Surgical Resection and Histopathological Analysis of a Thrombosed Giant Fusiform MCA Aneurysm after Initial Treatment with a Flow Diversion Construct

• Published in: World neurosurgery 2017-07, Vol.103, p.348-354
• Main Authors: Sack, Jayson, MD, Cheung, Vincent, MD, Amaro, Deirdre, MD, Wali, Arvin R., BA, Santiago-Dieppa, David R., MD, Pannell, J. Scott, MD, Khalessi, Alexander A., MD, MS, FAHA, FAANS
• Format: Article
• Language: English
• Subjects: Aged; Embolization, Therapeutic - instrumentation; Encephaloduroarteriosynangiosis; Endovascular Procedures; Female; Fusiform giant MCA aneurysm; Graft Occlusion, Vascular - etiology; Graft Occlusion, Vascular - surgery; Humans; Indirect bypass; Intracranial Aneurysm - surgery; Neurosurgery; Open surgical aneurysm management; Pipeline reconstruction; Pipeline thrombosis; Postoperative Complications - etiology; Postoperative Complications - surgery; Stents; Stroke - etiology; Thrombosis - surgery; Treatment Outcome; Vascular Calcification - surgery
• ISSN: 1878-8750; 1878-8769
• DOI: 10.1016/j.wneu.2017.04.070

Abstract Background We describe the histopathology of an un-ruptured, giant calcified left MCA fusiform aneurysm initially treated with endovascular flow diversion. The flow diversion construct underwent post-operative in-stent thrombosis, necessitating surgical resection of the aneurysm to eliminate mass effect. Methods A 75-year-old woman with a known left MCA aneurysm presented to the Emergency Department with moderate right hemibody weakness. Due to the clinical and radiographic progression of the aneurysm, the patient was offered treatment. The patient was initially offered open surgical management of the lesion, but declined it—indicating that she would only consider endovascular treatment. The patient underwent endovascular reconstruction of the aneurysmal segment with an overlapping pipeline construct. Postoperatively, the patient experienced in-stent thrombosis of the pipeline construct. The thrombosed aneurysm exerted progressive local mass effect necessitating en bloc surgical resection of the aneurysm and stent construct. The aneurysm was submitted for pathologic analysis, which demonstrated chronologically older thrombus outside the flow diversion construct. Results Post-surgical imaging demonstrated a left MCA territory stroke. The patient gradually improved strength in her right hemibody. The histopathological analysis indicated that the degree of platelet activation and clot formation in this case was dependent upon the aggregate of surface area of thrombus and surface area pipeline device used in the reconstruction. Conclusion This technical report with histopathological analysis provides useful insights into the mechanism of aneurysmal thrombosis after flow diversion. It additionally raises new questions about the roles of thrombus formation, platelet aggregation, and stent-construct surface area in the maintenance of vessel patency.