Successful endovascular therapy for acute ischemic stroke (AIS) requires optimal patient selection and effective tools, and also the rapid delivery of treatment from the time of symptom onset. Time to treatment for patients with AIS remains, arguably, the most important modifiable factor in improving outcomes.

Although intravenous tissue plasminogen activator (tPA) administration has been extended to 4.5 h,1 ,2 fewer than one-third of eligible patients receive it within the target door to needle (DTN) time of 60 min.3 This failure to achieve benchmark times has led to ‘Target: Stroke’, a national quality improvement initiative of the American Heart Association/American Stroke Association which aims to increase the timeliness of intravenous tPA administration. Over the past 20 years, tremendous efforts in developing primary stroke centers and implementing strategies based on the development of these centers have led to a dramatic reduction in DTN times, but there is much room for improvement.

Studies in myocardial infarction (MI) have shown the critical importance of time in improving outcome for patients undergoing percutaneous coronary intervention (PCI). In a large meta-analysis of 27 MI trials,4 a strong relationship between PCI-related time delay and benefits from primary angioplasty was observed in high-risk patients (r=–0.50, β= –0.075 (95% CI –0.189 to 0.04)), with 131 min as the equipoint between PCI and medical therapies. Moreover, for every 10 min reduction in time to PCI, MI mortality was also reduced.4 In a prospective PCI trial investigating the relationship between time and outcome, patients randomized <2 h after symptom onset demonstrated a strong trend towards a lower 30-day death rate with PCI than with medical treatment (2.2% vs 5.7%, p=0.058), with no difference observed in those randomized after 2 h.5

A similar emphasis on time to treatment in AIS studies has also …