ABSTRACT
Acute ischemic stroke (AIS) is the leading cause of mortality and disability worldwide. AIS occur while cerebral arteries become blocked by embolism or thrombosis. Aspiration thrombectomy is a promising interventional device to extract massive clots from occluded cerebral arteries. The aim of this article is to develop a computer-aided method to clarify the performance of aspiration catheter and identify the risks of aspiration for each specific AIS patient. In order to simulate the aspiration process, a three-dimensional fluid-structure interaction (FSI) method was developed. The blood clot was modeled as a porous media which composed of viscoelastic fibrin networks. The finite element method (FEM) was implemented to compute the blood flow dynamics in the simplified cerebral vessel. The introduced clot model was validated by comparing the numerical results with experimental data. Furthermore, the analytical solution of the flow through the partially porous pipe was considered to validate FEM. In this research, the performance of two model of the Penumbra aspiration catheter-4MAX and 5MAX-were were compared at three distinct suction pressures. The aspiration ratio of the clot, aspiration time, amount of free fragments, wall shear stress (WSS), and extracted volume of the blood were calculated to evaluate catheters performance. At suction pressure -50 kPa, the aspiration ratio of 5MAX catheter reached 86.58% within 1.36 s. However, in 4MAX case, aspiration ratio of 76.41% was achieved within 1.39. Also, 5MAX catheter created 6.11% fewer free fragments in comparison to 4MAX. Hence, the possibility of distal embolization of 4MAX model was greater. However, the risk of vessel wall rupture was higher in 5MAX by considering mean WSS.
Subject(s)
Models, Cardiovascular , Thrombectomy , HumansABSTRACT
BACKGROUND: Despite the crucial role of referees in a soccer match, few researchers have targeted the injury profile of referees in their studies. Understanding the incidence, nature, and pattern of injuries could provide important information for educational and preventative efforts at the international level. HYPOTHESIS: The incidence rate and patterns of acute injuries to official referees of the Iranian Premier Football League during the 2009-2010 season are similar to those reported among referees in short-term international competitions such as FIFA World Cup. STUDY DESIGN: Prospective cohort study. METHODS: Demographic data for 74 referees, including 30 main referees and 44 assistant referees, were collected at the beginning of the season. To record injuries and refereeing time, weekly contact was made by a physician. RESULTS: In total, 102 injuries were reported by referees during the football season. The incidence rates of injuries among referees during training and matches were 4.6 and 19.6 injuries per 1000 hours, respectively. Muscular and tendon injuries were found to be the most common type of injury, and the most common site of injury was the lower leg followed by the hip and groin. CONCLUSION: The results of this study are consistent with similar prospective studies evaluating injuries to referees over the course of a short-term tournament. CLINICAL RELEVANCE: These findings provide a base for suggesting possible preventive recommendations in future studies.
