Abstract: An RF ablation system includes a catheter and an RF electrode that delivers RF electrical energy to the site of an occlusion. The system includes a mechanism for minimizing the likelihood that RF electrical energy will be applied directly to the vessel wall. In one embodiment of the invention, the catheter includes a number of tissue expanding jaws to engage a vessel wall and push the vessel wall away from the electrode to shield vessel walls from the electrode. In yet another embodiment of the invention, the electrode has a spiraled distal end with a radius that is larger than the radius of the catheter, such that the electrode engages the vessel wall and pushes the wall away from a conducting portion of the electrode. The portion of the electrode that engages the vessel wall is preferably coated with an insulating material to prevent delivery of RF electrical energy directly to the vessel wall.

Abstract: A combination catheter includes an ultrasound transducer and RF ablation electrode. The ultrasound transducer transmits ultrasound signals into and receives echo signals from a vessel. The echo signals are processed and used to produce an image of the tissue surrounding the catheter. A driveshaft rotates the ultrasound transducer to obtain a 360° view of the vessel wall. At the distal end of the driveshaft is an electrode. An RF generator is electrically coupled to the driveshaft to deliver RF energy to the electrode at the distal end of the driveshaft to ablate occluding material in the vessel. The electrode may have a variety of tip shapes including concave, roughened, or expandable configurations, depending on the size of the vessel and composition of the occluding material to be ablated. Alternatively, the RF ablation energy may be delivered to a guidewire that is used to route the ultrasound catheter through a patient's vasculature.

Abstract: A system for recanalizing an occluded blood vessel including a centering catheter employed to center an ablative guide wire within the blood vessel as the guide wire traverses the occlusion. The centering catheter includes a catheter body with an operative lumen through which the ablative guide wire is slidingly disposed. The centering catheter further includes a distally disposed centering mechanism that, when activated, centers the ablative guide wire within the blood vessel as it traverses the occlusion. The centering mechanism can comprise various embodiments including a single inflatable balloon or segmented inflatable balloon, which is in fluid communication with an inflation lumen. An airless preparation lumen may be disposed within the inflation lumen for ease of centering catheter preparation. The ablative guide wire includes insulation that is preferably formed of heat shrink tubing, which is stretched prior or concurrently with the heating process.

Abstract: A system for recanalizing an occluded blood vessel including a centering catheter employed to center an ablative guide wire within the blood vessel as the guide wire traverses the occlusion. The centering catheter includes a catheter body with an operative lumen through which the ablative guide wire is slidingly disposed. The centering catheter further includes a distally disposed centering mechanism that, when activated, centers the ablative guide wire within the blood vessel as it traverses the occlusion. The centering mechanism can comprise various embodiments including a single inflatable balloon or segmented inflatable balloon, which is in fluid communication with an inflation lumen. An airless preparation lumen may be disposed within the inflation lumen for ease of centering catheter preparation. The ablative guide wire includes insulation that is preferably formed of heat shrink tubing, which is stretched prior or concurrently with the heating process.

Abstract: An intravascular device and methods for forming multiple percutaneous myocardial revascularization (PMR) holes in a heart chamber wall simultaneously. One device includes a basket formed of flexible arms carrying cutting probes over their length. The basket arms are outwardly arcuately biased so as to assume an outwardly bowed, arcuate shape when unconstrained. The device includes an inner shaft distally secured to a proximal portion of the basket and slidably disposed within an outer shaft. The inner shaft and collapsed basket can be retracted within the outer shaft, delivered intravascularly to the left ventricle, and distally advanced, forcing the basket to assume the bowed shape. Radio frequency current supplied to the electrical cutting probes burn holes into the ventricle wall and myocardium. One embodiment has high pressure fluid jet cutting means. Another embodiment uses a basket as an anchor to position a steerable cutting probe.