Abstract: Instrumentation for percutaneous delivery of blood filtration devices to atrial appendages includes a curved access sheath and a delivery tube. The curved access sheath is coursed through the patient's vasculature to gain transseptal access to a left atrial appendage. A compressed filter device attached to a tether wire is loaded in the delivery tube. The loaded delivery tube is advanced through the pre-positioned access sheath to place the device in a deployment position. The access sheath and the delivery tube can be mechanically locked and moved together to place the device in a suitable deployment position. The device is deployed by expelling it from the delivery tube either by retracting the delivery tube over the tether wire, or by moving the tether wire forward through the delivery tube. The expelled device, which is not constrained by the delivery tube walls, self expands to its useful size in the subject atrial appendage.