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Objective To analyze compensatory ability of the cerebral collateral circulation and relevant factors affecting cerebral ischemic tolerance for internal carotid artery (ICA) occlusion by Balloon Test Occlusion (BTO), providing reference basis for the selection of treatment methods in tumors or complicated aneurysms with ICA involved. Methods The clinical data of 87 cases BTO (85 patients, two of whom underwent bilateral BTO) of ICA in Tianjin Huanhu Hospital from June 2016 to September 2021 were analyzed retrospectively. The integrity of anterior or posterior of circulation structure, collateral compensatory capacity, tolerance to ICA occlusion and its influencing factors were analyzed. Results There were 8 [9.20% (8/87)] BTO positive cases. The positive rate was of cases with incomplete anterior communicating artery was higher than those with complete anterior communicating artery [3/5 vs. 6.10% (5/82); Fisher's exact probability: P=0.005]. The positive rate of cases with complete fetal posterior cerebral artery (fPCA) which was higher than those without complete fPCA [3/7 vs. 6.25% (5/80); Fisher's exact probability: P=0.015]. The positive rate of cases with non⁃open anterior circulation which was higher than those cases with open anterior circulation [3/6 vs. 6.17% (5/81); Fisher's exact probability: P=0.009]. The positive rate of cases with non⁃open posterior circulation which was higher than those cases with open posterior circulation [20% (5/25) vs. 0 (0/59); Fisher's exact probability: P=0.002]. Only the positive rate of patients with anterior circulation opening was higher than that of patients with open anterior circulation and open posterior circulation [13.04% (3/23) vs. 0 (0/3); Fisher's exact probability: P=0.022], neither anterior nor posterior circulation opening were significantly higher than those with only anterior circulation opening [2/2 vs. 13.04% (3/23); Fisher's exact probability: P=0.033] and both anterior and posterior circulation opening [2/2 vs. 0 (0/56); Fisher's exact probability: P=0.001]. Once the ICA occluded, the anterior circulation, the posterior circulation, both of anterior and posterior circulation could provide anterior cerebral artery (ACA) supplied area with compensatory blood flow for 88.10% (74/84), 3.57% (3/84), 5.95% (5/84) cases, respectively. The anterior circulation, the posterior circulation, both anterior and posterior circulation could provide middle cerebral artery (MCA) supplied area with compensatory blood flow for 27.38% (23/84), 16.67% (14/84), 53.57% (45/84) cases, respectively. There were statistically significant differences in the compensatory capacity between ACA (χ2=53.000, P=0.000) and MCA (χ2=54.244, P=0.000). The combined compensatory capacity of both anterior and posterior circulation was higher than that of single anterior circulation (Z=6.754, P=0.000; Z=6.180, P=0.000), single posterior circulation (Z=2.277, P=0.023; Z=5.065, P=0.000) and neither anterior nor posterior circulation (Z=1.991, P=0.047; Z=2.478, P=0.013). Conclusions The anterior circle is functionally much more important than the posterior circle. Non⁃open anterior circulation, especial absence of anterior communicating artery, complete fPCA, neither anterior nor posterior circulation were highly predictive for intolerance to ICA occlusion. For these cases, attention should be paid to the protection of ICA or active blood flow reconstruction technology to reduce the occurrence of cerebral ischemia. Those cases with both opened anterior circulation and opened posterior circulation provided higher compensatory ability than those with single circulation. For those cases, the ICA of could be sacrificed. |
