Thrombolytic therapy for acute ischemic stroke after recent transient ischemic attack

Background and aim: Safety and efficacy of intravenous thrombolysis in stroke patients with recent transient ischemic attack are hotly debated. Patients suffering transient ischemic attack may present with diffusion-weighted imaging lesions, and although normal computed tomography would not preclude thrombolysis, the concern is that they may be at higher risk for hemorrhage post-thrombolysis treatment. Prior ipsilateral transient ischemic attack might provide protection due to ischemic preconditioning. We assessed post-thrombolysis outcomes in stroke patients who had prior transient ischemic attack.

Methods: Multicentered prospective study of consecutive acute stroke patients treated with intravenous tissue plasminogen activator (tPA). Ipsilateral transient ischemic attack, baseline characteristics, risk factors, etiology, and time-lapse to treatment were recorded. National Institutes of Health Stroke Scale at seven-days and modified Rankin Scale at three-months, symptomatic intracranial hemorrhage, and mortality were compared in patients with and without transient ischemic attack.

Results: There were 877 patients included, 60 (6·84%) had previous ipsilateral transient ischemic attack within one-month prior to the current stroke (65% in the previous 24 h). Transient ischemic attack patients were more frequently men (70% vs. 53%; P = 0·011), younger (63 vs. 71 years of age; P = 0·011), smokers (37% vs. 25%; P = 0·043), and with large vessel disease (40% vs. 25%; P = 0·011). Severity of stroke at onset was similar to those with and without prior transient ischemic attack (median National Institutes of Health Stroke Scale score 12 vs. 14 P = 0·134). Those with previous transient ischemic attack were treated earlier (117 ± 52 vs. 144 ± 38 mins; P < 0·005). After adjustment for confounding variables, regression analysis showed that previous transient ischemic attack was not associated with differences in stroke outcome such as independence (modified Rankin Scale 0-2) (odds ratios: 1·035 (0·57-1·93) P = 0·91), mortality (odds ratios: 0·99 (0·37-2·67) P = 0·99), or symptomatic intracranial hemorrhage (odds ratios: 2·04 (0·45-9·32) P = 0·36).

Conclusions: Transient ischemic attack preceding ischemic stroke does not appear to have a major influence on outcomes following thrombolysis. Patients with prior ipsilateral transient ischemic attack appear not to be at higher risk of bleeding complications.