Changes in Wall Shear Stress of Cerebral Arteriovenous Malformation Feeder Arteries After Embolization and Surgery

Abstract

Background and Purpose— Wall shear stress (WSS) has been implicated as an important stimulus for vascular remodeling. The purpose of this study is to measure WSS in AVM arterial feeders using quantitative magnetic resonance angiography pre- and post-embolization/surgery. Methods— Records of patients who underwent AVM embolization and surgical resection at our institution between 2007 and 2013 and had WSS, flow rate, and vessel diameter obtained pre- and post-treatment using quantitative magnetic resonance angiography were retrospectively reviewed. WSS was compared between the feeder and contralateral artery pre- and post-embolization/surgery. Results— Twenty-one patients were included (mean age 34 years, 19% hemorrhagic presentation), with Spetzler–Martin grades 1 to 4. WSS, blood flow, and vessel diameter were assessed in a total of 51 feeder arteries. At baseline, mean WSS was significantly higher compared with the contralateral vessel (29.7±12.0 dynes/cm 2 versus 23.3±11.0 dynes/cm 2 ; P =0.007). After embolization (23.0 dynes/cm 2 versus 22.5 dynes/cm 2 ; P =0.78) and surgery (17.9 dynes/cm 2 versus 23.2 dynes/cm 2 ; P =0.09), WSS was not significantly different than in the contralateral vessel. Reduced WSS post-embolization corresponded to significantly decreased flow (338.1 mL/min versus 170.3 mL/min; P <0.001) and smaller vessel diameter (3.7 mm versus 3.5 mm; P =0.01). Conclusions— Enlargement of cerebral AVM arterial feeders is insufficient to compensate for increased blood flow, creating high WSS. After treatment, flow diminishes and so WSS and vessel diameter concomitantly decrease. Thus, WSS plays a pivotal role in vascular remodeling that may be exploited to monitor AVM response to treatment or understand other high-flow vascular pathologies.

Quantitative assessment of changes in hemodynamics of the internal carotid artery after bypass surgery for moyamoya disease

“…17 More recently, Alaraj et al demonstrated that WSS was a potential biomechanical factor for efficient treatment of arteriovenous malformations. 1 In the present study, the mean WSS of both surgical and nonsurgical ICAs decreased, with the difference in mean WSS between surgical and contralateral ICAs following surgery found to be not significant. Because multiple stenotic changes occur along the ICA, the mean WSS may not be a sensitive parameter in the measurement of hemodynamic changes following surgery for treatment of MMD.…”

Stable thrombus formation on irradiated microvascular endothelial cells under pulsatile flow: Pre-testing annexin V-thrombin conjugate for treatment of brain arteriovenous malformations

“…However, the system is limited with respect to achieving a completely physiological flow rate and shear stress level, which was limited by the ability of the endothelial cells to adhere to the artificial collagen substratum. Average WSS measurements lie in the range of 2 -67.4 dynes/cm 2 for the large cerebral feeder vessels of AVMs [37], and in the range of 7 -23 dynes/cm 2 for normal intracranial vessels [38]. The ability to culture human AVM endothelial cells isolated from surgically excised human AVMs would also be more physiologically relevant but we consider not necessary for early development and pre-testing of conjugate once a valid target is identified.…”

Risk factors for hemorrhage of brain arteriovenous malformation

“…Alternatively, we also have uncertainty of posttherapeutic ICH, such as after microsurgical, embolization, or gamma knife treatments . Demonstrating flow parameters preintervention that elevate posttreatment risk could help direct patients to alternative therapies and/or different postsurgical management . Research into both of these clinical scenarios has enlisted hemodynamic metrics to help explain such hemorrhagic episodes with varying degrees of success.…”