Alicia A Ruthrauff1, Martin W King2, Gilles Soulez3, Kong T Tan4, Sean A Crawford5, Graham Roche-Nagle6, Guy Cloutier7, Leonard W Tse8. 1. College of Textiles, North Carolina State University, Raleigh, North Carolina. 2. College of Textiles, North Carolina State University, Raleigh, North Carolina; College of Textiles, Donghua University, Shanghai, China. 3. Department of Radiology, Centre Hospitalier de l'Université de Montréal Research Centre, Montreal, Quebec, Canada; Department of Radiology, Radio-oncology, and Nuclear Medicine, University of Montreal, Montreal, Quebec, Canada. 4. Division of Vascular and Interventional Radiology, Peter Munk Cardiac Centre, University Health Network, E6-220, Toronto General Hospital, University of Toronto, 200 Elizabeth Street, Toronto, Ontario M5G 2C4, Canada. 5. Joint Department of Medical Imaging, and Division of Vascular Surgery, Peter Munk Cardiac Centre, University Health Network, E6-220, Toronto General Hospital, University of Toronto, 200 Elizabeth Street, Toronto, Ontario M5G 2C4, Canada. 6. Department of Radiology, Radio-oncology, and Nuclear Medicine, University of Montreal, Montreal, Quebec, Canada; Institute of Biomedical Engineering, University of Montreal, Montreal, Quebec, Canada; Joint Department of Medical Imaging, and Division of Vascular Surgery, Peter Munk Cardiac Centre, University Health Network, E6-220, Toronto General Hospital, University of Toronto, 200 Elizabeth Street, Toronto, Ontario M5G 2C4, Canada. 7. Centre Hospitalier de l'Université de Montréal Hôpital Notre-Dame, and Laboratory of Biorheology and Medical Ultrasonics, Centre Hospitalier de l'Université de Montréal Research Centre, Montreal, Quebec, Canada. 8. Joint Department of Medical Imaging, and Division of Vascular Surgery, Peter Munk Cardiac Centre, University Health Network, E6-220, Toronto General Hospital, University of Toronto, 200 Elizabeth Street, Toronto, Ontario M5G 2C4, Canada. Electronic address: leonard.tse@utoronto.ca.
Abstract
PURPOSE: To evaluate the effects of in situ fenestration on the fabric of stent grafts deployed in a patient-specific phantom of a juxtarenal abdominal aortic aneurysm. MATERIALS AND METHODS: Four patient-specific juxtarenal abdominal aortic aneurysm polyurethane models were created, and bifurcated Zenith (Cook, Inc, Bloomington, Indiana) and Endurant (Medtronic, Minneapolis, Minneapolis) endografts were deployed into the models, covering the renal arteries. Antegrade in situ fenestration was carried out with radiofrequency puncture followed by balloon dilation with either conventional or cutting balloons. Renal covered stents were deployed and flared. Specimens were mounted onto an accelerated fatigue tester for 40M cycles (1 patient life-year), and evaluated with microscopy, caliper measurements, and fabric counts. RESULTS: Cutting balloons resulted in more fabric fraying. None of the fenestrations grew beyond the targeted 6-mm diameter despite accelerated fatigue. Fluoroscopic images demonstrated a very prominent waist of the renal fenestration in the Cook device when a conventional balloon was used compared with a cutting balloon. The average fenestration diameter for the Cook device was only 3.1 mm with the conventional balloon compared with 4.8 mm with the cutting balloon. The average fenestration diameter for the Medtronic device was 3.8 mm with the conventional balloon compared with 5.1 mm with the cutting balloon. The fabric counts suggested crowding of yarns around the fenestrations with conventional balloons but less with cutting balloons. CONCLUSIONS: This experimental work suggests that the size of in situ renal fenestrations does not expand beyond the target diameter despite cyclic fatigue. Although the small number of devices tested and selected aortorenal anatomy in this study may limit conclusions, textile analysis suggests that cutting balloons should be used for the Cook Zenith device, whereas conventional balloons should be used for the Medtronic Endurant device when performing in situ fenestration.
PURPOSE: To evaluate the effects of in situ fenestration on the fabric of stent grafts deployed in a patient-specific phantom of a juxtarenal abdominal aortic aneurysm. MATERIALS AND METHODS: Four patient-specific juxtarenal abdominal aortic aneurysm polyurethane models were created, and bifurcated Zenith (Cook, Inc, Bloomington, Indiana) and Endurant (Medtronic, Minneapolis, Minneapolis) endografts were deployed into the models, covering the renal arteries. Antegrade in situ fenestration was carried out with radiofrequency puncture followed by balloon dilation with either conventional or cutting balloons. Renal covered stents were deployed and flared. Specimens were mounted onto an accelerated fatigue tester for 40M cycles (1 patient life-year), and evaluated with microscopy, caliper measurements, and fabric counts. RESULTS: Cutting balloons resulted in more fabric fraying. None of the fenestrations grew beyond the targeted 6-mm diameter despite accelerated fatigue. Fluoroscopic images demonstrated a very prominent waist of the renal fenestration in the Cook device when a conventional balloon was used compared with a cutting balloon. The average fenestration diameter for the Cook device was only 3.1 mm with the conventional balloon compared with 4.8 mm with the cutting balloon. The average fenestration diameter for the Medtronic device was 3.8 mm with the conventional balloon compared with 5.1 mm with the cutting balloon. The fabric counts suggested crowding of yarns around the fenestrations with conventional balloons but less with cutting balloons. CONCLUSIONS: This experimental work suggests that the size of in situ renal fenestrations does not expand beyond the target diameter despite cyclic fatigue. Although the small number of devices tested and selected aortorenal anatomy in this study may limit conclusions, textile analysis suggests that cutting balloons should be used for the Cook Zenith device, whereas conventional balloons should be used for the Medtronic Endurant device when performing in situ fenestration.