Residual Flow at the Site of Intracranial Occlusion on Transcranial Doppler Predicts Response to Intravenous Thrombolysis: A Multi-Center Study

Abstract

Background: We examined if transcranial Doppler (TCD) flow findings at the site of intracranial occlusions predict outcomes of stroke patients receiving intravenous rt-PA treatment. Subjects and Methods: TCD detected residual flow with the Thrombolysis in Brain Ischemia (TIBI) grading system before intravenous rt-PA bolus in patients with acute arterial intracranial occlusion. Timing and completion of early recanalization were measured for occlusive TIBI flow grades using TCD monitoring. Poor responders were defined as modified Rankin scores (mRS) >2 at 3 months. Results: A total of 361 patients with proximal arterial occlusion received intravenous rt-PA at 137.4 ± 36 min (median NIHSS 16). Mean age 69 ± 13, women: 168 (46.5%). Seventeen of 96 (17.7%) patients with TIBI 0, 41/124 (33.1%) with TIBI 1, 29/76 (38.2%) with TIBI 2 and 31/65 (47.7%) with TIBI 3 had achieved complete recanalization (p < 0.001). Higher NIHSS, SBP, glucose and lower TIBI grades were independent negative predictors of complete recanalization in the final logistic model. Patients with TIBI 0 had less probability of complete recanalization than patients with residual flow (TIBI 1–3) (OR_adj 0.4, CI 95% 0.22–0.8, p = 0.008). Median time to recanalization in patients with TIBI 0 was longer (155 min, interquartile range 104–190 min) than with TIBI ≥1 (120 min, range 60–170 min, p = 0.01, Mann-Whitney U test). In the stepwise multiple linear regression models adjusting for baseline characteristics, the only 2 factors that independently associated with time to recanalization were: time to rt-PA treatment and the absent flow (TIBI 0) on baseline TCD. Absent flow (TIBI 0) was associated with a longer time of recanalization of 35.2 min (95% CI 0.3–70.1 min, p = 0.048). Poor outcomes at 3 months were found in 61.3% of patients with no residual flow (TIBI 0), 56.9% with minimal (TIBI 1), 51.5% with blunted (TIBI 2), and 33.9% with dampened (TIBI 3) flows (p = 0.012). Patients with TIBI 0 have a higher likelihood of poor outcome (OR 3.1, 95% CI 1.5–6.4, p = 0.002). Patients who achieved complete recanalization have OR_adj 5.2 for good outcome (95% CI 2.8–9.8, p < 0.001). Conclusions: The pretreatment residual flow at intracranial occlusion predicts the likelihood of complete recanalization, time of recanalization and long-term outcome. No detectable residual flow indicates the least chance to achieve recanalization and recovery with systemic thrombolysis and may support an early decision for combined endovascular rescue.