Implantable pacemakers and automatic implantable defibrillators contain intravascular leads that are typically inserted into a blood vessel of a patient, for instance, the internal jugular or subclavian vein. Such a lead can be advanced into the heart, where the distal section of the lead can be attached to the endocardial surface. Over time, however, the lead may fracture and become non-functional, so that a new lead may need to be inserted to replace the existing lead. The inoperative lead may also need to be removed from the vascular system, overtime, as it may get infected and may increase likelihood of blood clot formation. Removal of an inoperative lead, however, is oftentimes difficult because such a lead may have become ingrown within the vascular system, where fibrous adhesions may have formed between the lead and blood vessels.
Inoperative lead, in general, may sometimes be removed by simply pulling the free end of the lead to separate the lead from fibrous adhesions. However, this may lead to the creation of emboli in the blood stream by dislodging the fibrous adhesions in whole or in part, and may result in severe complication or even death of the patient. Several systems have been proposed for removal of inoperative leads. For example, U.S. Pat. No. 4,582,056 to McCorkle, Jr. et al. discloses a system that places a locking stylet inside the lead, enabling the physician to place traction on the lead. Sheaths of increasing diameter may then be advanced over the lead and rotated to disrupt the adhesions and allow lead removal. Because most leads have a substantially soft body, when an extraction sheath is advanced, the lead will tend to buckle and bunch up in front of the distal cutting end of the sheath. The buckling lead can increase the potential for the extraction sheath to veer out of axial alignment with the vein, and cut through the wall of the vein during advancement. This potential of the lead to bunch up and veer out of axial alignment can be increased in more recent extraction systems, because the more recent systems also include laser or radiofrequency cutting energy in addition to an extraction sheath.
Accordingly, there is a need for improved systems and methods for extraction of implanted articles, that can easily extract intravascular leads without some o the issues noted.
USPTO Backgrounds
USPTO Backgrounds