Abstract T P1: Higher Recanalization Rate with Stentrievers, but Outcome Not Improved

Abstract

Introduction: Intraveneous (iv) recombinant tissue plasminogen activator (tPA) is the evidence based treatment in acute stroke. Intraarterial treatment with tPA and/or instrumentation of the vessel with the attempt to manipulate the clot and remove it (called Intra Arterial Therapy (IAT)) is emerging as a tool for treating patients with contraindications to iv tPA or for patients with large clot burden, where iv tPA is often unsuccessful. IAT has been shown to have better recanalization rates than iv tPA (1), but in a randomized trial, IAT did not prove itself better than traditional iv tPA (2). Stentrievers (ST) are a new form of removable stent and it has shown promise in improving recanalization and outcome in IAT (3). Materials and methods: At our institution, 237 patients underwent IAT from 2004-2012. STs were used as part of the recanalization procedure in 92 patients. Results: Recanalization (defined as TICI 2b or 3) was achieved among 76 of the 92 patients=83 % in the ST group and in 61/145=42 % of the patients in the non-ST group, giving an odds ratio (OR) for recanalization using ST on 6.54 (p<0.0001). Good outcome defined as a modified Rankin Score (mRS) of 0-2 90 days after the stroke was achieved among 44/92=48% in the ST group and among 63/145=43% in the non-ST group. There was no statistical difference between these rates. Univariate analysis showed no differences in demographic data between ST and non-ST groups: Mean age 68 vs. 67 years (p=0.37), mean presenting NIHSS 17 vs. 16 (p=0.07) and time to groin puncture was 235 minutes in the ST group and 240 minutes in the non-ST group (p=0.17) (Mann-Whitney test). Conclusion: Recanalization is important for good outcome, but even though recanalization was achieved much more often in the ST group, this did not translate into better outcomes. Our findings are in line with the SWIFT study (3) where outcome defined as mRS 0-2 after 90 days were also not different between the ST group and the MERCI group. Manipulating the clot with the risk of distal embolization has been speculated to offset the benefit of recanalization (4).