Evaluation of STA-MCA bypass for Moyamoya disease with micro-Doppler monitoring

Abstract

Intraoperative hemodynamics in moyamoya disease (MMD) should be clarified to establish suitable treatments. We carried out micro-Doppler flowmetry during STA-MCA anastomosis for MMD.
Methods: Fifteen patients with MMD were treated by STA-MCA anastomosis, and a micro-Doppler probe was applied to the recipient arteries (M4) before and after anastomosis. Flow velocity (FV) and direction of blood flow were investigated proximal and distal to the anastomosis sites of the recipient arteries.
Results: Direction of blood flow in the pre-anastomosis artery (M4) was anterograde in 19 of 28 arteries (68%) and antidromic in g arteries (32%) .STA-MCA anastomosis produced a new direction of blood flow away from the anastomosis site in a proximal and distal direction in the recipient artery in 20 of 24 anastomoses. Only two anastomosis recipients showed antegrade flow, and two showed regurgitant flow. Time-averaged maximum flow velocity (V max) in M4 increased significantly from 11.4cm/s to 47.6 cm/s (p<0.001) following bypass surgery. Mean V max in the normal M4 recorded in patients with unruptured aneurysm was 14.0 cm/s.
Conclusion: This study demonstrated that FV in M4 is very low with regardant direction in many MMD patients, and that STA-MCA anastomosis can considerably increase FV of the MCA and change the direction of blood flow.