In emergency department treatment of stroke patients, every second counts. Practice guidelines recommend giving ischemic stroke patients a clot-busting tPA injection within 60 minutes. So which takes longer: getting patients in the door and ready for imaging (door-to-imaging time, or DIT), or getting patients imaged and, if they’re suffering from ischemic stroke, giving them tPA (imaging-to-needle time, or ITN)?
Surprisingly, it’s the latter. At least, the finding surprised those who researched a new study on the respective times. In an article published online Monday in JAMA Neurology, the authors say that door-to-imaging time is “generally thought” to be the larger time consumer. Yet when they examined data from the Michigan Stroke Registry on 1,193 ischemic stroke patients treated during the period of 2009 through 2012, they found that the mean door-to-imaging time was 22.8 minutes. But the mean imaging-to-needle time was 60.1 minutes.
Most patients (68.4 percent) received brain imaging within the guideline-recommended 25 minutes. But only 28.7 percent of the patients went through the entire process and received tPA within the guideline-recommended 60 minutes. The researchers concluded, “Although timely brain imaging is clearly important for optimal tPA delivery and further improvement in DIT is desirable, we found that prolonged ITN time is a much greater problem.”
Why? Well, as the article points out, the imaging-to-needle time period involves a lot of moving parts:
The period between brain imaging and tPA delivery involves communication among emergency physicians, radiologists, neurologists, nursing, pharmacy, and the patient and family.
The researchers suggest that “increases in brain imaging capacity and availability, especially within emergency departments, have likely contributed to reductions in DIT.” They note that guideline recommendations and performance measures have focused on improving door-to-imaging times, not only driving improvements in the processes involved but also possibly shifting some delays “that are due to physician or patient decision making” into the imaging-to-needle time.
Beyond that, the researchers simply didn’t have enough data to draw conclusions. “We need to better understand the components of ITN time,” they wrote, “including laboratory testing, imaging interpretation, care coordination between physicians, ordering and preparing tPA, and medical decision making involving the physician, patient, and family.”
Related CME seminar (up to 71 AMA PRA Category 1 credits™): National Diagnostic Imaging Symposium™