Abstract Body: Introduction: Large vessel recanalization (LVR) is a well described phenomenon following intravenous thrombolysis (IVT). However, predictors of LVR are elusive, and whether early LVR for large vessel occlusion (LVO) is beneficial for patients who cannot undergo immediate endovascular thrombectomy (EVT) is unclear. Moreover, the interplay between collateral circulation and the likelihood of LVR is poorly understood and even less studied.
Methods: This was a retrospective study at a comprehensive stroke center that centralizes patient transfers for EVT from a network of 15 hospitals. Adult patients with an internal carotid artery or middle cerebral artery LVO who received IVT and did not undergo EVT within one hour of LVO diagnosis were included. Clinical and radiographic information at the time of LVO diagnosis were collected. Collateral status was graded using the Tan score (Tan CS). LVR was defined as vessel recanalization identified on repeat vessel imaging leading to a decision to defer EVT. The primary endpoint was infarct progression defined as decrease in ASPECTS of two or more. The secondary endpoint was 90-day modified Rankin Scale (mRS) outcomes. Multivariable logistic regression models were used to adjust for various confounders.
Results: Of the 150 patients included, 42 (28.0%) experienced LVR prior to EVT. LVR patients had lower NIH Stroke Scale (p=0.006) and higher Tan CS (p=0.019). In multivariable analyses, LVR was associated with significantly lower odds of infarct growth (OR 0.15 [95%CI 0.07-0.36], p<0.001), and compared with patients who underwent successful EVT recanalization, lower 90-day mRS (common OR 0.44 [95%CI 0.22-0.90], p=0.024). Higher Tan CS was significantly associated with higher odds of LVR (2.95 [95%CI 1.60-5.45], p<0.001), and both collateral status and LVR were independently associated with lower odds of infarct growth (0.34 [95%CI 0.18-0.63], p<0.001 and OR 0.21 [95%CI 0.09-0.52], p<0.001, respectively).
Conclusions: LVR with IVT prior to EVT was significantly associated with lower odds of infarct progression and better clinical outcomes. Better collateral circulation was independently associated with both higher odds of LVR, as well as lower odds of infarct progression. In conclusion, these findings suggest the clinical benefit of LVR for patients who cannot receive timely EVT and highlight the potential for modulating collaterals with the goal of limiting infarct growth and maximizing the odds of LVR.