Massive subarachnoid hemorrhage after implantation of flow-diverter stent: clinical case and literature review

The study objective is to present a clinical case of massive subarachnoid hemorrhage after flow-diverter stent implantation for giant aneurysm and to review the literature on complication rate after use of flow diverter devices. Materials and methods. Forty two patients with large and giant cerebral aneurysms underwent surgical treatment with the use of flow-diverter stents in the department of neurosurgery of the Interregional Clinical Diagnostic Center (Kazan) from 2010 to 2018. In 1 case, massive subarachnoid hemorrhage as a result of aneurysm rupture with fatal outcome developed on the day 4 postoperatively. Results. Causes of aneurysm rupture after the installation of flow-diverter stents are still poorly understood. Possible causes include redirection of blood flow towards the part of the aneurysm, that has not been earlier exposed to high blood pressure; release of a large amount of enzymes from the thrombus formed in the aneurysm, which results in inflammation in the vessel wall; mechanical impact of the forming thrombus on the thinned aneurysm wall; reperfusion syndrome caused by artery stenosis developed before surgery; and administration of antiplatelets. The data on their effectiveness remain controversial. We report a case of aneurysm rupture, which was not prevented by steroid and nonsteroidal anti-inflammatory therapy received by a patients during the postoperative period. Conclusion. Aneurysm rupture after flow diverter implantation remains unpredictable and threatening complication which requires maximum awareness. Further studies and recommendations are needed to prevent this complication.