It is well-established many patients with minor or rapidly improving stroke fail to thrive. The NIHSS is a crude tool, and its correlation with infarct size and ultimate disability is limited. It is not inconceivable some patients with minor stroke could be candidates for intervention. However, these patients would need to fit our critical requirements: 1) there must be substantial at-risk territory preserved by collateral perfusion, and 2) the occluded vessel must be reliably opened at a greater rate and timelier fashion than the body’s natural recanalization process.
This brief report is an interesting stepping stone on the pathway towards the practical realization of some of these issues. These authors present a retrospective review of patients with minor stroke (NIHSS ≤ 3) evaluated at their institution. Their institution routinely performs CT imaging with perfusion (RAPID software) on most stroke evaluations. They further trim out 73 of these patients for whom the CT perfusion demonstrated substantial volumetric deficits. Generally, these were patients with small (<5 mL) core infarcts surrounded by 20-40 mL of delayed perfusion, as would be reasonably expected for patients with minimal clinical symptoms.
There were 34 patients in this cohort who received tPA and 39 who were admitted without. Patients were generally similar, although the tPA cohort had twice the prevalence of prior stroke (29.4% vs. 16.7%) and – most importantly – double the area of delayed perfusion (41.3 mL vs. 25.1 mL with wide standard deviation). Despite these poorer prognostic features, 90-day mRS 0-1 were 91.2% in the tPA cohort and 71.8% in the standard care.
This is hardly practice changing in its crude, non-randomized, retrospective form. It does, however, have face validity for informing future study. It also fits with the paradigm of stroke care I’ve been promoting on this blog for years – the inanity of unselected tPA – and the requirements as above – to maximize potential benefit by ensuring those offered tPA have salvageable tissue (read: small core, large mismatch) and likely to recanalize (read: small vessel). There’s virtually no question CTP or its equivalent needs to become part of the treatment decision-making process, rather than simple non-contrast CT or even CTA without evaluation of collateral flow.
“Utility of Computed Tomographic Perfusion in Thrombolysis for Minor Stroke”
http://stroke.ahajournals.org/content/early/2016/05/19/STROKEAHA.116.013021.abstract
https://m.youtube.com/watch?v=co0Eum33tOI