Timing of vessel imaging for suspected large vessel occlusions does not affect groin puncture time in transfer patients with stroke

Background: Access to endovascular therapy (ET) in cases of acute ischemic stroke may be limited, and rapid transfer of eligible patients to hospitals with endovascular capability is needed.

Objective: To determine the optimal timing of diagnostic CT angiography to confirm large vessel occlusion (LVO).

Methods: Of 57 emergency department transfers to Mount Sinai Hospital (MSH) for possible ET from January 2015 through March 2016, 39 (68%) underwent ET, among whom 22 (56%) had CT angiography before transfer and 17 (44%) had CT angiography on arrival. We compared mean outside hospital arrival to groin puncture (OTG) time between the two groups using t-tests and Wilcoxon rank sum tests. OTG was defined as the difference between groin puncture and outside hospital arrival time minus ambulance travel time.

Results: Average age was 73±13 years and average National Institute of Health Stroke Scale score was 19±5. There was no difference in average OTG time between the two groups (191 min for CT angiography at outside hospital vs 190 min for CT angiography at MSH (p=0.99 for t-test and 0.69 for rank sum test)). Among the 18 patients who were transferred but did not receive ET, 10 had no LVO, 5 had large established infarcts on arrival and 3 had post-tissue plasminogen activator hemorrhage. In 9/10 patients without LVO, CT angiography was not performed before transfer.

Conclusions: CT angiography timing in the transfer process does not affect OTG time, but 90% of patients without LVO had not had CT angiography before transfer. Hence, it might be beneficial to obtain a CT angiogram at the outside hospital, if it can be acquired and read rapidly, to avoid the cost and potential clinical deterioration associated with unnecessary transfers.