of 66 a is depressed causing roller 76 and roller 78 to crimp and preferably sever the extended sealable section 28 of guidewire assembly 22 severing of the extended sealable section 28 serves as an immediate verification of the creation of an effective seal sealing mechanism 68 or 68 a can be released and guidewire assembly 22 can be completely removed from the sealing system 60 or 60 a allowing the occlusive balloon 32 to remain inflated while occlusive substance treatment occurs following treatment the extended sealable section 28 can be sheared or broken off resulting in the deflation of the occlusive balloon 32 if occlusive treatment is complete guidewire assembly 22 can be removed from the vessel lumen if additional treatment is required extended sealable section 28 can be reattached to sealing system 60 or 60 a through first aperture 62 sealing mechanism 68 or 68 a can be retightened and the evacuation inflation process can be repeated in a preferred embodiment of the present invention the guidewire assembly 22 is utilized as the guidewire for an atherectomy or thrombectomy procedure of the type described in u s pat nos 5 370 609 or 5 496 267 the disclosures of both of which are hereby incorporated by reference in each of these procedures the guidewire assembly 22 is introduced into the patient the occlusive balloon.