渡邊 亮司¹, 近藤 吉将¹, 中田 浪枝¹, 上原 貴秀^{2, 3}, 大本 昌樹^{2, 3}

Ryoji WATANABE¹, Yoshimasa KONDO¹, Namie NAKATA¹, Takahide UEHARA^{2, 3}, Masaki OOMOTO^{2, 3}

¹済生会今治病院検査部, ²済生会今治病院内科, ³済生会今治病院透析センター

¹Department of Clinical Laboratory, Saiseikai Imabari Hospital, ²Department of Internal Medicine, Saiseikai Imabari Hospital, ³Hemodialysis Treatment Center, Saiseikai Imabari Hospital

キーワード : vascular access, VA ultrasonography, stenosis, occlusion, brachial artery flow volume

慢性維持透析療法に必要なバスキュラーアクセス（vascular access: VA）は，VAエコーで評価が可能である．自己血管動静脈内シャント（arteriovenous fistula: AVF），人工血管内シャント（arteriovenous graft: AVG），動脈表在化についてのVAエコーによる狭窄・閉塞の評価について述べる．VAの狭窄，閉塞の評価はBモードにて，シャント血管の走行や病変部の性状など形態評価を行う． AVF，AVGについては，形態評価に加えてパルスドプラ法にて上腕動脈の血流波形から算出した1分間の血流量や血管抵抗指数（resistance index: RI）でシャントの機能的評価が可能であり，VAの機能的モニタリングの指標として，全例で測定する意義は大きい．AVFでは吻合部狭窄や静脈側（静脈弁の硬化も含む），ステント留置部に狭窄を起こす．閉塞症例では，血栓によるものが多いが，血栓形成の原因となる狭窄起点の同定が重要である．AVGにおけるVAエコーの形態的評価は，人工血管内に起こる狭窄・閉塞病変の評価，静脈側の流出路に好発する狭窄病変の評価を行う．動脈表在化の表在化部の脱血側穿刺部に狭窄を起こすことがある．また，血栓などにより閉塞を起こす場合がある．動脈表在化は，繰り返す穿刺により動脈壁の損傷による合併症が多く，VAエコーによる定期的な経過観察が重要である．

The vascular access (VA) necessary for chronic hemodialysis can be assessed using VA ultrasonography. We discuss the assessment of stenosis and occlusion of arteriovenous fistula (AVF), arteriovenous graft (AVG), and subcutaneously fixed superficial artery by VA ultrasonography. B-mode can be used to assess the shunt vessel course and properties of the involved area in VA stenosis and occlusion. In addition to morphological assessment, functional assessment of AVF and AVG is possible with pulsed Doppler by using flow volume (BA-FV) in 1 minute calculated based on the flow pattern of the brachial artery and the resistance index (RI), and measuring these is very useful as an indicator in the functional monitoring of VA in all cases. Anastomotic stricture and venous (including hardening of venous valve) and stent site stenosis occur in AVF. In cases with occlusion, it is often caused by a thrombus, but it is important to identify the origin of the stenosis that is causing thrombus formation. Morphological assessment of AVG using VA ultrasonography consists of assessment of stenosis and occlusion occurring in the graft and assessment of stenosis that tends to occur at the venous outflow tract. Stenosis can occur at the cannulation site of a subcutaneously fixed superficial artery. Occlusion can also occur due to a thrombus or other cause. Subcutaneously fixed superficial artery is often complicated by damage to the arterial wall due to repeated punctures, and regular follow-up observation with VA ultrasonography is important.