Development of a recalcitrant, large clot burden, bifurcation occlusion model for mechanical thrombectomy

Abstract

<jats:sec> <jats:title>OBJECTIVE</jats:title> <jats:p>Stroke is a major cause of disability and death in adults. Several large randomized clinical trials have shown the significant benefit of mechanical thrombectomy with modern stent retrievers in the treatment of large-vessel occlusions. However, large clots located at bifurcations remain challenging to treat. An in vivo model of these recalcitrant clots needs to be developed to test future generations of devices.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>Autologous blood was drawn from anesthetized swine via a femoral sheath. Blood was then mixed with thrombin, calcium chloride, and saline, and injected into silicone tubing to form cylindrical clots in the standard fashion. Matured clots were then delivered in an unfragmented fashion directly into the distal extracranial vasculature, at branch points where vessel sizes mimic the human middle cerebral artery, by using Penumbra aspiration tubing and the Penumbra ACE68 reperfusion catheter.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>A total of 5 adult swine were used to develop the model. The techniques evolved during experiments in the first 3 animals, and the last 2 were used to establish the final model. In these 2 swine, a total of 8 autologous clots, 15–20 mm, were injected directly into 8 distal extracranial vessels at branch points to mimic a bifurcation occlusion in a human. All clots were delivered directly at a distal bifurcation or trifurcation in an unfragmented fashion to cause an occlusion. Ten revascularization attempts were made, and none of the branch-point occlusions were fully revascularized on the first attempt.</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>Using novel large-bore distal access catheters, large unfragmented clots can be delivered into distal extracranial vessels in a swine occlusion model. The model mimics the clinical situation of a recalcitrant bifurcation occlusion and will be valuable in the study of next-generation stroke devices and in training settings.</jats:p></jats:sec>

Fast acquisition cone-beam computed tomography: initial experience with a 10 s protocol

“…The 10 s CBCT images provided enough spatial resolution and contrast resolution to assess the flow diverter structure, relationship to the aneurysm neck, and parent artery apposition. Similar findings have also been observed in imaging other devices such as stent retrievers 6. The contrast dose used in the 10 s protocol is nearly half that of the 20 s protocol (36 mL vs 66 mL) as the injection rate is the same between the two and time is reduced by 50%.…”

“…Both 10 s and 20 s protocols were acquired in a porcine model that underwent neurointervention under a protocol6 approved by the Institutional Animal Care and Use Committee. The experimental design was modeled after previous studies of CBCT 7.…”

Development and characterization of aptamer-conjugated imaging tools for diagnostic applications

“…Whole rat blood was clotted using a previously established thrombectomy protocol. 152 In brief, 1 mL of CaCl2-thrombin solution was prepared using 0. To determine whether FA binding to fibrin is selective, the observed differences in fluorescence were quantified using the ImageJ analysis program and compared ( Figure 3.1C).…”

“…150,151 However, any malfunction within the clotting cascade may lead to numerous thrombotic complications, resulting in hypercoagulation and vascular occlusions. 34,152,153 Stroke is an example of an acute vascular event in which fibrin can play a major role. therefore, not managed.…”

“…However, malfunctions, stemming from congenital disorders or a diverse group of clinical conditions, may lead to hypercoagulable states, which are highly undesirable. 31,34,35,152,205 Pathophysiology of thrombosis is the underlying cause of vascular disease states,…”