The Evolution of Transcranial Laser Therapy for Acute Ischemic Stroke, Including a Pooled Analysis of NEST-1 and NEST-2

Intravenous tissue plasminogen activator is the only proven therapy for acute ischemic stroke. Not enough patients are eligible for treatment and additional new therapies are needed. Recently, laser technology has been applied to acute ischemic stroke. This noninvasive technique uses near-infrared wavelengths applied to the scalp within 24 h of symptom onset. The mechanism is incompletely understood but may involve increased mitochondrial adenosine triphosphate production. Animal models demonstrated safety and efficacy warranting randomized controlled trials in humans. NEST-1 (phase 2) and NEST-2 (phase 3) confirmed the safety of transcranial laser therapy, although efficacy was not found in NEST-2. Pooled analysis of NEST-1 and NEST-2 revealed a significantly improved success rate in patients treated with laser therapy. Further phase 3 testing is planned and may create a new paradigm for the treatment of acute ischemic stroke.