Temporal correlation between wall shear stress and in-stent stenosis after Wingspan stent in swine model.
OBJECTIVE
A recent randomized clinical trial on intracranial atherosclerosis was discontinued because of the higher frequency of stroke and death in the angioplasty and stent placement group than in the medical treatment group. An in-depth understanding of the relationship between biologic responses and flow dynamics is still required to identify the current limitations of intracranial stent placement.


METHODS
Five Wingspan stents were deployed in tapered swine ascending pharyngeal arteries. Temporal wall shear stress distributions and in-stent stenosis were evaluated at days 0, 7, 14, and 28 after stent placement. The physiologic role of wall shear stress was analyzed regarding its correlation with in-stent stenosis.


RESULTS
In-stent stenosis reached a peak of nearly 40% at day 14 and decreased mainly at the distal stent segment until day 28. The wall shear stress demonstrated a characteristic pattern with time on the basis of the in-stent stenosis change. The wall shear stress gradient increased from the proximal to distal segment until day 14. At day 28, the trend was reversed dramatically, decreasing from the proximal to the distal segment. A significant correlation between the in-stent stenosis growth until day 14 and low wall shear stress values just after stent placement was detected. In-stent stenosis regression between days 14 and 28 was also associated with the high wall shear stress values at day 14.


CONCLUSIONS
These data suggest that the physiologic wall shear stress can control the biphasic in-stent stenosis change in tapered arteries.
From the Division of Interventional Neuroradiology (M.F., H.T., Y.S., F.M., S.T., Y.M., F.V.), Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California moto.fujimo@gmail.com.
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Fujimoto
From the Division of Interventional Neuroradiology (M.F., H.T., Y.S., F.M., S.T., Y.M., F.V.), Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CaliforniaDepartment of Neurosurgery (H.T., T.S., Y.M.), Jikei University School of Medicine, Tokyo, Japan.
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Takao
Department of Neurosurgery (H.T., T.S., Y.M.), Jikei University School of Medicine, Tokyo, JapanDepartment of Mechanical Engineering (T.S., M.Y.), Graduate School of Engineering, Tokyo University of Science, Tokyo, Japan.
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Suzuki
From the Division of Interventional Neuroradiology (M.F., H.T., Y.S., F.M., S.T., Y.M., F.V.), Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California.
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Shobayashi
From the Division of Interventional Neuroradiology (M.F., H.T., Y.S., F.M., S.T., Y.M., F.V.), Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California.
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Mayor
From the Division of Interventional Neuroradiology (M.F., H.T., Y.S., F.M., S.T., Y.M., F.V.), Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California.
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Tateshima
Department of Mechanical Engineering (T.S., M.Y.), Graduate School of Engineering, Tokyo University of Science, Tokyo, Japan.
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Yamamoto
From the Division of Interventional Neuroradiology (M.F., H.T., Y.S., F.M., S.T., Y.M., F.V.), Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CaliforniaDepartment of Neurosurgery (H.T., T.S., Y.M.), Jikei University School of Medicine, Tokyo, Japan.
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Murayama
From the Division of Interventional Neuroradiology (M.F., H.T., Y.S., F.M., S.T., Y.M., F.V.), Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California.
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Viñuela
D000375:Aging; D000818:Animals; D001158:Arteries / Q000503:physiopathology* / Q000601:surgery*; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001807:Blood Vessel Prosthesis / Q000009:adverse effects; D003198:Computer Simulation; D004195:Disease Models, Animal; D019544:Equipment Failure Analysis; D006083:Graft Occlusion, Vascular / Q000209:etiology* / Q000503:physiopathology*; D008955:Models, Cardiovascular; D011474:Prosthesis Design; D033081:Shear Strength; D015607:Stents / Q000009:adverse effects*; D013314:Stress, Mechanical; D013552:Swine; D013997:Time Factors; D016896:Treatment Outcome