Abstract
Clinical evidence for adding direct surgery to the management of patients with large vessel occlusion after mechanical thrombectomy failure is limited. We investigated which patients would benefit from the additional surgery. We retrospectively examined factors influencing mechanical thrombectomy success and the outcomes of patients receiving additional direct surgery. Direct surgery was performed in patients younger than 75 years with modified Rankin Scale 0-2 and with Diffusion-Weighted Imaging-Clinical mismatch in the middle cerebral artery area on post-mechanical thrombectomy magnetic resonance imaging. To convert the hyperdense artery sign into an objective index, the ratio of the occluded to the normal vessel in Hounsfield Units was calculated (defined as the hyperdense artery sign ratio). A total of 152 patients were included in this study; the median patient age was 77.0 years; 13 patients (8.5%) had posterior circulation occlusion, and effective recanalization was confirmed in 124 patients (82.8%). Multivariable analysis showed the factors significantly associated with successful recanalization to be male gender (p = 0.0020) and a higher hyperdense artery sign ratio (p = 0.0012). The cut-off value of the hyperdense artery sign ratio was 1.05. Additional direct surgery was performed in 6 of 28 patients with mechanical thrombectomy failure. In 5 of these patients, recanalization was not successful even with direct embolectomy, and bypass was added. Patients who underwent direct surgery had better modified Rankin Scale scores at discharge than those who did not (p = 0.0405). The hyperdense artery sign ratio was a predictor of mechanical thrombectomy success; if the hyperdense artery sign ratio was less than 1.05, mechanical thrombectomy was often unsuccessful, and an early conversion to direct surgery was deemed beneficial.