaterally. There was consistently less thrombosis and IH in the SwirlGraft than conventional shunts. At eight weeks (two animals), the differences were marked, with virtually no disease in the SwirlGraft devices and occlusion of the conventional grafts by thrombosis and IH. The study had limitations, but the lesser pathology in the SwirlGraft devices is likely to have resulted from their geometry and the associated swirling flow. The results could have implications for vascular biology and prolongation of the patency of arterial bypass grafts and A-V shunts.

Enhancing foot skin blood flux in peripheral vascular disease using intermittent pneumatic compression: controlled study on claudicants and grafted arteriopaths.

Intermittent pneumatic leg compression (IPC) increases arterial calf inflow and foot skin blood flux in normal subjects and claudicants. Our hypothesis was that IPC could enhance foot skin blood flux after infrainguinal grafting and thus promote distal perfusion in limbs with tissue loss. The aim of this study was to compare the effects of three IPC modes [applied to the foot (IPCfoot), the calf (IPCcalf), or both (IPCfoot+calf)] on foot skin perfusion in healthy individuals, claudicants, and patients after infrainguinal arterial revascularization performed for critical or subcritical limb ischemia. Altogether, 20 healthy limbs, 22 claudicating limbs, and 36 limbs of arteriopaths with prior successful autologous femoropopliteal and femorodistal (18 each) grafts were examined. Five-minute laser Doppler recordings were obtained from the pulp of the big toe in the sitting position, at rest, and during random applications of IPCfoot, IPCcalf, and IPCfoot+calf delivered at 120 mmHg for 4 seconds three times per minute. Foot skin blood flux increased using all IPC modes (p <0.001), with IPCfoot and IPCfoot+calf generating higher flux levels than IPCcalf (p <0.01) in all groups. Intergroup differences of flux with each of the three IPC modes were not significant. IPCfoot and IPCfoot+calf similarly (p > 0.14) produced a higher percentage flux increase than IPCcalf in all groups (p <0.004). Controls had a higher percentage flux increase with both IPCcalf and IPCfoot than did claudicants (p? 0.016). No differences were documented between normal and grafted limbs (p > 0.05). The percentage flux increase with IPCfoot+calf and IPCcalf was significantly higher in femorodistal grafts than in femoropopliteal ones (p ? 0.026). IPC enhances skin blood flux in limbs with infrainguinal bypass, claudication, and normal arteries, with IPCfoot and IPCfoot+calf being more effective than IPCcalf. Our findings suggest that IPC may be beneficial in limbs with impaired distal perfusion and thus may have clinical implications in the treatment of leg ulcers either prior to or after revascularization.