MedWire News: The finding of recent silent ischemia (RSI) on magnetic resonance imaging (MRI) of stroke patients should not deter physicians from offering intravenous thrombolysis, research suggests.
Thrombolysis is currently contraindicated in patients with recent symptomatic ischemic stroke, but the guidelines do not cover patients with RSI.
"If confirmed, our findings will fill in the existing gap in rtPA [recombinant tissue plasminogen activator] guidelines concerning patients with RSI found on pretreatment MRI," say Catherine Oppenheim (Centre Hospitalier Sainte-Anne, Paris, France) and colleagues.
As reported in the journal Neurology, the team identified RSI in 18.3% of 115 stroke patients who underwent MRI prior to thrombolysis. RSI was identified as exhibiting well-developed FLAIR (fluid-attenuated inversion recovery) changes, whereas acute ischemic lesions did not. The RSIs were an average of 6.5 ml in volume.
Parenchymal hemorrhage type 1 or 2 on follow-up imaging according to the European Cooperative Acute Stroke Study (ECASS) criteria occurred in two (10%) patients with and 10 (11%) without RSI.
Of these 12 occurrences, eight occurred at the site of the acute infarct, one at the site of a RSI, one at the site of a microbleed, and two within normal brain tissue.
Symptomatic hemorrhagic transformation (ECASS criteria) occurred in 0% and 6% of the RSI-positive and negative groups, respectively. When defined by the broader National Institutes of Neurological Disorders and Stroke criteria, the corresponding rates were 5% and 11%.
In an accompanying editorial, Thierry Moulin and Fabrice Vuillier (University of Franche-Comte, Besancon, France) said: "The study highlights the need to consider the implications for existing protocols in light of results obtained with newer technologies."
They added: "In the same way as in the identification of microbleeds, the detection of RSI should lead to new comparative multimodal MRI studies, enabling the safety and continued effectiveness of tPA to be formally assessed, with new reliable criteria for subsequent guidelines."
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