Time to recanalization and risk of symptomatic intracerebral haemorrhage in patients treated with intravenous thrombolysis

Background and purpose: To test whether time to recanalization is associated with a progressive risk of symptomatic intracerebral haemorrhage (SICH) after intravenous alteplase (IVT), we conducted a serial transcranial duplex monitoring study up to 24 h after IVT in a cohort of 140 patients with acute ischaemic stroke attributed to large artery occlusion in the anterior circulation.

Methods: Patients were classified in four groups according to the time to complete recanalization (Thrombolysis in Brain Ischaemia, TIBI grades 4 or 5) after alteplase bolus: <2 h (n = 53), 2-6 h (n = 9), 6-24 h (n = 32) and no recanalization (NR) at 24 h (n = 46). SICH was defined as any haemorrhagic transformation with National Institute of Health Stroke Scale (NIHSS) score worsening ≥ 4 points (European Australian Acute Stroke Study II, ECASS II criteria) or parenchymal haematoma type 2 with neurological worsening (SITS-MOST criteria) in the 24-36 h CT. Favourable outcome was defined as modified Rankin score ≤ 2 at 3 months.

Results: There were no differences between the groups of patients who recanalized at each time frame regarding localization of the occlusion (P = 0.29), stroke severity at baseline (P = 0.22) and age (P = 0.06). SICH (ECASS/SITS-MOST) was observed in 5.7%/5.7% of the patients who recanalized in <2 h, in 0%/0% of the patients who recanalized between 2-6 h, in 3.1%/3.1% of the patients who recanalized within 6-24 h and in 2.2%/0% of those patients who did not recanalize at 24 h. The rate of favourable outcome according to the time of recanalization was 79.2%, 50%, 46.9% and 34.1% (P < 0.001).

Conclusions: Our findings are in line with the literature showing a relationship between time to recanalization and functional outcome after IVT in acute stroke, but they do not confirm a progressive increase in the rate of SICH.