Treatment and diagnosis of diseases of human vascular, digestive and other systems has been evolving from using open type surgical procedures to using newer minimally invasive techniques. The minimally invasive techniques generally involve placing a stent, stent-graft or ultrasound array into the lumen of a patient's diseased vessel. In the case of a vessel that has a reduced cross-sectional area due to disease, flow of bodily fluids through that vessel may be reduced or even prevented. Alternatively stents and stent-grafts may be used in the repair of aneurysmal vessels. An intraluminal device such as a stent or stent-graft placed into the diseased vessel can help return the vessel to pre-disease flow conditions by restoring the vessel to a more normal luminal configuration. Additionally, a stent-graft may prevent tissue in-growth from a diseased area migrating into an area of healthy tissue.
Intraluminal devices such as stents or stent-grafts can be generally grouped into two categories. One category includes devices that are assembled on top of an expanding means such as a balloon. When the device is delivered to the desired position within the anatomy, the balloon is expanded, causing the device to permanently expand to a larger diameter. The intraluminal device is then ductile enough so that it plastically deforms and remains in place in the anatomy when expanded. The other category of devices relates to “self-expanding” devices which are delivered to the desired site in the anatomy in a radially compressed state with some type of constraining means to prevent them from expanding until the clinician desires. Control of this “self-expansion” may be through many different methods. One method to control the “self-expansion” is through constraining the device with a sheath which can be actuated by the clinician when it is desired to release the constrained device for deployment. Such constraining sheaths, for example, may include one or more seams that can be remotely released via a pull line or other similar coupling member actuated by the clinician. When the seam is released, the self-expanding device is deployed, expanding to a larger diameter until contacting the luminal wall of the vessel.
Intraluminal devices such as stents or stent-grafts are generally delivered to the site of the disease via a catheter. Some disease sites are accessible with a short, relatively stiff catheter with an intraluminal device located near the distal end. These catheters are suitable, for example, where a percutaneous puncture is made for insertion of the catheter relatively close to the disease site. In these cases the catheter may be directly manipulated by the physician from the proximal end outside of the body. The physician may move the catheter longitudinally and rotationally in the proximity of the disease site until the device to be deployed is in its desired location.
In contrast, when the catheter insertion site is distant from the disease site, the catheter must be long and relatively flexible to allow navigation through tortuous anatomy and simultaneously suitably stiff for pushability to enable the catheter to be guided into place over a guidewire. This type of catheter may also have an intraluminal device loaded near its distal end. With this type of catheter, precise longitudinal (axial) and rotational control of the position of the device by the physician is made more difficult due to the length and flexibility of the catheter.
Possible references of interest may include U.S. Pat. No. 6,224,627 to Armstrong et al., U.S. Pat. No. 6,551,350 to Thornton et al. and US Published Patent Application 2007/0270781A1 to Burgermeister et al.