An apparatus and method for occluding a lumen, such as a vessel, in a mammal using alternating current and monitoring reflected power from the occlusion site to determine vessel constriction and/or electrocoagulation. The apparatus is provided with an alternating current (AC) power generator, a first electrode electrically coupled to the generator, a dispersive electrode electrically coupled to the generator and forming in-part with the generator and the first electrode a drive circuit and a reflected power monitoring circuit coupled to the drive circuit for monitoring power reflected back toward the generator from the first electrode. With this construction, occlusion and/or thermocoagulation can be accurately detected so that the power delivered to the first electrode when positioned in the mammal can be terminated. In this manner, the risk of overheating tissue in the vicinity of the constricted vessel is minimized or eliminated.
The present invention provides a device and method for occluding the body lumen including the cystic duct, wherein, in one embodiment, the device has a tapered end and an expandable segment. In use, using a suitable access instrument, the tapered end of the device is inserted into the cystic duct and the expandable segment may be expanded to lodge the device in the duct and to occlude the duct. The access instrument may then be detached from the device and withdrawn. The device is left in the duct, acting as a plug.
Body lumens such as blood vessels are selectively occluded by applying radiofrequency voltage to a vaso-occlusive coil (100) at the target site (TS) and generating a thermal reaction to induce fibrogenic occlusion of the blood vessel (BV) around the vaso-occlusive coil. The radiofrequency current is usually sufficient to induce thermal damage to the luminal wall and to coagulate the surrounding blood, thereby initiating clotting and subsequent fibrosis to permanently occlude the lumen. The invention also includes a method for endoluminally deploying the vaso-occlusive coil and preventing migration of the coil from of the target site.
The present invention provides an apparatus and method for performing rf intraluminal reduction and/or occlusion with a virtual electrode. An apparatus in accord with the present invention includes a catheter and a guide wire. The guide wire includes a conductive core having a proximal end electrically connected to a generator of rf current and an exposed distal end. An insulative material having disposed therein at least one microlumen for providing a conductive fluid to a target site within the lumen encases the guide wire. In a method in accord with the present invention, an rf conductive fluid is introduced at the target site in a body lumen. Radio frequency current is applied to the site by a conductive electrode through the conductive fluid, causing the connective tissues in the lumen walls to heat and contract. Application of the rf current is discontinued when the lumen wall has contracted or been reduced to the desired extent, which will often be complete occlusion.
A system and method of generating RF includes an RF generator, a variable DC power supply, and a comparator. The RF generator has an RF output coupled to an input of the transducer. The variable DC power supply has a control input and a DC output coupled to the RF generator. The comparator includes a first input coupled to a set point control signal, a second input coupled to the RF generator RF output, and a control signal output coupled to a voltage control input on the variable DC power supply.
A system and method of providing RF to a transducer includes an oscillator, an RF generator, and a voltage phase detector. The oscillator has a frequency control input and an RF signal output. The RF generator has an input coupled to the oscillator RF signal output and an RF generator output coupled to the transducer. The voltage phase detector includes a first phase input coupled to the RF signal output of the oscillator, a second phase input coupled to the RF generator output, and a frequency control signal output coupled to the oscillator frequency control voltage input.
