The significance of postbypass blood flow model in side to side bypass for moyamoya disease in predicting postoperative cerebral hyperperfusion syndrome.

OBJECTIVE

We previously developed the use of side to side (s-s) bypass for the treatment of adult moyamoya disease (MMD) and discovered several kinds of distinct blood flow models intraoperatively, which we observed through indocyanine green-video angiography (ICG-VA). The purpose of this paper was to investigate the correlation between blood flow model (BFM) identified in s-s bypass and the incidence of postoperative cerebral hyperperfusion syndrome (CHS) among patients with MMD.

METHODS

We analyzed 166 hemispheres from 153 patients diagnosed with MMD, including 118 hemispheres with s-s bypass and 48 with end to side (e-s) bypass. We categorized the enrolled patients into three pairs of comparison groups based on postoperative CHS (CHS or non-CHS) in s-s bypass, blood flow models (BFM I or BFM II) and surgical approach (s-s bypass or e-s bypass). Patients' demographics and characteristics were compared between groups.

RESULTS

Among patients who developed CHS, the occurrence of BFM I was more frequent than that of BFM II (0.154 vs. 0.019, = 0.029 < 0.05) and no significant differences were noted in the remaining data. In the group of blood flow models, the proportion of patients with a history of cerebral hemorrhage was higher in BFM II compared to BFM I (0.062 vs. 0.226, = 0.009 < 0.05), and the incidence of severity of ischemia was found to be higher in BFM I than in BFM II (0.774 vs. 0.429,  = 0.011 < 0.05), while the postoperative modified Rankin Scale (mRS) score and the Matsushima grade displayed no obvious difference. In comparison with the occurrence of CHS in e-s bypass group (7/48, 0.146), s-s bypass group had no difference (11/118, 0.093; = 0.323 > 0.05), BFM I group showed no discrepancy (10/65, 0.154, = 0.906 > 0.05) while BFM II group was different (1/53, 0.019, = 0.047 < 0.05).

CONCLUSION

The proportion of postoperative CHS occurring in BFM II during s-s bypass was lower than that in e-s bypass and BFM I. The postbypass blood flow model in s-s bypass may serve as a novel predictor for postoperative CHS.