Thrombosis in Cerebral Aneurysms and the Computational Modeling Thereof: A Review

Abstract

Thrombosis is a condition closely related to cerebral aneurysms and controlled thrombosis is the main purpose of endovascular embolization treatment. The mechanisms governing thrombus initiation and evolution in cerebral aneurysms have not been fully elucidated and this presents challenges for interventional planning. Significant effort has been directed towards developing computational methods aimed at streamlining the interventional planning process for unruptured cerebral aneurysm treatment. Included in these methods are computational models of thrombus development following endovascular device placement. The main challenge with developing computational models for thrombosis in disease cases is that there exists a wide body of literature that addresses various aspects of the clotting process, but it may not be obvious what information is of direct consequence for what modeling purpose (e.g., for understanding the effect of endovascular therapies). The aim of this review is to present the information so it will be of benefit to the community attempting to model cerebral aneurysm thrombosis for interventional planning purposes, in a simplified yet appropriate manner. The paper begins by explaining current understanding of physiological coagulation and highlights the documented distinctions between the physiological process and cerebral aneurysm thrombosis. Clinical observations of thrombosis following endovascular device placement are then presented. This is followed by a section detailing the demands placed on computational models developed for interventional planning. Finally, existing computational models of thrombosis are presented. This last section begins with description and discussion of physiological computational clotting models, as they are of immense value in understanding how to construct a general computational model of clotting. This is then followed by a review of computational models of clotting in cerebral aneurysms, specifically. Even though some progress has been made towards computational predictions of thrombosis following device placement in cerebral aneurysms, many gaps still remain. Answering the key questions will require the combined efforts of the clinical, experimental and computational communities.

Stent Porosity Efficiency in Treating Wide-Neck Saccular Renal Artery Aneurysm

“…This findings proved that stent placement succeed in its purpose to block blood from entering and circulating inside the aneurysm. This results agreed with the statement by Ngoepe et al (2018), which stated that the purpose of stent placement is to alter the hemodynamic of the blood by reducing the flow in the aneurysm dome and redirecting it along the main artery vessel. Ngoepe et al (2018) also stated that a reduced flow inside the aneurysm sac will result in clot formation, which is the desirable condition for recovery of aneurysm.…”

“…This results agreed with the statement by Ngoepe et al (2018), which stated that the purpose of stent placement is to alter the hemodynamic of the blood by reducing the flow in the aneurysm dome and redirecting it along the main artery vessel. Ngoepe et al (2018) also stated that a reduced flow inside the aneurysm sac will result in clot formation, which is the desirable condition for recovery of aneurysm. Sisto et al (2015) stated the same point, in which the reduced intra-sac velocity will promote thrombus formation inside the aneurysm.…”

Predictive modelling of thrombus formation in diabetic retinal microaneurysms

“…Blood clots or thrombi have been detected in various types of aneurysms in the macro-scale, such as cerebral aneurysms [ 22 ], abdominal aortic aneurysms [ 23 , 24 ] and dissecting aortic aneurysms [ 25 ], where they can either degrade the vessel wall and thus accelerate aneurysm rupture or stabilize the aneurysm by reducing the wall shear stress. However, the role of thrombosis in MAs has not been studied due to the limited resolution ability of standard imaging techniques to determine MA thrombus presence.…”

Kinetics of the coagulation cascade including the contact activation system: sensitivity analysis and model reduction

“…As pointed out by Ngoepe et al (2018) thrombosis models should be sophisticated enough to provide precious clinical information with a reasonable computational cost. To tackle this challenge in the context of deviced-associated thrombosis, a reduced model for thrombin generation triggered by contact activation of factor XII is proposed.…”