Article
Intraoperative quantitative assessment of vessel flow facilitates decision making during high-flow bypass surgery
Die intraoperative quantitative Erfassung des Gefäßflusses erleichtert den Entscheidungsprozess im Rahmen der High-Flow-Bypass-Chirurgie
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Authors
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Peter Vajkoczy
- Neurochirurgische Klinik, Universitätsklinikum Mannheim, Universität Heidelberg, Mannheim
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T. Kinfe
- Neurochirurgische Klinik, Universitätsklinikum Mannheim, Universität Heidelberg, Mannheim
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P. Horn
- Neurochirurgische Klinik, Universitätsklinikum Mannheim, Universität Heidelberg, Mannheim
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P. Schmiedek
- Neurochirurgische Klinik, Universitätsklinikum Mannheim, Universität Heidelberg, Mannheim
| Published: | April 23, 2004 |
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Outline
Text
Objective
Decision making during high-flow bypass procedures is hampered by the lack of adequate intraoperative information on blood flow through the graft. Thus, patients may be placed at risk of ischemia or parent vessel sacrifice may be delayed risking bypass thrombosis. The aim of the present study was to evaluate the benefits of quantitative vessel flow measurments on decision making during high-flow bypass surgery.
Methods
Over one year, 18 patients underwent high-flow bypass procedures. In 9 patients (n=7 giant or large aneurysms within the anterior or posterior circulation, n=1 skull base tumor, n=1 ischemia), intraoperative bypass vessel flow measurements were performed using ultrasound transit-time technology. Therefore, perivascular probes (3 and 6 mm) were placed around the bypass and graft flow (ml/min) was continuously recorded. In the aneurysm and tumor cases, measurements were performed before (baseline flow) and after test parent vessel occlusion (test occlusion flow) in order to assess whether graft flow was sufficient to replace flow through the parent vessel that was to be sacrificed.
Results
Flow measurements were characterized by stable and reliable readings. The information about vessel flow markedly improved the intraoperative assessment not only of bypass patency but also of bypass function, which consequently facilitated decision making on the timing of parent vessel sacrifice. In the ischemia case, bypass flow was 220 ml/min. In the aneurysm and tumor cases, baseline flow and test occlusion flow were 65±59 and 116±45 ml/min, respectively. Preliminary thresholds for aneurysm cases were identified: a baseline flow less than 40 ml/min carries a high risk of bypass thrombosis; test occlusion flows greater than 50 and 100 ml/min allow for a safe intraoperative occlusion of the M1 segment and ICA, respectively.
Conclusions
The quantitative assessment of vessel flow provides unique intraoperative information on not only the patency but also the function of bypass grafts and facilitates decision making during high-flow bypass surgery.
