The evidence continues to mount that, simply, we’re doing it wrong.
Part of this is an acceptable confusion: we didn’t have the computational power or acquisition resolution capable of evaluating the intracranial circulation or perfusion when treating stroke. However, as the evidence continues to mount from advanced imaging, it seems clear the “time” aspect is not the best determinant of outcome in stroke.
This is a small review of patients from DUST and MR CLEAN with MCA stroke and CT perfusion imaging available. CTA is frequently performed to evaluate intracranial vasculature and estimate collateral circulation, but CT perfusion provides a dynamic look at contrast flow throughout the brain.
Based on this small 70 patient cohort, the reliability of the observations is hardly bulletproof, with wide 95% confidence intervals. However, there is a reasonable, linear decrease in good outcomes as poor perfusion characteristics proliferate. The best perfused collateral circulation led to 15 of 26 patients recovering to mRS 0-2. While the flow rate and quality of the collaterals degraded, those with good recovery dropped to 12 of 26, then 1 of 12, and finally to 0 of 6.
The horizon is not far now where, hopefully, we’ll look back at the “time is brain” mantra as the infantile scramblings of the dark ages of acute stroke treatment. Better imaging technology continues to demonstrate some brain is unrecoverable, regardless of timeframe, while others are likely excellent candidates for preservation of some function. We ought to have much better options for tailoring treatment to the individual in the near future – and as this technology spreads.
“Impact of Collateral Status Evaluated by Dynamic Computed Tomographic Angiography on Clinical Outcome in Patients With Ischemic Stroke”
http://www.ncbi.nlm.nih.gov/pubmed/26542691