Abstract: An apparatus and method are disclosed for accurately detecting the detachment of both electrically conductive and non-conductive implants which have been introduced to and are intended to remain at a desired therapeutic site. The detachment detection apparatus may include a conductive or an electrically-isolated implant, such as a vasoocclusive coil, connected to a wire by an electrolytically severable joint. The detachment assembly further includes a power supply having a direct current drive circuit for supplying a direct current to the joint, an alternating current drive circuit for independently supplying an alternating current to the joint, and an alternating current monitoring circuit for monitoring an alternating current level of the alternating current supplied to the joint. The detection assembly includes a central processing unit for selecting a first mode and a second mode for determining a detachment threshold level indicating detachment of the implant.

Abstract: 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.

Abstract: This invention is a method for ensuring for endovascular occlusion through the formation of thrombi in arteries, veins, aneurysms, vascular malformations, and arteriovenous fistulas. In particular, it deals with a method to predictably determine the instant of electrolytic detachment of an embolic device which is introduced to and is intended to remain at the desired thrombus formation site. The invention further includes a method for delivering an embolic device and detecting its electrolytic separation. According to the present invention, DC power with AC superposition is delivered to the sacrificial link that couples a delivery member (e.g., a guidewire) to an occlusion device. The impedance (as measured by the amplitude of the superposed AC) is monitored. When a predetermined change in that impedance (or amplitude occurs), which indicates coil detachment, the DC power is interrupted to minimize or avoid further electrolysis.

Abstract: This invention is a method for ensuring for endovascular occlusion through the formation of thrombi in arteries, veins, aneurysms, vascular malformations, and arteriovenous fistulas. In particular, it deals with a method to predictably determine the instant of electrolytic detachment of an embolic device which is introduced to and is intended to remain at the desired thrombus formation site. The invention further includes a method for delivering an embolic device and detecting its electrolytic separation.