超音波検査技術

ISSN: 1881-4506
一般社団法人日本超音波検査学会
〒162-0801 東京都新宿区山吹町358-5
Japanese Journal of Medical Ultrasound Technology 43(1): 34-42 (2018)
doi:10.11272/jss.43.34

学術賞-研究Researcher's Award - Research Paper

バスキュラーアクセス超音波におけるAVF吻合部遠位の血流測定Investigation of Blood Flow Measurements Using Vascular Access Ultrasonography in the Anastomotic Distal Portion of an Arterio-venous Fistula

萬田記念病院放射線科Department of Radiology, Manda Memorial Hospital

受付日:2017年3月30日Received: March 30, 2017
受理日:2017年10月13日Accepted: October 13, 2017
発行日:2018年2月1日Published: February 1, 2018
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目的:超音波検査によるAVF(自己血管内シャント)吻合部以遠の血流観察の臨床的意義を検討した.

対象および方法:2014年5月~12月の間に定期的にバスキュラーアクセス超音波を行った38名(右前腕内シャント:3名 左前腕内シャント:35名)を対象に吻合部遠位部の血流方向と血流量を計測した.血流方向はカラードプラ法にて判定し,血流量はパルスドプラ法にて時間平均血流速度を用いて計測した.血流方向が遠位より吻合部方向はType 1, 吻合部より遠位方向はType 2とし,二つのTypeの上腕動脈,橈骨および尺骨動脈の血流量を定量的に比較した.さらに尺骨動脈/橈骨動脈の血流量比(U/R ratio)を計測しType間で比較した.シャント血管に狭窄(血管内径2 mm未満)や上腕動脈血流量が500 mL/min以下の症例は除外した.

結果:血流方向は,Type 1: 65.8%(25例),Type 2: 34.2%(13例),血流量はType 1: 126.1±114.9 mL/min, Type 2: 80.4±57.6 mL/minだった.上腕動脈,橈骨および尺骨動脈の血流量はType間に有意差はなかったが,U/R ratioは,Type 2(0.29±0.25)はType 1(0.44±0.22)に比べ有意に低かった(p=0.02).

考察:AVF吻合部以遠の血流方向は順方向と逆方向の二つのTypeを認めた.血流方向の決定因子は,尺骨動脈,橈骨動脈の血流量比と関連を示した.吻合部以遠が順方向血流の場合には,上腕動脈血流量とシャント血流量が近似値とならない可能性があるため,橈骨動脈血流量または尺骨動脈血流量を差分した上腕動脈血流量で評価することが適当と考えられた.

結論:バスキュラーアクセス超音波におけるAVF吻合部遠位血行動態の調査における臨床的意義については明確に示すものは認められなかった.しかし,我々は今回の検討で吻合部遠位の血流方向は尺骨動脈と橈骨動脈の血流量比が関与していることを示し,吻合部遠位が順方向血流の場合は上腕動脈血流量から推定するシャント血流量は補正が必要であることを提案した.

Purpose: We investigated the clinical significance of blood flow measurements using ultrasonography in the anastomotic distal portion of an arteriovenous fistula (AVF).

Methods and Materials: The study population comprised 38 hemodialysis patients (right shunt: 3 patients; left shunt: 35 patients) who underwent periodic vascular-access ultrasonography at our hospital between May 2014 and December 2014. Blood flow direction and volume at the anastomotic distal portion were measured. Blood flow direction was determined using the color Doppler technique, and the time-average flow rate was measured using the pulsed-wave Doppler technique. The direction from the distal to the anastomotic portion was defined as Type 1, and the direction from the anastomotic portion to the distal portion was defined as Type 2. Blood flow volume in the two types of brachial arteries and the radial and ulnar arteries was quantitatively compared. In addition, the ratio of blood flow volume in the ulnar to that in the radial arteries (ulnar/radial) was compared. Cases with severe stenosis (<2 mm) of lumen in the vascular access and those with a low brachial arterial blood flow volume (<500 mL/min) were excluded.

Results: Blood flow directions and volumes in the shunt anastomotic distal portion of the AVF were as follows: Type 1, 65.8% (25 cases) and 126.1±114.9 mL/min, and Type 2, 34.2% (13 cases) and 80.4±57.6 mL/min, respectively. No significant difference was observed between blood flow types, which in flow volume of the brachial artery, the radial artery, and the ulnar artery. The ulnar/radial blood flow volume ratio was significantly different between the two studied types (Type 1: 0.44±0.22; Type 2: 0.29±0.25; p=0.02). Steal syndrome was suspected in two cases.

Discussion: The hemodynamics of AVF revealed two types, and the blood flow directions were forward and opposite. The blood flow direction appeared to be related to the ulnar/radial blood flow volume ratio. When the blood flow is in the forward direction, in theory, brachial arterial blood flow and shunt blood flow do not have similar values. In this case, it was considered appropriate to evaluate the radial arterial blood flow volume (i.e., brachial arterial blood flow volume subtracted from brachial ulnar arterial blood flow).

Conclusion: In the present study, the clinical significance of the hemodynamics of the anastomotic distal portion of AVF using vascular-access ultrasonography was not clear. However, we clarified that the blood flow direction in the anastomotic distal portion was related to the ulnar/radial blood flow volume ratio. In addition, we proposed that shunt blood flow estimated from brachial arterial blood flow should be corrected when the blood flow direction of distal anastomosis detected forward blood flow.

Key words: arteriovenous fistula; anastomotic distal blood flow; steal syndrome; vascular-access ultrasonography

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This page was last modified on 2018-02-05T11:18:48.966+09:00


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