Abstract: An automatic purse string suture device is disclosed that enables a surgeon to install a purse string suture in tissue structures, particularly for sealing the tissue about a cannula. The device is particularly suited for minimally invasive cardiothoracic procedures and is comprised of an applicator having an elongated structure with protrusions extending from the distal edge thereof. Also provided are means for advancing a needle through a passage to pass a suture through tissue that has been conformed to the distal edge of the device. Various means for conforming the tissue to the distal edge are disclosed as are methods for using the device to facilitate cardiothoracic surgery.