Spiral Laminar Flow - SUPA
Spiral Laminar Flow - SUPA
Spiral Laminar Flow - SUPA
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<strong>Spiral</strong> <strong>Laminar</strong> <strong>Flow</strong>:A revolution in understanding?Reintroduction of natural blood flow:The rationale for an improved stent design
Leg ArterialDiseaseResults in:- Pain- Ulceration- Amputation
Understanding Arterial DiseaseArterial Blood <strong>Flow</strong>
Understanding Arterial DiseaseArterial Blood <strong>Flow</strong><strong>Spiral</strong> laminar flow
807060504030spiralnon-spiral<strong>Spiral</strong> flow in the Aorta (MRI)Computational Fluid Dynamics20100Minimal Moderate Severe
Leonardo da Vinci<strong>Spiral</strong>s in art: (1) thedrawings of Leonardo daVinci from Vindzone Libraryshowing spiral flows in theheart cavity.La Bockeria et al.European Journal Cardio-thoracic Surgery2006;295:S251 – S258
<strong>Spiral</strong> <strong>Flow</strong> Vascular Graft Trial• Modify existing bypass graft• Produce spiral flow• Implant• Does it work better?
<strong>Spiral</strong> Bypass GraftClinical TrialPost-op Angios40 patients– monitored with imagingUltrasound (3 months)OutflowProximalAnastomosisSLF GraftDistalAnastomosis<strong>Spiral</strong> <strong>Laminar</strong> <strong>Flow</strong> through Runoff (3months)
Further Developments:Peripheral Stent v BypassRecognition Endovascular more attractive than bypass:• Improved patency with self expanding stents• Better than Balloon Angioplasty (PTA) alone in more severedisease• Worse than surgical bypass in more severe disease!• Does not preclude surgery later…Trend to treat with stents and if fail, bypass in less severe disease.
<strong>Spiral</strong> <strong>Flow</strong> Stent• How well do peripheral vascular stentswork?2 year patency (bare stents) range:• 80% Iliac ( Pelvis)• 65% Femoro-popliteal (Thigh)• 30-40% Infra-popliteal (Calf)• Why does the treatment fail?
Turbulence = Stent failureTurbulence associated with:- Altered wall shear stress- Damage lining artery- Cellular response is to “heal” – intimal hyperplasia- Loss of stent patency
Turbulence = Stent failureNon <strong>Spiral</strong><strong>Spiral</strong><strong>Spiral</strong> shows 30 times less “near wall turbulence”
Pre-Clinical <strong>Spiral</strong> Stent StudiesSTENTSTENOSISBloodflowHistologysitesPrestenosis1 2PoststenosisAfter cuff50% stenosis induced byextremities of the cuff
<strong>Spiral</strong> StentResults -Downstream Disease Progression<strong>Spiral</strong>Control StentNon-spiralNon-spiral stent shows greater downstream intimal thickening
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