Target Vessel Catheterization Research Articles

Shuttering of the superior mesenteric artery during fenestrated endovascular aneurysm repair

Shuttering occurs when a scallop or fenestration does not align perfectly with the target vessel ostium and is potentially minimized by stenting. The current United States Food and Drug Administration-approved fenestrated endovascular aneurysm repair (f-EVAR) device is most commonly configured with an unstented superior mesenteric artery (SMA) scallop, thereby subjecting the SMA to risk of partial coverage. We aimed to describe the incidence, severity, and clinical effect of SMA shuttering during f-EVAR. Patients undergoing f-EVAR using the commercially available Zenith (Cook Medical, Bloomington, Ind) fenestrated stent graft system containing an SMA scallop at our institution between September 2012 and January 2014 were included for analysis. Corrected multiplanar reformatted images on postoperative computed tomographic angiography were reviewed to measure SMA shuttering, defined as the percentage of scallop misalignment relative to the SMA ostial diameter. Of the 28 f-EVAR cases performed at our institution during the study period, 18 patients (78% male) had an SMA scallop and were included in this analysis. The median age was 78 years (interquartile range [IQR], 72-81 years), and the median abdominal aortic aneurysm size was 61 mm (IQR, 56-64 mm). Fifty-one vessels were targeted (18 SMA scallops, 32 renal fenestrations, 1 renal snorkel), with covered stents placed in all fenestrations. Target vessel catheterization and successful branch stent deployment was achieved in 100% of patients. SMA shuttering measured on postoperative computed tomographic angiography of any amount occurred in 50% of patients (range of SMA shuttering, 12%-40%). The severity of SMA shuttering varied: one patient had 11% to 20%, four had 21% to 30%, and four had 31 to 40%. When compared with patients without shuttering, patients with any SMA shuttering were noted to have a shorter infra-SMA neck length (17 vs. 25 mm; P = .007), higher volume of intraprocedural contrast administration (100 vs. 66 mL; P = .001), and had a trend toward longer procedural durations (240 vs. 188 minutes; P = .09). No association was found between SMA shuttering and the preoperative measured clock position of the visceral vessels, percentage of device oversizing, number of target vessels per patient, aortic diameter at the SMA or seal zone, aneurysm neck morphology, infrarenal neck length, scallop width, or SMA ostial diameter. No acute or chronic events of mesenteric ischemia were noted during a median clinical follow-up period of 11 months (IQR, 5-14 months). Even with the custom design of currently available fenestrated technology, shuttering of the SMA occurred in one-half of the patients in our cohort, although no clinical events were noted. Further details of the incidence, magnitude, and tolerance of SMA shuttering during f-EVAR are warranted to fully understand the clinical implication of this radiographic finding. Future design considerations for advanced EVAR should take into account SMA shuttering to further refine operative planning.

Safety and efficacy of target vessel catheterization with the new steerable microcatheter Direxion compared with a standard microcatheter: a prospective, preclinical trial.

To assess the potential of a steerable microcatheter in a comparative preclinical trial. A total of 100 small target vessels of the lower limbs with a maximum diameter of 3mm were prospectively randomized to catheterize with either the preshaped torqueable Direxion™ (J tip shape; Boston Scientific, Natick, MA) or a similarly steam-shaped Renegade™ microcatheter (Boston Scientific) in a porcine model. Catheterization was first performed in combination with a microguidewire and afterwards without. No significant differences were found for the mean vessel diameter in the Direxion (1.53±0.44mm; n=50) or Renegade (1.62±0.43mm; n=50; p=0.35) group. Guidewire-assisted catheterization was successful in all target vessels, whereas access was achieved in most cases with the guidewire alone. However, when it became necessary to steer the Direxion actively, this was regarded as key to obtain vessel access in three of four target vessels (75%). Vessel catheterization without guidewire was significantly more successful with the Direxion (88%; n=44) compared with the Renegade (32%; n=16; p<0.0001). In addition, this catheterization technique was also significantly faster with the Direxion compared with guidewire-assisted vessel catheterization with the Renegade (16.1±14.4 sec compared with 27.1±24.7 sec; p=0.011). The Direxion microcatheter demonstrated unique steerability characteristics, which makes it a promising new tool especially for complex coaxial endovascular procedures.

Preloaded guidewires to facilitate endovascular repair of thoracoabdominal aortic aneurysm using a physician-modified branched stent graft

Branched stent grafts have been widely applied to treat complex aortic aneurysms. The technique often requires brachial or axillary approach to provide antegrade access to directional branches, which are bridged to target visceral arteries by self-expandable stent grafts. Preloaded guidewire catheterization may facilitate access into directional branches, decreasing or eliminating catheter manipulations required during this step of the procedure. We describe the use of a physician-modified branched stent graft using preloaded guidewire catheterization to treat a patient with recurrent, type III thoracoabdominal aortic aneurysm. The procedure was performed with no complications, and total operative time was 300 minutes, fluoroscopy time was 81 minutes, and iodinated contrast dose was 210 mL. Computed tomographic angiography revealed no endoleak and widely patent branches at 2 months.

Transcervical access in acute ischemic stroke

BackgroundLarge vessel occlusive disease portends a poor prognosis unless recanalization is rapidly achieved. Endovascular treatment is typically performed via a transfemoral approach, but catheterization of the occluded vessel can be...

Development of Off-the-shelf Stent Grafts for Juxtarenal Abdominal Aortic Aneurysms

IntroductionThe use of EVAR for more complex aneurysm anatomy has become more widespread over the past decade. Fenestrated and branched stent grafts for the visceral and iliac segment show promising short- and midterm outcome and these procedures have become routine in many vascular centers. However, at present, such grafts are customized to the individual patient and planning and manufacturing leads to significant treatment delay subjecting the patients to the risk of rupture during the waiting period. The purpose of this report is to describe the first experience in treating juxta/suprarenal aneurysms using the first version of a new fenestrated stent graft Material and MethodsA fenestrated device was designed with two renal fenestrations, an SMA fenestration and a scallop for the coeliac artery. The renal arteries were designed with an inner 6 mm fenestration and an outer 15 mm diameter creating a dome to allow renal artery catheterization for a range of renal artery distribution. Seven patients with complex visceral artery anatomy were treated with customized stent grafts containing these pivot renal fenestrations. ResultsTechnical success was uniform with 100% target vessel catheterization and 0% 30-day mortality. In one case, the graft was displaced slightly during delivery resulting in a renal artery stent occlusion at 2 months postoperatively. ConclusionsThe development of a modified fenestrated device has shown this to be feasible and it has the potential to reduce the need for extensive preoperative graft customization and establishing a true off the shelf platform for juxta- and suprarenal AAA.

Preloaded Fenestrated Stent-Grafts for the Treatment of Juxtarenal Aortic Aneurysms

To describe a novel technique for target vessel catheterization in patients with juxtarenal abdominal aortic aneurysms requiring treatment with fenestrated stent-grafts (FSG). The standard FSG design was modified, substituting a thin-wall tube for the solid central obturator that serves as both an attachment point for the distal end of the graft as well as a top cap retriever. Through this tube, two 0.020-inch wires are run from the hub of the delivery system through the stent-graft, out through each fenestration, and up to the proximal edge of the graft, where they are attached by sutures. The sutures are connected to a trigger wire on the control hub. The preloaded wires facilitate passage of a sheath to the fenestration, providing stability while target vessel catheterization takes place and avoiding the use of a large sheath in the contralateral groin. A third wire attached to the inside of the top cap facilitates its safe retrieval via a 6-mm balloon. The preloaded FSG was used in 5 male patients (mean age 75.6 years) with either juxtarenal aneurysms (n = 2) or aneurysms previously treated with infrarenal stent-grafts that had developed type I endoleak (n = 3). In 3 cases, a double fenestrated stent-graft was required, and in 2 cases a triple fenestrated device was deployed, with scallops for the superior mesenteric or celiac arteries. Sixteen of 17 target vessels were preserved, and all aneurysms were successfully excluded with no endoleak at completion. In 2 patients, tortuosity encountered during device delivery caused twisting of the wires within the preloaded FSG, preventing successful advancement of a sheath over a preloaded wire. An approach from the contralateral groin was necessary to complete the procedure in 1 case, but the target vessel was lost in the other. The use of a preloaded FSG is feasible and facilitates the catheterization of fenestrations and of target arteries. This method has the potential to reduce procedure times and lower the risk of intraoperative lower limb ischemia.

The role of robotic endovascular catheters in fenestrated stent grafting

Fenestrated stent grafting has allowed the treatment of complex thoraco-abdominal aneurysm disease via a totally endovascular approach, but the procedure can be technically challenging and time consuming. We investigated whether this procedure may be enhanced by remotely steerable robotic endovascular catheters. A four-vessel fenestrated stent graft partially deployed within a computed tomography (CT)-reconstructed pulsatile thoraco-abdominal aneurysm silicon model was used. Fifteen operators were recruited to participate in the study and divided into three groups, based on their endovascular experience: group A (n = 4, 100-200 endovascular procedures, group B (n = 5, 200-300), and group C (n = 6, >300). All operators were asked to cannulate the renal and visceral vessels under fluoroscopic guidance, using conventional and robotic techniques. Quantitative (catheterization times and wire/catheter tip movements) and qualitative metrics (procedure-specific-rating scale [IC3ST]), which grades operators on catheter use, instrumentation, successful cannulation/catheterization, and overall performance were compared. Median procedure time for cannulation of all four vessels was reduced using the robotic system (2.87 min, interquartile range [IQR; 2.20-3.90] versus 17.24 min [11.90-19.80]; P < .001) for each individual operator, regardless of the level of endovascular experience. The total number of wire/catheter movements taken to complete the task was also significantly reduced (38, IQR [29-57] versus 454 [283-687]; P < .001). There were significant differences in time and movement for cannulation of each individual vessel in the phantom. Robotic catheter operator radiation exposure was negligible as the robotic workstation is remote and away from the radiation source. Overall performance scores significantly improved using the robotic system, despite minimal operator exposure to this technology (IC3ST score 29/35, IQR [22.8-30.7] versus 19/35 [13-24.3]; P = .002). Each group of operators demonstrated an improvement in performance with robotic cannulation. For group A, median IC3ST score was 28/35, IQR (22-33) versus 15/35 (11-20); P = .04; for group B, 30/35 (27-31) versus 19/35 (18-24); P = .07; and for group C, 28.8/35 (28.5-29) versus 22/35 (16-24); P = .06. For groups B and C, these differences did not reach statistical significance. Robotic catheterization of target vessels during this procedure is feasible and minimizes radiation exposure for the operator. Steerable robotic catheters with intuitive control may overcome some of the limitations of standard catheter technology, enhance target vessel cannulation, reduce instrumentation, and improve overall performance scores.

The requirement for smart catheters for advanced endovascular applications

Endovascular techniques are well established in minimally invasive vascular surgery. Stent-graft technology is evolving. This will allow more complex aortic pathology to be treated. Current limitations in this equipment include the reliance on selective catheters along with trial and error to cannulate visceral or aortic arch branch vessels. This can lead to prolonged operations with increased radiation and contrast load to the patient with inevitable increase in peri-operative morbidity. A smart catheter that could expedite target vessel catheterization, minimize repeat catheter changes, and provide greater haptic feedback would enhance the endovascular surgeon's armamentarium. This would lead to broader and safer application of endovascular surgery.

Fenestrated endovascular repair for juxtarenal aortic pathology

To evaluate the outcomes after fenestrated endovascular aortic repair (f-EVAR) in a tertiary European referral center. All patients treated with commercially available custom-made f-EVAR between September 2002 and June 2007 were prospectively enrolled in a computerized database including co-morbidities and aneurysm morphology. Patients were retrospectively analyzed. Follow-up consisted of clinical examinations and computed tomography (CT) scanning. A total of 54 patients were included in this study. Median age was 72 (interquartile range [IQR] 68-76) years and 85% were men. Median preoperative aneurysm diameter was 60 (53-66) mm. One hundred thirty-four vessels were targeted (43 scallops, 91 fenestrations) and 96 stents were placed (69 bare, 27 covered). Target vessel catheterization was achieved in 98% of cases. Two patients (3.7%) died within 30 days, 1 from trash embolization and multiorgan failure and 1 from retroperitoneal bleeding caused by a renal artery perforation. Three type I endoleaks occurred intraoperatively, two sealed pre-discharge and one was treated with a Palmaz stent (Cordis, Miami Lakes, Fla) on postoperative day 4. Thirteen patients had type II endoleaks, and 2 required treatment. The median clinical follow-up was 25 (12-32) months with median CT follow-up of 22 (4-26) months. Aneurysm diameter decreased >or=5 mm in 47%, was unchanged in 50%, and increased >or=5 mm in 3% of patients at 1 year. There were three type II endoleaks at 1-year follow-up, one of which was successfully treated after 19 months due to aneurysm growth. Ninety-six percent of target vessels remained patent during the study period and all occlusions occurred within the first year of follow-up. Five target vessels occluded (2 renal arteries [RAs] and 3 superior mesenteric arteries [SMAs]) without symptoms during follow-up and successful reinterventions were done on 2 stenosed RAs. Three patients suffered creatinine increase but none needed dialysis. One late aneurysm-related death occurred due to massive bleeding during redo surgery for infection. Despite complex anatomy or severe comorbidities in these patients f-EVAR has acceptable short- and midterm results in this series which includes a learning curve and offers a valid treatment alternative to patients unsuitable for standard EVAR or open repair.

Simulation-based endovascular skills assessment: The future of credentialing?

Simulator-based endovascular skills training measurably improves performance in catheter-based image-guided interventions. The purpose of this study was to determine whether structured global performance assessment during endovascular simulation correlated well with trainee-reported procedural skill and prior experience level. Fourth-year and fifth-year general surgery residents interviewing for vascular fellowship training provided detailed information regarding prior open vascular and endovascular operative experience. The pretest questionnaire responses were used to separate subjects into low (<20 cases) and moderate (20 to 100) endovascular experience groups. Subjects were then asked to perform a renal angioplasty/stent procedure on the Procedicus Vascular Intervention System Trainer (VIST) endovascular simulator (Mentice Corporation, Gothenburg, Sweden). The subjects' performance was supervised and evaluated by a blinded expert interventionalist using a structured global assessment scale based on angiography setup, target vessel catheterization, and the interventional procedure. Objective measures determined by the simulator were also collected for each subject. A postsimulation questionnaire was administered to determine the subjects' self-assessment of their performance. Seventeen surgical residents from 15 training programs completed questionnaires before and after the exercise and performed a renal angioplasty/stent procedure on the endovascular simulator. The beginner group (n = 8) reported prior experience of a median of eight endovascular cases (interquartile range [IQR], 6.5-17.8; range, 4-20), and intermediate group (n = 9) had previously completed a median of 42 cases (IQR, 31-44; range, 25-89, P = .01). The two groups had similar prior open vascular experience (79 cases vs 75, P = .60). The mean score on the structured global assessment scale for the low experience group was 2.68 of 5.0 possible compared with 3.60 for the intermediate group (P = .03). Scores for subcategories of the global assessment score for target vessel catheterization (P = .02) and the interventional procedure (P = .05) contributed more to the differentiation between the two experience groups. Total procedure time, fluoroscopy time, average contrast used, percentage of lesion covered by the stent, placement accuracy, residual stenosis rates, and number of cine loops utilized were similar between the two groups (P > .05). Structured endovascular skills assessment correlates well with prior procedural experience within a high-fidelity simulation environment. In addition to improving endovascular training, simulators may prove useful in determining procedural competency and credentialing standards for endovascular surgeons.

Schizophrenia; birthrates and three Australian epidemics

Simulator-based endovascular skills training measurably improves performance in catheter-based image-guided interventions. The purpose of this study was to determine whether structured global performance assessment during endovascular simulation correlated well with trainee-reported procedural skill and prior experience level.Fourth-year and fifth-year general surgery residents interviewing for vascular fellowship training provided detailed information regarding prior open vascular and endovascular operative experience. The pretest questionnaire responses were used to separate subjects into low (<20 cases) and moderate (20 to 100) endovascular experience groups. Subjects were then asked to perform a renal angioplasty/stent procedure on the Procedicus Vascular Intervention System Trainer (VIST) endovascular simulator (Mentice Corporation, Gothenburg, Sweden). The subjects' performance was supervised and evaluated by a blinded expert interventionalist using a structured global assessment scale based on angiography setup, target vessel catheterization, and the interventional procedure. Objective measures determined by the simulator were also collected for each subject. A postsimulation questionnaire was administered to determine the subjects' self-assessment of their performance.Seventeen surgical residents from 15 training programs completed questionnaires before and after the exercise and performed a renal angioplasty/stent procedure on the endovascular simulator. The beginner group (n = 8) reported prior experience of a median of eight endovascular cases (interquartile range [IQR], 6.5-17.8; range, 4-20), and intermediate group (n = 9) had previously completed a median of 42 cases (IQR, 31-44; range, 25-89, P = .01). The two groups had similar prior open vascular experience (79 cases vs 75, P = .60). The mean score on the structured global assessment scale for the low experience group was 2.68 of 5.0 possible compared with 3.60 for the intermediate group (P = .03). Scores for subcategories of the global assessment score for target vessel catheterization (P = .02) and the interventional procedure (P = .05) contributed more to the differentiation between the two experience groups. Total procedure time, fluoroscopy time, average contrast used, percentage of lesion covered by the stent, placement accuracy, residual stenosis rates, and number of cine loops utilized were similar between the two groups (P > .05).Structured endovascular skills assessment correlates well with prior procedural experience within a high-fidelity simulation environment. In addition to improving endovascular training, simulators may prove useful in determining procedural competency and credentialing standards for endovascular surgeons.

Schizophrenia; do seasonal birthrates differ between the hemispheres?

Simulator-based endovascular skills training measurably improves performance in catheter-based image-guided interventions. The purpose of this study was to determine whether structured global performance assessment during endovascular simulation correlated well with trainee-reported procedural skill and prior experience level.Fourth-year and fifth-year general surgery residents interviewing for vascular fellowship training provided detailed information regarding prior open vascular and endovascular operative experience. The pretest questionnaire responses were used to separate subjects into low (<20 cases) and moderate (20 to 100) endovascular experience groups. Subjects were then asked to perform a renal angioplasty/stent procedure on the Procedicus Vascular Intervention System Trainer (VIST) endovascular simulator (Mentice Corporation, Gothenburg, Sweden). The subjects' performance was supervised and evaluated by a blinded expert interventionalist using a structured global assessment scale based on angiography setup, target vessel catheterization, and the interventional procedure. Objective measures determined by the simulator were also collected for each subject. A postsimulation questionnaire was administered to determine the subjects' self-assessment of their performance.Seventeen surgical residents from 15 training programs completed questionnaires before and after the exercise and performed a renal angioplasty/stent procedure on the endovascular simulator. The beginner group (n = 8) reported prior experience of a median of eight endovascular cases (interquartile range [IQR], 6.5-17.8; range, 4-20), and intermediate group (n = 9) had previously completed a median of 42 cases (IQR, 31-44; range, 25-89, P = .01). The two groups had similar prior open vascular experience (79 cases vs 75, P = .60). The mean score on the structured global assessment scale for the low experience group was 2.68 of 5.0 possible compared with 3.60 for the intermediate group (P = .03). Scores for subcategories of the global assessment score for target vessel catheterization (P = .02) and the interventional procedure (P = .05) contributed more to the differentiation between the two experience groups. Total procedure time, fluoroscopy time, average contrast used, percentage of lesion covered by the stent, placement accuracy, residual stenosis rates, and number of cine loops utilized were similar between the two groups (P > .05).Structured endovascular skills assessment correlates well with prior procedural experience within a high-fidelity simulation environment. In addition to improving endovascular training, simulators may prove useful in determining procedural competency and credentialing standards for endovascular surgeons.