Computational hemodynamic analysis of bypass graft for patients with severe femoral periphheral arterial disease

Abstract

Peripheral arterial disease (PAD) is a condition in which narrowed arteries reduce blood flowtothearmsorlegs.Thismaycauselegpainwhenwalking(claudication)and othersymptoms.PADisusuallyasignofabuildupoffattydepositsinthearteries (atherosclerosis).Atherosclerosis causes narrowing of the arteries that can reduce blood flowinthelegsand,sometimes,thearms.Femoral-bypasssurgeriesareacommon modeoftreatmentforthosewhoaresufferingfromseverePAD.Neointimalhyperpla- sia (NIH) occurs when the innermost layer of arteries is abnormally thickened as a result ofinjuryorcertainmedicalprocedureslikebypasssurgeries.AsaresultofNIH,the blood vessels can re-narrow again, which is known as restenosis.Hence, in numerical studies, theimprovementofthesehemodynamicfactorshasbeenutilizedasanindi- catortoachievesuperiorgeometriesandhigherpatencyratesforbypassgrafts.This studyaimstoconductacomputationalanalysisofdistinctanatomicalandgeometrical characteristics of grafts to determine optimal graft features for femoral bypass surgery,sothatithelpsvascularsurgeonsplantheirsurgerytoachievemaximumfavorable outputfromtheprocedure.Tomimicthereal-lifescenarioofbloodflowingthrough thefemoralbypassgraftsandtoacquirethehemodynamicparametersandresulting mechanicalparameters,acomputationalfluiddynamics(CFD)systemhasbeenused throughoutthisdissertation.Clinicalimagingmodalitieshavebeenusedinthisstudy toattainthepatient-specificmodelsofarteriesforcomputationalanalysis,whichwere used to create virtual femoral bypass surgery models.Parameters like wall shear stress (WSS),timeaveragewallshearstress(TAWSS),oscillatoryshearindex(OSI),high oscillatory low magnitude shear (HOLMES), pressure drop, flow velocity, and average helicity have been measured to analyze the performance of the graft under different ge- ometrical and anatomical variation.Through the results obtained in this research thesis,it shows that computational fluid analysis can be used in the medical field to aid doctors withhelpfulinformationandhelpthemtoservetheirpatients.