Background and purpose: Two randomized trials suggested that transcranial laser therapy (TLT) may benefit patients with acute ischemic stroke, although efficacy has not been confirmed. Supportive proof of concept could be demonstrated if TLT reduces the volume of cortical infarction.
Methods: The NeuroThera Efficacy and Safety Trial-2 (NEST-2) was a randomized trial of TLT versus sham in patients with acute ischemic stroke treated within 24 hours of onset. Infarct volumes were measured quantitatively and semiquantitatively on all protocol-required computed tomography (or MRI, if clinically indicated) scans performed on day 5 (±2). Two approaches assessed treatment effects on cortex: (1) indirectly, by analyzing total infarct volume among patients with clinical presentations suggesting cortical involvement; and (2) directly, by assessing the cortical Alberta Stroke Program Early CT Score (cASPECTS) components (M1-M6, anterior, posterior) on a 0- to 8-point modified scale.
Results: A total of 640 subjects had scans (576 computed tomography, 64 MRI) on day 5. The reliability of ASPECTS (intraclass correlation coefficient=0.85) and cASPECTS (intraclass correlation coefficient=0.82) was excellent, and total ASPECTS was correlated with total infarct volume (r=0.71). In the overall study population, there was no impact of TLT on total infarct volume (P=0.30), total ASPECTS (P=0.85), or cASPECTS (P=0.89). Similarly, no effect was seen in any of the following prespecified subgroups selected to indicate cortical involvement: baseline National Institutes of Health Stroke Scale score >10, Oxfordshire Total Anterior Circulation Syndrome, subjects with aphasia or extinction at baseline, or subjects with radiographic involvement of cortex.
Conclusions: TLT was not associated with a reduction in overall or cortical infarct volume as measured on computed tomography in the subacute phase.