Perioperative cerebral microemboli in cardiac surgery are associated with postoperative neurologic complications. The EmBlocker (Neurosonix Ltd, Rehovot, Israel), a newly developed device should be positioned against the ascending aorta, and it produces an ultrasonic force expected to divert microemboli away from the cerebral vasculature and reduce cerebral emboli.Twenty-one consecutive patients, undergoing a valve procedure, were enrolled into this nonrandomized pilot study. The EmBlocker (Neurosonix Ltd) was positioned in 11 consecutive patients and activated for 1 minute (1.5 W/cm 2 ) during seven selected aortic manipulations and for 10 minutes (0.5 W/cm 2 ) intermittently after cross-clamp removal. Transcranial Doppler-based quantification of microembolic signals was performed in all patients.The use of the EmBlocker showed a significant overall reduction of the cerebral microembolic signals of 53%.The use of the EmBlocker during valve surgeries is associated with a reduction of perioperative cerebral microembolic signals. This new technology holds the potential to lower the risk of postoperative neurologic complications.