Abstract: A catheter apparatus includes a lesion dilating member disposable at a lesion position in a vessel (e.g. a patient's artery) which is dilatable to open the vessel at the lesion position. An emboli-capturing assembly having a perfusion member and filter is displaced downstream from the lesion dilating member to capture embolic debris released in the fluid flow. The perfusion member may illustratively have peaks and channels formed between adjacent peaks which cooperate with the filter to create trapping pockets that capture embolic debris. The filter may be made from any flexible and porous material with dimensions to pass the fluid and block the emboli. The perfusion member is thereafter deflated to provide for emboli retention in the perfusion member.