A medical device deployment assembly includes a retractable sheath and a catheter positioned inside the retractable sheath. A medical device is compressed between an outer surface of the catheter and an inner surface of the retractable sheath. A spring is positioned inside the retractable sheath, and a pusher band is positioned inside the retractable sheath between the medical device and the spring. The spring biases the medical device deployment assembly toward a deployment configuration in which a distal tip of the retractable sheath is proximal to a proximal tip of the medical device.