もやもや病に対するSTA-MCAバイパス術中に生じる脳表静脈の赤色化と術後脳血流増加との関連

抄録

Object: Superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis for moyamoya disease improves tissue oxygen metabolism by increasing perfusion pressure. On the basis of the hypothesis that an improvement in oxygen metabolism may increase venous oxygen saturation (SO₂), we assessed changes in venous redness, which reflect venous SO₂, during the revascularization surgery.
Methods: In this study, venous redness in subjects was quantitatively measured as an R value of RGB (red, green and blue) on the digital images of operative fields. First, to ensure whether redness of blood reflects SO₂, we studied the relationship between R values and the SO₂ levels of seven blood samples with various degrees of SO₂. Subsequently, by reviewing the video recordings of consecutive 14 STA-MCA anastomosis for moyamoya disease, changes in the R value (ΔR) of the cortical veins were compared with those in the regional cerebral blood flow (ΔrCBF) after the surgery.
Results: A positive correlation was noted between R values and SO₂ of the 7 blood samples (r² =0.847, P=0.003). The ΔR of the cortical veins during surgery positively correlated with ΔrCBF (r² =0.473, p=0.007). Notably, prominent venous reddening was associated with an excess increase in postoperative CBF (>150%).
Conclusions: During STA-MCA anastomosis, reddenings of cortical veins is proportional to increases in postoperative CBF. Prominent venous reddening, which may reflect excess oxygen supply, suggests postoperative hyperperfusion.