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This case shows how intraoperative Transit Time Flow Measurement (TTFM) and High-Frequency Ultrasound (HFUS) revealed a dissection in the outflow vein resulting in immediate revision.
Vein dissection in a forearm AV fistula
Case story
Patient information
- 51-year-old male
- 2019 myocardial infarction (LAD Stenting)
- 2022 PCI (2 stents)
- Hypertonus and Hyperlipidemia (Lipoprotein α: 107mg/dl)
→ Indication: Lipoprotein Apheresis
Intraoperative completion control
The surgical plan was to create a radio-cephalic side-to-end fistula. Preoperative vessel mapping showed a suitable artery and a good cephalic vein at the forearm. The initial transit time flow measurement (Image 1) after the creation of the fistula showed acceptable flow but no thrill. The flow quickly decreased to values below 100 mL/min.
High-frequency ultrasound was used to identify the cause for the low flow revealing a dissection in the outflow vein proximal to the anastomosis. The videos below show the transverse view of the dissection including a floating vein valve and the longitudinal view visualizing the bloodstream pumping against an occlusion.
Video 1: Transverse view
Video 2: Longitudinal view
Revision
The resected vein was cut open to inspect the dissection (Image 2). The Cimino fistula was abandoned, and a new forearm fistula was created more proximally (Image 3).
The final TTFM showed adequate flow. There were also a good thrill and murmur (Image 4 and Image 5).
Summary
TTFM assisted in identifying flow issues and HFUS helped in identifying the problem. Final TTFM assured the surgeon that the flow was adequate for maturation of the fistula.
Case attachments
Click images below to view.
Initial TTFM showing acceptable flow but no thrill
Resected vein cut open to inspect the dissection
New forearm fistula created more proximally
Probe placement on outflow vein
Final TTFM showing acceptable flow
Technology used
Medistim MiraQTM Vascular System with Medistim TTFM probes and Medistim L15 Ultrasound Probe.
