E-007 flow feature of intracranial unruptured vertebro-basilar artery dissecting aneurysm –relation of configuration with thrombosis formation and growing dissection

Abstract

Introduction Intracranial vertebro-basilar artery dissecting aneurysm (iVBD) can be a cause of subarachnoid hemorrhage (SAH), posterior circulation ischemia or local symptoms such as headache. Patients of iVBD with SAH are usually treated with trapping by endovascular procedures or clipping, because re-bleeding of iVBD is fatal in acute stage. However, in terms of a treatment for unruptured iVBD, its proper strategy is still controversial. In general, conservative approaches have been suggested because unruptured iVBD doesn’t have an aggressive clinical course. But some cases have an aggressive and malignant course, especially cases with basilar artery (BA) dissection extending from vertebral artery (VA). Appropriate timing and strategy for BA dissection extending from VA are less well-established because the treatment is challenging. The purpose of this presentation is to evaluate the hemodynamic findings on each iVBD status by computational fluid dynamics (CFD) and relation of them with thrombosis formation and growing dissection. Materials and methods Five patients diagnosed with iVBD were analyzed each clinical course, configuration of dissecting aneurysm and flow features. All patients are unruptured, two had BA dissection extending from VA and three had no extension to BA. We analyzed their flow status using CFD technology. Results Our results demonstrated one possibility that the angle between bilateral VA and BA causes the high impingement on the wall of aneurysm where has high pressure and divergent WSS vector. It means blood flow is unstable. On the other hand, cases without dissection extending to BA had more moderate flow in the dilated part of dissection because dissecting aneurysm located on low-angle vessel. Illustrative case 76-year-old male had BA dissection extending from VA. His dissecting aneurysm had gradually expanding and growing thrombosis formation caused compression of the brainstem. We treat coil embolization for dilated portion of intracranial left VA and occlusion with vascular plugs on extracranial left VA. In half day, his symptoms had worsed than preoperative period because of brain infarction and compression to brainstem with partial thrombosis in dissecting aneurysm. His results on CFD analysis has demonstrated flow from bilateral VA went into the same part of dilated wall and in left VA there were high pressure and wide flow instability. Conclusion In the future, to establish the timing and treatment strategy for BA dissection extending from VA, we need to continue tracking aneurysm status and analyze flow condition at dissecting aneurysm with CFD technology. Disclosures N. Uemiya: None. S. Ishihara: None. S. Kohyama: None. F. Yamane: None. T. Ootsuka: None. K. Mizokami: None. H. Neki: None. J. Niimi: None. E. Tsukagoshi: None.