Non-Occluding Stent Graft Expansion
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UNL does not discriminate based on race, ethnicity, color, national origin, sex, religion, disability, age, sexual orientation, gender identity, genetic information, veteran status, marital status, and/or political affiliation in its programs, activities, or employment. © 2014 The Board of Regents of the University of Nebraska. All rights reserved. • The final design solution is a balloon similar in shape in size to balloons currently used, but features channels for blood to flow through. • The profile of the balloon involves a tapered end to direct blood flow into the channels and will be made of a non-compliant PET material to hold the shape and prevent closing of the channels. • The flow simulation conducted showed there is minimal flow reduction with this design, around 30% reduction in flow. • Due to the Venturi effect present in this flow simulation, an increase in velocity and decrease in pressure will occur, ensuring balloon form will remain constant. DESIGN SUMMARY DELIVERABLE REFERENCES • A detailed SolidWorks drawing that could be used as patent application art • A simple, 5 slide PowerPoint presentation describing and illustrating the clinical and engineering problems and our solution OBJECTIVE BACKGROUND • Aortic Aneurysms: abnormal widening of the aorta due to weakening of aortic wall. • In 2009, over 10,000 reported deaths were caused by aortic aneurysms in the US [1]. • Occur in both thoracic and abdominal aorta • Most common cause is atherosclerosis, or hardening of the artery so the vessel is less elastic [2]. • Leads to: o Aortic dissection: blood leaks out of inner aortic wall layer o Rupture: outer layer tears open • Current treatment: endovascular stent graft repair and balloon angioplasty o Stent graft materials: nitinol and Gore-Tex • Problems with current procedure: o Balloon completely blocks blood flow, which leads to a large spike in blood pressure [3]. o Improper positioning could result – average of 1.7 stents/patient o Higher restenosis rates [4]. Current expansion techniques are problematic, as they cause occlusion, or a blockage of blood flow at the expansion site, interrupting blood supply to the body. There is a need for a noninvasive mechanism that will successfully expand the implanted stent graft to the arterial wall with decreased occlusion of blood flow during the standard insertion procedure. PROBLEM CONSTRAINTS AND CRITERIA CONSTRAINT CRITERIA Non-occluding Less than 50% flow reduction distal to device with at least 2.5 L/min cardiac output flow Performs necessary function Successfully seals the implanted stent graft to the inner wall of the aorta [5] Biocompatible Made of materials known to be biocompatible and previously utilized in the medical field Compatible with current procedure Able to be inserted/removed via catheter into 6 mm femoral artery insertion [6] User feedback of attachment progress Surgeon can detect pressure of expansion device from arterial wall at about 10 atm [7] DECISION MATRIX Development of a Non-Occluding Stent Graft Expansion Device Group Ten: Christopher Davidson, Samantha Nelson, Jaideep Sahni, Halle Swann Clients: Jason MacTaggart, M.D. and Alexey Kamenskiy, Ph.D. - Faculty Managers: Nicole Iverson, Ph.D. and Angela Pannier, Ph.D. • To design a device that seals an implanted stent graft onto an adjacent wall of the aortic arch with less than 50% flow reduction distal to the device at any time during aortic aneurysm treatment. Figure 3: Dimetric view of catheter assembly with flow velocity projections. Figure 2: SolidWorks drawing of final balloon solution. Figure 4: Side view of catheter assembly with flow velocity projections. Figure 1: Schematic illustration of aortic aneurysm. Table 1: Constraints and Criteria Table 2: Potential Solution Decision Matrix (on a 310 scale) [1] Kochanek KD, Xu JQ, Murphy SL, Miniño AM, Kung HC. Deaths: final data for 2009. Natl Vital Stat Rep 2011;60(3). [2] Aortic Aneurysm Fact Sheet. Centers for Disease Control and Prevention. July 22, 2014. [3] Masson J, Kovac J, Schuler G et al. Transcatheter aortic valve implantation: Review of the nature, management, and avoidance of procedural complications. J Am Coll Cardiol Int 2009;2(9):811-820. [4] Schuster I, Dorfmeister M, Scheuter-Mlaker S, Gottardi R, Hoebartner M, Roedler S, et al. Endovascular and Conventional Treatment of Thoracic Aortic Aneurysms: A Comparison of Costs. Ann Thorac Surg 2009;87:1801-1805.e6. [5] Hamed Azarnoush. 2012. Modeling and Control of Angioplasty Balloon Deployment Based on Intravascular Optical Coherence Tomography. Ph.D. Dissertation. McGill University, Montreal, Que., Canada, Canada. Advisor(s) Benoit Boulet. AAINR79136. [6] Bhogal, Ricky Harminder, and Richard Downing. "The Evolution of Aortic Aneurysm Repair: Past Lessons and Future Directions." (2011): 21-54. [7] Babineau, Timothy J., et al. "The cost of operative training for surgical residents." Archives of surgery 139.4 (2004): 366-370.
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Transcript of Non-Occluding Stent Graft Expansion
UNLdoesnotdiscriminatebasedonrace,ethnicity,color,nationalorigin,sex,religion,disability,age,sexualorientation,genderidentity,geneticinformation,veteranstatus,maritalstatus,and/orpoliticalaffiliationinitsprograms,activities,oremployment.© 2014 The Board of Regents of the University of Nebraska. All rights reserved.
• Thefinaldesignsolutionisaballoonsimilarinshapeinsizetoballoonscurrentlyused,butfeatureschannelsforbloodtoflowthrough.
• Theprofileoftheballooninvolvesataperedendtodirectbloodflowintothechannelsandwillbemadeofanon-compliantPETmaterialtoholdtheshapeandpreventclosingofthechannels.
• Theflowsimulationconductedshowedthereisminimalflowreductionwiththisdesign,around30%reductioninflow.
• DuetotheVenturieffectpresentinthisflowsimulation,anincreaseinvelocityanddecreaseinpressurewilloccur,ensuringballoonformwillremainconstant.
DESIGN SUMMARY
DELIVERABLE
REFERENCES
• AdetailedSolidWorksdrawingthatcouldbeusedaspatentapplicationart
• Asimple,5slidePowerPointpresentationdescribingandillustratingtheclinicalandengineeringproblemsandoursolution
OBJECTIVEBACKGROUND
• AorticAneurysms:abnormalwideningoftheaortaduetoweakeningofaorticwall.
• In2009,over10,000reporteddeathswerecausedbyaorticaneurysmsintheUS[1].
• Occurinboththoracicandabdominalaorta• Mostcommoncauseisatherosclerosis,or
hardeningofthearterysothevesselislesselastic[2].
• Leadsto:o Aorticdissection:bloodleaksoutof
inneraorticwalllayero Rupture:outerlayertearsopen
• Currenttreatment:endovascularstentgraftrepairandballoonangioplasty
o Stentgraftmaterials:nitinolandGore-Tex
• Problemswithcurrentprocedure:o Ballooncompletelyblocksbloodflow,
whichleadstoalargespikeinbloodpressure[3].
o Improperpositioningcouldresult–averageof1.7stents/patient
o Higherrestenosisrates[4].
Currentexpansiontechniquesareproblematic,astheycauseocclusion,orablockageofbloodflowattheexpansionsite,interruptingbloodsupplytothebody.Thereisaneedforanoninvasivemechanismthatwillsuccessfullyexpandtheimplantedstentgrafttothearterialwallwithdecreasedocclusionofbloodflowduringthestandardinsertionprocedure.
PROBLEM
CONSTRAINTS AND CRITERIA
CONSTRAINT CRITERIA
Non-occludingLessthan50%flowreductiondistaltodevicewithatleast2.5
L/mincardiacoutputflow
Performsnecessaryfunction
Successfullysealstheimplantedstentgrafttotheinnerwallof
theaorta[5]
BiocompatibleMadeofmaterialsknowntobebiocompatibleandpreviouslyutilizedinthemedicalfield
Compatiblewithcurrentprocedure
Abletobeinserted/removedviacatheterinto6mmfemoral
arteryinsertion[6]
Userfeedbackofattachmentprogress
Surgeoncandetectpressureofexpansiondevicefromarterial
wallatabout10atm[7]
DECISION MATRIX
Development of a Non-Occluding Stent Graft Expansion DeviceGroup Ten: Christopher Davidson, Samantha Nelson, Jaideep Sahni, Halle Swann
Clients: Jason MacTaggart, M.D. and Alexey Kamenskiy, Ph.D. - Faculty Managers: Nicole Iverson, Ph.D. and Angela Pannier, Ph.D.
• Todesignadevicethatsealsanimplantedstentgraftontoanadjacentwalloftheaorticarchwithlessthan50%flowreductiondistaltothedeviceatanytimeduringaorticaneurysmtreatment.
Figure3:Dimetricviewofcatheterassemblywithflowvelocityprojections.
Figure2:SolidWorksdrawingoffinalballoonsolution.
Figure4:Sideviewofcatheterassemblywithflowvelocityprojections.
Figure1:Schematicillustrationofaorticaneurysm.
Table1:ConstraintsandCriteria
Table2:PotentialSolutionDecisionMatrix(ona310scale)
[1]KochanekKD,XuJQ,Murphy SL,MiniñoAM,KungHC.Deaths:finaldatafor2009.NatlVitalStatRep2011;60(3).[2]AorticAneurysm FactSheet.CentersforDiseaseControlandPrevention. July22,2014.[3]MassonJ,KovacJ,SchulerGetal.Transcatheteraorticvalveimplantation:Reviewofthenature,management,andavoidanceofprocedural complications.JAmCollCardiolInt2009;2(9):811-820.[4]Schuster I,DorfmeisterM,Scheuter-MlakerS,GottardiR,HoebartnerM,RoedlerS,etal.EndovascularandConventional TreatmentofThoracicAorticAneurysms:AComparisonofCosts.AnnThoracSurg2009;87:1801-1805.e6.[5]HamedAzarnoush.2012.ModelingandControlofAngioplastyBalloonDeploymentBasedonIntravascularOpticalCoherenceTomography.Ph.D.Dissertation.McGillUniversity,Montreal,Que.,Canada,Canada.Advisor(s) BenoitBoulet.AAINR79136.[6]Bhogal,RickyHarminder,andRichardDowning."TheEvolutionofAorticAneurysmRepair:PastLessonsandFutureDirections." (2011):21-54.[7]Babineau,TimothyJ.,etal."Thecostofoperative trainingfor surgicalresidents."Archivesofsurgery 139.4(2004):366-370.
