Background and objective: We aimed to evaluate the prognostic impact of the degree and time-point of arterial recanalization during the first 24h after tPA administration in patients with acute middle cerebral artery (MCA) occlusions.
Patients and method: We prospectively studied consecutive ischemic stroke patients treated with i.v. tPA following SITS-MOST criteria, who showed MCA occlusions on pre-bolus transcranial Duplex (TCCD) examinations. TCCD recordings were obtained 1, 2, 6, 12 and 24h after t-PA treatment. Thrombolysis in Brain Ischemia criteria were used to define complete, partial or absent MCA recanalization at each time point. Early neurological improvement (ENI) was defined as a decrease in 4 points in the NIHSS score during the first 24h. A modified Rankin scale score 2 at day 90 was considered indicative of good long-term clinical outcome.
Results: A total of 61 patients were included. Median baseline NIHSS score was 13 (interquartile range 9-18). ENI was observed in 32 (53%) patients. Complete, but not partial, recanalization at any time-point was independently associated with ENI in adjusted logistic regression models. The probability of ENI was maximal for <1h complete recanalization (OR 14.7, 95% CI [1.9-109.2], P=.009) and gradually decreased with later time-points. Thirty-five (57%) patients showed good long-term outcome. Both partial and complete MCA recanalizations achieved at any time-point during the first 12h after tPA bolus were independently associated with a good outcome. Odds ratio for favourable outcome was maximal (OR 33.7, 95% CI [2.2-520]; P=.012) when recanalization was achieved during tPA infusion.
Conclusions: Any degree of MCA recanalization observed during the first 12h following tPA administration predicted good long-term outcomes. Only complete recanalization was associated with early neurological improvement.