Futile inter-hospital transfer for mechanical thrombectomy in a semi-rural context: analysis of a 6-year prospective registry

Background and purpose Inter-hospital transfer for mechanical thrombectomy (MT) might result in the transfer of patients who finally will not undergo MT (ie, futile transfers [FT]). This study evaluated FT frequency in a primary stroke center (PSC) in a semi-rural area and at 156 km from the comprehensive stroke center (CSC). Methodology Retrospective analysis of data collected in a 6-year prospective registry concerning patients admitted to our PSC within 4.5 hours of acute ischemic stroke (AIS) symptom onset, with MR angiography indicating the presence of large vessel occlusion (LVO) without large cerebral infarction (DWI-ASPECT ≥5), and selected for transfer to the CSC to undergo MT. Futile transfer rate and reasons were determined, and the relevant time measures recorded. Results Among the 529 patients screened for MT, 278 (52.6%) were transferred to the CSC. Futile transfer rate was 45% (n=125/278) and the three main reasons for FT were: clinical improvement and reperfusion on MRI on arrival at the CSC (58.4% of FT); clinical worsening and/or infarct growth (16.8%); and longer than expected inter-hospital transfer time (11.2%). Predictive factors of FT due to clinical improvement/reperfusion on MRI could not be identified. Baseline higher NIHSS (21 vs 17; P=0.01) and lower DWI-ASPECT score (5 vs 7; P=0.001) were associated with FT due to clinical worsening/infarct growth on MRI. Conclusions In our setting, 45% of transfers for MT were futile. None of the baseline factors could predict FT, but the initial symptom severity was associated with FT caused byclinical worsening/infarct growth.