bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analytical Modeling and Numerical Simulation of Forces in an Endoluminal Graft
Authors: Liffman Kurt , Lawrence-Brown Michael M.D. , Semmens James B. , Bui Anh , Rudman Murray , Hartley David E. 
Published: March 2015

Purpose: To utilize mathematical analysis and computational fluid dynamics (CFD) to investigate the forces acting within the pressurized aorta and upon a stent-graft and how these forces may affect the ongoing performance of the stent-graft. Methods: Analytical force balance analysis and CFD simulations using the Fluent code were used to mimic blood flow through a bifurcated stent-graft in a person at rest. Steadystate blood flow was assumed in which the inlet pressure approximated the mean blood pressure (100 mm Hg) and the blood flow velocity was an approximation of the peak systolic flow rate (0.6 m/s). Two sizes of endoluminal grafts were analyzed: the larger graft had an inlet diameter of 3 cm and outlet diameters of 1 cm; the smaller graft diameters measured 2.4 cm proximally and 1.2 cm distally. The endografts were studied in 2 configurations: with the limbs straight and with one bent. Results: For the larger graft model, the normal peak blood flow induced a downward force of 7 to 9 N on the bifurcated grafts. Bending one of the limbs of the graft produced a sideways force of 1.3 N. For the smaller endograft, the downward force was in the range of 3.1 to 5.1 N and the sideways force on a curved limb was ∼1.5 N. The magnitude of the forces given by the analytical formulae and the CFD results agreed to within 2 significant figures. Conclusions: These results suggest that the downward force on a bifurcated stent-graft, which may exceed the force required to dislodge it when relying on radial attachment alone, is determined mostly by the proximal graft diameter. Curvature of the graft limbs creates an additional sideways force that works to displace the distal limbs of the graft from the iliac arteries.
Thrombus Formation in Aortic Endografts
Authors: Wegener Martin , Görich Johannes , Krämer Stefan , Fleiter Thorsten , Tomczak Reinhard , Scharrer-Pamler Reinhard , Kapfer Xaver , Brambs Hans-Jürgen 
Published: March 2015

Purpose: To examine the incidence of intraprosthetic thrombotic deposits in aortic endografts. Methods: Transfemoral implantation of tube or bifurcated stent-grafts was performed in 82 patients (75 men; average age 67.7 years, range 25–88) for treatment of aneurysms of the abdominal (n = 73) or thoracic (n = 9) aorta in a 3.5-year period. Patients underwent 3-phase helical computed tomographic (CT) examinations at 3-month intervals. The length and cross-sectional area of any thrombotic deposits were measured from axial and 3-dimensional CT images. Results: Over a 12.1-month mean follow-up, intraluminal deposits of thrombotic material were observed in 19 (23.2%) patients, all with infrarenal endografts that were predominately of a bifurcated design. The first signs of thrombus formation occurred on average 7 months postoperatively (range 1 week to 20 months). In 16 patients, nonocclusive deposits of thrombotic material were seen in the aortic segment of the endograft; a graft limb was involved in 5 patients. Three graft limbs occluded owing to kinking; no thrombus was seen on CT scans taken prior to occlusion. In 3 cases the thrombotic deposits disappeared completely from the prosthesis lumen during follow-up. Conclusions: Based on this small experience, nearly 1 in 5 patients may experience some degree of intraluminal thrombus following endovascular treatment of aortic aneurysms. Whether the deposition of thrombus is influenced by the geometry of the aortic stent-graft or by flow conditions within the prosthetic lumen must be determined in future studies.
Endovascular Repair of Iatrogenic Subclavian Artery Perforations Using the Hemobahn Stent-Graft
Authors: Bartorelli Antonio L. , Trabattoni Daniela , Agrifoglio Marco , Galli Stefano , Grancini Luca , Spirito Rita 
Published: March 2015

Purpose: To report the use of a new self-expanding endograft for percutaneous treatment of iatrogenic subclavian artery perforations. Case Reports: The subclavian artery of 2 patients was inadvertently cannulated during percutaneous attempts to implant a permanent pacemaker in one and catheterize the subclavian vein in the other. Because both patients had serious comorbidities, endovascular repair of the subclavian perforations was performed using the Hemobahn endograft, a nitinol stent covered internally with expanded polytetrafluoroethylene. The endoprostheses were successfully deployed via an ipsilateral brachial artery access. No signs of endograft occlusion, migration, deformation, or fracture have been observed during follow-up at 12 and 10 months, respectively, in these patients. Conclusions: The Hemobahn stent-graft appears well suited to repairing subclavian artery injuries. Longer follow-up will determine if the design of this endograft will resist compression in this vascular location.
Pseudoaneurysm and Aortobronchial Fistula after Surgical Bypass for Aortic Coarctation: Management with Endovascular Stent-Graft
Authors: Smayra Tarek , Otal Philippe , Soula Pierre , Chabbert Valérie , Cérène Alain , Joffre Francis , Rousseau Hervé 
Published: March 2015

Purpose: To report the endovascular repair of an aortobronchial fistula at the distal anastomosis of a complex thoracic graft. Case Report: A 61-year-old man operated 18 years prior for aortic coarctation presented with hemoptysis. An aortobronchial fistula was suspected, but spiral computed tomography and angiography showed only a small pseudoaneurysm at the distal anastomosis without revealing the fistulous tract. A Talent stent-graft was successfully deployed through a femoral access, but the large delivery system injured the external iliac artery, producing a retroperitoneal hemorrhage. Prompt balloon occlusion of the aorta and subsequent bypass graft repair of the arterial injury prevented serious sequelae. The patient recovered without further complications. Follow-up imaging to 2 years has documented exclusion of the pseudoaneurysm with no hemoptysis or signs of new false aneurysm formation. Conclusions: Endovascular exclusion of anastomotic pseudoaneurysms even in complicated cases can be an efficient treatment option, but the procedure must be carefully planned and executed in order to achieve good results.
Heme Oxygenase-1 Gene Promoter Microsatellite Polymorphism is Associated with Restenosis after Percutaneous Transluminal Angioplasty
Authors: Exner Markus , Schillinger Martin , Minar Erich , Mlekusch Wolfgang , Schlerka Gerald , Haumer Markus , Mannhalter Christine , Wagner Oswald 
Published: March 2015

Purpose: To determine if an association exists between postdilation restenosis and heme oxygenase-1 (HO-1), which is induced by balloon injury and inhibits neointimal formation through the action of endogenous carbon monoxide. A dinucleotide repeat in the promoter region of the HO-1 gene shows a length polymorphism that modulates the level of gene transcription. Methods: This cohort study included 96 consecutive patients (64 men; median age 69 years, interquartile range 60–75) who underwent successful balloon dilation in the femoropopliteal segment. Six-month patency was evaluated using oscillography, ankle-brachial index, and duplex sonography. The association of patency and the length of (GT) repeats in the HO-1 gene promoter was assessed in univariate and multivariate analyses. Results: Restenosis was found in 23 (24%) patients within the first 6 months. Patients with short (<25 GT) dinucleotide repeats in the HO-1 gene promoter on either allele had restenosis significantly less often than patients with longer (≥25 GT) dinucleotide repeats (p = 0.01). Multivariate analysis revealed a significantly reduced risk for restenosis in these patients compared to patients without the short allele (odds ratio 0.2, 95% CI 0.06 to 0.70, p = 0.007). Conclusions: Genetic risk factors for restenosis after percutaneous transluminal angioplasty have not been investigated. In this patient population, short repeat alleles of the heme oxygenase-1 gene promoter polymorphism were associated with reduced postdilation restenosis at 6 months. Upregulation of HO-1 may be an important protective factor after balloon angioplasty by inhibition of vascular smooth muscle cell proliferation.
Unusual Case of AneuRx Stent-Graft Failure Two Years after AAA Exclusion
Authors: Krajcer Zvonimir , Howell Marcus , Dougherty Kathy 
Published: March 2015

Purpose: To present a case of type-III endoleak due to separation of modular components and suture breakage after abdominal aortic aneurysm (AAA) repair with the AneuRx stent-graft. Case Report: A 58-year-old man with a 78-mm AAA underwent successful aneurysm exclusion with an AneuRx stent-graft in 1998. Because the bifurcated component migrated during deployment, an additional aortic cuff was deployed to extend the stent-graft proximally to just below the renal arteries. On routine evaluation with computed tomography at 2 years postimplantation, a type-III endoleak with anterior displacement of the stent-graft was discovered. Angiography revealed separation of the aortic cuff from the stent-graft body. The aneurysm, which had decreased to 70 mm at 6 months, had enlarged to 80 mm in diameter. The patient underwent surgical AAA repair with removal of the stent-graft. Macroscopic examination showed suture breakage and separation of the stent rings and the graft material. Conclusions: This late complication of the AneuRx endograft underscores the need for frequent imaging surveillance in all patients undergoing endoluminal AAA repair.
Restenosis after Percutaneous Transluminal Angioplasty in the Femoropopliteal Segment: The Role of Inflammation
Authors: Schillinger Martin , Haumer Markus , Schlerka Gerald , Mlekusch Wolfgang , Exner Markus , Ahmadi Ramazanali , Minar Erich 
Published: March 2015

Purpose: To determine the value of baseline C-reactive protein (CPR), fibrinogen, and white blood cell (WBC) counts in predicting 1-year patency after percutaneous transluminal angioplasty (PTA) in the femoropopliteal segment. Methods: In a retrospective cohort study, 168 consecutive patients (103 men; median age 70 years, interquartile range 61–77) who underwent successful PTA of the femoral and/or popliteal arteries were analyzed. Twelve-month patency was evaluated using oscillography, ankle brachial index, duplex sonography, and angiography. The predictive value of inflammatory markers was assessed in a multivariate model controlling for cardiovascular risk factors, technical success, and hemodynamic factors. Results: Transient WBC elevation was found 6 hours after PTA, but this returned to baseline after 24 hours. Fibrinogen was elevated at 24 hours. Duplex scanning disclosed restenosis in 66 (39%) patients within the first 12 months after PTA. Only residual postdilation stenosis (≥30%) in the target segment (odds ratio 3.6, p=0.001) and baseline CRP levels (odds ratio 4.2, p=0.02) were independent predictors of outcome; neither WBC counts nor fibrinogen levels at any time point was associated with restenosis. Conclusions: Primary technical success and postinterventional hemodynamic flow at the dilated segment seem to be more important for intermediate-term patency than atherogenic risk factors. The predictive value of preprocedural serum CRP levels on restenosis should be further investigated.
Congenital Vascular Malformations in the Hand and Forearm
Authors: Sofocleous Constantinos T. , Rosen Robert J. , Raskin Keith , Fioole Bram , Hofstee Dirk-John 
Published: March 2015

Purpose: To review a single-center experience in the management of symptomatic congenital vascular malformations of the hand and forearm with special attention to embolotherapy. Methods: A retrospective chart review was performed to identify patients with vascular malformations referred for arteriography and possible intervention between 1983 and 1998. Arteriography and venography were performed in all patients to differentiate between true high-flow arteriovenous malformations (AVM) and low-flow primary venous malformations (PVM). The clinical and radiological data, procedural results, and follow-up data were retrieved and reviewed. Results: In a 15-year period, 39 patients (22 men; mean age 22.5 years, range 1–51) had symptomatic vascular lesions diagnosed in the forearm and hand: 21 AVMs, 17 PVMs, and one complex lesion with both AVM and PVM. Thirty-four (87%) lesions were treated with immediate technical success achieved in 31 (91%) cases; 5 (13%) lesions were not amenable to percutaneous treatment. There were no major complications, but 3 embolized AVMs had significant residual flow (81.6% technical success on intention to treat basis). Long-term follow-up ranging to 5 years was available in 26 of the 34 treated patients; the mean symptom-free period was 30 months for the AVM patients and 30.5 months for the PVM group, with an average of 1.5 and 1.2 embolization procedures, respectively. Conclusions: Vascular malformations of the hand and forearm are extremely rare lesions that demand a multidisciplinary approach for optimal diagnosis and management. Microembolotherapy with or without surgery has offered the highest level of safety and success to date.
Successful Stent-Graft Repair of a Vertebrojugular Arteriovenous Fistula
Authors: Rückert Ralph I. , Rutsch Wolfgang , Filimonow Sergej , Lehmann Rüdiger 
Published: March 2015

Purpose: To describe an apparently unreported endovascular means of treating a vertebral arteriovenous fistula (AVF) using a small-caliber stent-graft to permanently reconstruct the involved vessels. Case Report: A 13-year-old girl presented with tinnitus caused by a high-flow AVF between the right extracranial vertebral artery and deep jugular vein arising from repeated internal jugular vein catheterization. A 4-mm-diameter balloon-expandable Jostent coronary stent-graft was placed in the vertebral artery via a percutaneous femoral access, with immediate and complete obliteration of the AVF and resolution of the tinnitus. Follow-up duplex ultrasonography at 15 months demonstrated patency and luminal integrity of the vertebral artery. Conclusions: Vertebrojugular AVFs are rare and usually treated with transcatheter embolization techniques, but percutaneous repair using a small-caliber stent-graft appears feasible. This minimally invasive treatment might become the method of choice for AVFs in other small-bore vessels.
Type-II Endoleaks following Endovascular AAA Repair: Preoperative Predictors and Long-term Effects
Authors: Arko Frank R. , Rubin Geoffrey D. , Johnson Bonnie L. , Hill Bradley B. , Fogarty Thomas J. , Zarins Christopher K. 
Published: March 2015

Purpose: To determine the significance of persistent type-II endoleaks and whether they can be predicted preoperatively in patients with abdominal aortic aneurysms (AAA). Methods: The charts of all AAA patients treated with the AneuRx stent-graft at a single center from 1996 to 1998 were reviewed. Patients with <12-month follow-up or type-I endoleaks were excluded. The presence or absence of type-II endoleaks was determined from duplex imaging and computed tomographic angiography. Three groups were identified and compared: 16 patients with persistent type-II endoleaks (PE), 14 patients with transient type-II endoleaks (TE), and 16 patients with no endoleak (NE). Results: The groups did not differ with regard to age, preoperative comorbidities, follow-up time, and AAA neck diameter and length. AAA diameters were 57.1 ± 9.0 mm for NE, 63.4 ± 11.4 mm for TE, and 55.6 ± 4.2 mm for PE. The inferior mesenteric artery (IMA) was patent in 5 (31%) NE patients, 6 (43%) TE patients, and 13 (81%) PE patients (p < 0.01). The number of patent lumbar arteries visualized preoperatively was 0.5 ± 1.0 in NE, 1.3 ± 0.8 in TE, and 2.4 ± 0.6 in PE (p < 0.0001). Patent IMAs (RR 0.82, p<0.01) and >2 lumbar arteries (RR 0.40, p < 0.0001) were identified as independent preoperative risk factors for persistent endoleaks. There were no changes in mean diameter or volume in aneurysms with persistent endoleaks. Conclusions: No adverse clinical events were related to the presence of type-II endoleaks, but there was no decrease in aneurysm size in patients with persistent type-II leaks. Patients with a large, patent IMA, or >2 lumbar arteries on preoperative CT angiography are at higher risk for persistent type-II endoleaks.
Risk Stratification for Subclavian Artery Angioplasty: Is There an Increased Rate of Restenosis after Stent Implantation?
Authors: Schillinger Martin , Haumer Markus , Schillinger Sabine , Ahmadi Ramazanali , Minar Erich 
Published: March 2015

Purpose: To compare long-term patency after balloon angioplasty of stenotic or occluded subclavian arteries with and without adjunctive stenting and to identify independent risk factors for restenosis after balloon angioplasty. Methods: In a retrospective cohort study, 115 consecutive patients (65 women; mean age 60 years, interquartile range 53–68) who underwent PTA for atherosclerotic subclavian artery obstruction within a 15-year period were included. Among these, 26 (23%) consecutive patients had Palmaz stents routinely implanted since 1996. Follow-up investigation was performed in the year 2000. Patency during the median 44-month follow-up period (interquartile range 18–69 months, minimum 12) was evaluated by oscillography, blood pressure measurement, and color-coded duplex sonography. The predictive value of possible risk factors for restenosis was assessed in a multivariate model controlling for cardiovascular comorbidities and angiographic data. Results: PTA success was achieved in 98 (85%) patients, 72 (81%) of 89 undergoing angioplasty alone and all 26 with stents. Complete occlusion of the vessel and long lesions (≥2 cm) correlated with a lower success rate. One-year patency was 76% in unstented arteries and 95% in stented lesions due to better primary technical success, but at 4 years, the patency rates were 59% in arteries with stents and 68% in arteries without. Long lesions, residual stenosis after PTA, and stent implantation were independent predictors for restenosis after successful intervention. Conclusions: Subclavian arterial stent implantation is associated with better 1-year patency than PTA due to improved technical success, but intermediate and long-term outcomes are less favorable, as instent restenosis frequently occurs.
Overlapping Stents for Treatment of a Dissecting Carotid Artery Aneurysm
Authors: Benndorf Goetz , Campi Adriana , Schneider Gerd Helge , Wellnhofer Ernst , Unterberg Andreas 
Published: March 2015

Purpose: To report the increased efficacy of oversized, overlapping stents to treat an internal carotid artery (ICA) dissecting aneurysm. Case Report: A 55-year-old woman presented with reduced consciousness, aphasia, and right-sided hemiplegia owing to an infarction of the left middle cerebral artery territory documented by computed tomography. Digital subtraction angiography disclosed an extracranial dissection of the left ICA with a pseudoaneurysm. Two self-expanding Wallstents were placed, bridging the dissected segment and overlapping at the level of the aneurysm neck. Immediate arteriography showed remarkably reduced filling of the pseudoaneurysm. Serial arteriograms performed 6 days and 9 and 20 months after stenting documented the disappearance of the pseudoaneurysm without appreciable intimal hyperplasia of the vessel wall. Conclusions: Reducing stent porosity by overlapping the devices causes significant hemodynamic changes inside the aneurysm sac, accelerating intra-aneurysmal thrombosis.
Catheter Modification for Easier Cannulation of the Carotid Artery during Angioplasty and Stenting
Authors: Houdart Emmanuel , Mounayer Charbel , Chapot René , Saint-Maurice Jean-Pierre , Merland Jean-Jacques 
Published: March 2015

Purpose: To present a modification of both the guiding catheter and stent delivery system to facilitate access into sharply curved supra-aortic vessels during carotid angioplasty. Technique: Access failures during carotid interventions typically occur because either the vessel origin is acutely angled or the stenosis is located proximal to the carotid bifurcation, limiting access to the external carotid artery. We directly catheterized the left common carotid artery or brachiocephalic trunk with a guiding catheter whose tip had been curved by steam-shaping. The tip of the stent delivery system also was molded into a curve by this process so it engaged the curved part of the guiding catheter without pulling it out of the vessel. Conclusions: This simple modification can improve the success rate of carotid cannulation via the femoral approach and does not seem to increase the risk of the intervention.
Intrarenal Color Duplex Examination of Aortic Endograft Patients with Suprarenal Stents
Authors: Kalliafas Stavros , Travis Simon J. , Macierewicz Jan , Yusuf Syed W. , Whitaker Simon C. , Davidson Ian , Hopkinson Brian R. 
Published: March 2015

Purpose: To report an experience using intrarenal color duplex ultrasonography (ICDU) to detect high-grade renal artery stenosis in patients who had endovascular repair of abdominal aortic aneurysm (AAA) with suprarenal stent fixation. Methods: Twenty-eight patients (25 men; mean age 71 years, range 58–83) who had endovascular AAA repair with suprarenal stenting at least 3 months prior to commencement of this study were screened with ICDU. Acceleration time (AT), peak systolic velocity (PSV), end diastolic velocity (EDV), and resistive index (RI) were measured. The Doppler waveform was quantitatively scored on a scale from 0 to 4. AT >0.07 seconds, RI <0.45, or a Doppler waveform score of 0 or 1 (indicating loss of early systolic peak) were indicative of high-grade renal artery stenosis. Results: Median follow-up was 15.5 months (range 3–34). ICDU was successful in 54 (98%) of 55 kidneys scanned. No AT values exceeded 0.07 seconds, all RIs were >0.45, and no waveforms had loss of early systolic peak, indicating that no patient had evidence of high-grade renal artery stenosis. Conclusions: ICDU is a simple and affordable method that seems well suited to periodic screening in patients with suprarenal stents. Longer follow-up with a larger number of patients is needed before definite conclusions can be drawn about the effect of suprarenal stenting on renal circulation.
Repair of Secondary Aortoesophageal Fistula by Endoluminal Stent-Grafting
Authors: Bond Stephen E. , McGuinness Catharine L. , Reidy John F. , Taylor Peter R. 
Published: March 2015

Purpose: To describe a case of secondary aortoesophageal fistula that was treated with an endoluminal stent-graft. Case Report: A 58-year-old woman presented with hematemesis and melena. In 1974 she had an interposition graft repair of an aortic transection sustained during a traffic accident. At the examination in 1998, angiography demonstrated a mechanical disruption of the proximal anastomosis forming an aortoesophageal fistula. A 28-mm × 3.75-cm AneuRx stent-graft was introduced via a right femoral arteriotomy and deployed across the defect. Follow-up CT scans at 18 months showed exclusion of the false aneurysm with no evidence of infection; the patient remains well at >2 years after stent-graft implantation. Conclusions: Endoluminal repair can be successful in achieving a satisfactory midterm outcome in cases of secondary aortoesophageal fistula.