Henry Ford Hospital Medical Journal


The effect of STA-MCA bypass on regional cerebral bloodflow (rCBF) is unclear Since asymmetries of rCBF have previously been shown to identify the focus of maximal cerebral ischemia, a study was performed to assess the effects of surgical revascularization on rCBF in this focus. Sixteen candidates for STA-MCA bypass were studied preoperatively and postoperatively. The rCBF vms measured by the '"Xenon inhalation technique with eight contralateral probe pairs. The probe pair with the maximal percentage difference in initial slope index (ISI) was identified and corresponded to the clinically involved hemisphere in 14 patients. Following surgery, the ISI increased in the region of maximal ischemia (from 36.0 ± 8.0 to 42.0 ± 9.0, p < 0.05), and the asymmetry of flow was reduced (from 16.8 ± 8.0 to 8.6 ± 9.8, p < 0.001). Hemispheric ISI and hemispheric asymmetry of ISI remained unchanged after surgery. The results suggest that STA-MCA bypass may effectively increase flow in a focus of ischemial oligemia. The clinical significance of this improvement in rCBF must await further study.