Microthrombi and hypercoagulability’s contribution to delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

Despite increasing knowledge over the last several decades of the factors contributing to delayed cerebral ischemia (DCI), it remains a significant cause of morbidity after aneurysmal subarachnoid hemorrhage (aSAH). The hypercoagulable state induced by aneurysm rupture is critical to most proposed mechanisms of DCI either through its direct contribution to microthrombi formation, or through the indirect effects of the products of coagulation on vasospasm, and inflammation. In this review we summarize clinical evidence of hypercoagulability after aSAH as well as both the clinical and pre-clinical evidence of its role in DCI, highlighting the role that microthrombi and NETosis are thought to play.