Abstract Body: Background: Thrombectomy for acute major vessel occlusion is a well-established procedure for preventing stroke. However, cases of futile recanalization, where tissue no-reflow persists despite successful reperfusion, have been observed. The aim of this study is to assess cerebral hemodynamics immediately after successful thrombectomy regarding clinical outcome.
Methods: We prospectively registered cases that achieved successful thrombectomy (mTICI≧2b) for ICA and MCA. Pre-operative evaluation included MR imaging. Thirty minutes after recanalization, flat panel CT perfusion imaging was performed, and CBF, CBV, Tmax, mismatch ratio and hypoperfusion index were calculated with Rapid ANGIO. We examined the correlation of these parameters with infarct expansion, hemorrhagic transformation and clinical outcome.
Results: Analysis was conducted on 65 consecutive cases with successful recanalization. Infarct expansion defined as ASPECTS decrease occurred in 23 cases (35.4%), with a significantly lower percentage of susceptibility vessel sign, higher CBF<45% area, and lower favorable clinical outcome. CBF<45% area, not Tmax>6s, significantly correlated with final ASPECTS (r=-0.57, p<0.001). Interestingly, mismatch ratio was higher in the group without infarct expansion. Hemorrhagic transformation occurred in 26 cases. The groups with hemorrhagic transformation showed a higher CBF<45% and CBV<34% area, and hypoperfusion index was higher in parenchymal hematoma. These post-operative parameters significantly contributed to clinical outcome three months after onset.
Conclusions: No-reflow phenomenon could be detected after successful thrombectomy with flat panel CT perfusion, suggesting that major vessel recanalization does not necessarily equate to immediate tissue reperfusion. Our study highlights post-thrombectomy hemodynamic mismatch and collaterals as potential indicators for the effectiveness of thrombectomy.