Ex Vivo Study of the Physical Effect of Coils on Pressure and Flow Dynamics in Experimental Aneurysms
Hans G. Boecher-Schwarz
,a,
Kurt Ringela,
Laszlo Kopacza,
Axel Heimanna and
Oliver Kempskia
a From the Departments of Neurosurgery (H.G.B.-S.) and Neuroradiology (K.R.), University Hospital, and the Institut of Neurosurgical Pathophysiology (L.K., A.H., O.K.), University of Mainz, Mainz, Germany.
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FIG 1. Schematic drawing of the experimental system. Systemic flow was obtained from a conventional peristaltic pump, and then four air chambers and one check valve were used to produce a nearly constant, laminar, and unidirectional flow. This flow was then superimposed with a pulsatile flow generated by an electronically controlled valve and a resistance system. Intraaneurysmal and systemic pressure were recorded online
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FIG 2. Intraaneurysmal and systemic pressure measurements (± standard error of mean) obtained before and after coiling. The amount and shape of the pressure waves were not significantly different before and after coil embolization. (x axis, each time interval = 10–1 s)
A, Circulating fluid, 0.9% saline.
B, Circulating fluid, heparinized blood.
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FIG 3. Aneurysmal pulsation measurements (± standard error of mean) obtained before and after coil embolization. (x axis, each time interval = 10–1 s)
A, After coiling and while circulating a 0.9% saline solution, a statistically significant (P = .022) reduction of wall displacement was observed
B, No statistically significant reduction was observed with blood.
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FIG 4. Wall displacement/pressure curves measured before and after coil embolization describe hysteresis loops. Wall displacement follows changes in pressure with delay (arrows).
A, Circulating fluid, 0.9% saline.
B, Circulating fluid, heparinized blood.
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FIG 5. Results of impact/force measurements obtained for all experiments after coiling and while circulating a 0.9% saline solution. After embolization, in two cases, an increase of impact of more than twice the original values was measured. (x axis, each time interval = 10–1 s; y axis, impact/force [F]; diastolic value of impact = 0%; sytolic peak value of impact before coiling = 100%)
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