A gas inflation/evacuation system incorporating a multiple element valved guidewire assembly having an occlusive device for use in thrombectomy or other vascular procedures includes a multiple element valved guidewire assembly having an occlusive balloon removably and sealingly connectible to an included manifold assembly where a guidewire tube defines a lumen for inflation or deflation of the occlusive balloon. A first syringe for evacuating the lumen and a second syringe for introducing a biocompatible gas into the lumen to inflate the occlusive balloon that is in fluid communication with the lumen a plurality of times are included. A sealing valve arrangement selectively seals the proximal portion of the guidewire tube to control inflated or deflated states of the occlusive balloon.