ダビガトランとイダルシズマブで塞栓性脳梗塞予防と出血性合併症に対処した非弁膜症性心房細動を有する無症候性外傷性硬膜下血腫の1例

A Case of Successful Drug Management with Dabigatran and Idarucizumab to Address Embolic and Hemorrhagic Complications for Asymptomatic and Traumatic Subdural Hematoma with Non-valvular Atrial Fibrillation

Ⅰ．緒　　言

　非弁膜症性心房細動（non-valvular atrial fibrillation：NVAF）患者におけるdirect oral anticoagulants（DOAC）に関するrandomized controlled trial（RCT）において，塞栓性脳梗塞の予防効果はワルファリンと同等とされており，出血性合併症のリスクは減少すると報告されている^1,3,4,10)．これらのRCTを参考にして，脳卒中治療ガイドライン2015では，NVAFのある脳梗塞または一過性脳虚血発作の再発予防としてDOAC治療が推奨されている⁷⁾．しかしながら，いずれの抗凝固療法でも頭蓋内出血のリスクは存在し^1,3,4,10)，最近はDOAC内服中の外傷性頭蓋内出血の臨床経過も報告されている²⁾．今回，われわれは無症候性の亜急性期外傷性硬膜下血腫の保存的観察中におけるダビガトランによる塞栓性脳梗塞の予防，および頭蓋内出血増悪時においてダビガトラン中和剤のイダルシズマブが外科的治療に有効であった症例を報告する．

　A 93-year-old woman incurred a head bruise 5 days prior to presentation, and head CT revealed right subacute subdural hematoma. As she was on direct oral anti-coagulant（DOAC）treatment for non-valvular atrial fibrillation（NVAF), the DOAC administration was stopped temporarily to prevent an increase in the size of the hematoma. Dabigatran treatment was initiated after the confirmation of no change in hematoma size and the follow-up CT revealed a reduction in the hematoma. However, left upper limb paresis occurred on day 12 of dabigatran treatment and head CT revealed the onset of right chronic subdural hematoma. Emergency burr hole surgery was performed after intravenous administration of idarucizumab to neutralize the dabigatran. Her neurologic symptoms improved after the operation and no recurrence of subdural hematoma was observed even after dabigatran treatment was resumed. Dabigatran could be administered relatively safely, even for subacute intracranial hemorrhage complicated with NVAF, suggesting the possibility of the prevention of ischemic stroke. Moreover, even when intracranial hemorrhage recurred, the prompt neutralizing effect of idarucizumab, a dabigatran-specific neutralizing agent, was useful in the surgical intervention and perioperative management.