Based on preclinical evidence, phosphodiesterase-5 inhibitors (PDE5-Is) may benefit neurovascular function, this systematic review and meta-analysis evaluated their effects on cerebral hemodynamics, cognitive function, and safety in patients with cerebral small vessel disease (CSVD).<h4>Methods</h4>We systematically searched four major databases from January 1990 to October 2025 for randomized controlled trials investigating sildenafil or tadalafil in adults with CSVD. Here, PDE5A is linked to cerebral small vessel disease.