Cerebral damage, time dictate benefits of recanalization
MedWire News: The extent of changes on computed tomography (CT) scans and the speed at which recanalization is achieved determine whether stroke patients will benefit from endovascular treatment, say Canadian researchers.
Stroke patients with extensive changes on CT are unlikely to benefit, they report, whereas those with some evident damage may still benefit if recanalization is achieved quickly.
"An endovascular approach to acute stroke treatment is expensive, resource-intensive, and sometimes has significant procedural risks," say Mayank Goyal (Foothills Medical Center, Calgary, Alberta) and colleagues.
"We therefore suggest that proper patient selection using baseline CT scan, allied to efficient strategies aimed at faster recanalization, will result in better clinical outcomes in patients with acute ischemic strokes treated using endovascular techniques."
The researchers used data from 85 patients in the Penumbra Pivotal Trial, which had a 27.7% good outcome rate (modified Rankin Scale =2), despite 81.2% of patients achieving recanalization.
They report that 50% of patients with a favorable pre-treatment CT scan - defined as an Alberta Stroke Program Early CT Scale (ASPECTS) score of 8-10 - achieved a good outcome, compared with 15% of those with lower scores.
No patient with an ASPECTS score of 4 or lower achieved a good outcome, regardless of whether they recanalized, they note in the journal Stroke. And no patient without recanalization had a good outcome.
Time to recanalization also affected the likelihood of good outcomes. In patients with ASPECTS scores of 8-10, this was achieved by 62.5% of those who recanalized up to 300 minutes after symptom onset, compared with 45.5% of those who recanalized later.
The effect was even more marked in patients with lower ASPECTS scores, at corresponding rates of 33.3% versus 7.9%.
"The best outcomes are achieved among patients with favorable scans and fast recanalization times," say Goyal et al, describing this as "biologically intuitive."
They add that "the evidence of the interaction between baseline CT scan and onset-to-recanalization time is particularly appealing given our understanding of modern imaging."
But the team stresses: "At any treatment time point, if there are extensive changes on CT scan (ASPECTS =4), then endovascular therapy simply does not help."
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By Eleanor McDermid