Direct aspiration for thrombectomy in ischemic stroke: Impact of dwell time

Objective To evaluate the impact of dwell time on the efficacy of the direct aspiration thrombectomy in ischemic stroke. Methods The study is a review of our prospective cerebral thrombectomy database of subjects admitted from January to December 2017. We performed direct aspiration with 2 min dwell time as recommended by the manufacturer (group 1) and 5 min dwell time (group 2) between January–June and July–December, respectively. The primary outcome was successful reperfusion after the first pass defined as modified Thrombolysis in Cerebral Infarction scores 2 b/3. Results Eighty-five patients had a cerebral thrombectomy by direct aspiration, 45 in group 1 and 40 in group 2. There was no statistically significant difference between the two groups but a trend toward a better modified Thrombolysis in Cerebral Infarction first pass 2 b/3 rate in group 2 (70% versus 48.8%, p = 0.06). Although not statistically significant (p = 0.07), the ratio of rescue therapy with stent retriever was higher in group 1 (40%) than in group 2 (22.5%). After all passes, modified Thrombolysis in Cerebral Infarction 2 b-3 was obtained in 82.2% (37/45) of cases in group 1 and in 90% (36/40) of cases in group 2. Among 76 patients (89.5%) with modified Rankin Scale assessment at three months, no significant difference (p = 0.3) was found in the proportion of functionally independent individuals between groups 1 and 2 (51.8% versus 55.6%, respectively). Conclusion Although statistical significance was not reached, our retrospective analysis exhibited a strong trend toward modified Thrombolysis in Cerebral Infarction first pass improvement when dwell time was increased from 2 to 5 min.