Background Strategies for patient selection for intra-arterial therapy (IAT) in acute ischemic stroke (AIS) are highly variable. The degree of protocol adoption and treatment rates associated with implementation of a service-wide patient selection IAT protocol were assessed.

Methods All patients with AIS prospectively recorded in our stroke database from January 2007 to June 2009 were reviewed. The IAT patient selection protocol was implemented in March 2008. Patients were defined as likely to benefit (LTB) from IAT if they had brain imaging completed within 6 h from last known well time, NIH Stroke Scale score ≥8, infarct volume ≤100 ml and evidence of proximal artery occlusion.

Results Of 1348 subjects identified, 118 (8.7%) met the criteria for LTB and 62 (52%) underwent IAT. There was a significant increase in rates of IAT among LTB patients after protocol implementation (61% vs 40%, p<0.02). In LTB patients, factors associated with IAT were stroke duration (OR 0.78, 95% CI 0.6 to 0.9 per hour), arrival within later calendar months during study period (OR 1.1, 95% CI 1.02 to 1.2 per month), intravenous tissue plasminogen activator (OR 0.6, 95% CI 0.4 to 0.9) and age (OR 0.98, 95% CI 0.95 to 1.02 per year). After multivariable adjustment, only stroke duration (OR 0.65, 95% CI 0.5 to 0.8 per hour) remained an independent predictor of IAT.

Conclusions Most patients with AIS did not meet our criteria for LTB and only 52% of those defined as LTB received IAT. Protocol adoption increased the use of IAT over time; however, further exploration of factors associated with the reasons for non-treatment and the impact of IAT on outcomes is necessary.